Report on PARC

[1]

IN-PLANT TRAININGREPORT

At

\

(1st July to 28thJuly)

Product Application and Research Centre,(P.A.R.C.)Chembur,Mumbai

Submitted by:

Suyash Trivedi

Central Institute of Plastics Engineering & Technology(C.I.P.E.T.)

Lucknow

[2]

Preface

The main purpose of this project was to provide us the opportunity to

expand our theoretical concepts and lessons to a practical level of

working, thereby helping us to understand the application of those

principles in real situations.

Therefore our college “Central Institute of Plastics Engineering &

Technology” gives due importance to this aspect of education by

providing us this internship in a reputed business house “Reliance

Industries Ltd – Product Application and Research Centre

(PARC)”, to enhance our practical experience.

Our area of work during the internship was to work in the lab and

perform various tests relating to plastics and in the processing area to

learn different processing techniques used for plastic.

This process has given us invaluable experience and enriched our skills

not only relating to polymer but also about raw materials, manufacturing

processes, testing etc.

We are thankful to PARC-RIL for providing us this good experience.

[3]

Acknowledgements

The training opportunity we had with Product Application and Research Center (PARC),

Reliance Industries Ltd (RIL) was a great chance for learning and professional

development. Therefore, we consider ourselvesas very lucky individuals as we were

provided with an opportunity to be a part of it. We are also grateful for having a chance

to meet so many wonderful people and professionals who led us though this internship

period.

We are deeply grateful to Mr. S.V.Raju, Head of the Department - Product Application

and Research Center (PARC), Reliance Industries Ltd (RIL) and Dr.Nitin V Joshi, Lab

in charge – PARC,RIL for extending its training facilities and giving us an opportunity

to gain an insight into the working of an industry.

We are using this opportunity to express our deepest gratitude and special thanks to

Mr.Nitin V. Joshi, our guide who in spite of being extraordinarily busy with his duties,

took time out to hear, guide and keep us on the correct path and allowing us to carry out

our training at their esteemed organization.

We would specially like to thank Mr. TusharDongre, Mr. Zubair Ahmed,Mr.Vinod

Kumar,Mr.Ajit Patel, Mr.Sundareshan,Mr.SunilMahajan,Mr. Surendra Gupta and

Mr. Kulkarni for their support and co-operation throughout the training period in spite of

their busy schedules.

Our sincere regards to Mr.Ravi Kumar, Mr. NileshBakare,Mr.RavindraKute,

Ms.RenukaSarode, Ms.SmithaKumbhare, Ms.NehaPawar, Ms.HimaPadhiar, Mr.

SoorajVadathala andMr.JigarPalecha for their continuous help during the training.

We are highly indebted to the executive & technical officers of PARC for their everyday

guidance and help and special thanks to Mr. AnantPawar, Mr.AjitGhate& Mr.

LalitPathaskar for their help in the processing centre.

Finally we would like to thank all the office and support staff for extending their

cooperation throughout the course of this training.

[4]

TABLE OF CONTENTS

Company Profile………………………………………………………..5

Manufacturing Facilities………………………………………………..7

Introduction to Polymers Testing at PARC………………………….…13

Introduction to PARC…………………………………………………24

Testing Division……………………………………………………….25

Processing Division……………………………………………………69

[5]

1. Company Profile

The Reliance Group , founded by Dhirubhai H. Ambani, is India's largest private sector enterprise,

with businesses in the energy and materials value chain. The flagship company, Reliance Industries

Limited, is a Fortune Global 500 company and is the largest private sector company in India.

Reliance Industries Limited (RIL) is an Indian conglomerate holding

companyheadquartered in Mumbai, Maharashtra, India. The company currently operates in

five major segments: exploration and production, refining and marketing,

petrochemicals,retail and telecommunications. The company is ranked114th on Fortune

Global 500 listof the world's biggest corporations for the year 2014. RIL is one of the

largest publiclytraded companies in India by market capitalization. It is the second

largest company inIndia by revenue after Indian Oil Corporation. RIL’s total turnover is

US$ 62.2 billionas of FY2014-15 making aa profit of US$ 3.8 billion. Reliance enjoys

global leadership in its businesses, being the largest polyesteryarn and fiber producer in the

world 2.5 million tons per annum and among the top five to ten producers in the world in

major petrochemical products.

RIL manufactures Polypropylene (PP), Polyethylene (PE) and Polyvinyl

Chloride(PVC) sold under the brand namesRepol, Relene&Reonrespectively.

Diverse applications across packaging, agriculture, automotive,

housing,healthcare, water and gas transportation and consumer durables.

Repol PP can turn any of your 'plastic' ideas into a reality.

Relene PE has completely transformed the concept of packaging.

Reon PVC is a versatile polymer with applications ranging from soft to rigid.

RIL has manufacturing sites atHazira, Nagothane, Jamnagar, Naroda and

Vadodara, Dahej, Allahabad, Dhenkanal, Barabanki, Kurkumbh, Nagpur,

Patalganga, Silvassa.

[6]

RIL is the largest producer of PE & PP in India.

Reliance's polymer business is integrated with its cracker facility at Hazira, as well as its

refinery at Jamnagar, ensuring feedstock availability at all times. The company operates

world-scale plants for Polyolefins and PVC with state-of-art technologies from global

licensors like Novacor, Geon and Union Carbide. Along with IPCL, Reliance is among the

world's top 10 plastic producers.

Reliance Industries Limited is Asia's largest manufacturer of Polypropylene (PP). Reliance

figures the fifth largest Polypropylene producers in the world. The four production sites

offer a wide range of Homopolymer, Random and Impact copolymer grades. These can

cater to the entire spectrum of Extrusion, Injection & Blow molding processes.

