Silicone Elastomers

Silicone Elastomers

Report 137

Volume 12, Number 5, 2001

P. Jerschow

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Item 1Macromolecules

33, No.6, 21st March 2000, p.2171-83EFFECT OF THERMAL HISTORY ON THE RHEOLOGICALBEHAVIOR OF THERMOPLASTIC POLYURETHANESPil Joong Yoon; Chang Dae HanAkron,University

The effect of thermal history on the rheological behaviour of ester- andether-based commercial thermoplastic PUs (Estane 5701, 5707 and 5714from B.F.Goodrich) was investigated. It was found that the injectionmoulding temp. used for specimen preparation had a marked effect on thevariations of dynamic storage and loss moduli of specimens with timeobserved during isothermal annealing. Analysis of FTIR spectra indicatedthat variations in hydrogen bonding with time during isothermal annealingvery much resembled variations of dynamic storage modulus with timeduring isothermal annealing. Isochronal dynamic temp. sweep experimentsindicated that the thermoplastic PUs exhibited a hysteresis effect in theheating and cooling processes. It was concluded that the microphaseseparation transition or order-disorder transition in thermoplastic PUs couldnot be determined from the isochronal dynamic temp. sweep experiment.The plots of log dynamic storage modulus versus log loss modulus variedwith temp. over the entire range of temps. (110-190C) investigated. 57 refs.

GOODRICH B.F.USA

Accession no.771897

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Previous Titles Still AvailableVolume 1Report 3 Advanced Composites, D.K. Thomas, RAE, Farnborough.

Report 4 Liquid Crystal Polymers, M.K. Cox, ICI, Wilton.

Report 5 CAD/CAM in the Polymer Industry, N.W. Sandlandand M.J. Sebborn, Cambridge Applied Technology.

Report 8 Engineering Thermoplastics, I.T. Barrie, Consultant.

Report 11 Communications Applications of Polymers,R. Spratling, British Telecom.

Report 12 Process Control in the Plastics Industry,R.F. Evans, Engelmann & Buckham Ancillaries.

Volume 2Report 13 Injection Moulding of Engineering Thermoplastics,

A.F. Whelan, London School of Polymer Technology.

Report 14 Polymers and Their Uses in the Sports and LeisureIndustries, A.L. Cox and R.P. Brown, RapraTechnology Ltd.

Report 15 Polyurethane, Materials, Processing andApplications, G. Woods, Consultant.

Report 16 Polyetheretherketone, D.J. Kemmish, ICI, Wilton.

Report 17 Extrusion, G.M. Gale, Rapra Technology Ltd.

Report 18 Agricultural and Horticultural Applications ofPolymers, J.C. Garnaud, International Committee forPlastics in Agriculture.

Report 19 Recycling and Disposal of Plastics Packaging,R.C. Fox, Plas/Tech Ltd.

Report 20 Pultrusion, L. Hollaway, University of Surrey.

Report 21 Materials Handling in the Polymer Industry,H. Hardy, Chronos Richardson Ltd.

Report 22 Electronics Applications of Polymers, M.T.Goosey,Plessey Research (Caswell) Ltd.

Report 23 Offshore Applications of Polymers, J.W.Brockbank,Avon Industrial Polymers Ltd.

Report 24 Recent Developments in Materials for FoodPackaging, R.A. Roberts, Pira Packaging Division.

Volume 3Report 25 Foams and Blowing Agents, J.M. Methven, Cellcom

Technology Associates.

Report 26 Polymers and Structural Composites in CivilEngineering, L. Hollaway, University of Surrey.

Report 27 Injection Moulding of Rubber, M.A. Wheelans,Consultant.

Report 28 Adhesives for Structural and EngineeringApplications, C. O’Reilly, Loctite (Ireland) Ltd.

Report 29 Polymers in Marine Applications, C.F.Britton,Corrosion Monitoring Consultancy.

Report 30 Non-destructive Testing of Polymers, W.N. Reynolds,National NDT Centre, Harwell.

Report 31 Silicone Rubbers, B.R. Trego and H.W.Winnan,Dow Corning Ltd.

Report 32 Fluoroelastomers - Properties and Applications,D. Cook and M. Lynn, 3M United Kingdom Plc and3M Belgium SA.

Report 33 Polyamides, R.S. Williams and T. Daniels,T & N Technology Ltd. and BIP Chemicals Ltd.

Report 34 Extrusion of Rubber, J.G.A. Lovegrove, NovaPetrochemicals Inc.

Report 35 Polymers in Household Electrical Goods, D.Alvey,Hotpoint Ltd.

Report 36 Developments in Additives to Meet Health andEnvironmental Concerns, M.J. Forrest, RapraTechnology Ltd.

Volume 4Report 37 Polymers in Aerospace Applications, W.W. Wright,

University of Surrey.

Report 39 Polymers in Chemically Resistant Applications,D. Cattell, Cattell Consultancy Services.

Report 41 Failure of Plastics, S. Turner, Queen Mary College.

Report 42 Polycarbonates, R. Pakull, U. Grigo, D. Freitag, BayerAG.

Report 43 Polymeric Materials from Renewable Resources,J.M. Methven, UMIST.

Report 44 Flammability and Flame Retardants in Plastics,J. Green, FMC Corp.

Report 45 Composites - Tooling and Component Processing,N.G. Brain, Tooltex.

Report 46 Quality Today in Polymer Processing, S.H. Coulson,J.A. Cousans, Exxon Chemical International Marketing.

Report 47 Chemical Analysis of Polymers, G. Lawson, LeicesterPolytechnic.

Volume 5Report 49 Blends and Alloys of Engineering Thermoplastics,

H.T. van de Grampel, General Electric Plastics BV.

Report 50 Automotive Applications of Polymers II,A.N.A. Elliott, Consultant.

Report 51 Biomedical Applications of Polymers, C.G. Gebelein,Youngstown State University / Florida Atlantic University.

Report 52 Polymer Supported Chemical Reactions, P. Hodge,University of Manchester.

Report 53 Weathering of Polymers, S.M. Halliwell, BuildingResearch Establishment.

Report 54 Health and Safety in the Rubber Industry, A.R. Nutt,Arnold Nutt & Co. and J. Wade.

Report 55 Computer Modelling of Polymer Processing,E. Andreassen, Å. Larsen and E.L. Hinrichsen, Senter forIndustriforskning, Norway.

Report 56 Plastics in High Temperature Applications,J. Maxwell, Consultant.

Report 57 Joining of Plastics, K.W. Allen, City University.

Report 58 Physical Testing of Rubber, R.P. Brown, RapraTechnology Ltd.

Report 59 Polyimides - Materials, Processing and Applications,A.J. Kirby, Du Pont (U.K.) Ltd.

Report 60 Physical Testing of Thermoplastics, S.W. Hawley,Rapra Technology Ltd.

Volume 6Report 61 Food Contact Polymeric Materials, J.A. Sidwell,

Rapra Technology Ltd.

Report 62 Coextrusion, D. Djordjevic, Klöckner ER-WE-PA GmbH.

Report 63 Conductive Polymers II, R.H. Friend, University ofCambridge, Cavendish Laboratory.

Report 64 Designing with Plastics, P.R. Lewis, The Open University.

Report 65 Decorating and Coating of Plastics, P.J. Robinson,International Automotive Design.

Report 66 Reinforced Thermoplastics - Composition, Processingand Applications, P.G. Kelleher, New Jersey PolymerExtension Center at Stevens Institute of Technology.

Report 67 Plastics in Thermal and Acoustic Building Insulation,V.L. Kefford, MRM Engineering Consultancy.

Report 68 Cure Assessment by Physical and ChemicalTechniques, B.G. Willoughby, Rapra Technology Ltd.

Report 69 Toxicity of Plastics and Rubber in Fire, P.J. Fardell,Building Research Establishment, Fire Research Station.

Report 70 Acrylonitrile-Butadiene-Styrene Polymers,M.E. Adams, D.J. Buckley, R.E. Colborn, W.P. Englandand D.N. Schissel, General Electric Corporate Researchand Development Center.

Report 71 Rotational Moulding, R.J. Crawford, The Queen’sUniversity of Belfast.

Report 72 Advances in Injection Moulding, C.A. Maier,Econology Ltd.

Volume 7

Report 73 Reactive Processing of Polymers, M.W.R. Brown,P.D. Coates and A.F. Johnson, IRC in Polymer Scienceand Technology, University of Bradford.

Report 74 Speciality Rubbers, J.A. Brydson.

Report 75 Plastics and the Environment, I. Boustead, BousteadConsulting Ltd.

Report 76 Polymeric Precursors for Ceramic Materials,R.C.P. Cubbon.

Report 77 Advances in Tyre Mechanics, R.A. Ridha, M. Theves,Goodyear Technical Center.

Report 78 PVC - Compounds, Processing and Applications,J.Leadbitter, J.A. Day, J.L. Ryan, Hydro Polymers Ltd.

Report 79 Rubber Compounding Ingredients - Need, Theoryand Innovation, Part I: Vulcanising Systems,Antidegradants and Particulate Fillers for GeneralPurpose Rubbers, C. Hepburn, University of Ulster.

Report 80 Anti-Corrosion Polymers: PEEK, PEKK and OtherPolyaryls, G. Pritchard, Kingston University.

Report 81 Thermoplastic Elastomers - Properties and Applications,J.A. Brydson.

Report 82 Advances in Blow Moulding Process Optimization,Andres Garcia-Rejon,Industrial Materials Institute,National Research Council Canada.

Report 83 Molecular Weight Characterisation of SyntheticPolymers, S.R. Holding and E. Meehan, RapraTechnology Ltd. and Polymer Laboratories Ltd.

Report 84 Rheology and its Role in Plastics Processing,P. Prentice, The Nottingham Trent University.

Volume 8

Report 85 Ring Opening Polymerisation, N. Spassky, UniversitéPierre et Marie Curie.

Report 86 High Performance Engineering Plastics,D.J. Kemmish, Victrex Ltd.

Report 87 Rubber to Metal Bonding, B.G. Crowther, RapraTechnology Ltd.

Report 88 Plasticisers - Selection, Applications and Implications,A.S. Wilson.

Report 89 Polymer Membranes - Materials, Structures andSeparation Performance, T. deV. Naylor, The SmartChemical Company.

Report 90 Rubber Mixing, P.R. Wood.

Report 91 Recent Developments in Epoxy Resins, I. Hamerton,University of Surrey.

Report 92 Continuous Vulcanisation of Elastomer Profiles,A. Hill, Meteor Gummiwerke.

Report 93 Advances in Thermoforming, J.L. Throne, SherwoodTechnologies Inc.

Report 94 Compressive Behaviour of Composites,C. Soutis, Imperial College of Science, Technologyand Medicine.

Report 95 Thermal Analysis of Polymers, M. P. Sepe, Dickten &Masch Manufacturing Co.

Report 96 Polymeric Seals and Sealing Technology, J.A. Hickman,St Clair (Polymers) Ltd.

Volume 9

Report 97 Rubber Compounding Ingredients - Need, Theoryand Innovation, Part II: Processing, Bonding, FireRetardants, C. Hepburn, University of Ulster.

Report 98 Advances in Biodegradable Polymers, G.F. Moore &S.M. Saunders, Rapra Technology Ltd.

Report 99 Recycling of Rubber, H.J. Manuel and W. Dierkes,Vredestein Rubber Recycling B.V.

Report 100 Photoinitiated Polymerisation - Theory andApplications, J.P. Fouassier, Ecole Nationale Supérieurede Chimie, Mulhouse.

Report 101 Solvent-Free Adhesives, T.E. Rolando, H.B. FullerCompany.

Report 102 Plastics in Pressure Pipes, T. Stafford, RapraTechnology Ltd.

Report 103 Gas Assisted Moulding, T.C. Pearson, Gas Injection Ltd.

Report 104 Plastics Profile Extrusion, R.J. Kent, TangramTechnology Ltd.

Report 105 Rubber Extrusion Theory and Development,B.G. Crowther.

Report 106 Properties and Applications of ElastomericPolysulfides, T.C.P. Lee, Oxford Brookes University.

Report 107 High Performance Polymer Fibres, P.R. Lewis,The Open University.

Report 108 Chemical Characterisation of Polyurethanes,M.J. Forrest, Rapra Technology Ltd.

Volume 10

Report 109 Rubber Injection Moulding - A Practical Guide,J.A. Lindsay.

Report 110 Long-Term and Accelerated Ageing Tests on Rubbers,R.P. Brown, M.J. Forrest and G. Soulagnet,Rapra Technology Ltd.

Report 111 Polymer Product Failure, P.R. Lewis,The Open University.

Report 112 Polystyrene - Synthesis, Production and Applications,J.R. Wünsch, BASF AG.

Report 113 Rubber-Modified Thermoplastics, H. Keskkula,University of Texas at Austin.

Report 114 Developments in Polyacetylene - Nanopolyacetylene,V.M. Kobryanskii, Russian Academy of Sciences.

Report 115 Metallocene-Catalysed Polymerisation, W. Kaminsky,University of Hamburg.

Report 116 Compounding in Co-rotating Twin-Screw Extruders,Y. Wang, Tunghai University.

Report 117 Rapid Prototyping, Tooling and Manufacturing,R.J.M. Hague and P.E. Reeves, Edward MackenzieConsulting.

Report 118 Liquid Crystal Polymers - Synthesis, Properties andApplications, D. Coates, CRL Ltd.

Report 119 Rubbers in Contact with Food, M.J. Forrest andJ.A. Sidwell, Rapra Technology Ltd.

Report 120 Electronics Applications of Polymers II, M.T. Goosey,Shipley Ronal.

Volume 11

Report 121 Polyamides as Engineering Thermoplastic Materials,I.B. Page, BIP Ltd.

Report 122 Flexible Packaging - Adhesives, Coatings andProcesses, T.E. Rolando, H.B. Fuller Company.

Report 123 Polymer Blends, L.A. Utracki, National ResearchCouncil Canada.

Report 124 Sorting of Waste Plastics for Recycling, R.D. Pascoe,University of Exeter.

Report 125 Structural Studies of Polymers by Solution NMR,H.N. Cheng, Hercules Incorporated.

Titles Available in the Current Volume

Volume 12

Report 133 Advances in Automation for Plastics InjectionMoulding, J. Mallon, Yushin Inc.

Report 134 Infrared and Raman Spectroscopy of Polymers,J.L. Koenig, Case Western Reserve University.

Report 135 Polymers in Sport and Leisure, R.P. Brown.

Report 136 Radiation Curing, R.S. Davidson, DavRad Services.

Report 137 Silicone Elastomers, P. Jerschow, Wacker-ChemieGmbH.

Report 138 Health and Safety in the Rubber Industry, N. Chaiear,Khon Kaen University.

Report 139 Rubber Analysis - Polymers, Compounds andProducts, M.J. Forrest, Rapra Technology Ltd.

Report 126 Composites for Automotive Applications, C.D. Rudd,University of Nottingham.

Report 127 Polymers in Medical Applications, B.J. Lambert andF.-W. Tang, Guidant Corp., and W.J. Rogers, Consultant.

Report 128 Solid State NMR of Polymers, P.A. Mirau,Lucent Technologies.

Report 129 Failure of Polymer Products Due to Photo-oxidation,D.C. Wright.

Report 130 Failure of Polymer Products Due to Chemical Attack,D.C. Wright.

Report 131 Failure of Polymer Products Due to Thermo-oxidation,D.C. Wright.

Report 132 Stabilisers for Polyolefins, C. Kröhnke and F. Werner,Clariant Huningue SA.

Silicone Elastomers

ISBN: 1-85957-297-9

Peter Jerschow

(Wacker-Chemie GmbH)

Silicone Elastomers

1

Contents

1. Introduction .............................................................................................................................................. 5

1.1 Nomenclature ....................................................................................................................................... 5

2. Silicone Elastomers Market .................................................................................................................... 6

3. Applications for Silicone Elastomers ..................................................................................................... 7

3.1 Automotive ..................................................................................................................................... 7

3.2 Healthcare and Medical .................................................................................................................. 9

3.3 Wire and Cable ..............................................................................................................................11

3.4 Sanitary, Household and Leisure .................................................................................................. 13

3.5 Transmission and Distribution ...................................................................................................... 16

3.6 Electronics .................................................................................................................................... 17

3.7 Mould Making .............................................................................................................................. 20

3.8 Food Sector ................................................................................................................................... 21

3.9 Other ............................................................................................................................................. 23

3.9.1 Safety Applications ........................................................................................................... 233.9.2 Aerospace ......................................................................................................................... 243.9.3 Building Industry .............................................................................................................. 243.9.4 Pharmaceutical ................................................................................................................. 243.9.5 Spin Casting...................................................................................................................... 24

4. Composition and Function of Silicone Elastomers ............................................................................. 25

4.1 Introduction and Classifications ................................................................................................... 25

4.2 Properties of Silicone Elastomers ................................................................................................. 25

4.3 Chemistry and Curing Mechanisms of Silicone Elastomers ........................................................ 26

5. Room Temperature Vulcanising Silicone Elastomers ........................................................................ 27

5.1 General .......................................................................................................................................... 27

5.2 Condensation Curing RTVs .......................................................................................................... 28

5.3 RTV-1 for CIPG and FIPG ........................................................................................................... 28

5.4 RTV-1 for Baking Tray Coatings .................................................................................................. 29

5.5 Adhesive RTV-1 Materials ........................................................................................................... 29

5.6 Condensation Curing RTV-2 Systems .......................................................................................... 31

5.7 Mould Making Condensation Curing RTV-2 Materials ............................................................... 31

5.7.1 Speciality Mould Making RTV-2 Materials ..................................................................... 32

5.8 Condensation Curing RTV-2 Compounds for Encapsulation ...................................................... 32

5.9 Adhesives and Sealants Based on Condensation Curing RTV-2 Compounds ............................. 33

5.10 Addition Curing RTV-2 Systems .................................................................................................. 33

Silicone Elastomers

2

5.11 Silicone Gels ................................................................................................................................. 34

5.12 Addition Curing Systems for Mould Making ............................................................................... 35

5.13 Addition Cured RTV-2 Systems for Encapsulation ...................................................................... 35

5.14 Addition Cured RTV-2 Adhesives and Sealants ........................................................................... 36

5.15 Addition Cured RTV-2 Foam for Compressible Gaskets ............................................................. 36

6. Liquid Silicone Rubber ......................................................................................................................... 37

6.1 General .......................................................................................................................................... 37

6.2 Curing Mechanism of Liquid Silicone Rubbers ........................................................................... 37

6.3 Standard Liquid Silicone Rubbers ................................................................................................ 38

6.4 Speciality LRs ............................................................................................................................... 39

6.4.1 High Tear LR .................................................................................................................... 396.4.2 No Post Cure LR .............................................................................................................. 396.4.3 Heat Stabilised LR............................................................................................................ 406.4.4 Coolant Resistant LR (NPC) ............................................................................................ 416.4.5 Self Lubricating LR (NPC) .............................................................................................. 416.4.6 Oil Resistant LR (NPC) .................................................................................................... 426.4.7 Self Adhesive LR.............................................................................................................. 426.4.8 Electrically Conductive (Antistatic Silicone!) LR ........................................................... 466.4.9 Flame Retardant LR ......................................................................................................... 466.4.10 Extra Liquid Rubber (XLR®) ........................................................................................... 476.4.11 Other Types of LR ............................................................................................................ 47

6.5 Pigment Pastes .............................................................................................................................. 47

7. Solid Silicone Rubber ............................................................................................................................ 47

7.1 General .......................................................................................................................................... 47

7.2 Curing Mechanisms of Solid Silicone Rubbers ............................................................................ 48

7.2.1 Addition Cure ................................................................................................................... 487.2.2 Peroxide Cure ................................................................................................................... 49

7.3 Standard Solid Silicone Rubbers .................................................................................................. 49

7.4 Speciality HTV (all peroxide) ...................................................................................................... 50

7.4.1 High Tear HTV ................................................................................................................. 507.4.2 Economy High Tear HTV ................................................................................................ 507.4.3 Extrusion HTV ................................................................................................................. 507.4.4 Cable HTV........................................................................................................................ 507.4.5 Oil Resistant HTV (NPC)................................................................................................. 507.4.6 Electrically Conductive HTV ........................................................................................... 517.4.7 Super Heat Stable HTV .................................................................................................... 517.4.8 High Green Strength/Coolant Resistant HTV .................................................................. 527.4.9 Steam Resistant HTV ....................................................................................................... 527.4.10 Heat Conductive HTV ...................................................................................................... 527.4.11 HTV for Transmission and Distribution (T&D) Applications ......................................... 53

7.5 Addition Cured HTV .................................................................................................................... 53

7.5.1 Introduction ...................................................................................................................... 537.5.2 Addition Curing ................................................................................................................ 53

Silicone Elastomers

3

The views and opinions expressed by authors in Rapra Review Reports do not necessarily reflect those ofRapra Technology Limited or the editor. The series is published on the basis that no responsibility orliability of any nature shall attach to Rapra Technology Limited arising out of or in connection with anyutilisation in any form of any material contained therein.

7.5.3 Moulding: 1K Addition Cured HTV ................................................................................ 547.5.4 Moulding: 1K Self Adhesive Addition Cured HTV......................................................... 557.5.5 Moulding: 2K Addition Cured HTV ................................................................................ 557.5.6 Extrusion HTV ................................................................................................................. 567.5.7 Post Curing of Addition Cured HTV ............................................................................... 56

8. Processing Silicone Elastomers ............................................................................................................ 56

8.1 RTV-1 Systems ............................................................................................................................. 56

8.2 RTV-2 Systems ............................................................................................................................. 56

8.2.1 Mould Making: Flexible Moulds ..................................................................................... 578.2.2 Mould Making: Block Moulds ......................................................................................... 588.2.3 Mould Making: Skin Moulds ........................................................................................... 58

8.3 LR and HTV ................................................................................................................................. 58

8.3.1 Press Curing HTV ............................................................................................................ 588.3.2 Transfer Moulding HTV................................................................................................... 588.3.3 Injection Moulding LR and HTV ..................................................................................... 598.3.4 Extrusion of HTV ............................................................................................................. 628.3.5 Moulding HTV (General) ................................................................................................. 628.3.6 Calendering HTV ............................................................................................................. 638.3.7 Rollers ............................................................................................................................... 648.3.8 Bonding ............................................................................................................................ 64

9. Summary ................................................................................................................................................ 64

Additional References ................................................................................................................................... 65

Abbreviations and Acronyms ....................................................................................................................... 65

References from the Rapra Abstracts Database .............................................................................................. 67

Subject Index ....................................................................................................................................................... 153

Silicone Elastomers

4

Silicone Elastomers

5

1 Introduction

Silicone elastomers are elastic substances whichcontain linear silicone polymers crosslinked in a 3-dimensional network.

In most cases this network also contains a filler whichacts as a reinforcing agent or as an additive for certainmechanical, chemical or physical properties.

In general all silicones (usually we refer to silicones aspolydimethyl siloxanes) are noted for their high thermalstability, biocompatibility, hydrophobic nature,electrical and release properties. When silicones arecrosslinked to form a silicone rubber their characteristicproperties are still prevalent. Hence silicone elastomerscan be widely used in a great variety of applications.Some examples are shown in Table 1. These will bedescribed in more detail when concentrating on specificgroups of materials and applications.

We will not refer too much to silicone adhesives inthis article, in spite of the fact that they form siliconeelastomers when being cured. These materials havebeen referred to extensively in the literature (a.1, a.2).

1.1 Nomenclature

The nomenclature classifies silicone elastomers by theircuring mechanism and curing conditions. Siliconerubbers are essentially divided into two groups ofmaterials, i.e., room temperature vulcanising (RTV) andhigh temperature vulcanising (HTV). RTV systems areable to cure at room temperature and HTV systems attemperatures well above 100 °C. A number in the nameindicates the number of components that upon mixingwill form a curable composition, e.g., RTV-2.

HTV rubbers are mainly so-called solid silicone rubbers.They have a very high viscosity in the uncured state andappear as solids. This behaviour has also led to thecreation of the term ‘High Consistency Rubber’ (HCR).

Approximately 25 years ago a new group of materialsappeared that was intended for processing in injectionmoulding machines. Because of their low viscosity andpaste-like behaviour they were named liquid siliconerubbers (LSR) or simply liquid rubbers (LR). It iscommon to use LSR or LR as an abbreviation insteadof HTV, even though they vulcanise at hightemperatures as in the case of solid silicone rubbers.

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Silicone Elastomers

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For the most part all LR materials are 2 componentsystems which cure after mixing and at elevatedtemperatures.

In summary the silicone industry uses the terms RTV-1, RTV-2, LR or LSR, HTV or HCR. These refer to thematerial categories as follows:

RTV-1 Room temperature vulcanising, onecomponent

RTV-2 Room temperature vulcanising, twocomponent

HTV High temperature vulcanising, solidsilicone rubber, high consistency rubber

LR Liquid rubber, liquid silicone rubber (whichis also cured at high temperatures).

In this article I will concentrate on applications,requirements and materials and why to choose siliconeelastomers in the cases discussed.

The second half of this review will concentrate on thevarious types of silicone elastomers, their chemistryand processing.

2 Silicone Elastomers Market

In 1999 the global market consumed approximately170,000 tons of silicone elastomers.

Figure 1 shows the market shares between the materialcategories. Among all silicone elastomers LR exhibitsthe highest growth rate and HTV has the highest portionof the market.

Silicone Elastomers

7

Figure 1

Silicone elastomers world market by materialcategories

3 Applications for Silicone Elastomers

3.1 Automotive

Table 2 provides a rough overview of the most commonautomotive applications for silicone elastomers andindicates suitable silicone elastomers.

The specific requirements of car builders and theirsystem suppliers have made silicone elastomers anindispensable raw material for automotive components.

One should also mention that silicone fluids, fumedsilica, tyre release agents, paint additives, siliconepolish and resins are as indispensable for carcomponents as silicone elastomers.

The key reasons for the consumption of silicones inautomotive applications are numerous.

Heat resistance, cold flexibility, oil and chemicalresistance mainly account for the use of silicones inthe engine and areas close to the engine.

Long-term properties such as ‘infinite’ flexibility andlow compression set make silicones the perfect choicefor airbag coatings, gaskets, bellows, profiles, etc.

Very high dielectric strength and surface resistance, andhydrophobic behaviour are required in electricinstallations for cars. This, however, holds for most wireand cable applications. Apart from being ‘perfect’electrical insulators, silicone elastomers can be modifiedto become electrically conductive parts which are then

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swolleB X X

…deunitnoc

Silicone Elastomers

8

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1-VTR 2-VTR RL VTH

stnenopmoccinortcelednacirtcelE X X X X

)GPIC(teksaG-ecalP-nI-deruC X X

srepmadnoitarbiV X X X

steksagpalftneV X

sesohrotaidaR X

cinortcelednasteksaggninoitidnocriAstnenopmoc

X X X

sevlavretlifliO X X

teksagretlifriA X

rosnesssamwolfriA X X

steksagnapliO X X X

sgnir-O

seliforP X

steksaggnithgiL X X X X

egnopsenociliS X X

steksagfoornuS X

sesohregrahcobruT X

senarbmeM X X

noitcetorpliocnoitingI X X X

sedalbrepiW X X

steksag/metsyskcolrewoP X X

steksagdaehrednilyC X

steksagxobraeG X X

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ecnatsisergnissecorpysaE

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ecnatsisergnissecorpysaE

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scinortcelE noitalusnicirtcelE tnatsiserdloc/taeH ytirgetnimret-gnoL erutancibohpordyH

lacirtcelEsnoitallatsni

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tesnoisserpmocwoL ssecorpotysaE elbatsVU tnatsiserdloc/taeH

Silicone Elastomers

9

used, for example, in parts for the ignition system (suchas the ignition cable inner lead and spark plugs).

The dielectric and other properties make them suitablefor spark plug boots and encapsulation of electroniccomponents (even safety components such as airbagand ABS controls).

Any application related to the car body is subjected tomost of the property requirements already mentioned.UV stability is another predominant requirement forparts used in such applications.

The term ‘stability’ means that a material will notimmediately or slowly change its properties over timeon exposure to a certain condition. In other words, agiven mechanical and/or chemical parameter shouldchange as little as possible. In most casesspecifications include relative changes over time(changes in percentage of a property value comparedto the initial values). Property requirements forautomotive applications are shown in Table 3.

3.2 Healthcare and Medical

Table 4 provides a rough overview of the most commonapplications and suitable silicone elastomers in medicaldevices, healthcare applications and related areas.

The field of applications for silicone elastomers is aswide in medical applications as in the automotivesector. Furthermore this is a growing sector, becauseof the substitution of other organic elastomers, such aslatex, and thermoplastics, such as PVC.

Reportedly silicone elastomers have often beendiscussed as the ideal material for medical devices andapplications. This also includes the genetics,biotechnology and pharmaceutical industries.

The main reason for this great interest in silicone rubberis due to its biocompatibility. For example, siliconerubbers show:

NO pyrogenicity (NO body temperature reaction),NO haemolysis (NO red blood cell destruction) andNO cytotoxicity (do not affect live cells).

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snoitacilppA

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2-VTR RL VTH

sretehtaC X X X

sksamnoitaripseR X X X

swollebnoitaripseR X X

gnibutcitehtseanA X

srotcennocgnibuT X X

sedortceleydoB X X

stnuhseuqapoyar-X X X

sniardeuqapoyar-X X X

spitretehtaceuqapoyar-X X X

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X X

sdapmoorgnitarepO X X

srotabucnirofsdaP X X

snoollabretehtaC X

slennufretehtaC X X

stnenopmoccinortcelednacirtcelE X X X

sevlaV X X

…deunitnoc

Silicone Elastomers

10

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snoitacilppA


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sreppotS X X

steksaG X X

sgniR-O X

tnempiuqesisylaidrofsteksaG X X

stnemurtsninoitareporofsdaP X X

sedortceleydoB X X X

snotsipegniryS X X

sevlavgnisnepsidnoitacideM X X

sdianoitalahnI X X

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)yparehtoisyhprof(yttupgnicnuoB

senarbmeM X X

stnalpmimret-trohS X X

)lanretxe(secivedcitehtsorP X X X

knignitnirP X X

sessamlatneD X

gnipytotorpdipaR X

sdaplegenociliS X

tnempiuqecirosneS X X X

Thus correctly produced and treated silicone partsmade out of selected materials suitable for medicaldevices will pass tests according to ISO10993 andUS Pharmacopoeia Class VI, EuropeanPharmacopoeia and other protocols.

Figure 2 shows certificates from test laboratoriesas obtained on the biocompatibili ty ofELASTOSIL® R4110/60 and 4305/40, siliconeelastomers produced by Wacker.

The key reasons for the consumption of silicones inmedical/pharmaceutical devices and equipment are:biocompatibility, gamma ray resistance, chemicalresistance, sterilisability (gamma ray, ethylene oxide(EtO), steam), pigmentability, transparency,durability, and the fact that they are non allergenic.

In addition, all the properties mentioned under theautomotive section (3.1) also complement their

competitive advantages compared to other organicelastomers.

As many medical devices must be manufacturedunder special hygienic conditions, in compliancewith Good Manufacturing Practice (GMP), incleanrooms, silicones seem to be a good choice ofmaterials as well.

In many cases they can be processed almost withoutforming any reaction products, which might impairpurity, smell or sterility of the manufactured goods.

Silicones are not only bioinert, their excellentelectrical insulating properties make them a usefulcomponent of any medical equipment, be it sensoric,or for resuscitation, etc. This is also supported by theirhydrophobic behaviour, which prevents them fromaccumulating moisture from the surroundingenvironment.

Silicone Elastomers

11

Table 5 summarises most of the mentioned propertiesas they relate to areas where medical devices are mostcommonly used.

Summing up we can draw the conclusion thatsilicones have a great future in medical devicetechnology. However, their reputation as long-termimplants has been sullied after the bad press and thevast number of lawsuits with respect to siliconebreast implants.

In order to support the duty of care of suppliers to themedical device industry, in most cases siliconemanufacturers have set internal healthcare guidelines.Basically these list allowed applications for each

material and those that are not supported by the siliconemanufacturer. As a general rule, many siliconemanufacturers restrict their supply to this industry toshort-term implants. In other words, the providers ofsilicone elastomers will not usually support implantsor devices involving permanent body contact (longerthan 29 days).

3.3 Wire and Cable

Silicone rubbers are used for applying an electricallyinsulating layer onto the conductive thread of a cable.

Many of these insulations are made of HTV siliconerubber.

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sresiliretsmaetS ecnatsisertaeH ecnatsisermaetS ecnatsiserlacimehC erutancibohpordyH

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cinegrellaeuqapoyar-X

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tnempiuqecirtcelE noitalusnicirtcelE tnatsisertaeH htgnertscirtceleidhgiH erutancibohpordyH

Figure 2

Certificates on the biocompatibility of ELASTOSIL® R4110/60 and 4305/40

Silicone Elastomers

12

Increasingly, the latest development, i.e., pelletisedsilicone rubber is being used in such applications.Existing and innovative applications are shown inTable 6.

The specific requirements for silicone elastomers thatare used in cables develop from the requirements ofcable manufacturers and their end users.

As to manufacturers in particular, the silicone rubbermust be easily extrudable in order to allow outputs ofup to 400 m/min of ready made cable.

Typically cable insulations made of HTV will exhibita dielectric strength of 18-20 kV/mm and a volumeresistivity of 1015 Ωcm.

End users often specify their cables to comply withinternational and national standards, such as the VDEstandards. The most important requirement for thesilicone in this application is the heat resistance. TheVDE standard, VDE 0303, specifies an elongation atbreak of >200% after heat ageing for 10 days at200 °C.

The use of silicone rather than PVC or otherthermoplastic and elastomer materials, has beenboosted by safety discussions after recent fire accidentsin which most of the damage was unfavourablyattributed to the contribution of the PVC sleevings tosmoke toxicity and density and cable function. Silicone

cables burn at a much slower speed and theircombustion products have low toxicity.

During combustion silicone degrades to silica. Hence,most of the silicone forms an electrically insulatingash. This prevents short circuits and theirconsequences.

The accidents referred to above gave rise to the rapiddevelopment of so-called safety cables. Such cableswill maintain the integrity of the electric circuit overa certain period of time in the case of a fire. Usingspecial silicone grades, such as ELASTOSIL® R 502/75 from Wacker Chemie GmbH, enables cablemanufacturers to produce a safety cable which willmaintain circuit integrity over 90 minutes attemperatures higher than 1,000 °C even if they arequenched with water. This technology is based on thefact that ceramics are electrical insulators.ELASTOSIL® R 502/75 turns into a ceramic when itis being burned. It goes without saying that the safetyof such cables is also a question of design.

Very recent developments have led to addition curedsafety cable compounds and compounds which forman even harder ceramic. These are summarised inTable 7 (a.3).

A further competitive advantage of these safety cablematerials is the fact that they can be extruded at veryhigh speeds (of up to 400 m/min) whereas more

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2-VTR RL VTH VTHdesitelleP

selbactnatsiserraeW X X X X

selbactnemurtsnI X X

selbacyrettaB X X

selbaclangisytefaS X X

selbacrewopytefaS X X

selbacedargymonocE X X

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selbacetisopmoC X X X

gniveelselbaC X X X

selbacnoitingI X X

stelleprebburenocilismorfselbaC X

selbacegatlovmuidemdnahgiH X X

Silicone Elastomers

13

traditional safety cable technology allows only a fewmetres per minute. For example, mica tape safety cableshave a production rate of 12 m/minute.

Table 8 summarises most of the properties of siliconesrelevant to wire and cable applications.

Over the past years the cable markets have degeneratedinto a commodity business. In most cases the costpressure on industries related to consumer electronics,household appliances and car manufacturers was toohigh to maintain this as a speciality area.

Some cable markets were dominated by siliconerubbers that were heavily filled with quartz in orderto bring the cost down (silicone suppliers call this‘elastic stone’).

Today, cable manufacturers are in a renaissance as therequirements have changed. The safety and high qualityaspect seems to have gained priority over plain costcalculations.

Recently developed new technologies such assilicone rubber pellets, safety cable grades and wearresistant cables have also led to new applicationareas for silicone rubbers/elastomers used as cableinsulation material.

3.4 Sanitary, Household and Leisure

Apart from wires and cables described under theprevious chapter, sanitary and household appliancesutilise silicones in tap water equipment and domesticappliances.

Table 9 provides a rough overview of commonapplications and suitable silicone elastomers.

The consumption of silicones and, in particular, siliconeelastomers in household appliances and related areassuch as sanitary, gardening, agricultural and leisureequipment is enormous. The growth of suchapplications is often due to the substitution of otherorganic elastomers, such as EPDM and thermoplasticelastomers, etc.

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LISOTSALE ® 57/305R noitsubmocnognisimarec,erucedixorePcimarecredrahhcumsmroF

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LISOTSALE ® 07/345R noitsubmocnognisimarec,erucnoitiddA ssap,elbatnemgip,stellepnielbaliavAecnatsisertaehnostnemeriuqerEDV

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remirpgniveelselbaC noisehdadooG ecnatsiserraeW ytilibatnemgiP

Silicone Elastomers

14

In most cases the properties of silicone elastomersare more favourable than those of organic rubbers.Silicone elastomers allow a high degree ofautomation in processing. However, material costsare relatively high and cost is an important factor inthis application area.

As in most applications in this field mass production isprevalent, annual production is usually 100,000 or morepieces, hence the processing advantages of siliconerubber can drastically improve the cost structure.

In other words, when processing an elastomer the costof the ready made piece often depends on the processingcost per piece rather than the cost of the materialconsumed per piece.

Any difference in material cost between siliconeelastomers and other rubbers/elastomers is deceptivetherefore, because it does not indicate the differencesin the specific complexity and duration ofprocessing.

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1-VTRevisehda

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steksagnorilacirtcelE X X X X

steksagrekooceciR X X

tinugniximrofteksagretawpaT X X

sgnittifrofteksagretawpaT X

steksagrelioB X X

sroodenihcamgnihsawrofteksaG X X

senihcamgnihsawnisrepmadnoitarbiV X X

srehsawhsidrofsteksaG X X

sgnir-O X X

senihcamgnidnevrofgnibuT X

senihcamaetdnaeeffocrofsevlaV X X

steksagrekoocerusserP X X

stnenopmoc/steksagevaworciM X X X

)seliforp(slaesroodnevO X

).cte,rewomnwal(stoobgulpkrapS X X

snoitacilppaytefaS X X X

sevlaV X X

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steksaG X X

)PThtiwetisopmoc(selzzondaehrewohS X X

)sessalg(sdapesoN X X

spacgnimmiwS X X

smetsysnoitagirrirofsenarbmeM X X

senarbmeM X X

ksamgniviD X X

tnempiuqegniviD X X

Silicone Elastomers

15

In many cases silicone elastomers are processed withoutany major secondary operations. It is also possible toeliminate any manual steps in production. Theconsequence is a much higher accuracy and consistencyof the production process and substantial cost savings.

Silicone rubbers, when processed and post curedcorrectly do not usually affect the taste of thesurrounding media. Other properties such as lack ofcytotoxicity have been discussed in Section 3.2; thussilicone rubber is useful for tap water equipment.

In comparison to organic rubbers, silicone elastomersdo not contain any harmful substances such asnitrosamines. The nitrosamine level in silicones isbelow detection level or below the common limit of10 ppb after correct processing. The levels ofnitrosamines are higher in some organic rubbers. Theirorigin is thought to be in the curing system whichcontains amines. As a consequence, apart from theeffect on smell and taste, nitrosamines remain in therubber (a significant proportion are non volatile, andthus would not evaporate over time).

In drinking water applications a number of internationaland national regulations apply, administered by: The

National Sanitation Foundation (NSF) in the US, WaterRegulations Advisory Scheme (WRAS) in the UK, andthe KTW guidelines in Germany, etc.

Silicones are suitable for most of these standards.Producers of raw materials usually have a number ofsuitable materials with a KTW or WRAS certificate.

These certificates also include colours, as shown inFigure 3. Even though many materials are containedin such certificates, the end seller will have to producea separate approval certificate for his own system.

In this area of applications design aspects are ofimportance, such as pigmentability and transparency.

Further, compared to other plastics or rubbers, standardsilicones will produce no toxic gases and low smokedensity should they burn. Additionally, standardsilicones will have lower inflammability than organicrubbers. Thus, all silicone rubbers would pass a UL94HB flame test (a.4). Special additives can be used toincrease this further, resulting even in UL94 V0 ratings.

Table 10 summarises most of the properties of siliconeelastomers related to household and similar areas.

Figure 3

WRAS and KTW certificates (reproduced with permission)

Silicone Elastomers

16

3.5 Transmission and Distribution

These applications cover the transmission and distributionof electric power. Special silicones are the best choice formedium and high voltage cable accessories and insulatorsas described below.

Historically, the transmission and distributionapplications for silicones developed from normalporcelain insulators which were covered with siliconegrease in order to achieve hydrophobicity. Later,silicone rubber dispersions were used to cover porcelainwith a rubbery and hydrophobic layer.

Today, after 30 years of development, insulators tendto consist entirely of special silicone rubbers. Most ofthem contain special fillers allowing for more enhancedelectrical properties.

The technology of silicone rubber pellets is also availablefor these special grades resulting in processing advantages.

For performance reasons silicones are increasinglyused in these areas as ceramics and organic rubbersdo not show the same degree of performance,particularly in medium and high voltageapplications. Table 11 gives a list of key applicationsand the silicone elastomer type used.

Even though the number of applications listed in theabove table is seemingly quite small therequirements are various and the scope of theseapplications is enormous.

The most important properties are based on theelectrical parameters of silicone rubbers, such asdielectric strength (around 18-20 kV/mm), volumeresistivity (1015 Ωcm) and surface resistance(1013 Ω). As yet mentioned under earlier chaptersthese properties are the reason for the suitability ofsilicone rubbers for electrical applications.

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seirosseccaelbaC X X X

srotcennocknirhsdloC X X

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srotalusniegatlovhgihdnamuideM X X X

srebburenocilisevitcudnoC X X

sremirpevitcudnoC X

Silicone Elastomers

17

A further asset of silicones is their hydrophobicbehaviour which is of importance in many outdoortransmission and distribution applications. As a resultof their hydrophobic nature, silicone insulators showmuch smaller leakage currents than porcelain or EPDMoffsets. Even in cases of high contamination (even ifconductive!) silicone insulators will remainhydrophobic along their surface. Silicone elastomersare capable of turning deposits from their environment(such as dust, sea salt, etc.) hydrophobic. This is dueto the small amount of siloxanes bleeding out of theelastomer surface, covering the deposit and renderingit hydrophobic.

Even after cleaning the insulators with detergents thehydrophobic behaviour will remain or return in duecourse. This is called hydrophobic transfer andregeneration.

Insulators in outdoor applications often are in contactwith moisture. This is why tracking resistance is ofutmost importance, silicone rubbers for these situationshave tracking resistance >2.5kV. (Special siliconegrades provide a tracking resistance of ≥4kV.)

Should flashovers take place special silicone elastomersalso exhibit excellent resistance to electric arcs.

Needless to say, as silicone elastomers have relativelylow changes of properties over time and temperaturethey are very suitable for long-term applications and forvarying conditions. Silicone elastomer insulators canresist temperatures down to –45 °C, remaining flexible.

UV and ozone resistance complement the spectrumof properties.

Table 12 summarises the properties required fordifferent application areas, where specialty siliconerubbers are used in the transmission and distributionindustries.

Long life, resistance to severe conditions and otherproperties make silicone elastomers suitable materialfor electric insulators in transmission and distributionapplications. This is particularly of importance whereelectric energy must be distributed in desert or coastalareas, where the most severe conditions occur.

3.6 Electronics

Silicone elastomers are highly rated materials forelectronic components. Their main use is encapsulationand in composites, as summarised in Table 13. Manyapplications in this sector can also be referred to ashousehold, automotive, consumer, etc., applications.However, they are dealt with in this section as theirmain purpose is to protect and/or allow the performanceof electronic components.

HTV, LR or RTV-1 silicones are only used in a fewcases. This has to do with the fact that electroniccomponents are too sensitive chemically for RTV-1 andmechanically for LR or HTV to allow for their use(Table 13).

For encapsulation of electronic components, potableRTV-2 systems provide the best solution. Typically, theyare transparent or opaque and exhibit low viscosities orthixotropic behaviour. Their pot life is long and theircuring time is very short, in particular after slight heatingof the mix. In order to provide maximum performancewith respect to electrical properties and corrosivebehaviour their ion content is very low. Special systemswill perform well down to –100 °C. As to vibrations,shocks, etc., they provide maximum mechanicalprotection of the encapsulated electronic system due totheir mechanical damping properties.

One of the most popular electronic applications in theautomotive sector are so-called weather packs. Theseare described in Section 6.4.5 of this review. In mostcases one would use oil exuding LR.

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esuroodtuO erutancibohpordyH ecnatsisergnikcarT ecnatsisercrA cirtceleidhgiHhtgnerts

Silicone Elastomers

18

Maximum reliability is crucial in safety applicationssuch as ABS and airbag control or medical electronicequipment, for instance.

This requires optimum adhesion to circuit boards andhousing, low modulus (thus high flexibility) and theabsence of solvents, the latter is also required forenvironmental compatibility.

Some applications require very high thermalconductivity (to allow for the transfer of heat), materialsup to 2.0 W/mK are used for such applications. Forexample, thermal conductivity is a must for sensoricequipment, e.g., for temperature measurement.

As mentioned earlier silicones are excellent electricalinsulators. This, their mechanical properties and theirhydrophobic character make them suitable forelectronics.

Needless to say, easy processing is a must. This allowsfor high output rates in processing and a good degreeof flexibility.

A good example of a consumer electronic applicationare anode caps for TV sets. Typically, they would alsobe part of electroencephalogram (EEG),electrocardiogram (ECG) and related equipment, andall applications requiring high voltage such as in thecase of anodes of tubes for TV screens. Therequirements are very high dielectric strength, flameand heat resistance. As anode caps, safety switches,etc., originate from moulding processes, it is alsorequired that the curing times be very short.

Table 14 shows inflammability ratings and limitingoxygen indices of various liquid silicone rubbers andHTVs including the Underwriters’ Laboratory (UL)classifications (a.4).

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slortnocnoitingI X X

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srosneS X X X

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spacedonA X X

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Silicone Elastomers

19

Materials for electronic key pads require utmostdurability (number of cycles of pressed keys), very highresistivity and pigmentability. Most key pads are alsopainted and/or printed with special inks. Good adhesionof such inks complements the requirements. Specialink formulations provide excellent adhesion and wearresistance. They are, of course, silicone based.

Cellular phones, radios and electronic controls oftenwork with electromagnetic signals. In order to shieldtheir electronic interior one has to use special housings.These housings are sealed with gaskets which act asan electromagnetic shield. As with all gaskets they haveto be elastic over a wide range of conditions. Thus,silicone is the best choice. Special silicones areequipped with highly conductive additives that allowfor sufficient shielding. Rapid curing and adhesiveproperties are further complementing properties. Thesilicone elastomers are applied by robots onto plasticframes and/or housing.

Special silicone elastomers are also applied in themanufacture of electronic chips and for solar cells inaerospace applications. This implies UV stability,resistance against irradiation, low volatiles andoptimum adhesion.

Such properties allow their use in power modules suchas components of rectifiers, welding equipment,elevators, etc.

Optocouplers often contain RTV-2 silicone gelsbecause of their high transparency. Such gels can bemade thixotropic by certain additives which allowspartial coverage. Good electrical properties andinsensitivity to thermomechanical stress andtemperature changes complement the advantages ofthe use of silicone gels.

One of the most important properties of siliconeelastomers in electronics is long-term integrity. Thisallows for their use in long lasting sensors andencapsulated circuit boards.

Apart from the minor part of applications in electronicsthat are produced by injection moulding such as anodecaps (with the exception of weather packs), most ofthe products are produced by using potting technology.

As this technology refers to electronics for the mostpart it will be described briefly.

Potting is a technology that is used in order to protectelectronic devices. Fully automatic processing involvessingle or multicomponent mixing and meteringequipment. This apparatus is usually part of a massproduction process. Silicone elastomers in use here aredesigned for simple mixing ratios and the individualcomponents in most cases have viscosities of the sameorder of magnitude. Fully automatic and highlyaccurate application techniques have evolved.

Potting is used in covering chips, hybrid circuits, powermodules and other devices.

RTV-1 and RTV-2 UV curing systems are known aswell as HTV, 1- and 2-component materials.

Potting compounds can be very soft and flexible, butalso rigid or highly elastic. Soft gels are recommendedfor covering highly sensitive components. Pottingsystems can be:

• low viscosity or thixotropic

• highly transparent

• flame retardant

• thermally conductive

• fuel resistant

• cold resistant

• resistant against thermal shock

• low shrinkage

• adhesive to plastics

• low volatile (low outgassing)

• good damping properties.

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Silicone Elastomers

20

Table 15 summarises most of the properties requiredfor applications in electronics.

3.7 Mould Making

Whenever I mention mould making in conjunctionwith RTV materials or in the present chapter, I donot mean the construction of moulds for injectionor press moulding, as required for the processing ofLR and HTV.

Silicone elastomers are used in the production offlexible moulds for pourable, spreadable or paste-like materials which solidify in certain conditionsand subsequently lead to variously shaped products.Some of these applications might also be describedas household, automotive, consumer, semiconductor,etc. However, they differ from the previous sectionsbecause the silicone is used to make parts of adifferent material which is not necessarilyelastomeric.

All mould making materials are limited to RTV-2systems. A distinction is made between condensationand addition curing systems. This is based on thereaction mechanisms of the two systems.

Table 16 describes the applications of siliconeelastomers in mould making.

The main intention of mould making in theseapplications is quick and simple reproduction ofcertain shapes. This is the case if one wants to copya unique original, to duplicate a master copy, or aprototype, or to repair damage.

As each mouldable material has its specificcharacteristics, the range of available mouldmaterials is broad.

The biggest requirement for a mould making materialis chemical resistance, as the chemical nature of mostmouldable materials is at least slightly aggressiveunder moulding conditions. Chemical resistance ischaracterised by the change of a certain property overtime. If this change is relatively small, the mouldmaking material will allow a very high number ofmoulding cycles. This number would obviously belowered drastically as a consequence of, e.g.,premature embrittlement, which can be caused byexcessive heat. This would be the case if one uses anorganic rubber with relatively low heat resistancecompared to silicone.

Flexibility is possibly the second most importantproperty of silicone elastomers in mould making.

The mould should be capable of accuratelyreproducing the surface details of the original design.However, at the same time it must allow for optimumrelease properties. Silicone elastomers have a uniquechemical structure, which is responsible for suchrelease properties (as a result of the highlyhydrophobic nature).

Block moulds are produced by pouring or impressiontechniques. This is mainly done if one has to copyonly one side of the original, and it will allow onlyfor ‘shallow’ undercuts. Small models with simpleundercuts are made from block moulds of two or moreparts by pouring or impression.

Copying deeper undercuts requires skin moulds asobtained by spreading, dipping or pouring. Suchmoulds need a rigid mechanical support, such as plasteror laminate. If undercuts become more complicated onewill use a skin mould of two or more parts (using aspreading technique for bigger upright objects).

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Silicone Elastomers

21

Reproduction materials suitable for use in siliconemoulds are:

• Plaster, cement, concrete, synthetic stone or ceramics

• Waxes

• Casting resins such as polyesters, polyurethaneresins and foams, epoxy resins and, within limits,acrylic resins

• Low-melting metal alloys (melting points below350 °C).

3.8 Food Sector

The reader may have guessed from the use of siliconeelastomers in medical device technology that they arealso suitable for use in contact with food. This is,

indeed, true. The reasons are in the compatibility ofsilicones with their environment, chemical resistance,physical and mechanical properties.

Table 17 provides an overview over food and relatedapplications. Silicone elastomers are used in manydifferent areas ranging from packaging aids or elementsto tubings for the food industry.

This section is somewhat related to Section 3.4, on theuse of silicone in contact with drinking water. However,here we concentrate on applications where siliconerubbers are directly in contact with foodstuffs.

Important baby care applications are included in thischapter as baby feeding equipment is one of the largerapplications for liquid silicone rubbers.

Silicone elastomers in contact with foodstuffs have tocomply with relevant legislation and regulations.

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Silicone Elastomers

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Perhaps the most famous regulations in that respectare the German BgVV Recommendation XV‘Silicones’ and the US Food and DrugAdministration (FDA) Regulation CFR21 Section177.2600. These contain positive lists of sanctionedingredients for rubber parts in contact with food.What is not listed must not be contained in thesilicone elastomer formulation. BgVV also regulatesthe amount of volatile matter in the siliconeelastomer. The weight loss of a silicone part mustnot exceed 0.5% after heat treatment for 4 hours at200 °C. Further, the two regulations prescribeacceptable levels of extractables, etc.

Silicone elastomers meet such requirements, if they areprocessed correctly and have undergone sufficient postcure. Post curing is used in order to finalisevulcanisation and strip off volatiles which are containedin the rubbers as cured. The loss of volatiles from asilicone elastomer during post cure is illustrated inFigure 4, using different thicknesses of samples anddifferent temperatures.

Further, post curing also helps to improve physical andchemical properties, such as the compression set. Thisis shown in Figure 5.

In the case of baby care applications, which were oncedominated by latex, silicone elastomers are becomingmore and more prevalent. This has to do with the factthat the curing systems of organic elastomers ofteninclude amines and other additives leading to potentialtoxic contaminants, such as nitrosamines.

On the other hand there are silicone rubbers/elastomerswhich are amine free and, in most cases, are platinumcured. Such curing systems allow for biocompatibility,as mentioned in the healthcare chapter. Correctlyprocessed parts do not show detectable nitrosaminelevels without and after proper post cure.

Other favourable properties of silicone elastomers forfood contact are sterilisability, steam, heat and chemicalresistance which makes them the perfect materials inbaking moulds, baking tray coatings and the like.Typically, silicone baking moulds are produced fromliquid silicone rubber or addition cured HTV.

The silicone rubber has the required heat and chemicalresistance. Well established companies specialising inconsumer goods and appliances have started to sellthese products including life time guarantees andspecial cooking advice.

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Silicone Elastomers

23

The food industry is using silicone elastomers fortubings and fittings. Perhaps one of the most interestingapplications in the rubber industry related to food ismilking equipment. Predominantly this area has beenoccupied by nitrile rubbers, which again use potentiallyunfavourable additives. In the last 5 years siliconeelastomers have begun to be substituted in thisapplication. The parts are limited to silicone tubing,milking teats and milk liners. Reportedly, they exhibita longer life time and are quasi inert with respect tomigratable substances in line with the regulations (againproper processing and post curing are a must).

3.9 Other

3.9.1 Safety Applications

The most valuable safety property is the fact thatsilicone elastomers do not burn easily. This means thattheir limiting oxygen index is always above 20% (a.5,a.6, a.7 and other standards related to flammability),and, burning tests, e.g., UL94 HB, are easily passed.Once a silicone burns the spread of the flame is slowand the combustion products are silica, CO, CO2 andwater, products with low toxicity.

Figure 4

Weight loss of ELASTOSIL® LR 3003/50 as a function of post curing time

Figure 5

Compression set (DIN 53517) as a function of post curing time and sample thickness forELASTOSIL® LR 3003/50

Sandra

Text Box

3.8 Food Sector

Sandra

Text Box

3.8 Food Sector

Silicone Elastomers

24

Unlike most organic elastomers, silicone will not onlyform such harmless combustion products, it will alsoproduce very little smoke and, hence, permit a gooddegree of visibility in the event of a fire.

Further, silicones are capable of forming a stable ash,which in extreme cases will turn into very hardceramic, as discussed under safety cable materials(Section 3.3).

The advantage of such an ash forming behaviour duringburning is also very useful in the case of door seals, orany kind of gasket that needs to have sealing propertiesat least against the spread of flames or smoke, as in thecase of two sections of a building, for instance.

Many of the recent and past accidents in buildings,aeroplanes, ships, etc., could have resulted in asignificantly lower number of victims if siliconeprofiles or cables had been used correctly.

3.9.2 Aerospace

Because of their resistance and relatively smallvariation of properties across a vast temperature range,silicone elastomers have occupied a substantial part ofthe market for aeronautic applications for rubberymaterials.

Phenyl methyl silicone elastomers retain lowtemperature flexibility in extreme conditions evendown to –110 °C.

The applications of silicone elastomers range fromadhesives in satellites and aeroplanes to componentsof wings, landing flaps, window gaskets, floorcomponents and many more parts.

It goes without saying that the other properties ofsilicone elastomers and rubbers such as heat and UVresistance, and the hydrophobic behaviour, contributeto their wide usage across these industries.

3.9.3 Building

New technologies for modern buildings have evolvedover the last 3 decades in the form of structural glazing.This building concept involves covering the fronts ofbuildings with glass panels.

The glass is held in place by applying adhesives,elastomeric profiles and rigid structural elements.

Over the past 5 years the building industry has alsoput i ts focus on design aspects. Functionalelastomeric profiles are no longer invisible.Moreover, they have become part of the designconcept of the buildings.

With such design requirements and the conditionsthat are imposed on large buildings, silicone hasbecome a good option for elastomeric profiles andsilicone adhesives are well established. This ismainly due to cold flexibility, almost indefinite UVstability and relatively low compression set.Needless to say, silicone rubber profiles are availablein any colour whereas all organic rubbers havecertain restrictions.

3.9.4 Pharmaceutical

Many pharmaceutical tubings, fittings, gaskets andthe like contain silicone rubber, because of its ‘inert’behaviour towards certain media and itsresterilisability.

3.9.5 Spin Casting

Silicone elastomers provide an economically idealsolution, for shaping metals with relatively lowmelting temperatures.

These alloys are cast into a rotating silicone disccontaining a certain number of cavities. Because ofthe heat stability of the silicone rubber the number ofcasting cycles is approximately 100-500 dependingon the metal and the size of the parts.

Silicone rubber has to exhibit an utmost degree ofheat and reversion stability. A specially designedsolid silicone rubber with a hardness of around 40Shore A is used as a raw material; it is mixed withground quartz in order to obtain the requiredhardness, catalysed with dicumyl peroxide. The mixis cut into discs, into which one imprints thenegative halves of the originals and the runnersystem. The discs are cured at >160 °C and are thenready for use.

This technology is related to mould making as onemakes multiple copies out of an original.

Silicone Elastomers

25

4 Composition and Function ofSilicone Elastomers

4.1 Introduction and Classifications

All silicone elastomers consist of crosslinkedpolydimethyl siloxane (PDMS) molecules, fillers andadditives.

Tentatively, apart from the curing temperature, thedifferences between RTV, HTV and LR are themolecular mass of the raw materials, as indicated inTable 18.

Similar amounts of fillers are used in general. Allsilicone elastomers typically contain between 0% and40% fillers. The bulk of this is fumed silica with surfaceareas between 150 and 300 m2/g. Fillers are responsiblefor the mechanical and flow properties.

So-called inactive fillers do not reinforce the elasticsilicone network. They are widely used in order to improvecertain chemical or thermal properties. Examples of suchfillers are ground quartz, diatomaceous earth and chalk.Too high levels of such inactive fillers result in loss of theexcellent mechanical properties of most siliconeelastomers. However, loads of up to 100 parts per 100parts rubber are occasionally used in order to make thesilicone compound cheaper. This latter degree of fillingis not advisable, as the resulting compounds behave morelike elastic rocks than elastomers.

It goes without saying that a high degree of filling resultsin very high densities and thus a high weight per part.

4.2 Properties of Silicone Elastomers

The generally advantageous properties of siliconeelastomers are as follows:

• flexible in the cold down to –40 °C, in special,extreme cases –55 °C

• heat stable almost indefinitely up to 180 °C in hotair, with special additives up to 250 °C and for ashort term even to 350 °C!

• transparent: also addition curing grades withoutyellowing

• compliant with food regulations such as BgVV,FDA, etc.

• sterilisable by gamma irradiation, steam andethylene oxide

• very low compression set at elevated temperatures

• low flammability, non toxic combustion products

• unique electrical insulating properties, highdielectric strength >20 kV/mm (1 mm test slab),high volume resistivity of approximately 1015 Ωcm

• high durability

• good mechanical properties

• unlimited pigmentability, etc.

Most silicone elastomers possess these generalproperties. Their most unique property, however, is thecomparatively constant elastic properties between-40 °C and +180 °C. No other organic or inorganicelastomer is capable of maintaining its properties oversuch a wide temperature range, except forfluoroelastomers, which seem to have comparablestability in terms of working temperature.

Table 19 shows some of the mechanical properties ofa typical HTV elastomer for various temperatures.

Table 20 gives a rough comparison between theperformance of silicone elastomers and some otherrubbers. Table 21 gives a comparison of the propertiesat different temperatures of EPDM, a silicone elastomerand a natural rubber (NR).

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26

4.3 Chemistry and Curing Mechanisms ofSilicone Elastomers

Silicones and silicone elastomers originate from 'sand'.Even though this is not as simple as it sounds, thecomplex chemistry and versatile properties of siliconesare ‘built on sand’, as shown in Figure 6.

Figure 7 shows a schematic overview of the processingand product groups for silicone elastomers.

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Silicone Elastomers

27

5 Room Temperature VulcanisingSilicone Elastomers

5.1 General

Many RTV systems are widely used as siliconesealants or adhesives. However, their individualfunction is not typical of the application of siliconeelastomers. It is more related to sealants used instructural glazing and in the building industry. Insilicone elastomer technology these systems are used

for joining silicone profiles and moulded parts. Theapplications of such adhesives range from buildingto healthcare and from automotive to aerospace.However, these materials are excluded fromdiscussion in this review as this would be beyond itsintended scope.

RTVs with clear elastomeric functions are materialsthat act as static or dynamic parts, e.g., gaskets,prototypes and mould making aids. RTVs are also usedto produce moulded parts, e.g., electrical insulators formedium and high voltage.

Figure 6

Schematic of the production of silicone elastomers

Figure 7

Products and processing technology for silicone elastomers

Silicone Elastomers

28

5.2 Condensation Curing RTVs

In most cases RTV systems are condensation curing.The curable composition is formed by mixing twocomponents, or in the case of one component systems(RTV-1) it is ready to use and it will cure after itsapplication out of the packaging. The major part of thecuring system is a PDMS (polydimethyl siloxane)polymer with terminal hydroxyl groups and areinforcing filler. As additives it contains a crosslinker,usually a functional silane, and a catalyst, in many casesa tin complex.

The curing systems are classified by the chemicalnature of the split products formed during thecondensation process, when the functional silane isincorporated into the polymer network splitting off thecondensation products.

Table 22 shows examples of the current mostfrequently used curing systems, classified accordingto their acidity – acidic, neutral or basic.

Such systems cure in the presence of air moisture. Asthey form split products during their cure, such materialsexhibit shrinkage with increasing degree of curing.

The characteristics of a condensation curing system are:

• The reaction is isothermal.

• The volatile alcohol, oxime, amine, etc., is formedas a condensation product.

• A mass loss occurs due to the volatilisation of thesplit product, e.g. alcohol, which results in a‘chemical’ shrinkage of the cured rubber in therange of 0.2-2 % (linear), depending on theconcentration of reactive groups.

• In most systems the curing reaction reverts attemperatures exceeding 90 °C if the reaction isincomplete.

• Retardation of cure occurs if there is a lack ofmoisture in the rubber or the ambient atmosphere.

The mechanism of condensation curing is illustratedin Figure 8. In this curing process a silicone polymerwith terminal hydroxyl groups reacts with a crosslinkerwith at least 3 alkoxy, carboxyl, amino or oxime groupsin the presence of moisture. Organotin complexes actas catalysts.

