Unsaturated Polyester Resins and the EU ... - Composites UK
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Unsaturated polyester resins & the EU VOC Directive* *(Council Directive 1999/13/EC of 11 March 1999 on the limitation of emissions of volatile organic compounds due to the use of organic solvents in certain activities and installations). Background Since the introduction of the European VOC Directive there has been uncertainty about its applicability to the Fibre Reinforced Plastics (FRP) industry, both from legislative authorities in various countries as well as in the FRP industry within the EU. In some EU member States, the FRP industry has been penalised by legislators attempting to enforce legislation that does not apply to the activity in question. Therefore Plastics Europe Unsaturated Polyester (UP) technical group has assessed the position of the FRP industry with reference to the Directive. This position paper provides guidance with respect to the applicability of the Directive to the FRP industry. The Fibre Reinforced Plastics (FRP) moulding process. The FRP moulding process is a versatile means of converting an unsaturated polyester resin (a solid polymer at room temperature), dissolved in a volatile, reactive, unsaturated monomer, (usually styrene), in combination with reinforcing fibres (usually glass fibre) into structural materials, generally referred to as fibre reinforced laminates or fibre reinforced composites. In most processes where solvents are used, all of the solvent is released during the process: and unless emission restriction controls are in place, all of the solvent is released into the atmosphere. However, during the cure of unsaturated polyester resins, styrene - the reactive monomer in which the unsaturated polyester is dissolved - co-polymerises with the reactive sites in the unsaturated polyester chains to form a three dimensional solid: in other words a thermosetting plastic. The diagram below (courtesy SpecialChem), shows the cross-linking mechanism of UP resins. In some FRP processing techniques, a very small proportion of the reactive monomer may escape into the atmosphere before copolymerisation. Strategies for dealing with styrene emissions are the subject of other Technical Bulletins within this series. Definitions The VOC Directive contains terminology that may differ in meaning to what is commonly accepted within the FRP industry. An understanding of the difference in the interpretation of the vocabulary used within the VOC Directive and that used within the FRP industry is essential for a qualified decision to be made on the relevance of the VOC Directive to the FRP industry. Organic solvents In the FRP industry, the styrene in the resins is cross- linked with the unsaturated polyester. This means that very little of the volatile monomer is released into the atmosphere during processing. The VOC Directive defines an organic solvent as follows: ‘A VOC used alone or in combination to dissolve raw materials without undergoing a chemical change or as a cleaning agent, dispersion medium, a viscosity adjuster, a surface tension adjuster, a plasticiser, a preservative.’ Applicability to the FRP industry: As styrene undergoes a chemical change during processing of the unsaturated polyester resin, it cannot be defined as an organic solvent within the terms of the VOC Directive. Only if styrene were to be used for cleaning purposes (which is rarely the case), would it possibly fall within the VOC directive. Industrial activities In Annexe 1 of the Directive, twenty activities are cited for which the Directive is valid. These activities include ‘wood and plastics lamination’ which is defined as: ‘Any activity to adhere together wood and/or plastic to produce laminated products.’ Applicability to the FRP industry: Only this ‘wood and plastics lamination’ category activity appears to have anything remotely relevant to FRP fabrication. But in the product resulting from the ‘wood and plastics lamination’ process, the individual layers of which the product is built up, can still be distinguished and recognised. This is not the case in the FRP process since the resulting laminate is homogenous. During FRP fabrication, glass fibres are impregnated with unsaturated polyester resin. After the curing or cross-linking of the UP resin with the styrene monomer, the glass fibres cannot be distinguished as separate layers in the product. Although this process is called ‘lamination’, it has nothing in common with the ‘wood and plastics lamination’ as described under Annexe 1 of the Directive. TECHNICAL BULLETIN UP RESIN GROUP 1 13 Version: 2/05/06. To check if this is the current version visit www.plasticseurope.org Continued
Transcript of Unsaturated Polyester Resins and the EU ... - Composites UK
Unsaturated polyester resins & the EU *(Council Directive 1999/13/EC of 11 March 1999 on the limitation of emissions the use of organic solvents in certain activities and installations). Background Since the introduction of the European VOC Directivethere has been uncertainty about its applicability to theFibre Reinforced Plastics (FRP) industry, both fromlegislative authorities in various countries as well as inthe FRP industry within the EU. In some EU memberStates, the FRP industry has been penalised bylegislators attempting to enforce legislation that doesnot apply to the activity in question. Therefore PlasticsEurope Unsaturated Polyester (UP) technical grouphas assessed the position of the FRP industry withreference to the Directive. This position paper providesguidance with respect to the applicability of theDirective to the FRP industry. The Fibre Reinforced Plastics (FRP) mouldingprocess. The FRP moulding process is a versatile means ofconverting an unsaturated polyester resin (a solidpolymer at room temperature), dissolved in a volatile,reactive, unsaturated monomer, (usually styrene), incombination with reinforcing fibres (usually glass fibre)into structural materials, generally referred to as fibrereinforced laminates or fibre reinforced composites. In most processes where solvents are used, all of thesolvent is released during the process: and unlessemission restriction controls are in place, all of thesolvent is released into the atmosphere. However,during the cure of unsaturated polyester resins,styrene - the reactive monomer in which theunsaturated polyester is dissolved - co-polymeriseswith the reactive sites in the unsaturated polyesterchains to form a three dimensional solid: in otherwords a thermosetting plastic. The diagram below(courtesy SpecialChem), shows the cross-linkingmechanism of UP resins. In some FRP processing techniques, a very smallproportion of the reactive monomer may escape intothe atmosphere before copolymerisation. Strategies fordealing with styrene emissions are the subject of otherTechnical Bulletins within this series.