“Relene” HDPE is available in densities ranging from 0.941g/cc to 0.965g/cc & melt flow

index from as low as fractional to 20. Relene HDPE is widely used for numerous extrusion

& molding applications. Specially formulated HDPE Raffia grade has placed "Relene" way

above the competing materials for this application. The grade has excellent processability

on high output raffia lines & exhibits superior balance of tenacity / elongation.

Reliance LLDPE grades are marketed under trade name "Reclair" & is available in density

range of 0.916 to 0.935 g/cc & MFI range from fractional to as high as 50.

[7]

2. Manufacturing Facilities

1.Hazira

Hazira Manufacturing Division is located near Surat, Gujarat. It comprises of a Naptha

cracker feeding downstream fibre intermediates, plastics and polyester plants.

The first phase of the complex was commissioned in 1991-92 to generate power/utility and

to manufacture Ethylene Oxide (EO), Mono Ethylene Glycol (MEG), Vinyl Chloride

Monomer(VCM), Poly Vinyl Chloride (PVC) and High Density Polyethylene (HDPE). A

jetty was built for loading and unloading operation of raw material and final products.

The second phase of the project, started in 1995, involved commissioning of the Polyester

Complex (POY & PSF) and continued in full backward integration with commissioning of

the new Polypropylene (PP), Naphtha Cracker, Purified Terephthalic Acid (PTA) plants

and also involved expansion of existing phase 1 plants.

2.Jamnagar

Jamnagar Manufacturing Division is located near Jamnagar, Gujarat. It comprises of a

petroleum refinery and associated petrochemical plants. The refinery is equipped to refine

various types of crude oil (sour crude, sweet crude or a mixture of both) and manufactures

various grades of fuel from motor gasoline to Aviation Turbine Fuel (ATF). The

petrochemicals plants produces plastics and fibre intermediates.

The Polypropylene plant at Jamnagar has a huge capacity of 1030 KTA of Polypropylene

producing a wide range of grades that cater to an equally diverse range of sectors which

include Raffia, Films (BOPP/IPP), Injection Molding, Extrusion, Fibre etc.

The new PP line in the SEZ facility resulted in additional capacity of 900 KTA.

[8]

3.Allahabad

Allahabad Manufacturing Division located in Allahabad, Uttar Pradesh, is spread over 105

acres.It is equipped with batch polymerization and continuous polymerization facilities.

The batch plant produces wider range of specialty polymers and continuous plant produces

both commodity and differentiated products. Both the plants are equipped with pilot

positions to produce customer specific products and for development activities. The plant

also has integrated facilities of draw twisting, draw texturizing, Yarn Dyeing and Twisting.

The first phase of the plant was commissioned with a batch plant

in 1991 with technology from Toray Industries Inc. , Japan. In the second phase, the plant

was further expanded in 1997 with technology from Toray

Engineering Company, Japan. Since then, the plant has developed indigenous technologies

with its development activities to produce a large range of

Specialty polymers, for different downstream processes like draw twisting, draw warping,

draw texturizing, air texturizing etc.

4. Nagothane

Nagothane Manufacturing Divisionlocated in Raigad, Maharashtra, is spread over 1,860

acres.It comprises of an ethane and propane gas cracker and five downstream plants for the

manufacture of polymers, fibre intermediates and chemicals.

5.Patalganga

Patalganga Manufacturing Division located near Mumbai, Maharashtra, is spread over 200

acres. It comprises of polyester, fibre intermediates and linear alklyl benzene

manufacturing plants.

[9]

Products Manufactured:

Product Manufactured from

Para - Xylene (Px) Naphtha

Purified Terephthalic Acid (PTA) Para - Xylene

Polyester Filament Yarn (PFY) PTA & MEG

Polyester Staple Fibre (PSF) PTA & MEG

Linear Alkyl Benzene (LAB) Kerosene - n paraffin

6. Naroda

Naroda Manufacturing Division located near Ahmedabad, Gujarat, is RIL’s first

manufacturing facility. This synthetic textiles and fabrics manufacturing facility

manufactures and markets woven and knitted fabrics for home textiles, synthetic and

worsted suiting and shirting, ready to wear garments and automotive fabrics.

7.Dahej

Dahej Manufacturing Division is located near Bharuch, Gujarat. It comprises of an

ethane/propane recovery unit, a gas cracker, a caustic chlorine plant and 4 downstream

plants, which manufacture polymers and fibre intermediates.

The plant has its own facility for separating ethane/propane. The ethane / propane mixture

is used as a feedstock for the gas cracker plant.

The division was commissioned in two phases. The Caustic Chlorine, VCM and PVC

pants in phase one was commissioned in 1997. After this, in phase two, HDPE plant, MEG

plant, ethane / propane recovery plant and gas cracker unit were commissioned in 2000.

[10]

8. Hoshiarpur

RIL- Hoshiarpur Division is located in Hoshiarpur, Punjab. It manufactures a wide range

of PSF, PFF, POY and polyester chips.

The Plants at Hoshiarpur Manufacturing Divisional

The plants of PSF-I, PSF-II, POY, PFF are commissioned in 1989, 1995, 1995, 2004.

In addition to the regular products, Hoshiarpur Manufacturing Division has added the

following differentiated value added products:

1. Dope Dyed Olive Green & Khaki Fibre

2. Recron 3s for Construction & Paper Industry

3. Polyester Fibre Fill

4. Cluster Fibre

5. Conjugate Fibre

9. Nagpur

Nagpur Manufacturing Division is located in Nagpur, Maharashtra. It manufactures

polyester filament yarn, dope-dyed specialty products of different ranges, fully drawn yarn

and polyester chips.

The plant has facilities like housing for its employees, school, guest house and a Ganesha

temple.

RIL - Nagpur Manufacturing Division is an ISO: 9001:2000 certified unit accredited by

BVQI, along with certification for ISO14001: 2004 and OHSAS 18001:1999 as well.