5.3 RTV-1 for CIPG and FIPG

RTV-1 systems often find applications as gaskets. Thegasket technology is termed Formed-In-Place-Gasket(FIPG) and Cured-In-Place-Gasket (CIPG). Mosttypically RTV-1 systems are used as FIPG materials.They are used in automotive applications in order toseal engine segments such as the lubricating andcooling regions of the engine.

The rheology of these RTV-1 sealants allows for fullyautomatic application with a low degree of waste,simple substrate treatment and design.

Once cured, the CIPG gaskets stick to the substratesand allow for good protection against loss.

In FIPG technology the gasket cures after joining thetwo parts (e.g., flanges) that are to be sealed off. Thisallows for quite low requirements in respect ofdimensions as the sealant adapts itself to the spacebetween the two parts. No special surface treatment ofthe flanges is required.

The use of material is economic. Correctly appliedFIPGs help to avoid leakages which could result frominserted gaskets or CIPGs.

Table 23 shows the properties achievable with RTV-1CIPG materials, which are commonly used inautomotive and other high performance applications.This serves as an example of media and heat resistance.

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Silicone Elastomers

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CIPG and FIPG techniques are also used across otherareas, for example in steam iron gaskets. Therequirements are similar to those of the automotive areas.

5.4 RTV-1 for Baking Tray Coatings

These RTV-1 systems are applied by spraying, theirrheology is adjusted to give a low viscosity. Typically,one would use acetoxy systems, such as the exampledescribed in Table 24. Baking trays are used at elevatedtemperatures. The RTV coating acts as a heat stablerelease agent. (Silicone oils and emulsions are also usedas release agents in the tyre industry.)

5.5 Adhesive RTV-1 Materials

This area is somewhat related to FIPG/CIPG. FIPGsealing techniques can also be used as adhesivetechnology in various application areas.

Acetoxy systems are widely used as so-calledgeneral purpose adhesives. Table 25 provides arough overview of RTV-1 adhesive or coatingsystems to illustrate the variety of properties andproducts.

As indicated in this table viscosities range from 500mPas up to several 100,000 mPas, the latter in thecase of non sag materials.

Non sag materials are required in order to fill widergaps or to allow for the application of a cord orprofile shape onto a substrate, the shape of which isstable before and during the cure.

Low viscosity adhesives are desired if the processorneeds an easily spreading or a sprayable material.

Figure 8

Reaction mechanism of the condensation curing process of RTV-1 or RTV-2 systems

Silicone Elastomers

30

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5.6 Condensation Curing RTV-2 Systems

To obtain stable systems, it is imperative to split up therubber constituents into two components in such a waythat unwanted reactions will not occur during their storage.

Condensation-curing rubbers consist of a rubber baseand a curing agent (hardener, catalyst).

Polymers, fillers, softeners and some additives arenormally contained in the rubber base, whilstcrosslinkers and tin catalysts, as well as extenders anddyes or pigments (if added for visual mixing control),are comprised in the curing agent.

Even though condensation curing systems seem to beoutdated they are still a widely considered option. Forexample, the curing reaction is hardly inhibited by

pollutants from the environment, as would be the casewith addition curing materials.

5.7 Mould Making Condensation CuringRTV-2 Materials

One of the main applications of 2-component RTVsystems is mould making. The curing agent is a liquid orpaste which is incorporated into the mould making base.Once mixed the system will cure, if enough moisture ispresent in the ambient air or the mix itself. The preferredcuring system is alkoxy based, i.e., the split product is analcohol.

Table 26 provides us with an overview on commonlyused mould making RTV materials and their properties.It can be quite difficult to pick the right material for a

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3054M elbaruoP tfos, 000,04 52 0.5 053 02> 5.0

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noitiddAB/A0064M elbaruoP tfos, 000,51 02 0.7 008 02> 1.0<

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noitiddAB/A2464M elbaruoP drah, 000,51 73 0.7 055 03> 1.0<

Silicone Elastomers

32

given application. This is why mould makers rely onselection guides and technical service as provided byraw material suppliers.

5.7.1 Speciality Mould Making RTV-2 Materials

Material selection essentially depends on the mouldingtechnique, the geometry to be duplicated (undercuts,etc.), the required chemical resistance and mechanicalproperties of the silicone material.

Table 27 provides an overview of speciality materialsand their properties. In most cases copies are beingmade of other pourable systems, which are eitherchemically aggressive or hot, etc.

The heat stabilised materials of Table 27 are also heatconductive, which allows the replica to cool off morequickly.

5.8 Condensation Curing RTV-2 Compoundsfor Encapsulation

These materials are used for encapsulation ofelectric or electronic components. They have lowviscosities (900-10,000 mPas) with good dielectric,i.e., insulating properties, as summarised in Table28. They require between 2% and 10% catalyst/hardener.

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Silicone Elastomers

33

5.9 Adhesives and Sealants Based onCondensation Curing RTV-2 Compounds

Condensation curing RTV-2 adhesives are less commonthan addition cured adhesives. This has to do with thefact that there are numerous RTV-1 systems with a goodprocessing time.

They are used in FIPG technology, in particular whereinhibition (e.g., by amines, sulfides or organic acids)limits the use of Pt-curing technology (Table 29).

5.10 Addition Curing RTV-2 Systems

Such systems are mainly two component materials,because the reactive constituents, which allow curingat room temperature with no split products and noexternal reactant (such as air moisture as mentioned incondensation curing) need to be kept separate.

Most common addition curing RTV systems areavailable in mixing ratios of 1:1, 9:1 or 100:1. Variablemixing ratios are possible.

Usually the reaction is very fast, once the twocomponents are mixed. The processor has to use themixture within a certain time period. This time is calledpot life. Once pot life has expired it is no longer possibleto process these materials correctly.

As the curing reaction is not accompanied by theformation of any split products addition curedelastomers do not exhibit shrinkage upon curing, whichleads to easy control of shapes and dimensions.Furthermore such systems are practically odourless.The principle of the addition reaction is shown inFigure 9. The same mechanism is typical for additioncured LR and HTV compounds.

The curable composition contains polydimethylsiloxane polymers with terminal and/or non terminalvinyl groups. As a crosslinker a polydimethylsiloxane polymer with Si-H groups is added. Thesystem starts to cure, once a platinum compound isadded as a catalyst. An inhibitor regulates the rateof the curing reaction.

Such compositions often contain a reinforcing filler,e.g., fumed silica with surface areas of 100 to400 m2/g, allowing for good mechanical propertiesof the cured mixture.

As indicated in Tables 26 and 27 addition curedsystems exhibit a number of advantages in mouldmaking. One would expect that these advantages arealso present in the case of encapsulating, potting oradhesive RTV-2 systems.

This is the case because such materials are widelyused in industrial mass production, where cycle times(i.e., times to produce one unit) and precisedimensions are a must. The latter is better met withaddition curing materials as they do not shrink uponcure, whereas substantial shrinkage is found usingcondensation curing materials. A clear plus is theabsence of split products as formed in the curingprocess of condensation cured materials (andperoxide cured HTV, as described later).

A disadvantage is the possibility of cure inhibition,if amines, sulfurous or other catalyst poisonsdeactivate the Pt catalyst.

Viscosity values range from well below 10 Pas to50 Pas and above. Above 10 Pas the mechanicalproperties such as tear resistance, tensile strengthand elongation at break are quite good, whereas thesevalues are less at very low viscosities.

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Silicone Elastomers

34

RTV-2 systems with high viscosity (50 Pas) can bedesigned as sponge formulations with moderatemechanical properties.

5.11 Silicone Gels

Silicone gels are addition curing RTV-2 systems, uponcuring they form an elastomeric network with a gel-like consistency. By varying the mixing ratio it ispossible to adjust the consistency of the gel from nearlyliquid to hard.

As these gels tend to be very soft, their hardness is notmeasured in Shore A units but using the penetration

method. This hardness measurement involves a conewhich is immersed into the gel. The depth of thispenetration is recorded, and it provides the value forthe hardness of the gel.

Silicone gels are widely used in healthcare, electronicsand automotive areas. Applications range fromdamping gels in sporting goods, operation pads andencapsulated electronic components such as integratedcircuits to rain sensors, etc.

While allowing for a wide range of hardness, themechanical strength of the gels is very poor. Theirtransparency, however, is excellent because of theabsence or very low content of filler(s).

O Si

CH3

CH3

CH = CH2 + H Pt catalyst

Si

CH3

CH3

CH2

Si

O

O

CH3

Crosslinker

Polymer chain end

SiH3C H + H2C = CH

O

Si

CH3

CH3

O

O CH2 Si

O

O

CH3

SiH3C CH2

O

CH2 Si

CH3

CH3

O

Rubber

Figure 9

Reaction mechanism of addition curing RTV-2 silicone rubber systems

Silicone Elastomers

35

5.12 Addition Curing Systems for Mould Making

While processing and properties are roughly the sameas with condensation curing materials, mould makingwith addition curing systems has vast advantages.Tables 26 and 27 have illustrated the characteristics ofaddition curing RTV-2 systems.

It goes without saying that these advantages ordifferences compared to condensation curing systemsare also of importance when it comes to applicationsin automotive, aerospace and household applications.Table 30 shows the fundamental differences betweenthe two curing systems.

5.13 Addition Cured RTV-2 Systems forEncapsulation

These materials range from very low viscosity withstandard silicone properties, medium hardness forgeneral purpose applications, to very high density andthus heat conductivity for special encapsulationprojects. Most of these materials are mixed in the ratio9:1, where the small component has a much lowerviscosity than the large one.

Table 31 shows examples of a number of widely usedRTV-2 encapsulating materials.

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Silicone Elastomers

36

5.14 Addition Cured RTV-2 Adhesives andSealants

Low viscosity is no longer desirable in the case ofadhesives. They should exhibit a certain rheologicalbehaviour allowing for their proper application onto thesubstrate(s) that have to be glued together. Theseadhesives are called RTV-2 systems for historic reasons,as they are actually high temperature curing.Characteristic curing times range from 5 minutes at 150°C to 1 minute at 200 °C, the latter also allowing for asubstantial pot life at room temperature. Table 32 showssome properties of silicone adhesives. One componentmaterials are marked 1K. Non sag adhesives are alsosuitable for FIPG and CIPG technology.

5.15 Addition Cured RTV-2 Foam forCompressible Gaskets

The latest generation in gasket materials are silicone foamswhich were derived from RTV technology. The processorsaim for silicone properties and, at the same time, for weightreduction and/or for low heat conductivity.

These foams can be used in multi-purposeapplications, and, they can be applied in sheets, stripsor cords, all of which are fairly easy to produce,allowing for a very uniform and closed cell structure.

These foam compositions allow the production ofsoft gaskets which are compressible. In siliconeelastomer gasket technology this is a breakthroughas even the softest sil icone gel is nearlyincompressible.

Addition cured silicone foams have to develop a gasas they start to cure. This is usually hydrogen,developing from a second reaction of the silicon-hydrogen groups which take part in thehydrosilylation crosslinking process. This reactiontakes place in the presence of hydroxyl groups whichare present in the formulation.

As in other RTV-2 systems the foams are designedto be self levelling or non sag, the latter allowingfor use in Formed-In-Place-Foamed-Gasket (FIPFG)technology.

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Silicone Elastomers

37

The applications are in all areas such as automotive,aerospace (seat components), building industry (flameretardant cable bushings) and mouldings, using selflevelling foams that are poured into moulds of therequired shape.

The mixing ratios are 1:1 and variable in many cases.The foam densities are as low as 300 kg/m3, or lowerin special cases as shown in Table 33.

As these materials develop some amounts of hydrogenduring the processing, sufficient ventilation must besupplied for safety reasons.

In order to apply foams such that they stick to surfaces,one has to use silicone primers in the same way as withconventional techniques for silicone rubber bonding.

6 Liquid Silicone Rubber

6.1 General

All liquid silicone rubbers are addition curing. Theycure at elevated temperatures and their main use is insilicone mouldings produced by injection moulding,and textile coatings.

The scope for application of liquid silicone rubbers ishuge (a.8) (49). In injection moulding they are used

where large series need to be produced and the costper piece is a big issue.

To a certain extent their use is highly competitiveagainst RTV and HTV solid silicone rubber, even incase of applications in the transmission anddistribution industry, such as medium and high voltagecable accessories and smaller insulators. This is dueto the short curing time and available processingtechnology, allowing for an utmost degree ofautomation and almost waste free production.

6.2 Curing Mechanism of Liquid SiliconeRubbers

The curing mechanism is the same as for the additionRTV-2 systems (see Figure 9). The mixing ratios ofthe single components vary from 1:1 to 100:1 in thecase of RTV-2, whereas liquid rubbers are mosttypically 1:1 systems. The difference in thecompositions is such that the catalyst (A component;Pt-complex) and inhibitor levels (A and B components;alkyne alcohol) are set in order to provide virtually nocuring at room temperature, and high speed of curingat elevated temperatures (for example, when the coldmaterial hits the hot walls of the mould during theinjection moulding process).

Figures 10, 11 and 12 demonstrate the curingcharacteristics for liquid silicone rubber.

Figure 10

Non isothermal curing characteristics of an addition-cured LR and a peroxide-cured HTV silicone(linear scan at 10 °C/min)

Silicone Elastomers

38

Please note that a noticeable degree of curing onlyoccurs after 70-100 hours from mixing A and B at roomtemperature. This time changes to ‘indefinitely’ at–20 °C and ‘seconds’ at 180 °C, respectively.

6.3 Standard Liquid Silicone Rubbers

Standard liquid silicone rubbers originate from generalrequirements that have evolved from the markets forsilicone elastomers over the past 25-30 years. Theseproducts are also known as general purpose LR.

Liquid silicone rubbers have been on the market for30 years with annual growth rates of +10% and higher.Such materials have undergone several innovativechanges, especially over the past 10 years. Thesechanges relate to specifications and curing speeds, etc.

The purpose of new fast curing materials compared tostandard grades is to reduce the cost per piece, whichresults from shorter cycle times during processing.These liquid rubbers not only have the samespecification but also they are chemically identical totheir older predecessors after post cure. Table 34 shows

Figure 11

Isothermal curing characteristics of a LR. Curing times of ELASTOSIL® LR 3003/50 at different temperatures.

Figure 12

Pot life of a LR as a function of temperature. Viscosity of the AB mixture of ELASTOSIL® LR 3003/50 as afunction of time and temperature (Brookfield viscometer)

Silicone Elastomers

39

examples of the materials available comparing fast cureand standard grades of LR. Fast curing technologyallows the processor to choose a lower mouldingtemperature to achieve the same or still shorter cyclesas with a standard material. This is emphasised by thebold letters in the table. Fast curing LR compositionsalso provide a new and very interesting possibility,comoulding with thermoplastics.

Standard LRs are specified by original equipmentmanufacturers in automotive, healthcare and domesticappliances.

The typical hardness range for standard liquid siliconerubbers is between 10 and 80 Shore A.

6.4 Speciality LRs

6.4.1 High Tear LR

High tear resistant LRs were initially developed in orderto provide maximal mechanical strength to baby soothersand baby bottle nipples. Today’s global market for suchapplications is easily beyond 1,000 tonnes per year, andit is characterised by significant growth as a replacement

for latex products, which possibly still account for morethan 60% of elastomeric baby feeding applications.

High tear LR is continuously being used to substitutesolid silicone offsets and also organic rubbers. Most ofthese substitutable materials have quite highmechanical strength which is of importance either inthe application, for material approval by originalequipment manufacturers (OEMs), and/or duringprocessing such as demoulding or assembly, etc.

Table 35 shows a comparison between the tearresistance of high tear LR and HTV (a general purposeHTV would be similar to standard LR) (a.9).

6.4.2 No Post Cure LR

Standard liquid rubbers allow for a relatively lowcompression set. This is achievable only after post cure.Compression sets as low as 10% or even lower arepossible. Without post curing such materials will havea compression set of 70%.

As the process of post curing is energy intensive andsubstantial lowering of the compression set is usuallyachieved after 6 hours at 200 °C consuming up to 125

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Silicone Elastomers

40

l/kg silicone/min of fresh air, many new liquid rubbersare being formulated to allow for a low compressionset even without post cure. These are denoted as NPC.The test method is DIN 53517, 22 h at 175 °C. Table36 gives a comparison between various grades and theirpost cured (PC) and no post cure (NPC) compressionset (CS). The most common values are shown as arange. See also Figure 5 on compression set.

The table is complemented by values for HTV rubbers.

Typically, post curing must be applied in all medicaland food contact applications.

NPC materials are thus limited to technicalapplications. Most technical liquid rubbers includeNPC technology as part of their formulation.

6.4.3 Heat Stabilised LR

In many automotive applications it is necessary to useLRs which are heat stabilised. Often, this can beachieved by colouring the rubber with a metal oxidecontaining pigment paste.

As per requirements from suppliers of ignition systems,new grades of LR were developed which are readilystabilised, black and do not require post cure (NPC).They are commonly used in spark plug boots.

Table 37 provides a rough comparison between an 80Shore A hard LR, both stabilised and without additives.A carbon black pigment paste has been used as astabiliser. Changing to lower hardness, heat stability getsbetter, the optimum being between 50 and 60 Shore A.

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Silicone Elastomers

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6.4.4 Coolant Resistant LR (NPC)

Gaskets for radiators in automobiles are a developingapplication for LRs.

The requirement is to have a gasket of rubber with aslittle change in properties over time as possible. Therubber gasket has to withstand coolants, usuallymonoethylene glycol (MEG) in water, at temperaturesof above 100 °C and a hot air environment at the outerside of the radiator. Further, the gasket must notembrittle at low temperatures.

Traditionally such gaskets have been made of EPDMrubbers. EPDM has better mechanical properties andcoolant resistance than silicone elastomers. However,coolant resistant silicone rubbers show the lowestrelative change in compression set in hot air and muchsmaller relative change in other parameters as shownin Table 38.

Such coolant resistant LRs can be used in a number ofdifferent, non automotive applications, because theyhave an increased chemical resistance in general.

6.4.5 Self Lubricating LR (NPC)

Such rubbers are also called oil bleeding or oil exudingmaterials. They are similar in appearance to standardsilicones once moulded. After some time they start toform an oily film on the surface of the parts.

They are most commonly used in the manufacture ofgaskets for electric connectors. The oil film serves asan aid during assembly, and, it improves thehydrophobic behaviour of the seal (this is why the namefor the assembled connectors is ‘weather pack’).

Typically the oil content ranges between 2% and 7%and the speed and amount of oil bleeding correspondsto these contents.

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Silicone Elastomers

42

The oil (also known as bleed fluid, etc.) is a phenylpolydimethyl siloxane. Because of the content ofphenyl groups this oil is not compatible with thematrix of the silicone rubber. As a consequence itmigrates freely through the elastomeric networkresulting in the formation of an oil film on the surfaceof the parts (15).

6.4.6 Oil Resistant LR (NPC)

Silicone elastomers and in particular siliconerubbers, both solid and liquid have relatively poorresistance when in contact with apolar media suchas engine oils and the like.

However, it has been possible to formulate liquidsilicone rubbers with increased oil resistance.

Oil resistance typically is measured at 150 °C for72 hours. The changes in hardness and mechanicalproperties again should be as small as possible overtime. In addition, because of the apolar character ofthe silicone network and the apolar composition ofengine oils the rubber absorbs part of the oil whichcauses it to swell. The increase in volume should beas small as possible.

The older formulations for oil resistant liquid rubberscontain a passive filler and certain additives. Thefiller, however, eventually causes problems in mouldtechnology and machinery as it is strongly abrasive.

The latest technology allows for non abrasive liquidsilicone rubbers with the same oil resistance. Table39 shows a comparison between standard liquidrubbers and oil resistant LR, both abrasive and nonabrasive.

6.4.7 Self Adhesive LR

6.4.7.1 Self Adhesive LR for Technical Applications

Self adhesive LRs have been known in the marketfor some years. However, the name self adhesiveindicates that it could be tough to make it stick wheredesired and yet easy to demould at the same time.Processors helped themselves by teflonising mouldsurfaces when processing self adhesive liquidrubbers.

The advantage for the processor of self adhesivetechnology clearly is the simplicity of combining plasticwith silicone elastomers without using a primer.

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Silicone Elastomers

43

The latest, very exciting developments allow thesilicone rubber processors to injection mould selfadhesive LRs onto substrates with good adhesion.At the same time these materials are easy to demouldwithout the need of release coatings such as teflon(the latter has to be renewed from time to timeresulting in undesirable shut downs; also teflonimpairs the heat transfer). Adhesion builds up on atime scale which is usually much longer than themoulding cycle alone, as shown in Figure 13. Thisfigure also provides an explanation as to why thisnew self adhesive material would not adhere to themould surface.

Table 40 shows a compilation of substrates to whichadhesion is possible. With great pleasure the author wouldalso like to point out that it is possible to achieve adhesionon steel inserts without causing problems in demoulding.

The only restriction about self adhesive technology isthe fact that it is only suitable for technical applications.This has to do with non compliance with the BgVVand FDA (regulations for food contact and medicalmaterials), both of which require post cure in order toreach the prescribed volatile and extractable levels. Apost cure at 200 °C over several hours will destroy orat least seriously affect the plastic substrate.

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Silicone Elastomers

44

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Silicone Elastomers

45

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Silicone Elastomers

46

6.4.7.2 Self Adhesive LR in Food and RelatedApplications

The latter facts led to the development of a self adhesiveLR which is suitable for contact with food after postcure. However, this would still harm the plasticsubstrate, although some plastics withstand a post cureat 200 °C, such as PBT.

This recently developed LR adheres well to some PBTgrades (e.g., PBT Pocan B 3235 of Bayer, PBT UltradurB4300G6 of BASF).

Further, it shows a stronger adhesion to other substratesthan with standard silicones.

It would go beyond the scope of this article to go intofurther detail on self adhesive liquid rubbers. For furtherinformation refer to Rapra’s Handbook of RubberBonding containing an interesting review on thebonding of silicone rubber, or contact the raw materialsupplier (a.11).

6.4.8 Electrically Conductive (AntistaticSilicone!) LR

It is quite remarkable that it is also possible to formulatean electrically conductive LR out of one of the bestelastomeric insulators.

If a liquid rubber is filled with substantial amounts ofcarbon black its volume resistivity drops from 1015 Ωcmdown to below 12 Ωcm. This is accompanied by a strongincrease in viscosity, which rises from approximately1,000 Pas to 8,000 Pas at a shear rate of 1 s-1 (cone plateviscometer).

By varying the amount of carbon black, the siliconesupplier is able to provide electrically conductiverubbers in a range of conductivities, as shown inTable 41. Note that the viscosity increases with higher

conductivities. This has to do with the load of carbonblack, which is used to make the silicone rubberconductive. The same conductivities can be realisedwith HTV rubbers.

The use is various, it ranges from conductive pills inelectronic keypads (standard silicone keypad withconductive pills stuck onto it) to so-called stress conesor deflectors in transmission and distribution (T&D)industries. The latter being an application for mediumvolume resistivities.

Unfortunately, because of the nature of carbon black,it is not possible to achieve resistivities which wouldjust provide antistatic behaviour without making thesilicone a good conductor, viz. applying it in volumeresistivities of approximately 1,000 to 5,000 Ωcm. Thisrange is not achievable on a basis which is accurateenough to make antistatic parts, this is due to the factthat resistivity rapidly increases by approximately 5 to8 decades in a narrow range of concentrations (similarto a step function).

6.4.9 Flame Retardant LR

Many consumer electronics contain silicone rubber. Inmost cases standard silicone rubbers are satisfactorywith respect to their flammability.

However, if it comes to high voltage areas such as TVtubes and the like, the requirements for flameretardancy are raised. This means that the materialsmust have a limiting oxygen index of at least 27% anda UL94 rating of V0.

Table 42 shows the differences between standard LRand flame retardant LR.

As mentioned in the applications sections, such rubbersfind their applications in anode caps.

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Silicone Elastomers

47

6.4.10 Extra Liquid Rubber (XLR®)

In some applications such as in transmission anddistribution or for the manufacture of parts with shotweights of several kilograms, it would be necessaryto use injection moulding machines with extremelyhigh clamping force.

Parts of this size not only exhibit very long fillingtime during injection but also high internal pressureduring the cure (the pressure is a consequence of thethermal expansion of the liquid rubber). Further, thecuring times are very long and can easily reach 30minutes to hours.

These difficulties led to the development of extraliquid rubber (XLR®). This material has an extremelylow viscosity allowing for a quicker filling step. Alsothis viscosity allows it to be used in a simple mouldwhich does not require an injection mouldingmachine. The typical mould temperature generally liesbetween 100 °C and 130 °C in this latter case.

The viscosity is down to 100 Pas compared to 500 Pasin the case of a standard LR.

6.4.11 Other Types of LR

It goes without saying, that, at least in theory, onecould combine the LR technologies in order toformulate new compositions. This is possible, e.g.,in the case of self adhesive silicone rubbers. Examplesare: self adhesive, oil resistant LR; and self adhesive,oil bleeding LR.

6.5 Pigment Pastes

Another advantage of silicone elastomers is theirpigmentability. Suppliers have a range of pigmentpastes permitting almost any colour. The user has tomix these pastes in certain ratios in order to obtainthe desired colour. This mix is then added to thesilicone rubber via the colour line of the injectionmoulding machine.

The pastes deep black, ivory and red iron oxide alsoact as heat stabilisers.

Such pastes essentially contain a vinyl siliconepolymer and the pigment. We have already shown thestabilising effect of pigment pastes.

It is highly advisable to the processor to use LR andpigment paste from the same supplier where possible.Then the system is stable, whereas in the opposite casethe pigment paste could affect the performance of the LR.

7 Solid Silicone Rubber

7.1 General

The consistency of solid silicone rubber is reminiscentof plastilline. Hence, its viscosity is lower than that oforganic rubbers. This consistency is such that it ispossible to supply solid silicone in almost any shape.

The available geometries range from simple strips (asthey come off the two roll mill), cords, coils, blocksand profiles to pellets.

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Silicone Elastomers

48

In terms of chemistry there is a major difference betweenRTV and LR. In the first place there is the much higherviscosity. Consequently the molar mass of the polymerswhich form the elastic network is much higher.

Because of this high molar mass, cured HTV usuallyhas a lower crosslink density or at least a differentnetwork structure than RTV or LR and thus much bettermechanical properties.

This mainly holds for peroxide cured HTV rather thanfor addition cured HTV, the latter exhibiting very highmechanical strength but relatively poor recoveryproperties (which can often prove to be advantageous).

Curing mechanisms are restricted to peroxide (Section7.2.2) and addition cure.

No condensation cure is known for HTV silicone rubber.

7.2 Curing Mechanisms of Solid SiliconeRubbers

7.2.1 Addition Cure

Please refer to Figure 9 in Section 5.10. What is verymuch different with addition curing HTV is the factthat it is available both as a one component system,yet exhibiting a considerable life time, and a twocomponent system.

The one component system represents the mostspectacular recent development available on thesilicone market.

Unlike LR, these systems are stable between 2 monthsand even up to 12 months, both at room temperature.

The 2 month system is used for extrusion, the 12 monthsystem is used for moulding.

Because of some uncertainties during transportationof such uncured rubbers to the processors, the providerwill not guarantee any longer than 2 or 3 months aftershipment.

In the second case, the two component system, theprocessor will get two separate components which havea considerably longer shelf life. The mixing ratios rangebetween 1:1 and 100:1.5. For the first mixing ratio,component A again contains the Pt catalyst and B thecrosslinker and inhibitor(s), the latter being the sameas used in LR.

In case of the 100:1.5 system the components are abase and the catalyst. The small component containsPt whereas the large one consists of HTV rubber base,crosslinker and inhibitors.

The life time of the two components as mixed rangesbetween 6 hours (for 1:1 extrusion), over 24-48 hours(for 100:1.5 for extrusion), to more than 1 week (for1:1 moulding).

To date processors seem to prefer 1:1 systems.However, in order to become competitive, such systemswill in future be substituted for 100:1.5 or onecomponent systems because of economic advantagesand increased flexibility.

Currently the preferred curing system is peroxidecuring HTV, which is described below. To dateprocessors seem to prefer such systems for variousreasons including price. The disadvantages of peroxidecured HTVs are:

- Yellowing after post cure,

- Smell in production,

- Peroxide residues in the rubber,

- Regulatory issues (in case of extrudable HTV),

- Surface with very high friction coefficient (so-called surface stickiness),

- Smell and taste issues, and

- Peroxide split products in the atmosphere.

Therefore the future of solid silicone rubber is inaddition curing technology. Its advantages arenumerous and compelling. Today most pharmaceuticalapplications have switched to the use of addition curetechnology, with the following benefits:

- No yellowing, even after post cure,

- Smell free, cleaner production,

- Very dry surface,

- Easy to demould, no air inhibition,

- High transparency,

- High tear and tensile strength,

- No post cure necessary, and

- No peroxide split products or remainders in the rubber.

Silicone Elastomers

49

The fact that it is possible to pelletise solid siliconerubber opens up a very wide spectrum of possibilitiesfor automation (which also holds for peroxide curedsystems).

Another beauty of addition cured technology is theabsence of peroxide split products. Hence, a post cureis not necessary for many applications. However, thelatter is obligatory if one wants to reach compliancewith FDA, BgVV, or to produce cured goods to go intomedical devices.

7.2.2 Peroxide Cure

The most commonly used peroxides are shown, byapplication, in Table 43.

The function of the peroxides is the same. Theseperoxides are chemically stable at room temperature.At elevated temperatures their molecules split andprovide radicals which cure the silicone rubber.

The different chemical structures of the three peroxidesdetermine their use. C1 and C6 split at relatively high

temperatures (C1 at 155 °C and C6 at 160 °C).Therefore they allow the filling of the mould beforecuring. They are not suitable for extrusion because theyreact with ambient air at elevated temperature ratherthan with the vinyl groups of the silicone rubber. Thisbehaviour is also called air inhibition.

Crosslinker E is suitable for extrusion. It splits at>90 °C, and it has a very minute tendency to airinhibition. It is less vinyl specific than C1 or C6.Therefore it is possible to cure a HTV rubber, thepolymer of which is pure polydimethyl siloxane.

A post cure is needed after the initial cure duringextrusion or moulding, if one wants to reachcompliance with FDA, BgVV, or to meet medicaldevice specifications, or obtain smell free products witha low content of volatiles.

7.3 Standard Solid Silicone Rubbers

Standard HTVs are peroxide curing general purposegrades. They originate from the very first HTV gradesthat were provided to the silicone elastomer markets.

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Silicone Elastomers

50

However, their spectrum of properties and productionroutes have been modernised gradually over the past30 years. Also, the number of available products hasincreased to a much wider range of hardness.

General purpose rubbers usually are essentially suitablefor moulding and extrusion.

All general purpose materials are transparent. Manyof them are suitable for applications across all industriesincluding healthcare.

Table 44 shows a rough summary of standard solidsilicone rubbers (HTV) and their features.

The typical tolerance from lot to lot for the hardness ofHTV silicone rubbers is +/- 5 points Shore A.

There are other novelty or speciality HTV productgrades. It is difficult to describe the scope of theserubbers to the full. One section here is also dedicatedexclusively to addition curing HTV.

7.4 Speciality HTV (all peroxide)

7.4.1 High Tear HTV

High tear solid silicone rubbers HTV have a hardnessrange of 30-70 Shore A. Their tear strength is muchhigher than that of standard grades with a range ofvalues of 40-50 N/mm (ASTM 624 B).

These products exhibit slightly lower heat resistancethan general purpose rubbers. Also, their use is inmoulding, preferably.

It should be noted that it is virtually impossible to havehigh tear strength at a hardness higher than 72 ShoreA. Above this hardness, tear strength will drop toapproximately 20-22 N/mm.

7.4.2 Economy High Tear HTV

Such grades have been developed to cope with therequirements for medium to high tear strength. Theirperformance is somewhat between standard and hightear HTV. Their main advantage is a high performancemechanical spectrum coupled with cost savings relativeto high tear strength products.

The tear resistance of such products lies typicallybetween 30 and 40 N/mm (ELASTOSIL® 411/60).

7.4.3 Extrusion HTV

Special technologies are used to provide enough greenstrength to allow for the extrusion of large siliconerubber profiles. This is specially the case in tubingwith large diameters, or building profiles. Please alsorefer to the section on calendering (8.3.6).

The main hardness ranges between 60 and 75 ShoreA. It is interesting that these products also exhibitadvanced mechanical properties in line with theexcellent extrusion properties. However, they are lesssuitable for moulding.

7.4.4 Cable HTV

This is very much related to extrudable HTV. Thetypical hardness ranges between 65 and 80 Shore A.

These grades have been designed for coextrusiononto the copper leads used in the cable industry.Their mechanical properties are such that theinsulators are removable as specified by individualcable makers.

HTV silicone rubbers are used in cables because oftheir excellent electrical properties. The latter beingdesigned into these formulations for the most part.Within the cable grades there are again generalpurpose and speciality grades, this is summarised inTable 45 and referred to in Section 3.3. Table 45lists compliance with VDE Standard, VDE0303.

7.4.5 Oil Resistant HTV (NPC)

These products are similar in their oil resistance tooil resistant liquid rubbers. Likewise they are nopost cure grades as they contain an additive thatprovides the oil resistance. Such applications, beingtechnical in most cases, they will not require a postcure. Typically the hardness ranges from 40 to 80Shore A. The technique of reaching the oilresistance is the same as in the case of the respectiveLRs: special passive fillers and additives enable thisoil resistance.

Table 46 compares the oil resistance of an oilresistant HTV and a standard HTV. A higher fillercontent and a higher crosslink density aid oilresistance.

Silicone Elastomers

51

7.4.6 Electrically Conductive HTV

These rubbers are antistatic.

For moulding it is possible to use peroxide cured conductiveHTV. Its hardness ranges from 50 to 70 Shore A.

For extrusion, generally, an addition cured conductiveHTV is used. This is because the carbon black requiredfor the conductivity will deactivate peroxides in extrusion.

Typical applications would be body electrodes, leads forignition cables, conductive pills in keypads for consumerelectronics, stress cones for transmission anddistribution, etc.

The same conductivities are achievable as with conductiveLR. Again it is impossible to reach an intermediateconductivity of 1,000-5,000 Ωcm precisely enough toprovide antistatic but also insulating properties.

7.4.7 Super Heat Stable HTV

It is very unusual to have freely pigmentable andheat stable HTV. Not in the case of the highlycrosslinked super heat stable HTV. This material isheat stable without the need for a further stabiliser.Hence, it can be used at up to 300 °C.

With such advantages we also have to accept alimited selection of Shore A hardness and the factthat there are materials with better performance inextrusion.

A standard HTV would require a very good heatstabiliser to merely reach this level of stability. Thiswould imply the disadvantage of a loss inpigmentability. The colour restrictions will be to off-white to pastel colours. Table 47 shows heat ageingresults on freely pigmentable, super heat stable HTV.This material lasts up to 7 days at 300 °C.

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Silicone Elastomers

52

7.4.8 High Green Strength/Coolant Resistant HTV

High green strength products are usually good inextrusion. Some of them also are formulated such thatthey provide good coolant resistance. Recently theseproducts have started being used for turbochargerhoses, as well as radiator hoses. They are the preferredmaterial in the manufacture of fabric reinforced hoses.Their green strength is discussed under the section oncalendering (8.3.6).

7.4.9 Steam Resistant HTV

Such compounds will withstand dry steam at moreelevated temperatures than standard silicone elastomers.

Below 130 °C the steam resistance seems to be equalamong most HTV grades. Because of the drastically

increasing aggressivity of steam above this temperaturethe life time of silicone rubbers decays steeply.

While standard HTV grades show a life time at 160 °Cof 4-5 days (embrittlement and disintegration are thesymptoms of destruction), a steam resistant materialwill last for more than 6 weeks (Table 48).

7.4.10 Heat Conductive HTV

New heat conductive grades of HTV have beendeveloped. Their use is in rollers and otherapplications requiring electrical insulation, basicproperties of silicone rubber and heat conductivity ofup to 1.2 W/mK in extreme cases.

A comparison between the conductivities of standardand heat conductive HTV grades is shown in Table 49.

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Silicone Elastomers

53

7.4.11 HTV for Transmission and Distribution(T&D) Applications

These HTV grades exhibit outstanding electricalproperties.

They contain certain anti-tracking additives, fillers(e.g., aluminium trihydrate), etc.

As transmission and distribution applications such asinsulators work under the severest conditions theyrequire a very resistant material. Apart from all thegeneral advantageous properties of silicone rubber oneof the most demanding property requirements istracking resistance. T&D HTVs exhibit trackingresistance of 3.5 kV to 4.5 kV without a problem. As areference, standard HTV allows for 2.5 kV only.

Further, these materials have excellent resistance to anelectric arc and they are highly flame retardant. Also,as silicone rubbers are UV stable, they are the perfectmaterial for outdoor applications, which is documentedby experience over the last 30 years.

7.5 Addition Cured HTV

7.5.1 Introduction

One of the most prevalent disadvantages between HTVand LR has been the speed of curing because of thefaster crosslinking reactions for the LR compared toHTV. By changing from peroxide to addition curedHTV this difference has been compensated for or atleast diminished.

A further motivation for the increased use of additioncured HTV rubbers were the pharmaceutical

requirements, which have become stricter with respectto peroxide split products. Recently, the peroxides havebeen under discussion in Europe, as per likely changesto regulations, in particular for extrusion.

Another asset of the addition curing technique is the factthat it allows for nearly smell free production withoutany residual split products of peroxides. Consequentlythe as cured articles are considerably cleaner.

In addition, their appearance is more sterile, as they donot yellow, and their surface is much drier. The latteralso accounts for less stickiness between the siliconeparts themselves and also for better demouldingproperties.

Addition curing HTVs have more advanced mechanicalproperties as shown in a direct comparison to peroxidecuring HTVs in Table 50.

This table also indicates a remarkably lower modulusat equal Shore A hardness (this can be guessed fromthe elongation at break versus tensile strength).Behaviour like this is typical for addition cured HTVin moulding and extrusion.

7.5.2 Addition Curing

A distinction is made between one component and twocomponent systems. One component systems can beconsidered as mixtures of the two component systems(however the ingredients of the mixes have differentadditives and proportions).

One component (1K) systems have a shelf life of 3 to6 months, whereas the mixes of two components (2K)last for 1 to 7 days.

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Silicone Elastomers

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Table 51 gives examples of addition cured HTV gradesfor extrusion and mouldings, the mixing proportionsof the curing systems and some remarks.

7.5.3 Moulding: 1K Addition Cured HTV

This group of materials represents one of the latestdevelopments in silicone rubber technology. It goeswithout saying that it is quite contradictory if one wantsto have a fast curing material while having to stabilise itsuch that it does not cure at room temperature too quickly.

This has been achieved by using novel technology forsilicone rubber formulations. 1K HTV has alsodeveloped from the idea that processors want a ready-to-use compound, which they can put into the stufferbox of the injection moulding machine or the press.

Time and consequently cost pressure led them todemand a faster cure without increasing the complexityin the processing by having to mix a multi-componentsystem (the latter with a shorter pot life).

Essentially two product series have developed. Thefirst complies with most standard applications knownfor peroxide cured and organic rubbers. The second,a high tear strength series, has been designed to copewith advanced requirements in respect of tear andtensile strength.

Remarkably interesting is the fact that 1K HTV allowsfor the same speed of curing as the equivalent 2K HTV,as shown in Table 52. This table also shows thedifference in curing time of peroxide cured HTV andaddition cured LR.

As also mentioned under the upcoming processingsection, HTV rubber is available in pelletised form(however, there are a few restrictions). For the firsttime in the history of silicone rubber, this preform ofHTV allows for a fully continuous feed not only intoextruders but also to injection moulding machines. Thelatter has been a breakthrough in HTV technology, and,with addition curing and mould technology, HTVprocessing can be simplified as follows:

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55

• Fully automatic,• Waste free,• Short cycles.

This results in low cost per piece. Thus this HTV ismuch more competitive to organic rubbers and evenLR. Such production methods have been demonstratedby LWB and Maplan.

For example, an injection moulded tubing connectorwith a length of 10 cm, inner diameter of 4 cm andwall thickness of 7 mm requires a curing time of only50 seconds, while needing 180 seconds at 180 °C withperoxide cured rubber (and, of course much longer withorganic rubbers). A 200 t ENGEL machine with aspecial feeding system for pellets was used in this test.

7.5.4 Moulding: 1K Self Adhesive AdditionCured HTV

It has been possible to develop a self adhesive HTV whichis addition curing and also a one component material. Itsticks to many more substrates than self adhesive LRs do(while not sticking to the mould, see Figure 13).

The main intention is to provide a self adhesive materialwhich allows for rubber to metal adhesion, easily.

As with self adhesive LR this material does not requirea primer on the substrate. All the processor has to do

is degrease and dry it before applying this novelsilicone rubber.

7.5.5 Moulding: 2K Addition Cured HTV

Some processors prefer 1 component systems allowingfor a storage time of at least 3 months at roomtemperature.

Others, however, prefer to buy two separatecomponents which they can put on the shelf over ayear and mix them, when needed. At this point, theyhave to pay attention to pot life.

Anyhow, both concepts have their pros and cons, and Iwill try to elaborate them in this subsection in Table 53.

In general, 2 component materials will provide moredegrees of freedom with respect to the internal logisticsof a processor: components have a very long shelf life,and there is an increased flexibility as to colour additionand hardness adjustments.

As with peroxide cured materials a mix of two gradeswith different hardness will result in an intermediatevalue. The relation between the mixing ratio and theresulting hardness is almost linear, as shown inTable 54. The hardness of peroxide curing siliconerubbers can be adjusted in the same way.

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By using a 2 component system with a mixing ratio of100:1.5 or 100:2 the processors gain further flexibility.Firstly because of more convenient stock management.Secondly, in order to achieve an intermediate hardnessit is necessary to mix two large components (insteadof 4 as in the case of 1:1 systems). This becomes ofmore importance when the processor has to mix twodifferent viscosities. Thirdly, it is easier to control thetemperature of the mix.

In comparison to peroxide cured HTV, mouldableplatinum cured HTV silicones cure twice as quickly(in most applications). Hence, the process requires lessenergy per piece.

7.5.6 Extrusion HTV

As with peroxide cured HTV, the curing speed has tobe much faster for extrusion than for moulding in orderto allow for sufficient cure.

This is necessary, as the uncured extruded profile hasto remain in shape while passing through the curingtunnel. This shape stability is the green strength. Asthe temperature of the material rises while passingthrough the curing tunnel its viscosity drops. The greenstrength of the material could be destroyed by this drop.A quick speed of curing acts against the drop inviscosity, and it thus assists the stability of the shapeof the extruded goods.

7.5.7 Post Curing of Addition Cured HTV

It is essential for processors to pay attention to the factthat addition cured products must not be post cured (insome cases not even stored closely) together withperoxide cured extrusions or mouldings. This can leadto discoloration, smell and in extreme cases to severedamage to the HTV articles (the latter if stored inhermetic packaging).

8 Processing Silicone Elastomers

Because of the wide variety of industries and the vastnumber of different silicone elastomers, it is notpossible to describe all the processing techniques. I willconcentrate on the most well established processingtechnologies for groups of materials in order to give acomprehensive picture.

Especially in recent years, processors have developedmore and more ideas about how to process silicone

elastomers, which allows us to predict that there will bemany new processing technologies within the near future.

All silicone elastomers should be stored at moderatetemperatures, i.e., between 15 and 30 °C. It is notadvisable to keep the stock of silicone elastomers outsideof shop floors. During hot periods this leads to shortenedshelf life. Too cold a storage leads to condensation ofwater and thus undesired impact on reactivity.

8.1 RTV-1 Systems

RTV-1 materials are supplied in tubes, cartridges, pails,drums and bags. Basically they are pumped from thepackaging and applied as indicated on process guidesand data sheets.

It is imperative to pay attention to the fact that the curingspeed will revert into depolymerisation at 80 °C orhigher, and, that the user must allow for sufficient contactwith ambient air and in particular moisture. This moistureis an essential reactant during the curing step andtherefore indispensable.

Most materials are pumpable manually or automatically.They are applied by robots and/or spreading systems.

Organic solutions of RTV-1 in apolar solvents are easilysprayable.

In order to achieve maximum adhesion when using RTV-1 as adhesives, there must be intimate contact betweenthe glue and substrate(s).

The technical documentation contains hints onprocessing time, pot life and/or skin forming time. Theindustrial application process has to be chosen such thatprocessing occurs well before expiry of these processwindows.

It is highly advisable to take into account the fact thatmost of the stated properties of the cured rubbers developa couple of days after the cure to a tack free state. Thishas to be checked and implemented in the design of theapplication process prior to mass production.

8.2 RTV-2 Systems

For RTV-2 systems basically the same process guidelinesapply as for RTV-1. However, being 2 componentsystems much shorter processing times are possible.

In both RTV-1 and RTV-2 processing it is vital tomaintain a constant temperature relevant to the process

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step. The same holds for the humidity in the case ofcondensation curing materials.

The mixing ratios allow for certain tolerances in termsof process characteristics. However, an excess or lackof the components leads to varied speed of curing,embrittlement, stickiness, no cure and the like. Thus itis advisable to provide the correct mixing ratios byaccurate operating instructions and personnel training.

It is also vital to take into account differences in viscositiesof the single components. Low viscosity materials tendto stick to the wall of the mixing vessel which can lead todosage errors. Also thin liquids are best mixed into highviscosity media and not the other way round.

Uncured paste-like silicone RTV-2 components cancontain up to 20% dissolved air, especially if thecomponents are pumped by pressurised air. In suchcases the processor has to take care to deaerate thembefore use, particularly, if the curable mix is heated inorder to speed up the curing process. Incompletelydeaerated systems tend to form bubbles.

The processing of RTV-2 materials could be describedad infinitum, because RTV-2 processing includes manydegrees of freedom and many products. It is impossibleto explain everything in one go. The reader is stronglyencouraged to refer to literature on the raw materialsand also to documentation as supplied by equipmentmanufacturers.

Mould making will be described as an example of thecomplexity of processing.

8.2.1 Mould Making: Flexible Moulds

Mould making (flexible moulds) consists of thefollowing steps (a.10):

• Make and prepare a model,

• Get raw materials ready (single components),

• Meter and mix the components,

• Deaerate the mix (air is entrapped after storage andduring mixing),

• Make the mould.

In order to prevent sticking problems the model surfacehas to be free of porous, moisture absorbing (condensationcuring systems!) and silicone/silicate containing surfaces(in particular ceramics, glass, etc.). This can be done bycoating the model with polyvinyl alcohol, methylcellulose, soft soap or Vaseline.

In the case of addition curing RTV-2 systems one has totake care that the model does not inhibit the cure.Otherwise one has to apply a coating to the model.

It is highly advisable to thoroughly stir pourable RTV-2silicone rubber components prior to their use torehomogenise them. The same has to be done withcomponents that have high viscosity with high mechanicalproperties.

The components should be dosed accurately. Variousequipment can be used in metering. Again the equipmentmust be free of inhibitors if addition curing materials areto be processed.

The mix must be homogeneous in order to ensure uniformcuring characteristics.

Pourable and spreadable products can be mixed by handwith a spatula or, for larger amounts, with a mechanicalstirrer or automatic mixing and metering equipment (thelatter can be fully automated). Kneadable compounds aremixed on a triple roll mill or in a kneader.

To obtain vulcanisates without any air bubbles, pourablegrades have to be deaerated in a desiccator or vacuumcabinet at reduced pressure.

Spreadable, non sag and kneadable mixes cannot easilybe deaerated. In this case, first a thin, bubble-free primerof a pourable grade is applied to the surface of the modelfollowed by the spreadable or kneadable compound.

Flowable RTV-2 silicone rubbers are poured over themodel, spreadable and non sag compounds are appliedusing a spatula. Kneadable grades in the form of a sheetare pressed on the model surface by hand or using a roller.

With flexible silicone moulds, undercuts can bedemoulded by stretching the mould.

Apart from the versatile properties of silicone elastomers,RTV-2 silicone has advantages over organic elastomersin mould making:

• Easy processing,

• Extremely flexible when cured and durable,

• High strength grades are available, which are tearresistant,

• Excellent release properties, and

• Relatively safe raw materials compared with, e.g.,polyurethanes.

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8.2.2 Mould Making: Block Moulds

One part block moulds are normally used to copysingle sided objects such as stucco, coins, etc. Themodel is put into a box and covered using flowablesilicone, or, it is impressed into a block or strip ofkneadable silicone rubber.

This is related to spin casting.

It is possible to cut the ready made mould along aparting line in order to allow for better demoulding.These multipart moulds are advantageously made fromtransparent silicone rubbers. Two-part block mouldscan be made by pouring a one-part block mould andcutting it open along a parting line.

8.2.3 Mould Making: Skin Moulds

For large models or ones with deep undercuts, a skinmould is the choice with 5-10 mm thickness.

Skin moulds require less material but they are labourintensive. Thus the mould maker has to assess theeconomics of each moulding job.

Skin moulds result from pouring or spreadingtechniques. Smaller horizontal models are best copiedusing the pouring method.

The model is covered with clay or plastilline. Thethickness of the spacer determines the thickness ofthe skin mould. The rigid layer is put on top of thespacer. It is poured (plaster or casting resin) or spreadin a few layers (polyester, polyurethane or epoxyresin, etc.). After curing it is separated from thespacer. The latter is no longer needed. The supportcontaining air vents and feeding holes is now putover the model. The silicone rubber is fed throughthe feeding hole and left until it is entirely cured.After demoulding the model and recombiningsupport and mould, the skin mould is ready to receivethe reproduction material.

Too large or vertical models are reproduced by thespreading technique. This is a layering method, asdescribed before. A thin primer of pourable siliconerubber is applied to the model. This primer guaranteesthe copying of fine details of the model. After a partialcure a top layer of non sag silicone rubber is appliedusing a spatula. The support consists of fabric stripssoaked in plaster or a fibreglass-reinforced organicresin. The demoulding stages are identical to those ofthe pouring technique.

8.3 LR and HTV

8.3.1 Press Curing HTV

In press curing the processor preforms HTV into piecesof the required size and puts them into a hot mould.The two halves of the mould are mounted in a hydraulicpress. The press closes and the curing takes place. Afterthe cure the processor demoulds the parts manually.

As a post treatment he has to remove flash, which is aresult of internal mould pressure and to check the partsfor incomplete cure, which is particularly important inperoxide cure technology.

In press or compression moulding the processor has toput silicone rubber pieces into each cavity.

8.3.2 Transfer Moulding HTV

In transfer moulding the mould is equipped with areservoir into which the processor puts the rubber.Ideally the temperature of the reservoir is well regulatedwhile not affecting the thermal balance of the mouldwhich is located below it.

The transfer process has the advantage of being ableto provide silicone rubber to multiple single cavitiesand also to fill moulds that have long flow paths.

In transfer moulding one would typically use the samepress as for compression moulding.

Both, transfer and press moulding are processingtechniques most suitable for small series production(or mass production with a wide variety of geometries).However, press curing and transfer moulding will notcompete with injection moulding, if it gets to largerscale production.

Mould design in these two technologies is less criticalthan in injection moulding. But it is well known thateven in these basic technologies of silicone HTVprocessing it is a must to obey the ‘rules of silicone’by applying the correct conditions. In many discussionswith processors these conditions have improved themoulding result upon changing these parameters:

• Moulding temperature (not below 160 °C, ideallyat 180 °C),

• Clamping force (as high as possible, variable),

Silicone Elastomers

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• Mould surface (electroeroded, sand or glass pearlblasted; a smooth or polished surface increasesstickiness),

• Mould release agents ONLY if necessary,

• Internal mould release agents to be avoided wherepossible,

• Volume of the parts to be balanced with the forceof the press.

8.3.3 Injection Moulding LR and HTV

Injection moulding technology easily outdoes the twolatter moulding techniques. It allows for fully automaticprocessing with essentially no need for personnel. Thus,the human factor is negligible in the outcome of theprocessing, or at least it is constant, if the settings ofthe injection moulding machine are kept constant.

As in most fully automatic processes the technicalrequirements for the moulds are stricter than in theprevious cases.

8.3.3.1 Injection Moulding HTV

In the case of HTV an injection moulding machine isfed via a piston (up to 25 l) which presses the siliconerubber into the barrel of the machine. The screw of themachine takes in the required injection volume whilemoving backwards. When finished the screw is pushedforward and this volume is injected into the mould.

In order to avoid back flow of the material the tip ofthe screw is equipped with a check valve. The nozzleof the barrel has a needle shut off valve.

As the rubber cures at elevated temperatures it shouldbe kept as cold as possible during the injection. This iswhy a good injection moulding machine allows forgood temperature control of the rubber during themetering and injection steps.

If the temperature control becomes inefficient, e.g.,because of frictional heat, the injected rubber couldstart to cure prematurely, resulting in filling defects.Hence, it is essential to keep the rubber cold as long aspossible during injection while it should cure as quicklyas possible after filling the mould.

This is achieved by using a cold runner system. This isa manifold which distributes the curable HTV rubber

directly to the single cavities. The cold runner istemperature controlled up to the tips of the nozzles ofthe manifold system. It goes without saying that it isdifficult to design such mould concepts as it is notobvious how to apply cold nozzles hermetically to hotcavities. This is the trick and the know how of the mouldmakers. The hot mould is at 170 to 220 °C. Theinjection volume is kept at room temperature and insome cases up to 60 °C (the latter only in the case ofperoxide cured HTV) in order to reduce viscosity. Thecold runner will typically heat up to approximately40 °C. The nozzles of the cold runner are either openor needle operated.

The injected volume trapped in the cavities heats upwhile having time to cure. As the silicone heats up italso expands. This is why it exerts an internal pressureto the surface of the mould of up to 500 bar. Thispressure has to be compensated for by the clampingforce of the injection moulding machine. Oversizedmoulds (too many cavities and/or too high a cavityvolume) result in defective parts.

The feeding of HTV into the piston (stuffer box) ofcourse is in contradiction to a fully automatic process,particularly if we also consider the fact that the rubberbase has to be mixed with the curing additives on rollermills before being charged. Using advanced mouldingtechnology it is possible to process HTV rubberscompletely waste free and fully automatic between twocharging cycles. Now, these charging cycles may nolonger be relevant.

Injection of HTV is at a revolutionary stage ofdevelopment at the moment. HTV is now available inpellet form. Figure 14 shows the concept of the feedingsystem which prevents bridge formation (thus blockingby electrostatic charge of the HTV pellets). It is possibleto feed the pellets over distances of 20 m out of boxesor vessels of almost infinite size. As a consequence,no storage space is necessary close to the machine.

The processing is further facilitated by the fact that itis possible to add pelletised colour masterbatches.

8.3.3.2 Injection Moulding LR

Liquid silicone rubber has a much lower viscosity thanHTV. This is why the strict requirements as to mouldtechnology are even stricter for LR. The tolerancesalong parting lines have to be as low as possible. Atthe same time, as the speed of injection is much fasterthan with HTV and the viscosity much lower, thecavities have to allow for removal of air.

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Furthermore, LR moulds have to work fully automaticupfront, in order to allow for the desired productivity.Because of the speed of curing one also wants toincrease the number of cavities in order to allow for amaximum number of parts per cycle (today it is possibleto produce up to 256 parts per shot).

All these needs and properties require an utmost degreeof experience in machinery and mould design. Thereare approximately 10 mould makers worldwide whoknow how to construct competitive moulds for LR.

As to machinery, the number of machinery suppliersbeing as small or smaller, the requirements are stricteras well. Because of the increased speed of curing onehas to pay attention to the thermal regulation. The lowviscosity requires specially constructed check valvesat the tip of the screw.

Because of their curing mechanism liquid siliconerubbers are two component systems. LRs are suppliedas two components with a mixing ration of 1:1. Specialpumping units pump the material from drums into astatic mixer, which leads the curable mix into the barrelof the injection moulding machine.

As in HTV the cold runner will consist of a wellbalanced manifold system with open or needle shut offnozzles. The maximum numbers of cavities are 256 or64, respectively.

The processing system essentially consists of apumping unit ensuring a 1:1 mixing ratio of A- and B-components (where component A contains the Ptcatalyst and B the Si-H crosslinker), the injectionmoulding machine (using a static mixer the 1:1 A andB flows result in an intimately mixed curablecomposition) and a cold runner mould for liquid rubber.

In quiescent state the AB mix and also the singlecomponents have a paste like consistency. Theirviscosity typically ranges from 100 to 8,000 Pas. Oncesheared the viscosity drops dramatically. Hence, whenpumped the viscosity drops by a factor of 2-4, wheninjected through the cold runner nozzles the materialturns into a liquid with a consistency of syrup.

This consistency allows for the use of injectionmoulding machines with a relatively low clampingforce. Preferably this is between 80-100 tons. However,special applications such as high volume articles witha high projected surface require up to 400 tons.

The low viscosity also favours long flow paths andcomplex geometry, the latter with very precise tolerances.

Figure 15 describes the processing system. The mouldsymbol comprises the cold runner and the hot mould.The material is kept relatively cool until the end of thecold runner, when it enters a hot mould.

Figure 14

Feeding system for HTV pellets as used in moulding and extrusion

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The cold runner acts a manifold that allows for thetransport of the liquid material directly to the cavities.Its task is to keep the material cold until it enters thehot cavity through the nozzle which is also cooled. Inthe market for liquid silicone rubber moulds such coldrunners can manage up to 128 cavities. The nozzlesare either open, or equipped with needle-shut-offvalves. Both concepts are widely used and each has itspros and cons.

It is highly advisable that interested processors contactmould makers specialising in LR processing. Basedon drawings and article specifications they provide thebest information as to:

Thermal separation between cold runner and hotmould,

Heating of the mould (this is usually insufficientin less experienced mould makers),

Balancing the cold runner manifold in order toprovide uniform flow and thus mould filling,

Numbers of cavities,

Mould design, LR allows for flash free productionwith no waste at all,

Allowing for thermal shrinkage of LR (as shownin Figure 16, please note this is also considerable

when designing HTV moulds!), tolerances, andventing during the filling stage,

Selection of steel quality. It is essential to use thecorrect steel which allows for proper demouldingand life time of the mould,

Spare parts and after sales service,

Training,

Selection of the machine size or adaptation to agiven machine specification,

Demoulding and other automation aids such asrobots, etc.,

They sometimes also offer packages includingeverything.

It goes without saying that processing liquid rubber isnot possible with a machine that is used for thermoplasticinjection and/or high consistency rubber. The machinerysupplier must be prepared to provide a so-called LIM(liquid injection moulding), package. A typical technicalterm in this respect is therefore ‘LIM machine’.

As mentioned before, there are a few machine suppliersthat would be able to provide the knowledge as statedabove for mould makers. It goes without saying thatexperienced machinery and mould makers maintainrelationships which prove productive in each project.

Figure 15

Processing of liquid silicone rubbers

Mode of operation of an injection moulding machine.

ELASTOSIL® LR is suitable for virtually all meteringand mixing equipment,

1 Metering device for Components A and B of theliquid silicone rubber

2 Metering device for pigment (if required)

3 Mixing device

4 Mould

5 Heated injection mould with injection moulding part

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62

8.3.4 Extrusion of HTV

The major processing techniques of solid siliconerubber are 60% extrusion and 40% moulding. Alesser amount is used in calendering and textilecoatings.

In extrusion, catalysed solid silicone rubber is fedinto an extruder designated for silicone processing.Ideally the screw has a core and/or flight progression.As the screw fulfils various tasks such as feeding,deaeration, residual mixing and replastification (thelatter is of importance, e.g., in the use of siliconerubber pellets) it must have an L/D ratio of 12 to 18.

a) Extruder

The extruder should be well thermally regulated toambient temperature. Its design should allow for easychanges of nozzles and filter screens and its head(and nozzle) should be coolable.

For cable extrusions and multilayer extrusions (suchas in fabric reinforced hoses) the extruders areequipped with so-called cross heads. Ideally anysilicone extruder should include an option for thisset up.

The drive of the extruder should allow for a widerange of rpm. Torque, pressure and temperaturereadings have proven to be useful.

b) Curing tunnel

Most typically the curing furnace or tunnel ishorizontal. It is equipped with a conveyor belt for thetransport of the extruded profile.

If it is essential to produce profiles without any beltmarks, one has to use a shock oven (approximately50 cm long, up to 850 °C) that quickly cures the outerskin of the profile in front of the furnace.

Figure 17 shows a scheme of this set-up. It is importantthat the furnace is long enough, with a wide range oftemperatures, and good and homogeneous heat transferand distribution.

In the case of both the shock zone and the curingtunnel it is highly advisable that a minimum ofirradiation heat gets to the extrusion die. Thisminimises scorch and allows for ideal control ofmaterial viscosity. The latter – this is obvious butimportant – is a function of temperature.

8.3.5 Moulding HTV (General)

Most typically mouldable HTV silicone rubbers areprocessed by press curing, transfer or injectionmoulding.

The typical curing temp is between 170-200 °C.

Figure 16

Linear shrinkage of LR (ELASTOSIL® LR 3003/50) as a function of moulding temperature and flow directions(a) lengthwise, post-cured; (b) lengthwise, not post-cured; (c) broad-side, post-cured; (d) broad-side, not post-cured

Silicone Elastomers

63

In order to facilitate demoulding, the mould surfacesneed treatment. In many cases it is sufficient to use adetergent or an internal release agent as an additive tothe formulation of the silicone rubber.

In more sophisticated moulds special surface structureslead to desired moulding results. C1 and C6 typicallyare the peroxides used in moulding applications. Foraddition curing moulded parts one has to apply therespective addition curing moulding grade, and forextrusion, a special extrusion grade. In extrusion andmoreover in the following section dimensional stabilityand mechanical strength are important even before thecure of the product.

8.3.6 Calendering HTV

Some solid silicone HTV rubbers are designed forprocessing by calendering. During calendering siliconerubber passes through 3 or more rollers while beingformed into a strip. Often calendering is used forpreforming rubber strips on fabrics or just simple stripswhich then cure.

Often it is important to use a so-called high greenstrength rubber which allows for sufficient mechanicalstability of the uncured strips. Such high green strength

rubbers (e.g., ELASTOSIL® R 760/60-70) not onlyexhibit high stability of strips, they would also be goodmaterial for extrusion. Thus a high green strengthusually means good extrudability. One of the measuresfor high green strength are the viscosity parametersWilliams plasticity and Mooney viscosity. However,as in calendering the high green strength behaviour ismore a result of elongation flow (strips are pulled),there is no direct parameter that would fully describehigh green strength behaviour.

Table 55 gives a comparison of standard siliconerubbers versus high green strength silicone rubbers andtheir preferred use.

Fabrics need pre-treatment with primers before coatingwith silicone rubber strips in order to provide goodadhesion between rubber and fabric. Different primersare required for different elastomers and substrates.

The fabrics can be coated with solvent containingprimers. The application is such that the fabric is coatedwith the primer by immersion, painting, spraying, etc.After drying off the solvent it is advisable to cure theprimer at approximately 130 °C for say 10 minutes.

The primers must be protected from moisture. As aconsequence it is essential to apply them onto a dry ordried fabric.

Figure 17

Extrusion line for HTV

VTHsrebburenocilisdilossuoiravforuoivaheb)SGH(htgnertsneerghgihfonosirapmoC55elbaT

epytlairetaMLISOTSALE( ® )edarG,R

ytisocsivyenooM)eulavdne;tratS(

yticitsalpsmailliW noitacilppA

dradnats,07/104 06;66 313 esopruplareneG

SGH,06/204 65;95 872 noisurtxE

SGH,57/204 27;18 203 noisurtxE

SGH,07/067 86;17 004 noisurtxe,gnirednelaC

Silicone Elastomers

64

Another technique is to apply a so-called adhesive basewhich is previously calendered onto the fabric in therequired thickness. The adhesive base allows extremelyhigh adhesion. Cohesive failure is often found in tests.It is popular to use the adhesive base in the manufactureof rollers.