Definitions The VOC Directivediffer in meaning tothe FRP industry. Athe interpretation oVOC Directive and tessential for a quarelevance of the VO Organic solvents In the FRP industrylinked with the unsavery little of the volatmosphere during The VOC Directivefollows: ‘A VOC used alonematerials without uas a cleaning agenadjuster, a surfacepreservative.’ Applicability to theAs styrene undergprocessing of the unbe defined as an othe VOC Directive. cleaning purposes possibly fall within t Industrial activitiesIn Annexe 1 of the for which the Direct‘wood and plastics l‘Any activity to adhproduce laminated p Applicability to theOnly this ‘wood aactivity appears to FRP fabrication. Bu‘wood and plastics layers of which thedistinguished and rthe FRP process homogenous. Durinimpregnated with uncuring or cross-linkimonomer, the glassseparate layers in thcalled ‘lamination’, ‘wood and plasticsAnnexe 1 of the Dire
TECHNICAL BULLETIN
UP RESIN GROUP
Version: 2/05/06. To check if this is the c
VOC Directive*of volatile organic compounds due to
contains terminology that may what is commonly accepted within n understanding of the difference in f the vocabulary used within the hat used within the FRP industry is lified decision to be made on the C Directive to the FRP industry.
, the styrene in the resins is cross-turated polyester. This means that atile monomer is released into the processing.
defines an organic solvent as
or in combination to dissolve rawndergoing a chemical change or t, dispersion medium, a viscosity
tension adjuster, a plasticiser, a
FRP industry: oes a chemical change during saturated polyester resin, it cannot rganic solvent within the terms of Only if styrene were to be used for (which is rarely the case), would it he VOC directive.
Directive, twenty activities are cited ive is valid. These activities include amination’ which is defined as: ere together wood and/or plastic to roducts.’
FRP industry: nd plastics lamination’ category
have anything remotely relevant to t in the product resulting from the lamination’ process, the individual product is built up, can still be
ecognised. This is not the case in since the resulting laminate is
g FRP fabrication, glass fibres are saturated polyester resin. After the ng of the UP resin with the styrene fibres cannot be distinguished as e product. Although this process is
it has nothing in common with the lamination’ as described under ctive.
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urrent version visit www.plasticseurope.org
Continued
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TECHNICAL BULLETIN (continued)
The term ‘laminate’ as used in the FRP industry is not defined in the Directive. It can therefore be concludedthat the lamination process, as commonly referred to inthe FRP fabrication / moulding industry, cannot beclassified under the Directive category ‘wood andplastics lamination’.
FRP position: Since styrene canwith respect to itresins under the lamination proceindustry has nocalled ‘wood aconclude that Anfor the applicatiomoulding industry
1. The VOCnot appmonome
2. The VOCto contrrespect material.
3. EU Memlocal auindustry Directive
Relation to DirecDirective 2004/4emissions of volathe use of orgavarnishes and vmore focused on referred to in activities. HowevDefinitions states‘The mass of voproduct which repart of the coatinVOC content’. FRP position: So once again than organic compconsidered to be
Water-based cleaning systems require no special storage precautions.
This publication is iinformation is providbest information cuuser’s own risk. Theprovided in good faauthors are aware, with regards to its cfor damages of anyor reliance on the in
The diagram above shows a cross section of laminate flooringand is a good example of ‘wood and plastic lamination’ asdefined in the Directive. Here a melamine resin is used toprovide a protective coating to the wood based core in adistinctive build-up of layers. By contrast, in the FRPlamination process (below), the resin completely ‘wets out’the glassfibre to form an integrated and homogenousstructure.
Annex II and annex III of the VOC Directive Annex II of the Directive specifically targets coatingactivities in the vehicle coating industry. Annex IIBconcerns the principles and practices for emissionreduction for the activities outlined in the Directive. Annex III provides details of a plan for guidance onsolvent management.
‘Lamination’ as it is understood in the FRP industry
not be defined as an organic solvents use as a reactive monomer for UPterms of the VOC Directive, and thess as used in the FRP fabricationthing in common with the processnd plastics lamination’, we mustnexes II, IIB and III are not relevantn of the VOC Directive to the FRP. Therefore:
Directive, as it stands today, doesly to processes where reactive,r type, solvents are used. Directive can therefore not be used
ol the FRP moulding industry withto emissions of volatile organic
ber State legislators should directthorities that the FRP mouldingdoes not have to comply with this, in its present form.
tive 2004/42/CE: 2/EC deals with the limitation oftile organic compounds arising fromnic solvents in certain paints andehicle refinishing. This Directive ispaints and varnishes but may also beconjunction with UP resin relateder, the Directive under Article 2 /: latile organic compounds in a givenact chemically during drying to formg, shall not be considered part of the
is directive follows the same pattern:ound which reacts chemically is nota VOC.
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ntended for guidance only and while the ed in good faith and has been based on the
rrently available, is to be relied upon at the information contained in this document is
ith and, while it is accurate as far as the no representations or warranties are made ompleteness and no liability will be accepted nature whatsoever resulting from the use of formation contained in the publication.
PlasticsEurope Avenue E. van Nieuwenhuyse 4 B-1160 Brussels, Belgium Telephone + 32 2 676 1732 Fax +32 2 675 3935 Email [email protected] www.plasticseurope.org
Typical ‘wood and plastic lamination’ as describedin the Directive
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