Products Manufactured:

1. Polyester Filament Yarn (PFY) from PTA & MEG

2. DD Specialty product of different range

3. Fully Drawn Yarn

[11]

10. Barabanki

Barabanki Manufacturing Division is located near Lucknow, Uttar Pradesh. It

manufactures Black Fiber.

Barabanki Manufacturing Division was commissioned in January, 1987, with technical

collaboration from M/s. Du Pont, USA to manufacture 15,000 MT per annum of

Commodity Polyester Staple Fibre. The capacity was gradually increased to 30,000 MT

per annum by de-bottlenecking. The Commodity Polyester Staple Fibre produced was sold

in national and international markets.

In 2004, further capacity of 10,000 MT per annum was added by installing an extrusion

based Spinning Plant. With this addition the present installed capacity of Barabanki

Manufacturing Division is 40,000 MT per annum.

11. Silvassa

Reliance Silvassa Manufacturing Division is located in the Union Territory of Dadra and

Nagar Haveli. It manufactures a wide range of specialty products such as Recron Stretch,

Linen Like, Melange, Thick-n-thin and Bi-shrinkage yarns.

This division is the largest unit of it's kind in the world engaged in the field of texturizing

of polyester partially oriented yarn (POY) to produce a wide range of polyester textured

yarns (PTY) such as crimp, tex, intermingle in various deniers ranging from 30 D to 1200

D. The Denier per Filament (DPF) ranges from 0.5 to 4.8. It produces a wide variety of

specialty products such as Recron Stretch, Linen Like, Melange, Thick-n-thin and Bi-

shrinkage yarns. This division is the largest supplier of Recron stretch products to Denim

industry in India. Moreover, it also offers various tailor-made products to suit the specific

end use requirements. The textured yarn produced is used in suitings, shirtings, dress

materials, home furnishings and automotive fabrics.

This division has 158 state-of-the-art false twist texturising machines of Barmag, Murata,

TMT, ICBT, Himson and Alidhra makes. The installed capacity of division is 150 KTA

[12]

and it exports 25 % of its production to various high quality demanding advanced markets

of Europe, USA, North America, Far East and African markets to about 45+ countries.

This division enjoys various international certifications and accreditations such as ISO

9001, ISO 14001, OHSAS 18001 and Oekotex certificate for exports. To achieve continual

improvements and growth, the Division has also deployed Six Sigma & Quality Circle

activities in various functional areas.

This division offers the best quality products with a three tier quality assurance system. All

the machines are equipped with on line tension monitoring (OLT) system wherein every

meter of yarn is continuously monitored by computers for product quality during

texturising, itself.

The products deliver competitive edge to the customers by virtue of :

Equal length packages that minimize waste,

Uniform package density for consistent package unwinding at high speed,

Continuity of batch nos. to enhance productivity and reliability,

100 % transfer tail end to improve the machine efficiencies

12. Vadodara

Vadodara Manufacturing Division located in Vadodara, Gujarat. It comprises of a Naphtha

cracker and 15 downstream plants for the manufacture of polymers, fibers, fiber

intermediates and chemicals.

[13]

Introduction to Polymers Testing at PARC

Polypropylene

Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging and labeling, textiles (e.g., ropes, thermal underwear and carpets), stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids.

There are three general types of polypropylene: homopolymer, random copolymer, and block copolymer. The comonomer is typically used with ethylene. Ethylene-propylene rubber or EPDM added to polypropylene homopolymer increases its low temperature impact strength. Randomly polymerized ethylene monomer added to polypropylene homopolymer decreases the polymer crystallinity, lowers the melting point and makes the polymer more transparent.

Polymerization of propylene can yield any of the three polymer forms, isotactic, syndiotactic or atactic. Polypropylene has three basic polymeric forms: isotactic, syndiotactic and atactic. These different polymeric forms arise because, compared to the starting substance for polyethylene CH2=CH2 (ethene), the starting substance propylene CH3•CH=CH2 (propene), has a methyl (CH3) group in place of a hydrogen. In the isotactic form of polypropylene the methyl group has the same configuration at each tertiary carbon atom along the polymer chain. In the syndiotactic form, the methyl group alters position on alternative tertiary carbon atoms. In the atactic form, the methyl group takes up random positions on the tertiary carbon atoms.

[14]

Reliance Brand Name:Repol

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Industrial Process:

Traditionally, three manufacturing processes are the most representative ways to produce polypropylene.

Hydrocarbon slurry or suspension: Uses a liquid inert hydrocarbon diluent in the reactor to facilitate transfer of propylene to the catalyst, the removal of heat from the system, the deactivation/removal of the catalyst as well as dissolving the atactic polymer. The range of grades that could be produced was very limited. (The technology has fallen into disuse).

Bulk (or bulk slurry): Uses liquid propylene instead of liquid inert hydrocarbon diluent. The polymer does not dissolve into a diluent, but rather rides on the liquid propylene. The formed polymer is withdrawn and any unreacted monomer is flashed off.

Gas phase: Uses gaseous propylene in contact with the solid catalyst, resulting in a fluidized-bed medium.

Manufacturing:

Melt processing of polypropylene can be achieved via extrusion and molding. The most common shaping technique is injection molding, which is used for parts such as cups, cutlery, vials, caps, containers, housewares, and automotive parts such as batteries. The related techniques of blow molding and injection-stretch blow molding are also used, which involve both extrusion and molding.