A more detailed description of primers is beyond theintended scope of this article (see a.11, a.12, andtechnical bulletins from material suppliers).

One of the most prominent examples of applicationsfor calendered goods is fabric reinforced hoses as oftenused in the automotive industry. Such hoses are usedas coolant or turbocharger hoses (the latter are verysophisticated composites). The calendered HTV/fabricstrips are wrapped in layers around preformedmandrels. The outer layer is then protected with abandage of, e.g., polyethylene terephthalate (PET).

For pressureless curing one can use crosslinker E.However, typically one uses C1 or C6 with bandagesprotecting the catalysed rubber from contact withoxygen. The curing takes place in steam autoclaves.

8.3.7 Rollers

The components of rollers are an elastic silicone rubberlayer which adheres to a solid metal or plastic core.Again, one can use a primer or a special adhesive baseto provide the adhesion between solid/elasticcomponents.

Rollers are cured with crosslinkers C1 or C6, as thecompression set is much lower than in the case ofcrosslinker E. The same bandages apply for rollers asin case of calendering.

After curing in a steam autoclave the bandages areremoved, and the roller surface gets its final finish bygrinding.

8.3.8 Bonding

Composites of hard and soft materials such as thepreviously mentioned rollers and calendered articlesoften require adhesion between substrate and silicone.Silicone rubber bonding has been reviewed (a.11).

The most spectacular developments in the recent pastrefer to self adhesive technology.

Self adhesive silicone rubbers are demouldable (withthe exception of adhesive bases) while sticking to thesubstrate.

For rubber to metal applications the latest developmentis an addition cured one component solid siliconerubber. It cures rapidly and adheres well to steel andvarious plastics.

9 SUMMARY

The versatility of silicone elastomers is enormous,which is why this review has only covered the majorapplications, groups of materials and the mostimportant processing techniques.

Textile coatings have been mentioned as an extra fieldof applications. This field and some others would againfill an article of this size.

The beauty of silicone elastomers is that they showmany advantages over organic rubbers, such as easyprocessing, much shorter processing times, andimproved physical and chemical properties. Just bytheir appearance and pigmentability, their inert andbiocompatible compositions, silicone elastomers havea great number of future applications. Because of thesefeatures silicone elastomers are being used to substituteorganic rubbers.

Silicone elastomers are special: there is no othermaterial exhibiting a similar spectrum of propertiesbecause of the silicone chemistry. The behaviour is notentirely inorganic and not entirely organic. Thestructure of a polydimethyl siloxane is apolar andchemically quite inert. Silanes and silicones undergochemical reactions by laws that are different to thoseof organic molecules. It took the industry more than50 years of the last century to characterise thischemistry and use it in elastomers.

The seemingly small material family of siliconeelastomers will continue to develop in variety ofmaterials, innovative individual types and specificadvantages in processing. For example, 10 years agonobody would have expected HTV rubber to be availablein pellet form, to allow fully automatic processing andwith no need for secondary treatment because the curingsystem has such a low level of emissions.

Who would have thought that there could be a selfadhesive silicone elastomer that would stick to substrates

Silicone Elastomers

65

when moulded while not sticking to the mould? The latterwould not even require a release agent!

One can predict many such surprises as siliconeelastomers develop further. Innovations will strengthenand complement current advantages and will contributeto many different problem solutions. For example,saving energy, protecting the environment, savinghuman lives, and, of course, much more.

ADDITIONAL REFERENCES

a.1 W. Noll, Chemistry and Technology ofSilicones, Verlag Chemie, Weinheim, 1968.

a.2 A .Tomanek, Silicone und Technik, Wacker-Chemie, Carl Hanser, Munich, 1990.

a.3 UL2196, Tests for Fire Resistive Cables,2001.

a.4 UL94, Tests for Flammability of PlasticsMaterials for Parts in Devices andApplications, 1996.

a.5 ISO 4589, Plastics – Determination ofBurning Behaviour by Oxygen Index, 1996.

a.6 ASTM D 2863, Standard Test Method forMeasuring the Minimum OxygenConcentration to Support Candle-LikeCombustion of Plastics (Oxygen Index),2000.

a.7 BS 6853, Code of Practice for FirePrecautions in the Design and Constructionof Passenger Carrying Trains, 1999.

a.8 K. Wieczorek, High Performance Elastomers2000, Berlin, Germany, 2000, Paper 10.

a.9 ASTM D624-00e1, Test Method D624-00e1Standard Test Method for Tear Strength ofConventional and Vulcanized Rubber andThermoplastic Elastomers, 2000.

a.10 G. Kollmann in Organosilicon Chemistry IV,Ed., N. Auner and J. Weis, Wiley-VCHWeinheim, 2000, 710.

a.11 P. Jerschow and W. Strassberger in Handbookof Rubber Bonding, Ed., B. Crowther, RapraTechnology Ltd., Shawbury, UK, 2001, 287.

a.12 P. Jerschow, Rubber Bonding 2000,Amsterdam, The Netherlands, 2000, Paper 14.

ABBREVIATIONS ANDACRONYMS

BgVV Bundesinstituts für gesundheitlichenVerbraucherschutz und Veterinärmedizin

C1 Dicumyl peroxide

C6 2,5-(bis-t-butylperoxy-)-2,5-dimethylhexane

CIPG Cured-in-place-gasket

CS Compression set

E 2,4-dichlorodibenzoylperoxide

ECU Electronic control unit

EPDM Ethylene-propylene terpolymer

EtO Ethylene oxide

FDA US Food and Drug Administration

FIPFG Formed-in-place-foamed-gasket

FIPG Formed-in-place-gasket

GMP Good manufacturing practice

GP General purpose

HCR High consistency rubber

HGS High green strength

HTV High temperature vulcanising, solidsilicone rubber

IC Integrated circuit

LIM Liquid injection moulding

LOI Limiting oxygen index

LR Liquid rubber

LSR Liquid silicone rubber

MEG Monoethylene glycol

NPC No post cure

NR Natural rubber

PA Polyamide

PBT Polybutylene terephthalate

PC Post cure

PC Polycarbonate

Silicone Elastomers

66

PDMS Polydimethyl siloxane

PET Polyethylene terephthalate

PF Phenol-formaldehyde resin

PMMA Polymethyl methacrylate

POM Polyacetal

PP Polypropylene

PPE Polyphenylene ether

PPO Polyphenylene oxide

PPS Polyphenylene sulfide

PU Polyurethane

PVC Polyvinyl chloride

RTV Room temperature vulcanising

RTV-1 Room temperature vulcanising, onecomponent

RTV-2 Room temperature vulcanising, twocomponent

T&D Transmission and distribution

t90 Time needed to reach 90% vulcanisationunder isothermal conditions

TPE Thermoplastic elastomer

UL Underwriters Laboratory

UV Ultraviolet

VDE Verband Deutscher Elektrotechniker

XLR® Extra liquid rubber

References and Abstracts

© Copyright 2001Rapra Technology Limited 67

References from the Rapra Abstracts Database

Item 1Patent Number: EP 1106654 A2 20010613

SILICONE RUBBER COMPOSITION KEYPADSSugimoto S; Sato T

Dow Corning Toray Silicone Co.Ltd.

The above composition comprises a silicone rubber base

produced by mixing under heat (A) a crosslinkable

diorganopolysiloxane and (B) 20 to about 250 parts by

weight calcium carbonate powder per 100 parts by weight

of component (A), and (C) a curing agent consisting of

(i) an organic peroxide or (ii) an organohydrogen-

polysiloxane and a platinum catalyst in an amount

sufficient to effect cure of the composition.

EUROPEAN COMMUNITY; EUROPEAN UNION; JAPAN;

WESTERN EUROPE-GENERAL

Accession no.818527

Item 2Revue Generale des Caoutchoucs et Plastiques

77, No.790, Nov.2000, p.68-9

French

ENGEL: THE PLASTICS TRUMP CARDDelannoy G

An account is given of developments by Engel in injection

presses, including vertical and horizontal machines for

rubber moulding, special machines for the processing of

silicone rubbers, and machines for use in multi-material

moulding.

ENGEL; ENGEL FRANCEAUSTRIA; EUROPEAN COMMUNITY; EUROPEAN UNION;

FRANCE; WESTERN EUROPE

Accession no.818407

Item 3Patent Number: US 6184260 B1 20010206

METHOD FOR MAKING NANOPOROUSSILICONE RESINS FROMALKYLHYDRIDOSILOXANE RESINSZhong B

Dow Corning Corp.

A method for preparing a nanoporous silicone resin which

can be used to form low dielectric constant films useful

for electrical insulating coatings on electronic devices

comprising (A) contacting a hydridosilicon containing

resin with a 1-alkene comprising about 8 to 28 carbon

atoms in the presence of a platinum group metal-

containing hydrosilation catalyst effecting formation of

an alkylhydridosiloxane resin where at least 5 percent of

silicon atoms are substituted with at least one group

comprising about 8 to 28 carbon atoms and at least 45

percent of silicon atoms are substituted with at least one

hydrogen atom and (B) heating the alkylhydridosiloxane

resin of step (A) at a temperature sufficient to effect curing

and thermolysis of alkyl groups comprising about 8 to 28

carbon atoms from the silicon atoms thereby forming a

nanoporous silicone resin.

USA

Accession no.817427

Item 4Journal of Sol-Gel Science and Technology

21, No.1/2, June 2001, p.75-81

BIOACTIVITY AND MECHANICALPROPERTIES OF POLYDIMETHYLSILOXANE(PDMS)-CAO-SIO2 HYBRIDS WITHDIFFERENT PDMS CONTENTSKamitakahara M; Kawashita M; Miyata N; Kokubo T;

Nakamura T

Kyoto,University

Hybrid materials were synthesised by a sol-gel process frompolydimethylsiloxane (PDMS), calcium oxide, and silicon

dioxide as potential bone replacement materials. They wereinvestigated for their surface apatite formation and releaseof silicon in simulated body fluid, and subjected to Fouriertransform infrared spectroscopy, thin film X-ray diffraction,and three-point bending mechanical tests. The surfaceformation of apatite is a measure of the materials ability to

bond to bone in situ. The surfaces were examined byscanning electron microscopy. The material with PDMS :tetraethoxysilane (TEOS) + PDMS weight ratio 0.3,calcium nitrate : TEOS molar ration 0.15 and water : TEOSmolar ratio 2 showed high apatite-forming ability, lowsilicon release, and mechanical properties similar to human

cancellous bone. 26 refs.

JAPAN

Accession no.817314


COMPOSITION FOR FILM FORMATION,METHOD OF FILM FORMATION, ANDINSULATING FILMKurosawa T; Hayashi E; Youngsoon S; Konno K;

Shiota A; Yamada K

JSR Corp.

A polyorganosiloxane-based composition for film

formation, which gives a film having low dielectricconstant and high elastic modulus and which is useful asan interlayer insulating film in semiconductor devices,comprises (A) a product of hydrolysis and condensationobtained by hydrolysing and condensing, in the presenceof an alkali catalyst, at least one compound(s) of given

formulae and (B) a product of hydrolysis and condensationobtained by hydrolysing and condensing, in the presenceof an acid catalyst, at least one of the above compounds.



Accession no.817003


68 © Copyright 2001 Rapra Technology Limited

Item 6Rubber and Plastics News

30, No.21, 14th May 2001, p.12

DOW SILICONE SEALANT OFFERS UV,WEATHER RESISTANCE

Dow Corning’s 700 Industrial Grade Silicone Sealant has

been used by an unnamed car manufacturer to re-coat a

PVC-jacketed electrical cable that had faded and cracked

from weathering and exposure. Rather than replace the

cable, Dow Corning suggested the sealant as an alternative

remedy. After testing the adhesion and UV protection of

the silicone formulation, an industrial painting engineer

was employed to coat 7,200 feet of cable on the

automaker’s plant roof, saving the company about

400,000 US dollars. The sealant cures at ambient

temperatures to a tough, rubbery solid that is virtually

unaffected by UV light, ozone, rain and extreme

temperatures.

DOW CORNING CORP.USA

Accession no.816787


30, No.21, 14th May 2001, p.11-2

FULL OF PROMISEMcNulty M

Silicone rubber has been popular in the automotive and

medical device industries for some time, but it is emerging

as a more commonly used material in the electronics,

aerospace, sealants, baby products and a wide assortment

of other markets. Annual growth is estimated at around

4-5%. NuSil Technology attributes the steady

improvement to several factors, including silicone’s

ability to perform well under extremes. Liquid silicone is

ideal for the healthcare industry because it is clean and

has the ability to withstand chemical and foreign body

contamination. The material has also benefited from fears

of allergies related to natural rubber latex. In the

electronics industry, silicone is used for coating systems,

electrically and thermally conducted applications and as

an insulating application.

USA

Accession no.816786


ELECTRON BEAM TREATMENT OFSILOXANE RESINSTreadwell C; Yang J; Ross M

Disclosed are electron beam cured siloxane dielectric

films, which are useful in the production of integrated

circuits. A siloxane polymer having less than 40 mole

percent carbon containing substituents or at least

approximately 40 mole percent carbon containing

substituents may be cured by wide beam electron beam

exposure.

USA

Accession no.816249

Item 9Kunststoffe Plast Europe

91, No.4, April 2001, p.32-3

SILICONE BONDSKraibuhler H

Arburg GmbH

New injection moulding concepts are discussed which

have been instrumental in the increase in the use of

injection moulded silicone parts for technical applications.

Such developments include multi-component

applications, sprueless injection moulding, and economic

micromoulding thanks to new micro-metering units.

(Article translated from Kunststoffe 91 (2001) 4, pp.88-

89).

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.815269


THERMAL CONDUCTIVE SILICONE RUBBERCOMPOSITIONS AND METHOD OF MAKINGNakano A; Hashimoto T

Shin-Etsu Chemical Co.Ltd.

Silicone rubber parts having a high thermal conductivity

and low hardness are obtained by moulding and curing a

composition comprising (A) 100 parts by weight of an

alkenyl-bearing organopolysiloxane having a viscosity of

up to about 500,000 centistokes at 25 degree C., (B) 300-

1, 200 parts by weight of aluminium oxide powder, (C)

0.05-10 parts by weight of an alkoxysilane of the formula:

R1a Si(OR2)(4-a) wherein R1 is a monovalent 6-20 C

hydrocarbon group, R2 is a C.sub.1-6 alkyl group, and

a=1, 2 or 3, (D) a platinum group metal catalyst, and (E)

an organohydrogenpolysiloxane containing at least two

SiH groups in a molecule. The composition is formulated

so as to suppress the viscosity increase of a liquid silicone

rubber composition due to heavy loading of aluminium

oxide.

JAPAN; USA

Accession no.815127

Item 11Rubber and Plastics News 2

22, No.13, 9th April 2001, p.3

WACKER-CHEMIE ADDS TO LIQUIDSILICONESBegin S

Wacker-Chemie has expanded its line of cost-saving, self-

adhesive liquid silicone rubbers. Last year the company



finalised development of nine additional grades of

Elastosil LR for the automotive industry. The grades differ

according to their resistance to temperature, oil and

coolant. Elastosil LR is said to be ideal for overmoulding

thermoplastics and metal parts, in applications ranging

from exhaust pipe hangers and engine mounts to

multifunctional steering wheel switches, air regulator

membranes and automotive cables. Elastosil LR grades

incorporate an adhesion agent which slowly diffuses out

of the rubber and then sticks between it and the plastic or

metal during two-component injection moulding. Metal

and plastic substrates can remain unprimed, saving cost

and time.

WACKER-CHEMIE GMBHEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.814724

Item 12Patent Number: US 6159398 A1 20001212

METHOD OF MAKING REPLICAS WHILEPRESERVING MASTERSavant G D; Hosseini A

Physical Optics Corp.

An improved method of making laminated optical

components using a master and several submasters is

disclosed. A glass/photoresist master is made by recording

optical surface features in the photoresist with coherent

or incoherent light. The master is processed to reveal the

surface features. A frame is fastened to the edges of the

photoresist/glass master with edges rising slightly above

the top surface of the master. Silicone rubber is poured

into the frame over the photoresist layer and allowed to

cure. The silicone rubber submaster is then separated from

the photoresist/glass master. Use of silicone rubber

permits separation of the submaster without damaging

the master. Additionally, silicone rubber is less prone to

shrinkage than prior art submasters, thus permitting more

accurate copying of the surface features of the photoresist/

glass master. Subsequent epoxy replicas may then be made

from the silicone rubber submaster.

USA

Accession no.813549


30, No.16, 5th March 2001, p.16-7

PLUG-LESS SILICONE GASKETS OFFER NEWWAY TO FIRE ENGINEBegin S

The advantages of a new gasket, called the Multiple Spark

Ignition Gasket, developed by Gasket King, are

highlighted. The gasket consists of a pre-ceramic silicone

rubber with fabric reinforcements and a wire ignition

system embedded in the middle of the gasket. Location

of a multiple spark in the gasket creates “surround

combustion”, an optimal method of burning fuel in an

engine’s combustion chamber. The gasket may be

retrofitted on current engines without major changes to

the engine and is expected to greatly minimise emissions

and increase fuel efficiency.

GASKET KINGUSA

Accession no.813046

Item 14Materie Plastiche ed Elastomeri

65, Nos.7/8, July/Aug.2000, p.560/9

Italian

PLASTICS THAT DENTISTS LIKEBaucia G

Applications of plastics, filled composites and silicone

rubbers in dentistry are examined with reference to

materials and product developments by a number of

companies. Dentists’ chairs and associated equipment

produced by Italian companies and incorporating plastics,

composite and PU foam components are also described.

EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY;

WESTERN EUROPE; WORLD

Accession no.812725

Item 15International Polymer Science and Technology

28, No.2, 2001, p.T/6-8

OIL BLEEDING BEHAVIOUR OF SELF-LUBRICATING LIQUID SILICONE RUBBERSPohmer K

Wacker-Chemie GmbH

The diffusion of silicone oil from self-lubricating liquid

silicone rubbers is examined. Methylphenyl silicone oils,

added to self-lubricating liquid silicone rubbers distribute

homogeneously in rubber and are incompatible with

silicone rubber. This incompatibility is the result of the

differences in the chemical potential between the two

phases of the system. Factors affecting the diffusion or

bleeding of oil from the rubber are examined, with

reference to applications such as automotive weather

seals. 5 refs. (Translated from Gummi Fasern Kunststoffe,

No.10, 2000, p.709)


WESTERN EUROPE

Accession no.811250


IOLS AND PRODUCTION METHODS FORSAMETran D Q; Lind R J

Allergan

Intraocular lenses (IOLs) are produced using a

combination of steps, which increase the pull strength



between the fixation member of the IOL and the optic of

the IOL without requiring sophisticated high frequency

corona discharge activation, plasma activation or other

exotic activation of the fixation member or primer coating

of the fixation member. The silicone polymeric optic

members can be formed, for example, moulded, without

recesses to accommodate the fixation members. Such

recesses can be formed and provided with a quantity of

silicone polymeric material precursor composition after

the optic members are produced. The fixation members

are then placed in the recesses and secured to the optic

members.

USA

Accession no.809891


SILICONE RUBBER COMPOSITIONS, THEIRPREPARATION AND USE IN HIGH-VOLTAGEELECTRICAL INSULATION CONTEXTSMeguriya N; Azechi S; Sekiguchi S


Disclosed is a thixotropic silicone rubber composition

comprising (A) an organopolysiloxane having, on

average, at least two alkenyl groups in a molecule and a

degree of polymerisation of up to 1,200, (B) a liquid

organohydrogenpolysiloxane having at least two

hydrogen atoms each attached to a silicon atom, (C)

aluminium hydroxide, (D) an addition reaction catalyst,

(E) a thixotropic agent and, optionally, (F) a tackifier. It

cures at room or elevated temperature into a silicone

rubber having high strength and electrical insulating

properties sufficient to serve as a high-voltage electrical

insulator. The composition is so thixotropic that it may

be used to repair chipped portions of insulators.



Accession no.808483

Item 18Macromolecular Materials and Engineering

Vols.284-5, Dec.2000, p.76-80

RUBBER PROCESSING WITH GAS-ASSISTEDINJECTION MOULDING (R-GAIM)Haberstroh E; Wehr H

IKV

Gas-assisted injection moulding was used to produce

hollow parts made of rubber (EPDM) and liquid silicon

rubber (LSR). The technique could be applied more easily

to LSR moulding than to the processing of EPDM

compounds used in this study. The gas needle and gas

injection area needed to be adapted to the processing

characteristics of the rubber in injection moulding. Further

studies will include the determination of the basic

requirements for mould design, the refinement of the

process control, different gas-assisted injection moulding

variants, limitations of the process and necessary material

characteristics. 14 refs.


WESTERN EUROPE

Accession no.807879

Item 19Composites Science & Technology

61, No.3, 2001, p.453-8

STUDY OF THE FEASIBILITY OF AMONOBLOCK RACING MOTORCYCLE RIMLegrand M; Ngoc Q A P

ENSAM

Details are given of the use of silicone rubber tools for

manufacturing the monoblock of a racing motorcycle. The

tool is made by vulcanising and inflating uncured sheets

of silicone rubber inside a forming mould. During cooling

these tools are regulated under a controlled pressure in

order to obtain an optimal pressing. 5 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE;

WESTERN EUROPE

Accession no.807674

Item 20Journal of Applied Polymer Science

79, No.12, 21st March 2001, p.2251-7

CHARACTERISTICS OF SURFACEWETTABILITY AND HYDROPHOBICITY ANDRECOVERY ABILITY OF EPDM RUBBER ANDSILICONE RUBBER FOR POLYMERINSULATORSJin Kuk Kim; In-Hwan Kim

Gyeongsang,National University

Test slabs of EPDM and silicone rubber were assessed

for long-term pollution resistance by subjecting the slabs

to a surface corona ageing treatment. The results obtained

showed good hydrophobicity of these materials and their

transfer of the contaminant layer deposited on the shed

surface of the insulator. The EPDM and silicone rubbers

are polymers of low density and they maintain significant

resistance to attack by oxygen and ozone. This study

measured the contact angle between water droplets and

other materials to determine the hydrophobicity and

recovery ability of these synthetic polymers. Surface

morphology was also studied in order to obtain a visual

confirmation of the migration phenomena. 15 refs.

SOUTH KOREA

Accession no.807404

Item 21Revista de Plasticos Modernos

79, No.527, May 2000, p.582-8

Spanish

NEW GAS PERMEABLE HYDROGELS FORPROLONGED USE CONTACT LENSES



Lasagabaster A; Moreno F; Rodriguez M A; de la

Orden M U

Madrid,Universidad Complutense

Problems of corneal damage caused by the prolonged

wear of contact lenses are discussed, and developments

in highly oxygen permeable polymeric hydrogels aimed

at overcoming such problems are examined.

Consideration is given to the oxygen permeability,

mechanical properties, wettability and resistance to lipid

deposition of hydrogels based on a number of polymers,

with particular reference to silicone polymers

commercially used in the manufacture of contact lenses.

15 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN;

WESTERN EUROPE

Accession no.807118

Item 22Analytical Chemistry

73, No.1, 1st Jan.2001, p.8-12

MICROMOSAIC IMMUNOASSAYSBernard A; Michel B; Delamarche E

IBM Research Division

Miniaturised mosaic immunoassays were developed

based on patterning lines of antigens onto a surface

(polydimethylsiloxane) by means of a microfluidic

network. Solutions to be analysed were delivered by the

channels of a second microfluidic network across thepattern of antigens. Specific binding of the target

antibodies with their immobilised antigens on the surface

resulted in a mosaic of binding events that could readily

be visualised in one screening using fluorescence. It was

thus possible to screen solutions for antibodies in a

combinatorial manner with great economy of reagents and

at a high degree of miniaturisation. Such mosaic-format

immunoassays were compatible with the sensitivity and

reliability required for immunodiagnostic methods. 27

refs.

SWITZERLAND; WESTERN EUROPE

Accession no.805159

Item 23Journal of Biomedical Materials Research

55, No.1, April 2001, p.33-9

IN VITRO BIOCOMPATIBILITY ASSESSMENTOF NATURALLY DERIVED AND SYNTHETICBIOMATERIALS USING NORMAL HUMANUROTHELIAL CELLSPariente J-L; Kim B-S; Atala A

Boston,Harvard Medical School

A primary normal human urothelial cell culture was used

to evaluate the in vitro biocompatibility of natural and

polymeric biomaterials. The cell viability, metabolic

activity, apoptotic properties and DNA-synthesis activity

were measured to determine cytotoxicity and bioactive

effects. Data are presented for polylactic acid,

polyglycolic acid, lactic acid-glycolic acid copolymers

and silicone polymers. 39 refs.

USA

Accession no.804585

Item 24Journal of Materials Science. Materials in Medicine

12, No.1, Jan.2001, p.15-21

DESIGN OF A SIMULATED URETHRA MODELFOR THE QUANTITATIVE ASSESSMENT OFURINARY CATHETER LUBRICITYJones D S; Garvin C P; Gorman S P

Belfast,Queen’s University

Details are given of the development of an in vitro urethral

model to characterise and compare the insertion and

removal properties of commercially available intermittent

catheters. The tensile properties of the silicone catheters

was also evaluated. 16 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; UK;

WESTERN EUROPE

Accession no.804576

Item 25Plastiques & Elastomeres Magazine

52, No.6, Aug./Sept.2000, p.14/7

French

TEXTILE COATINGDesne F

Rhodia Silicones

The use of silicone rubbers in the coating of fabrics for

clothing and automotive air bags is discussed, and

reference is made to developments by Rhodia Silicones

in Rhodorsil and Silbione silicone rubbers for use in such

applications.


WESTERN EUROPE

Accession no.803934

Item 26Plastiques & Elastomeres Magazine

52, No.6, Aug./Sept.2000, p.8-11

French

SURVEY OF SILICONE ELASTOMERSGouin F

Consideration is given to the vulcanisation, processing,

properties and applications of silicone rubbers, and

reference is made to some developments by Dow Corning,

Rhodia and Wacker in silicone rubbers and platinum

curing agents.

RHODIA SILICONES; WACKER SILICONES;

GESSIL; DOW CORNING CORP.EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE;

GERMANY; USA; WESTERN EUROPE

Accession no.803932



Item 27Adhasion Kleben & Dichten

42, No.4, 1998, p.40

German

SEALING DEVICES FOR PLUG-INCONNECTIONS

Under the brand name GelTek the firm Raychem from

Ottobrunn has brought out seals that are suitable for

sealing plug-in connections in motor vehicles, especially

for the new generation of miniaturised, high-pole plug-in

connections with a narrow contact gap. These seals are

based on a molecularly cross-linked silicon gel jointing

compound. This article also looks at wire contacts and

production of cable trees. Additional sealants are not

required. With slight pressure the gel seals joints

immediately making them watertight.

RAYCHEMEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.803787

Item 28Journal of Applied Medical Polymers

4, No.2, Autumn 2000, p.81-7

MECHANICAL CHARACTERISATION OFSILICONE ELASTOMER FOR USE IN AMEDICAL DEVICESarnowski E

Sulzer Carbomedics Inc.

A report is presented on the development of a set of

constitutive models to account for softening in silicone

rubbers for heart valve prostheses. These models were

distributed throughout a finite element mesh and used in

the design of a heart valve. A comparison was made of

the maximum predicted stress with data obtained from in

load-controlled fatigue testing in order to predict the

service life of the designs and a fatigue specimen

designed, analysed and tested to provide fatigue-lifetime

data. 10 refs.

USA

Accession no.803436

Item 29Antec 2000.Conference proceedings.

Orlando, Fl., 7th-11th May, 2000, paper 534

CATHETER DESIGNED TO GIVE IMMEDIATE,PAINLESS, OUT-PATIENT RELIEF TO BPHSUFFERERSCzuba L

Herbst LaZar Bell Inc.

(SPE)

The development of a silicone rubber catheter for the

treatment of benign prostatic hyperplasia is described. The

catheter is used to introduce a microwave antenna into

the affected area, and consists of multi-walled tubing to

provide cooling, and has a compression balloon with a

fixed outside diameter to create a biological stent in the

affected area. 3 refs.

USA

Accession no.803381



POLYURETHANE AND SILICONE AS NON-ALLERGENIC ALTERNATIVES TO LATEX FORMEDICAL BALLOONSShah T M

Polyzen Inc.

(SPE)

Polyurethanes and polysilicones have been developed for

medical applications which match the mechanical and

physical properties of natural latex, and are not allergenic.

They also have enhanced chemical resistance and reduced

UV sensitivity. Products may be shaped by dip moulding,

using a heated mandrel, the polymers being dissolved in

suitable solvents. These polymers are particularly suitable

for the production of low pressure medical balloons.

Accession no.803379

Item 31Journal of Biomedical Materials Research (Applied

Biomaterials)

53, No.6, 2000, p.646-50

TEXTURED POLYDIMETHYLSILOXANEELASTOMERS IN THE HUMAN LARYNX:SAFETY AND EFFICIENCY OF USESittel C; Thumfart W F; Pototschnig C; Wittekindt C;

Eckel H E

Koln,Universitat; Innsbruck,Universitat

The systematic application and long-term results of

vulcanised polydimethylsiloxane (PDMS) particles in the

treatment of glottic insufficiency in the human larynx is

reported. Of ten patients treated with PDMS in the early

1990s, seven patients can be retrieved for reevaluation.

Laryngeal function is assessed by videostroboscopy,

expert rating and further characterised by the objective

parameters of voice profile and maximum phonation time.

All patients are asked for their personal impression of

the results. Mean follow-up time is 88.4 months. Glottic

closure is complete in five of seven patients. There are

no signs of granuloma formation or other pathologic

changes of the injected vocal folds. In four cases, voices

are rated normal or near-normal; two voices rated as fair;

one usable. All the patients report significant and lasting

voice improvement. None of the patients report any

problems related to PDMS. PDMS particles provide

permanent augmentation of human vocal fold volume

without complications. Their use is a valuable and safe

alternative when a definitive one-step procedure seems

advantageous. However, further studies are needed to



assess voice improvement in comparison to other

materials. 34 refs.

AUSTRIA; EUROPEAN COMMUNITY; EUROPEAN UNION;

GERMANY; WESTERN EUROPE

Accession no.802623

Item 32Iranian Polymer Journal

9, No.3, July 2000, p.163-7

APPLICATION OF POLYDIMETHYLSILOXANEAS ADSORBENT FOR DETECTION OFALIPHATIC HYDROCARBON COMPOUNDSVAPOURS USING QUARTZ CRYSTALMICROBALANCE (QCM)Mirmohseni A; Hassanzadeh V

Tabriz,University

Polydimethylsiloxane (PDMS) is used as adsorbent for

detection and determination of some aliphatic hydro-

carbons such as n-pentane, n-hexane, n-heptane and

cyclohexane. The contamination of environment by

these volatile organic compounds is a serious problem

due to their potential human toxicity. Therefore, analysis

of these compounds has become more and more

important and various techniques have been developed

to target this aim. A thin layer of PDMS is coated at the

surface of an AT-cut gold-coated quartz crystal electrodes

and a sensor based on the technique of quartz crystal

microbalance is developed for the detection of these

organic vapours. Detection is based on the measurement

of the frequency shifts due to the adsorption of the

organic compounds on the polymer film. Calibration

graphs are constructed by plotting the frequency changes

(delta F/Hz) against the concentration of organic

compounds. Using this method, the detection of these

organic vapours is successfully carried out at parts per

million concentrations. 22 refs.

IRAN

Accession no.802521

Item 33Patent Number: US 6011105 A 20000104

FLAME RETARDANT SILICON RUBBERCOMPOSITION FOR COATING ELECTRICALWIRE AND CABLEOta K; Hirai K


The above composition comprises: (a) polyorgano-

siloxane with a given average compositional formula, (b)

microparticulate silica having a mean primary particle

diameter of at least 18 nm and a specific surface area no

greater than 95 sq.m./g, (c) platinum or a platinum

compound, (d) triazole compound, and (e) methyl-

substituted benzoyl peroxide.

JAPAN

Accession no.800949


HEAT FIXING ROLLSMiyakoshi M; Shudo S; Tomizawa N; Kondou T


These include a silicone rubber layer on a cylindrical metal

mandrel having a penetration of at least 10, according to

ASTM D1403, and a fluoropolymer layer thereon. The

silicone rubber layer is obtained by moulding and curing

an addition reaction type liquid silicone rubber

composition to the mandrel. The roller provides a

sufficient nip width under low pressure, improved

abrasion resistance, long-lasting toner release, and a

satisfactory fixing function even at a high speed over a

long period of time.

JAPAN; USA

Accession no.800308

Item 35European Rubber Journal

183, No.1, Jan.2001, p.18-9

JAMAK TAKES ON TRICO IN WIPER-BLADECONTESTBegin S

Premium-priced wiper blades produced by Jamak

Fabrication and Trico Products will go head-to-head in

the US automotive aftermarket. Jamak is touting its single-edge silicone blade it began producing in January for

Texaco. The company claims the Havoline blades last two

to three times as long as traditional, organic rubber blades

thanks to their resistance to ozone, UV rays and extreme

heat and cold. Trico insists its Teflon Blade gives superior

wiper performance. Trico’s blade has a beige strip on the

wiping edge to indicate the presence of Teflon that is

coextruded with NR.

JAMAK FABRICATION INC.; TRICO PRODUCTS

CORP.USA

Accession no.799078

Item 36Polymers for Advanced Technologies

11, Nos.8-12, Aug./Dec.2000, p.460-7

POLYSILANE LIGHT-EMITTING DIODESSuzuki H; Hoshino S; Furukawa K; Ebata K; Chien-

Hua Yuan; Bleyl I

NTT Basic Research Laboratories

The development of polysilane light-emitting diodes

(LEDs) made from a diaryl polysilane, poly(bis(p-n-

butylphenyl)silane)(PBPS), is described and comparison

is made with LEDs prepared using a conventional

polysilane, polymethylphenylsilane. In contrast to LEDs

based on conventional polysilanes in which a weak UV

electroluminescence(EL) was detected either with a strong

broad visible EL or only at low temps., room temp. pure



near-UV EL was observed with a quantum efficiency of

0.1% photons/electron with an electron injecting Al

electrode in PBPS-LEDs. The spectroscopic, electronic

and structural properties of PBPS were examined and the

improvements observed in the EL characteristics were

ascribed to them. The possible future direction of

polysilane LED research is considered and other potential

optoelectronic applications of polysilanes to the active

medium of lasers are mentioned. 33 refs. (5th International

Symposium on Polymers for Advanced Technologies,

Tokyo, Aug./Sept.1999)

JAPAN

Accession no.798024


ADDITIVE FOR THE PREVENTION OFNITROSAMINE FORMATION IN SILICONEARTICLESLewis L N; Jeram E M

General Electric Co.

The present invention relates to a method for making

nitrosamine-free silicone articles by treating the mixture

of vinyl containing organopolysiloxane and filler with

hindered phenols, a nitrosamine-free composition and a

nitrosamine-free article made therefrom. A preferred

nitrosamine-free moulded article is a baby bottle nipple.

USA

Accession no.797938


PROCESS FOR THE SEALING COMPONENTSEXPOSED TO AGGRESSIVE FUNCTIONALFLUIDS AND RTV SILICONE COMPOSITIONSSUITABLE FOR USE THEREINDavis T D

Wacker Silicones Corp.

RTV-1 silicone sealants resistant to deterioration in the

presence of aggressive functional fluids are prepared from

an organopolysiloxane component comprising a major

amount of silanol-functional organopolysiloxane, a

primary or secondary amine-functional crosslinker, and

both iron oxide and magnesium oxide, optionally together

with auxiliary fillers, adhesion promoters, catalysts, and

customary additives. The gasket materials are particularly

useful in axle and transaxle seals exposed to fuel

efficiency-promoting aggressive lubricants.

USA

Accession no.797924

Item 39Polymer Preprints. Volume 40. Number 2. August

1999. Conference proceedings.

New Orleans, La., August 1999, p.799-800

SYNTHESIS OF NITRIC OXIDE RELEASINGSILICONE RUBBERS FOR BIOMEDICALAPPLICATIONSZhang H; Schoenfisch M H; Meyerhoff M E

Michigan,University

(ACS,Div.of Polymer Chemistry)

Two approaches for preparing nitric oxide (NO) releasing

silicone rubber films are reported. Silicone rubber (SR)

is widely used in industry, consumer and medical products

for which NO release may prove useful. It is shown that

diazeniumdiolates can be anchored onto either a

polysiloxane matrix or fumed silica filler to fabricate NO

releasing silicone rubbers. 14 refs.

USA

Accession no.797268

Item 40Chemical Marketing Reporter

258, No.24, 11th Dec.2000, p.FR24

SILICONE PRODUCERS ROLL OUTINVESTMENTSBoswell C

There are eight major producers of silicones, with Dow

Corning the largest with a 36% share of the global market,

by value, in 1998. Between 1995 and 1998, the global

market for silicones and silanes grew at an average annual

rate of 6% from 5.7bn to 6.7bn US dollars. The greatestgrowth will be in Asia, where global producers are making

major investments in preparation. The most recent is a

joint venture announced by GE Silicones and Shin-Etsu

in October which will build a facility for the production

of silane monomers and siloxane intermediates at a site

in Southeast Asia. The US market for silicones and silanes

is valued at 2.065bn US dollars based on 1998 estimates.

WORLD

Accession no.797180


SILICONE RUBBER COMPOSITIONS FORHIGH-VOLTAGE ELECTRICAL INSULATORSAND POLYMERIC BUSHINGSMeguriya N; Azechi S; Sekiguchi S; Yoshida T


A silicone rubber composition is obtained by blending

(A) 100 parts by weight of an organopolysiloxane

composition of the addition reaction curing type with (B)

about 30 to 400 parts by weight of aluminium hydroxide,

which has been surface treated with an organosilane or

organosilazane substantially free of an aliphatic

unsaturated group or a partial hydrolysate thereof so that

the aluminium hydroxide has 0.01 to 2% by weight of

carbon affixed thereto. The composition maintains

silicone rubber properties even though it is loaded with

large amounts of aluminium hydroxide. It cures into a



silicone rubber having improved high-voltage electrical

insulating properties and thus is suited for use as high-

voltage electrical insulators.

JAPAN; USA

Accession no.796589

Item 42Silicones in Coatings II. Conference proceedings.

Florida, USA, 24th-26th March 1998, paper 35

NEW GENERATION OF SILICONEELASTOMERS FOR AIRBAG COATINGSBohin F; Pouchelon A; Surprenant R

Rhodia Silicones

(Paint Research Association)

When airbag technology appeared on an industrial scale

in the middle of the 1980s, the first bags were neoprene

coated. Although neoprene met initially the performance

requirements of airbags, its efficiency was questionable

in the long term. By the end of the 1980s a new trend

appeared: silicone-coated fabrics. In the early 1990s,

specific liquid silicone rubber (RTV-2) was developed

for airbag applications. Being self-bonding onto the fibre,

they require the use of solvent during the coating process.

In 1996, a new generation of silicone elastomers for

coating was launched onto the European market.

Specifically designed to meet the airbag market evolution,

these new products provide specific rheological properties

allowing very thin coating without any change of the

technology or any use of a solvent. This of course allows

significant cost reductions for the customer. Offering

improved thermal protection to the fabric, they are very

well adapted to the new generation of airbag inflators

arising from the market. Their specific properties also

provides a 100% increase of the fabric tear strength. 6

refs.

USA

Accession no.795798



BIOPROTECTING ORGANOSILICONECOATINGSVoronkov M; Chernov N

Irkutsk,Institute; Russian Academy of Sciences


To protect materials and parts against contamination

various polymer coatings are used, containing fungicides,

bactericides or other agents. Protective coatings are

known, based on organosilicone polymers modified with

heteroorganic compounds with antimicrobial activity,

particularly organotin compounds of the R3SnX type.

Heteroorganic fungicides may also be introduced into

hydrolysates of Si(OC2H5)4 or Ti(OC2H5)4, which are

used for clarification of optical glasses. Despite resistance

to bioovergrowth, physicochemical, mechanical and

protective properties of coatings containing heteroorganic

and inorganic fungicides degrade during operation. With

time they completely lose their fungicidal activity under

the action of adverse climatic factors or more or less

corrosive environment. This refers also to a great majority

of the known fungicidal and bactericidal coatings on

organic binders. Biocidal coatings based on polydiorgano-

siloxanes with terminal triorganostannyloxy groups were

patented. However these coatings are short-lived; they

are not chemically bound to the surface, and the OSnR3

terminal fragments are hydrolytically unstable. Extensive

and systematic studies are performed on carbofunctional

organosilicone monomers and resultant coatings. 73 refs.

RUSSIA

Accession no.795794



MATRIX ASSISTED PULSED LASEREVAPORATION (MAPLE): APPLICATIONSWITH FUNCTIONALISED POLYSILOXANEMATERIALSMcGill R A; Chrisey D B; Mlsna T E; Pique A

US,Naval Research Laboratory


A novel polymer processing technique, matrix-assisted

pulsed laser evaporation (MAPLE), for the deposition of

polysiloxane and other materials, as ultra-thin and uniform

coatings has been developed. The technique involves

directing a pulsed excimer laser beam onto a frozen matrix

target composed of the polymer material in a solvent. The

process gently lifts polymeric material into the gas phase

with no apparent decomposition. A plume of material is

developed normal to the target, and a substrate positioned

incident to this plume is coated with the polymer. The

MAPLE technique offers a number of features that are

difficult to achieve with other polymer coating techniques,

including nanometer to micron thickness range, sub

monolayer thickness precision, high uniformity,

applicability to photosensitive materials and patterning

of surfaces. Highly functionalised polysiloxanes are

synthesised and deposited on a range of substrates by the

MAPLE technique, and characterised by IR spectroscopy

and optical microscopy. High quality, uniform and

adherent polysiloxane coatings are produced by the

optimised MAPLE technique. The physicochemical

properties of the coating are unaffected by the process,

and precise thickness control of the coating is straight-

forward. 26 refs.

USA

Accession no.795781


MOTHER MOLD-FORMING SILICONE



RUBBER COMPOSITION AND MOTHER MOLDOBTAINABLE THEREFROMMiyoshi K; Tanaka K


In a silicone rubber composition comprising an

organopolysiloxane as a base polymer, 0.1 to 50 parts by

weight of a modified silicone fluid having a melting point

of up to 100C and a refractive index difference of 0.01 to

0.05 from the base polymer is blended per 100 parts by

weight of the composition. The composition is cast and

cured to form a mother mould, which maintains parting

properties over a long term.



Accession no.795412

Item 46158th. ACS Rubber Division Meeting - Fall 2000.

Conference preprints.

Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 116

PEROXIDE CROSSLINKING OF SILICONECOMPOUNDSNiijhof L B G M; Cubera M

Akzo Nobel Polymer Chemicals BV; Akzo Nobel

polymer Chemicals LLS

(ACS,Rubber Div.)

A review is presented of the crosslinking of silicone

compounds by organic peroxides, with particularemphasis on the different peroxide classes available and

their cure characteristics in various silicone formulations.

Processing guidelines are included and the influence of

certain compounding ingredients is addressed. A

comparison is also made between platinum catalysed cure

systems and peroxide cure systems. 9 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION;

NETHERLANDS; USA; WESTERN EUROPE

Accession no.794212



SIMULATION OF THE FILLING AND CURINGPHASE IN INJECTION MOLDING OF LIQUIDSILICONE RUBBER (LSR)Haberstroh E; Michaeli W; Henze E

Aachen,Institut fur Kunststoffverarbeitung; GE Bayer

Silicones GmbH & Co.KG

(SPE)

A model was developed for the filling and curing phases

in the injection moulding of two-part liquid silicone

rubbers, from considerations of the specific volume, the

cavity pressure and the material temperature. The filling

phase was modelled using 2-1/2-D simulation software

based on finite element methods, in which over 90% of

the cavity was filled under volume flow controlled

conditions and the balance by the thermal expansion of

the material. Curing, which is thickness-dependent, is

assumed to be complete when an average degree of curing

of 95% over the wall thickness is achieved, with a

minimum degree of 75%. 10 refs.


WESTERN EUROPE

Accession no.793821

Item 48High Performance Elastomers 2000. Conference

proceedings.

Berlin, Germany, 10th-11th Oct.2000, paper 13

ELASTOMERIC SILICONE ADHESIVES FORAUTOMOTIVE ENGINE GASKETS ANDSEALINGLoubet O

Rhodia Silicones

(Rapra Technology Ltd.; European Rubber Journal)

With an average growth of more than 10% each year,

silicone elastomers are used more and more in the

automotive industry, especially for gasketing applications

requiring thermal and chemical resistance. Today, Rhodia

Silicones with a wide range of gasketing technologies,

i.e. silk-screened gasket, injected gasket, formed-in-place-

gasket (FIPG) and cured-in-place-gasket (CIPG), has

reached a leading position in the automotive sealing

industry. The high level of performance of silicone

elastomers is achieved with an additional ease of

processability of the liquid silicone, thus making it the

economical solution for bonding and sealing automotive

parts. Building on the company’s experience of over 30

years in automotive gasketing, the company achieves the

innovation needs of customers through heat curing

elastomers (HCR), RTV1 and RTV2 technologies. A new

generation of elastomeric silicone adhesives targeted for

plastic parts has been developed. 21 refs.


WESTERN EUROPE

Accession no.792375

Item 49High Performance Elastomers 2000. Conference

proceedings.

Berlin, Germany, 10th-11th Oct.2000, paper 12

LIQUID SILICONE RUBBER. THE UNIQUEHIGH PERFORMANCE MATERIAL INAPPLICATIONS AND PROCESSINGTrumm C

Dow Corning GmbH

(Rapra Technology Ltd.; European Rubber Journal)

Injection moulding of liquid silicone rubbers is becoming

increasingly important. One reason for this is the increased

performance requirements of the finished articles. In

addition, more and more producers of rubber parts are

seeing benefits in the high level of automation and



productivity. Silastic liquid silicone rubber was pioneered

by Dow Corning and introduced to the rubber fabrication

marketplace in the late 1970s. Today the processing and

product advantages of LSR are exploited in many existing

and new applications. A broad product line is available

both for general applications and certain LSRs tailored

for specific requirements. LSRs are liquids with

viscosities that vary from easily pourable to pastes. These

two component materials are mostly used in a 1:1 ratio

and consist of polysiloxane polymers or copolymers that

are vulcanised above 120 deg.C by polyaddition. Aspects

covered include technology advantages, application

examples, LSR rheology, injection moulding of LSR, and

properties and mould design.


WESTERN EUROPE

Accession no.792374


27, No.9, 2000, p.T/24-5

HEAT RESISTANCE OF SILICONE RUBBERFILLED WITH HEAT-EXPANDED GRAPHITEDedov A V; Nazarov V G

Tekhindustriya-M Closed Joint Stock Co.

The influence is investigated of dispersed heat-expanded

graphite on the temperature dependences of the strength

of composites based on silicone rubber. It was established

that heating of the material increases the mobility of the

segments of the macromolecules and the relaxation rate,

which leads to a more uniform distribution of the

mechanical load and to an increase in the strength of the

composite. Treatment of the composite at 200 degrees C

for 2 hours was found to be the optimum, and the highest

strength with such treatment was found to be that of a

composite containing 20 wt.% heat-expanded graphite. 4

refs. Translation of Kauchuk i Rezina, No.2, 2000, p.8.

RUSSIA

Accession no.791813

Item 51Plastics, Rubber and Composites

29, No.5, 2000, p.229-34

EFFECT OF CAVITY PRESSURE ONCROSSLINK DENSITY OF INJECTIONMOULDED SILICONE RUBBERBarbaroux M; Regnier G; Verdu J

Dow Corning Healthcare Industries; Ecole Nationale

Superieure d’Arts et Metiers

The effects of injection moulding conditions

(temperatures 120 and 160 deg.C, pressures from 5 to 50

MPa) on the crosslink density of the resulting parts

(determined from equilibrium solvent swelling

experiments) are studied for an elastomer of the liquid

silicone rubber type, in which crosslinking results from

platinum catalysed vinyl-silane addition. It is shown,

unexpectedly, that a pressure increase leads to an increase

in the cure rate, despite the unfavourable effect of pressure

on viscosity. 22 refs.


WESTERN EUROPE

Accession no.789932


KEY PAD WITH RIGID RESIN KEY TOPNishi K

Polymatech Co.Ltd.

A key pad having a rigid key top is disclosed, which is

not subject to key top detachment or dislocation and does

not require key detachment prevention means, such as a

collar. The key top is adhered to a silicone rubber key

pad with a silicone base adhesive by providing a urethane

base adhesion substrate layer on the back of the key top.

EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN

EUROPE-GENERAL

Accession no.787625


POLYVINYLSILOXANE IMPRESSIONMATERIALFiedler J H

Dentsply DeTrey GmbH

Improved two component polymerisable polyorgano-

siloxane compositions are described, particularly for use

in making dental impressions, having improved tear

strength and wettability. Improved tear strength results from

inclusion of a quadri-functional polysiloxane having a vinyl

content of 0.16 to 0.24 m-mole/g. Working time is

maintained by including sufficient amounts of a retarder

composition that delays onset of the vinyl polymerisation.

Wettability is improved by including a surfactant resulting

in a surface contact angle with water at three minutes of

less than 50 degrees. The surfactant chosen has an HLB of

8-11, such that the wetting contact angle is achieved within

less than two minutes and remains wetting throughout the

working time of the impression taking, substantially

improving impression quality. A low viscosity impression

material is provided and includes a base component and a

catalyst component. Both components are siloxane-based

materials.


WESTERN EUROPE

Accession no.787417

Item 54IRC 2000. Conference proceedings.

Helsinki, Finland, 13th-15th June 2000, paper 79

SILICONE RUBBER: INNOVATIONS THATCOMPETE



Dietl S

Wacker Chemie GmbH

(Nordic Council of Rubber Technology)

The developments in silicone rubber described open up

possibilities of higher productivity and improved quality.

The concept of fast peroxide-free curing/no post cure and

self-bonding silicone rubber materials provide new and

versatile solutions to the silicone rubber and plastic

processors.


WESTERN EUROPE

Accession no.787111


SILICONE COMPOSITION WITH IMPROVEDHIGH TEMPERATURE TOLERANCETkaczyk J E; Klug F J; Amarasekera J; Sumpter C A


A high temperature insulating composite composition

comprising at least one ground silicate mineral and at least

one silicone polymer. The at least one ground silicate

mineral is at least one mineral selected from the group of

olivine group; garnet group; aluminosilicates; ring

silicates; chain silicates; and sheet silicates. The high

temperature insulating material has particular usefulness

for insulating electrical wires.

USA

Accession no.786716


78, No.4, 24th October, 2000, p.724-31

SILICON-BASED MATERIALS PREPARED BYIPN FORMATION AND THEIR PROPERTIESTsumura M; Iwahara T

Kaneka Corp.

Silicon-based interpenetrating networks (IPNs) were

prepared from a ladder silsesquioxane oligomer and a

polycarbosilane by hydrosilylation polymerisation of

bifunctional Si-H and Si-vinyl monomers. This was

followed by melt and compression moulding of the B-

staged resin. Materials of various shapes were formed

and the flexural modulus and Izod impact strength were

evaluated, and found to be larger than those for each

component. The thermal, electrical and optical properties

were also measured. 18 refs.

JAPAN

Accession no.786476

Item 57Iranian Journal of Polymer Science & Technology

13, No.1, Spring 2000, p.1-7

Persian

PRODUCTION OF A POLYMERIC OCULAR

PROSTHESIS FOR GLAUCOMA THERAPYJafary M R; Mirzadeh H; Eslami Y; Amini H

Amirkabir,University of Technology; Tehran University

of Medical Science

The manufacture of moulds by electroforming and

preparation of prostheses with both the plate and connecting

tube made from silicone rubber are described. The results

of in vitro tests performed to evaluate the biocompatibility

of the prostheses are also reported. 18 refs.

IRAN

Accession no.786386


SILICONE RUBBER MOLDINGCOMPOSITIONS AND METHOD FORPRODUCING SILICONE RUBBER MOLDEDPARTSHayashida O


In a silicone rubber composition comprising an

organopolysiloxane, reinforcing silica, and a curing agent,

an ester wax, typically having a melting point of 40 to

150C is blended as an abherent. When the composition is

moulded in a mould, the flow of the composition in the

mould and the parting of the cured silicone rubber from

the mould are significantly improved.

JAPAN; USA

Accession no.786311


RADIATION-CURABLE SILICONE RUBBERCOMPOSITIONOkinoshima H; Kashiwagi T; Yamaguchi S


A radiation-curable silicone rubber composition is provided

which includes: (A) a specific organopolysiloxane having

radiation-sensitive (meth)acryloyl groups at the both

terminals of the molecular chain, (B) a photosensitiser; (C)

a tetraalkoxysilane or a partial hydrolysis-condensation

product thereof; and (D) optionally together with a specific

organic titanium compound. This composition is curable

upon irradiation by ultraviolet rays for a short time and

exhibits adhesion quickly. Hence, it is useful for the

bonding, coating and potting of various substrates. This

composition also has a relatively weak adhesion

immediately after curing, and can be peeled from the

substrate with ease for a while. Hence, it is also suited for

uses where repair is required. Because of a high curing

rate, it can be effective for, e.g. making a process short,

improving productivity and saving energy in the

manufacture of electric and electronic parts.

JAPAN; USA

Accession no.786163




182, No.9, Sept.2000, p.28/31

SILICONE GRADES FOR CO-MOULDINGShaw D

Wacker-Chemie has developed a new grade of liquid

silicone elastomer, Elastosil LR. The benefit of this

material is that it offers easy mould release after a short

period of elevated temperatures, such as the cure cycle,

but then goes on to develop good bond strengths over a

period of 24 hours or so. This makes it ideal for

overmoulding processes or where a thin layer of silicone

needs to be applied over another substrate. The material

bonds to thermoplastics, although not all. Applications

include water-resistant mobile phones, shower heads and

electrical connectors. The company is introducing a high

temperature vulcanisation grade of the self-adhesive

silicone later this year which has been developed for

adhesion to metals. One potential application is for

exhaust pipe mounts used in cars.


WESTERN EUROPE

Accession no.785116


51, No.3, 5th Sept. 2000, p.408-12

IN VITRO FORMATION OF OROPHARYNGEALBIOFILMS ON SILICONE RUBBER TREATEDWITH A PALLADIUM/TIN SALT MIXTUREDijk F; Westerhof M; Busscher H J; van Luyn M J A;

van der Mei H C

Groningen,University

Silicone rubber voice prostheses were treated with a

colloidal palladium/tin solution to form a thin metal coat

intended to discourage biofilm formation. The effect of

the coating on airflow resistance and cytotoxicity was

examined. 28 refs.


NETHERLANDS; WESTERN EUROPE

Accession no.782970


METHOD OF FORMING ARTIFICIAL ROCKSHEATHINGBahr G J

Apparatus and method for the fabrication of semi-flexible

artificial rock sheathing are disclosed. A one-coat silicone

elastomer is brushed or sprayed on the surface of a

substantially flat natural rock formation to form a mould

that is adhered to a wood-framed fibreglass cradle that

holds the shape of the mould. When removed from the

rock formation, the mould is sprayed with a thermoplastic

elastomer to form a semi-flexible rock sheathing having

the same characteristics as the natural rock surface from

which the mould was formed. After the materials are fully

cured, the sheathing sheet may be separated from the

mould and used for the fabrication of rock or rock

structures by attaching sheathing sheets to the exterior of

a framework, followed by cutting and forming different

shapes.

USA

Accession no.782380


COATED TEXTILE FABRICSBrookman L; Lawson D W

Dow Corning Ltd.

Disclosed is a coated textile fabric, which is useful for

fabricating automobile airbags. A surface of the textile

fabric is coated with first and second layers of

polyorganosiloxane-based elastomeric material, the first

layer being disposed between the textile surface and the

second layer. The polyorganosiloxane-based material of

the first layer exhibits an elongation at break of at least

400%. The polyorganosiloxane-based material of the

second layer exhibits a tear strength of at least 30 kN/m.

USA

Accession no.780295

Item 64Rubber World

222, No.3, June 2000, p.36/48

MULTI-COMPONENT INJECTION-MOULDINGOF RIGID-FLEXIBLE COMBINATIONSRonnewinkel C; Haberstroh E

Institut fur Kunststoffverarbeitung

Multi-component injection moulding offers ecological

and economical advantages. Combinations of rigid and

flexible materials are of major interest to the industry.

Due to their properties, curing rubbers and liquid silicone

rubbers allow extended applications of rigid-flexible

combinations and can substitute rubber-metal parts. The

examinations show a good adhesion strength between

thermoplastics and LSR, and between polyamide 6,12 and

X-NBR rubber. In order to find suitable mould concepts

for these material combinations, it will be demonstrated

how to use computer simulation for the analysis of

temperature distribution and curing rate. 12 refs.


WESTERN EUROPE

Accession no.780117

Item 65Rubber World

222, No.3, June 2000, p.26/35

NEW TRENDS IN SILICONE ELASTOMERTECHNOLOGY



Burkus F S; Amarasekera J

General Electric Co.,Silicones Div.

Siloxanes offer unique properties as elastomers and

therefore are being used in increasing amounts for such

applications. Liquid injection moulded silicone materials

have excellent physical and chemical properties which

make them suitable alternatives to standard millable and

pourable siloxane elastomers. New advances in liquid

injection moulded siloxane materials, including self-

bonding, low compression set and controlled force

deflection, address some previous issues that have

limited the use of these systems in certain applications.

Advances in mould design have enabled a two-shot ETP/

liquid injection moulded elastomer system to be

developed. 6 refs.

USA

Accession no.780116


29, No.22, 29th May 2000, p.22

MCGHAN MEDICAL GETS OK FOR SALINEIMPLANTSMoore M

McGhan Medical, a breast implant manufacturer, having

received government approval to keep saline-filled

implants on the market, will seek to get the near-ban on

silicone-gel implants lifted. A study on silicone implants

from the FDA shows that silicone implants often rupture

in women’s bodies without their knowing, but McGhan

says its implants are much stronger and better than the

devices studied in the report.

MCGHAN MEDICAL CORP.

USA

Accession no.780110


27, No.5, 2000, p.T/6-T/13. (Translation of Gummi

Fasern Kunststoffe, No. 3, 2000, p. 162)

PRODUCTION OF LARGE-DIMENSIONEDARTICLES FROM SILICONE ELASTOMERSKrell V

The production of large-dimensioned articles from high

temperature vulcanising silicone rubber and liquid silicone

rubbers is described, with respect to the processing

equipment, moulding tools, and processing techniques.

Examples are included of products produced by these

techniques, and include an outdoor terminal plug with

and without field control element, long rod insulators, a

lightening conductor, and an angled plug.


WESTERN EUROPE

Accession no.779949


27, No.4, 2000, p.T/25-T/28. (Translation of Kauchuk i

Rezina, No.6, 1999, p.8)

PRODUCTS MADE FROM POLYSILOXANESWITH A PROPERTY GRADIENTBritove V P; Yurkhanov V B; Nikolaev O O; Bogdanov

V V

St.Petersburg,State Technical University

It is demonstrated that it is possible to produce products

with different properties on their working surfaces, by a

combination of thermal and radiation vulcanisation

methods. In particular, the crosslinking of polysiloxanes

for use in medical applications, is discussed. The results

of modification by these combined vulcanisation

techniques are examined with reference to

physicomechanical properties. 8 refs.

RUSSIA

Accession no.779702

Item 69Advanced Composites Letters

9, No.2, 2000, p.115-23

ANALYSIS OF EXPLANTED SILICONE/SILICACOMPOSITE BREAST IMPLANTSBrandon H J; Young V L; Jerina K L; Wolf C J

Washington,University

The effect of implantation time on the physical,

mechanical and chemical properties of silicone rubber

(Silastic II)/silica gel breast implants was investigated and

the results compared with those for lot-matched control

(unimplanted) samples. In vivo duration times ranged

from 4 months to 10 years. The tensile strengths of explant

and control samples were determined using identical

testing protocols as were the tensile strengths of implants

extracted with hexane to remove non-crosslinked

silicones. Average molec.wts. between crosslinks were

determined by swelling measurements. 5 refs.

USA

Accession no.778727

Item 70Applied Organometallic Chemistry

14, No.6, June 2000, p.287-303

ORGANOSILICON ION-EXCHANGE ANDCOMPLEXING ADSORBENTSVoronkov M G; Vlasova N N; Pozhidaev Y N

Russian Academy of Sciences

Literature data concerning research organosilicon ion-

exchangers and complexing agents are summarised and

systematised. Data on organophilic organosilicon

adsorbents and sorption systems for chromatography are

not considered. 136 refs.

RUSSIA

Accession no.778015




Biomaterials)

53, No.3, 2000, p.267-75

FABRICATION OF MICROTEXTUREDMEMBRANES FOR CARDIAC MYOCYTEATTACHMENT AND ORIENTATIONDeutsch J; Motlagh D; Russell B; Desai T A

Illinois,University

Details are given of the preparation of microtextured

silicone membranes using photolithography and

microfabrication techniques. The attachment of cardiac

myocytes onto these membranes was investigated. 34 refs.

USA

Accession no.777781


COATING MATERIALMorita Y; Furukawa H; Aso T


A highly weather-resistant coating, which exhibits

excellent water resistance and water repellency, contains

a vinyl-type polymer having a pendant carbosiloxane

dendrimer structure. The coating is used on construction

materials, buildings and structures undercoated with an

organic coating material, automobiles, railroad rollingstock, ships, aircraft, bridges, commercial and industrial

plants and electrical and electronic instruments and

devices.



Accession no.777717


SILICONE RUBBER BASE COMPOUND FORELECTRICAL WIRE COATING, SILICONECOMPOSITION FOR ELECTRICAL WIRECOATING, AND PROCESS FOR THEPRODUCTION OF SILICONE RUBBER COATEDELECTRICAL WIREBaba K; Ota K


Disclosed is a silicone rubber base compound for electrical

wire coating such that when it is extruded using an

extruding machine having a variable screw with an L/D=10

and a die with a diameter of 1 mm attached thereto at a

barrel and head temperature of 70C, the per-minute extruder

output rate at a screw rotation speed of 100 rpm is not less

than 1.2 times the extruder output rate at a screw rotation

speed of 50 rpm. It may be obtained by compounding diacyl

organic peroxide consisting of carbon atoms, hydrogen

atoms and oxygen atoms with the silicone rubber base

compound for electrical wire coating.



Accession no.777716


PROTECTING ELECTRONIC COMPONENTS INACIDIC AND BASIC ENVIRONMENTPolak A J; Baker T L

Motorola Inc.

Electronic devices, which are protected by an organic

polymeric encapsulant and placed in a corrosive

environment, can have added protection by dispersing in

the encapsulant particles of a solid buffer which tend to

neutralise the effect of the corrosive agent. This approach

is quite effective when strong acids are the corrosive

agents and when solid acid-base buffers are dispersed in

the polymeric material. The encapsulant may be

elastomeric. Silicone elastomers containing solid acid-

base buffers are quite effective in protecting the

underlying electronic device from corrosion by strong

acids.

USA

Accession no.777524


SILICONE DIE ATTACH ADHESIVE, METHODFOR THE FABRICATION OFSEMICONDUCTOR DEVICES, ANDSEMICONDUCTOR DEVICESMitani O; Nakayoshi K; Tazawa R; Mine K


A silicone die attach adhesive is disclosed which

comprises a silicone composition which cures both

through the free radical reaction of acrylic-functional

organopolysiloxane as induced by exposure to high-

energy radiation and through the hydrosilylation reaction

between alkenyl-functional organopolysiloxane and

silicon-bonded hydrogen-functional organopolysiloxane.

Also disclosed is a fabrication method characterised by

mounting a semiconductor chip on a substrate or in a

package with the aforesaid silicone die attach adhesive

sandwiched between the semiconductor chip and substrate

or package, then inducing the free radical reaction of the

acrylic functional groups by exposing the die attach

adhesive to high energy radiation, and thereafter curing

the die attach adhesive by the hydrosilylation reaction. A

semiconductor device, characterised in that it has been

fabricated by the above-described method, is disclosed.

JAPAN

Accession no.774597




AQUEOUS SILICONE DISPERSIONSCROSSLINKABLE INTO ELASTOMERICSTATE BY DEHYDRATIONFeder M; Ulrich J

Rhone-Poulenc Chimie

The above dispersions comprise: (a) 100 pbw of an oil-

in-water emulsion of an alpha-omega-(dihydroxy)

polydiorganosiloxane stabilised with at least one anionic

or nonionic surface active agent, or mixture thereof, (b)

1-100 pbw of an hydroxylated silicone resin containing,

per molecule, at least two different recurring structural

units selected from a given group, the resin having a

hydroxyl group weight content of 0.1-10%, (c) 0-250 pbw

of a nonsiliceous inorganic filler, and (d) 0.01-3 pbw of a

metal curing catalyst compound. These dispersions have

a solids content of at least 40%.


WESTERN EUROPE

Accession no.774410


182, No.1, Jan.2000, p.21-4

TOUGH SERVICE CONDITIONS MEAN TOUGHELASTOMERSWhite L

Fluoroelastomer growth in the US of around 4%/year in

automotive uses is predicted in a recent market report.Dyneon’s base-resistant Fluorel BRE fluoroelastomers are

formulated to withstand the demanding conditions found

in basic and amine-containing environments, most notably

those involving new lubricating fluids in the automotive

industry. DuPont Dow Elastomers’ range, Viton Extreme

ETP, is described as suitable for severe sealing

applications requiring a combination of heat, fluids and

base resistance with low-temperature flexibility. Makers

of silicone elastomers and HNBR have grades which are

suitable for various fuel-contact applications.

USA

Accession no.772741


26, No.5, 1999, p.44-56

HEAT CURING SILICONE RUBBERSNagy J; Roth G

The article reviews the development of silicones from silane

monomers, polysiloxanes, silicone polymers and rubbers

to the chemistry of crosslinking and its economic

importance. Mechanical and electrical properties of a

number of Wacker Elastosil silicone rubbers are compared.

Applications of silicone rubbers are also listed. 14 refs.

Abs. translation from Muanyag es Gumi, No.2, 1999, p.45.

EASTERN EUROPE; HUNGARY

Accession no.771233

Item 79British Plastics and Rubber

April 2000, p.23-4

LIQUID SILICONE OFFERS THE PLASTICMOULDER A PERFORMANCE ELASTOMER

The injection moulding of liquid silicone rubber is

discussed, with particular reference to the use of specially

modified injection moulding machines. The

characteristics and properties of silicone rubbers are

described, and advantages of these properties in

applications in end use industries such as automotive,

electronic, medical, and household appliances. One area

of application driving the growth in their use is the

increase in multi-component moulding with which a

sealing element can be added to a rigid component in one

moulding operation. Machine design modifications are

examined.

WESTERN EUROPE

Accession no.771105

Item 80Biomaterials

21, No.7, 2000, p.649-65

BIOMATERIALS USED IN THE POSTERIORSEGMENT OF THE EYEColthurst M J; Williams R L; Hiscott P S; Grierson I

Liverpool,University

This review focuses on disorders affecting retinal

detachment, and briefly describes the eye anatomy and

the nature and treatment of posterior segment eye

disorders. The roles, required properties and suitability

of materials used in vitreoretinal surgery such as scleral

buckles, tamponade agents or drug delivery devices are

reviewed. Materials used in posterior segment eye surgery

range from non-degradable solid implants to water-soluble

fluids. Silicone oil is currently the most suitable vitreous

tamponade for long-term use but has many disadvantages.

Silicone in solid and non-biodegradable form has been

used for scleral buckles (explants attached to the outside

of the eye by sutures). Water-swellable hydrogel material

can be used for buckling procedures. Vitreous substitute

materials used in eye repair include semifluorinated

alkanes, silicone-fluorosilicone copolymer oil, methylated

collagen, hydroxypropylmethyl cellulose, and crosslinked

polyvinyl alcohol. 132 refs.


WESTERN EUROPE

Accession no.769343


PROCESS FOR SEALING COMPONENTSEXPOSED TO AGGRESSIVE FUNCTIONALFLUIDS AND RTV SILICONE COMPOSITIONSSUITABLE FOR USE THEREINDavis T D



Wacker-Chemie GmbH

RTV-1 silicone sealants resistant to deterioration in the

presence of aggressive functional fluids are prepared from

an organopolysiloxane component comprising a major

amount of silanol-functional organopolysiloxane, a

primary or secondary amine-functional crosslinker, and

both iron oxide and magnesium oxide, optionally together

with auxiliary fillers, adhesion promoters, catalysts, and

customary additives. The gasket materials are particularly

useful in axle and trans-axle seals exposed to fuel

efficiency-promoting aggressive lubricants.

EUROPEAN COMMUNITY; EUROPEAN UNION; USA;


Accession no.769052


METHOD OF MAKING A SILICONE RUBBERWINDSHIELD WIPERReo N J

Specialty Silicone Products Inc.

High performance silicone rubber windshield wiper

blades are provided as a result of moulding a tintable

platinum group metal catalysed silicone compositions

having an intrinsic viscosity of less than 1.3. Improved

lubricity with respect to windshield wiper glass is

achieved by a moulding procedure which effects a transfer

such as a migration, or diffusion of release agent, forexample polytetrafluoroethylene, into the surface of the

silicone rubber windshield wiper blade.

USA

Accession no.768871

Item 83Injection Molding

8, No.4, April 2000, p.42/4

USING TECHNOLOGY TO STAY ON TIME ANDUNDER BUDGETManiscalco M

Boston Medical Products uses a combination of rapid

prototyping, rapid tooling and 3D CAD to bring low-

volume, injection moulded silicone rubber medical

devices to market on time and at a competitive price.

Rapid prototypes of the actual mould insert are produced

on a Sanders system. A toolmaker works with these

prototypes and returns sintered tool inserts within two

weeks.

BOSTON MEDICAL PRODUCTS INC.; CADKEY

INC.; NDM INC.USA

Accession no.768540


SILICONE GEL COMPOSITION AND SILICONEGEL FOR USE IN SEALING AND FILLING OFELECTRICAL AND ELECTRONIC PARTSEnami H; Hamada Y; Nakamura A; Saiki T


The present invention provides a silicone gel composition

for use in sealing and filling of electrical and electronic

parts, which are characterised by the fact that when the

composition is cured, the composition forms a silicone

gel in which the loss elastic modulus at a temperature of

25 deg C, and a shear frequency of 0.1 Hz is 100 to 1000

Pa, and in which the complex elastic modulus is 100000

Pa or less, and a silicone gel which is characterised by

the fact that in a silicone gel which seals or fills electrical

or electronic parts, the loss elastic modulus of this silicone

gel at 25 deg C and a shear frequency of 0.1 Hz is 100 to

10000 Pa, and the complex elastic modulus is 100000 Pa

or less.

JAPAN

Accession no.766438


CONTINUOUS PROCESS FOR PRODUCING ASILICONE POLYMERCurrie J; Griffith P; Herron W; Taylor R

Dow Corning Corp.

This involves the sequential steps of (i) polymerisation

of a linear silanol group containing siloxane by

condensation polymerisation or of a cyclosiloxane by ring

opening polymerisation or of a mixture of the linear and

cyclosiloxanes with a phosphazene base in the presence

of water and the presence or absence of a filler in an

extruder, (ii) neutralising the reaction mixture in an

extruder and (iii) stripping the neutralised reaction mixture

to remove volatile materials. Preferably, step (iii) is

performed in an extruder. More preferably, steps (i), (ii)

and (iii) are all performed in the same extruder.


WESTERN EUROPE; WESTERN EUROPE-GENERAL

Accession no.766190

Item 86New Scientist

165, No.2223, 29th Jan.1999, p.36-9

BORDER OF ORDERBrooks M

The secret of the winter flounder’s survival is a tiny

antifreeze protein: as the disordered water molecules in

its blood begin to turn into the ordered structure of ice,

the protein moves in to break them apart. Just as the

flounder can hold molecular order at bay in its

bloodstream, researchers are learning to map and control

the boundaries between ordered and disordered materials.

Eventually, they hope this will help them devise better



ways to preserve frozen foods or design materials with

remarkable properties to order. But first the researchers

aim to marry the processing power of silicon with the

flexibility of plastics to create cheap, bendy and disposable

electronics. If researchers can make the marriage work,

it could lead to drug packaging that sports unbreakable

polymer display screens, for example. Touch the screen

and health information or medical advice could be at your

fingertips. There would be countless uses for computer

screens that could be worn on a sleeve or rolled up and

stuffed in a pocket - an electronic map for tourists, for

example, or a complete set of wiring diagrams for an

engineer working at a remote location. This plastic-silicon

combination could also be used to make speakers,

microphones or a new generation of sensors to spot

pollutants or diagnose disease. Details are given.

CORNELL UNIVERSITYUSA

Accession no.765153

Item 87Biomaterials

21, No.6, 2000, p.629-36

MICROGROOVED SILICONE SUBCUTANEOUSIMPLANTS IN GUINEA PIGSWalboomers X F; Jansen J A

Nijmegen,University

Cell-substratum interactions are of fundamental

importance for the reaction of body tissues to surgically

implanted foreign materials. The influence of 2 mu m

wide microgrooves, with various depths (0.5-6 mu), on

capsule formation around subcutaneous silicone implants,

is investigated in an animal experiment. Silicone sheets

with microtexture are glued around silicone tubes. These

implants are placed subcutaneously in eight guinea pigs

for ten weeks. The implanted tubes are removed including

all surrounding tissues, and processed for light microscopy

and subsequent histomorphometrical evaluation. All

removed implants are surrounded by a thin fibrous

capsule, and it is observed that this capsule is separated

from the implants by a thin, single layer of mono- and

multinucleated phagocytotic cells. In histomorphometry

no significant differences are seen in relation to the

reaction towards the various textures. It is concluded that

microtextures do not have an effect on the morphological

characteristics of capsule formation around silicone

implants in soft tissue. 32 refs.



Accession no.765055


FOAMABLE SILOXANE COMPOSITIONS ANDSILICONE FOAMS PREPARED THEREFROMLoiselle B P; Rapson L J

Dow Corning Corp.

Foamable organosiloxane compositions are disclosed

which yield, upon cure, silicone foams having low density

and decreased friability, comprising a siloxane base

polymer having an average of at least two hydroxyl groups

per molecule, a silicon-containing crosslinker for the

siloxane base polymer, wherein the crosslinker contains

at least two -SiH groups per molecule; a platinum group

catalyst; a silicone resin copolymer; and, optionally, a

blowing agent; and silicone foams prepared therefrom. A

method of weather-stripping a door or window using a

silicone foam so prepared is also disclosed.

USA

Accession no.764891


90, No.2, Feb.2000, p.32-3

SILICONE COMPOSITESPohmer K

The development of innovative self-adhesive liquid

silicones has made it possible, for the first time, to produce

rigid/flexible composites in thermoplastics and silicones

using hardened steel moulds without any coating.


WESTERN EUROPE

Accession no.764600

Item 90Pitture e Vernici

76, No.2, 1st-15th Feb.2000, p.31-6

Italian; English

WATER-BASED SILICONE SEALANTS.EVOLUTION OR REVOLUTIONGiraud M Y; Feder M; Dubouis R

Conchem

Various aspects of the water-based silicone sealants

industry are discussed in some detail. Information

presented includes a brief historical review, a brief

comparison of conventional sealants, market research

carried out by Rhone Poulenc, preparation of sealants by

the emulsion polymerisation and by Rhodalis technology

and a comparison of the two methods, and a comparison

with other sealants.

RHONE-POULENC SAEUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE;

WESTERN EUROPE

Accession no.763094

Item 91Medical Device & Diagnostic Industry

Nov.1999, p.38/44

SILICONE RUBBER FOR MEDICAL DEVICEAPPLICATIONS



Heide C

Vesta Inc.

A general overview is presented of silicone rubbers,

including information on physical properties, fabrication

methods and potential advantages for medical device

manufacturing. Their chemical structure and curing

mechanisms are also investigated. 4 refs.

USA

Accession no.760269

Item 92156th ACS Rubber Division Meeting - Fall 1999.


Orlando, Fl., 21st-23rd Sept.1999, paper 93

SILICA-PDMS INTERACTIONS - A NEW VIEWOF AN OLD QUESTIONBarthel H

Wacker-Chemie GmbH

(ACS,Rubber Div.)

Fumed silica is an amorphous synthetic silicon dioxide

used in a variety of technical applications. Besides free

flow of powders and thickening of liquids, the

reinforcement of silicone elastomers is of main

importance. Mechanisms of reinforcement are still an

issue of scientific discussions. However, it has been settled

that interactions between the silica surface and the

polydimethylsiloxane (PDMS)chain segments play amajor role. Recent efforts to understand those interactions,

both on a molecular and an atom scale level, are reviewed.

Hydroxylated and silylated silicas with defined degree

of silylation are investigated. As an experimental

adsorption technique, inverse gas chromatography, in an

infinite dilution and a finite concentration mode, is used.

Adsorption of linear oligomers of dimethylsiloxy units

reveal that steric factors dominate the energy of

adsorption. On an atom-scale level, a series of

computational studies together with experimental

vibration spectroscopy is performed. Semi-empirical

quantum chemical techniques, basing on AM1 and PM3

parameters, are used to study nanoscale surface facets.

Unspecific, dispersion forces together with induced

dipole-dipole interactions control the adsorption of

PDMS- on fumed silica, and discrete H-bonding are of

minor importance. A review on various results of

structures and interaction energies from different methods

is presented. 35 refs.


WESTERN EUROPE

Accession no.759686




REVIEW OF MECHANICAL VERSUS MANUALNICKING OF SILICONE RUBBER

Briggs G; Korthals K

Laur Silicone Rubber Compounding Inc.

(ACS,Rubber Div.)

A mechanical nicking device is initially evaluated to see

if there is justification, through testing, for its purchase.

The goal is to achieve more accuracy and precision in the

Tear Die B tests (ASTM D 624). The original test uses

silicone samples of different durometers and three

operators. In this phase, it is shown that the standard

deviation varies less when done by mechanical means.

Research is continued using side by side comparisons on

various materials with actual production lots. A database

is created tracking Tear Die B standard deviation for the

mechanical versus hand nicking. The performance of each

method is reviewed using silicone materials with a range

of durometers. 4 refs.

USA

Accession no.759667




SILICONE FOAM - CAN IT MEASURE UPSuprenant R; Wolosen M; Larson E; George C

Rhodia Silicones Inc.

(ACS,Rubber Div.)

Silicone foam materials have been available commercially

for many years. The materials have been either heat cured

rubber or RTV (room temperature vulcanised). Emphasis

is placed on RTV preparation of foam, details are given

of the tools needed to develop low density, high strength

properties. The development of analytical tools used in

efforts to produce silicone foam suited to compete with

PU foam are examined. 158 refs.

USA

Accession no.759666




COMPRESSION SET BEHAVIOUR OFADDITION CURABLE SILICONE RUBBERMeguriya N; Yoshida T


(ACS,Rubber Div.)

Injection moulding of liquid silicone rubber is becoming

increasingly important. Compared to conventional

compression moulding, liquid injection moulding systems

(LIMS) can be moulded at a much faster pace and

accuracy, required for less steps, which reduces labour

cost and improves productivity. LIMS material has

superior purity and clarity as well as low odour and neutral

taste because it is cured through addition (hydrosilylation)



reaction, so that no by-products are produced and the

whole process goes in closed system. They can also be

produced fully automatically (no runners, flashless, auto-

ejection) if the system is designed properly. Silicone

rubber is used in many fields for their various properties

not available in any other organic rubbers. Compression

set of silicone rubber is very low and varies little -50 deg.C

to 200 deg.C, compared to organic rubbers which are not

suitable for use as sealing materials at their extreme

temperature.

JAPAN

Accession no.759663

Item 96Philadelphia, PA, 1998, pp.18. NALOAN.

MIL-I-46852. INSULATION TAPE,ELECTRICAL, SELF ADHERINGUNSUPPORTED SILICONE RUBBERUS Military

MIL-I-46852

Version C Notice 1. Superseded by A-A-59163 on 13/2/

98. Photocopies and loans of this document are not

available from Rapra.

USA

Accession no.759594




NEW TRENDS IN SILICONE ELASTOMERTECHNOLOGYBurkus F S; Amarasekera J

General Electric Silicones

(ACS,Rubber Div.)

The trend to high performance, long lasting industrial

subsystems is driving the need for high-performance

elastomers. A high performance elastomer should maintain

material integrity while being exposed to harsh

environmental conditions including thermal cycling,

solvent and chemical exposure, high pressures and high

stress environments. Silicone elastomers are the materials

of choice for such applications and have inherent benefits

when compared to standard organic elastomers. These

properties are described, and compared and contrasted with

those of other elastomeric systems. New material

developments and processing techniques have resulted in

the use of silicone elastomers in applications previously

unattainable. These new material developments are

discussed, as is the process of liquid injection moulding of

elastomers with an emphasis on product design, the

structures of the siloxanes used, the productivity of the

process and the properties of the resulting elastomer. 6 refs.

USA

Accession no.758361

Item 98Journal of Thermal Analysis and Calorimetry

57, No.1, 1999, p.323-8

DEVELOPMENT OF A NEW SILICONE BASETRANSDERMAL SYSTEM. III. STUDY OFTHERMAL PROPERTIES OF SILICONEELASTOMERS CONTAINING LIQUIDINGREDIENTSWagner O; Kenessey G; Liptay G

Budapest,Technical University; MOL Hungarian Oil &

Gas Co.

Commonly-used base silicone elastomers for transdermal

therapeutic systems, i.e. cured polydimethylsiloxanes,

were studied with particular reference to the change of

the inner polarity of silicone elastomers containing various

amounts of polar liquid ingredients and trifunctional

silicone additives. It was shown that the polarity of the

inside of the matrix was related to the diffusion properties

of model substances and thermal properties of silicone

elastomers. The ingredients used changed the matrix

framework, which was also influenced by the type of

trifunctional additive. These properties were markedly

dependent on the timing of the measurement.

Measurements carried out after 48 hours of the production

of the polymer showed reproducible properties, indicating

that the final structure of the polymer was formed. These

results showed that the ingredients influenced the

properties of the silicone matrices significantly, so that

the characteristics of drug release from pharmaceutical

forms could also be varied. 10 refs.


Accession no.755874


41, No.9, 1997, p.26/32

German

FOAMING OR FOAMABLE SEALS (PART I)?Kayed J

Wil SG (Schweiz)

Foam-in-place seals promise great savings in costs

compared with pre-formed sealing elements. The market

offers different methods and materials, so that the most

varied problem definitions can be solved. First aid to help

decide on the choice of the right system is given in this

article. Part II of this contribution, published in the next

edition (Oct.1997), surveys the properties of starting

materials and completed seals as well as special technical

processes. A list of references appears in the 1997 October

issue. Technical aspects here cover foaming polyurethane

mechanisms and silicones, as well as chemically foaming

seals, physically foamable seals and hot melts for foam-

in-place seals, including temperature and air moisture as

processing parameters.



Accession no.754449




29, No.5, 4th Oct.1999, p.6

SURGICAL METHODS IMPACTINGPROCESSORSBoyd J

Trends in surgical procedures have led to the increased

use of minimally invasive surgical procedures in place of

traditional ‘open body’ methods for operations such as

gall bladder surgery, hysterectomies and appendectomies.

These techniques are creating opportunities for silicone

rubber processors, since silicone rubber offers advantages

over other materials such as PVC, latex and polyurethanes

in terms of biocompatibility and processability. Problems

with latex allergies, and perceived potential hazards with

PVC are leading to their replacement with silicone rubber

medical equipment, including long-term implants such

as pacemakers.

USA

Accession no.753319

Item 101Rubber Chemistry and Technology

72, No.1, March-April 1999, p.152-164

BASIC STUDY OF CONTINUOUS ULTRASONICDEVULCANISATION OF UNFILLED SILICONERUBBERDiao B; Isayev A I; Levin V Y

Akron,University

Prepared samples of a peroxide cured silicone rubber were

devulcanised by passing through an extruder fitted with

an ultrasonic die at different throughput rates and back

pressures. A branched structure in the network of the

devulcanised material, the degree of which depends on

the amplitude of the ultrasonic waves, is indicated.

Assessment of amount of devulcanisation was made with

gel fraction and crosslink density measurements. The

devulcanised samples were then revulcanised with further

peroxide, both alone and blended with fresh silicone

rubber. Mechanical properties of the revulcanised samples

were compared with both the original vulcanised samples

and those prepared from a blend of devulcanised and fresh

material. Indications are that a blend of devulcanised and

fresh material has similar tensile but higher elongation

than virgin material. (Originally presented to ACS

meeting, Cleveland, Oct 21-24, 1997, revised May 98)

17 refs

USA

Accession no.753130

Item 102Plastics Technology

No.10, Oct.1999, p.54/61

LIQUID INJECTION MOLDING HITS ITSSTRIDEOgando J

Growth in the use of liquid injection moulding as a

processing method is examined, as suppliers in North

America report sales growth in liquid silicone rubber in

excess of 10% a year, and producers of liquid injection

moulding machines also report a similar picture of double

digit growth. Trends and developments driving this growth

are discussed, and include the ability to mould bigger parts,

the availability of higher mould cavitation, gas-assist

moulding, the possibility to produce dual-durometer parts

and thermoset/thermoplastic combinations. Developments

in machinery are reviewed with details of specific

machines.

NORTH AMERICA

Accession no.752983

Item 103European Coatings Journal

No.10, 1999, p.26/42

SILICONES FOR WATERBORNE WOODCOATINGSEaston T; Cackovich A

Dow Corning Europe

The aim of this paper is to demonstrate the versatility of

silicone technology in meeting the demands of wood

coatings. The choice of a suitable additive or combination

thereof, are shown to provide improved surface lubricity,

gloss, levelling, blocking and chemical resistance. Details

are given of new chemical structures and delivery forms

of silicone which provide better performance in water

based wood coatings. Physical and chemical modification

techniques are discussed for polydimethyl siloxane. 4 refs.

EUROPE-GENERAL

Accession no.751612

Item 104155th ACS Rubber Division Meeting, Spring 1999.

Conference Preprints.

Chicago, Il., 13th-16th April 1999, Paper 83, pp.16

CLOSED LOOP FUZZY CONTROL OF PARTWEIGHT IN INJECTION MOLDING OF LIQUIDSILICONE RUBBER (LSR) BASED ON PVTBEHAVIORHaberstroh E; Henze E

IKV

(ACS,Rubber Div.)

A closed loop system based on pressure-volume-

temperature behaviour for the control of part weight in

the injection moulding of liquid silicone rubber is

described. Depending on the course of cavity pressure

and mould temperature, a fuzzy logic based algorithm

determines the required changes in dosing volume in the

case of process disturbances and ensures a constant part

weight. 3 refs.


USA; WESTERN EUROPE

Accession no.749893



Item 105155th ACS Rubber Division Meeting, Spring 1999.


Chicago, Il., 13th-16th April 1999, Paper 80, pp.18

MULTI-COMPONENT INJECTION MOLDINGOF RIGID-FLEXIBLE COMBINATIONS MADEFROM THERMOPLASTICS, RUBBER ANDLIQUID SILICONE RUBBERRonnewinkel C; Haberstroh E

IKV

(ACS,Rubber Div.)

Factors influencing adhesion between rubber and

thermoplastic components in parts produced by two-

material injection moulding are examined. Results are

presented of studies undertaken to optimise adhesion in

parts produced by this technique from liquid silicone

rubber and polyamides or PBTP. 22 refs.


USA; WESTERN EUROPE

Accession no.749891


MEDICAL ELECTRICAL LEAD ANDREINFORCED SILICONE ELASTOMERCOMPOSITIONS USEDPaulsen M J; Miller J P; Ebert M J

Medtronic Inc.

A medical electrical lead and a reinforced silicone

elastomer used therein. The silicone elastomer used is

preferably made from a novel silica reinforced

polysiloxane material, which after vulcanisation by cross-

linking exhibits improved mechanical properties. The

medical electrical lead features an electrode at a distal

end thereof and an elongated electrical conductor

extending between the electrode and the connector, the

conductor in electrical contact with the electrode at a distal

end and in electrical contact with the electrode at a distal

end, the conductor comprised of several wires or wire

bundles wound in a multifilar coil configuration.

USA

Accession no.749726


PHOTO-CURABLE LIQUID SILICONE RUBBERCOMPOSITIONS FOR TEMPLATING MOTHERMOLDSFujiki H; Sakamoto T


A photo-curable liquid silicone rubber composition is

curable upon exposure to light into a cured product having

a Shore A hardness of 20-60 and a light transmittance of

at least 10% at a wall gauge of 10 mm. The composition

is suitable for forming a transparent templating mother

mould which allows a photo-curable liquid resin cast

therein to be cured with light transmitted by the mould

wall.

JAPAN

Accession no.749721


EXTRUSION METHOD OF PRODUCING APOLYMERIC SEALING/SPRING STRIPScott M K

Crane Plastics Co.Ltd.

The present invention pertains to a polymeric sealing/

spring strip and method of producing the same. The

polymeric strip has various embodiments which are based

upon the incorporation of silicone rubber. Some of the

embodiments are based on the formation of a resilient

silicone rubber surface to provide a sealing/spring contact

with an opposing surface period. Other embodiments

incorporate the silicone rubber in such ways as to utilise

its resilient properties to produce a sealing/spring strip

which has improved mechanical resilience properties. The

method allows the production of a sealing/spring strip in

accordance with the present invention by using extrusion

techniques.

USA

Accession no.746980

Item 109Polymer Bulletin

42, No.6, July 1999, p.717-24

SOLID PARTICLE EROSION OFELECTRICALLY INSULATING SILICONE ANDEPDM RUBBER COMPOUNDSBesztercey G; Karger-Kocsis J; Szaplonczay P

Furukawa Electric Institute of Technology; Institut fuer

Verbundwerkstoffe GmbH; Kaiserslautern,University;

Furukawa Composite Insulators

A study was made of the particle jet erosion behaviour of

outdoor insulating silicone and EPDM rubber

compositions subjected to sandblasting. The effects of

impact angle and amount of non-reinforcing filler

(alumina trihydrate) and the wettability of the sandblasted,

contaminated silicone rubber surfaces in the incubation

period are discussed. 8 refs.

EASTERN EUROPE; EUROPEAN COMMUNITY; EUROPEAN

UNION; GERMANY; HUNGARY; WESTERN EUROPE

Accession no.745933


COSMETIC CREAM COMPOSITIONCONTAINING SILICONE GEL MATERIALLee W; Bianchini R J; Hilliard P J

Colgate-Palmolive Co.



Disclosed is a solid cosmetic composition (e.g. a cream

composition) containing an active cosmetic material (e.g.

a deodorant active, an antiperspirant active, a sunscreen,

an insect repellent and/or an anti-fungal agent) and a

silicone gel material. The silicone gel material includes

(a) a volatile silicone material and (b) an

organopolysiloxane material as a gelling agent, able to

form a gel after being mixed with the volatile silicone

material. The organopolysiloxane material can be a

reaction product of a vinyl-terminated siloxane polymer

and a hydride crosslinking agent. The composition can

be formed by mixing the active cosmetic material and

silicone gel material at ambient temperature. The

compositions do not need particulate or clay thickeners

or waxy gelling agents.

USA

Accession no.745873


28, No.24, 28th June 1999, p.1/21

STUDY FINDS BREAST IMPLANTS DON’TCAUSE ILLNESSMoore M

Silicone gel breast implants do not cause cancer or

systemic disease in women, according to a government-

funded study. But other complications, such as implant

rupture and deflation or contraction of the fibrous tissue

around the breast, are fairly common and need to be

studied further, concluded the three-member panel

organised under the auspices of the Institute of Medicine,

the medical arm of the National Academy of Sciences.

Dow Corning, inventor of silicone implants, said the

report ‘provides additional solid evidence that breast

implants do not cause disease’. The panelists, who have

no connection with any parties in the silicone implant

dispute and worked without compensation, reviewed more

than 3,000 publications on implants, giving particular

weight to peer-reviewed scientific articles. All the

evidence indicates that rupture, tissue contraction and

other local complications resulting in pain, disfigurement

or infection are the main problems with silicone implants,

according to the study. Details are given.

US,NATIONAL ACADEMY OF SCIENCES;

US,INSTITUTE OF MEDICINE; DOW CORNING

CORP.USA

Accession no.745570


SILICONE RUBBER COMPOSITIONBaba K; Hirai K; Matsushita T


This comprises a polyorganosiloxane gum of given

formula, microparticulate silica and a methyl-substituted

benzoyl peroxide having a maximum grain diameter not

exceeding 50 micrometers and an average grain diameter

of 30 micrometers. When cured, it exhibits reduced non-

uniformity in the physical properties because of fewer

voids, resulting in decreased frequency of spark-outs in

insulated wires.

JAPAN

Accession no.744615


SILICONE RUBBERS WITH IMPROVED MOLDRELEASE PROPERTIESKnies W; Guske W

Wacker-Chemie GmbH

The invention relates to polyorganosiloxane rubber

compositions which vulcanise to elastomers under the

influence of heat and comprise: (A) 100 parts by weight

of organopolysiloxane; (B) 10 to 200 parts by weight of

filler; (C) 0.1 to 10 parts by weight of crosslinking agent

which forms free radicals; and (D) 0.05 to 10 parts by

weight of aliphatic alcohol with C8 to C30 alkyl radicals.

The aliphatic alcohol (D) acts as an internal mould release

agent.


WESTERN EUROPE

Accession no.744249


SILICONE SEALING MATERIAL EXHIBITINGHIGH STRESS RELAXATIONChiotis A; Wojtowicz J

Raychem Corp.

A silicone gel formulation is described having a Voland

hardness of from about 6 to 30 grams, a tack of from

about 17 to 35 grams, and a stress relaxation greater than

50%. The material is especially suitable for sealing the

back end of connectors containing a multiple of fine wires

with gauges between about 14 gauge and 28 gauge. It is

particularly suitable to seal the back end of an automotive

connector subjected to a wide variety of harsh

environmental conditions.

USA

Accession no.741955


LUBRICANT SYSTEM FOR HYPODERMICNEEDLES AND METHOD FOR ITSAPPLICATIONPelkey B J

Becton,Dickinson & Co.

A lubricious coating having a first layer formed from at

least a partially cured organosiloxane copolymer and



PDMS having a viscosity greater than about 1,000

centistokes and a second layer including PDMS having a

viscosity between about 50 and 350 centistokes is applied

to and adherent to the outside surface of the elongate tube

of the hypodermic needle.

USA

Accession no.741175


LIGHT PERMEABLE METAL PLATED RUBBERKEYTsai J

Silitek Corp.

The key is made of silicone rubber and has a hardened

head on top printed with light-permeable ink. The key is

metal plated and replaces rubber keys and keys with

adhered rubber and silicone rubber.

TAIWAN

Accession no.741173


METHOD FOR MOULDING STRUCTURALPARTS UTILISING MODIFIED SILICONERUBBERWeiser E S; Baucom R M; Snoha J J

US,National Aeronautics & Space Administration

This invention improves upon a method for moulding

structural parts from preform material. Preform material

to be used for the part is provided. A silicone rubber

composition containing entrained air voids is prepared.

The silicone rubber and preform material assembly is

situated within a rigid mould cavity used to shape the

preform material to the desired shape. The entire assembly

is heated in a standard heating device so that the thermal

expansion of the silicone rubber exerts the pressure

necessary to force the preform material into contact with

the mould container. The introduction of discrete air voids

into the silicone rubber allows for accurately controlled

pressure application on the preform material at the cure

temperature.

USA

Accession no.740203

Item 118Kunststoffe Synthetics

No.1, 1998, p.12-4

German

NEW USES WAITING FOR DISCOVERYPohmer K; Spirig N

Bayer AG; Lonstroff AG

Silicone rubbers have an average growth rate of 5%. They

can be injection moulded with a special mix and dosing

technology. Easily processable, they can be made into

combinations with thermoplastics into a range of

applications from babies’ dummies and the membranes

in breathing masks, to long-wave stabilizers, gaskets for

irons, percolators, dishwashers and washing machines.

In combined materials the usual processing temperature

is 180-230C but this becomes much less in combinations

using liquid silicone rubber (LSR). LSR has a heat

stability to 200C, cold flexibility to -50C, good

mechanical properties over a long time, chemical

resistance and electrical and thermal isolation. Combined

with thermoplastics, LSR is also used in hair-dryer

diffusers. There are 2,000 LSR parts in the average car. 4

refs.


WESTERN EUROPE

Accession no.739935

Item 119Rubber World

220, No.3, June 1999, p.35-7

COINJECTION MOULDING FOR LIQUIDSILICONE RUBBERTimmerman J

Engel GmbH

Coinjection moulding is an exciting new process for the

moulding of liquid silicone rubber that opens up new

possibilities. Coinjection involves injecting two or more

similar materials into the mould cavity together. One

material forms the skin and the other forms the core. The

process is described, together with equipment

requirements and design considerations.


WESTERN EUROPE

Accession no.739157

Item 120Muanyag es Gumi

36, No.2, Feb.1999, p.45-56

Hungarian

HEAT-CURING SILICONE RUBBERSNagy J; Roth Gy

Budapest,Technical University

The authors review heat-curing solid and liquid silicone

rubbers, with particular regard to the properties,

processing characteristics and wide applicability of this

group of elastomers. 14 refs. Articles from this journal

can be requested for translation by subscribers to the Rapra

produced International Polymer Science and Technology.


Accession no.738759

Item 121Adhesive Technology

16, No.2, June 1999, p.31

UNDER PRESSUREGreene K



Adhesive Research Inc.

Adhesives play multiple roles in the construction of airbag

inflators. Adhesive Research first supplied adhesives to

the airbag industry when Seal Methods encountered a

problem with its acrylic adhesive system which was

releasing combustible gases during inflation. It was

determined that silicones, with their thermal stability, low

outgassing characteristics and capacity for a tight,

hermetic seal, were most promising.

USA

Accession no.735653


Biomaterials)

48, No.3, 1999, p.354-64

SILICONE GEL BREAST IMPLANT FAILUREAND FREQUENCY OF ADDITIONALSURGERIES: ANALYSIS OF 35 STUDIESREPORTING EXAMINATION OF MORE THAN8,000 EXPLANTSMarotta J S; Widenhouse C W; Habal M B; Goldberg E P

Florida,University; Tampa Bay,Craniofacial & Plastic

Surgery Center

Although it is well known that silicone gel breast implants

(SGBIs) produce many local complications and

necessitate frequent surgical revisions, no large cohortretrospective quantitative analysis of clinical data has been

reported to date, especially for the prevalence of failures

and additional surgeries. Data from 35 different studies

that encompass more than 8,000 explanted SGBIs are

analysed and reported. Because examination of a

prosthesis when explanted is the definitive method for

determining shell integrity, the only studies used are ones

that report implant duration, the total number of SGBIs

explanted and the number of SGBIs for which shell

rupture or failure (not intact) is confirmed upon surgical

removal. An exponential regression plot of data indicates

a direct correlation of implant duration with percent shell

failure. SGBI failure is found to be 30% at 5 years, 50%

at 10 years and 70% at 17 years. The failure rate is 6%/

year during the first five years following primary implant

surgery. ANOVA comparison of three implant age groups

(mean implant durations of 3.9, 10.2 and 18.9 years)

indicates a highly significant statistical correlation of

percent failure with implant duration. Complications

necessitating at least one additional surgery occur for 33%

of implants within six years following primary implant

surgery. Shell failure is found to be an order of magnitude

greater than the 4 to 6% rupture prevalence suggested by

the AMA Council on Scientific Affairs in 1993, the 0.2 to

1.1 % cited by manufacturers at that time and the 5%

rupture that was stated to be ‘not a safety standard that

the FDA can accept’. 71 refs.

USA

Accession no.734781

Item 123International Rubber Exhibition and Conference 1999.

Conference proceedings.

Manchester, 7th-10th June 1999, Materials paper 1.

BENEFITS OF SILICONE ELASTOMERS INAUTOMOTIVE APPLICATIONSYouren J

Dow Corning Ltd.

(Crain Communications Ltd.)

Automotive engines have become increasingly complex

and powerful and the engine compartment more crowded.

This has resulted in higher temperatures and more

aggressive environments for rubber components. These

changes have resulted in increasing use of silicone

elastomers for a variety of engine seals covering fuel and

oil applications, ignition components and dynamic seals.

Increasing safety requirements together with

miniaturisation has resulted in silicones being widely used

in airbag production rather than organic rubbers. Many

of the above applications are described, together with the

use of existing and new product and process technologies

to make today’s silicone automotive components.


WESTERN EUROPE

Accession no.734464

Item 124Antec ’99. Volume III. Conference proceedings.

New York City, 2nd-6th May 1999, p.2934-7. 012

SELECTION OF SILICONE SEALANTS FORHEAVY TRUCK AND OFF-ROAD VEHICLEAPPLICATIONSBrennan J E; DiPaola D J

Texas Instruments Inc.

(SPE)

The unique sealing requirements encountered in heavy

truck and off-the-road vehicle applications warrant the

investigation of silicone sealants for this marketplace. The

candidate sealants are subjected to a selection protocol

based on lap shear strength as a function of cure time and

after immersion in water, engine wash fluid and common

automotive fluids. An acid cure silicone does not adhere

well to chromate plated steel, and its adhesion to brass

deteriorates after fluid immersions. A neutral cure silicone

adheres well on any of the substrates, and retains adhesion

after fluid immersions. Neutral cure materials are

recognised as the best choice for future product

performance testing. 3 refs.

USA

Accession no.734271

Item 125Antec ’99. Volume 1. Conference proceedings.

New York City, 2nd-6th May,1999, p.539-44. 012

COMBINING LIQUID-SILICONE-RUBBERSWITH THERMOPLASTICS TO RIGID-



FLEXIBLE COMBINATIONS USING 2-COMPONENT INJECTION MOULDINGRonnewinkel C; Haberstroh E

Institute for Plastics Processing

(SPE)

The production of components consisting of flexible

silicone rubber bonded to rigid thermoplastics using two-

component injection moulding techniques is discussed.

The strength of the bond at the interface between a

polyamide and silicone rubber was investigated using an

injection moulded tensile test bar. It was concluded that

such components could replace rubber-metal

combinations for certain applications. 15 refs.


WESTERN EUROPE

Accession no.732951

Item 126Adhesives & Sealants Industry

6, No.3, April 1999, p.38-9

PSAS INCREASE SAFETY ANDEFFECTIVENESS OF AIRBAG INFLATORS

Adhesives Research and Seal Methods have jointly

developed a new generation of pressure sensitive adhesive-

component solutions for automotive airbag inflator

applications. In general, adhesives for airbag inflators serve

to position and set the airbag in place, hermetically seal the

propellant and attach the propellant cover. It was determinedthat silicones, with their thermal stability, low outgassing

and capacity for a tight hermetic seal, were most promising.

ADHESIVES RESEARCH INC.; SEAL METHODS

INC.USA

Accession no.731126

Item 127Kauchuk i Rezina (USSR)

No.6, 1998, p.10-6

Russian

ELECTRICAL CONDUCTIVITY OF FLEXIBLEMATERIALSZuev Yu S

A review is presented of recent studies on the effect of

various factors on the electrical conductivity and volume

resistivity of polymeric systems, also covering the effect

of plasticisers and fillers on the volume resistivity, and

the anomalously low resistivity of black-filled fluorine-

containing rubbers and silicone rubber. Flexible materials

(vulcanisates, thermoplastic elastomers, sealants and

others) are classified in terms of their resistivity. 72 refs.

Articles from this journal can be requested for translation

by subscribers to the Rapra produced International

Polymer Science and Technology.

RUSSIA

Accession no.726960


45, No.3, 5th Jun.1999, p.240-50

SHEEP, PIG, AND HUMAN PLATELET-MATERIAL INTERACTIONS WITH MODELCARDIOVASCULAR BIOMATERIALSGoodman S L

Connecticut,University

The haemocompatibility of pyrolytic carbon mechanical

heart valve leaflets, PE, and silicone rubber was examined.

Data are given for ovine, porcine and human platelets.

49 refs.

USA

Accession no.726766

Item 129China Synthetic Rubber Industry

22, No.2, Mar.1999, p.70-3

Chinese

ADVANCES IN ADDITION SILICONE RUBBERTan Bi’en; Pan Huiming; Wang Weixing; Zhang

Lianzheng; Zhao Feiming

South China,University of Technology;

Beijing,Aerospace Institute of Materials & Processing

Technology

Advantages in research of addition silicone rubber in high

strength, high heat resistance and addition injectionmoulding were reviewed. 18 refs.

CHINA

Accession no.726408

Item 130Kauchuk i Rezina (USSR)

No.5, 1998, p.33-6

Russian

METHOD OF CALCULATING THE FREE PLAYOF A SEAL OPERATING OVER A WIDETEMPERATURE RANGEShindler V M; Khalo T P

A method is described for calculating the required

tightness of fit of seals based on siloxane rubbers operating

in widely varying temperature conditions. 6 refs. Articles

from this journal can be requested for translation by

subscribers to the Rapra produced International Polymer

Science and Technology.

RUSSIA

Accession no.723338


No.769, June/July 1998, p.66/73

French

HIGH TEMPERATURE VULCANISINGELASTOMERS IN THE BIOMEDICAL SECTOR



Leuci C

Rhodia Silicones

The structure, properties and biomedical applications of

high temperature vulcanising silicone rubbers are

examined. The conformity of Rhodia Silicones’ Silbione

silicone rubbers with European and US regulations

covering such applications is discussed, and results are

presented of studies of the behaviour of these elastomers

when subjected to different sterilisation techniques. 6 refs.

EU; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE;

USA; WESTERN EUROPE; WESTERN EUROPE-GENERAL

Accession no.721744


89, No.1, Jan.1999, p.20-3; p.68/72

RELIABLE PROCESSING OF LIQUIDSILICONE RUBBER (LSR) INTO TECHNICALMOULDINGSHaberstroh E; Henze E; Ronnewinkel C

In a number of research projects, the IKV is working

intensively with raw material and machine manufacturers

as well as the processing industry on technologies for

processing LSR. These activities are concentrating on process

analysis and process development for injection moulding.

Aspects covered include control of the quality of the

moulding, process sequences in the pvT diagram, fuzzy logic

for control of moulding weight, function of the fuzzycontroller, effect of the control system, simulation of the

flow and curing behaviour, multi-component injection

moulding of LSR thermoplastic combinations, polyamide/

LSR composites and production of LSR components with

functional cavities using the gas injection technique. 9 refs.


WESTERN EUROPE

Accession no.719224

Item 133Biomaterials

20, No.3, Feb. 1999, p.291-9

EVALUATION OF THE IN VITROBIOCOMPATIBILITY OF VARIOUSELASTOMERSChauvel-Lebret D J; Pellen-Mussi P; Auroy P;

Bonnaure-Mallet M

Rennes,Universite

An evaluation is presented of the in vitro biocompatibility

of silicone-based rubbers. The dimethylthiazol

diphenyltetrazolium bromide colorimetric test was used

to assess cell viability and flow cytometry was used to

evaluate cell proliferation. Changes in cell morphology

were examined using SEM. Comparisons were made with

PU and PS toxicity controls. 28 refs.


WESTERN EUROPE

Accession no.714416

Item 134ACS Polymeric Materials Science and Engineering.

Fall Meeting 1998. Volume 79. Conference

proceedings.

Boston, Mas., 23rd-27th Aug.1998, p.522. 012

ELASTOMERS FOR IMPLANTABLEAPPLICATIONS - SILICONE ORPOLYURETHANE ?Skalsky M

Elastomedic Pty.Ltd.

Medical device developers have had a very limited choice

of implant materials for highly demanding applications

such as insulation for pacing leads, long term in-dwelling

catheters, synthetic polymer heart valves and coronary

vascular grafts. All of these applications require polymers

with excellent biostability, good mechanical strength and

high resistance to fatigue, abrasion and tear. Traditionally,

silicone rubber was the first material of choice, because

of its excellent biostability, despite shortcomings in the

other material properties. PU, a generic name for a very

large family of synthetic polymers, has emerged as the

principal alternative to silicone rubber because of superior

mechanical properties. 7 refs.

AUSTRALIA

Accession no.713300

Item 135ACS Polymeric Materials Science and Engineering.

Fall Meeting 1998. Volume 79. Conference

proceedings.

Boston, Mas., 23rd-27th Aug.1998, p.514. 012

CHEMISTRY OF SILICONE BASEDBIOMATERIALS AND WHY THEY CONTINUETO BE MATERIALS OF CHOICE FORHEALTHCARE APPLICATIONSPetraitis D J

NuSil Technology

Since their early inception, materials based on silicone

polymers have been characterised by their chemical

inertness. Early silicone materials included greases which

were formulated for insulating electrical ignition systems

used by the military during World War II. Although their

resistance characteristics were primarily concerned with

weathering and other environmental factors such as ozone

and high temperatures, this unique inertness of silicone

polymer based materials ultimately evolved into

biomedical applications. Silicone based materials were

found to be extraordinarily inert to the chemicals present

in biosystems. Silicones are among the most

biocompatible materials known to man and today continue

to outperform other materials in biomedical applications

including applications in such diverse products as

pacemaker leads, intraocular lenses, long and short term

catheter and shunt implants, finger joint implants, as well

as greases, lubricants, encapsulants and adhesives used

in the fabrication, assembly or actual performance of an

endless and continuing to be developed group of



healthcare applications. The basic chemistry involved in

the synthesis of silicone polymers and subsequent product

formulations into elastomers, pressure-sensitive

adhesives, marking inks, fluids and lubricants are

discussed.

USA

Accession no.713295

Item 136Gummi Fasern Kunststoffe

50, No.12, Dec. 1997, p.967-73

German

APPLICATION OF FOAM-IN-PLACE GASKETSKayed J

Instead of prefabricated shaped gaskets physically

manufactured by stamping, injection moulding, extrusion

etc., chemico-technical systems can be employed for the

inline manufacture of precision gaskets (Foam-in-Place

with partial or complete automation). This technique uses

one-, two- or multi-component materials with the help of

mixing and/or metering machines in the low-pressure range.

The fluid compound applied produces a foam gasket with

modifiable physical and chemical properties. At the same

time the adhesion can be adjusted as required, from very

high to zero or near zero. Data are given on the foaming

mechanisms of polyurethanes, silicones and hotmelts for

foam-in-place gaskets. 8 refs. Articles from this journal




WESTERN EUROPE

Accession no.713240

Item 137Rubber Technology International

1998, p.22-5

SILICONE RUBBER FOR ELECTRICALINSULATORSGoudie J

Dow Corning Corp.

The market for composite insulators is growing steadily.

Composite designs generally employ a fibreglass rod or

hollow core for mechanical strength, with an outer housing

made from either silicone rubber, EPDM or EPR. Insulator

service life can be affected by electrical, mechanical and

environmental stresses. One of the biggest problems in

outdoor applications is airborne contamination that settles

on the insulator surface. The surface of a silicone elastomer

has a unique ability to interact with the contaminant and

control leakage currents. 6 refs.

USA

Accession no.713200

Item 138IRC ’98. Conference Proceedings.

Paris, 12th-14th May 1998, p.321-6. 012

French

APPLICATIONS OF SILICONES IN ARTPujol J M

Rhodia Silicones

(AFICEP; Societe de Chimie Industrielle)

Applications of silicone rubbers in moulds for the

reproduction of works of art and in the assembly of glass

objects and repair of stained glass windows are

described. The use of silicone resins in the protection

and restoration of ancient buildings and monuments is

also examined. 1 ref.


WESTERN EUROPE

Accession no.710626


50, No.5, May 1997, p.376-85

German

ROLLS AND ROLLERSZeppernick F

A historical survey is given of the development and use

of polyurethane rubber in rollers and roller coatings, and

of coating of rolls with silicone rubber. Articles from this

journal can be requested for translation by subscribers to

the Rapra produced International Polymer Science and

Technology.


WESTERN EUROPE

Accession no.710477

Item 140Polimery Tworzywa Wielkoczasteczkowe

42, No.5, 1997, p.288-93

Polish

C0NTRIBUTION OF RESEARCH ANDEXPERIMENTAL PRODUCTION AT ICRI TOTHE DISSEMINATION OF SILICONEAPPLICATIONS IN POLANDRosciszewski P; Maciejewski J; Zielecka M; Miazga A;

Paczka J; Porcja I

Warsaw,Industrial Chemistry Research Institute

A historical account is given of the research and development

work carried out on the principal types of silicones that have

been successfully commercialised at the Industrial Chemistry

Research Institute’s Silicone Pilot Plant and at the Organika-

Sarzyna Chemical Works. This includes work on fluids,

emulsions, compounds, resins, varnishes, release agents,

water-repellents for textiles and masonry, adhesives,

antifoaming agents, and room-temperature vulcanising

rubbers. 46 refs. Articles from this journal can be requested

for translation by subscribers to the Rapra produced

International Polymer Science and Technology.

EASTERN EUROPE; POLAND

Accession no.710463




70, No.23, 1st Dec.1998, p.4974-84

RAPID PROTOTYPING OF MICROFLUIDICSYSTEMS INPOLYDIMETHYLSILOXANE(PDMS)Duffy D C; McDonald J C; Schueller O J A; Whitesides G M

Harvard University

A procedure was developed for designing and fabricating

(including sealing) microfluidic systems in an elastomeric

material (PDMS) in less than 24 h. A network of microfluidic

channels was designed in a CAD program. This design was

converted into a transparency by a high-resolution printer

and this transparency was used as a mask in photolithography

to create a master in positive relief photoresist. PDMS cast

against the master yielded a polymeric replica containing a

network of channels. The surface of this replica and that of a

flat slab of PDMS were oxidised in an oxygen plasma and

these oxidised surfaces were shown to seal tightly and

irreversibly when brought into conformal contact. 88 refs.

USA

Accession no.709681


SILICONE PSEUDOGELTiffany J S

A silicone gel-like material having reduced content of

extractable silicone fluid and having rheological properties

approximating human tissue. The gel-like material or

“pseudogel” is useful for filling an implantable prosthesis.

Prior art silicone gel-filled prosthetic implants contain a

high proportion of extractable free silicone fluid. The free

silicone fluid within an implant may enter the host’s body

by diffusion through the prosthetic shell or by rupture of

the outer envelope of the prosthesis. The present filler

material, or pseudogel, is produced by controlling the

crosslinking of the silicone polymer network such that every

polymer chain contains only terminal reactive vinyl groups

but not all of the reactive groups participate in the

crosslinking reaction. In a preferred embodiment, the

polymeric vinyl-terminated starting fluids are selected so

that the average molecular weights of the polysiloxane

polymers comprising the fluid may fall into two or three

distinct ranges. The crosslinker, which is composed of a

siloxane molecule containing silicone hydride groups, is

selected to have relatively high Si-H content. By controlling

the crosslinker concentration, essentially all the chains can

be made to react, but in such a way that chains are only

reacted at one end and functional as non-extractable diluents

between the crosslinked longer chains. The resulting

pseudogel exhibits low extractability and is suitable for

filling a soft-tissue prosthesis such as a breast prosthesis

having a flexible outer shell which contains the pseudogel.

USA

Accession no.707845


42, No.4, 15th Dec.1998, p.485-90

CYTOTOXICITY TESTING OF MATERIALSWITH LIMITED IN VIVO EXPOSURE ISAFFECTED BY THE DURATION OF CELL-MATERIAL CONTACTCiapetti G; Granchi D; Stea S; Savarino L; Verri E;

Gori A; Savioli F; Montanaro L

Bologna,Istituti Ortopedici Rizzoli

Extracts of six addition-type and six condensation-type

silicone dental impression materials were tested with L929

cells according to ISO 10993-Part 5 standard. The

cytotoxicity was evaluated by three different methods.

Contact between cells and material extracts was

maintained for 24 h in the first series of experiments but,

as in vivo application of these materials is restricted to a

few minutes, additional experiments were performed after

1 h of cell/extract contact. The addition-type silicones

were found to be non-toxic even when tested after

prolonged exposure of the cells to the materials while the

condensation-type polymers were cytotoxic at 24 h of

incubation. Most of the silicones were not toxic after 1 h.

16 refs.


WESTERN EUROPE

Accession no.706452

Item 144Nippon Gomu Kyokaishi

69, No.1, 1996, p.23-33

Japanese

AIR BAGS -FOR COMFORTABLE DRIVING INSAFETYSakurai T; Ozaki T; Ushio M

Toyo Gomu Kogyo KK

A discussion is presented of counter-measures taken to

prevent accidents under modern traffic conditions, and

of the development of air-bag systems and materials used

in them such as silicone rubber. 10 refs. Articles from

this journal can be requested for translation by subscribers

to the Rapra produced International Polymer Science and

Technology.

JAPAN

Accession no.705847


68, No.9, 1995, p.667-72

Japanese

SILICONE RUBBERSTakahashi M

Shin-etsu Chemical Industries Ltd.

Mechanical properties, abrasion characteristics,

application areas and patented methods for improving the



friction and abrasion characteristics of silicone rubbers

are discussed. 31 refs. Articles from this journal can be

requested for translation by subscribers to the Rapra


JAPAN

Accession no.705426


68, No.7, 1995, p.453-59

Japanese

PROBLEMS OF ELASTOMERS USED INMEDICINEIkada Y

Kyoto,University

A classification of materials used in medical applications

is given according to their physical capacities, and current

problems relating to the use of polymer materials in

medicine are discussed, with particular reference to

silicone rubber, polyurethanes, natural rubber and

plasticised PVC. 10 refs. Articles from this journal can

be requested for translation by subscribers to the Rapra


JAPAN

Accession no.704946


METHOD OF MAKING A MALE CATHETERWelch D P; Ryan T D; Knutson E M

Mentor Corp.

The catheter has a condom-like sheath of silicone rubber

sealingly engaging the penis of the patient. A catheter

stem at the distal end of the sheath couples to a urine

collection system. The sheath is sealed to the penis by an

adhesive, which is applied to the outer surface of the

sheath at the time of manufacture. A surface preparation

layer is applied over the adhesive. The sheath is rolled up

from the proximal end and unrolled to apply it to the

patient. During the unrolling process, the adhesive layer

is removed from the outer surface and deposited on the

inner surface of the sheath.

USA

Accession no.704566


48, No.4, 1995, p. 249-251

German

FLUOROSILICONE RUBBER - A VERYMODERN MATERIALKlages D; Raupbach U

Rado Gummi GmbH; GE Silicones

A brief historical survey is presented of the use of silicon

compounds, and some statistics are given on worldwide

silicone rubber production. The author discusses

processing of fluorosilicone rubbers and their properties,

including resistance to fuels, oils and solvents, heat

stability and good electrical properties. Articles from this



Technology.


WESTERN EUROPE

Accession no.703558


48, No.4, April 1995, p.244-248

German

HOSES AND COUPLINGSHeitz E

Basic properties are given of materials used in the

manufacture of hoses and hose couplings - inner layers,

reinforcements and covers. The materials covered are

butyl rubber, chlorosulphonated polyethylene, ethylene-

propylene rubbers, natural rubber, acrylonitrile-butadiene

rubber, polychloroprene, polyether-urethane rubber and

silicone rubber. Articles from this journal can be requested

for translation by subscribers to the Rapra produced



WESTERN EUROPE

Accession no.703557

Item 150Industria della Gomma

41, No.8, Oct.1997, p.37-8

Italian

AUTOMATIC PRODUCTION UNIT FORRUBBER-METAL ARTICLESCoscia M

Rutil Srl

The production of an automotive gasket using machinery

developed by Rutil is described. The assembly consists

of a glass fibre-reinforced polyamide base over which is

moulded a silicone rubber gasket, and also incorporates

a number of metal reinforcement washers. The production

unit comprises a pair of C-frame injection presses, one

for moulding the base and the other for overmoulding

the gasket, with rotating tables for handling the parts, a

station for loading the metal washers into the mould, and

an industrial robot for checking the quality of the gaskets

before unloading.


WESTERN EUROPE

Accession no.702481




EXTRUDED SILICONE GEL PROFILESWojtowicz J

Raychem Corp.

A method is provided for making simple or complex

extruded gel profiles and the created article. In a

particularly preferred embodiment, the method involves

the extrusion of a silicone gel composition through a die

into a heated fluid to complete the cure of the gel as well

as to produce the desired gel profile shape. Shapes such

as stars, trapezoids, cusped squares, cusped triangle,

triangles and the like can be fabricated.

USA

Accession no.702431


25, No.4, 1998, p.T/81-4

MAMMARY PROSTHESES WITH APOLYURETHANE SHELLOsorgina I V; Begishev V P; Kondyurin A V; Plaksin S

A

Perm,State University; Russian Academy of Sciences;

Perm,Medical Academy

The shell was manufactured from segmented PU based

on an oligoether in the form of a copolymer of

polyoxypropylene glycol and polytetrahydrofuran and

2,4-toluene diisocyanate. Curing was carried out with 3,3-dichloro-4,4-diaminodiphenylmethane (Diamet Kh). The

shell was filled with a low molecular weight silicone

rubber of the SKTN-Med type. 10 refs. Translation of

Plast.Massy, No.8, 1997, p.26

RUSSIA

Accession no.702190

Item 153International Composites Expo ’98. Conference

proceedings.

Nashville,Tn., 19th-21st Jan.1998, Session 17-D. 627

ENHANCEMENTS IN RUBBER TOOLING/COMPOSITE FABRICATIONThomas J E

Tecnico Corp.

(SPI,Composites Institute)

A rubber tooling/composite fabrication process, where

silicone rubber is utilised as part of the tool assembly, is

described. The entire assembly of metal tool, rubber tool

and composite material is contained by an outer mould.

When heated, the rubber exerts pressure great enough to

laminate composite parts. An autoclave or vacuum system

is not required. Equations govern the sizing and expansion

of the rubber and lead to theoretical pressures, which can

be regulated. Tecnico has refined this process by utilising

heat strips which are placed in critical locations in the

mould. Conductive heating (vs. convection) allows faster

cure cycles than conventional methods. By the addition

or removal of heat strips, cold and hot spots in the mould

are eliminated, which is crucial for control of the rubber

pressure. The heating system also permits the composite

to be cured in virtually any location, as long as there is

electrical power. The process can be further improved by

better heating methods and improved silicone rubbers that

have higher operating temperatures, and could be recycled

into the next rubber casting. Other improvements could

be in the use of cooling systems allowing the mould

assembly to return to ambient temperature in a minimal

amount of time. 3 refs.

USA

Accession no.702051



Nashville, Tn., 29th Sept.-2nd Oct.1998, paper 12. 012

FASTER CURING LOW COMPRESSION SET NOPOST CURE LIQUID SILICONE RUBBERJohnson E


(ACS,Rubber Div.)

The economies of the latest developments in liquid

silicone rubber (LSR) materials and process technology

make feasible the replacement of not only conventional

heat cured silicone rubber, but also organic rubber in many

applications. It is now possible to produce parts of at least

5 g in tools with over 30 cavities, with a production cycle

of as little as 20 seconds. The latest cold runner tool and

moulding press technology make it possible to produce

parts with no waste and no flash. This same technology

also makes possible continuous, fully automated

production. Parts can be ejected from the mould into a

box, ready for shipment with no need for deflashing. The

combination of these factors is, in many cases, rapidly

making older methods of moulded rubber part production

uneconomical, despite the premium cost of the LSR

material. Wacker has developed a unique and very

effective method of preventing after cure that has been

applied to a wide range of LSR products. The new

generation of LSR will enable the production of parts that

can behave like parts made from peroxide cure silicone

rubber, but will be able to cure much faster. They are

moulded in this fast, efficient operation without the need

of any subsequent processing.

USA

Accession no.701851

Item 155Journal of Macromolecular Science C

38, No.4, 1998, p.637-50

REVIEW OF ELECTROSYNTHESIS OFPOLYSILANESubramanian K

Vikram Sarabhai Space Centre



A review of the literature on the electrosynthesis of

polysilane is presented. The general procedure and

monomer systems for electroreductive polymerisation are

described, the mechanism of polysilane formation is

considered and the reductive polymerisation of halosilanes

in the presence of vinyl monomers is discussed. The review

clearly demonstrates that, by a suitable choice of solvent,

supporting electrolyte, dihalosilanes and complexing agent,

the electroreductive formation of Si-Si and C-Si linkages

can be used to synthesise ceramic-grade polysilane and

polycarbosilanes, respectively, with less than 0.1 wt %

oxygen and 20-75% yield of polymer. 45 refs.

INDIA

Accession no.700969


28, No.3, 7th Sept.1998, p.6

LATEX-FREE CATHETER UNVEILED BYROCHESTERMcNulty M

Rochester Medical has launched a latex-free silicone

infection control catheter it believes will have a major impact

on both the acute care industry and the company’s bottom

line. The firm, which soon hopes to ready another innovative

product for the market, has also named a new marketing

and sales director. The maker of latex-free disposable urinary

continence care products introduced Release-NF in May and

June. The product has been in the testing and development

stages for several years. Introduction of the product ‘is the

most extensive marketing initiative the company has

undertaken to date’. It is a silicone-advanced Foley catheter

that delivers a controlled release of the antibacterial agent

nitrofurazone, which is contained in the silicone matrix inside

and outside the catheter. It is aimed at the acute care market

and is the first and only latex-free Foley that works as a drug

delivery system. Details are given.

ROCHESTER MEDICAL CO.USA

Accession no.699940

Item 157Kunststoffe Synthetics

No.9, 1994, p.8-11

German

WHERE HIGH TEMPERATURES AREINVOLVED, RELIANCE IS PLACED ONSILICONESFink P

Wacker Chemie GmbH

The use of liquid silicone rubber for injection moulding

is described as an alternative to the solid material or

other materials.


WESTERN EUROPE

Accession no.699741

Item 158Machine Design

70, No.17, 24th Sept.1998, p.166/8

SILICONE-RUBBER HEATERS STRETCHPRODUCT UTILITYCobb P

Watlow Electric Mfg.Co.,Flexible Products Div.

Novel applications for silicone rubber heaters are reported,

and the versatility of the products are illustrated. Silicone

rubber heaters can be shaped to fit most new products,

and although many existing products can be modified,

the best fit is achieved from working with heater

specialists at the start of new design programs, it is

suggested. The construction of a heater is described,

together with and applications in heating frozen blood

for transfusions, in marine applications, and heating a

silicon wafer on a hot chuck for vacuum vapour

deposition.

USA

Accession no.699576

Item 159Plast’ 21

No.63, Sept.1997, p.34

Spanish

EXTENDED USE OF SILICONES IN THE CAR

A review is presented of automotive applications ofBayer’s Silopren range of liquid and solid silicone rubbers.

BAYER AGEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.698945


218, No.6, Sept.1998, p.20/69

PROCESSING GUIDE TO SILICONE RUBBEREXTRUSIONSTaylor T C

Specialty Silicone Products Inc.

This article is the second part of a series providing a

processing guide to silicone rubber extrusions. Screen

packs and breaker plate, feeding, screw designs, screw

flight design, and dies and guiders are discussed. A

troubleshooting chart is presented.