Application:

Product Classification Features Uses

REPOL H110MA Homopolymer

Antistatic, Food contact Acceptable

Blending; Compounding, Containers, Furniture, Houseware

REPOLSRM100NC

Random copolymer

Antistatic; Food Contact Acceptable; High Clarity

Blow Molding Applications; Containers; Household Goods

REPOL H030SG Homopolymer

Food Contact Acceptable; Good Processability

Industrial Applications; Carpet Backing; Monofilament

[16]

REPOL H200MA Homopolymer

Antistatic; Food Contact Acceptable

Thin-walled Containers

REPOL B120MA Impact Copolymer

Food Contact Acceptable; General Purpose; Medium

Automotive Applications; Furniture; General Purpose

REPOL H100EY Homopolymer

Antiblocking; Food Contact Acceptable; General Purpose

Slip Bags; Film; Food Packaging; General Purpose; Packaging

REPOL SR20NC Random Copolymer

Food Contact Acceptable

Blow Molding Applications; Bottles; Containers

REPOL H034SG Homopolymer

Food Contact Acceptable

Pacific Bi-axially Oriented Film; Film; Food Packaging

Polyethylene

Polyethylene (abbreviated PE) or polythene (IUPAC name polyethylene or

poly(methylene)) is the most common plastic. Its primary use is in packaging (plastic bag,

plastic films, geomembranes, containers including bottles, etc.).

Polyethylene is classified into several different categories based mostly on its density and

branching. Its mechanical properties depend significantly on variables such as the extent

and type of branching, the crystal structure and the molecular weight. With regard to sold

volumes, the most important polyethylene grades are HDPE, LLDPE and LDPE.

[17]

Ultra-high-molecular-weight polyethylene (UHMWPE)

Ultra-low-molecular-weight polyethylene (ULMWPE or PE-WAX)

High-molecular-weight polyethylene (HMWPE)

High-density polyethylene (HDPE)

High-density cross-linked polyethylene (HDXLPE)

Cross-linked polyethylene (PEX or XLPE)

Medium-density polyethylene (MDPE)

Linear low-density polyethylene (LLDPE)

Low-density polyethylene (LDPE)

Very-low-density polyethylene (VLDPE)

Chlorinated polyethylene (CPE)

Reliance Brand Name:Relene

Application:

HDPE

[18]

Raschel bags for fruits and vegetables , containers for packaging edible oil, processed

food, carrier bags, pipes for water supply, irrigation.

LDPE

LDPE is widely used for manufacturing various containers, dispensing bottles, wash

bottles, tubing, plastic bags for computer components, and various molded laboratory

equipment. Its most common use is in plastic bags.Trays and general purpose containers

Corrosion-resistant work surfaces Parts that need to be weldable and machinable Parts that

require flexibility, for which it serves very well Very soft and pliable parts such as snap-on

lids, six pack rings

LLDPE

Filmsfor packaging milk, edible oil, salt, roto-molded containers for storage of water,

protective films and pipes for agriculture.

There are different grades that are produced by reliance. Some of the grades along with

their applicationsare given below.

Product Classification Features Uses

RELENE1005FY20 LDPE

FoodContact Acceptable;

Good Heat Seal; Good

Impact strength

Film; Packaging

RELENE1070LA17 LDPE

Contact Acceptable; Good

Adhesion; Good

Drawdown

Coating

Applications; Film;

Laminates

RELENE

1003FA20

LDPE

Food Contact Acceptable;

Good Impact Resistance

Agricultural

Applications; Film;

Shrink Wrap; Wire

RELENE54GB012 HDPE

Bimodal Molecular Weight

Distribution;

Containers;Blow

Molding;Foodcontact

RELENE

16MA400

LDPE Food Contact Acceptable Flow Masterbatch;

Thin-walled Parts

RELENE M60075 HDPE

Food Contact Acceptable;

Good Dimensional

Stability

Containers; Crates;

Industrial

applications;

[19]

Luggage

RELENE

1020FA20

LDPE Food Contact AcceptableFilm;

Laminates

RELENE 24FS040 LDPE

Contact Acceptable;

General Purpose

Food; High Slip

Bags; General

Purpose; Packaging

RELENE E52009 HDPE Food Contact Acceptable

Low Gel; Low Water

Carryover

Monofilaments; Tape

RELENE F19010 LLDPE

Antiblocking; Antioxidant;

ButeneComonomer

Food and film

Packaging

Polyvinyl Chloride

PVC comes in two basic forms: rigid (sometimes abbreviated as RPVC) and flexible. The

rigid form of PVC is used in construction for pipe and in profile applications such as doors

and windows. It is also used for bottles, other non-food packaging, and cards (such as bank

or membership cards). It can be made softer and more flexible by the addition of

plasticizers, the most widely used being phthalates. In this form, it is also used in

plumbing, electrical cable insulation, imitation leather, signage, inflatable products, and

many applications where it replaces rubber. Pure poly(vinyl chloride) is a white, brittle

solid. It is insoluble in alcohol but slightly soluble in tetrahydrofuran.

Polyvinyl chloride is produced by polymerization of the vinyl chloride monomer (VCM),

as shown.

[20]

About 80% of production involves suspension polymerization. Emulsion polymerization

accounts for about 12% and bulk polymerization accounts for 8%. Suspension

polymerizationsaffords particles with average diameters of 100–180 μm, whereas emulsion

polymerization gives much smaller particles of average size around 0.2 μm.

Chlorinated Polyvinyl Chloride (CPVC) is PVC (polyvinyl chloride) that has been

chlorinated via a free radical chlorination reaction. This reaction is typically initiated by

application of thermal or UV energy utilizing various approaches. In the process, chlorine

gas is decomposed into free radical chlorine which is then reacted with PVC in a post-

production step, essentially replacing a portion of the hydrogen in the PVC with

chlorine.CPVC shares most of the features and properties of PVC. It is also readily

workable, including machining, welding, and forming. Because of its excellent corrosion

resistance at elevated temperatures, CPVC is ideally suited for self-supporting

constructions where temperatures up to 200 °F (90 °C) are present.