USA

Accession no.698783

Item 161Journal of Coated Fabrics

27, April 1998, p.326-37

NEW GENERATION OF SILICONEELASTOMERS FOR AIRBAG COATINGSBohin F; Pouchelon A; Surprenant R

Rhone-Poulenc Silicones



In 1996, a new generation of silicone elastomers for

coating was launched on the European market.

Specifically designed to meet the airbag market, these

new products have specific rheological properties

allowing very thin coatings without any change in the

technology or use of a solvent, giving significant cost

reduction for the customer. Giving improved thermal

protection to the fabric, they are very well adapted to the

new generation of airbag inflators arising from the market.

Their specific properties also provide a 100% increase of

the fabric tear strength. 6 refs.


WESTERN EUROPE

Accession no.697986


HEAT SHRINKABLE SILICONE TUBE ANDMETHOD FOR MAKINGTakei H; Shimamoto N; Ohtsuka Y


This tube is made from a silicone rubber composition

comprising a diorganopolysiloxane, a thermoplastic resin,

finely divided silica, an inorganic filler of titanium white,

alumina, quartz powder or talc having a mean particle

size of 0.5 to 15 micrometers and a curing agent by

extrusion moulding, preferably at a drawdown of 150 to

250%, vulcanisation and heat stretching in a radial

direction. It exhibits axial orientation during stretching

and shrinking subsequent thereto and is thus tearable.

JAPAN

Accession no.697587

Item 163RubberTech China ’98. Conference proceedings..

Shanghai, China, 24th-26th March, 1998, paper 17. 012

PROPERTIES AND APPLICATION OFSILICONE RUBBERS (HCR AND LR)Beisswenger H

Wacker Chemie GmbH

(Rapra Technology Ltd.; Crain Communications Ltd.)

The properties, applications, curing and processing of

silicone rubbers are discussed, with particular reference

to the differences between HCR (millable type) and LR

(liquid rubber). The comparisons between the two types

of rubber illustrate advantages and limitations for using

liquid silicone rubbers. Applications in automotive,

personal care products, keypads, baby teats and catheters

are described.

CHINA; EUROPEAN COMMUNITY; EUROPEAN UNION;

GERMANY; WESTERN EUROPE

Accession no.696400


METHOD FOR MICROMOULDING CERAMICSTRUCTURESGhosh S K; Furlani E P; Grande W J

Eastman Kodak Co.

Ceramic articles and structures having spatial features as

small as 0.1 micrometer and having a depth ranging from

2.0 to 100 micrometer are micromoulded using a master

mould of the article or structure to be moulded and

fabricated utilising a silicon wafer and dry etching

technology. A negative master mould is then produced

by placing the silicon master mould device in a

surrounding mould form and filling the mould form with

a silicone or silicone rubber, preferably a RTV silicone

rubber. Such material replicates each of the micro features

of the master mould in great detail to a resolution of the

order of 0.1 micrometer. The negative master mould is

then used in a die to mould the desired individual elements

or structures from a ceramic powder, which is capable of

replicating each of the micro features of the negative

master mould to the desired resolution.

USA

Accession no.695131


ORGANOPOLYSILOXANE COMPOSITIONSWHICH CROSSLINK TO GIVE ELECTRICALLYCONDUCTIVE ELASTOMERSPradl F; Fink P; Noemmer K; Birneder R

Wacker-Chemie GmbH

The invention relates to organopolysiloxane compositions

that when crosslinked form electroconductive elastomers.

The elastomers are formed via an addition crosslinking

method and contain 11-30 wt % with respect to the total

composition of carbon fibres having 0.1-10 mm average

length. The compositions are suitable for producing

injection moulded articles.


WESTERN EUROPE

Accession no.690309


27, No.23, 15th June 1998, p.28

DOW CORNING FORMULAS AID TWO HOSEMAKERSWilson E

Two companies are finding Dow Corning STI’s new

advances in silicone technology key ammunition in their

fight against coolant hose wear and tear. Flexfab Horizons

International and Thermopol are finding success in

utilising Dow Corning custom silicone formulations that

markedly sustain elastomeric hose endurance under

repeated exposure to rigorous pressure and temperatures.

Using the formulations, Flexfab has reported an increase



of 50% in the life of its heater and radiator hoses for Class

8 trucks. The firm now offers a warranty on its hoses for

up to 1.5 million miles. As under-the-hood temperatures

rise, cooling system hoses expand, increasing pressure

exerted upon them by metal stems to which they are

clamped. After cool-down, hose stems thin, caused by

this pressure, resulting in a gradual loss of sealant integrity

over extended periods of use. This loss is known as cold

leak. While the compression set of EPDM has been

measured by Society of Automotive Engineers coolant

hose specifications at 75-85%, and that of generic silicone

at 40%, the elastomeric bulk loss of Dow’s custom

formulated compound is 25%. Details are given.

DOW CORNING STI; FLEXFAB HORIZONS

INTERNATIONAL; THERMOPOL INC.USA

Accession no.689777

Item 167Journal of Biomaterials Applications

13, No.1, July 1998, p.66-73

PROPERTIES OF MAXILLOFACIAL SILICONEELASTOMERS REINFORCED WITH SILICAPOWDERAndreopoulos A G; Evangelatou M; Tarantili P A

Athens,National Technical University

Compounds of a silicone elastomer reinforced with

various amounts of silica powder, which were suitable

for preparing maxillofacial prostheses, were studied for

their mechanical response and wetting properties in terms

of contact angle. TS and EB showed an increase with

increasing silica volume fraction up to 35%, whereas the

Young’s modulus displayed a slight dependence on the

silica content and the resistance to tear increased

continuously with filler volume fraction (Vf). The wetting

properties, assessed via the contact angle, seemed to

degrade with increasing Vf, but a dependence on the

elastomer network density was also recorded. 10 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; GREECE;

WESTERN EUROPE

Accession no.688759


Vol.27, Jan.1998, p.219-36

PRECISION PLACEMENT OF THINPOLYMERIC SILICONE FILMS WITHINFABRICSMeirowitz R

Nextec Applications Inc.

Nextec patented technology is described which allows

for the precision placement of thin polymeric films around

fibres, crossover points and filling in or leaving open

interstitial spaces within fabrics. The choice of polymer,

substrate and placement of polymer is shown to allow

for improvement of properties, such as breathable barrier

performance, controlled porosity, resistance to fluids and

adhesion/release behaviour. Applications of the

technology in apparel, automotive, aerospace and medical

fields are described. The benefits in these applications

are delivered in a process that has no volatile organic

compounds and yields inert residual materials. Examples

of materials and comparative performances are discussed.

7 refs.

USA

Accession no.688755

Item 169Kautchuk und Gummi Kunststoffe

51, No.6, June 1998, p.410/5

German

LIQUID SILICONE RUBBER - PROPERTIESAND APPLICATIONSJerschow P

Liquid silicone rubber is used to produce elastic parts by

injection moulding. Its main properties range from high

resistance against temperatures (both high and low

temperatures) and chemicals to high transparency and

good mechanical properties. It is used in automotive parts,

electronics, medical devices, food and household

appliances and many other sectors. Liquid silicone rubber

is processed fully automatically in an injection moulding

machine. The applications, processing and properties of

liquid rubber are summarised. 5 refs.


WESTERN EUROPE

Accession no.687926


MONITOR PUTTY WITH INCREASINGSTIFFNESSGibbon R M

JMK International Inc.

An exercise putty kit providing manipulative physical

therapy of increasing difficulty comprises a container

of a large mass of borosiloxane putty and a package of

borosiloxane or siloxane putty. At least one small mass

is provided to the patient along with the large mass, the

small mass and large mass being manipulated by the

patient until a uniform colour and stiffness are achieved

in the combined mass. Preferably, a plurality of small

masses having a variety of colours are available for

successive manipulation with the combined mass. The

kit provides a means by which the difficulty of

manipulative physical therapy may be monitored and

increased. As more small masses are added to the

combined mass, the stiffness increases, requiring more

manipulation to fully blend the masses.

USA

Accession no.687072




24, No.12, 1997, p.T/9-13

NEW TECHNIQUES IN EXTRUSION ANDVULCANISATIONColombo U

Brief details are given of new extrusion and vulcanisation

systems and techniques. Some data are given for the

extrusion of hoses and sections made from silicone rubber

and extrusion lines for the manufacture of elbow hose

blanks. Translated from Gummi Fas Kunst, No.10, 1997,

p.804

Accession no.684804


Biomaterials)

43, No.2, Summer 1998, p.99-107

BIOCOMPATIBILITY RESPONSE TOMODIFIED BAERVELDT GLAUCOMA DRAINSJacob J T; Burgoyne C F; McKinnon S J; Tanji T M;

LaFleur P K; Duzman E

Louisiana,State University

Details are given of the modification of a Baerveldt

glaucoma filtering device made of silicone rubber by

adding porous cellular ingrowth material to the posterior

surface of the drainage plate. These materials were

implanted and their biocompatibility was investigated. 33

refs.

USA

Accession no.682945

Item 173Macplas International

Feb.1998, p.42-3

LIQUID RUBBER

MIR has perfected its injection moulding machines

devoted to liquid silicone rubber, achieving the production

of very small to medium size parts of excellent quality at

competitive prices. LSR has high electrical insulation

properties, high resistance to extremes of temperature,

long life, and is non-toxic, non-allergenic and

biocompatible. LSR brings benefits from advanced

processing technology. Manufacturers can obtain

consistent material savings in terms of scrap, flash and

runners.

MIR SPAEUROPEAN COMMUNITY; EUROPEAN UNION; ITALY;

WESTERN EUROPE

Accession no.682023


19, Nos 1-3, 1998, p.55-60

ANALYSIS OF MRI IMAGES OF A SILICONE

ELASTOMER UNDER DIFFERENT AXIALLOADING CONDITIONSAbel E W; Wheeler K I; Chudek J A; Hunter G; Som F M

Dundee,University

Results are presented of tests on axially tensioned silicone

elastomer tendon spacer samples to determine the

relationship between stress in the material and image

intensity. Images were obtained using spin echo, gradient

echo and magnetic resonance imaging snapshot

techniques. 15 refs.


WESTERN EUROPE

Accession no.681411

Item 175Advanced Materials & Processes

153, No.5, May 1998, p.6

VERY SPECIAL CARS BOAST SPIN-CASTPARTS

Metalcrafters builds one-of-a-kind automobile prototypes.

The company was helped by Chrysler to get its business

off the ground with a request for road-worthy metal-

bodied prototypes. In a bid to find a faster way to produce

low to medium volumes of smaller parts like emblems,

air vents, door handles and dashboard knobs,

Metalcrafters turned to spin casting. Silicone rubber

moulds can produce up to 1500 parts, the company claims.

METALCRAFTERSUSA

Accession no.680676


27, No.19, 20th April 1998, p.6

AMERICAN BIOMED CATHETER GAINSCLEARANCEMcCann J

American BioMed Inc. is reported to have gained

clearance from the FDA for a new silicone rubber

thrombectomy catheter that removes blood clots from

blood vessels. A description is given of the Ahn catheter,

which is expected to be launched in this year’s second

quarter, and a US patent on the device is expected during

the next two months. Its design consists of a three balloon

type, which is said to give surgeons more inflation control

during operations and helps prevent blood spattering when

it’s removed. It is the company’s first internally developed

product to make it through the FDA process on a fully

independent basis, it is reported.

AMERICAN BIOMED INC.USA

Accession no.680170

Item 177Journal of Macromolecular Science C



C38, No.2, 1998, p.143-205

SOME HETEROCYCLIC POLYMERS ANDPOLYSILOXANESLu F

Academia Sinica

A review is given of research into several important

heterocyclic polymers with emphasis given to

polyphenylquinoxalines, polytriazines, polypyrrolones,

polyimides, polyamide-imides, polybenzimidazoles, and

polysiloxanes. Details are given of the synthesis of new

monomers and polymers and the development of new

synthetic routes. The thermal degradation, pyrolysis and

hydrolysis at high temperature are discussed. 162 refs.

CHINA

Accession no.679421

Item 178Journal of Polymer Science : Polymer Physics Edition

36, No.6, 30th April 1998, p.1091-4

ELECTRORHEOLOGICAL FLUID ANDSILOXANE GEL BASEDELECTROMECHANICAL ACTUATOR:WORKING TOWARD AN ARTIFICIAL MUSCLEBohon K; Krause S

Rensselaer Polytechnic Institute

A device has been developed to simulate muscle operation

with the time response of the order of a striated skeletalmuscle. 8 refs.

USA

Accession no.678661

Item 179Modern Plastics International

28, No.4, April 1998, p.64-5

NEW FORMULATIONS, PROCESSTECHNOLOGY PROPEL SILICONEMOULDINGSmock D

Recent advances in polymer formulations and process

technology are propelling a boom in liquid silicone

moulding. It is claimed that companies can attain

significant reductions in total part costs with liquid

injection moulding compared with processing heat-cured

elastomers. One development at GE Silicones is low-

compression-set formulations that open opportunities in

automotive applications for moulders seeking ways to add

value to existing business.


USA; WESTERN EUROPE

Accession no.678253


6, No.2, Feb.1998, p.53

USING LIM TO CREATE BETTER, FASTER,

CHEAPER PROTOTYPES

This article highlights an injection moulding process that

has been developed by Vesta Inc. of the USA, intended

to put an end to lengthy, expensive prototype production

of medical products. “Quick Response” uses liquid

injection moulding (LIM) equipment to mould medical-

grade liquid silicone rubber in low volumes.

VESTA INC.USA

Accession no.677267


87, No.10, Oct.1997, p.46-8

English; German

LIQUID SILICONE RUBBERPohmer K; Schmidt G; Steinberger H; BruendL T;

Schmidt T

In this paper, liquid silicone rubber is placed under the

spotlight, and its properties, processing methods (liquid

injection moulding, multi-component injection moulding,

as well as modifying and finishing), and typical

applications are all considered.

EUROPE-GENERAL; EUROPEAN COMMUNITY; EUROPEAN

UNION; GERMANY; WESTERN EUROPE; WORLD

Accession no.676699


PHOTOCURABLE LIQUID SILICONE RUBBERCOMPOSITIONS FOR TEMPLATING MOTHERMOULDSFujiki H; Sakamoto T


The cured products have a Shore hardness of 20 to 60

and a light transmittance of at least 10% at a wall gauge

of 10 mm. A photocurable liquid resin cast into the mould

is cured with light transmitted by the mould wall.

JAPAN

Accession no.675916

Item 183Macromolecular Symposia

No.127, Feb.1998, p.205-9

COMPOSITE MATERIAL FOR MEDICALAPPLICATIONZamyslov E V; Klochkov V I; Ostrovidova G U

St.Petersburg,Institute of Technology

Details are presented of the preparation of graphite filled

PDMS for medical applications. The physico-chemical

and mechanical properties were determined. Predicted

thromboresistance is discussed. 22 refs.

RUSSIA

Accession no.672899



Item 184Journal of Microencapsulation

15, No.2, March-April 1998, p.227-36

PREPARATION OF SILICONE MICROSPHERESBY EMULSION POLYMERIZATION:APPLICATION TO THE ENCAPSULATION OF AHYDROPHILIC DRUGKedzierewicz F; Darme X; Etienne A; Lemut J;

Hoffman M; Maincent P

Nancy I,University; Dow Corning

The ability of suitable silicone elastomers to encapsulate

hydrophilic compounds in microspheres prepared

according to a multiphase emulsion-polymerisation

process was evaluated. The particle size of the

microspheres could be modified by controlling the usual

emulsification parameters, such as the viscosity of the

different phases, shear rates and surface activity properties

of additives. The encapsulation efficiencies of a

hydrophilic drug, propranolol hydrochloride, were very

high but its release rates were very slow. Osmotic agents

such as glycerol and propylene glycol did not enhance

the release rate, whereas it was slightly increased by both

sodium chloride addition and higher drug loading. 11 refs.


WESTERN EUROPE

Accession no.671085

Item 185Plastiques Modernes et Elastomeres

48, No.7, Sept.1996, p.38/41

French

SILICONE RUBBERS: PROCESSING,PROPERTIES AND APPLICATIONSVasselle J B

The processing, vulcanisation, properties and applications

of hot curing and liquid silicone rubbers are reviewed,

and applications of liquid silicone rubbers in injection

and insert moulding are examined. Statistics are presented

for world consumption of silicone rubbers.

BAYER AG; GE PLASTICSEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

USA; WESTERN EUROPE; WORLD

Accession no.670761


Biomaterials)

43, No.1, Spring 1998, p.1-14

INFLUENCE OF PDMS SURFACE TEXTURE ONHUMAN SKIN FIBROBLAST PROLIFERATIONAS DETERMINED BY CELL CYCLE ANALYSISvan Kooten T G; Whitesides J F; von Recum A F

Clemson,University

The interaction of human fibroblasts with silicone

surfaces was studied using cell cycle analysis. The

potential of cell cycle analysis to serve as an integrated

tool in models for biocompatibility assessment in vitro

is discussed. 27 refs.

USA

Accession no.670595

Item 187Surface Coatings International

81, No.2, Feb.1998, p.89-93

MASONRY PROTECTION WITH SILANES,SILOXANES AND SILICONE RESINSMayer H

Wacker-Chemie GmbH

The use is discussed of silanes, siloxanes and silicone

resins in the masonry protection field, where they act

as binders in decorative coatings or as water-proofing

agents. An overview is presented of applications,

product classes and other modes of action. Applications

considered include silicones in masonry paints and

plasters, where they work as binders, additives or

primers, in construction chemicals, where they work

as water and oil repellents, damp-proofing agents or

stone strengtheners, in in-plant produced materials such

as roof tiles and gypsum boards, where they work as

water repellents for after-treatment applications or for

core-treatment applications. The suitability of a single

product class of these silicone masonry water repellents

based on silanes, siloxanes and silicone resins are

discussed for the above applications.


WESTERN EUROPE

Accession no.669231

Item 188Journal of Biomaterials Applications

12, No.3, Jan.1998, p.258-71

BIOMEDICAL SILICONE ELASTOMERS ASCARRIERS FOR CONTROLLED RELEASEAndreopoulos A G; Plytaria M

Athens,National Technical University

The potential of biomedical siloxane elastomers as

carriers for controlled release of drugs was assessed.

A two-component silicone gel system was used and

various crosslinking agent ratio was applied in order

to produce networks with varying crosslink density.

Swelling experiments in toluene were conducted in

order to evaluate the network characteristics. The

silicone elastomer was loaded with salicylic acid and

propanolol hydrochloride and their delivery in distilled

water was followed. The results showed that release

was almost of zero order for high loading of salicylic

acid, while delivery seemed to be diffusion-controlled

up to a certain limit. The drug concentrations

administered were relatively low if silicone discs were

used, due to the hydrophobic nature of this material.

When membranes with a thickness of 0.1-0.2 mm were

used, on the other hand, the delivery rate was much



higher depending, of course, on the hydrophilic

character of the drug. 18 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; GREECE;

WESTERN EUROPE

Accession no.668285


217, No.3, Dec.1997, p.42-4

SILICONE POLYMERS FOR HIGH-VOLTAGEINSULATORSOwen M J

Dow Corning Corp.

Composite insulators with sheds moulded from silicone

rubber have been used in high-voltage service for nearly

30 years and their popularity is on the rise. Silicone

compounds retain hydrophobicity better than ceramics

or glass, especially in coastal regions and contaminated

areas. Composite insulators are lightweight and can

significantly reduce losses from breakage and vandalism.

Much of the current work on the newest generation of

silicone insulators focuses on surface chemistry to better

understand the effects of long-term ageing and electrical

discharge. 9 refs.

USA

Accession no.668231


METHOD OF MOULDING PRECISION PARTSPennisi R W; Jackson G D; Urbish G F; Megleo L D

Motorola Inc.

This low pressure injection moulding method uses a two-

piece silicone rubber mould having a cavity representative

of the shape of the article to be moulded. The mould is

substantially encased on all sides in a rigid mould box to

prevent deformation of the cavity during the moulding

process. The mould box and the encased mould are placed

in a vacuum chamber and a vacuum is drawn on the

chamber to evacuate the cavity. A predetermined amount

of a reactive mixture is simultaneously mixed and injected

under pressure into the mould to form the article. The

amount of material injected is sufficient to fill the cavity

but not sufficient to distort the cavity. The chamber is

vented and the mould is removed from the mould box.

The mould is then flexed to remove the article therefrom.

USA

Accession no.667840


ROOM TEMPERATURE CURABLEORGANOPOLYSILOXANE COMPOSITIONKimura T; Suzuki K; Teshigawara M


This includes a diorganopolysiloxane terminated with a

hydroxyl group at both terminal ends and having a

viscosity at 25C of 25 to 1,000,000 cSt, an organosilane

having 3 or more hydrolysable groups (ketoxime or

alkenyloxy groups) per molecule, a partially hydrolysed

and condensed product thereof or a mixture thereof and a

thin leaf-like inorganic filler. Cured products based

thereon have good oil resistance and are suitable as FIPG

materials for automobiles.

JAPAN

Accession no.665650


27, No.3, 8th Sept.1997, p.11

NOT DUMB LUCKCampanelli J

This article relates the story of how Kathryn Krotseng

created a patented silicone moulding process (the

inversion moulding system or IMS) to make mannequins.

Silicone mannequins, as opposed to PU dummies, are non-

corrosive, non-toxic, and non-flammable. The IMS

process is described.

MANNI-KIT INC.USA

Accession no.665007

Item 193Plastiques Flash

No.287, Jan./Feb.1996, p.70-1

French

STATE OF THE ART IN MOULDING LIQUIDSILICONES

The Arburg Allrounder 120 V-40 injection moulding

machine and its use in the manufacture of prototype

automotive components from liquid silicone rubbers are

described.

ARBURG MASCHINENFABRIK; WOCO; EOC

NORMALIENEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.663471


70, No.472, Oct.1995, p.379-81

Spanish

MCP VACUUM CASTING SYSTEMMCP Iberia SA

Details are given of the MCP vacuum casting system for

the production of plastics prototypes using silicone rubber

moulds.


WESTERN EUROPE

Accession no.663464




69, No.23, 1st Dec.1997. p.4912-6

RELEASE OF LOW MOLECULAR WEIGHTSILICONES AND PLATINUM FROM SILICONEBREAST IMPLANTSLykissa E D; Kala S V; Hurley J B; Lebovitz R M

Baylor College of Medicine

A series of studies was conducted addressing the chemical

composition of silicone gels from breast implants as well

as the diffusion of low molecular weight silicones and heavy

metals from intact implants into various surrounding media,

namely lipid-rich media (soy bean), aqueous tissue culture

medium (modified Dulbecco’s medium, DMEM), or an

emulsion consisting of DMEM plus 10% soy oil. The rates

at which LM-silicones and platinum leaked through the

intact implant outer shell into the surrounding media under

a variety of conditions were studied. 14 refs.

USA

Accession no.662917


27, No.8, 17th Nov. 1997, p.10

NEW COMPANY LAUNCHES NON-METALHEAD GASKETMeyer B

A high temperature, non-metallic head gasket has been

developed that is competitive with metal gaskets.

Developed by William A. Clarke, a former Ford Motor

engineer, it consists of silicone rubber, which he describes

as a pre-ceramic polymer, and a key part of the material

is said to be the fibre reinforcement from Owens Corning

which is claimed to have unusually low thermal

expansion. Clarke’s company is called Gasket King: A

Briefer Clark Company L.L.C., and is currently operating

by using excess capacity at Edler Industries’ plant under

a government program to fund the development of

peacetime products at factories primarily geared toward

defence work.

GASKET KING: A BRIEFER CLARK CO.LLC;

DELER INDUSTRIESUSA

Accession no.662690

Item 197Medtec. Conference proceedings.

Amsterdam, 21st-23rd Oct.1997, Session 102, Thomas,

p.1-6. 6S

BIOPERFORMANCE OF SILICONEMATERIALS IN BIOMEDICAL APPLICATIONSThomas X; Briquet F

Dow Corning Corp.

(Canon Communications Inc.)

The use of polymers for biomedical applications has been

dramatically expanding during the last decades. As

biomaterials, they now play an essential role in helping

healthcare workers to save life, alleviate pains and improve

the general quality of life. Several guidelines and test methods

ensure that adequate information exists regarding the function

of the device and its toxicity profile to define its risk to benefit

ratio. However, beyond the legal requirement, which allows

to qualify biocompatible materials against industrial ones,

there is still an opportunity for performance improvement

in specific applications and thus the differentiation of some

biomaterials to offer substantial benefits. The concept of

BioPerformance is introduced and illustrated with three

comparative examples which highlight the unique

contribution of recognised silicone products to selected

biomedical applications. 13 refs.


WESTERN EUROPE

Accession no.662523


37, No.4, 15th Dec.1997, p.539-47

EFFECT OF SUBCUTANEOUS SILICONERUBBER IMPLANT WITH SHALLOW SURFACEMICROGROOVES ON SURROUNDING TISSUESIN RABBITSden Braber E T; de Ruijter J E; Jansen J A

Nijmegen,University

It has been suggested that during wound healing,

microtextured surfaces can alter events at the interface

between implant surface surface and surrounding tissues.

To investigate this phenomenon, smooth and microtextured

silicone rubber implants are implanted subcutaneously in

rabbits for 3, 7, 42 and 84 days. The textured implants possess

parallel surface microgrooves and ridges with a width of

2.0, 5.0 and 10.0 micrometer. All grooves have a depth of

approximately 0.5 micrometer. SEM observation shows

fibroblasts, erythrocytes, lymphocytes, macrophages, fibrin

and collagen on all implant surfaces after three and seven

days. After 42 and 84 days only little collagen, a small number

of fibroblasts, but no inflammatory cells are seen on the

implant surfaces. The fibroblasts are not oriented along the

surface grooves on all textured surfaces. Three-dimensional

reconstruction of CLSM images and LM images show no

significant differences between the thickness of the capsules

surrounding the smooth and those surrounding the

microgrooved implants. In contrast, LM does show a

significantly lower number of inflammatory cells and a

significantly higher number of blood vessels in the capsules

surrounding the microgrooved implants. Differences

between the 2.0, 5.0, and 10.0 (m grooved implants are not

detected. Results concerning capsule thickness suggest that

the depth of the grooves is not sufficient to facilitate

mechanical interlocking, but the cause for the observed

differences in inflammatory response and number of blood

vessels remains unclear. 29 refs.



Accession no.662315




37, No.4, 15th Dec.1997, p.534-8

ADJUVANCY EFFECT OF DIFFERENT TYPESOF SILICONE GELNaim J O; Ippolito K M L; van Oss C J

Rochester,General Hospital; Buffalo,University

Women with silicone gel-filled breast implants (SBIs) are

likely to be at a slightly higher risk of developing an

autoimmune-like syndrome. This risk, although small,

may be associated with the immunological adjuvancy

property of the silicone gel. However, not all silicone gels

are chemically formulated exactly the same and their

adjuvancy behaviour may vary. This e adjuvant effect of

three different lots of silicone gel is compared in rats,

using ovalbumin (OVA) as the test antigen. Test bleeds

are taken at 21, 48, 62 and 84 days post immunisation

and the rat sera are analysed for anti-OVA antibodies by

enzyme-linked immunosorbent assay (ELISA). A delayed

type hypersensitivity (DTH) test is performed on all the

treated rats beginning at 14 post-immunisation days. The

results show that silicone gel No.3 (McChan lot no.

S0400488) produces the highest mean anti-OVA antibody

titre followed by silicone gel No.1 (DC lot No.

HHO19581) and silicone gel No.2 (McChan lot No.

13P9339). The DTH results show that rats treated with

silicone gel 1 and 3 have a clear positive response, whereas

silicone gel 2 causes only a minimal response. These

results demonstrate the immunological adjuvancy

difference among three types of silicone gel. The chemical

composition of each of these silicone gels, that would

help explain these results, is yet to be determined. 12 refs.

USA

Accession no.662314

Item 200152nd ACS Rubber Division Meeting, Fall 1997.


Cleveland, Oh., 21st-24th Oct.1997, Paper 96, pp.32.

012

BASIC STUDY OF CONTINUOUS ULTRASONICDEVULCANIZATION OF UNFILLED SILICONERUBBERDiao B; Isayev A I; Levin V Yu

Akron,University,Inst.of Polym.Engineering

(ACS,Rubber Div.)

Unfilled polydimethyl siloxane vulcanisates were

ultrasonically devulcanised under several processing

conditions in an extruder with an ultrasound die

attachment. Gel fraction and crosslink density

measurements indicated that the rubber was partially

devulcanised. The cure behaviour, rheological properties

and structural characteristics of the devulcanised and

virgin rubbers were studied, and the mechanical properties

of revulcanised samples were compared with those of the

virgin rubber. GPC results implied that the creation of a

branched structure in the network was possible after

devulcanisation. Revulcanisation of rubbers devulcanised

under optimal conditions gave mechanical properties

better than those of the virgin rubber. Blends of

devulcanised and virgin rubbers showed the same tensile

strength and modulus as the virgin rubber but higher

elongation. 16 refs.

USA

Accession no.659540


ONE PART ROOM TEMPERATUREVULCANISING COMPOSITION HAVING BOTHA HIGH RATE OF EXTRUSION AND LOW SAGDziark J J; Pink M R; Martucci J P


A base mixture of a diorganopolysiloxane and an end

stopping crosslinking ketoximosilane are reacted prior to

being added to a first injection port along an extruder. An

inorganic filler is added to the base mixture at a second

injection port along the extruder, an M stopped silicone

fluid is partitioned into two parts and the first part of the

M stopped fluid is added to the filler containing base

mixture at a third injection port at the middle of the

extruder. A tin catalyst, an adhesion promoter and the

second part of the M stopped fluid is added at a fourth

injection port along the extruder and the mixture is

extruded towards the extruder exit port.

USA

Accession no.658578

Item 202152nd ACS Rubber Division Meeting, Fall 1997.


Cleveland, Oh., 21st-24th Oct.1997, Paper 30, pp.11.

012

LR3014 SERIES: A NEW FAMILY OF LIQUIDSILICONE RUBBER FOR OUTSTANDING, NOPOST CURE PERFORMANCE IN OIL SEALINGAPPLICATIONSJohnson T


(ACS,Rubber Div.)

Applications of liquid silicone rubber (LSR) in injection

moulded automotive seals and gaskets are examined, and

results are presented of a study which was undertaken to

compare the performance of a conventional LSR

compound with that of a grade in the Elastosil LR3014

series (Wacker Silicones) which employs a method of

controlling aftercure without post curing. This new grade

showed advantages in terms of reduced compression set,

greater heat resistance, equivalent resistance to motor oils

and equivalent to substantially improved resistance to

different types of transmission fluids.

USA

Accession no.658284



Item 203Biomedical Materials

Oct. 1997, p.10-11

SILICONE IMPLANTS

The use of silicone in testicular implants has declined

following the moratorium on the use of silicone breast

implants by the FDA, it is reported. Problems regarding

the presence of impurities in the silicone polymer such

as silica which was used to harden the elastomer, platinum

which acted as the catalyst, and a variety of organic and

inorganic compounds including talc have been implicated

in inciting an inflammatory response in the recipient

which is difficult to avoid, claim scientists. In addition,

the rarity of connective tissue diseases and the long latency

period mean that the definitive epidemiological study to

detect an association between silicone implants and

connective tissue disease, may never be performed, it is

argued.

USA

Accession no.655797


87, No.9, Sept. 1997, p.41-2

LIQUID SILICONE RUBBER (LSR) CAPSEmmerichs H; Giesler D

EOC Normalien

The injection moulding of liquid silicone rubber caps

using a 16 cavity mould with a cold runner system, is

described. The cap is for protecting the power door lock

switch in a car from moisture and dirt. It is stated that the

low viscosity of liquid silicone rubber requires special

precautions with respect to design and operations of

injection moulds, and the use of a standard cold runner

system is said to simplify processing. It is advised that

care should be taken to provide proper thermal separation

of the runner system from the part forming sections of

the mould, but that demoulding of parts with small

undercuts should not cause problems. Details are given

of the mould design and the runner system, and part

release/ejection.


WESTERN EUROPE

Accession no.655713


36, No.4, 15th Sept.1997, p.487-97

EFFECT OF SALINE EXPOSURE ON SURFACEAND BULK PROPERTIES OF MEDICAL GRADESILICONE ELASTOMERSKennan J J; Peters Y A; Swarthout D E; Owen M J;

Namkanisorn A; Chaudhury M K

Dow Corning Corp.; Lehigh University

Medical grade silicone elastomers are subjected to

accelerated ageing in saline to verify the hydrolytic

stability of the elastomer. Tensile strength, elongation at

break and elastomer stress measured at 100% or 200%

elongation do not change significantly for peroxide-cured

sheeting aged in 37 deg.C or 100 deg.C saline for 45 h.

Under similar conditions, hydrosilylation cured sheeting

behaves similarly; however, increases in stresses

measured at 100% and 200% elongation are observed after

the first hour of treatment. After the first hour, the physical

properties remained relatively constant. On either

elastomer, initial liquid drop advancing contact angles for

water ranges from 110-115 deg., and in no case is a change

of more than 6 deg. observed as a result of ageing in saline

for 45 h at temperatures up to 97 deg.C. The high

advancing angles indicated that the surface remains

largely hydrophobic. Initial liquid drop receding contact

angles range from 48-64 deg., with receding contact

angles being more sensitive to accelerated ageing, in one

case decreasing to 14 deg. Similar decreases in receding

contact angle are observed in PE subjected to the same

accelerated ageing conditions. Decreases in receding

contact angle are not considered to be indicative of

extensive hydrolysis. The observed contact angle

phenomena are consistent with current views of contact

angle hysteresis being caused by surface heterogeneity.

There is no evidence of significant surface or bulk siloxane

hydrolysis under these accelerated ageing conditions. 19

refs.

USA

Accession no.654416

Item 206Journal of Materials Science.Materials in Medicine

8, No.10, Oct.1997, p.631-5

CONDITIONING FLUID INFLUENCES ON THESURFACE PROPERTIES OF SILICONE AND PUPERITONEAL CATHETERS: IMPLICATIONSFOR INFECTIONGorman S P; Jones D S; Mawhinney W M; McGovern

J G; Adair C G


Details are given of the adherence of Staphylococcus

epidermidis to PU and silicone peritoneal catheters in the

presence and absence of proteinaceous conditioning film.

The effects of these conditioning films on the surface

properties of the biomaterials were investigated. Bacterial

adherence was examined using a radiometric adherence

assay. 25 refs.


WESTERN EUROPE

Accession no.653384

Item 207International Polymer Processing

12, No.2, July 1997, p.174-81

DETERMINATION OF INTER-RELATIONSHIPSBETWEEN PROCESSING CONDITIONS ANDPROPERTIES OF INJECTION MOULDED



SILICONE RING USING EXPERIMENTALDESIGNBarbaroux M; Stalet G; Regnier G; Trotignon J-P

Dow Corning France SA; Ecole Nationale Superieure

des Arts et Metiers

The effects of injection moulding parameters on the

mechanical-physical properties of a liquid silicone rubber

(LSR) injection moulded ring are studied through an

experimental design. The effects of the changeover point

(volume or pressure driven), runner (hot or cold), hold

pressure, mould temperature and injection flow rate

variations are evaluated based upon the responses related

to both material properties (ultimate elongation and tensile

stress in a tensile test, swelling in hexane, hardness,

density) and ring properties (cross sectional diameter,

weight, volume). It is determined that ring density is not

dependent on the parameters studied. The mould

temperature appears to be a very influential parameter,

especially concerning material characteristics: it affects

the swelling ratio, hardness, and ultimate properties, but

weight and volume are only affected when the cold runner

is used. The hold pressure has an effect on both the weight

and volume of the ring. The type of changeover used

(volume or pressure) has no effect when a cold runner is

used, but affects the weight, volume and ultimate

properties of the ring, when a hot runner is used. The

injection flow, rate does not affect the observed

characteristics. 20 refs.


WESTERN EUROPE

Accession no.652454


July 1997, p.12

SILICONE IMPLANTS ARE AT CENTRE OFFRESH CONTROVERSY

This abstract describes the problems associated with

assessing the long-term risks of silicone implants. The

article includes information on the current controversy

over possible adverse health effects of silicone breast

implants and the carcinogenical potential associated with

lifetime tissue exposure to various forms of silicone

polymers.

US,FOOD & DRUG ADMINISTRATIONEUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA;

WESTERN EUROPE

Accession no.651091


8, No.7, July 1997, p.465-70

OXYGEN-CROSSLINKED POLYSILANE: NEWCLASS OF SI-RELATED MATERIAL FORELECTROLUMINESCENT DEVICESHiraoka T; Majima Y; Murai S; Nakano Y; Hayase S

Toshiba Corp.

The preparation and optical properties of the novel

silicone-related material, oxygen-crosslinked polysilane,

are investigated. The oxygen-crosslinked polysilane is

prepared by the thermal annealing of the precursor

polysilane bearing alkoxyl groups. The

photoluminescence, consisting of a broad visible band at

about 440 nm and a relatively sharp band at about 360

nm, is observed at room temperature. The relative

intensities of the visible emission are changed during

crosslinking. Visible emission is greatly affected by the

steric hindrance of the alkoxyl groups of the precursor.

Visible electroluminescene (EL) is also observed

uniformly from the EL cell consisting of the oxygen-

crosslinked polysilane film sandwiched between the Al

electrode and indium-tin oxide (ITO) electrode. The

current densities of the EL cell increase with an increase

in the oxygen-crosslinking. 15 refs.

JAPAN

Accession no.648094

Item 210Chemistry & Industry

No.13, 7th July 1997, p.498

NO EVIDENCE OF SILICONE IMPLANTHEALTH RISK

A new study from the American Academy of Neurology

has reported that there is no evidence to show that silicone

implants cause disease. The article supplies details of the

report’s findings, which could shatter the hopes of

thousands of women who are suing for damages over the

alleged link between implants and ill health.

AMERICAN ACADEMY OF NEUROLOGY; DOW

CHEMICAL CORP.; DOW CORNING CORP.USA

Accession no.647598


SILICONE ELASTOMER SEALS FORMOULDED PLASTIC PARTSHetherington R C

New Southland Inc.

A process is described for bonding a silicone elastomer

seal to a moulded plastic part, such as an electrical

connector. Prior to moulding, aromatic polyamide pellets

are pretreated with an aminofunctional silicone fluid and

the pretreated pellets are then moulded in the presence of

moisture at a temperature sufficient to chemically graft the

amino function of the silicone fluid to the aromatic carbonyl

function of the aromatic polyamide and to form silanol

groups within the aminofunctional silicone fluid. The

moulded part is coated with an organofunctional

alkoxysilane having at least one vinyl group and then heated

in the presence of moisture to convert the alkoxysilane into

a siloxane polymer with vinyl and silanol groups. These

silanol groups then react with the silanol groups of the



aminofunctional silicone fluid. A liquid silicone elastomer,

which contains sufficient Si-H groups to react with vinyl

groups contained in the siloxane polymer formed from the

alkoxysilane, is applied to the coated moulded plastic part,

which is then heated to form a covalent bond between vinyl

groups of the siloxane polymer and Si-H groups of the

elastomer, the liquid silicone elastomer forming a seal,

which is bonded to the moulded plastic part.

USA

Accession no.647462

Item 212Molecular Crystals & Liquid Crystals

Vols 294 & 295, 1997, p.127-32

LIGHT-EMITTING DIODES BASED ONSILICON-BACKBONE POLYMERSSuzuki H

NTT

Electroluminescence characteristics were measured and

analysed as a function of temperature, electron injecting

electrodes, and the concentration of defects at the

polymethylphenylsilane-electron injecting electrode

interface. Applications to polymethylphenylsilane light

emitting diodes are discussed. 16 refs.

JAPAN

Accession no.647206


8, No.6, June 1997, p.351-4

POLYSILOXANE GEL WITH LOWCROSSLINKING DENSITY FOR MAKE-UPCOSMETICSKobayashi R; Yabe S; Nomura T

Kose Corp.

The mechanism whereby a crosslinked silicone having a

specific crosslink density was swollen in the presence of a

silicone oil having a low viscosity to form a stable gel was

applied to the manufacture of cosmetic foundations.

Optimum conditions that provided favourable properties

and satisfactory organoleptic sensation were studied.

Polymethylhydrogensiloxanes with a low crosslink density

were prepared by subjecting alpha,omega-divinyl-

polydimethylsiloxane to addition polymerisation. The

viscoelasticities of the gels formed from the resultant

products and silicone oil were investigated. Based on the

results, it was concluded that the most suitable product was

a low crosslink density material obtained by adding

alpha,omega-divinylpolydimethylsiloxane to polymethyl-

hydrogensiloxane having an average molec.wt. of 2.5 kDa

under conditions in which the concentration of

dimethylpolysiloxane was 60%. This product provided an

enhanced viscosity at a reduced solids content. 5 refs.

JAPAN

Accession no.645630

Item 214Advanced Materials

9, No.9, 4th July 1997, p.741-6

STABILITY OF MOULDEDPOLYDIMETHYLSILOXANEMICROSTRUCTURESDelamarche E; Schmid H; Michel B; Biebuyck H

IBM Corp.

One aspect of the use of elastomeric materials for the

formation of the stamps central to existing demonstrations

of microcontact printing and micromoulding in capillaries

(MIMIC) is examined: the stability of features in

elastomeric stamps to the processes of their formation and

subsequent application. The key function of elastomeric

stamps is to provide a pattern of relief on the surface of a

flexible solid used to transfer or mould the shape of material

in its image. Fabrication of a stamp requires its replication

from a master. Liquid polydimethylsiloxane (PDMS) is

poured on top of the master, which is formed in photoresist,

directly in silicon, or in some other material. The low-

energy siloxane fluid fills the crevices of the master,

forming a negative replica of the surface. Further

crosslinking of the siloxane by light-initiated or metal-

catalysed reaction results in an elastomeric solid that

preserves on its surface - in the best cases - an accurate

record of the topology after its separation from the master.

The pattern of reliefs in the surface of the stamp is then

useful in transferring inks to a substrate by contact between

raised regions of the stamp and the surface of the substrate.

Alternatively, these reliefs act as moulds or conduits for

solids or liquids and thus as a direct template to form

patterns in these materials. 16 refs.


Accession no.645230

Item 215NRC ’96. Conference proceedings.

Helsinki, 23rd-24th May,1996, paper 9. 8

SILICONE RUBBER IN SPECIALAPPLICATIONSDietl S

Wacker-Chemie GmbH

(Finnish Association for Rubber Technology; Nordic

Council of Rubber Technology)

Silicone rubber is well-known as a special elastomer for

the solution of problems in individual applications. Its

unique combination of outstanding properties leads to

hundreds of cases where silicone rubber is the only choice.

On account of its versatility, silicone rubber may be

tailored to the demand of special tasks. The lecture covers

well-known applications as well as fascinating new ones.

Silicone rubbers can be used in a number of applications,

including high-temperature, low-temperature, electrical,

flame retardant, health care, food-contact, baby-care,

household, construction and automotive applications.


WESTERN EUROPE

Accession no.641386




35, No.4, 15th June 1997, p.505-11

THEORETICAL ANALYSIS OF HYDROLYSISOF POLYDIMETHYLSILOXANE(PDMS)West J K

Florida,University

The hydrolysis of PDMS, commonly used in breast

implants, was theoretically modelled using a semi-

empirical quantum mechanical model (AM1). The

activation barrier for removing a methanol monomer was

found to be +82 Kcal/mol, while the removal of a

methane monomer was +41 Kcal/mol. Using the same

AM1 method, hydrolysis of the -Si-O-Si- bond was also

modelled for pentasilicic acid and 1,1,3,3-

tetramethyldisiloxane-1,3-diol. The barrier to the

removal of a silicon-containing tetrahedron for both

studies was found to be +27 Kcal/mol. This was

approximately one and a half times smaller than the

energy of that needed to remove a methyl group. The

pentacoordinated silicon-activated transition state for

hydrolysis of PDMS could provide an energetically

favourable pathway for development of a surface that

would enhance chemisorption of charged protein

molecules and such a pathway map could show up in

NMR studies of the hydrolysis of PDMS. 28 refs.

USA

Accession no.640133

Item 217151st ACS Rubber Division Meeting, Spring 1997,


Anaheim, Ca., 6th-9th May 1997, Paper 88, pp.24. 012

NMR OF TISSUES EXPOSED TOPOLYSILOXANE GELSGarrido L

Massachusetts General Hospital; Harvard Medical

School

(ACS,Rubber Div.)

The migration of polysiloxanes from polysiloxane gel

filled breast implants to local and distant sites in living

systems was studied by NMR spectroscopy. Tissues from

animals and humans exposed to the implants were studied

in-vivo using proton NMR localised spectroscopy and in-

vitro with proton and silicon-29 magic angle spinning

NMR spectroscopy. The results showed that free

polysiloxanes present in the implants migrated to

surrounding tissues and distant organs such as the liver.

In addition, silicon-29 NMR spectra of metabolically

active tissues (liver) showed the presence of chemically

unchanged polysiloxanes and other silicon-containing

compounds (silica), suggesting that these polymers were

biodegradable. 45 refs.

USA

Accession no.639065




ADVANTAGES OF SILICONE ELASTOMERS INTHE CONSTRUCTION OF ROLLERSLapsley T; Dickson S

American Silicones

(ACS,Rubber Div.)

An examination is made of the range of properties

obtainable in rollers covered with silicone rubbers.

USA

Accession no.639054




SILICONE RUBBER APPLICATIONS: WHYSILICONES ARE USEDFinney D; Papa J

General Electric Co.,Silicone Products Div.

(ACS,Rubber Div.)

Uses of silicone rubbers in automotive and aerospace

applications, high voltage insulators and business machine

components are reviewed, and the reasons for selecting

silicone rubbers for such applications are discussed. 3 refs.

USA

Accession no.639044

Item 220Antec 97. Volume I. Conference proceedings.

Toronto, 27th April-2nd May 1997, p.308-14. 012

POLYFLOW: TREATISE ON INVERSE DIE/MANDREL DESIGN FOR HIGH CONSISTENCYSILICONE ELASTOMERAndrejewski D A

Dow Corning Corp.

(SPE)

To date, manufacturing experiences low production yields

when extruding complex cross-sections with high

consistency silicone rubber. In the extrusion process, shear

is imparted and introduced to the material, causing both

shear thinning and elastic effects which make the die/

mandrel design uncertain. Computational Fluid Dynamic

methods (Polyflow) were utilised to model the flow

characteristics of the material through the die/mandrel to

determine their proper shape with respect to the required

extrudate. Non-linear viscoelastic constitutive models

correlating rheology with the actual flow dynamics were

utilised in the software to achieve this end. The die/

mandrel design developed through the modelling

techniques demonstrated their invaluable need by

boosting production rates as high as 167%, and decreasing

waste and set-up time 18-fold respectively. Finally, the



process developed should be utilised to improve existing

and future designs where complex profiles cause long set-

up times and high scrap rates. 5 refs.

USA

Accession no.636428


18, No.8, 1997, p.635-41

PHYSICOCHEMICAL PROPERTIES OF ARIFAMPICIN-RELEASINGPOLYDIMETHYLSILOXANE SHUNTSchierholz J M

Cologne,University

Results of studies of the above are presented and

discussed, particular attention being paid to the cohesion

energy (solubility parameter) of the polydimethylsiloxane

network and rifampsin, controlled delivery of rifampsin

from the silicone network, mechanical properties of the

conventional and modified silicone shunt, differential

calorimetric determinations of drug, polymer and the

drug-polymer system, and SEM of the polymer and the

polymer-rifampsin system. Rifampsin is a competitive

inhibitor of bacterial RNA polymerase. 30 refs.


WESTERN EUROPE

Accession no.634645

Item 222China Rubber Industry

44, No.4, April 1997, p.233-6

Chinese

STUDY ON RUBBER COMPOUNDS OF HIGHVOLTAGE CAP AND WEDGE FOR TELEVISIONSETWu Shishan; Dou Qiang; Liu Gang; Ma Liming

Nanjing,Institute of Chemical Technology; Nanjing

Jiangpu Dougang Plastics Factory

Silicone rubber compounds of high voltage cap and wedge

for colour television sets were developed. The effect of

flame retardant and filler on the physical properties, flame

retardance and electrical properties was investigated. The

results showed that good flame retardance was obtained

with antimony oxide/DBDPO blend flame retardant

system, 3-4 phr of silica being adequate. The formulation

developed included silicone rubber (151 mix type) 100

parts, 2,5-dimethyl-2,5-bis(tert-peroxy)hexane 1 part,

antimony oxide 2 parts, DBDPO 4 parts, silica 4 and 3

parts, respectively, for high voltage cap compound and

wedge compound. 3 refs.

CHINA

Accession no.632501


26, No.14, 24th Feb.1997, p.19

MOHAWK TURNING OUT RUBBERCOMPONENTSWhitford M

Mohawk Plastics Inc. is a manufacturer of thermoplastic

and thermoplastic elastomer gasket carriers for car

makers. Details are given of its expansion plans which

involve the adding of liquid silicone injection moulding

machines for engine gasket construction. The company

is currently increasing capacity for carriers at its Marine

City factory and plans to double floor space there.

MOHAWK PLASTICS INC.USA

Accession no.631852

Item 224Plastics and Rubber Asia

12, No.69, March 1997, p.32

LIQUID SILICONE DEMONSTRATES SAVINGPOWER

Advantages of the use of liquid silicone rubber Silopren

LSR were demonstrated at Aseanplas, by Bayer. Using

an adapted Engel 90 tonnes clamping force injection

moulding machine, a cycle time of 22 seconds was

achieved to produce injection moulded parts. LSR is

reported to be popular in Asia, with applications in baby

bottle teats and keyboards, and Bayer hopes that the powerindustry will use it in the future to replace porcelain high

voltage insulators.

BAYER AG

Accession no.631813


69, No.7, 1st April 1997, p.1267-72

DETECTION AND CHARACTERIZATION OFPOLYDIMETHYLSILOXANES IN BIOLOGICALTISSUES BY GAS CHROMATOGRAPHY(GC)/ATOMIC EMISSION DETECTION(AED) ANDGC/MASS SPECTROMETRY(MS)Kala S V; Lykissa E D; Lebovitz R M

Baylor College of Medicine

A sensitive method was developed for detection,

characterisation and quantification of low molec.wt.

silicones using GC/AED and G C/MS. Using this

approach, twelve distinct silicon-containing peaks were

detected in polydimethylsiloxane oil by GC/AED, and

GC/MS analysis was used to identify some of the

abundant peaks by MS spectral matching. The described

methodology was shown to have the potential to allow

the measurement of less than 1 micro g of silicone/g of

biological tissue. 8 refs.

USA

Accession no.631642




179, No.4, April 1997, p.27-8

SILICONES STILL A GROWING AREAWhite L

The major French silicone sealant supplier, Rhone

Poulenc, says is is focusing on innovation and new

products. It is particularly optimistic about prospects for

its new generation of water-based silicone sealants. Dow

Corning estimates growth in silicone sealants as averaging

about 5-6%, with regional variations. The sealants

business is heavily dependent on the health of the

construction sector. Europe and Japan, for example, are

experiencing poorer conditions than others for sealant

sales.


Accession no.631579

Item 227European Plastics News

24, No.4, April 1997, p.24-5

FLEXIBLE SOLUTIONSAnscombe N

With the correct processing equipment, liquid silicone

rubbers can be easily moulded into a huge variety of

products. Standard injection moulding machines need to

be modified before they can be used for LSR processing.This is done with relative ease and involves changes to

the dosing equipment, barrel, screw and mould nozzles.

MANNESMANN DEMAGEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.630218


METHOD AND DEVICE FOR CUSHIONINGLIMBSBracken R L; Winn R A; Riley N L

Schering-Plough HealthCare Products Inc.

A soft, tacky polysiloxane elastomer, which has a

tackiness of 10 to 450 grams, as determined by a polyken

probe tack tester, or 0 to 10 cm, as determined by a rolling

ball tack tester, and a tensile strength of 0.14 to 5.52 mega

Pascals (20 to 800 pounds/sq.in.), a minimum elongation

of 250 to 1100% and a tear strength of 0.88 to 35.2 kN/m

(5 to 200 pounds/sq.in.) is disclosed. It can be made into

various cushioning devices with or without a topcover,

including an arch support pad, a metatarsal pad, a heel

cushion, sheet padding, a full-length insole, a three quarter

length insole, a half insole, a toe-crest pad, a heel liner,

an elbow pad, a corn pad, a callus pad, a blister pad, a

bunion pad or a toe pad.

USA

Accession no.629328

Item 229British Plastics and Rubber

March 1997, p.21-2

PROCESSING AS A LIQUID CUTS THE COSTOF SILICONE RUBBER

Liquid silicone rubber is a transparent rubber material

with degrees of hardness between 20 and 90 Shore A,

which crosslinks rapidly when mould temperature reaches

about 200C. The 2KM Silco-Mix metering system from

Prodef Engineers permits both material components to

be dosed directly from their original drums. Demag

Ergotech 25 and 35 tonne injection moulding machines

with a specially designed screw and barrel are now

available for LSR moulding. Processing requirements are

discussed.

PRODEF ENGINEERS LTD.; MANNESMANN

DEMAG; MIR SPA; SILICONE ALTIMEX LTD.WESTERN EUROPE-GENERAL

Accession no.628609


TWIN-SCREW EXTRUSION OF SILICONEDOUGHS SUITED FOR SIH/SIVI RTVCOMPOSITIONSLe Blanc L; Pagliari R

Rhone-Poulenc Chimie

Silicone doughs suitable for incorporation into

diorganopolysiloxane compositions crosslinkable into

elastomeric state are rapidly and conveniently formulated

by continuously and simultaneously individually

introducing along the longitudinal axis of a twin screw

extruder, via a plurality of longitudinally spaced discrete

inlet entries, and twin screw extruding (a) a

polydiorganosiloxane oil having a viscosity at 25C of less

than 500000 mPa.s and containing at least two given

functional groups per molecule, (b) water, (c) silica, and

(d) a polysilazane which is liquid under normal conditions

of temperature and pressure.


WESTERN EUROPE

Accession no.628335


9, No.2, Feb.1997, p.147-9

REPLICA MOULDING USING POLYMERICMATERIALS: PRACTICAL STEP TOWARDNANOMANUFACTURINGXia Y; McClelland J J; Gupta R; Qin D; Zhao X-M;

Sohn L L; Celotta R J; Whitesides G M

Harvard University; US,National Inst.of Standards &

Technology; Princeton,University

Details are given of the technique of replica moulding

for manufacturing nanostructures with emphasis given



to the use of elastomeric masters. Data are given for

PDMS, PMMA, and PU. 13 refs.

USA

Accession no.626453


FLAME RETARDANT SILICONECOMPOSITIONSHironao Fujiki; Masayuki Ikeno; Hiroyasu Hara;

Kasuyasu Satoh


To a silicone composition comprising (A) an

organopolysiloxane having at least two alkenyl groups in

a molecule, (B) an organohydrogenpolysiloxane having

at least two hydrogen atoms each directly attached to a

silicon atom in a molecule, and (C) a platinum catalyst,

(D) a compound having a phenyl group and a secondary

or tertiary amino group directly attached thereto is added

to render the composition flame retardant. The

composition cures into a transparent product having

improved flame retardancy meeting the UL standard and

is suitable for use in the protection of electronic parts

like IC’s and hybrid IC’s.

JAPAN

Accession no.625227


ABRASION RESISTANT SILICONEWEATHERSTRIP COATINGGriswold R M; Lin S B


A water reducible weatherstrip coating comprises a two

or three component system comprising a silicone emulsion

base, a bath-life extender, and a crosslinking composition.

USA

Accession no.624955

Item 234Injection Moulding International

1, No.1, Nov./Dec.1996, p.36

INTELLIGENT REDESIGN CUTS COST INHALFNeilley R

A computer keyboard mat, situated under the keys, flexes

to transmit the signal then returns the key to its start

position. Traditionally, keyboard mats have been

compression moulded in NR. Starlim GmbH, a liquid

injection moulder of liquid silicone rubber, has redesigned

the part, cutting the finished part weight by more than

half and significantly improving the mat’s performance

and durability. The new design is a pattern of domes and

thin connecting strips.

STARLIM GMBHEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.624824

Item 235Plastics and Rubber Weekly

No.1676, 7th March 1997, p.20

SEMINAR SELLS LIM

GE Silicone and Mannesmann Demag Hamilton recently

joined forces to introduce thermoplastic moulders to the

benefits of liquid injection moulding of silicone

elastomers. From a cost point of view alone, switching

from processing thermoplastics to silicone LIM is a

smaller hurdle than from conventional heat cure

elastomers to LIM. Production of an automotive spark

plug connector was used to demonstrate that silicone LIM

can be carried out on relatively lightly modified moulding

equipment.

GE SILICONES; MANNESMANN DEMAG

HAMILTON LTD.EUROPEAN COMMUNITY; EUROPEAN UNION; UK;

WESTERN EUROPE

Accession no.624534


34, No.2, Feb.1997, p.201-10

ADHESION TO SILICONE RUBBER OF YEASTSAND BACTERIA ISOLATED FROM VOICEPROSTHESES: INFLUENCE OF SALIVARYCONDITIONING FILMSBusscher H J; Geertsema-Doornbusch G I; van der Mei

H C

Groningen,University

Adhesion of two streptococcal, staphylococcal, Candida

albicans and Candida tropicalis strains, isolated from

explanted voice prostheses was investigated to silicone

rubber with and without a salivary conditioning film in a

parallel-plate flow chamber. Within each microbial pair

of one species, the strain with the most negative zeta

potential adhered most slowly to negatively charged

silicone rubber. No other clear relationships were obvious

between adhesion to silicone rubber and microbial zeta

potentials or cell-surface hydrophobicities, as by water

contact angles. 37 refs.



Accession no.622299

Item 237Plast’ 21

No.47, Nov.1995, p.85-6

Spanish

PRODUCTION OF PLASTICS AND METALPROTOTYPES BY VACUUM CASTING



Ferrandiz S

AIJU

An account is given of techniques used by AIJU of Spain

for the vacuum casting of plastics and metal prototypes

for the toy industry using silicone rubber moulds.


WESTERN EUROPE

Accession no.621102

Item 238Materie Plastiche ed Elastomeri

No.9, Sept.1995, p.524-7

Italian

YEAR OF EXTRUSION

A survey is made of developments by GE Plastics in

engineering plastics grades for extrusion and injection

moulding. Uses of these materials in electrical,

telecommunications, lighting and automotive applications

and domestic appliances are examined. Details are also

given of silicone polymer coatings, liquid silicone rubbers

and silicone rubber gels developed by GE Silicones.

GE PLASTICS; DELPHI INTERIOR & LIGHTING

SYSTEMS; GE SILICONESUSA

Accession no.621090


17, No.23, 1996, p.2265-72

TISSUE RESPONSE TO COMMERCIALSILICONE AND POLYURETHANEELASTOMERS AFTER DIFFERENTSTERILISATION PROCEDURESZhang Y Z; Bjursten L M; Freij-Larsson C; Kober M;

Wesslen B

Lund,University

A silicone and a polyurethane elastomer were studied with

regard to correlations between the chemical and physical

compositions of the polymer surfaces and the biological

response on implantation. Test specimens of the materials

were manufactured according to standard procedures. The

specimens were implanted into rats for 10 and 90 days.

Before implantation, the polymers were sterilised by beta

irradiation, ethylene oxide sterilisation and steam

sterilisation. The polymers were characterised before and

after implantation with respect to chemical composition

and morphology of the surfaces. After implantation the

biological response was evaluated by counting numbers

of macrophages, giant cells, fibroblasts and other cells

present at the surfaces. The thickness of the fibrous

capsule surrounding the test specimens was measured at

the thickest and thinnest parts. 17 refs.

SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.616597

Item 240Degradation and Stabilization of Materials. Applied

Polymer Symposium proceedings.

Alexandria, 26th-30th Sept.1992, p.231-42. 012

STUDY OF SOME PROPERTIES OF ALGINATEAND SILICONE RUBBER BASE IMPRESSIONSAFTER IMMERSION DISINFECTIONTaymour N M; El-Shabrawi

Alexandria,University

Edited by: Kandil S H

(Alexandria,University)

Applied Polymer Symposium 55

Dental impressions of an engraved metal die were made

with alginate and silicone rubber base impression

materials. After separation from the metal die, all

impressions were soaked (before pouring with Type IV

gypsum) into a variety of test disinfectants via a 30-min

immersion time. Following immersion disinfection, the

linear dimensions of each stone cast (both intra-arch and

cross-arch dimensions) were measured. Surface hardness

characteristics of all the resultant casts were also

examined. Analysis of the results showed that all the

broad-spectrum disinfectant agents used offered effective

antimicrobial activity without distorting the impressions.

There was no significant linear dimensional change or

any alteration in the surface hardness characteristics of

all the examined stone casts. 19 refs.

EGYPT

Accession no.611280

Item 241Rubber Technology International

1996, p.109-11

PLATINUM CURED SILICONE COMPOUNDSSullivan G

Dow Corning STI

Recent advances in platinum-catalysed silicone

compounds have produced high performance liquid

silicone rubber materials and rapid curing high

consistency rubber formulations. Both are helping

moulders to reduce fabricating costs and increase

processing speeds over conventional peroxide-cured

silicones. This comprehensive article supplies full details.

USA

Accession no.610806


26, No.5, 7th Oct.1996, p.28

ACTIVISTS ASK FDA TO RETHINK IMPLANTBANMoore M

Two members of Congress are reported to have joined

anti-cancer activists in Washington to call on the Food

and Drug Administration to reconsider its moratorium on



silicone gel breast implant use. A petition calls on the

agency to ease restrictions on silicone implants for breast

cancer patients. It relies on the body of sound scientific

evidence that has been produced since the FDA

commissioner severely limited access to these medical

devices four years ago. This evidence strongly suggests

that there is no causal link between silicone-gel implants

and systemic connective tissue diseases or classic

autoimmune symptoms. Silicone breast implants are

currently available only to patients involved in the FDA

clinical trials to monitor the effects of silicone on women.

Details are given.

USA

Accession no.610082


4, No.9, Sept.1996, p.98/104

FOR LSR, HIGH TECHNOLOGY OUTWITSLOW LABOUR COSTSNeilley R

An Austrian company, Starlim GmbH, has won back from

Asia a keyboard contact mat production job, which was

sourced from Asia due to its low labour costs, since the

compression moulded natural rubber mats required post-

mould trimming and involved much handling. Starlim

uses liquid injection moulding of silicone rubber,

sophisticated moulds, and an injection system to produce

the product at half the cost, whilst improving performance

and durability. Details are given of the production by

Starlim, and the redesign of the mat into a pattern of domes

and connecting strips.

STARLIM GMBHASIA; AUSTRIA; WESTERN EUROPE

Accession no.608155

Item 244Advanced Packaging

5, No.5, Sept/Oct.1996, p.30/2

FINDING A CUREVanwert B; Wilson S W; Hanlon A

Dow Corning Corp.

Electronic applications are reported to demand that

adhesive products possess a number of properties in

addition to good adhesion and compatibility with substrate

materials. Most adhesives used in a production

environment are heat cured, both for processing speed

and ultimate physical properties. Flexibility is also

necessary to prevent damage during temperature cycling,

even if the assemblies are not subjected to extreme heat

or cold. Finally, the ability to maintain physical properties

in the presence of moisture, contaminants and varying

temperatures is imperative for many applications. Aspects

of silicone adhesives in electronic applications described

include application requirements, physical properties,

processing requirements, cure mechanisms and testing.

Accession no.607356

Item 245Chemistry of Materials

8, No.8, Aug.1996, p.1735-8

NANOCOMPOSITES PREPARED BYTHREADING POLYMER CHAINS THROUGHZEOLITES, MESOPOROUS SILICA, OR SILICANANOTUBESFrisch H L; Mark J E

New York,State University; Cincinnati,University

A brief review is given of preliminary attempts to prepare

nanocomposites in which PDMS chains thread through

the cavities or channels of several types of inorganic

materials. Emphasis is given to the use of zeolites, a

mesoporous hexagonal form of silica, and silica

nanotubes. The effects of the constraining geometry on

the properties of the chains, particularly their Tg were

determined. 91 refs.