Reliance Brand Name:Reon

Application:

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Pipes and fittings, Door and window profile, rigid bottles and containers for packaging

applications, footwear, flooring & blood bags. The uses of different grades of REON are

Product Classification Features Use

Reon 67-01 PVC Homopolymer

Good Processability;

Homopolymer;

Medium Molecular

Weight

Film; Piping;

Profiles; Sheet

Reon 57GMR01 PVC Homopolymer

Low Molecular

Weight; High Flow;

Homopolymer

Foam; Handles;

Piping; Sheet



High Flow;

Homopolymer; Low

Molecular weight

Bottles; Cosmetics;

Film; Handles;

Packaging; Piping;

Sheet



Homopolymer; Low

Molecular weight

WeightBottles;

Containers;

Cosmetic

Packaging;

Cosmetics


Food Contact

Acceptable; High

Flow; Low molecular

weight

Containers; Foam;

Foamed Insulation

Board

Reon 57GER01 PVC Homopolymer


High Flow;

Homopolymer; Low

Molecular weight

Bottles; Containers;

Cosmetics; Film;

Foam; Handle



HighFlow;

Homopolymer;Medium

molecular weight

Film; Piping;

Profiles; Sheet



High Flow;

Homopolymer; Low

Bottles; Cosmetic

Packaging;

Cosmetics; Film;

[22]

Molecular weight Packaging

Reon 67GEF01 PVC Homopolymer

Food Contact

Acceptable;

Homopolymer;

Medium Molecular

weight

Cable Jacketing;

Footwear; Hose;

Insulation; Medical

application

Reon 67-11 PVC

Homopolymer

Food Contact

Acceptable;

Homopolymer;

Medium Molecular

Cable Jacketing;

Film; Footwear;

Hose;

Insulation;...View

entire Reon product

line.

Plants of Reliance where Polymers aremanufactured

Polypropylene

Type of Polymer manufactured

Plant Sites

HP,ICP HaziraHP Jamnagar DTAHP Jamnagar SEZHP,RCP,ICP NarodaHP,RCP Nagothane

Polyethylene


Plant Sites

[23]

LDPE Baroda

NagothaneHDPE Gandhar

EVALLDPE/HDPE Swing Nagothane

Hazira

Polyvinyl chloride


Plant Sites

PVC Hazira, Baroda &Gandhar

[24]

4. INTRODUCTION TO PRODUCT APPLICATION & RESEARCH CENTRE

The product application & research centre (PARC), Reliance Industries Limited

petrochemical division was established in 1990 at Chembur, Mumbai as a technical wing

of the polymer marketing division. It is deeply involved in the development of new grades

& the optimization of the existing grades in terms of cost & properties. It also carries out

continuous valuation of various lots produced at Jamnagar &Hazira plants. PARC is

committed to deliver value addition to polymer business of Reliance Industries Limited by

providing technical service, constant product up gradation and initiating market

development with the sole objective of total customer satisfaction. It also carries out

testing and trials of various modified and developmental grades.

PARC is a conduit between business enterprises and their vendors, converting basic needs

into commercially viable technology and helping to produce useful products. To fulfill

these objectives, sophisticated analytical & processing facilities have been established at

PARC.

PARC is recognized by the department of science and industrial research as an in-house

research & development wing of reliance-plastic & petrochemical division.

Functions of PARC:

Product development

Process development

Customer Support / Technical service

Co-ordination with plant & marketing department for benchmarking exercises

Training & manpower development

The Activities of PARC can be divided into:

Testing

Processing

[25]

5. TESTING DIVISION

Testing of raw material is absolutely necessary for quality control &

characterization. The analytical laboratory is involved in the analysis & testing of resin and

product samples received from the customers as well as from the PARC division.

Testing for resin: Melt Flow Index

Ash Content

Bulk Density

FTIR Spectroscopy

Measurement of Color

Differential Scanning Calorimeter

Thermo Gravimetric Analysis Density

Testing for plastic films: Shrinkage Test for films Tear Strength Coefficient of Friction (COF) Haze Dart Impact Strength Tensile Properties

Haze test

Testing for Molded samples: Tensile properties

Scanning Electron Microscope(SEM)

Izod-Impact strength

Shrinkage Test

Heat Deflection Temperature &Vicat Softening point

Environmental Stress Cracking Resistance (ESCR)

Specular Gloss Testing

[26]

Indentation Hardness Testing

Flexural Properties of Plastics

Gardener Impact Resistance

[27]

TESTING FOR RESIN

Melt Flow Index Determination

Reference: ASTM D1238

Machine Make: Davenport Flow Indexer.

Summary: For this, molten polymer is extruded through a die and flow of polymer ismeasured under a specified load and at particular temperature per 10 min

Scope: This procedure is used to determine melt flow properties of resins with the help ofDavenport Flow Indexer. Melt Index is an inverse measure of molecular weight. Sinceflow characteristics are inversely proportional to the molecular weight, a low molecular polymer weight polymer will have a high melt index value and vice versa.

Principle: MFI indicates the rate of extrusion of molten resin through a die of specified length and diameter under prescribed conditions of temperature,load and piston position in barrel.

[28]

Apparatus: (I) Melt Flow Indexer (Davenport make) with accessories:

Temperature: PE: 1900C

PP: 2300C

Preheating time :

o PP: 6 min

o PE:5 min

Barrel diameter= 9.5504 ±0.0016 mm

Die diameter= 2.0955 ± 0.0016 mm

Die Length= 8 ± 0.025 mm

Weight= 2.16 kg, 6.48 kg (± 0.5% of the total weight)

Procedure:

1. Manual

A small amount of the polymer sample (around 4 to 5 grams) is taken as per the expected MFI of material in the specially designed MFI apparatus. The apparatus consists of a small die inserted into the apparatus, with the diameter of the die being around 2 mm.

The material is packed properly with the help of suitable piston inside the barrel to avoid formation of air pockets.

A piston is introduced which acts as the medium that causes extrusion of the molten polymer.

The sample is preheated for a specified amount of time: 5 min at 190°C for polyethylene and 6 min at 230°C for polypropylene.