USA

Accession no.603765

Item 246Antec ’96. Vol.I. Conference Proceedings.

Indianapolis, 5th-10th May 1996, p.381-5. 012

TWIN-SCREW EXTRUSION PROCESSING OFFILLED POLYMERSLawal A; Railkar S; Yaras P; Kalyon D M

Stevens Institute of Technology

(SPE)

Results are presented of an integrated study of the

extrusion behaviour of a viscoplastic polydimethyl

siloxane suspension filled with hollow glass spheres. The

rheological properties of the suspension, including the

Navier wall slip condition, were characterised by multiple

viscometric flows. The pressure and temperature history

in the co-rotating twin-screw extrusion process was

simulated using finite element analysis and compared with

experimental data collected with a well instrumented 50.8

mm twin-screw extruder. The model results agreed well

with the experimental data and provided a detailed

understanding of the thermomechanical history

experienced by the suspension during twin-screw

extrusion. 43 refs.

USA

Accession no.602941


17, No.16, 1996, p.1627-30

DYNAMIC MECHANICAL THERMALANALYSIS OF DENTURE SOFT LININGMATERIALSWaters M; Jagger R; Williams K; Jerolimov V

Wales,University; Zagreb,University



Details are given of the characterisation of the deformation

properties of a range of long-term denture soft lining

materials using dynamic mechanical thermal analysis.

Specimens were subjected to sinusoidal shear deformation

to simulate the type and rate of deformation soft lining

materials would experience clinically. Data are given for

various acrylic resins and silicone elastomers. 7 refs.

CROATIA; EUROPEAN COMMUNITY; EUROPEAN UNION;

UK; WESTERN EUROPE

Accession no.602615


39, No.5, May 1995, p.47-8

Italian

LIQUID SILICONE RUBBERS FOR INJECTIONMOULDING

Processing conditions and machinery used in the injection

moulding of liquid silicone rubbers are described. Types of

products which can be manufactured by this process are

examined, and causes of moulding faults are briefly reviewed.

GE SILICONESUSA

Accession no.598421


39, No.5, May 1995, p.45-6

Italian

MARGUM 1715U: A SILICONE RUBBER FORWIRE AND CABLE EXTRUSIONCabrini G

Dow Corning STI

Data are presented for the mechanical and electrical

properties and flammability characteristics of Margum

1715U, a silicone rubber compound developed by Dow

Corning STI for applications in wire and cable extrusion.


WESTERN EUROPE

Accession no.598420


39, No.5, May 1995, p.42-5

Italian

PROPERTIES AND SELECTION OF SILICONERUBBERSSteinberger H

Bayer AG

The structure, properties, vulcanisation and processing of

silicone rubbers are examined. Properties and applications

of Silopren silicone rubbers produced by Bayer are described.


WESTERN EUROPE

Accession no.598419


PROCESS FOR PRODUCING A FORMEDSILICONE FOAM BY INJECTION MOULDINGGiesen F J

Fuller H.B.,Licensing & Financing Inc.

To manufacture high quality, fine pored silicone foam

parts by the injection moulding process, two reaction

components A and B are used. They both contain a silicone

polymer and fumed silica. The component A also contains

a complexed organo-platinum catalyst and a small portion

of water, whereas the other component B contains as a

crosslinker polydimethyl hydrogen siloxane. At least one

of the two components A and B of the mixture is

pressurised with a gas, preferably air or nitrogen, in a

pressure container so that the gas is dissolved into the

component(s). The components A and B are mixed in the

pressure process, injected into an injection mould, and

heated so that the foaming process forms the silicone foam

part.

USA

Accession no.596618


61, No.4, 25th July, 1996, p.703-13

COLLAPSIBLE-TUBE PULSATIONGENERATOR FOR CROSSFLOWMICROFILTRATION: FATIGUE TESTING OFSILICONE RUBBER TUBESHadzismajlovic D E; Bertram C D

New South Wales,University

Fatigue tests were performed on 18 silicone rubber tubes

operating as the active element of a crossflow pulsation

generator. 22 refs.

AUSTRALIA

Accession no.596012

Item 253Analyst

121, No.6, June 1996, p.53R-63R

SILICONES AND THEIR DETERMINATION INBIOLOGICAL MATRICES: A REVIEWCavic-Vlasak B A; Thompson M; Smith D C

Toronto,University

A review of the literature on silicones and their

determination in biological matrices is presented. The

following topics are covered: properties and applications

of silicones; biochemistry of elemental silicon and

silicones; general approach to the determination of trace

amounts of silicones in biological materials; survey of

methods used for non-specific and silicon-specific

microstructural determination of silicones in tissues

(microanalysis); silicone-specific (elemental) techniques

for the detection of silicones in biological materials;



survey of silicone-specific techniques (IR, FTIR, Raman,

NMR spectroscopies, gas chromatography(GC) and GC-

mass spectrometry methods); and problem of speciation

of silicon and identification of silicone biotransformation

products in biological samples. 124 refs.

CANADA

Accession no.595316


MICROWAVE-HEATABLE EXERCISE PUTTYMicallef A M; Gibbon R M


A microwaveable exercise putty includes a borosiloxane

or stannosiloxane reaction product. The resulting reaction

product is mixed with a second polysiloxane, an internal

lubricant such as a monounsaturated fatty acid, and a

particulate material which creates heating upon subjection

to microwave energy. Precipitated silica is a particularly

preferred particulate material. The exercise putty may be

manipulated by patients, and at the same time is capable

of delivering heat to the body part undergoing the

manipulation.

USA

Accession no.594354

Item 255IRSG 36th International Rubber Forum 1995: Factors

Affecting the Development of the Rubber Industry in

the Pacific Rim. Conference Proceedings.

Tokyo, 27th Feb.-3rd March 1995, p.143-158

SILICONE ELASTOMERS: THEIR PRESENTAPPLICATIONS AND FUTURE POTENTIALTanimura M


This paper discusses silicone markets, major suppliers,

silicone as an elastomer, silicone rubber applications,

trends in technology and the future outlook. In the US,

the automotive sector is the most important for silicone

rubbers and accounts for 40% of the total market. In Japan,

55% of the total market is accounted for by the electrical/

electronic sector. In the Pacific region, excluding Japan,

68% goes into electrical/electronic manufacturing. New

and emerging applications include automotive airbag

coating, electrical insulators and copier/printer wells.

JAPAN

Accession no.593330


METHOD OF REDUCING HOTHYDROCARBON OIL SWELL OF FILLEDSILICONE SEALANT GASKETSLower L D

Dow Corning Corp.

The gaskets are made from a room temperature

vulcanisable silicone sealant composition containing a

hydroxyl endblocked polydimethylsiloxane, calcium

carbonate or a combination of calcium carbonate and

reinforcing silica filler, a specifically selected

ketoximosilane crosslinker combination, such as

vinyltriketoximosilane and methyltriketoximosilane and

a catalyst. They cure rapidly enough to be used on an

automated production line for formed-in-place gaskets.

USA

Accession no.592982

Item 257British Engel Elast Symposium 1995. Symposium

Proceedings.

Warwick, 21st-22nd June 1995, paper 6, pp.16. 831

LIQUID SILICONE RUBBER - PROCESSING,APPLICATIONS AND DEVELOPMENTSNaumann T

Bayer AG

(Engel Vertriebsges mbH)

This paper presents information in some detail on

processing properties and injection moulding applications

of Silopren LSR liquid silicone rubber from Bayer.

Applications listed include electronics, electrical

appliances, automotive products, medical and textile

applications. Newly developed Silopren LSR products,

mould technology and product design are outlined.


WESTERN EUROPE

Accession no.590902

Item 258Polymer Science Series A

38, No.3, March 1996, p.225-31

THERMALLY STABLE ELASTOMERS: INRETROSPECT OF TWO DECADESSokolov S V; Kolokol’tseva I G

Russia,State Research Institute of Synthetic Rubber

State-of-the-art advances that marked the past two decades

in the synthesis and application of thermally stable

siloxane and fluorocarbon elastomers are reviewed. The

main trend consists in changing the priorities from

aerospace applications to automotive and other consumer

goods applications, which determine the new

requirements for the properties of thermally stable

elastomers. 12 refs.

RUSSIA

Accession no.590686


25, No.18, 25th March 1996, p.15

STUDY STIRS BREAST IMPLANTCONTROVERSY



Moore M

It is reported that pro- and anti-breast implant forces are

drawing opposite conclusions from a new epidemiology

study, the results of which were recently published by

researchers at the Harvard University-affiliated Brigham

& Women’s Hospital in Boston. Former silicone implant

manufacturers claim that the study shows that there is no

major risk of disease among women with breast implants.

Opponents of silicone gel breast implants, however, say

that the report invalidates their position. Details are given.

HARVARD UNIVERSITY; BOSTON,BRIGHAM &

WOMEN’S HOSPITALUSA

Accession no.589896


LIQUID SILICONE RUBBER INJECTIONMOULDING MACHINEGrenda D

Whitaker Corp.

A distribution member for the above machine comprises

a channel distribution network for feeding liquid silicone

rubber to a mould die. The silicone rubber is vulcanised

by heating the mould die to around 120C and heat must

be prevented from flowing into feed pipes and nozzles of

the distribution network to ensure that the injection fluiddoes not vulcanise within the feed channels. Plastic heat

insulating feed pipes and nozzles are provided to prevent

overheating of the fluid in the feed channel. The liquid

silicone rubber does not bond to these pipes and nozzles.

The feed pipes can be provided with a reflective outer

surface and separated from plate members by an air gap

to further reduce heat transfer. Advantages of the machine

are reduction in machine cost, easy and cheap replacement

of nozzles and feed pipes and increased reliability.

USA

Accession no.589497

Item 261IRC ’95 Kobe International Rubber Conference.


Kobe, 23rd-27th Oct.1995, p.91-4. 012

ADHESION OF ADDITION CURE SILICONESTO THERMOPLASTICFujiki H; Shudo S


(Japan,Society of Rubber Industry)

A new addition curing silicone rubber having selective

bonding to polycarbonate, PBTP, etc. without adhering

to the mould (metal) in thermoplastics insert molding and

co-injection moulding is described.

JAPAN

Accession no.586128

Item 262Medical Device Technology

7, No.2, March 1996, p.22/8

PURCHASING SILICONEPryce T

SF Medical Ltd.

Differences in medical grade and food contact grade

silicone polymers are discussed with reference to CE

marking. Medical device manufacturers need to be able

to document that they employ the correct materials and

components for a particular application, and to

demonstrate that their suppliers possess the necessary

product range, technical expertise and quality procedures

necessary to assure product integrity. An explanation is

offered of the inspection and testing terms relating to

material specification and testing of silicone polymers. 3

refs.


WESTERN EUROPE

Accession no.584577


68, No.462, Dec.1994, p.568-71

Spanish

LIQUID SILICONE RUBBER: A HIGHPERFORMANCE MATERIAL OF THE FUTURESchulze M

Bayer AG

The processing and applications of Bayer’s Silopren LSR

liquid silicone rubbers are examined. The environmental

advantages of these materials and quality control

procedures used in their manufacture are described.


WESTERN EUROPE

Accession no.583103

Item 264Trends in Polymer Science

4, No.2, Feb.1996, p.52-9

SILICONE HYDROGELS FOR CONTACT LENSAPPLICATIONKuenzler J F

Bausch & Lomb Inc.

The synthetic and formulation approaches that have been

pursued in the design of silicone hydrogels for use in

extended wear contact lenses are reviewed. The synthesis

of hydrophilic block and graft siloxanes and the use of

these hydrophilic silicones in the preparation of hydrogel

formulations are shown to have led to the development

of transparent, wettable and low-modulus materials

possessing extremely high levels of oxygen permeability.

23 refs.

USA

Accession no.582511



Item 265Medical Plastics Industry at the Dawn of the 21st

Century. Retec proceedings.

Rosemont, Il., 25th-26th Oct. 1994, p.133-68 6S

DESIGN OF AN INJECTION MOULDEDSTRUCTURAL SPINE SUBASSEMBLY FORINTRACOCHLEAR STIMULATINGELECTRODES: THE BASIS OF LOW COSTAUTOMATED ASSEMBLYBruszewski W; Rebscher S; Heilmann M; Merzenich M

California,University

(SPE; SPI)

Details are given of the design and manufacture of a

multichannel intracochlear stimulating electrode that can

be assembled by electronic pick and place robots. A

subassembly incorporating stimulating contacts and a 16-

channel conductor array was injection moulded from

silicone rubber. Other polymers analysed were polyether

imide, PP, polysulphone, and polyimide. 15 refs.

USA

Accession no.582186


30, No.3, March 1996, p.305-12

PILLARED-SURFACE MICROSTRUCTURE ANDSOFT-TISSUE IMPLANTS: EFFECT OFIMPLANT SITE AND FIXATIONPicha G J; Drake R F

Baxter Healthcare Corp.

Details are given of the effect of microtissue anatomy

and silicone rubber implant site on fibrosis and blood

vessel approximation. The effect of implant fixation using

sutures was also examined. 5 refs.

USA

Accession no.582162

Item 267Macromolecular Chemistry & Physics

197, No.2, Feb.1996, p.677-86

NOVEL SILICONES FOR TRANSDERMALTHERAPEUTIC SYSTEM. VI. PREPARATIONOF OLIGODIMETHYLSILOXANECONTAINING PYRROLIDONE MOIETY AS ATERMINAL GROUP AND ITS ENHANCINGEFFECT ON TRANSDERMAL DRUGPENETRATIONAoyagi T; Tadenuma R; Nagase Y

Sagami Chemical Research Center

Oligodimethylsiloxanes containing a pyrrolidone

moiety at one chain end were prepared to develop a

silicone-based transdermal penetration enhancer. The

enhancing activity of drug penetration was evaluated

by in vitro experiments using a two-chamber diffusion

cell. Indomethacin and antipyrine were used as model

drugs. 15 refs.

JAPAN

Accession no.580996


30, No.2, Feb.1996, p.245-50

CONTRIBUTION OF VASCULAR CATHETERMATERIAL TO THE PATHOGENESIS OFINFECTION: DEPLETION OF COMPLEMENTBY SILICONE ELASTOMER IN VITROMarosok R; Washburn R; Indorf A; Solomon D;

Sherertz R

Lentini Medical Center; Wake Forest,University; Akron

Infectious Diseases Inc.; Becton Dickinson

Pharmaceutical Systems

A functional complement opsonisation assay and

radioimmunoassays were used to compare the relative

abilities of silicone, PU and PVC to activate complement.

Serum incubated in silicone catheters for 24 h had less

than 30% of the opsonising ability of fresh serum while

78% or more of the opsonising ability remained with

serum incubated in PU or PVC catheters. Measurement

of C3a des Arg, C4a des Arg, C5a des Arg and SC5b-9

demonstrated that the loss of opsonising ability was due

to 10-fold greater alternate pathway complement

activation by silicone than by PU or PVC. This finding

suggested that excessive complement activation by

silicone could explain the greater inflammation seen

around silicone catheters in vivo and might also play a

role in silicone’s creating a greater risk of infection. 47

refs.

USA

Accession no.580659

Item 269148th ACS Rubber Division Meeting. Fall 1995.


Cleveland, Oh., 17th-20th Oct.1995, Paper 86, pp.12.

012

ADVANCES IN SILICONE RUBBER ENGINEGASKET SEALINGFiedler L D; Hebda T J; Kucinski E M; Lee M H;

Zawadzke J K

Dow Corning Corp.; Dow Corning STI

(ACS,Rubber Div.)

An account is given of tests undertaken by Dow Corning

in the development of silicone rubber compounds for use

in automotive engine gaskets, with particular reference

to the optimisation of compression set resistance,

compression stress relaxation properties and performance

in hot oils.

USA

Accession no.580268



Item 270Polymat ’94 - Polymer Technologies for Electronics.


London, 19th-22nd Sept.1994, p.369-74. 6E

RECENT ADVANCES IN ENCAPSULATION OFMICROELECTRONICS: MATERIALS ANDPROCESSESWong C P

AT & T Bell Laboratories

(Institute of Materials)

Recent advances in polymeric materials and integrated

circuit encapsulants have made high reliability very large

scale integration plastics packaging a reality. High

performance silicone gel possesses excellent electrical

and physical properties for integrated circuit protection.

With their intrinsic low modulus and soft gel-like nature,

silicone gels have become very effective encapsulants

for larger, I/O, wire-bonded and flip-chip VLSI chips.

Integrated circuit technological trends are reviewed,

together with integrated circuit encapsulation materials

and processes. Emphasis is placed on the high

performance silicone gel, epoxies and polyimides, their

chemistry and use as VLSI device encapsulants for single

and multi-chip module applications.10 refs.

USA

Accession no.579676

Item 271Medical Device Technology

7, No.1, Jan/Feb.1996, p.16-8

EVALUATING SILICONE TUBINGHibberd S

Silicone Altimex Ltd.

Concerns associated with the use of silicone tubing in

medical pumping operations are addressed. In particular,

the quantity of extractables that are produced during use

is examined in pumping trials which are performed to

determine the life span of two types of silicone tubing;

platinum cured and peroxide cured. 2 refs.


WESTERN EUROPE

Accession no.579590


Aug.1995, p.127

SILICONES AND MOULDS

The advantages of using silicone rubber for moulds is

described.

GE SILICONES


WESTERN EUROPE

Accession no.571210


No.1610, 3rd Nov.1995, p.12

GERMAN MOULDER UPS LSR CONTROL

Woco reports that it is regularly achieving shot weight

standard deviations of less than 0.2% from its Arburg

Allrounder liquid silicone rubber injection moulding

system. In one test, which lasted almost three hours, seal

covers for a car central locking system weighing 5.542g

were produced with a standard deviation of 0.013g. The

Woco machine features Selogica control and a special

15mm screw LSR injection unit. This latter unit is

equipped with a spring-loaded non-return valve which

prevents material from flowing back into the screw,

enabling a high shot weight consistency and a good

surface finish to be achieved even without running a

material cushion.

ARBURG UK LTD.; WOCOEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.568235

Item 274Advanced Materials for Optics & Electronics

5, No.4, July-Aug.1995, p.199-213

COUPLING MONOLAYERS FOR PROTECTIONOF MICROELECTRONIC CIRCUITSFabianowski W; Jaccodine R; Kodnani R; Pearson R;

Smektala P

Lehigh,University

Two polymeric coatings, a silicone gel (Dow Corning

6646) and an epoxy resins (Dexter FP 4402), were glob-

top coated onto representative microelectronic circuits,

AT & T Triple Track Testers(TTTs), and subjected to a

Pressure Cooker Test. Coupling monolayers were self-

assembled on the TTTs prior to encapsulation to improve

the moisture protection capabilities of the coatings.

Leakage current measurements were carried out in order

to evaluate the effect of applied monolayers on the

moisture protection capability. The moisture protection

capability was assessed in short-term and long-term

leakage current measurements. 16-Mercaptohexadecanoic

acid and gamma-aminopropyltriethoxysilane monolayers,

in combination with silicone gel and epoxy resin,

respectively, exhibited very good moisture protection

performance. 29 refs.

DOW CORNING CORP.; DEXTER CORP.; AT & T

BELL LABORATORIESUSA

Accession no.566576


67, No.6, 1994, p.411-20

Japanese

PRESSURE-SENSITIVE CONDUCTIVERUBBERS (ROAD SENSORS)



Kanamori K

Yokohama Rubber Co.Ltd.

The structure and requirements of silicone-based pressure-

sensitive conductive rubbers are described, particularly

for those used in road sensors for vehicle-sorting systems.

7 refs. Articles from this journal can be requested for

translation by subscribers to the Rapra produced


JAPAN

Accession no.565957


FIRE RETARDANT RESIN COMPOSITIONSRomenesko D J

Dow Corning Corp.

A free-flowing silicone polymer powder, which has an

average particle size of 1 to 1000 microns and is prepared

by mixing a polydiorganosiloxane with a silica filler, and

a phosphorus-based fire retardant compound are

uniformly dispersed in an organic resin using conventional

equipment, such as a single screw extruder. The resulting

resin composition shows a significant improvement in fire

retardancy but does not exhibit the severe deterioration

of impact resistance incurred when the resin is modified

with only phosphorus-based fire retardant.

USA

Accession no.564948

Item 277Advanced Materials for Optics & Electronics

4, No.2, March-April 1994, p.95-127

POLYMERIC SILICON-CONTAINING RESISTMATERIALSMiller R D; Wallraff G M

IBM Research Division

A review of silicon-containing bilayer and trilayer

photoresist technology is presented. Multilayer resist

processes of this type are shown to rely on pattern

generation in a thin imaging layer, followed by pattern

transfer to the thick planarising underlayer by oxygen

reactive ion etching. The review concentrates on materials

in which the silicon is an integral part of the polymer and

does not specifically address photoresists where silicon

is incorporated in a post-imaging process step (such as

top-surface-imaging resists). 147 refs.

USA

Accession no.564760


29, No.10, Oct.1995, p.1179-83

BIOMATERIAL-INDUCED DYSFUNCTION INTHE CAPACITY OF RABBIT ALVEOLARMACROPHAGES TO KILL STAPHYLOCOCCUS

EPIDERMIS RP12Giridhar G; Myrvik Q N; Gristina A G

Medical Sciences Research Institute

The effect of PMMA, titanium alloy, and silicone discs

on the capacity of rabbit alveolar macrophages to kill

RP12 strain of Staphylococcus epidermis was studied in-

vitro. 18 refs.

USA

Accession no.564210

Item 279Journal of Applied Biomaterials

6, No.3, Fall 1995, p.153-60

SELF-REPORTED SIGNS AND SYMPTOMS INBREAST IMPLANT PATIENTS WITH NOVELANTIBODIES TO SILICONE SURFACEASSOCIATED ANTIGENS (ANTI-SSAA(X))Kossovsky N; Gornbein J A; Zeidler M; Stassi J; Chun

G; Papasian N; Nguyen R; Ly K; Rajguru S


In a pilot study performed several years ago involving

about 350 women, it was observed that a small

subpopulation of silicone breast implants exhibited

antibodies with binding avidities for synthetic

macromolecular complexes of silicone surface charged

adsorbed antigens. These antibodies were unique to breast

implant patients and were not found in either age matchedhealthy patients or rheumatic diseased patients who did

not have silicone implants. The present study was

undertaken to determine if these antibodies might have

any clinical significance and if the model of silicone

surface associated antigens might help rectify the

discrepancy between the various data pools. 60 refs.

USA

Accession no.562154


29, No.9, Sept. 1995, p.1129-40

AGEING OF SILICONE RUBBERBIOMATERIALS WITH NMRPfleiderer B; Xu P; Ackerman J L; Garrido L

Harvard Medical School; Cincinnati,University

Multinuclear NMR was used to characterise the ageing

process of silicone rubber-based biomaterials after long-

term implantation. The migration of free silicone from

the implants to adjacent tissue was also determined. 35

refs.

USA

Accession no.561605


16, No.15, 1995, p.1193-7

INFLUENCE OF DIMENSIONAL STABILITY OF



IMPRESSION MATERIALS ON THEPROBABILITY OF ACCEPTANCE OF APROSTHETIC RESTORATIONPamenius M; Ohlson N G

Karolinska Institute

The accuracy of rubber impression materials was

evaluated by taking impressions of a steel model, pouring

it with stone and comparing certain measurements

between steel and stone models. It is said that acceptance

is achieved when the difference in measurements is within

permissible limits defined by clinical criteria. Data are

given for silicone polymer and polyether impression

materials. 18 refs.


Accession no.560913


3, No.8, Aug.1995, p.66-7

BOTTOM-LINE BENEFITS OF COLD RUNNERLIMKirkland C

Kipe Molds claims that users of the liquid injection

moulding process should weigh the cost and complexity

of cold runner tooling against the cost of non-recyclable

liquid silicone rubber scrap. Cold runner moulds for liquid

silicone rubber can cost two to three times more thanmoulds for conventional runner systems. The elimination

of waste with a costly raw material is likely to provide a

competitive edge. Details are given.

KIPE MOLDS INC.USA

Accession no.560597

Item 283Rubbercon ’95. Conference Preprints.

Gothenburg, 9th-12th May 1995, Paper D1, pp.5. 012

SYNTHETIC VERSUS NATURAL POLYMERS INTHE BIOLOGICAL ENVIRONMENTYannas I V

Massachusetts,Institute of Technology

(Nordic Council of Rubber Technology)

A comparison is made of interactions occurring

between body tissue and synthetic and natural

biomaterials used in implants. It is shown that implants

based on non-degradable polymers such as silicone

rubber induce the synthesis of a fibrous capsule on their

surface, whereas degradable polymers obviate the

formation of a fibrous capsule. Certain natural

polymers, such as highly porous graft copolymers of

type I collagen and chondroitin sulphate (a

glycosaminoglycan), induce the regeneration of

missing tissue rather than the synthesis of scar tissue.

SCANDINAVIA; SWEDEN; USA; WESTERN EUROPE

Accession no.560441

Item 284Design Engineering

July/Aug.1995, p.13

RHEOLOGICAL FLUIDS GIVE BIRTH TOINTELLIGENT SHOCK ABSORBERS

It is reported that the cars of the future may well have

shock absorbers that adapt automatically to road

conditions. Bayer has already made some progress in this

area by carrying out its first tests on shock absorbers with

electrorheological fluids (ERFS). These low-viscosity

‘intelligent fluids’ become highly viscous upon

application of an electrical field. Details are given of the

company’s Rheobay fluid, which is based on a non-

aqueous dispersion of spherical polymer particles in

Baysilone Fluid M, a silicone liquid.

BAYER AGEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.560165


METHOD FOR FABRICATING FOAM GASKETSAkitomo H; Nozoe T; Shinmi H


A method for fabricating foam gaskets is characterised in

that during the separate transport and subsequent mixing

in an enclosed chamber of the base and curing agent

portions of a two part foamable and curable organosiloxane

composition an inert gas is injected in an amount of 1-50

ml per 100 g of the total curable organosiloxane

composition. The gas is injected into either the base portion,

the curing agent or during or immediately after mixing of

the two portions, and the resultant foamable composition

is then extruded from a nozzle onto the seal region of the

substrate and cured while foaming.

JAPAN

Accession no.557022


29, No.7, July 1995, p.849-56

VISCOELASTIC AND ADHERENCEPROPERTIES OF DENTAL RELININGMATERIALSBuch D; Wehbi D; Roques-Carmes C

ENSMM

The viscoelastic properties of acrylic resin, silicone resin

and EVA copolymer dental relining materials were studied

comparatively. Their behaviours were investigated by in

vitro tests that simulate the masticatory cycle. An attempt

was made to correlate the experimental data to the

viscoelastic energy loss observed when instability of the

prosthetic structure occurs. 19 refs.


WESTERN EUROPE

Accession no.555450




48, No.6, June 1995, p.443-7

UPDATED COMPARISON BETWEEN TOPPERFORMANCE ELASTOMERS INAUTOMOTIVE APPLICATIONSMeyers G

EniChem

Details are given of comparisons between high

performance elastomers used in the automotive industry.

Basic mechanical properties, heat ageing, oil resistance

and low temperature properties are described for NBR,

acrylic rubber, ethylene acrylic rubber, hydrogenated

NBR, chlorosulphonated PE, epichlorohydrin rubber, and

silicone rubber. 5 refs.


WESTERN EUROPE

Accession no.554894


METHOD FOR PREPARING SILICONE MOULDTOOLINGEast D A

Spraying of high viscosity silicone moulding compositions

is described, together with cured silicone moulds or tools

formed by the process that allow for near perfect transfer

of details from a surface to a moulded object.

USA

Accession no.554039


COATING SOLUTION FOR FORMINGTRANSPARENT CONDUCTIVE COATING ANDPROCESS FOR PREPARING SAMEHirai T; Komatsu M; Nakashima A; Abe Y; Iwasaki Y

Catalysts & Chemicals Industry Co.Ltd.

A conductive substrate is described, coated with a transparent

conductive coating prepared by dispersion in water and/or

organic solvent of conductive particles having (a) an average

particle diameter of not more than 500 Angstroms, in which

(b) more than 60 wt.% of particles have a diameter of not

more than 600 Angstroms, (c) not more than 5 wt.% of

particles have a particle diameter of not more than 100

Angstroms and (d) not more than 15 wt.% of particles have

a particle diameter of more than 1000 Angstroms. There is a

matrix comprising a silica polymer having an average degree

of polymerisation of 1,500-10,000. The coatings have

excellent adhesion and surface smoothness and also excellent

durability and transparency. Display devices using the

transparent conductive substrates as the display panel have

excellent resolving power, and give constantly clear and

sharp images.

JAPAN

Accession no.553395


INTEGRATED THERMOPLASTIC RESIN/SILICONE RUBBER ARTICLES AND METHODFOR MAKINGFujiki H; Shudo S


An integrated thermoplastic resin/silicone rubber article

is prepared by modifying a thermoplastic resin with a

silicon-containing compound in monomer or polymer

form, moulding the thermoplastic resin into a shape,

contacting an uncured silicone rubber with the moulded

thermoplastic resin, and curing the silicone rubber at a

temperature below the softening point of the thermoplastic

resin. The article in which the thermoplastic resin is firmly

united with the silicone rubber is useful in electric,

electronic and automotive applications while taking

advantage of the inherent reliability in heat resistance,

weather resistance and electrical properties of the silicone

rubber.

JAPAN

Accession no.552555


212, No.2, May 1995, p.20/59

AEM - EXTENDED AGEINGS IN SELECTIVEAUTOMOTIVE FLUIDSDobel T M; Kotz D A

DuPont Co.

Changes in the automotive industry are increasing the

demands for higher performance seal and gasket materials

in both the engine and transmission. Moulded rubber

gaskets, carrier gaskets and moulded-in-place

technologies have become the preferred sealing systems.

The vast majority of these newer gasket designs are made

from silicone (VMQ) rubber. The use of ethylene acrylic

elastomers (AEM) in powertrain applications has steadily

increased in recent years, mainly because of their good

balance of high and low temperature properties and oil

resistance. This article compares four AEM polymers,

three of them new grades, with VMQ and polyacrylate.

Extended ageing studies in both engine oil and automatic

transmission fluid are used to demonstrate the merits of

AEM polymers over the long term for powertrain gaskets.

2 refs.

USA

Accession no.552488


No.734, Sept.1994, p.68-70

French

SURFACE DEFECTS AND MICROSTRUCTUREOF HEAT CURABLE SILICONE ELASTOMERSVarlet J; Pouchelon A; Bourrain P; Joachim F



Rhone-Poulenc SA

Results are presented of a capillary rheometer study of

the influence of extrusion conditions and rheological

properties on defects occurring on the surface of heat

curable polydimethyl siloxane extrudates. 4 refs.


WESTERN EUROPE

Accession no.552429


68, No.458, Aug.1994, p.173-80

Spanish

DISPERSED ELECTROMAGNETIC SYSTEMS.II. POLYMERS USED IN THEIRMANUFACTURE AND THEIR APPLICATIONSDavidenko N; Orlov D V; Sastre R

Havana,University; Edys; Instituto de Ciencia y

Tecnologia de Polimeros

A survey is made of polymers used in magnetic fluids,

including polysiloxanes and a variety of plastics, and of

a number of uses of these systems, such as hermetic seals,

vibration dampers, lubricants and medical and

pharmaceutical applications. 67 refs.

CUBA; EUROPEAN COMMUNITY; EUROPEAN UNION;

RUSSIA; SPAIN; WESTERN EUROPE

Accession no.552411

Item 294147th Meeting, Spring 1995, Conference Preprints.

Philadelphia, Pa., 2nd-5th May 1995, Paper 57, pp.55.

012

CHARACTERISING RUBBER ELASTICBEHAVIOUR FOR FINITE ELEMENTMODELLINGChouchaoui B; Ulrich E

Gecamex Technologies Inc.

(ACS,Rubber Div.)

Silicone and fluorosilicone rubbers were characterised for

finite element analysis in simple Shore A deformation

modes using as key properties the polynomial and Ogden

strain energy density functions. The influence of material

data on the quality of model representation of automotive

ring gaskets and grommet fasteners was examined. The

predicted force-deflection characteristics satisfactorily

compared to empirical data when proper material models

were selected. Issues such as mesh density, element type

and dimensional tolerances in part geometry were also

studied. 33 refs.

CANADA; USA

Accession no.552390

Item 295147th Meeting, Spring 1995, Conference Preprints.

Philadelphia, Pa., 2nd-5th May 1995, Paper 3, pp.22. 012

USE OF SILICONE RUBBER ON DISCARDINGSABOT PROJECTILESWalker F J

Alliant Techsystems Inc.

(ACS,Rubber Div.)

The application of liquid, high consistency and pumpable

silicone rubbers in gas seals for discarding sabot projectile

assemblies is discussed. An examination is made of the

properties required of such seals, processes used in their

manufacture, and methods for bonding silicone rubber to

steel, aluminium and plastics inserts used in this

application. 7 refs.

USA

Accession no.552346


29, No.5, May 1995, p.583-90

ASSESSMENT OF VIABILITY ANDPROLIFERATION OF IN-VIVO SILICONE-PRIMED LYMPHOCYTES AFTER IN-VITRORE-EXPOSURE TO SILICONECiapetti G; Granchi D; Stea S; Cenni E; Schiavon P;

Giuliani R; Pizzoferrato A

Bologna,Istituti Ortopedici Rizzoli

The functional response of peripheral blood lymphocytes

isolated from 22 patients with silicone gel-filled breastimplants was assessed after in-vitro re-exposure to

silicone. Using cell culture test methods to quantify

proliferation and viability and/or activation of lymphocyte

microcultures, i.e. the uptake of tritiated thymidine and

the reduction of formazan salts, interesting assay data were

obtained. 18 refs.


WESTERN EUROPE

Accession no.551618

Item 297Journal of Biomaterials Science : Polymer Edition

7, No.2, 1995, p.147-57

REVIEW. RHEUMATIC DISORDERS INPATIENTS WITH SILICONE IMPLANTS: ACRITICAL REVIEWBridges A J

Wisconsin,University; Middleton W.S.,Memorial

Veterans Admin.Hospital

More than 1000 patients with rheumatic disorders and

silicone implants have been reported. The clinical features

of patients with scleroderma, inflammatory myositis,

systemic lupus erythematosus and silicone implants are

discussed. The clinical features of the most common

rheumatic disorder associated with silicone implants, the

‘silicone implant associated syndrome’ are introduced.

In addition, other local regional, and neurological

disorders associated with silicone implants are discussed.

This comprehensive clinical review provides the clinician



with information regarding the common symptoms, signs

and laboratory features of rheumatic disorders of patients

with silicone implants. 50 refs.

USA

Accession no.551516


7, No.2, 1995, p.133-45

SILICONE BREAST IMPLANTS ANDAUTOIMMUNITY: CAUSATION, ASSOCIATION,OR MYTH?Brautbar N; Campbell A; Vojdani A

Southern California,University; Texas,University;

Drew,University of Medicine & Science

In-vivo and in-vitro studies, case reports and population

studies show that (i) silicone is immunogenic, (ii) silicone

is biodegradable and transported via the

reticuloendothelial system to distant locations, (iii)

silicone breast implants leak and in turn silicone migrates

outside the breast tissue, (iv) case reports and population

studies document an autoimmune reaction and

immunological dysfunction in patients with silicone breast

implants, (v) these immunological abnormalities and

symptoms are reversible upon removal of the breast

implants (in 50-70% of cases). The criteria to establish

medical causation are defined, and based on those criteria

it is concluded that silicone breast implants cause

immunological disease. 55 refs.

USA

Accession no.551515


7, No.2, 1995, p.115-21

REVIEW. DO SILICONE BREAST IMPLANTSCAUSE AUTOIMMUNE RHEUMATICDISEASES?Smith H R

Case Western Reserve University

A spectrum of illnesses ranging from local symptoms to

systemic disease is seen in some patients with silicone

breast implants. However, it remains to be determined

whether such illnesses in these patients are coincidentally

associated or are secondary to the implants. This article

reviews data relating to this issue. 41 refs.

USA

Accession no.551513


7, No.2, 1995, p.101-13

REVIEW. PHYSICOCHEMICAL ANDIMMUNOLOGICAL BASIS OF SILICONEPATHOPHYSIOLOGY

Kossovsky N; Frieman C J


Silicones, model biomaterials with almost ubiquitous

applications, are the focus of a contentious debate. In this

review, both established physicochemical phenomena and

immunological phenomena are considered, then the human

clinical phenomena that relate directly to them are

considered. Two competing theories of the biological activity

of silicones are explored, and weaknesses in the various

arguments that silicone is inert are discussed. 91 refs.

USA

Accession no.551512

Item 301Journal of Materials Science.Materials in Medicine

6, No.3, March 1995, p.177-80

SILICONE ELASTOMERS: STUDY OF THEIRMESH SIZE BY THERMAL ANALYSISMoreau J C; Madelmont G; Leclerc B; Mazan J;

Couarraze G

Paris-Sud,Universite

Silicone elastomers are often used as a base for controlled-

release systems for drugs and the modulation of drug

diffusion by varying the mesh size of a silicone elastomer

network has previously been studied. In this work, the

effect of vulcanisation conditions and chemical

modifications on the network mesh size was investigatedby thermal analysis and measurement of swelling ratio.

The influence of these parameters on the diffusion of

model drugs was also studied. 15 refs.


WESTERN EUROPE

Accession no.549399


MONITOR PUTTYGibbon R


An apparatus for providing manipulative physical therapy

includes a first mass of a putty including a reaction product

of siloxane with a boron- or tin-containing compound and

a polysiloxane. At least one additional mass of the putty

is provided to the patient, the mass adaptable to be

manually combined by the patient with the first mass until

a uniform colour is achieved. The apparatus provides a

means by which the progress of manipulative physical

therapy may be monitored, as a uniform colour in the

combined mass will be achieved only after extensive

manipulation.

USA

Accession no.545000




April 1994, p.122-3

LIQUID SILICONE RUBBER FOR HIGHPERFORMANCESchulze M

Bayer AG

Applications of liquid silicone rubbers in injection

moulded components and heat resistant protective

clothing are described. Recycling and other environmental

aspects of these materials are also discussed.


WESTERN EUROPE

Accession no.544318


No.729, Feb.1994, p.64-7

French

RUBBER TEATS: MATERIALSDEVELOPMENTS AND REGULATIONSCardinet C; Niepel H

Hutchinson SA; Mapa GmbH

Materials used in teats for baby feeding bottles, including

NR, silicone rubber and styrene-butadiene block copolymer

thermoplastic elastomers are examined, and processes and

additives used in the manufacture of teats are described. A

survey is made of regulations in a number of countries

covering the toxicological characteristics of such materials,

and of test methods used to determine the migration and

extractability of additives and the presence of specific

compounds, with particular reference to nitrosamines. 5 refs.


GERMANY; WESTERN EUROPE; WORLD

Accession no.544277

Item 305Reinforced Plastics

39, No.3, March 1995, p.16

FAST AND EASY PROTOTYPING OF COMPLEXPARTS

Protomix from Camattini is an easy, cheap and fast tool for

rapid prototyping. The system consists of a vacuum chamber

with a four-way pneumatic injection system controlled by a

pneumatic gun for product mixing and for injection into the

mould, a 24 or 36 element static mixer, twin cartridges

containing the different Protomix PU products designed to

ensure consistent prototyping, and a transparent silicone

rubber which has a high degree of dimensional stability and

low shrinkage for mould production.

CAMATTINI SPAEUROPEAN COMMUNITY; EUROPEAN UNION; ITALY;

WESTERN EUROPE

Accession no.544136

Item 306Urethane Plastics and Products

25, No.1, Jan.1995, p.1-2

ROGERS CORPORATION SPOTLIGHTS HIGHPERFORMANCE ELASTOMER MATERIALSAND COMPONENTS

Properties and applications of two high performance

elastomer materials from Rogers Corp. are discussed in

some detail. Poron cellular urethane and silicone materials

are reported to be used for products such as gaskets for

disc drives, vibration isolators in machinery, and airbag

detonator protection devices. The company’s Endur range

of elastomeric materials are said to be used in applications

such as components for document handling in office

equipment and extended component life is now reported

to be offered by the new polyisoprene version of Endur

products.

ROGERS CORP.,PORON MATERIALS DIV.USA

Accession no.542377

Item 307Antec ’94. Conference Proceedings.

San Francisco, Ca., 1st-5th May 1994, Vol.I, p.894-6.

012

DETERMINING MOULD FILLING ANALYSISACCURACY FOR THERMOSET MATERIALMutkus E A

Pennsylvania,State University

(SPE)

Pressures predicted by mould filling analysis software

for the moulding of silicone rubber were compared with

results from the actual moulding process. The predictions

were within 10% of the actual process pressures.

USA

Accession no.541223


29, No.1, Jan.1995, p.59-63

KINETIC STUDY OF RELEASE OF SILICONCOMPOUNDS FROM POLYSILOXANE TISSUEEXPANDERSRaimondi M L; Sassara C; Bellobono I R; Matturri L

Milan,University

The release behaviour of commercial tissue expanders

was examined by the determination of the chemical nature

and its modification after in vivo use by ESCA, and a

kinetic examination of silicon compounds released by the

biomaterial in physiological saline. The correlation of

kinetic and physicochemical tests with the in vivo

behaviour is discussed. 9 refs.


WESTERN EUROPE

Accession no.538596





012

DEVOLATILISATION OF PDMS GUMS: APERFORMANCE COMPARISON OF CO- ANDCOUNTER-ROTATING TWIN-SCREWEXTRUDERSPowell K G

General Electric Co.,Corporate R & D

(SPE)

A study was made of the performance of a co-rotating

twin-screw extruder and a non-intermeshing counter-

rotating twin-screw extruder in the devolatilisation of

polydimethyl siloxane gums. Hydrodynamic differences

between the extruders were reflected in their

devolatilisation performance as a function of operating

parameters. The concept of normalised residuals based

on Latinen’s wiped film model was a useful method for

classifying devolatilisation problems and simplifying

process optimisation. 11 refs.

USA

Accession no.537964



012

USE OF DIE MODELLING TO IMPROVE THEMANUFACTURING PROCESS FOR EXTRUDEDSILICONE RUBBERReese C; Marchal T; Marchal J M

Dow Corning Corp.; Polyflow SA

(SPE)

Flow analysis software was used to develop a die and

process parameters for the extrusion of complex three-

hole silicone rubber tubing. The resulting modified die

mandrel gave satisfactory match-up of extrudate shape

to the desired shape, increased product quality and

production rate and reduced set-up time. 3 refs.

BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION;

USA; WESTERN EUROPE

Accession no.537941

Item 311Plastiques Flash

No.273, July/Aug.1994, p.40-2

French

LIQUID SILICONES TODAY

The properties, processing and applications of liquid

silicone rubbers are reviewed.

BAYER AG; DOW CORNING CORP.; WACKER-

CHEMIE GMBH; RHONE-POULENC SA;

BEUCHAT G.; M2SEUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE;

GERMANY; USA; WESTERN EUROPE

Accession no.537919


68, No.457, July 1994, p.22-9

Spanish

SYNTHESIS AND STUDY OF THE OPTICALAND ELECTRONIC PROPERTIES OFPOLYSILANES. II.Peinado C; Catalina F; Schnabel W

Instituto de Ciencia y Tecnologia de Polimeros; Hahn-

Meitner-Institut Berlin GmbH

An examination is made of the electronic transport and

non-linear optical properties of polysilanes. Uses of these

polymers as photoinitiators in polymerisation processes

and precursors for silicon carbide and in microlithography,

charge transport, photoconduction and non-linear optical

applications are described. 26 refs. (Part I: Ibid., 67,

No.456, June 1994, p.567-76).


SPAIN; WESTERN EUROPE

Accession no.537904


38, Nos.7/8, July/Aug.1994, p.42-3

Italian

SILICONE RUBBERS FOR THE TREATMENTOF FABRICSMuller J

Wacker-Chemie GmbH

Applications of silicone rubbers in the coating of fabrics

for use in cable insulation, conveyor belting, protective

clothing and automotive air bags are examined. The

Elastosil range of silicone rubbers produced by Wacker-

Chemie is briefly described.

SILMIX SPA


ITALY; WESTERN EUROPE

Accession no.537903

Item 314Polymer Degradation and Stability

46, No.2, 1994, p.241-6

STABILITY OF FIVE PLASTICS USED INMEDICAL DEVICES TO OXIDATIONPRODUCED BY COPPER OR IRON IONS ANDREDUCING AGENTSSagripanti J-L; Hughes-Dillon M K

US,Food & Drug Administration

Polyurethane, silicone rubber, polyamide, PVC, and PE

were exposed to metal-based formulations containing

copper ions or iron ions. Oxidation effects are discussed.

17 refs.

USA

Accession no.537488




28, No.12, Dec.1994, p.1433-8

SPLENIC RESPONSE TO SILICON DRAINMATERIAL FOLLOWING INTRAPERITONEALIMPLANTATIONGuo W; Willen R; Liu X; Odelius R; Carlen B

Lund,University

Silicone rubber drain fragments were implanted

intraperitoneally to study the splenic response. Four days

after implantation samples of spleen and implanted rubber

fragments were retrieved and studied by SEM and energy

dispersive X-ray microanalysis. 7 refs.


Accession no.536611


5, No.9, Sept.1994, p.473-8

CYCLIC POLYMERS: PAST, PRESENT ANDFUTURESemlyen J A; Wood B R; Hodge P

York,University; Manchester,University

Methods for characterising cyclic polymers are illustrated

by reference first to dilute solution methods for cyclic

polydimethylsiloxane (PDMS) and then to the entrapment

of cyclic polymers in networks. Preparative routes to

cyclic polymers are reviewed, including ring-chain

equilibration reactions, coupling and condensation

reactions and new methods using polymer-supported

reagents. Some of the properties of PDMS are discussed,

including differences between ring and chain polymer

properties such as their melt viscosities and Tgs. Methods

for preparing the first polymeric catenanes are described,

using polymer-supported reagents. Further directions for

cyclic polymer chemistry are indicated, including

topological polymer chemistry. 43 refs.


WESTERN EUROPE

Accession no.535233

Item 317Journal of Advanced Materials

26, No.1, Oct.1994, p.2-8

MOULDING OF COMPLEX COMPOSITE PARTSUTILISING MODIFIED SILICONE RUBBERTOOLINGWeiser E S; Baucom R M

Georgia,Institute of Technology; US,NASA,Langley

Research Center

Cast silicone rubber was utilised as a tooling aid to apply

pressure to complex composite parts during cure.

Emphasis is given to the governing formula for rubber

expansion and innovative methodology for precise control

of the expansion rate. 6 refs.

USA

Accession no.533922

Item 318Chemistry & Industry

No.17, 5th Sept.1994, p.668

FIRST FOR RAMAN SPECTROSCOPY

The US Armed Forces Institute of Pathology (AFIP)

claims to be the first to use Raman spectroscopy to identify

silicone and other foreign materials in breast tissue. The

article supplies details of a Raman microprobe which

provides a non-destructive technique for examining tissue

on a molecular level. The article includes brief details of

three different types of breast implants analysed using

Raman spectroscopy.

US,FOOD & DRUG ADMINISTRATION;

US,ARMED FORCES INSTITUTE OF PATHOLOGYUSA

Accession no.533709


No.1560, 4th Nov.1994, p.7

RUBBER FLIES SKY HIGH

RE Components has developed a new silicone rubber

compound for cable support bushes for the new V2500

turbofan aircraft engine. The bushes hold wiring in place

in harnesses positioned from near the centre of the engine

to the intake fan. The components had to meet a

specification set by the National Society of British

Aerospace Companies for tolerance of extremes of

temperature. Northern Rubber and British Aerospace

have cooperated to produce an improved thermally

insulated air ducting system for Eurofighter 2000

aeroplanes. The silicone rubber hose system helps keep

equipment cooling air and cockpit air conditioning air

at the right temperature. The insulation material is a

sound-absorbing, flame-retardant PU foam with a tough

film coating.

RE COMPONENTS LTD.; NORTHERN RUBBER

CO.LTD.EUROPEAN COMMUNITY; EUROPEAN UNION; UK;

WESTERN EUROPE

Accession no.533621

Item 320Kunststoff Journal

28, No.3, June 1994, p.44

German

RAPID PROTOTYPES

The MCP vacuum casting method is an effective and

relatively cheap way of producing plastic prototypes and

small batches. A casting mould is made of silicon and



casting resin added in a vacuum casting machine and then

cured in a heating chamber.

HEK GMBHEUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY;

WESTERN EUROPE

Accession no.532992

Item 321Plastverarbeiter

45, No.10, Oct.1994, p.26

German

IN-SITU SEALS FOR ENGINE CONSTRUCTION

Using a two-component metering unit, it is possible to

extrude silicon seals directly onto components, e.g. rocker

arm covers, for automobile engine construction.


WESTERN EUROPE

Accession no.532968


24, No.4, 19th Sept.1994, p.6

IMPLANT MAKERS OK 4.25 US BILLIONDOLLAR SETTLEMENTMoore M

The lawsuits taken out against manufacturers of silicone

gel breast implants concern over 90,000 women who have

entered a pact which promises them reimbursement of

between 105,000 and 1.4 million US dollars each over

the next 30 years. Dow Corning and Bristol-Meyers

Squibb Co. affirmed their commitment to the agreement

and the deadline date of 9th September for withdrawal

from the agreement, passed without a defendant company

giving official notice of withdrawal, it is reported.

DOW CORNING CORP.; BRISTOL-MEYERS

SQUIBB CO.USA

Accession no.531787


24, No.3, 12th Sept.1994, p.3

LAWSUITS CLAIM NORPLANT DIFFICULT TOREMOVEMoore M

According to the lawsuit filed recently against Wyeth-

Ayerst Laboratories, their product, a contraceptive system

of implanted capsules tradenamed Norplant, cannot be

removed without extreme pain and permanent scarring

in some cases. The article supplies brief details of the

capsules, made from a patented siloxane polymer, and

the lawsuit.

WYETH-AYERST LABORATORIESUSA

Accession no.531296

Item 324Philadelphia, Pa, 1993. 1/11/93. 6J22

ASTM C 1115-. SPECIFICATION FOR DENSEELASTOMERIC SILICONE RUBBER GASKETSAND ACCESSORIESAmerican Society for Testing & Materials

ASTM C 1115-

Details are given of elastomeric silicone rubber for gaskets

and accessories for use in glazing and sealing applications.

Photocopies and loans of this document are not available

from Rapra. It may be purchased from BSI. Please contact

Rapra for further details.

USA

Accession no.530179


New Orleans, La., 9th-13th May 1993, Vol.III, p.2988-

90. 012

NEW ARTIFICIAL SKIN FACE MASK FORMEASUREMENT OF LACERATIONPOTENTIALMcKinney R; Moody D

Triangle Research & Development Corp.

(SPE)

An account is given of the development of an artificial

skin face mask for dummies used in the measurement offacial laceration potential in trauma and injury research

and automotive component testing. Masks were injection

moulded in PU and silicone polymer compounds, and tests

indicated that a modified two-component silicone had the

best potential for this application. Experiments showed

that such masks could provide approximately the same

laceration index score as double-layer chamois whilst

minimising changes in the dynamic impact response of

the dummy. 7 refs.

APM INC.; BIRMINGHAM,UNIVERSITY;

RENAULT SAEUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; UK;

USA; WESTERN EUROPE

Accession no.528840


New Orleans, La., 9th-13th May 1993, Vol.III, p.2280-

7. 012

PRECISION MOULDING WITH THETIEBARLESS INJECTION MOULDINGMACHINEStrohmaier F

Engel Canada Inc.

(SPE)

Technical features and advantages of tiebarless injection

moulding machines are described, and reference is made

to their use in the flashless moulding of liquid silicone

rubber parts.



CANADA; USA

Accession no.524607


38, No.4, 1994, p.26-7

German

SEALS EXTRUDED NOT INSERTED

The 2K machine extrudes a silicone-based sealing

material directly where required, instead of an O-ring

being inserted by hand. Measuring and extruding takes a

total of 3 seconds. 300,000 engine gear casings have been

sealed in this way for Peugeot with a failure rate of zero.

Technical details of the robot are given.

PEUGEOT SAEUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE;

WESTERN EUROPE

Accession no.522700


21, No.4, 1994, p.T/26-37

SYNTHESIS OF SILICONE POLYMERSInoue H

Methods of synthesising silicone polymers with

polysiloxane chains are reviewed in detail, particularly

hydrolytic condensation of chlorosilanes, ring-opening

polymerisation of cyclic siloxanes, synthesis of silicones

by step-growth reaction (condensation), synthesis of

telechelic silicone oligomers by equilibrium

polymerisation, synthesis of modified silicones by

addition reaction, crosslinking of silicones, and the

synthesis of silicone modified polymers with siloxane

polymer chains or side chains. 112 refs. Translation of

Nippon Gomu Kyokaishi, No.9, 1993, p.660

JAPAN

Accession no.522631

Item 329European Plastics News

21, No.7, July/Aug.1994, p.20

PROTECTING ELECTRONIC CHIPSGuyot H

Most of the discrete semiconductors and integrated

circuits in use today are based on silicon and rely on some

form of resin encapsulation to ensure reliable operation

in real-world environmental conditions. Epoxy

compounds dominate with silicones also being used in

considerable volumes. Transfer moulding dominates the

encapsulation business, with multi-plunger moulding

restricted to use with small sized devices. For the new

types of products based on large chips, chip makers have

been forced to return to single piston injection systems

using materials with gel times in excess of 25 seconds. In

the search for low shrink, high throughput resins, a

solution has been found with interpenetrating network

materials based on epoxy and silicone compounds.

WORLD

Accession no.522109


23, No.23, 20th June 1994, p.10

JAMAK WRAPS OFFER RELIEVING HEATMiller J

Jamak Fabrication is reported to have introduced Red-E-

Heat, a new range of therapeutical wraps containing a

microwavable silicone compound. The products are

designed to deliver moist heat therapy and orthopaedic

support to arthritis and muscle pain sufferers, the JMK

International subsidiary claims. Details are given.

JAMAK FABRICATION INC.; JMK

INTERNATIONAL INC.USA

Accession no.521390


New Orleans, La., 9th-13th May 1993, Vol.II, p.2034-6.

012

SILICONE RUBBER MOULDING: THE WHATAND WHYDekker C K

Met-L-Flo Inc.,Plas-T-Flo Div.

(SPE)

The use of silicone rubber moulds for casting PU and

epoxy resins is discussed. Aspects of mould making and

design and factors affecting mould life are examined.

USA

Accession no.520557

Item 332Berlin, 1992. 1/11/92. 6E1

RUBBER INSULATED CABLES, WIRES ANDFLEXIBLE CORDS FOR POWERINSTALLATION - UNBRAIDED HEAT-RESISTANT SILICONE RUBBER INSULATEDCABLESVerband Deutscher Elektrotechniker

VDE 0282(PT506)





WESTERN EUROPE

Accession no.520334

Item 333Tokyo, 1993. 1/3/93. 45C



TESTING METHOD FOR ELECTRICALSILICONE RUBBER COMPOUNDSJapanese Standards

JIS-C2123




JAPAN

Accession no.520220

Item 334Philadelphia, Pa, 1992. 11/9/92. 6E1

WIRE, ELECTRICAL, SILICONE RUBBERINSULATED, 150 DEG. C, 1000 VOLTS, GLASSBRAID COVERING, ABRASION RESISTANTUS,Navy

MIL-W-16878/31




USA

Accession no.518409

Item 335Philadelphia, Pa, 1993. 10/2/93. 6H1

HOSE AND HOSE ASSEMBLIES, NONMETALLIC, SILICONE, POLYESTER ANDWIRE REINFORCED (FOR COOLANT ANDHEATING SYSTEMS OF DIESEL & GASOLINEPOWERED ENGINES)US,Navy

MIL-H-62217

Details are given of four types of polyester and wire

reinforced, silicone compounded, elastomeric hose, for

use in coolant and heating systems of diesel and gasoline

engines. Photocopies and loans of this document are not

available from Rapra. It may be purchased from BSI.

Please contact Rapra for further details.

USA

Accession no.518372


176, No.5, May 1994, p.24-5

EMI SHIELDING: A SILVER LINING?

Dunlop Precision Rubber and James Walker & Co. have

both recently introduced new ranges of high performance

conductive elastomers for EMI shielding seals, primarily

needed in aerospace and defence applications. Dunlop

Precision’s range is based on silicones and fluorosilicones,

with metallic or metal-coated fillers. Materials used as

fillers include hollow glass spheres coated with metal,

which gives low weight, and metallised fabric. James

Walker claims its range of conductive elastomers, using

silver-coated glass spheres, give the highest performance

for cost of any conductive elastomer and will cut the cost

of EMI shielding. The company’s Shieldseal 105 material

is an alternative to heavier, more expensive conductive

elastomers originally designed for military uses, it claims.

DUNLOP LTD.,PRECISION RUBBERS DIV.;

WALKER J.,& CO.LTD.EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.512684

Item 337New Scientist

142, No.1923, 30th April 1994, p.21

POLYMER PUTTY MAKES FOR SAFERTUMOUR TREATMENTBeard J

A polymer putty has been developed which will be of use

in shielding healthy tissue from the effects of radiation

used to treat oral tumours. The putty is made from 90-

95% metal powder bound together by polysiloxane. The

putty can easily be shaped around irregular shaped

tumours and also skin melanomas. Further details are

given.

AMERICAN DENTAL ASSOCIATION HEALTH

FOUNDATION; US,NATIONAL INST.OF

STANDARDS & TECHNOLOGYUSA

Accession no.512191

Item 338International Journal of Adhesion & Adhesives

14, No.2, April 1994, p.103-7

HYDROTHERMAL STABILITY OF JOINTS,USING A SILICONE RUBBER ADHESIVE, FOR ARANGE OF ADHERENDS OF INTEREST TOMAKERS OF SURGICALLY-IMPLANTEDMICROELECTRONIC DEVICESDonaldson P E K

London,University College

This paper describes a series of accelerated life tests on

the adhesion between a convenient silicone rubber (Dow

Corning 3140) and a range of adherend materials of which

such structures might be made. It appears that bonding is

by chemisorption and varies in resistance to degradation

in water according to the density of negative charge on

the adherend surface. The work is thought to provide the

beginnings of a rational process for choosing adherend

materials in implant design. 7 refs.

EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.510798

Item 339Adhesives Age

37, No.4, April 1994, p.16/22

APPLICATIONS OF CURED-IN-PLACE



GASKETING TECHNOLOGYDiNicola D; Ledoux R E

Robotics Inc.

It is reported that for more than two decades, silicone

rubber has been the material of choice in many industries

for making formed-in-place and moulded-in-place gaskets

on products ranging from small appliances to automotive

engines. The most common form of sealant has, until

recent years, been room temperature vulcanisation.

Several case histories are outlined which focus on liquid

silicone rubber materials used to form cured-in-place

gaskets onto a variety of products.

USA

Accession no.509900


5, No.4, 1994, p.339-51

CONTROLLED RELEASE OF BETA-ESTRADIOL FROM BIODEGRADABLEMICROPARTICLES WITHIN A SILICONEMATRIXBrannon-Peppas L

Biogel Technology

Biodegradable controlled release systems were prepared

from biodegradable microparticles of poly(lactic acid-co-

glycolic acid) containing beta-estradiol in the presenceor absence of silicone. The release behaviour of beta-

estradiol from free microparticles and from microparticles

embedded within a silicone matrix was compared with

the release behaviour shown by non-encapsulated beta-

estradiol within a silicone matrix. It was found that

incorporating biodegradable microparticles within a

silicone matrix lessened the initial burst of release often

seen with these types of formulations and provided a

controlled rate of drug release. In addition, the release

rate of beta-estradiol from biodegradable microparticles

within silicone was higher than for unencapsulated beta-

estradiol in silicone. This type of formulation could be

useful in a number of instances, such as release of drugs

from implants for which a simple drug-silicone

formulation did not yield desired release behaviour,

formulations which are currently developed for

microparticles but which may need to be removed if

necessary and implant formulations containing drugs

which will not diffuse through silicone. 29 refs.

USA

Accession no.508853

Item 341Modern Plastics International

24, No.3, March 1994, p.20/3

LINE BETWEEN PROTOTYPING,PRODUCTION IS BLURRINGInnace J J; Snyder M R

A recent technical push in rapid prototyping technology

is in the area of short production runs that can yield as

many as 100 low-cost parts in a matter of days. General

Pattern Co. has recently developed an in-house process

using RIM equipment. Mox-Med Inc. is specialising in

the custom prototyping and manufacture of silicone rubber

medical components using the liquid injection moulding

process. MCP Systems Inc., a supplier of automatic

vacuum casting machines, has a system employing

silicone moulds. The company says seven or eight finished

PU parts can be produced per day.

GENERAL PATTERN CO.; MOXMED INC.; MCP

SYSTEMS INC.USA

Accession no.507564

Item 342IRC ’93/144th Meeting, Fall 1993. Conference

Proceedings.

Orlando, Fl., 26th-29th Oct.1993, Paper 112, pp.18.

012

INCREASING THE PROFITABILITY OFSILICONE RUBBER MOULDINGTanton R

Dow Corning STI

(ACS,Rubber Div.)

An examination is made of the advantages in terms of

increased productivity and reduced production costs of

using platinum cure systems in place of peroxides in the

moulding of silicone rubber compounds.

USA

Accession no.505684

Item 343Gummibereifung

69, No.7, July 1993, p.54-6

German

SILICONE RUBBER SUCCESSFUL IN SEALINGJOINTS

Silicone rubber, composed of silicon and oxygen rather

than carbon, is discussed as a material for seals on aircraft

windows and on ovens. The advantages are heat

resistance, cold flexibility, good ageing and weathering

resistance, resistance to ozone and radiation, electrical

insulation. Solid and liquid types of silicone rubber are

described. Further applications are listed, e.g. medical

tubing, rollers, electric cables.

EUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.505580

Item 344Plastics & Rubber & Composites Processing &

Applications

19, No.2, 1993, p.87-92



INJECTION MOULDING OF CUSTOM HIPREPLACEMENT SOCKETSQuek C H; Crawford R J; Orr J F


An investigation is described of the feasibility of injection

moulding hip replacement sockets on a ‘one-off’ basis. A

silicone rubber impression was used to reproduce the

required socket shape in PMMA within a standard mould

backing block. PE was then injected into the mould to

produce good quality mouldings, the PMMA mould

showing little deformation at the moulding temperature

and pressures used. Further process development is

required for the orthopaedic application described but the

process is offered as a means of injection moulding low

numbers of components or for testing prototype mould

designs. 9 refs.


Accession no.505507

Item 345Patent Number: WO 9401496 A1 19940120

METHOD AND DEVICE FOR CUSHIONINGLIMBSBracken R L; Winn R A; Riley N L

Schering-Plough Healthcare Products Inc.

A soft, tacky polysiloxane elastomer, which has specified

tackiness, tensile strength, minimum elongation and tearstrength values, is disclosed. The elastomer may be made

into various cushioning devices with or without a top

cover, such as arch support pads, metatarsal pads, heel

cushions, sheet padding, insoles, toe-crest pads, heel

liners, elbow pads, corn and callus pads, blister pads,

bunnion pads and toe pads.

USA

Accession no.505382

Item 346Progress in Organic Coatings

23, No.3, Feb.1994, p.201-36

SYNTHESIS AND APPLICATIONS OFPHOTOCROSSLINKABLE POLYSILOXANESAbdellah L; Boutevin B; Youssef B

Montpellier,University

This survey reviews the synthesis and curing of

polysiloxanes by UV radiation and electron beams. Three

main kinds of products are described: those formed by

an applied radical mechanism and constituting acrylated

polysiloxanes linked by either Si-OC bonds or Si-C bonds,

or by urethane acrylated polysiloxanes or by the thiol-

enes system; those using a cationic mechanism listing the

epoxy grafted polysiloxanes, the vinyl and the styrenic

corresponding compounds; and a special type of

polysiloxane cured by a noble metal or SiH-Si vinyl. In

each case, the mechanism, photosensitisers, additives,

reactive diluents and apparatus for curing formulations

are given. Some applications and properties of these

products, mainly in the field of coating such as release

papers are described. An attempt is made to relate the

structure of these kinds of polydimethylsiloxanes to their

properties. 149 refs.

EUROPEAN COMMUNITY; FRANCE; WESTERN EUROPE

Accession no.503975


66, No.12, 1993, p.890-4

Japanese

DETERIORATION OF OIL SEALS ANDANALYSISSenda K

NOK Corp.

A discussion is given of the factors such as cracking and

abrasion which affect the service life of oil seals made

from silicone rubbers, and of their investigation by IR

spectroscopy and bench tests. 14 refs. Articles from this



Technology.

JAPAN

Accession no.503825

Item 348Plastics and Rubber Asia

8, No.49, Dec.1993, p.41

INJECTION MOULDING SILICON RUBBERSitard F

Dr.Boy GmbH

The processing of liquid silicone rubber is discussed. The

relatively new material is finding acceptance as an

alternative to solid silicone rubbers and other organic

elastomers. Properties of the material are described, in

particular its good ageing resistance, wide temperature

tolerance, and electrical properties. The advantages of its

processability and high temperature vulcanisation are put

to advantage in industrial scale manufacturing of small

flexible mouldings.


Accession no.501025

Item 349PV International Plastics Magazine

4, No.2, Oct.1993, p.18-9

BACK-FORMING AND LSR PROCESSING INTHE INJECTION MOULDING PROCESS

A new injection moulding machine from Krauss-Maffei

Kunststofftechnik was presented at the company’s in-

house trade fair 1993. The machine is capable of

producing large laminated plastic parts for use, as an

example, in inside panellings of cars, in one single



operation. It is designated KM 800-5700 VIM based on

the vertical injection moulding principle for back-forming

applications. The KM 40-190 C2 injection moulding

machine also presented, is capable of processing liquid

silicone rubber.

KRAUSS-MAFFEI KUNSTSTOFFTECHNIK GMBHEUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.499130


Nov.1993, p.7-8

COATED BREAST IMPLANTS FOUND TORELEASE POSSIBLE CARCINOGEN

Research carried out by Bristol-Myers Squibb and

supervised by the US Food & Drug Administration is

reported to show that silicone breast implants coated with

PU foam release a suspected carcinogen. The studies

confirm earlier suspicions about the implants, which were

marketed under the names of Meme, Replicon and Natural

Y before suspension of sales in 1991.

BRISTOL-MYERS SQUIBB CO.USA

Accession no.498799


66, No.9, 1993, p.660-72

Japanese

SYNTHESIS OF SILICONE POLYMERSInoue H

Osaka Municipal Industrial Research Institute

A review is given of the reactions of formation of silicone

polymers and of the synthesis of silicone-vinyl block

copolymers, silicone-polyester block copolymers,

silicone-polyamide block copolymers, silicone-modified

polyurethane and polyurea, silicone-polycarbonate block

copolymers, silicone-PSF, -PES and -PEEK block

copolymers, silicone graft copolymers, silicone-modified

epoxy resins, silicone IPN and hybrids. 112 refs. Articles

from this journal can be requested for translation by

subscribers to the Rapra produced International Polymer

Science and Technology.

JAPAN

Accession no.498526

Item 352Plastics in Telecommunicatons VI. Conference

Proceedings.

London 16th-18th Sept.1992, p.12/1-12/9. 6E

SYSTEMS FOR SEALING FIRE-RATEDPENETRATIONSRichards J

Dow Corning Hansil Ltd.

(PRI)

Systems which are used to seal penetrations in fire walls

and partitions caused by the passage of cables, pipes and

ducts are described. Silicone foam penetration seals are

included. These systems prevent the spread of flame,

smoke and toxic gases.


Accession no.496029


70, No.725, Sept.1993, p.71-2

French

LIQUID SILICONE RUBBER: MATERIAL OFTHE FUTURESchulze M

Bayer AG

An examination is made of the vulcanisation, injection

moulding, environmental and quality aspects and

applications of Silopren LSR liquid silicone rubbers,

developed by Bayer AG.


Accession no.495691


5, No.10, Oct.1993, p.743-6

ELECTROLUMINESCENT DEVICES BASED ONPOLY(METHYLPHENYLSILANE)Suzuki H; Meyer H; Simmerer J; Jiping Yang; Haarer D

Bayreuth,University

The fabrication of high-efficiency light-emitting diodes

(LEDs) based on sublimed molecular films has attracted

much attention in the search for materials for application

in large-area flat-panel displays. Here, multi-layered

LEDs based on poly(methylphenylsilane)(PMPS) as the

hole transporting material are reported. In contrast to

polyphenylenevinylene, PMPS films exhibit a high

effective mobility of holes, making the material suitable

for fast switching applications. 21 refs.


Accession no.495629


44, No.9, 1993, p.96/8

German

EMBOSSING OF DECORATIVE MATERIALSAND LSR PROCESSING IN THE INJECTIONMOULDING PROCESS

At its in-house trade fair in 1993, Krauss-Maffei

Kunststofftechnik is reported to have presented the following

innovations - a new machine concept for production of large

laminated plastics parts, e.g. the inside panellings in cars in

a single operation; and an injection moulding machine for

processing liquid silicone rubber. Details are given.



KRAUSS-MAFFEI KUNSTSTOFFTECHNIK GMBHEUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.495503


50, No.4, 20th Oct.1993, p.729-33

SWELLING PROPERTIES OF CROSS-LINKEDMAXILLOFACIAL ELASTOMERSAndreopoulos A G; Polyzois G L; Evangelatou M

Athens,National Technical University;

Athens,University

Silicone (Cosmesil SM4) specimens cross-linked with

various amounts of cross-linking agent were studied in

terms of mechanical and swelling behaviour. The

measured tensile modulus allowed calculation of the

average molecular weight between crosslinks.

Equilibrium swelling data were also used, in combination

with the molecular weight between crosslinks data, to

obtain the interaction parameter of various silicone-

solvent systems at 25C. Swelling was studied also for

silicone samples with varying network densities in

selected solvents such as toluene, ethyl acetate, n-butanol

and methyl ethyl ketone. 17 refs.

EUROPEAN COMMUNITY; GREECE; WESTERN EUROPE

Accession no.494886

Item 357China Synthetic Rubber Industry

16, No.5, Sept.1993, p.268-70

Chinese

PREPARATION AND PROPERTIES OFSILICONE RUBBER DISPERSIONZhao Mingxing; Dai Mengxian; Wu Ping; Tong

Jinquan; Duan Wei

China,Ministry of Chemical Industry

Based on previous works, this study describes the

preparation and stability of silicone rubber dispersion.

Stable homogeneous silicone rubber dispersion could be

made by dissolving reinforced GY-31 medical grade

silicone rubber in 1,1,1-trichloroethane, then pounding

in a high speed mill. Thin-walled silicone rubber articles

with complex shapes prepared from the dispersion by dip-

coating or spraying could satisfy clinical uses. 6 refs.

CHINA

Accession no.494209

Item 358BIBRA Bulletin

32, No.4/5, May/June 1993, p.155

SILICONE MEDICAL DEVICES

The FDA is requiring manufacturers to update information

on immune-related disorders in the informed consent

documents for women receiving breast implants in clinical

studies, it is announced. This follows data obtained from

rat studies which supports a possible link between silicone

gel-filled breast implants and autoimmune disorders.

Further brief details are given.

US,FOOD & DRUG ADMINISTRATION

USA

Accession no.489233


44, No.6, June 1993, p.46/50

German

EXTRUSION AND CROSSLINKING OF SOLIDSILICONE RUBBERFuchs P

This review of silicone rubber extrusion examines plant

design and layout, extrusion lines and conditions, mould

engineering, vulcanisation systems and conditions,

ancillary equipment, profile dies and applications.


Accession no.488323

Item 360International Polymer Processing

8, No.2, June 1993, p.178-81

COMPUTER CONTROLLED ROTATIONALMOULDING OF LIQUID SILICONE POLYMERTeoh S H; Guan K W; Lee N H; Wong Y S; Nee A Y C;

Pho R W H

Singapore,National University

Computers have made it possible to control the thickness

of the object accurately. This was made possible by

creating an intelligent software which takes in the

viscosity and density time variation of the polymer. Using

the flat plate withdrawal theory, it computes the new speed

for each axis. The relationship between rotational

moulding parameters and polymeric material properties

for a solvent-silicone rubber system is demonstrated using

a hand prosthesis as an example. The time required for

gelation of the silicone rubber was about 2 hours. 8 refs.

SINGAPORE

Accession no.486519


27, No.7, July 1993, p.867-75

POROUS COLLAGEN SPONGE FOROESOPHAGEAL REPLACEMENTNatsume T; Ike O; Okada T; Takimoto N; Shimizu Y;

Ikada Y

Kyoto,University

A new artificial oesophagus with a bilayered structure

made of porous collagen sponge and silicone was studied.

Microscopic observation of tissue reconstruction and

epithelial regeneration are presented. 41 refs.



JAPAN

Accession no.484268

Item 362Fire & Flammability Bulletin

June 1993, p.7

SILICONE RUBBER DEVELOPMENT PASSESTOUGH SAFETY TESTS

Silicone Altimex has developed a low toxicity/low smoke

silicone rubber, which will have potential for rubber

sealing componentry in the building and transportation

markets. The article supplies details of several stringent

and comprehensive fire and smoke tests passed by the

material. Likely applications include window and door

seals in buildings and transportation.

SILICONE ALTIMEXEUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.484121


70, No.720, Feb.1993, p.58-64

French

APPLICATIONS OF SILICONE RUBBERSSchorsch G

Rhone-Poulenc SA

The structure, properties and applications of

polydimethylsiloxane elastomers are examined. 3 refs.


Accession no.483624


43, No.11, Nov.1992, p.183-5

German

AT K ’92: LIQUID SILICONE RUBBER. A HIGH-PERFORMANCE MATERIAL FOR THEFUTURE

This paper is based on an address given by Dr M. Schulze

of Bayer AG. Liquid silicone rubber is the only type of

crosslinkable rubber that can be processed in liquid form.

Bayer supplies this material as Silopren LSR, a ready-to-

use, two-component liquid silicone rubber for the injection

moulding of small flexible parts and the coating of textile

fabrics.

BAYER AGEUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.480540


36, No.5, May 1993, p.26-31

ISO CLASSIFICATION AND REQUIREMENTSTANDARD FOR FACADE AND GLAZINGJOINT SEALANTS. PART II.

Wolf A T

Dow Corning Corp.

This detailed article evaluates ten commercially available

silicone construction sealants according to the draft

standard of ISO/DIS 11600. Information presented

includes an overall assessment summary. The study

concludes that ISO/DIS 11600 can be regarded as a step

towards international harmonisation of the standards

required within the sealant industry. (This article is the

second part of an article dealing with ISO Classification

and Requirement Standard for Facade and Glazing Joint

Sealants; part one of the article appears in Adhesives Age,

April 1993). 5 refs.

USA

Accession no.480387


14, No.6, May 1993, p.459-64

BIODETERIORATION OF MEDICAL-GRADESILICONE RUBBER USED FOR VOICEPROSTHESES: A SEM STUDYNeu T R; Van der Mei H C; Busscher H J; Dijk F;

Verkerke G J

Groningen,University; Netherlands,Biomedical

Technology Centre

Silicone voice prostheses used for rehabilitation of speechafter total laryngectomy are inserted in a non-sterile

habitat. Deposits on explanted Groningen Button voice

prostheses revealed a biofilm, the result of colonisation

of the silicone surface by bacteria and yeasts. Furthermore,

it was shown by SEM on sectioned explants that the

silicone material was degraded by filamentous and

vegetative yeast cells. The different explants showed a

variety of sharp-edged, discrete yeast colonies. The yeasts

grew just under the silicone surface and up to 700 microns

into the silicone material. Nine different types of defect

in the silicone material created by the yeasts are described.

This degradation of the silicone by yeasts appeared to be

the main cause of failure and of the need for frequent

replacement of the prostheses. 10 refs.

EUROPEAN COMMUNITY; NETHERLANDS; WESTERN

EUROPE

Accession no.478732


207, No.6, March 1993, p.17/22

SILICONE MAKING AUTOS QUIETER THANEVERFinney D L

GE Silicones

Automotive engineers are constantly looking for materials

that serve to dampen vibration and hence reduce noise.

Silicones have found numerous automotive applications

where noise is concerned. Silicone gaskets and bushings



help to reduce noise within the engine, including noise

produced by timing chain mechanisms, valves and other

enclosed moving engine parts. General Motors’ new

Northstar engine incorporates special silicone gaskets to

help reduce noise produced by the air and fuel delivery

systems. Chrysler is using a special silicone coating

system, developed by GE Silicones, as a coating on EPDM

weather stripping for windows and doors.

USA

Accession no.476856

Item 368Chemical Marketing Reporter

243, No.17, 26th April 1993, p.SR34

NEW MARKETSCintron I

GE Silicones reports that although growth in Western

Europe and the US has slowed, the company has seen

double-digit growth for its silicone rubber line in the Asia

Pacific region. Overall the US domestic silicones market

is estimated at over 300 million pounds, serving the three

principal end use sectors of fluids, elastomers and resins.

Dow Corning, with a 45% share of the US market, is to

double capacity at its plant in Barry, Wales, and has

invested in research facilities at its headquarters in

Midland, Mich. and Yamakita, Japan. GE Silicones has a

new applications development centre in Oyama, Japan.

Union Carbide has announced it has finally found a buyer

for its silanes business.

WORLD

Accession no.476623

Item 369Multiple Shot, Insert, and Co-Injection Molding.

Conference Proceedings.

Northbrook, Il., 23rd-24th Oct.1991, p.129-40. 83

INSERT MOULDING WITH SILICONE RUBBERMiller M

Lucas Duralith Corp.

(SPE,Chicago Section; SPE,Milwaukee Section)

This article describes the insert moulding of silicone

rubber keypads produced at Lucas Duralith using the

liquid injection moulding process. Information is

presented on two types of keypad design - diaphragm or

pusher-pad - which are used for a majority of the

company’s products. The use of the compression process

is also briefly mentioned, although the company is said

to only use this process for the moulding of silicone rubber

stock which is then used to produce conductive ‘pills’ or

contacts.

USA

Accession no.473906


14,No.3,1993,p.184-8

IN VITRO ASSESSMENT OF BACTERIALADHESION TO HYDROMER-COATEDCEREBROSPINAL FLUID SHUNTSBridgett M J; Davies M J; Denyer S P; Eldridge P R

Nottingham,University; Brighton,University;

Nottingham,Queens Medical Centre

The adherence of five strains of Staphylococcus epidermis

and one strain of S.aureus to both untreated and

Hydromer-coated silicone rubber cerebrospinal fluid

shunts was studied in vitro using epifluorescent image

analysis. The potential of the Hydromer coating in creating

biomaterial surfaces which reduce the initial adhesion of

bacteria is demonstrated, with a view to reducing the

incidence of biomaterial-related infections. The

importance of uniformity of coating along the lumen of

cerebrospinal fluid shunts is highlighted. 14 refs.


Accession no.472417


19,No.11,1993,p.T/9-11

NON-HALOGEN-CONTAINING ELASTOMERCOMPOSITES OF LOW COMBUSTIBILITYMerkulova T A; Voloshin V N; Mikhlin V E; Kozlova

G S

It was confirmed that vulcanisates of siloxane polymers

with phenyl substituents at the silicon atom are more flame

resistant than polymers containing vinyl and methyl

substituents. A dependence of the time of extinguishment

of specimens on the composition and structure was

established. Compositions developed with increased

flame propagation resistance, based on SKEP (EPM) and

SKEPT (EPDM) and containing aluminium hydroxide,

are recommended for introduction in the production of

cables for ships, shafts and underground railways. 4

refs.Translation of Kauch.i Rezina,No.3,1992,p.10

RUSSIA

Accession no.472378

Item 372Advances in Pressure Sensitive Adhesive Technology

1.

Warwick,RI,1992,p.50-76. 6A1

CHEMISTRY AND TECHNOLOGY OFRADIATION CURABLE SILICONE RELEASECOATINGSEckberg R P

General Electric Co.,Silicones Div.

Edited by: Satas D

(Satas & Associates)

A brief discussion is presented on the UV- and electron

beam curing of silicone release agents followed by an

overview of radiation curable silicones. These silicones



include acrylated silicones, mercapto-vinyl silicone

systems and cationic radiation curable silicones. Mention

is also made of controlled release additives for silicone

systems. 49 refs.

USA

Accession no.469337

Item 373Materials News International

No.39,1993,p.8-9

BRINGING RELIEF TO OVER ONE MILLIONPEOPLESwanson A B

Dow Corning Europe SA

Replacement joint implants are described which are made

of three grades of Silastic elastomers, and which are used

in the treatment of arthritis.


Accession no.469318


No.1469,23rd Jan.1993,p.9

THERMOSETS RESTRICTED TO NICHEMARKETS IN THE FUTURE

Krauss Maffei has developed a two component injection

moulding machine to mould polyester BMC valve covers

with integral seals in LSR. KM has developed its new

modular machine concept to assist thermoset processors.

To change from thermoplastics to thermosets moulding

simply involves changing the injection unit and the cards

in the control system. A new machine concept was

developed and this was based upon three stages of

processing. These were the optimised processing of BMC

and LSR and the use of a turntable mould. The KM

patented AZ unit provides fully automatic material supply.

KRAUSS-MAFFEI (UK) LTD.EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.468591


37,No.11-12,1992,p.504-7

Polish

UTILISING THE DAMPINGCHARACTERISTICS OF SILICONE POLYMERSIN SHOCK-ABSORBING STRUCTURES ANDTECHNOLOGYMaciejewski J


The damping characteristics of Polastosil ABM, a range

of siloxane polymers used in shock-absorbing materials,

and their main useful properties and potential applications

are discussed. The design and the static and dynamic

characteristics of a railway buffer constructed using this

type of material, as well as results from the author’s own

studies on the use of Polastosil in the construction of car

suspensions, are also presented.Articles from this journal




Accession no.467735


37,No.11-12,1992,p.499-503

Polish

SILICONES AS MATERIALS WITH A FUTUREIN POLANDRosciszewski P; Zielecka M


A brief review is presented, with reference to published

papers and patents, of the history and results of research

at the Zoliborz Chemical Institute in the field of synthesis,

processing and applications of various organosilicon

monomers and polymers. The main commercially

developed manufacturing processes and the development

of production and application of silicones in Poland are

discussed. A table listing the tested and currently

manufactured products with their names is given. It is

pointed out that there is a considerable delay in the

consumption of silicones in Poland in terms of quantity

and range as compared with the industrially developed

countries. 94 refs.Articles from this journal can be

requested for translation by subscribers to the Rapra



Accession no.467734

Item 377Paper, Film & Foil Converter

66,No.10,Oct.1992,p.74/8

SILICONE TECHNOLOGY TAPS PSA MARKETOPPORTUNITIESHandt C M; Kelly D T

The use of silicone technology in pressure-sensitive

applications is discussed in detail, with special reference

to difficult environments, e.g. when adhesives must resist

moisture, chemicals and extreme temperatures.


Accession no.467294

Item 378PV International Plastics Magazine

Oct.1992,p.82/5

HIGH-PERFORMANCE MATERIAL FOR THEFUTURE

The production and application of Bayer’s Silopren LSR,

is described. The two-component, liquid silicone rubber



is suitable for injection moulding small parts and coating

textile fabrics. Applications include protective clothing,

electronic applications, automotive applications, medical

applications and many others.

BAYER AGEUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.467145


May 1992,p.92-3

FAST CURING FOR OPTICAL FIBRESDennis W E; Burke D W

Dow Corning Corp.

The use of UV cured silicone polymers in optic fibre

coatings is examined, and advantages over heat cured

silicone polymer and UV cured acrylic polymer coatings

are described.

USA

Accession no.466464


69,No.715,June/July 1992,p.58-62

French

SILICONE TECHNOLOGY IN THE SERVICE OFELECTRONICSGensler G

GE Silicones

An examination is made of the thermal and dielectric

properties, heat resistance and weathering characteristics

of silicone rubbers for use in electronic applications,

including coatings, potting compounds, adhesives and

transfer moulded components.

USA

Accession no.466444

Item 381Materials Engineering

109,No.9,Sept.1992,p.21-2

SILICONE FOAMS LIGHTEN UPHartley K R

GE Silicones

Silicone elastomer foams are reviewed. Their

processability, performance, properties and applications

are discussed in some depth, with particular emphasis on

their stability, fire retardance properties and lower smoke

generation and toxicity than organic foams.

USA

Accession no.465884

Item 382High Performance Textiles

Oct.1992,p.4-5

YARN COATING TECHNIQUE

Cogent Ltd. of London, has developed a treatment in

which a cord or strand can be coated with a dilute solution

of a polysiloxane prepolymer which is then pre-cured in-

situ to create a protective sheath around the yarn

encapsulating it. The article supplies comprehensive

details of the process which is seen as having special

relevance to the production of improved dental floss. (US

patent number 5 021 267).

COGENT LTD.EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.465845

Item 383142nd Meeting,Fall 1992,Conference Proceedings.

Nashville,Tn.,3rd-6th Nov.1992,Paper 93,pp.24. 012

COMPRESSION STRESS RELAXATION. II. ANIMPROVEMENT OVER TRADITIONAL TESTSFOR THE EVALUATION OF SEALANTMATERIALSBunting W; Slocum G H; Russell W D

GE Silicones

(ACS,Rubber Div.)

A compression stress relaxation test method consistent

with ISO 3384 for the evaluation of rubber sealing

materials is described. The test measures important

material performance characteristics not measured bytraditional test methods. A comparison of compression

stress relaxation test results with compression set, volume

per cent swell, oil immersion and heat ageing is made

using heat cured silicone rubber and acrylic elastomer oil

pan gasket materials. 2 refs.

USA

Accession no.465622


26,No.8,Aug.1992,p.979-87

SHORT-TERM RESPONSE OF BRAIN TISSUETO CEREBROSPINAL FLUID SHUNTS IN VIVOAND IN VITRODel Bigio M R; Fedoroff S

Manitoba,University; Saskatchewan,University

The results are reported of a study carried out to determine

how gross physical characteristics of cerebrospinal fluid

shunts and the cellular proliferative response to shunts

contribute to shunt obstruction. The shunt tubing

employed was made of barium-impregnated, silver-

impregnated or unimpregnated silicone rubber. Contact

between the shunt catheter and vascularised brain tissue

was found to be the most important factor in the genesis

of shunt obstruction. 21 refs.

CANADA

Accession no.463797



Item 385Composites Plastiques Renforces Fibres de Verre

Textile

32,No.3,May/June 1992,p.376-80

MANUFACTURING A VALVE COVER WITHSEAL IN ONE WORK STAGESchultheis S M

KRAUSS-MAFFEI AG

Details are given of an injection moulding machine with

which it is possible to produce an automotive valve cover

in glass fibre-reinforced unsaturated polyester BMC

together with its seal of liquid silicone rubber in one cycle.

The manufacturing costs for this process are compared

with those for the traditional two-stage operation.

GERMANY

Accession no.462092


43,No.5,May 1992,p.126/9

German

IMAGE PROCESSING SYSTEM FOR THEAUTOMATIC TESTING OF SILICONE RINGS

A South German company has developed an automatic,

optoelectronic testing system whose possibilities include

the a testing of silicone rings for various types of defect.

The system has been designed in such a way that it

requires no subsequent development or modification, and

can be readily adapted both to the actual parts produced

and to the user’s testing requirements. The entire system,

including testing process, operation of the system and its

capabilities, is described.

WIDMANN BILDVERARBEITUNGSSYSTEME

OHGGERMANY

Accession no.462057

Item 387Rubber and Plastics News 2

3,No.17,15th June 1992,p.4

DOW CORNING OFFERINGS STRESSCUSTOMER SUPPORT

Dow Corning has introduced a range of marked silicone

tubing, and a range of silicone materials for medical

applications. Dow works with its customers to make

materials for specific applications. In particular, details

are given of Silastic Rx marked tubing, made from 50

durometer, medical grade silicone elastomer. Also

mentioned is a series of silicone urethane copolymers, a

clear adhesive gel technology, a silicone elastomer foam,

two-part liquid silicone rubbers, and technology for a one-

part formulation of optically clear, medical-grade

elastomers.


Accession no.461100

Item 388Polimeri

13,Supplement 1,1992,p.35-8

Serbo-Croatian

SILICON INSULATORSMardesic O;Tisov J;Zelic N

Previously reported data on silicone insulators are

reviewed. The properties of insulators made from silicone

and ceramics are compared and end-use applications

indicated. 9 refs.

EASTERN EUROPE; YUGOSLAVIA

Accession no.461007

Item 389Journal of Applied Biomaterials

3,No.3,Fall 1992,p.239-42.

CLINICAL REVIEWS: MAMMARY IMPLANTSKossovsky N;Papasian N

CALIFORNIA,UNIVERSITY AT LOS ANGELES

The use of silicone rubbers and PU foams in mammary

implants is reviewed with reference to aspects of

bioreactivity, degradation and carcinogenicity. 38 refs.

USA

Accession no.460974

Item 390Materiaux & Techniques

80,No.1-2-3,1992,p.51-4

French

SOLVENTLESS SILICONE COATINGMATERIAL FOR SURFACE MOUNTEDELECTRONIC COMPONENTSPiazza J;Dinallo A J

GE SILICONES

The use of solventless silicone encapsulating materials

for surface mounted electronic components is discussed

with reference to those developed by GE Silicones. Details

are given of their properties, applications and methods of

polymerisation.

USA

Accession no.459670

Item 391Machine Design

64,No.14,9th July 1992,p.52-3

MINERAL-REINFORCED SILICONES TAKETHE HEATDinallo J

GE SILICONES

The features and end-use applications of mineral-filled

silicone polymers, which can be used as replacements for

metals and injection moulded to produce components

withstanding operating temps. as high as 275C continuously,

are described. Applications include encapsulation for



electronic devices, automotive components and domestic

appliances. Fillers employed are generally fused amorphous

silica and a small amount of E-glass.

USA

Accession no.459325


36,No.4,April 1992,p.35-8

Italian

SILICONE RUBBER IN THE AUTOMOTIVEINDUSTRYBourrain P

RHONE-POULENC SA

The use of silicone rubbers in automotive components is

discussed, and the properties and applications of materials

produced by Rhone-Poulenc are described. These include

Rhodorsil heat curing and Rhodorseal room temperature

curing silicone rubbers. Applications examined in particular

detail include seals, spark plug boots, ignition cables,

coolant and heater hoses and oil pan gaskets. 2 refs.


Accession no.458545


69,No.714,May 1992,p.64-6.

French

THINK VACUUM CASTINGCottineau F

MCP EQUIPMENT

An account is given of the MCP process for vacuum

casting prototypes in two-component resins using silicone

rubber moulds.


Accession no.457572

Item 394Adesione

3,No.1,Jan/Feb.1992,p.16-24

NEW APPLICATIONS OF SILICONES IN THEBUILDING INDUSTRYMusci G

GENERAL ELECTRIC CO.

(In Italian, English and French). The chemistry, molecular

structure and main physical and chemical properties of

silicones are outlined. New applications of silicones in the

building industry are discussed, including structural glazing,

flame retardant barriers, roofing systems and as an opaquing

agent for reflective glass. Detailed comparative results are

given for accelerated ageing tests and weather resistance of

silicone, PU, butyl elastomer, neoprene + chlorosulphonated

PE, chlorosulphonated PE and vinyl elastomer.

EUROPEAN COMMUNITY; ITALY; WESTERN EUROPE

Accession no.457129

Item 395Adesione

3,No.1,Jan/Feb.1992,p.10-5

SILICONE MASTICS IN THE BUILDINGINDUSTRYHoude M

RHONE-POULENC SA

(In Italian, English and French). The use of silicone

mastics in the building industry is reviewed. Different

silicone mastic formulations and their properties are

discussed, and weathering tests are described. Many

types of silicone sealants are now available. All have

different properties to suit specific requirements, but

all are weatherproof. Durability combined with

elasticity, adhesion to the substrate and chemical

resistance account for the increasing use of silicone

sealants in the building industry. Special reference is

made to the ‘Vitrage Exterieure Colle’ building

technique in which glass elements are bonded and

sealants have to maintain their adhesion properties,

long-term, under all weather conditions.


Accession no.457128


19,No.2,1992,p.T/33-40

VULCANISATION OF SILICONE RUBBERSSchaetz M

A review of silicone rubber vulcanisation since the 1950s

is given with emphasis on reaction mechanisms and side

reactions. Methods considered are peroxide vulcanisation,

radiation vulcanisation, hydrosilylation reactions and

condensation vulcanisation of functional groups by

reactive crosslinking agents. Applications, e.g. adhesives

and sealants, and specific advantages of each technique

are pointed out. 34 refs. (Full translation of Plasty a

Kaucuk,No.1,1991,p.5).

CZECHOSLOVAKIA; EASTERN EUROPE

Accession no.456643

Item 397Contraception

45,No.5,May 1992,p.453-61

ACCEPTABILITY OF NORPLANT-2 RODS AS AMETHOD OF FAMILY PLANNINGSingh K;Viegas O A C;Ratner S S

SINGAPORE,NATIONAL UNIVERSITY HOSPITAL

Details are given of a five-year contraceptive study using

the Norplant-2 rod system which consisted of two PDMS

rods in which levonorgestrel was incorporated. 5 refs.

SINGAPORE

Accession no.455249




13,No.5,1992,p.333-6

DIMENSIONAL STABILITY OFCONDENSATION SILICONE RUBBERSBraden M

LONDON,UNIVERSITY

Linear shrinkage during 24h after setting of a number of

proprietary condensation silicone dental impression

materials was studied. Weight loss and change in volume

were measured over the same time period by weighing

similar specimens in air and water. It was concluded that

the linear shrinkage of condensation silicone rubbers is,

to a first approximation, predictable from the mass of

volatile products lost, with the exception of the highly

filled putty materials. In the latter case the measured

changes are much larger than those predicted theoretically;

this may be a consequence of strains built in during

moulding of specimens. 5 refs.


Accession no.454392


26,No.5,May 1992,p.631-50

DIFFERENCE IN TUMOUR INCIDENCE ANDOTHER TISSUE RESPONSES TOPOLYETHERURETHANES ANDPOLYDIMETHYLSILOXANE IN LONG-TERMSUBCUTANEOUS IMPLANTATION INTO RATSNakamura A;Kawasaki Y;Takada K;Aida Y;Kurokama

Y;Kojima S;Shintani H;Matsui;Nohmi T;Matsuoka

A;Sofuni T;Kurihara M;Mitaya N

JAPAN,NATIONAL INST.OF HYGIENIC

SCIENCES; JAPAN,PUBLIC WELFARE INST.OF

SCIENTIFIC RESEARCH

The long-term (1- and 2-year) adverse tissue responses

including tumour formation by subcutaneous implantation

of PU and silicone films into rats were compared. Tissue

responses around implants were classified into four

groups: (a) tumour, (b) atypical cell proliferation

accompanied by preneoplastic changes, (c) cell

proliferation without preneoplastic changes, (d) no

obvious responses. In both implantation periods, the PUs

gave higher incidents of adverse responses including

tumour formation in comparison to silicone. 29 refs.

JAPAN

Accession no.453090

Item 400Plastics Technology

38,No.5,May 1992,p.78-80

NEW PLASTICS FOR ELECTRONICS

GE Plastics has expanded its Supec PPS line with the

introduction of high ductility and low-flash grades for

surface mount technology and high-performance

connectors. GE Silicones has introduced two new silicone

moulding compounds for electronics and electronics

packing. Hercules has unveiled a brand new resin

chemistry, Sycar silicon-carbon thermosets. They are

currently available in neat resin grade for multilayer

circuit boards and a formulated liquid resin for potting

and encapsulating.

GE PLASTICS; GE SILICONES; HERCULES INC.USA

Accession no.452191

Item 401Advances in Polymer Technology

11,No.2,Summer 1991/92,p.133-40

INITIATION OF A SOLID-STATE EXTRUSIONOF A CROSSLINKED SILICONE RUBBERCohen A;Burmester A F

DOW CHEMICAL CO.

The initiation stage of a plunger-driven extrusion of a

crosslinked silicone rubber material was investigated. The

experiments were performed at room temp. with a series

of capillaries of various diameters positioned in a

conventional Instron rheometer. It was observed that the

extrusion of the rubber started with a cylindrically shaped

‘plug’ which was followed by an ‘apple peel’ shape. This

change in the shape of extrudates corresponded to changes

in the load applied to the plunger. Analysis of this

transition and its variation with the size of the capillary

indicated that interesting physical mechanisms were

involved in this solid-phase processing operation. 14 refs.

USA

Accession no.451474

Item 402Journal of Microencapsulation

9,No.2,April-June 1992,p.183-6

MICROENCAPSULATION OF MENADIONESODIUM BISULPHITE WITH PDMS BY THESPRAY-DRYING PROCESS.CHARACTERISATION BY THERMALANALYSISGronchi P;Del Rosso R;Centola P;Cosentino R F

MILANO,POLITECNICO

Menadione sodium bisulphite was microencapsulated

with a PDMS membrane using spray-drying technology.

Products were characterised by DTA and chemical and

physical methods. 6 refs.

EUROPEAN COMMUNITY; ITALY; WESTERN EUROPE

Accession no.451328


64,No.5.1st March 1992,p.347/56

PRESERVING OUR HERITAGE IN STONE



Wheeler G S;Schein A;Shearer G;Su S H;Blackwell C

S

IOWA,UNIVERSITY; NEW

YORK,METROPOLITAN MUSEUM OF ART;

SCIENCE & TECHNOLOGY COMMUNICATIONS;

UNION CARBIDE CORP.

Developments in stone consolidation techniques for use

in art conservation are discussed with particular reference

to the use of alkoxysilane monomers or oligomers to form

crosslinked silicate polymers within the matrix of stone

objects. 14 refs.

USA

Accession no.450279


No.1438,6th June 1992,p.8

GE UNVEILS EUROPEAN FUTURE

Silicones are reported to be some of the most versatile

rubber materials on the market, capable of resisting many

chemicals and solvents as well as operating over a wide

temperature range. GE Silicones currently turns over

approximately 650 million US dollars/yr. in these

materials; some of the key developments that the company

sees as being important in the future are outlined.

GE SILICONESEUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.450048

Item 405Macplas

17,No.135,Jan/Feb.1992,p.68-9

Italian

LIQUID SILICONES

A system developed by Ubalit for liquid silicone rubber

processing uses MIR injection moulding machines and

precision moulds produced by the Multicadd computer

aided design and manufacturing system. Some

applications of the process are described.

FIAT SPA; MICROSYSTEM; MIR SPA; UBALITEUROPEAN COMMUNITY; ITALY; WESTERN EUROPE

Accession no.448074

Item 406Journal of Macromolecular Science A

28,No.11-12,Nov/Dec.1991,p.1151-76

SYNTHESIS AND CHARACTERISATION OFPOLYSILANESMatyjaszewski K;Cypryk M;Frey H;Hrkach J;Kwan

Kyu Kim;Moeller M; Ruehl K;White M

CARNEGIE-MELLON UNIVERSITY

The various methods of synthesis of polysilanes are

reviewed aimed at improving control of the polymer

structure and other properties in copolysilanes of various

composition. Particular attention is paid to sonochemical

reductive coupling, ring-opening polymerisation,

modification of polymethylphenylsilylene and solid-state

transitions in copolysilanes. 47 refs.

USA

Accession no.446966

Item 407Progress in Rubber and Plastics Technology

7,No.4,1991,p.308-24

SILICONE ELASTOMERS. TOXICOLOGICALAND OTHER SAFETY ASPECTSCassidy S L

DOW CORNING LTD.

The safety profile of silicone elastomers is reviewed, with

emphasis on major areas of potential hazard, including

toxicity, biodurability, behaviour in fire and elevated

temp., chemical migrants and contaminants, and food

contact and biomedical applications. It is shown that

silicone elastomers exhibit significantly more benign

characteristics than other competing elastomers offered

for the same end-use applications. 63 refs.


Accession no.446907


45,No.2,Feb.1992,p.76-8

German

NEW SEALANTS BASED ON SILANE-MODIFIED POLYMERSProbster M

TEROSON GMBH

(Paper given at Eurobond 1991 in Wiesbaden). Sealants

formed from polyoxypropylene diol with silyl end-groups

show a high rate of cure, have good UV resistance and

will take paint readily. The properties of a number of such

sealants are described and examples of their application

are given.

GERMANY

Accession no.443327

Item 409Plastics Design Forum

17,No.1,Jan/Feb.1992,p.16

SILICONE ELASTOMER IMPLANTS HELPRELIEVE ARTHRITIC PAIN

Dow Corning is reported to have led development for 20

years in small-bone orthopaedic implants produced from

medical grade silicones. Now, flexible finger, wrist and

toe implants made from the company’s Silastic 100 high

performance silicone elastomer also include titanium

shields or grommets. These are claimed to help prevent

damage to the implants from rough bone edges. Details

are given.



DOW CORNING CORP.; DOW CORNING WRIGHT;

TAMCENAN INC.USA

Accession no.443172

Item 410Advanced Composites Engineering

Feb.1992,p.10-1

IT’S IN THE BAGCooke M

AEROVAC SYSTEMS (KEIGHLEY) LTD.

Vacuum bugging is reported to be a widely-used technique

for moulding advanced composite components. The

technique has conventionally been achieved using a high

temperature, heat stabilised nylon film as the membrane.

The advantages and disadvantages of re-usable silicone

rubber vacuum bags compared to disposable nylon ones

are discussed in detail.


Accession no.442996


174,No.3,March 1992,p.16

SILICONE FEMRING SEEKS D H OKBebbington S

It is reported that women in UK may be the first to have

a new long term contraceptive device; the manufacturer,

Roussel Laboratories, is waiting for the Department of

Health to licence the silicone rubber intra-vaginal ring

which emits contraceptive hormones. Details are given.

ROUSSEL LABORATORIES; SILICONE

DEVELOPMENTS LTD.; UK,DEPT.OF HEALTH;

WORLD HEALTH ORGANISATIONEUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.442133

Item 412Elastomerics

124,No.1,Jan.1992,p.23-4

SILICONE GASKETS INSTALLED IN RACECARS TAKE DRIVERS ACROSS THE FINISHLINE

Select-Sil moulded valve covers and oil pan gaskets from

Freudenberg-NOK General Partnership are demonstrated

to be able to keep automotive engines leak-free at

temperatures as high as 500F. They are used in the

Chevrolet cars and light trucks, and have performed in

the Chevrolet Corvette which won the SCCA World

Challenge Series Team championship. The silicone

gaskets are re-usable and have shown great durability and

reliability.

FREUDENBERG-NOK GENERAL PARTNERSHIPUSA

Accession no.441194


124,No.1,Jan.1992,p.10-3

SILICONE HOSES WITHSTAND HIGH HEAT INTURBOCHARGED CLASS 8 TRUCK ENGINESBayne D;Romanowski R;Arthur M

DOW CORNING CORP.; GATES RUBBER CO.

Due to recent changes in EPA emissions standards, truck

manufacturers have been encouraged to use turbocharged

engines to improve fuel economy and reduce output

emissions. Higher operating temperatures have in turn

led to the design of alternative cooling methods for the

charged air to improve fuel efficiency. Air to air methods

of cooling are described and the market which has opened

up for hose materials which will withstand the high heat

environment over long periods of time without significant

degradation. Silicone rubber and the new generation of

silicones which retain plasticity are evaluated.

USA

Accession no.441193


204,No.6,Sept.1991,p.14-5

LIQUID SILICONES - TAKE TWOMenough T

Information is presented in some detail on liquid siliconerubber systems (LSR), how they come to be

commercialised and how Liquid Silicone Molding

Laboratories (LSM Labs.) became established.

Advantages of these systems over conventional gum

rubbers, details of how to injection mould LSR and

potential problems are also discussed.

LIQUID SILICONE MOLDING LABORATORIESUSA

Accession no.434455

Item 415Adhesion.Principles and Practice for Coatings and

Polymer Scientists.Conference Proceedings.

Kent,Oh.,20th-24th May 1991,Paper 10. 9(12)4

COUPLING AGENTS AS ADHESIONPROMOTERS IN ADHESIVE BONDINGBoerio F J;Dillingham R G;Ondrus D J

CINCINNATI,UNIVERSITY

Edited by: Krauss C J

(Kent State University)

The characteristics of silane primer films applied to metals

and the use of silane primers to enhance the hydrothermal

stability of adhesive bonds to metal are presented. Emphasis

is given to iron/epoxy adhesive joints, titanium/epoxy

adhesive joints, aluminium/epoxy adhesive bonds, rubber

to metal bonding, adhesion of PE to sapphire. 38 refs.

USA

Accession no.430273



Item 416137th Meeting Spring 1990.Conference Preprints.

Las Vegas,Nv.,29th May-1st June 1990,Paper 14. 012

SILICONES IN MEDICAL MARKETS - PAST,PRESENT AND FUTUREBrodhagen T W

DOW CORNING CORP.

(ACS,Rubber Div.)

A review is presented of the historic progression of the

use of elastomeric silicones in medical and pharmaceutical

product markets in the USA. Information is included of

the testing of the biocompatibility of materials, process

controls for the manufacture of these materials, and

regulatory implications for their use in device

applications. 6 refs.

USA

Accession no.430144

Item 417Materials News International

No.37,p.6

SILICONE ENCAPSULANT RESISTSCORROSIVE SPACE HAZARDDOW CORNING CORP.

The structure of the Hubble Space Telescope’s solar array

panel, with its 48, 760 silicon solar cells, and its

deployment in space are described. For the flexibleblankets of the solar generator to survive the harsh

environment of an orbit 600km above the earth for five

years, a special multi-laminate compound was developed.

Its structure is described and illustrated. The silver mesh

used for power transfer is surrounded by a symmetrical

sandwich of silicone adhesive, Kapton and glass-fibre

filled with Dow Corning’s space grade encapsulant. The

properties of this encapsulant are listed and other space

applications of it are given.

EUROPEAN COMMUNITY; UK; USA; WESTERN EUROPE

Accession no.425031


42,No.9,5th May 1991,p.2397-403

PERMEABILITY OF SILICONE POLYMERS TOHYDROGENBhide B D;Stern S A

SYRACUSE UNIVERSITY

Permeability coefficients for hydrogen in ten different

types of silicone polymer membranes were measured

in the temp. range 10C to 55C and at pressures up to

about 6.8 atm. Polymers were polydimethyl siloxane,

polyethylmethyl siloxane, polymethylpropyl siloxane,

polymethyloctyl siloxane, polymethyltrifluoropropyl

siloxane, polymethylphenyl siloxane, polydimethyl

silmethylene, polysilethylene siloxane, polysilhexylene

siloxane and poly-m-silphenylene siloxane.

Permeability coefficients decreased slightly with

increasing pressure difference, but increased with

increasing temp., the activation energies being from

1.4 to 4.3 kcal/mol. Permeability coefficients decreased

with increasing bulkiness of functional groups and

decreased considerably when Si-O bonds were replaced

by Si-C bonds. Relevance to gas separation is

suggested. 12 refs.

USA

Accession no.424146


42,No.2,20th Jan.1991,p.383-9

PERMEATION OF DISSOLVED CARBONDIOXIDE IN SYNTHETIC MEMBRANESNakagawa T;Naruse A;Higuchi A

MEIJI,UNIVERSITY

Permeability coefficients of dissolved carbon dioxide

in polydimethyl siloxane, oxygen plasma-treated

polydimethyl siloxane, PS, LDPE and polyamide-6

membranes were studied by applying a carbon dioxide

electrode in a liquid to liquid diffusion cell. Boundary

layer resistance was estimated for the plasma-treated

and non-treated polydimethyl siloxane. Plasma

treatment, which made the surfaces hydrophilic

without changing polymer bulk properties, decreased

the boundary layer’s thickness and increased the

apparent permeability coefficient in the liquid phase.

18 refs.

JAPAN

Accession no.418477

Item 420Integration of Fundamental Polymer Science and

Technology.

Barking,Elsevier Science Publishers,1989,p.308-12.

012

CONFORMATIONAL DISORDER INPOLYDIETHYLSILOXANE (PDES)Kogler G;Loufakis K;Bahnert R;Moller M

FREIBURG,INSTITUT FUR

MAKROMOLEKULARE CHEMIE

Edited by: Lemstra P J;Kleintjens L A

(Eindhoven,University of Technology; DSM

Research BV)

DSC, solid state NMR, optical microscopy and

rheological measurements were used to examine the phase

diagram of polydiethylsiloxane. The mobility of the chains

in the different phases was investigated. Changes that

occurred upon shearing and the influence of quenching

are discussed. 6 refs.

EUROPEAN COMMUNITY; WEST GERMANY; WESTERN

EUROPE

Accession no.416691



Item 42143rd Annual Conference and Focus ’88;Proceedings.

Cincinnati,Ohio,1st-5th Feb.1988,Session 24-B,pp.4. 627

BONDING TO PLASTIC SURFACES THROUGHSILANE PRIMERS AT MODERATETEMPERATURESPlueddemann E P

DOW CORNING CORP.

(SPI,Reinforced Plastics/Composites Institute)

Silane primers have been developed that will give water

resistant bonds of virtually all thermoplastics to metals or

silaceous surfaces if the polymer is fused against the primed

surfaces. The same primers may be effective in bonding a

lower-melting polymer in its fused state against another

primed higher melting polymer. In some circumstances

adhesion between polymers is desired where fabrication

conditions are limited to room temperature or only mildly

elevated temperatures. A partially hydrolysed vinylbenzyl

cationic silane (Z6032) was especially effective on oriented

polyethylene fibres. A new silane modified melamine resin

was especially effective in bonding urethanes to

engineering thermoplastics either as a primer or as an

additive to the urethanes. 7 refs.

USA

Accession no.414880

Item 422Adhasion

34,No.11,Nov.1990,p.32/5

German

ECONOMIC JOINTING WITH SILICONERUBBEREngelmann H

PCI POLYCHEMIE

A description is given of the uses and advantages of

silicone rubber sealants in the building industry.

GERMANY

Accession no.411463


67,No.696,May 1990,p.224-5

French

ADHESIVE AND NON-ADHESIVE BEHAVIOUROF SILICONE COMPOSITIONSSchorsch G

RHONE-POULENC SA

The nature of silicone polymers is discussed and examples

of adhesive and non-adhesive behaviour given. The

dichotomy is further elaborated under three headings: (a)

the behaviour of a dimethylsilicone chain on a solid

surface, (b) the properties of RTV silicones and (c) the

properties of accelerated RTV silicones, recently

introduced for silicone coatings.


Accession no.410348

Item 424Materiale Plastice

27,No.1,Jan/March 1990,p.50-3

Rumanian

SILICONE RUBBERS. I. CONTRIBUTIONS TOSILICONE RUBBER SYNTHESIS BY HOTVULCANISATIONMarcu M;Stiubianu G;Lazarescu S E;Streba E;Stanciu

A

INSTITUTUL DE CHIMIE MACROMOLECULARA

PETRU PONI

A review is presented of results on the synthesis of hot

vulcanised silicone rubbers. The anionic and cationic

polymerisation, compounding and vulcanisation of the

rubbers are discussed. 22 refs.

EASTERN EUROPE; RUMANIA

Accession no.408497

Item 425Handbook of Elastomers.

New York,Marcel Dekker Inc.,1988,p.551-615. 011

ADVANCES IN SILICONE RUBBERTECHNOLOGYPolmanteer K E

KEP ENTERPRISES

Edited by: Bhowmick A K;Stephens H L

34 refs.

USA

Accession no.406504


2,No.9,Sept.1990,p.398-404

CERAMICS FROM ORGANOMETALLICPOLYMERSPeuckert M;Vaahs T;Brueck M

HOECHST AG

This review of non-oxide ceramics concentrates mainly

on the preparation and properties of silicon preceramic

polymers. Silicon carbide and silicon nitride precursors

are discussed in detail. Pyrolysis converts the polymers

into the ceramic state. The inorganic polymers can be

liquefied and are soluble, which offers advantages over

ceramic powder or metallurgical processing and gives rise

to many novel applications such as ceramic coatings,

binders, impregnations or spun fibres. 70 refs.

HOECHST AG; NIPPON CARBON CO.; UBE

INDUSTRIES LTD.EUROPEAN COMMUNITY; WEST GERMANY; WESTERN

EUROPE

Accession no.406448


202,No.3,June 1990,p.33-7



SILICONE USAGE EXPANDING IN EUROPEANAUTOMOTIVE APPLICATIONSFinney D

GENERAL ELECTRIC CO.,SILICONES DIV.

The versatility of silicone chemistry, couple with the

reliability, safety and superior performance of these

inorganic materials is cited for their ability to penetrate

approximately 40 applications on the average US

automobile. A number of present and potential automotive

applications are described particularly in engine hot spots.

USA

Accession no.404022

Item 428Journal of Materials Science

25,No.6,June 1990,p.3017-23

GAS-INDUCED DAMAGE IN ELASTOMERICCOMPOSITESBriscoe B J;Zakaria S

LONDON,UNIVERSITY,IMPERIAL COLLEGE

Damage in elastomers caused by gases escaping from the

polymer matrix was studied using transparent silicone

elastomer (Sylgard 184) filled with low concentrations

of glass spheres that had been given various surface

treatments to improve or reduce polymer-filler interaction.

Optical microscopy techniques were developed to

examine the internal cracks found during a typical gas-induced rupture cycle. Stress-strain data indicated that

the filler particles significantly modified the stress fields

in the elastomer during gas-induced rupture. Use of

dynamic mechanical properties as a guide to the extent

of damage is discussed. 18 refs.


Accession no.403669

Item 429Tech XIII.Proceedings of the Pressure Sensitive Tape

Council’s Thirteenth Annual Technical Seminar.

Itasca,Il.,2nd-4th May 1990,p.155-58. 6A1

ADHESIVE/SILICONE INTERFACEJones J D

DOW CORNING CORP.

(Pressure Sensitive Tape Council)

The interfacial phenomena which occur between the

pressure sensitive adhesive layer and the release coating

are described, together with possible solutions to the

problems which occur.

USA

Accession no.402481

Item 430Meeting Technical & Business Challenges in

Specialised Markets.Proceedings of the ACS Fall 1989

seminar.

Rosemont,Il.,22nd-25th Oct.1989,p.141-52. 6A1

SILICONE SEALANTS AND ADHESIVES FORAEROSPACE/DEFENCE APPLICATIONSBaile M;Fuson S E

DOW CORNING CORP.

(Adhesive & Sealant Council)

A review of the properties and use of silicone sealants

and adhesives for the aerospace industry is presented. It

includes fluorosilicone sealants, sealants for munition

casings, sealants for missiles and aircraft fairing. Silicone

interlayer adhesives for the bonding of substrates used in

canopies and periscopes are also included as well as

general purpose silicone sealants and adhesives which can

be tailored to requirements. Properties of some products

are shown.

USA

Accession no.399401

Item 4313,no.3,1990,p.31/1-31/91

SILICONE RUBBERSTrego B R;Winnan H W

DOW CORNING LTD.; RAPRA TECHNOLOGY

LTD.

Rapra Review Report No.31

A review is presented on silicone rubbers covering basic

formulation and cure chemistry, properties, processing

methods and applications. A literature search from theRapra database on silicone rubbers is included giving

references and abstracts from relevant documents relating

to the report with a subject index. 471 refs.


Accession no.398996


18,No.22,15th May 1989,p.12

FDA STUDYING SILICONE RUBBERCONTRACEPTIVEMoore M

An advisory committee to the FDA is urging the

Administration to approve the use of Norplant. Said to

be as effective as birth control pills and safer to use,

Norplant consists of six silicone rubber capsules

containing levonorgestrel. When implanted under the skin

the capsules provide a woman with a constant miniscule

dose of hormone for up to 5 years. According to the

Population Council, the hormone inhibits ovulation and

prevents sperm from entering the uterus. Results of tests

on 2,470 women are reported.

USA

Accession no.381471


18,No.24,12th June 1989,p.36-41



EFFECT OF CROSSLINK STRUCTURE ONPDMSHalladay J R

LORD CORP.

This detailed review describes studies which examine the

effect of network crosslink distribution on the elastomeric

properties of polymethylsiloxane (PDMS). From the work

by J.E.Mark, the term ‘bimodal networks’ has become

popular, which indicates the crosslinking of long polymer

chains with a large mole fraction of short polymer chains.

The majority of data published has focused on the

elucidation of molecular aspects of rubber elasticity, and

have begun to associate increased tear and tensile strength

with the use of bimodal distribution of polymer chains,

since silicone elastomers are not noted for being over-

endowed with either of these two properties. 17 refs.

USA

Accession no.380899

Item 434Handbook of Pressure Sensitive Adhesive

Technology.2nd edn..

New York,1989,p.601-26. 6A1

SILICONE RELEASE COATINGSJones J D;Peters Y A

DOW CORNING CORP.

Edited by: Satas D


Silicone release coatings are used for bar code labels,

product labels, price tags, care and warning labels, name

tags, display banners, bumper stickers, packaging tapes,

self adhesive wall coverings, floor and carpet tiles and

transfer tapes. Consideration is given to physical

properties, chemistry, types of coating, solvent-borne

release coatings, water-borne systems, solventless silicone

coatings, radiation curable release coatings, coating

evaluation. 12 refs.

USA

Accession no.375985

Item 435Handbook of Pressure Sensitive Adhesive

Technology.2nd edn..

New York,1989,p.508-17. 6A1

SILICONE PRESSURE SENSITIVE ADHESIVESSohieski L A;Tangney T J

DOW CORNING CORP.

Edited by: Satas D


The adhesives are based on a polymer or gum and a

tackifying resin. High molecular weight polydimethyl

siloxane or polydimethyldiphenyl siloxane containing

residual silanol functionality (SiOH) on polymer chain

ends. The resin is a three dimensional silicate structure that

is endcapped with trimethylolsiloxy groups (OSiMe3).

Polycondensation results in a rheologically suitable

material. Cure chemistry after solvent evaporation is

described. The use of primers to obtain adhesion to some

tape backing materials is discussed. Typical properties,

industrial and medical applications are mentioned. 11 refs.

USA

Accession no.375952


17,April 1988,p.279-87

NEW SILICONE FOAM ENHANCES HIGH-PERFORMANCE FABRICSHartley K R

GENERAL ELECTRIC CO.,SILICONE PRODUCTS

DIV.

Details are given of RTF-762 silicone foam for high-

performance fabric applications requiring silicone

properties and light weight. The compound features a

proprietary formulation which is claimed to provide a

level of mechanical strength not previously attainable with

foamed RTV materials.

USA

Accession no.372775

Item 437Adhesives,Sealants,and Coatings for Space and Harsh

Environments.Conference Proceedings.

Denver,Colorado,7-9 April 1987,p.281-91. 63Tr.Sp.

DURABILITY OF SILICONE SEALANTSOwen M J;Klosowski J M

DOW CORNING CORP.

(ACS,Div.of Polymeric Materials Science & Engng.)

The environmental durability of silicone sealants is

reviewed, particular emphasis being placed on PDMS but

with reference to polyphenylmethylsiloxanes and the

fluorosilicone, polytrifluoropropylmethylsiloxanes.

Responses to various environmental stresses, including

those associated with weathering, such as ozone and

temperature extremes, as well as electrical stresses, such

as corona discharge, are discussed. This behaviour is

related to the surface and bulk properties of silicones and

particularly to the low intermolecular forces and high

chain flexibility of the polymer molecules. 27 refs.

USA

Accession no.364141

Item 438European Adhesives & Sealants

5,No.3,Sept.1988,p.3/6

BEWARE THE ACETOXYWoolman R

ADSHEAD RATCLIFFE & CO.LTD.

A review is presented of the many types of silicone

sealants available, their properties, applications and



method of cure. The need for careful selection of the

correct sealant type for a particular application, especially

with regard to volatile products evolved during the curing

process, is emphasised. Particular reference is made to

silicones using acetoxy cure systems. Their irritant factor

and corrosive effect on concrete and metals is outlined.

UK

Accession no.360590

Item 439Synthetic Adhesives and Sealants, Chichester, John

Wiley & Sons, 1987, p.89-111. 6A1

SILICONE ADHESIVES, SEALANTS ANDCOUPLING AGENTSWake W C

CITY UNIVERSITY,LONDON

Edited by: Wake W C

A detailed review is given with particular reference to

chemical rather than physical and engineering aspects of

joints involving silicone polymers and other silicone-

containing compounds. It includes synthesis of monomers

and preparation of polymers, synthesis of silane coupling

agents, crosslinking, primers for silicone adhesives, use

of fine particle fillers in silicone adhesives and sealants,

and durability of silicone adhesives and sealants. 46 refs.

UK

Accession no.359907


65,No.676,March 1988,p.105-10

French

ADHESION OF SILICONE ELASTOMERS:DEVELOPMENT OF AN ON-LINE METHODBarquins M;Pouchelon A

CNRS,LABORATOIRE DE MECANIQUE DES

SURFACES; RHONE-POULENC SA

The adhesion and peel characteristics of viscoelastic

materials are discussed as an introduction to the

development of equipment for the continuous monitoring

of the effects of incorporating compounding ingredients.

Tests were carried out on silicone rubber sheet formed

several days beforehand on a calender. The test machine

can also be used to characterise the tack of thin adhesive

films especially with respect to stick-slip effects. 16 refs.

FRANCE

Accession no.352270


40,No.9,Sept.1987,p.506-8

German

MANUFACTURE WITH SOLID AND LIQUIDSILICONE RUBBERS

Proceedings are reported of the Wurzburg South German

Plastics Federation and the Wurttemburg Engineering

Society meeting in Stuttgart, 21-22 May 1987. A general

description of solid silicone rubber is followed by

suggestions for the design of suitable extruders, infrared

and hot air ovens for crosslinking, and the press moulding

of silicone rubbers. Liquid silicone rubbers are discussed

as an alternative to the solid material and the use of two-

component silicone rubbers is described. Injection

moulding of the two forms is compared and the possibility

of multi-component metering and mixing of the liquid

rubber discussed.

WURTTEMBURG ENGINEERING SOCIETY;

WURZBURG SOUTH GERMAN PLASTICS

FEDERATIONWEST GERMANY

Accession no.348992

Item 442Plaste und Kautschuk

34,No.5,May 1987,p.183-90

German

PHOTOCROSSLINKING OF SILICONESMueller U;Timpe H J;Roesler H

MERSEBURG,TECHNISCHE HOCHSCHULE; VEB

CHEMIEWERK NUENCHRITZ

This is a detailed review on developments in

photocrosslinking of silicones. Principles of

photochemical curing are discussed, types of

photocrosslinkable silicones described and aspects of

application considered. Main application areas for

photocrosslinked silicones are in the production of

printing plates and photoresists. 107 refs.

EAST GERMANY

Accession no.348715

Item 443Pitture e Vernici

63,No.8,Aug.1987,p.13-33

RHODORSILMolteni C

(Italian and English). A detailed account is presented of

the chemistry and technical properties of silicone

polymers in building preservation and restoration. 21 refs.

RHONE-POULENC ITALIA SPAITALY

Accession no.348044

Item 444132nd Meeting,Fall 1987.Preprints.

Cleveland,Ohio,Oct.6-9,1987,Paper 9

SILICONE RUBBER, ITS DEVELOPMENT ANDTECHNOLOGICAL PROGRESSPolmanteer K E

(ACS,Rubber Div.)

The development and technological progress of silicone

rubber since it first became commercially available within



the USA in 1944 from both the Dow Corning Corp. and

the General Electric Co. are discussed. The key advances

in tensile strength, room temp. vulcanisation, copolymers,

new silicas, water-based compounds, high tear/tough

compounds, liquid rubber, the Silastic Compounding

System, cost/performance and medical grade rubber,

responsible for the technological progress of silicone

rubber are chronologically traced from 1944 to 1987.

Finally, the combined silicone rubber technology as it

commercially exists in 1987 is discussed. 33 refs.

DOW CORNING CORP.; GENERAL ELECTRIC CO.

USA

Accession no.344588


119,No.8,Aug.1987,p.20-2

TECHNICAL INNOVATIONS ENHANCECOMMERCIAL VALUE OF SILICONE RUBBERToub M R

GENERAL ELECTRIC CO.

The article looks at the value of silicone rubber in a

diversified elastomer market. Silicone sales trends are

examined with respect to physical properties and

application areas such as the automotive, aerospace, wire,

cable and medical markets. 4 refs.

GENERAL ELECTRIC CO.,SILICONE PRODUCTS

DIV.

USA

Accession no.341536

Item 446High Performance Polymers: Their Origin and

Development.Proceedings of the Symposium held New

York,15-18 April 1986.

New York,NY,Elsevier Science Publishing

Co.Inc.,1986,p.381-8. 63E

HISTORY OF SILICONE ELASTOMERSFearon F W G

DOW CORNING CORP.

Edited by: Seymour R B;Kirshenbaum G S

(ACS)

Key discoveries in the development of silicone elastomer

technology were reviewed with comment on monomer

(chlorosilanes, siloxanes) synthesis and polymerisation

(thermal condensation, ring-opening, emulsion),

reinforcement (fumed silica fillers, copolymerisation,

block copolymers, blends, IPN’s), crosslinking

(peroxides, reactive group incorporation, RTV systems,

one- and two-component systems), processing and

fabrication, and properties. Composition and structural

features responsible for the characteristic properties were

discussed and related to applications. 27 refs.

USA

Accession no.330649

Item 447Cyclic Polymers.

Barking,Elsevier Applied Science Publishers

Ltd.,1986,p.85-133. 6116

PREPARATION OF CYCLIC POLYSILOXANESWright P V;Beevers M S

ASTON,UNIVERSITY; SHEFFIELD,UNIVERSITY

Edited by: Semlyen J A

(York,University)

Essential procedures used in preparing and analysing the

products of cyclisation reactions and in separating

fractions of cyclic siloxane material were described in

this review. The formation of siloxane rings in equilibrates

and in irreversible processes, the critical concentration

in polysiloxane equilibrates (theory,influence of

substituents on cyclic formation, thermodynamic

influences on equilibrium position, distribution and

configurational isomers of cyclic phenylmethylsiloxanes),

preparation of siloxane cyclic residues (reaction

quenching, fractionation), analytical GPC (cyclic and

linear distributions within macrocyclic residues),

preparative GPC, and ring-chain equilibration of siloxane

copolymers (polytetramethyloxadisilacycloheptane,

copolymers of polysiloxane and PS segments) were

discussed with relevant equations. 75 refs.

UK

Accession no.329122

Item 448Applied Polymer Science 2nd Edn.,ACS Symposium

Series 285.

Washington D.C.,1985,p.1117-40. 012

RESINS AND ADDITIVES CONTAININGSILICONThames S F

SOUTHERN MISSISSIPPI,UNIVERSITY

Edited by: Tess R W;Poehlein G W

(ACS,Div.of Polymeric Materials Science & Engng.)