Push the piston a little above the mark to ensure good packing (known as purging).

After the preheating a specified weight is introduced onto the piston. Examples of

standard weights are 2.16 kg, 5 kg, etc.

The weight exerts a force on the molten polymer and it immediately starts flowing

through the die.

A sample of the melt is cut in regular intervals of time and is weighed accurately.

MFI is expressed as grams of polymer/10 minutes of flow time.

[29]

2. Automatic

Weigh the specimen and put it in the apparatus as per the expected MFI.

Select remote control on apparatus and start the computer.

In the computer start console software.

Feed polymer type, melt density, cut-off length and file name.

Start the test.

Purge after 3 minutes just before the mark on piston.

Put the arrester of 71mm or 81mm height depending on whether the material is Hi-Flow or Low-Flow.

Put the weight on plate above the apparatus. Record the output.

ASH CONTENT

Reference: ASTM D2584, D5630

Machine Make: Mettler Balance, Bunsen burner

Scope: This test is used to find out the inorganic residues in a polymer sample by ashing it in a muffle furnace.

[30]

Summary: A weighed amount of sample is heated to 850±10⁰C and residue after treating is expressed in terms of % ash content.

Principle: The organic matter in a polymer sample is burnt at 850±10⁰C until constant mass of inorganic matter is obtained.

Apparatus: 1. Weighing balance 2. Silica crucible 3. Bunsen burner 4. Silica triangle & tripod 5. Holder

Sample specification: 3-5 g of sample

Procedure

The sample weight and the weight of the empty crucible are noted.

Sample is put in the crucible and allowed to burn till it becomes completely black and the organic materials have vanished.

In case of PVC sample (self-extinguishing in nature) the sample is now wetted completely with 98% sulphuric acid and it is again heated to give out CaSO4.

After heating, the PVC sample is now put in the oven for 1 hour at 850°C.

For other samples, after burning is completed they are put in an oven maintained at 550°C

Now the sample is kept in a desiccant (containing silica gel) for ½ hour to absorb

all the moisture.

It is then weighed and the ash content is found.

Calculation

% ash content = Weight of ash × 100 Weight of sample

NOTE: WITH THE HELP OF STOICHIOMETRY WE CAN EASILYCALCULATE

THE WEIGHT OF FILLER CONTENT. FILLER CONTENT MEANS MIXTURE OF

CALCIUM CARBONATE AND MAGNESIUM SULPHATE(TALC).HEATING AT

[31]

850°CWILL HAVE NO EFFECT ON MAGNESIUM SULPHATE WHEREAS

CALCIUM CARBONATE DECOMPOSES INTOCALCIUM OXIDE AND GAS IS

RELEASED. WITH THE HELP OF CALCIUM OXIDE CONTENT LEFT WE CAN

EASILY CALCULATE THE AMOUNT OF CALCIUM CARBONATE PRESENT

INITIALLY.

Fourier Transform Infrared Spectroscopy (FTIR)

Reference: ASTM E1252

Machine make-Perkin Elmer, spectrum 100 series

Principle:

[32]

FTIR utilize an ingenious device called Michelson interferometer, which was developed

many years ago by A. A. Michelson for making precise measurement of the wavelengths

of electromagnetic radiations.

FTIR instruments contain no dispersing elements and all wavelengths are detected and

measured simultaneously. Instead of a monochromator an interferometer is used to

produce interference patterns that contain the infrared spectral information.

In FTIR when an infrared spectrum is introduced to a sample stretching and bending of

various bonds takes place and due to different bond energies, each molecule absorbs

energy at a different frequency.

One of the components of an electromagnetic wave is a rapidly reversing electric field

(E). This field alternately stretches and compresses a polar bond. When the electric field is in the

same direction as the dipole moment, the bond is compressed and its dipole moment decreases.

When the field is opposite the dipole moment, the bond stretches and its dipole moment increases.

If this alternate stretching and compressing of the bond occurs at the frequency of the molecule's

natural rate of vibration, energy may be absorbed. The energy is absorbed by a molecule only when

there is a change in dipole moment.

[33]

The Source: Infrared energy is emitted from a glowing black-body source. This

beampasses through an aperture which controls the amount of energy presented to the

sample (and, ultimately, to the detector).

The Interferometer: The beam enters the interferometer where the “spectral encoding”

takes place. The resulting interferogram signal then exits the interferometer

[34]

The Sample: The beam enters the sample compartment where it is transmitted throughor

reflected off of the surface of the sample, depending on the type of analysis being

accomplished. This is where specific frequencies of energy, which are uniquely

characteristic of the sample, are absorbed.

The Detector: The beam finally passes to the detector for final measurement. Thedetectors

used are specially designed to measure the special interferogram signal.

The Computer: The measured signal is digitized and sent to the computer where

theFourier transformation takes place. The final infrared spectrum is then presented to the

user for interpretation and any further manipulation.

Procedure:

Take small amount of material on a glass slide and place it on a hot plate. Ensure

the material melts and press it into a uniform film by applying steady pressure by

means of another glass plate. If material is already in film form it can be used

directly.

Once the background scan has been completed the spectroscopy of the material is

carried out.

Place the film sample on the Universal Attenuated Total Reflectance Cell and scan

it for background radiation.

The interference pattern of the material is obtained which is converted by the

Fourier analyzer into a spectrum.

The graph obtained is of % transmittance v/s wave number.

[35]

(A typical FTIR spectrum)

NOTE: WE NEED TO DO BLANK FTIR FOR THE DETECTON OF NOISE PRODUCED DUE TOAIR (BACKGROUND DISTURBANCES) BEFORE PERFORMING FTIR FOR THE CHEMICAL COMPOUND. LATER, AREA OF THE PEAKS DUE TO NOISE IS SUBSTRACTED WITH THE RESULT TO FIND OUT THE DISTURBANCES DUE TO SAMPLEONLY.

[36]

DIFFERENTIAL MECHANICAL ANALYSIS

REFERENCE: ASTM D-5279/D-4065

SCOPE: Studying viscoelastic behavior of polymers , glass transition temperature.

SUMMARY: a sinusoidal stress is applied and the strain in the material is measured

allowingone to determine the complex modulus.The temperature of the sample or the

frequency of the stress are often varied , leading to variations in the complex modulus.

NOTE: IT IS 10 TO 100 TIMES MORE SENSITIVE THAN DSC FOR THE

MEASUREMENT OF GLASS TRANSITION TEMPERATURE. IT ALSO

MEASURES STIFFNESS AND DAMPING REPORTED AS MODULUS AND TAN

DELTA RESPECTIVELY.

THEORY:

Polymers composed of long molecular chains have unique viscoelastic properties, which

combine the characteristics of elastic solids and Newtonian fluids. The classical theory of

elasticity describes the mechanical properties of elastic solid where stress is proportional to

strain in small deformations. Such response of stress is independent of strain rate. The

classical theory of hydrodynamics describes the properties of viscous fluid, for which the

response of stress is dependent on strain rate. This solidlike and liquidlike behavior of

polymer can be modeled mechanically with combinations of springs and dashpots

[37]

INSTRUMENTATION:

The instrumentation of a DMA consists of a displacement sensor such as a linear variable

differential transformer, which measures a change in voltage as a result of the instrument

probe moving through a magnetic core, a temperature control system or furnace, a drive

motor (a linear motor for probe loading which provides load for the applied force), a drive

shaft support and guidance system to act as a guide for the force from the motor to the

sample, and sample clamps in order to hold the sample being tested. Depending on what is

being measured, samples will be prepared and handled differently.

Temp range : -190 to 400 °C

Sample size maximum: 52.5(mm)* 12.8(mm)* 8 (mm)

APPLICATION:

One important application of DMA is measurement of the glass transition temperature of

polymers. Amorphous polymers have different glass transition temperatures, above which

the material will have rubbery properties instead of glassy behavior and the stiffness of the

material will drop dramatically with an increase in viscosity. At the glass transition, the

storage modulus decreases dramatically and the loss modulus reaches a maximum.

[38]

Temperature sweep:

A common test method involves measuring the complex modulus at low constant

frequency while varying the sample temperature. A prominent peak in appears at the glass

transition temperature of the polymer. Secondary transitions can also be observed, which

can be attributed to the temperature-dependent activation of a wide variety of chain

motions. In semi-crystalline polymers, separate transitions can be observed for the

crystalline and amorphous sections. Similarly, multiple transitions are often found in

polymer blends.

For instance, blends of polycarbonate and poly(acrylonitrile-butadiene-styrene) were

studied with the intention of developing a polycarbonate-based material without

polycarbonate’s tendency towards brittle failure. Temperature-sweeping DMA of the

blends showed two strong transitions coincident with the glass transition temperatures of

PC and PABS, consistent with the finding that the two polymers were immiscible.

Figure shows Storage modulus and loss modulus against Temperature were

plotted.

[39]

Determination of Density


Scope: This test is used to measure the density of solid samples.

Principle: Archimedes Principle

Apparatus:

Weighing Balance (METTLER )

Density meter assembly: Beaker stand, Beaker (500mL), a frame attached to the

weighing pan and a sample holder which facilitates weight in air and in liquid.

Chemicals Used: 1. n-butyl acetate

2.DM Water

[40]

NOTE: BUTYL ACETATE IS USED IN PLACE OF WATER BECAUSE IT HAS

DENSITY OF 0.88 g/L AT ROOM TEMPERATURE. SINCE IT IS NECESSARY

FOR POLYMER TO SINK IN IT FOR DENSITY DETERMINATION AND ALL

POLYMERS HAVE DENSITY GREATER THAN 0.88 g/L, BUTYL ACETATE IS

IDEAL FOR THIS USE.

Sample Specification:1 cm x 1 cm smoothly cut sample is used for densitydetermination.

The sample shouldnot have any sharp edges.

Procedure:

The weight of the sample was measured in air and then in a liquid (n-butyl acetate) of

known density. The density of the liquid used was less than the expected density of the

sample. The ratio of weight in air to loss of weight in liquid was used to calculate the

density of the sample.

Calculation:

Density of sample at Tm =Wa

ρ sWa̵ Ws

Where:

Tm = Temperature of measurement

Wa = Weight in air

Ws = Weight in the liquid

ρs = Density of the liquid at Tm

[41]

Determination of Tear Strength of films


Machine Make: CEAST Italy

Scope: Used to measure the tear strength of plastic films.

Summary: To force to propagate a tear across a film or sheeting specimen is measured

using a constant rate of grip separation machine.The force necessary to propagate the

tear is interpreted from the load time chart.

Principle:

The force to propagate a tear across a film or sheeting specimen is measured. The force

necessary to propagate the tear is measured.

Apparatus: CEAST ED 30 machine, Digital micrometer

Sample Specification:

The specimens shall be of the single tear type and shall consist of strips 76 mm long by 64

mm wide. The thickness of the specimen is noted along the path where tear will occur. The

samples are cut in the machine direction (MD) and the transverse direction (TD).

Procedure: Different weights available are 4000mN, 8000mN, 16000mN,

32000mN,64000mN, 50N, 100N. The weight is selected such that the film reading lies

between 20-90% of the weight. The blank reading is taken and the machine is calibrated.

The sample is inserted in the pneumatic sample holder. The cover is shut and the film

tears. The reading is noted from the display.