Silicon and carbon compounds were compared by

considering inductive effects and (p-d) pi bonding, bond

strengths (silicon bonds to halogen, carbon including

double bond, hydrogen, oxygen and nitrogen). The

characteristics of silicone polymers (enhanced thermal

stability, higher water repellency, incompatibility with

organic materials) and their resultant applications, silicon-

containing polymers (high-temperature coatings, blends),

pigmentation, silicones as water repellents, and silicones

as additives (paint formulation, coupling agents,

incorporation into main chain to lower Tg of polyamides

and polyimides). 29 refs.

USA

Accession no.320195


39,No.1,Jan.1986,p.33-6



German

SILICON RUBBERS - A SURVEYBittera J

WACKER CHEMIE GMBH

A report on silicon rubbers is given which divides the

materials into different crosslinking categories. These are:

one- and two-component RTV types; addition

crosslinkable HTV types (liquid, dispersion and solid

rubbers); peroxide crosslinkable rubbers; and irradiation

crosslinkable HTV types. Properties and application areas

for these rubbers are indicated. (DKG Conference,

Hanover,March 1985).

WEST GERMANY

Accession no.317150


29,No.6,31st May 1986,p.8-11

SILICONE SEALANT TECHNOLOGY,MARKETS CONTINUE TO GROWElias M

SEALANTS TREMCO INC.

An overview of one-component silicone sealant

technology and applications is presented, with

information being provided on the chemistry of these

sealants, defining the desired property profile,

compounding and end-use applications. Basic high,

medium and low modulus formulations containing

acetoxy, oxime and amine crosslinkers are tabulated

along with suitable fillers. 5 refs.

USA

Accession no.315239

Item 451Advances in Polymer Science

No.68/69,1985,p.216-25

POLYSILOXANESPenczek S;Kubisa P;Matyjaszewski K

The literature on the synthesis of polysiloxanes by cationic

ring-opening polymerisation is reviewed. Aspects covered

include the synthesis of polydimethylsiloxanes from

octamethylcyclotetrasiloxane, telomerisation,

polymerisation of alkylhydrosiloxanes, macrocyclisation,

and the polymerisation mechanism. 35 refs.

POLAND

Accession no.304786

Item 452Manufacturing Chemist

56,No.11,Nov.1985,p.59

COMPARING SILICONE COST-EFFECTIVENESSAlexander P

A review is given of silicone-based cosmetic raw

materials, including polyether polysiloxanes, with an

examination of their cost-effectiveness, particularly as

functional, rather than fashionable, constituents of hair

care preparations.

UK

Accession no.301333

Item 453Plastics for Electronics.

Barking,Elsevier Applied Science Publishers

Ltd.,1985,pp.67-97. 6E

SILICONE PROTECTIVE ENCAPSULANTS ANDCOATINGS FOR ELECTRONIC COMPONENTSAND CIRCUITSDavis J H

DOW CORNING LTD.

Edited by: Goosey M T

(Dynachem Corp.)

Silicones were defined and their physical properties

(thermal and oxidative stabilities, stability in physical and

dielectric characteristics with temperature, surface,

handling, fire resistance, combustion products, chemical

purity, low water absorption), production and typical

products were indicated before reviewing the different

types of silicone and their application in electronics. One-

and two-component elastomeric sealants and

encapsulants, conformal coatings and impregnating resins,

transfer moulding compounds, performance, high purity

coatings and adhesives, insulating and constructional

materials, wire and cables, silicone aids in electronic

production, and future developments were discussed. 20

refs.

UK; USA

Accession no.300427

Subject Index

© Copyright 2001 Rapra Technology Limited 153

Subject Index

AABRASION RESISTANCE, 14 34

42 119 145 161 218 233 306313 334 347 382

ABS, 14 237 238ACCELERATED TEST, 269 338

394 395ACCELERATOR, 304 329 331ACID RESISTANCE, 74 249 293ACOUSTIC INSULATION, 367

381ACRYLIC ELASTOMER, 287 291

383ACRYLIC RESIN, 14 247 286 379

390 422ACTIVATION ENERGY, 200 246

312ACTIVATOR, 304ADDITION CURING, 163 165ADDITION POLYMERISATION,

64 129 143 213 423ADDITION REACTION, 17 34 41

65 89 250 261 263ADDITIVE, 14 25 26 37 38 58 81

92 98 103 105 129 131 138 159167 181 185 187 188 194 200202 218 219 222 237 238 246248 249 250 292 293 295 304311 312 325 331 342 346 363372 379 392 421 440 448

ADHESION, 25 26 59 60 64 65 7789 90 97 105 115 125 136 138150 168 186 206 229 236 238250 261 295 313 338 370 377380 381 390 392 394 395 415423 429 440 448

ADHESION PROMOTER, 38 81201 415

ADHESIVE, 40 52 75 121 126 140147 238 244 338 368 372 377380 387 396 417 430 434 435439 440 453

ADHESIVE TAPE, 96 380 429ADSORPTION, 32 70 300AEROSPACE APPLICATION, 7

15 72 168 185 219 255 258 319336 343 363 377 430 431 445

AESTHETIC, 14 237AGEING, 20 129 131 138 202 205

217 219 248 249 250 269 280287 291 313 343 363 394

AIR BAG, 25 42 63 77 121 123126 144 159 161 255 313 404

AIR CONDITIONING, 319

AIR CURING, 379AIR ENTRAPMENT, 414AIR EVACUATION, 227AIR INTAKE SYSTEM, 64AIR POLLUTION, 137ALKOXYSILANE, 10 211 250ALLERGY, 30 100ALUMINIUM FOIL, 303 353ALUMINIUM HYDROXIDE, 17

41 109 371ALUMINIUM OXIDE, 10 162AMINOPROPYLTRIETHOXYSILANE,

274AMINOSILANE, 408AMMUNITION, 295ANALYSIS, 28 69 92 94 200 208

217 225 246 253 292 294 307310 318 325 326 342 347 447

ANCILLARY EQUIPMENT, 2 359ANIMAL TESTING, 217ANTI-ADHESIVE PROPERTIES,

26 138ANTI-FOAMING AGENT, 140

304 368ANTIFOULING, 43ANTI-SCORCH AGENT, 53ANTI-SLIP PROPERTIES, 25ANTIOXIDANT, 293 304ANTISTATIC PROPERTIES, 218ARAMID FIBRE, 303ARC RESISTANCE, 137 219ARCHITECTURAL

APPLICATION, 138ARMCHAIR, 14ART, 138 403ARTIFICIAL BONE, 4 373 409ARTIFICIAL BREAST, 26 69 111

122 152 195 199 208 216 217242 259 279 283 296 318 350389

ARTIFICIAL HIP, 344ARTIFICIAL JOINT, 373ARTIFICIAL LIMB, 360ARTIFICIAL MUSCLE, 178ARTIFICIAL OESOPHAGUS, 361ARTIFICIAL ROCK, 62ARTIFICIAL SKIN, 325ARTIFICIAL TEETH, 14ARTIFICIAL TENDON, 174ASSEMBLY, 91 121AUTOCLAVE, 131 341AUTOIMMUNE DISEASE, 298

299AUTOMATION, 2 104 121 126

150 193 234 235 243 248 256

326 374 385 393AUTOMOTIVE APPLICATION, 6

7 11 13 15 25 26 27 35 40 42 4854 60 63 64 72 77 79 82 89 103105 114 118 121 123 124 126144 150 159 161 163 166 168175 179 181 185 191 193 194196 202 204 215 219 226 235238 243 250 255 257 258 263269 273 275 284 287 290 291294 303 311 313 321 325 327339 349 353 355 363 364 367368 375 377 378 380 381 385391 392 404 405 408 412 413427 431 445

AXLE, 38

BBABY FEED BOTTLE, 37 224

304 364BACTERIA, 236 268 366BAG, 352BALLOON, 30 176BALLOON CATHETER, 29BARIUM, 384BARREL, 179BARREL TEMPERATURE, 200

227 229 246BARRIER, 168 331 352 394BATH, 238BELLOWS, 250BELT, 306 313BENCH, 347BENDING STRENGTH, 4BENZOYL PEROXIDE, 33 112BETA RAY, 239BETA-ESTRADIOL, 340BIDET, 422BINDER, 187 403 426BIOCHEMISTRY, 217 253 298BIOCOMPATIBILITY, 14 23 24

25 30 31 39 57 61 68 71 87 91100 128 131 133 134 135 172173 174 186 197 199 203 206236 239 255 265 266 268 278279 280 281 283 296 315 384389 399 407 409 416

BIODEGRADATION, 134 216 217283 296 298 340 366

BIOLOGICAL ATTACK, 370 389BIOMATERIAL, 23 24 31 61 71

80 87 128 133 135 172 174 186198 199 206 239 247 278 280281 283 286 296 297 298 300

Subject Index


308 314 315 361 370 399BIOMEDICAL APPLICATION, 21

30 31 39 131 188 197 217 283389 399

BLEED-THROUGH, 203BLEEDING, 218 219BLEND, 17 41 68 118 200 237 238

276 328 446 448BLOCKING RESISTANCE, 103BLOOD CONTACT

APPLICATION, 131 158 296BLOWING AGENT, 88 136BOND STRENGTH, 11 59 60 125

415 448BONDING, 9 59 64 89 125 202

211 218 295 338 392 421BONDING AGENT, 52 147 295BOROSILICATE, 295BOTTLE, 37 224BREAK RESISTANCE, 189BREAKING STRENGTH, 7BREATHABILITY, 168BRIDGE, 72BUILDING APPLICATION, 26 40

72 76 138 140 187 215 226 238324 352 362 363 365 394 395404 422 423 431 438 443

BUMPER, 159BURST STRENGTH, 428BUSHING, 41 229 367BUSINESS MACHINE, 194 219

234 255

CC-FRAME, 150CABLE, 6 11 20 26 33 106 112

159 185 219 249 250 303 311313 332 343 352 353 363 371392 445 453

CABLE CONNECTOR, 15 185CABLE SUPPORT, 319CALCIUM CARBONATE, 1 256

408CALORIMETRY, 221CAP, 204 222CAPACITY, 226CAPILLARY RHEOMETRY, 246

292 310CAPSULE, 239 323 432CAR, 25 26 105 150 159 185 193

194 202 219 238 250 263 269294 303 311 313 325 353 363380 385 392 405

CARBON BLACK, 46 105 127218 250

CARBON DIOXIDE, 303 419CARBON FIBRE, 19 165 295 336

400CARBORANE SILOXANE

POLYMER, 371CARCINOGEN, 111 208 242 304

350 389 399CASING, 194CAST, 45 107 141 182 393CASTING, 14 26 175 194 237 295

331 357 393CATALYST, 5 17 38 81 88 95 97

157 201 202 232 251 256 400408 434

CATALYTIC CONVERTER, 219CATHETER, 24 29 100 147 156

163 176 206 268 311 370 384CAVITY PRESSURE, 104CELL CULTURE, 23 186 296CELLULAR MATERIAL, 14 88

94 99 136 192 238 285 306 352381 387 389 392 394 436

CERAMIC, 13 155 164 187 312338 352 388 422 426

CERAMIC FIBRE, 426CEREBROSPINAL FLUID

SHUNT, 221CERTIFICATION, 234 243 262

263 353CHAIN SCISSION, 131 200 363CHAIR, 14CHALK, 408CHARACTERISATION, 51 145

225 239 316CHEMICAL MODIFICATION, 3

21 56 65 75 92 103 131 202217 301 406

CHEMICAL PROPERTIES, 7 1114 20 26 48 65 67 69 74 77 8191 103 118 119 131 148 159168 169 185 202 218 240 417425 426 439

CHEMICAL RECYCLING, 263303 311

CHEMICAL RESISTANCE, 7 1114 20 26 35 48 60 65 67 74 7781 91 103 118 119 131 148 159168 169 185 191 202 218 219240 249 293 295 313 336 363367 377 380 381 385 394 395407 431

CHEMICAL STRUCTURE, 5 8 2126 36 65 72 91 112 131 135 138177 185 187 200 212 219 255394 426 450

CHIP, 75CHLOROSILANE, 328 363 446CHONDROITIN SULFATE, 283CHROMATOGRAPHY, 101 200

225

CLAMP FORCE, 2 150 179 229234 235 248 326 341 374 385

CLAY, 110 331CLEAN ROOM, 229 262 408CLOSED MOULD, 295 311CLOTHING, 25 168 263 303 311

313 353CO-ROTATING EXTRUDER, 246

309COATED FABRIC, 14 25 42 63

161 168 255 263 303 313 353436

COATED PAPER, 25 346COATING, 3 6 25 40 42 43 44 59

72 73 77 103 115 137 139 161187 233 237 238 250 263 274289 293 295 303 313 319 331346 350 353 364 367 370 377378 379 380 382 389 390 394404 423 434 448 453

COCHLEAR IMPLANT, 265COEFFICIENT OF FRICTION,

103 218COEXTRUSION, 35 100COINJECTION MOULDING, 26

60 102 119 173 179 185 261COLD CURING, 14 26 363COLD RUNNER, 2 9 102 104 119

150 173 193 204 207 227 235248 273 282 311 385

COLLAGEN, 80 217 283 293 361COLORABILITY, 219COLORANT, 229 237COLOUR, 2 14 131 157 218 219

229 237 248 295 302 311 331408 422

COMBUSTION, 185 263 352 453COMMERCIAL INFORMATION,

40 60 91 120 126 136 179 223306 369 414 426

COMPATIBILITY, 15 21 102 103290 377

COMPETITIVENESS, 381COMPLEMENT ACTIVATION,

268COMPOSITE, 14 19 33 50 55 80

89 127 142 149 150 153 183196 210 238 240 245 246 251263 275 295 303 317 319 323335 336 337 353 360 374 382385 391 400 410 417 426 428

COMPOUND, 26 202 249 269 292342 417

COMPOUNDING, 14 26 40 77137 185 189 200 202 248 250309 311 342 363 392 424 450

COMPRESSION MOULDING, 1456 77 91 163 185 200 234 269

Subject Index


342 369COMPRESSION PROPERTIES,

14 294 383COMPRESSION SET, 65 77 95 97

154 166 179 202 218 219 248249 250 269 291 342 383 441

COMPRESSION STRESSRELAXATION, 219 269 367383

COMPUTER AIDED DESIGN, 2864 83 141 180 237 238 294 310405

COMPUTER AIDEDMANUFACTURE, 405

COMPUTER APPLICATION, 52243

COMPUTER CONTROL, 104 193360 385 393

COMPUTER SIMULATION, 4764 105 310

CONCRETE, 352 422CONDENSATION

POLYMERISATION, 85 143191 328 423 435 446

CONDUCTIVE COATING, 289CONDUCTIVE RUBBER, 218

250 263 275 289 303 311 312336 353

CONFERENCE, 104 105 138 200202 217 218 219 235 246 269283 294 295 307 309 310 325326 331 342 383 408 441

CONNECTOR, 27 60 106 114 235400

CONSERVATION APPLICATION,403

CONSTRUCTION, 352CONSUMPTION, 40 77 179 185

226 255 368 376CONTACT ANGLE, 20 21 65 97

167 205 206 236 239CONTACT LENS, 21 264 419CONTAMINATION, 20 109 137

262 407CONTRACEPTIVE, 323 397 411

432CONTROL, 2 104 119 132 179

193 234 235 273 385 393CONTROLLED RELEASE, 156

188 221 267 301 340 372 432CONVEYOR BELT, 313COOLANT, 11 166COOLER HOSE, 166 219 392COOLING, 104 105 179 193 235

273 311 319 413COOLING TIME, 105CORE-PULLING, 326CORK SUBSTITUTE, 219

CORNEA, 21CORROSION RESISTANCE, 43

74 159 240 295 438COSMETICS, 110 213 293 318COST, 6 18 99 102 119 150 161

179 180 192 196 218 224 226227 234 235 237 248 260 282342 352 377 381 385 393 444445

COUNTER-ROTATINGEXTRUDER, 309

CRACK, 379 386 428CRACKING, 202 292 295 347 386

428CRANKSHAFT, 219CRASH SIMULATOR, 325CREASE RESISTANCE, 303CROSSLINK, 1 201 250 263 293

303 304 311 353 359 379 395433 439 446 449

CROSSLINK DENSITY, 51 101188 200 213 218 269 283 342356

CROSSLINKING, 18 21 39 46 5154 65 68 78 81 89 131 157 163165 173 197 200 202 209 218227 229 328 395 439 446 449

CUP, 229CURE RATE, 18 26 47 51 64 65

105 200 202 241 248 250 256342 408

CURE TIME, 2 6 26 60 129 131138 150 185 200 202 248 250263 303 311 325 353

CURING, 1 3 6 8 10 12 14 15 2526 34 40 41 47 48 49 59 65 6875 78 90 91 103 107 112 119120 124 131 132 135 138 152153 154 159 163 165 185 194200 202 235 238 244 263 270271 288 290 292 295 307 310320 325 331 339 342 346 348363 377 379 380 383 385 393395 408 411 414 431 434 435438 441 450

CURING AGENT, 1 25 26 38 3958 77 81 88 94 110 113 131 138159 162 185 188 200 202 218233 249 250 285 292 295 304331 342 363 392 396 438 446449 450

CURING SYSTEM, 120 219CURING TEMPERATURE, 17 26

47 60 64 105 120 131 138 185200 248 250 263 303 304 311325 342 353

CUSHION, 228CUSTOM MOULDING, 344

CYCLE TIME, 60 64 65 105 150173 179 185 193 224 229 234235 248 250 331 342

CYTOTOXICITY, 23 25 61 131143

DDAMP-PROOFING, 187DECORATION, 238 349 355DEFECT, 18 248 292 331 366DEFENCE APPLICATION, 295

336DEFORMATION, 105 246 247 283

292 294 310 344DEGRADATION, 4 20 129 131

138 202 205 216 217 219 240258 283 338 347 366 367 380389 394 407

DEMAND, 7 35 40 118 181 376DEMOULDING, 2 49 104 185 193

204 227 248 269 305 326 331385

DENSITY, 65 94 167 192 249 292336 338 352 408

DENTAL APPLICATION, 14 2653 143 240 247 281 286 382398

DEODORANT, 110DESIGN, 9 18 28 29 49 67 105 119

141 158 161 180 189 204 207220 234 237 238 243 264 294331 338 375 405

DEVOLATILISATION, 185 246309

DIAGNOSTIC APPLICATION, 22DIALYSIS, 263 303DIAPHRAGM, 250DIATOMACEOUS EARTH, 441DIE, 73 75 160 238 260 292 309

310 359DIE SWELL, 220 310DIELECTRIC CONSTANT, 3 5

380DIELECTRIC LOSS, 312 371DIELECTRIC PROPERTIES, 131

185 249 293 311 312 363 371380 453

DIFFERENTIAL THERMALANALYSIS, 92 239 245 402420

DIFFUSION, 15 21 82 98 142 188195 267 301 308 340 389

DIMENSIONAL STABILITY, 130138 248 263 272 281 303 305311 331 348 353 398

DIPPING, 304 357DIRECT EXTRUSION, 327

Subject Index


DIRECT INJECTION, 173 193DIRECTIVE, 262DISC DRIVE, 306DISPERSION, 74 76 276 284 293

357 449DISPLAY DEVICE, 289DIVING MASK, 227DO-IT-YOURSELF, 226DOMESTIC EQUIPMENT, 26 54

79 194 226 238 368 391DOOR, 88 238 362 422DOOR SEAL, 219DOPANT, 312 379DOSING, 104 227DRUG DELIVERY, 98 100 184

188 267 271 301DUAL HARDNESS, 119 179DUCT, 352DUMMY, 118 192 250 263 303

304DURABILITY, 68 243 269 367

381 395 412 417 437 439DYNAMIC MECHANICAL

PROPERTIES, 310 428

EEARPLUG, 263 303ECONOMIC INFORMATION, 7

35 40 60 77 89 99 103 118 148161 179 181 185 226 235 255257 376 377 445

ELASTICITY, 4 5 18 21 25 84 90131 138 159 167 185 237 271292 294 311 379 395 433

ELECTRICAL APPLICATION, 2026 33 41 55 59 72 73 77 84 96106 112 114 159 194 209 215219 222 238 249 250 255 257289 290 311 313 333 334 343353 354 363 405 431 445 453

ELECTRICAL CONDUCTIVITY,67 127 165 218 229 250 263275 289 303 311 312 353

ELECTRICAL CONNECTOR, 2760 211 219 311

ELECTRICAL INSULATION, 3 517 20 26 41 67 73 102 109 112118 137 159 163 173 181 189219 249 255 293 313 332 343363 380 381 388 390

ELECTRICAL PROPERTIES, 3 517 20 26 41 56 65 73 78 91 109112 118 127 131 148 159 163173 179 181 185 218 219 222235 248 249 250 263 274 275290 293 303 311 312 348 353

363 371 377 380 425 431 436437

ELECTROLUMINESCENCE, 36209 212 354

ELECTROMAGNETIC SHIELD,336

ELECTRON BEAM, 346ELECTRON BEAM CURING, 8

363 372 434ELECTRONIC APPLICATION, 1

3 5 7 8 36 52 54 59 72 74 79 8486 116 194 232 238 244 250257 263 270 274 277 290 303311 329 336 339 348 353 364369 377 378 380 390 391 400453

ELONGATION, 63 65 68 90 129131 157 167 200 202 218 219228 235 248 249 291 295 342345 408 441

ENCAPSULATION, 74 184 270274 293 329 391 400 417 453

ENDOSCOPE, 100ENERGY CONSUMPTION, 13 81

173 200 248 342ENGINE, 13 159 219 223 319 321

327 335ENGINE MOUNTING, 11ENGINE OIL, 291ENGINEERING APPLICATION,

14 65 238 439ENVIRONMENT, 103 263 282

303 353 377ENVIRONMENTAL

RESISTANCE, 137 389 417EPOXY RESIN, 12 19 138 305

328 329 331 351 390 415ESTRADIOL, 340ETCHING, 164 295 312ETHYLENE OXIDE, 131 239ETHYLENE-PROPYLENE-

DIENE TERPOLYMER, 18 20109 219 367 408

EXHAUST SYSTEM, 11 60EXPOSURE LIMIT, 208 304EXPOSURE TIME, 131 202 208

217 219EXTRACTION, 69 200 271 304EXTRUDATE, 292 310 401EXTRUDER, 73 160 246 309 310

359 411EXTRUSION, 7 14 26 49 54 85 91

101 108 151 159 160 171 185200 201 230 238 246 249 276285 292 309 310 321 327 359363 401 413 431 441

EXTRUSION MOULDING, 162

EYE DAMAGE, 21 80

FFABRIC, 14 25 42 63 161 168 313

364 378FABRIC REINFORCED, 319FABRICATION, 75 91 141 271

354 425FACE MASK, 325FAILURE, 66 105 111 122 189 295

327 366FAST CURING, 26FATIGUE, 28 219 252FEEDING, 104 160 201 248 295

374FIBROBLAST, 186 198 239 283FILLER, 14 25 26 37 38 41 46 58

64 65 76 81 85 92 105 109 113127 131 137 138 162 165 167183 185 189 191 201 202 218219 222 238 246 250 255 256276 292 295 304 325 329 331363 371 384 391 392 394 439444 446 450

FILM, 3 8 32 39 42 44 168 206 236238 300 312 319 377 394 399440

FINISHING, 181 237 385FINITE ELEMENT ANALYSIS,

28 246 294 310 326FIREPLACE, 422FLAME RETARDANT, 33 219

222 232 238 276 311 352 371381 394 453

FLAMMABILITY, 25 26 185 192215 219 222 238 248 249 263276 303 311 313 319 342 353362 363 371 394 407 436 453

FLASH, 104 227 400FLASH REMOVAL, 269 385 441FLASHLESS, 2 185 202 234 248

311 326FLEXIBILITY, 15 25 64 65 105

118 194 219 227 229 237 248249 313 319 343 348 352 364373 409 423

FLEXURAL PROPERTIES, 56105 190 237

FLOW, 18 58 132 200 220 236 246292 307 309 310 331 342

FLOW RATE, 179 200 246 271307 309

FLUE, 77FLUID, 38 45 202 211 246 271

293FLUID RESISTANCE, 202FLUOROELASTOMER, 34 77

Subject Index


127 219 249 258FLUOROSILICONE RUBBER, 77

127 148 185 238 248 294 336377 430 437

FOAM, 14 88 94 136 192 238 251285 318 319 350 352 381 387389 392 394 436

FOAM-IN-PLACE, 99 136FOGGING, 303FOOD-CONTACT

APPLICATION, 25 26 54 185215 218 229 255 262 304 313407 408

FOOTWEAR, 228 345 408FORM-IN-PLACE, 339FORMULATION, 46 90 103 166

189 222 241 264 287 340 381395 430 431 444 448 450

FRACTURE MORPHOLOGY, 20133 186 208 231

FREE RADICAL, 75 131 250FRICTION PROPERTIES, 35 103

145 218FUEL HOSE, 77FUEL RESISTANCE, 77 148 159FUMED SILICA, 92 219 251 446FURNITURE, 14 103

GGAMMA-IRRADIATION, 131GAS INJECTION MOULDING,

18 102 132 238 285GAS PERMEABILITY, 21 138

264 313 418GASKET, 13 35 38 48 81 95 118

136 150 181 196 202 219 223256 269 285 291 294 306 324336 339 367 368 383 392 412

GATE, 104 119 227 229 307 311331

GEL, 21 26 27 66 84 101 110 111114 122 151 159 178 188 195199 203 213 217 218 238 270274 296 318 322 358 380 387389

GLASS, 12 14 138 334 394 422GLASS FIBRE, 14 62 150 238 364

374 379 385 400 417GLASS TRANSITION

TEMPERATURE, 131 245 316329 363 379 380 400 443 448

GLAUCOMA, 57GLAZING, 138 226 324 368 394

408GLOSS, 14 103GRANULE, 26 304GREASE RESISTANCE, 249

GREEN STRENGTH, 160 295GRINDING, 200 218GROMMET, 219 294 380GROWTH RATE, 7 40 48 77 102

103 118 185 226 336 368GUN, 305

HHAIR CONDITIONER, 452HARDNESS, 14 26 65 90 95 105

107 114 129 131 138 157 160179 182 185 194 202 207 218219 227 229 235 248 249 263291 292 294 303 311 331 353364 383 393 408

HEAD REST, 14HEALTH HAZARD, 14 25 66 111

131 143 185 192 203 208 210259 271 318 322 323 350 389390 407

HEART VALVE, 28 128HEAT AGEING, 65 177 202 219

249 269 383 392HEAT CURING, 14 15 25 26 40 48

78 120 131 138 159 163 185235 238 244 255 292 310 313363 368 379 383 392

HEAT INSULATION, 55 118HEAT RESISTANCE, 7 11 14 15

25 26 46 48 50 60 64 77 90 105118 121 126 129 131 138 148159 169 179 185 194 202 218219 227 229 235 248 250 263269 290 291 293 295 303 311313 329 343 353 363 380 385391 392 412 422 437 445

HEAT SHIELD, 303 313HEATER HOSE, 392HERMETIC SEAL, 121 126 270

293HIGH-PERFORMANCE, 82 303

377 378HIGH TEMPERATURE, 196 249

269 412 413 448 449HIGH VOLTAGE APPLICATION,

41 189 219 222HINGE, 331 373HIP JOINT, 344HISTOLOGY, 172 266 361HISTORY, 90 139 140 148 363 376

446HOLDING PRESSURE, 64 105HOLDING TIME, 227 229HOLLOW ARTICLE, 18HOSE, 18 77 123 149 159 166 171

219 319 335 368 392 413HOT CURING, 14 15 25 26 40 48

78 120 131 138 159 163 185235 238 441

HOT MELT ADHESIVE, 377HOUSEWARES, 54 79HYDRAULIC, 150 248 311 326

385HYDROGEL, 21 264 370HYDROLYSIS, 5 138 177 191 205

216 217 328 363 389 439HYDROLYTIC STABILITY, 21

185 205HYDROPHILIC, 21 184 188 264

419 423HYDROPHOBIC, 20 21 89 137

138 188 189 218 236 293 389423

HYDROSILYLATION, 3 56 65 75202 363 396

HYDROTHERMAL STABILITY,338 415

HYPODERMIC SYRINGE, 115

IIMMERSION, 202 269 379 383IMMUNOLOGY, 22 298 299 300IMPACT PROPERTIES, 14 25 56

189 276 325IMPLANT, 4 28 31 57 66 69 80 87

111 122 131 172 195 198 199203 210 216 217 229 239 266279 280 283 296 297 298 299300 314 315 322 323 338 340350 358 361 366 373 384 389397 399 409 432

IMPRESSION MOULD, 53IN-VITRO, 57 217 268 278 296

298 389IN-VIVO, 69 87 143 217 296 298

389INDOMETHACIN, 267INDUSTRIAL APPLICATION, 72

140 148 352 377INDUSTRIAL ROBOT, 2 150 193

326INERT, 7 68 300INFLAMMATION, 268 297INFLATABLE, 25 176 358INFLATION PRESSURE, 294INHIBITOR, 157 331INJECTION COMPRESSION

MOULDING, 14INJECTION MOULD, 2 104 105

150 185 193 248 250 263 265295 303 304 307 311 325 326342 353 363 385 391 405

INJECTION MOULDING, 2 7 911 14 15 18 26 47 49 60 64 65

Subject Index


77 79 83 89 91 95 97 102 104105 118 125 129 132 150 154157 159 163 165 169 173 179180 181 185 190 193 202 204207 219 223 224 229 234 235238 243 251 257 260 261 282290 329 344 348 349 355 364378 385 414 441

INJECTION MOULDINGMACHINE, 2 9 67 79 102 119193 223 227 260 273 341 374

INJECTION PRESSURE, 65 173202 229 248 250 305 326

INJECTION TRANSFERMOULD, 295

INJECTION UNIT, 2 119 150 193235 273

INSERT, 2 150 194 295 331INSERT MOULD, 11 60 64 65 89

105 150 238 248 250 295INSERT MOULDING, 2 26 150

185 229 369INSOLE, 228 345INSULATION, 20 26 41 55 96 118

224 334 453INTEGRATED CIRCUIT, 8 232

270 329 380INTERFACIAL ADHESION, 105

429INTERNAL COMBUSTION

ENGINE, 13INTRAOCULAR LENS, 16IRON OXIDE, 38 81 129 157 219IRRITANT, 131

KKEY, 116KEYBOARD, 116 238 243 250

263 303 311 353KEYBOARD MAT, 234 243KEYPAD, 1 52 163 179 219 224

303 369

LLACQUER, 390LAMINATE, 65 349 355 381 400

417LAPAROSCOPE, 100LARGE-COMPONENT, 67 193LATEX, 7 100 102 293 304LAWSUIT, 210 322 323LEAD TIME, 60 83 341LEAKAGE, 137 195 269 274 298LEGISLATION, 103 111 131 242

262 304LENS, 16 21 238 419

LEVONORGESTREL, 323 397432

LIFETIME PREDICTION, 271LIGHT DEGRADATION, 26 312

363 394 437LIGHT-EMITTING DIODE, 36

212 354LIGHT RESISTANCE, 26 185 248

250 311 380LIGHT TRANSMISSION, 107 116

182LIGHTING APPLICATION, 238LIGHTNING CONDUCTOR, 67LIMITING OXYGEN INDEX, 249LINING, 149 228LIPID, 21 195 217LIQUID CASTING, 295LIQUID INJECTION

MOULDING, 7 15 65 89 91 9597 102 104 159 179 180 185193 202 219 223 235 238 243248 250 263 282 295 303 304311 326 341 342 353 363 368369 385 405

LIQUID POLYMER, 95 97 132154 207 214 284 339 355 400

LIQUID RUBBER, 11 15 18 26 4047 49 51 54 60 64 65 67 77 7989 102 104 105 118 119 132138 157 159 161 163 173 179182 185 193 202 204 219 224227 229 234 238 241 243 248250 255 257 260 263 273 282295 303 304 311 313 326 342348 349 353 363 369 374 378385 387 405 414 441 444 449

LITHOGRAPHY, 71 141 312LONG-TERM, 20 21 34 45 274LOW TEMPERATURE CURING,

377LOW TEMPERATURE

PROPERTIES, 15 77 118 179219 227 235 248 249 287 291313 380 422

LOW TEMPERATURERESISTANCE, 219

LOW VISCOSITY, 104 138 204227 248 250 257 348

LUBRICANT, 24 38 82 115 159202 293 363 392 423

LUMINESCENCE, 36 209

MMACHINERY, 2 9 14 25 51 62 67

73 79 102 104 105 119 150 160179 182 185 193 194 223 227229 234 235 237 246 248 250

260 305 307 309 310 311 320325 326 327 331 342 355 359385 393 405

MACHINING, 237MACROPHAGE, 217 239 278 389MAGNESIUM OXIDE, 38 81 219MAGNETIC PROPERTIES, 217

293MAGNETIC RESONANCE

IMAGING, 174MANDREL, 34 310MANIFOLD, 326 367MANNEQUIN, 192 325MARINE APPLICATION, 72MARKET, 99 161 185 259 329 368

377 413 445MARKET GROWTH, 181MARKET SHARE, 40 77 89 103

179 226 235 255 336 368MASK, 325MASTERBATCH, 26 131MATERIAL REPLACEMENT, 7

30 42 94 100 102 116 134 156224 234 242 243 282 330 404409 410

MATERIALS SELECTION, 91146 149 168 352

MAXILLO-FACIAL SURGERY,167

MECHANICAL PART, 150 159185 202 219 250 255 263 269293 294 295 303 311 353 363380 383 385 392

MECHANICAL PROPERTIES, 47 14 15 17 18 21 24 25 26 2834 35 42 50 53 56 63 64 65 6977 78 84 89 90 91 92 93 94 9597 101 103 105 106 108 114118 119 124 125 129 130 131134 138 145 154 157 159 160161 166 167 174 179 184 185189 190 194 200 202 205 207214 218 219 221 227 228 229233 235 237 241 243 246 247248 249 250 252 257 263 265269 276 283 286 287 291 292294 295 303 304 306 307 310311 312 313 319 325 329 331334 342 343 345 347 348 352353 363 364 367 373 375 379380 381 382 383 389 392 393394 395 398 425 433 436

MEDICAL APPLICATION, 4 7 2122 23 24 25 26 28 29 30 31 3940 54 57 60 61 64 66 68 69 7179 91 100 106 115 128 131 133142 146 147 152 156 163 168170 172 174 176 178 180 183

Subject Index


185 186 188 197 203 205 206208 210 215 217 225 228 229250 254 255 257 263 264 265266 271 280 283 293 296 302303 308 311 314 315 323 330337 340 341 343 345 353 357360 361 363 364 370 373 378384 387 389 397 407 411 416431 435 444 445

MEDICAL EQUIPMENT, 83 100158 176 262 353

MELT TEMPERATURE, 104 307309

MELT VISCOSITY, 292 307 316329

MEMBRANE, 11 15 71 118 159185 188 243 263 294 311 402418 419

METAL ADHESION, 60 65 77 338METAL COATING, 336METAL FILLER, 41 218 336METAL INSERT, 150 194 250 295

331METAL REPLACEMENT, 14 391METERING, 9 89 229 243 321MICROMOULDING, 9 164MICROWAVE HEATING, 254MIGRATION, 15 20 21 66 82 103

137 195 217 298 300 304 389407

MILITARY APPLICATION, 96295 319 430

MILLING, 65 163 255 357MINERAL FILLER, 26 55 185 202

238 329 363 391MIXER, 157 311MIXING, 1 14 26 46 89 171 181

185 194 200 202 227 229 235246 248 250 287 291 309 311392 393 413 414 441

MOBILE PHONE, 60MODULUS, 131 200 219 249 269

291 295 450MOISTURE CURING, 6 138 363

408MOISTURE RESISTANCE, 137

159 185 274 377MOLECULAR STRUCTURE, 5 8

21 26 36 65 72 91 112 131 135138 163 177 185 187 195 200212 219 239 245 249 250 255267 292 312 316 328 346 363394 395 406 426 434 436 437446 447 448 450

MOLECULAR WEIGHT, 21 26 6568 69 138 152 185 195 200 213280 289 293 356

MOONEY VISCOSITY, 292MORPHOLOGY, 20 133 186 208

231 239 245 406MOTOR CYCLE, 19MOULD, 2 104 105 107 150 185

193 194 204 234 235 237 248250 257 272 288 307 311 320325 326 331 342 344 359 385393 398 405 423 431

MOULD CAVITY, 117 190 331MOULD CLOSING, 150 248MOULD COOLING, 193MOULD CYCLE, 150 185 193

248 250 331MOULD DESIGN, 9 18 49 67 105

204 243 331 344 405MOULD FILLING, 47 64 104 105

119 190 193 227 229 307 331MOULD FLOW, 257 307 331 342MOULD HEATING, 49 193 260

263 303 311 331MOULD INSERT, 83 331MOULD MAKING, 57 102 317MOULD RELEASE, 58 60 89MOULD RELEASE AGENT, 40

58 113 331 363 423MOULD SLIDE CORE, 65MOULD TEMPERATURE, 64 65

89 104 105 118 119 150 193202 207 211 227 229 248 250304 307 342 344 353

MOULDING, 9 10 14 16 18 19 2134 40 54 56 57 58 60 62 77 8291 107 154 162 163 164 179185 190 192 200 202 211 214231 234 270 288 290 304 311331 337 342 363 369 398 431

MOULDING COMPOUND, 58170 288 342 380 391 400 453

MOULDING FAULT, 248MOULDING PRESSURE, 47 190

248 250 307 326 414MOULDMAKING, 57 102 288

317 331 348MOULDS OF POLYMERS, 12 26

45 62 138 153 164 175 182 190194 237 272 288 305 320 331344 393 410

MULTI-CAVITY MOULD, 204248 250 311 342 385

MULTI-COMPONENT, 2 9 26 6479 105 132

MULTI-MATERIAL MOULDING,2 102 105

MUTAGEN, 389 399MYOSITIS, 297NANOSTRUCTURE, 231

NNATURAL RUBBER, 35 64 146

149 234 243 304NEOPRENE, 42 149 161NERVE REGENERATION, 283NIP GAP, 34NIPPLE, 37 163 224 227NITRILE RUBBER, 102 105 149

219NITROSAMINE, 304 407NITROSAMINE-FREE, 37NOISE REDUCTION, 319 367NON-ALLERGENIC, 173NON-RETURN VALVE, 273NON-STICK, 7NON-TOXIC, 25 173 229 303 311NOZZLE, 193 234 235 243 260NUCLEAR MAGNETIC

RESONANCE, 174 216 217245 253 267 280 420

NYLON, 14 25 60 64 89 105 125132 150 161 211 238 255 410

OO-RING, 77 95 269 303 327 368

386ODOUR-FREE, 303OFF-THE-ROAD VEHICLE, 124OFFICE EQUIPMENT, 89 219 306OFFSHORE APPLICATION, 185

352OIL PAN GASKET, 219 269 383

392 412OIL RESISTANCE, 11 60 77 148

159 191 202 219 249 269 287291 380 383 385 445

OIL SEAL, 202 347OLIGOMER, 304 309 328 329 346

363 423 447ONE-COMPONENT, 14 26 138

157 159 250 311 313 342 394400 408 409 422 439 446 449450 453

OPTIC FIBRE, 379OPTICAL APPLICATION, 12 16

21 36 57 264 277OPTICAL PROPERTIES, 14 21 22

25 56 131 141 185 194 202 212218 229 237 248 263 292 293295 303 312 331 353 379

OPTOELECTRONICAPPLICATION, 36 386

ORGANOLEPTIC PROPERTIES,213

ORGANOSILICONE POLYMER,9 16 21 27 37 38 40 43 55 59

Subject Index


66 70 75 78 84 85 86 87 88 9093 94 97 103 110 113 114 121122 123 124 126 134 135 140142 143 151 154 156 166 168179 195 197 199 203 205 206207 208 209 210 220 226 230232 233 238

OUTGASSING, 77 121 126 331437

OVEN CURING, 25 26 185 200202

OVERMOULDING, 11 60 64 6589 105 150 238

OXIDATION, 141 217 278 314437

OXIDATION RESISTANCE, 26185 293

OXIDATIVE DEGRADATION,141 217 278 314 437

OXIME, 450OXYGEN INDEX, 249OZONE RESISTANCE, 26 35 65

248 250 293 311 343 363 380437

PPACKAGING, 86 270 400 408PAD, 228 345PAINT, 237 390 408 448PAINTABILITY, 90PAPER COATING, 25PARTING LINE, 45 194 331PASTE, 248 250 295 422PATENT, 176 179 192 376 382PEEL STRENGTH, 64 90 105 261

440PELLET, 54 211PENTASILICIC ACID, 216PERFLUOROELASTOMER, 77PERMEABILITY, 21 138 177 264

267 418 419PERMITTIVITY, 371PEROXIDE, 1 26 101 138 157 159

185 200 218 222 241 250 292295 342 363 377 392 446 449

PEROXIDE VULCANISATION,46 67 138 159 163 185 200 218250 271 291 292 295 396

PHARMACEUTICALAPPLICATION, 25 98 131 184188 221 267 293 301 340 402416

PHENYLSILICONE RESIN, 381PHOTOCONDUCTIVITY, 312PHOTOCROSSLINK, 14 107 182

346 442PHOTODEGRADATION, 312 437

PHOTOINITIATOR, 312 346 442PHOTOLITHOGRAPHY, 71 141PHOTORESIST, 12 141 277 312

442PHOTOSENSITISER, 59 346PHYSICAL PROPERTIES, 45 58

69 112 177 222 239 241 244364 384 394 417 426 434 439445 453

PHYSICOCHEMICALPROPERTIES, 183 221 300

PHYSICOMECHANICALPROPERTIES, 68 152

PIGMENT, 14 194 248 249 250255 295 311

PIPE, 352PIPE LINING, 149PISTON, 2 150PLASMA TREATMENT, 21 141

419PLASTICISATION, 104 385PLASTICISER, 127 131 185 255

304 408PLATELET ADHESION, 39PLATINUM, 1 3 10 26 33 51 88 94

95 97 138 157 185 195 202 232241 250 304 331 342 346 377434

PLATINUM CURING, 46 241 271PLUG, 27 67PLUNGER, 385 401POLYADDITION, 64 129 143 213

423POLYAMIDE, 14 25 60 64 89 105

125 132 150 161 211 238 295314 410 448

POLYBUTYLENETEREPHTHALATE, 60 64 105229 238 261

POLYCARBONATE, 14 237 238261

POLYCARBORANE SILOXANE,371

POLYCARBOSILANE, 56 155312

POLYCARBOSILOXANE, 72POLYCHLOROPRENE, 42 149

161 249 394POLYCONDENSATION, 85 143

191 423 435 446POLYCYCLOSILOXANE, 85POLYDIBUTYLPHENYLSILANE,

36POLYDIETHYLSILOXANE, 420POLYDIHEXYLSILANE, 312POLYDIMETHYL SILOXANE, 4

21 22 31 32 92 98 101 103 115131 137 141 178 183 186 197

200 202 203 213 214 216 217221 225 231 245 246 256 267280 283 292 293 299 300 309316 397 428

POLYDIMETHYLPHENYLSILOXANE,371 435

POLYEPOXIDE, 12 19 138POLYETHYLENE, 14 128 237

249 287 314 344 377 394POLYETHYLMETHYLSILOXANE,

418POLYFLUOROSILOXANE, 21POLYIMIDE, 177 265 417 448POLYMERISATION, 4 56 78 85

90 129 155 184 272 293 312363 390 425

POLYMETHYLMETHACRYLATE, 14 231 278305 344

POLYMETHYLOCTYLSILOXANE,418

POLYMETHYLPHENYLSILOXANE, 293

POLYMETHYLPHENYLSILANE,36 212 354

POLYMETHYLPHENYLSILOXANE,418

POLYMETHYLPHENYLSILYLENE,406

POLYMETHYLPROPYLSILOXANE,418

POLYMETHYLSILOXANE, 152380 433

POLYMETHYLTRIFLUORO-PROPYLSILOXANE, 418

POLYMETHYLVINYLSILOXANE, 396

POLYORGANOSILOXANE, 4 916 21 22 27 31 32 37 38 40 4355 59 66 75 78 84 85 86 87 9092 93 94 97 98 101 103 110 113114 115 121 122 123 124 126134 135 140 142 143 151 154156 165 166 168 179 195 197199 203 205 206 207 208 209210 220 226 230 232 233 238285

POLYPHENYL SILOXANE, 380POLYPHENYLENE ETHER, 64

238POLYPHENYLENE OXIDE, 238POLYPHENYLENE SULFIDE,

400POLYPHENYLENE VINYLENE,

354POLYPHENYLMETHYL

SILOXANE, 437 447POLYPROPYLENE, 237 265 349

Subject Index


377POLYSILETHYLENESILOXANE,

418POLYSILHEXYLENE

SILOXANE, 418POLYSILOXANE ACRYLATE, 21POLYSILOXANE-URETHANE,

21POLYSTYRENE, 87 133 237 238

245 293POLYSULFIDE, 14 408 422POLYTETRAFLUOROETHYLENE,

35 82POLYTRIFLUOROPROPYL-

METHYLSILOXANE, 437POLYURETHANE, 14 21 30 52 99

100 133 134 136 138 146 152192 206 226 231 268 305 306314 318 319 325 328 331 341350 351 352 358 381 389 390394 408 421 422

POLYURETHANE ELASTOMER,138 139 239 389

POLYVINYL CHLORIDE, 6 14100 146 249 268 314

POLYVINYL SILOXANE, 14 53POLYVINYLPYRROLIDONE,

370POROSITY, 3 168 172 218 283

331 361POST CURING, 26 64 105 185

200 202 218 248 304 331 342363

POST FORMING, 319POT LIFE, 89POTTING, 59POTTING COMPOUND, 293 380

400 417 453POWER TRANSMISSION, 137PRECIPITATED SILICA, 292PRECISION MOULD, 190 202

326 405PRECURING, 200PRECURSOR, 13 16 312 426PREFORM, 117PREHEATING, 2 331PREPREG, 400PRESSURE, 34 104 157 190 193

200 202 227 246 269 292 294307 309 310 344 428

PRESSURE CONTROL, 229PRESSURE RESISTANCE, 218

269PRESSURE SENSITIVE, 121 126

275 372 377 380 423 429 434435

PRICE, 7 11 77 102 179 341 400445

PRIMER, 421 422 435PRIMERLESS, 65PRINTED CIRCUIT, 380 390 400PRINTING, 116 238 442PROCESSABILITY, 18 48 65 77

100 118 246 381PROCESSING, 12 18 25 26 46 67

79 91 99 120 131 148 163 169181 185 192 207 237 241 244250 251 255 257 263 295 303311 348 353 364 376 379 382401 416 446

PROCESSING AID, 304PRODUCT ANNOUNCEMENT, 9

13 27 102 156 176 180 192 196243 257 284 306 330 337 339349 355 362 369 373 378 382386 387 390 400 404 408 409411 421 436

PRODUCT DESIGN, 28 119 189234 237 257 294 331

PRODUCT DEVELOPMENT, 1118 60 126 237

PRODUCTION, 148 180 255 453PRODUCTION COST, 18 150 224

235 237 243 248 342PRODUCTION RATE, 60 263 305

310PRODUCTIVITY, 54 150 175 179

220 243 248 257 342 445PROFILE, 151 185 292 359 363PROSTHESIS, 14 26 57 61 122

142 152 167 217 236 250 286296 344 356 361 366 389

PROTECTIVE CLOTHING, 25263 303 311 313 353 364 378

PROTECTIVE COATING, 43 187390 426 453

PROTEIN, 86 217 283 293 389PROTOTYPE, 26 83 141 175 180

193 194 237 320 325 331 341344 393

PSEUDO GEL, 142PULL STRENGTH, 16PUMP, 229 235 271PURITY, 77 271 329 453PUTTY, 170 254 302 337 398PYROGENIC, 157PYROLYSIS, 177 312 407 426

QQUALITY, 54 126 132 150 168

234 241 262 263 273 310 353364 378 386 413 445

QUARTZ, 14 162 441QUICK COLOUR CHANGING, 2QUICK MOULD CHANGING, 326

RRACING CAR, 412RADIATION CROSSLINKING,

59 68 103 250 396 434 449RADIATION DEGRADATION,

131RADIATION RESISTANCE, 313

343 352RADIATION STERILISATION, 7

131RADIATOR, 159RADIOIMMUNOASSAY, 268RAILWAY, 72 375 408RAPID PROTOTYPING, 26 83

305RAPID TOOLING, 83 237REACTION INJECTION

MOULDING, 251 341RECYCLING, 161 200 255 263

282 303 311 349 353 364 377385

RED IRON OXIDE, 157REFRACTIVE INDEX, 45 312REFRIGERATOR, 238REGULATION, 77 242 304 322

390 416REINFORCED PLASTIC, 14 19

142 150 153 183 196 210 238240 245 317 319 323 335 336337 360 374 382 385 391 400410 417

REINFORCED RUBBER, 13 50106 158 295 357

REINFORCEMENT, 58 150 256425 444 446

REJECT RATE, 126RELEASE AGENT, 40 58 82 113

140 372RELEASE COATING, 372 377

428 429 434RELEASE PROPERTIES, 168 218

377 423REPLICATION, 12 164 231REPRODUCIBILITY, 98 104 193RESIDENCE TIME, 200 309RESILIENCE, 108 131 218 243

342RESISTIVITY, 65 127RESTORATION, 138 443RETARDER, 53REVIEW, 9 43 46 50 70 78 80 90

91 94 102 120 122 127 129 139140 144 145 146 148 149 155177 187 241 245 253 258 264277 293 297 298 299 316 328346 351 352 365 369 372 376377 381 388 389 394 395 396

Subject Index


406 407 414 415 417 418 419420 421 422 423 425 426 427428 429 430 431 432 433 434435 436 437 439 440 441 442443 444 445 446 447 448 449450 451 452 453

RHEOLOGICAL PROPERTIES,10 14 18 25 26 49 51 53 65 7782 104 105 115 119 138 142157 160 161 173 184 191 200213 220 246 248 250 292 293307 309 310 316 331 342 363380 417 420 425

RHEOMETRY, 94 157 241 246292 310 342 401

RHEUMATISM, 297RIFAMPICIN, 221RIGID, 52 64 105 190 394RING-OPENING

POLYMERISATION, 85 328406 446 451

ROBOT, 2 102 150 193 229 234325 327

ROCKER COVER, 269 321ROLLER, 34 139 160 218 219 227

306 343ROOFING, 394ROOM TEMPERATURE

VULCANISATION (RTV), 2526 38 48 81 94 138 159 164191 201 238 250 255 256 313368 380 381 392 423 439 443444 446 449

ROTATING TABLE, 150 385ROTATIONAL MOULDING, 64

105 360RUBBERISED FABRIC, 313RUNNER, 193 307 331RUPTURE, 122 142 428

SSAFETY, 271 322 331 352 362 364

407SAG FACTOR, 201SALES, 11 102 156 179 223 226

368 445SALICYLIC ACID, 188SALIVA, 14 236SALT FOG RESISTANCE, 189

295SANITARYWARE, 422SCANNING ELECTRON

MICROSCOPY, 4 61 133 172177 186 198 221 245 308 315366

SCORCH, 64 105 200 342SCRAP, 150 200 263 269 303 311

342SCRAP REDUCTION, 150 248

250 329 342SCRATCH RESISTANCE, 331SCREW, 160 193 235 246 273 309SCREW SPEED, 200 246 309SEAL, 9 15 18 27 35 38 60 76 77

81 84 95 99 119 121 123 126130 150 159 179 181 185 202211 219 223 227 235 250 269273 291 293 294 295 303 306311 321 327 336 347 352 353362 363 367 374 383 385 386392

SEALANT, 6 7 38 40 48 65 81 90114 124 127 226 255 327 339352 365 368 394 395 404 408422 430 437 438 439 450 453

SEALING, 9 84 324 343 352 383SEALING STRIP, 108SEAT, 14SELF-ADHESIVE, 11 25 26 65 89SELF-EXTINGUISHING, 238 248SELF-LUBRICATING, 15 60 159

185 248 250 263 303 311SEMI-FLEXIBLE, 62SEMICONDUCTOR, 5 75 77 312

329 380SENSITISATION, 131SENSOR, 32 159 275SERVICE LIFE, 6 28 35 166 173

175 189 218 219 269 272 291331 338 347

SERVICE TEMPERATURE, 77SHEAR, 84 89 124 157 200 246

292 294 310 420SHEAR RATE, 184 200 246 292

307 310SHEATH, 62 147SHEET, 55 200SHEET MOULDING

COMPOUND, 14SHELF LIFE, 89 218 342SHELL, 152 195SHIELDING, 337SHIP, 72SHOCK ABSORBER, 159 284 375

392SHORE HARDNESS, 107 129 182SHORT PRODUCTION RUN, 320

341SHOT CAPACITY, 150 374SHOT WEIGHT, 193 273SHOWER, 60 422SHRINKAGE, 12 14 90 157 162

272 305 329 331 348 398SILANOL GROUP, 85 138 211SILICA, 14 33 58 92 95 106 112

131 138 157 162 167 185 202217 218 219 222 245 251 256276 292 363 391 392 395 408423 441 444 446

SILICON CARBIDE, 312 426SILICON-29, 217SILICONE COPOLYMER, 21 88

115 264 351 387 444 452SILICONE OIL, 15 25 26 80 213

363 392 395SIMULATION, 105 132 178 246

292 304 310 325SINGLE-COMPONENT, 14 26

138 157 159SLIP, 246SMALL-COMPONENT, 159 193

248 263 303 311 353 364SMOKE, 26 185 249 352 381SNAP-FIT, 77SOCKET, 344SOFT CONTACT LENSES, 21SOFT-TOUCH, 103SOFTWARE, 83 180 220 294 307

325SOLAR CELL, 417SOLUBILITY, 21 177 217 293 309

363 425SOLUTION CASTING, 360SOLVENT, 21 69 155 356 443SOLVENT EXTRACTION, 69 200

304SOLVENT RESISTANCE, 148 356SOLVENTLESS, 25 161 377 390

408 434SOUND ATTENUATION, 196SOXHLET EXTRACTION, 101

200SOYABEAN OIL, 195SPACE APPLICATION, 417SPARK PLUG, 219 235 250 392SPIN CASTING, 175SPORTS EQUIPMENT, 194 311SPRAYING, 62 288 295 357 408SPREADING, 352SPRUE, 331SPRUELESS, 9STABILISER, 157 250 293 304STABILITY, 21 46 90 121 126 129

148 159 185 202 205 352 357381 395

STANDARD, 34 93 96 157 161262 304 319 324 332 333 334335 353 362 365 377 383

STAPHYLOCOCCUS, 236 278STATIC, 218 375STATIC MIXER, 305 311STATISTICS, 7 35 40 50 77 90 102

118 148 161 179 181 185 226

Subject Index


255 257 368 413 445STEAM CURING, 26STEEL, 295 422STEERING WHEEL, 11STERILISATION, 7 131 239 311

389STICK-SLIP PROPERTIES, 440STRAIN, 200 236 294 295STRENGTH, 17 50 53 65 94 129STRESS, 28 50 92 189 246 283

294 310 329 379 437STRESS RELAXATION, 114 219

269 310 383STRESS-STRAIN PROPERTIES,

174 200 294SUBCUTANEOUS, 399SULPHUR VULCANISATION,

304SURFACE CRACKING, 292SURFACE DEGRADATION, 137SURFACE ENERGY, 65 103 137

189SURFACE FINISH, 87 103 218

237 248 273SURFACE PROPERTIES, 20 61

64 68 71 105 128 172 186 206214 218 239 292 300 425 437453

SURFACE TREATMENT, 21 4189 135 211 237 238 295 331363 370

SURFACTANT, 53 90 103 293SURGICAL APPLICATION, 4 14

31 100 111 122 131 134 135146 152 167 195 198 199 216236 239 242 253 259 266 279296 300 318 338 344 350 358366 387 389 397 407 409 411416 425 431 435 444 445

SURGICAL TUBING, 100 131250 384

SWELLING, 21 69 90 101 157 188200 202 213 256 287 291 295310 356 380 383

SWITCH, 11SYNTHESIS, 85 155 184 197 258

264 316 328 346 351 357 376406 424 426 439 444 446 447

SYNTHETIC LEATHER, 325SYNTHETIC RUBBER, 90 96 101

120 165SYRINGE, 115 263 303 311 353

TTACK, 17 114 228 342 345TAKE-OFF SYSTEM, 273TAKEOVER, 40 223 368

TALC, 162TAPE, 96 377TEAR STRENGTH, 25 53 63 65

77 93 131 138 161 162 167 185202 218 228 248 249 250 269291 295 331 342 345 433 444

TEAT, 37 163 224 227 304 311 353TELECOMMUNICATIONS

APPLICATION, 194 238 336TELESCOPE, 417TELEVISION, 194 222 238TEMPERATURE CONTROL, 2

104 158 193 273 303 342TEMPERATURE DEPENDENCE,

47 50 130 212 246TEMPERATURE RANGE, 35 65

173 229 255 258 319 336TEMPERATURE RESISTANCE,

67 91 189 364 377 381 394TEMPLATE, 107 182 283TENSILE PROPERTIES, 4 21 24

65 69 95 101 124 125 129 157167 174 200 202 205 218 219228 235 250 291 312 342 345363 392 394 408 422 433 441444 445

TEST EQUIPMENT, 93 94 178325 386

TEST METHOD, 65 68 93 103 137180 189 304 325

TESTING, 65 68 93 94 103 137178 180 189 217 243 244 262271 304 325 333 362 365 367386 389 390 394 395 398 399407 413 416 432 434 440

TETRAMETHYLDISILOXANEDIOL, 216

TEXTILE, 25 140 257 378 364THERMAL CONDUCTIVITY, 10

25 218 246THERMAL DEGRADATION, 65

177 202 219 389 392 394 400413 453

THERMAL EXPANSION, 248 317329 331 380

THERMAL INSULATION, 55 118319 381 394

THERMAL PROPERTIES, 25 2650 56 98 104 131 161 218 245246 247 248 258 293 295 307309 317 331 363 379 380 402425 453

THERMAL STABILITY, 7 11 1425 26 46 48 50 60 64 77 90 105121 126 129 131 138 148 159169 179 185 194 202 218 219227 229 235 248 250 258 263269 290 291 293 295 303 311

313 329 343 353 363 380 385391 392 412 422 437 445 448453

THERMOFORMING, 14THERMOLYSIS, 3 312 407THERMOPLASTIC

ELASTOMER, 62 64 102 127223 235 304

THICK-WALL, 104THICKNESS, 21 25 105 188 237

239 326 331 383THICKNESS CONTROL, 237THIN FILM, 42 44 168THIN-WALL, 104 105 238 331

357THROMBECTOMY, 176THROMBORESISTANCE, 183TIEBARLESS, 234 243 326TIN COMPOUND, 61 129 201 250

302 331 337 434TISSUE EXPANDER, 308TISSUE RESPONSE, 217 239 283

384TITANIUM COMPOUND, 59 162

278 295 415 426TOGGLE, 102 248 326TOLERANCE, 83 104 235 237

294TOOLING, 19 60 153 227 237 317TOOTH RESTORATION, 14TOXICITY, 14 25 131 143 185 192

249 263 271 303 304 352 358362 381 389 390 396 407 438

TOYS, 194 237TRACKING RESISTANCE, 219TRADE NAME, 2 14 25 26 131

159 193 202 219 238 249 250263 313 353 389 392 405

TRAFFIC CONTROL, 275TRANSDERMAL, 98TRANSFER MOULDING, 91 163

185 329 342 380 400 453TRANSLUCENT, 25 272TRANSMISSION FLUID, 202 291TRANSPARENCY, 21 103 107

131 141 185 194 202 229 232237 248 257 263 264 289 292303 305 353 364

TRANSPORT APPLICATION, 362381

TRANSPORT PROPERTIES, 298354

TREND, 100 103 339TRIMETHOXYVINYLSILANE,

408TROUBLESHOOTING, 160TRUCK, 124 413TUBING, 7 100 131 162 185 250

Subject Index


252 262 271 310 343 352 363387

TUMOUR, 337 399TURBOCHARGER HOSE, 413TWIN-SCREW EXTRUDER, 230

246 309TWO-COMPONENT, 9 11 15 26

42 47 53 65 89 105 125 138150 157 159 161 179 202 224227 229 238 248 250 263 303305 310 311 313 321 325 364374 378 385 393 394 422 439446 449 453

UUNDER-THE-BONNET

APPLICATION, 35 77 89 159166 185 202 219 269 291 294321 327 367 380 385 392 400427

UNDERWATER APPLICATION,158

UNSATURATED POLYESTER,138 335 374 385

UV CURING, 14 25 238 372 377379

UV RADIATION, 137 346UV RESISTANCE, 35 185 189 226

250 311 377 381 394 408

VVACUUM, 190 229 309VACUUM BAG MOULDING, 410VACUUM CASTING, 26 194 237

320 331 341 393VACUUM FORMING, 14 190VACUUM MOULD, 248VALVE, 185 385VALVE COVER, 219 269 374 385

412VANDAL PROOF, 219VARNISH, 103 140VASCULAR PROSTHESIS, 268VEHICLE DOOR, 238VEHICLE ENGINE, 159 219 269

385VEHICLE IGNITION, 219VEHICLE LIGHT, 238VEHICLE RADIATOR, 159VEHICLE SPOILER, 408VEHICLE SUSPENSION, 375VENTING, 49 190 309 331VERTICAL MACHINE, 2 102 349VIBRATION DAMPER, 159 293

367 392

VINYL GROUP, 110 200 202 211VISCOELASTIC PROPERTIES,

213 286 292 310VISCOSITY, 10 14 18 25 26 49 51

53 65 77 82 101 104 115 119138 157 160 173 184 191 200213 246 248 250 255 292 293307 310 331 363 380

VOICE PROSTHESIS, 61 236 366VOID, 112 331VOID-FREE, 341VOLATILE, 85 110 309 438VOLATILITY, 269 293 304 438VOLUME RESISTIVITY, 249 336

371VULCANISATION, 2 25 26 46 67

78 79 101 105 106 131 138 150159 162 163 171 181 185 193194 200 202 218 219 248 249250 260 263 292 295 301 303304 307 310 311 313 331 342348 353 359 363 380 383 392396 424 425 444 449

VULCANISATION TIME, 2 6 2660 129 131 138 150 185 200202 229

WWALL SLIP, 246 292WALL THICKNESS, 18 64 105

310 331 341WASHER, 150 383WASHING, 137 304WASTE, 173 200 263 271 303 311

353WATER, 20 85 188 217 236 263

303 443WATER ABSORPTION, 65 379

421 422 437 443 448 453WATER EXTRACTION, 304WATER PERMEABILITY, 138

423 443WATER REPELLENT, 72 159 187

448WATER RESISTANCE, 20 21 60

72 293 338 421 422 437 443448

WATERPROOFING, 27 138 187423

WAX, 58 110 138WEAR RESISTANCE, 14 34 42

119 145 161 218 306WEATHER RESISTANCE, 6 7 72

77 226 255 290 348 352 381394 395 422

WEATHER STRIPPING, 88 219233 367

WEATHERING, 6 72 77 249 255290 343 380 394 395 422 437443

WEIGHT LOSS, 157 293 309 398WEIGHT REDUCTION, 161 234

243 336WETTABILITY, 20 21 53 65 109WETTING, 92 103 167 264WINDOW, 88 138 238 362 422WINDSCREEN WIPER BLADE,

35 82 159WIRE, 73 112 249 332 334 368

445 453WIRING HARNESS, 319WOOD FINISH, 103WORK SURFACE, 408

XX-RAY CONTRAST MATERIAL,

119

YYIELD, 155 246 426YOUNG’S MODULUS, 4 5 21 84

167 271 292 294 379

Silicone Elastomers

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