Calculation: Tear Strength (in g/µm) = Force in cN / thickness (µm)

[42]

NOTE: TEAR STRENGTH IN MACHINE DIRECTION IS ALWAYS LESS THAN

TRANSVERSE DIRECTION BECAUSE MOLECULES ARE ALIGNED IN

MACHINE DIRECTION. SO IT IS EASIER TO SEPARATE DIFFERENT

CHAINS (M.D) THAN TO BREAK BONDS OF CHAINS (T.D).

Determination of Coefficient of friction of Plastic

Films


Machine Make: Davenport

Scope: Used to find coefficient of friction between a plastic film with respect to otherfilms and metal surfaces.

Summary: Two surfaces are made to slide against each other and the force required for this is measured.

Principle:

Frictional force f is related to the normal force acting on a body at rest as follows: f=µN, where µ is the coefficient of friction. The COF associated with the force required to start a body from rest is known as coefficient of static friction and that associated with a moving body is known as the coefficient of kinetic friction.

Apparatus: Davenport friction measuring apparatus, template, vacuum pump

Sample Specification: 675 mm x 255 mm should be attached to the testing plane and 6.5mm x 6.5 mm minimum for sliding.

[43]

Analytical Procedure:

The vacuum is switched on and the film is placed on the plane, without wrinkles. The film

is attached to the 200g sled with cellophane tape taking care to avoid wrinkles. The cord is

attached to the sled and placed gently on the plane at two fixed points parallel to the

machine direction. The speed is selected to be 15 cm/min. There should be no tension in

the cord and both the force meter displays are zero. The first reading as soon as the cord

pulls the slab is the static friction. The reset button is then pressed to get the value of the

kinetic friction.

Calculation:

COSF = Static force/ weight of the sled=SF/20

COKF = Kinetic force/ weight of the sled=KF/20

NOTE: IT IS EASIER TO BREAK IN MACHINE DIRECTION THAN IN TRANSVERSE DIRECTION.

Determination of Dart Impact Strength for Plastic Films

[44]


Apparatus: Dart Impact Testing apparatus (International Engineering Industries), Weights

Scope: Used to measure the dart impact strength of plastic films

Summary: Darts of various weights are made to fall on a clamped film and the weight at

which 50% of the samples fail is measured.

Sample Specification: Greater than the diameter of the specimen holder

Principle:

Dart Impact strength values are very important for plastics packaging. They theoretically

give the impact strength of the plastic film. In the test, falling weights from a specified

height are made to fall on the film until fracture occurs. The weight at which 50% of the

samples fail is the dart impact weight value. This value divided by thickness in microns

gives dart impact strength.


The two different types of dart used are:

A.38.1 ± 0.13 mm of 55g weight

B.50.8 ± 0.13 mm of 283g weight Vacuum applied is 700 mm of Hg

A. Dropped from 66 cm and is used for films requiring masses of about 50g to 2 kg to

fracture

B. Dropped from 152 cm and used for films requiring masses of 0.3 to 2 kg to fracture

10 samples are tested on each weight level and the weight at which 50% failure occurs is

reported.

[45]

Calculation:

Dart Impact Strength (g/µm) = Weight to cause 50% fracture (g)/ thickness (µm)

Determination of Tensile Properties of Plastic Films


Machine make:Lloyd, LRX plus

Scope:This test method covers the determination of tensile properties of plastics in the

form of thin sheeting, including film (less than 1.0 mm (0.04 in.) in thickness).

Sample specifications: The width of the sample should be 15 mm - 25 mm and the

gaugelength should be 5 cm.

SPEED OF CROSSHEAD : 500mm/min

Principle:

Plastic products when subjected to tensile force initially resist deformation, get elongated

and finally break. Tensile elongation and tensile modulus measurements are amongst the

most important indications of strength in a material and are the most widely specified

[46]

properties of the plastic materials. Tensile test, in a broad sense, is a measurement of the

ability of the material to withstand forces that tend to pull it apart and to determine to what

extent the material stretches before breaking. Tensile modulus, an indication of the relative

stiffness of a material can be determined from a stress-strain diagram.

Procedure:

The film is cut in exact dimensions making sure that the sides are uniform. The sample is

clamped carefully and the thickness of the film is measured using a digital micrometer.

The dimensions and batch references are entered in the software. The initial load is tare

and the speed of testing is set to 500 mm/min and the machine is started. The stress vs.

extension curve of the specimen is recorded and the required values are taken.

NOTE: TENSILE STRENGTH IN MACHINE DIRECTION IS ALWAYS MORE

THAN IN TRANSVERSE DIRECTION BECAUSE MOLECULES ARE ALIGNED

IN MACHINE DIRECTION. SO IT IS DIFFICULT TO BREAK BONDS OF

CHAINS (IN M.D) THAN TO SEPARATE DIFFERENT CHAINS (IN T.D)

Haze Test

Reference: ASTM D 1003

[47]

Scope: This test is used to measure the haze (% Transmittance) of plastic films and sheets

Principle: The haze is determined by percentage of light scattered from the product.

The haze of the specimen is the percentage of transmitted light which is passing through

the specimen deviates from the incident beam by forward scattering.For the purpose of this

method only light flux deviating more than 2.5’ on the average is considered to be haze

The haze can be inherent in the material,a result of the moldingprocess,or a result of

surface texture.

Haze can also be a result of environmental factors such as weathering or surface abrasion.

Sample: Size suitable to cover the port.

Procedure:

The instrument is calibrated before haze measurement in the Total Transmittance

Mode

The mode “large area view “ and “UV filter out” are selected

The blank reflectance trap is placed against the receptor lens and the machine is

allowed to read.

The white tile is placed in the reflectance port and the transmittance compartment

is kept away.

The sample holder is placed against the sphere and the machine is allowed to read.

Instrument is now ready for haze measurement.

[48]

TESTING FOR MOLDED SAMPLES

Determination of Tensile Properties of Molded Plastics


Scope: This test is used to determine the tensile properties of molded polymer samples.

Summary: Standard molded specimens were exposed to tension and force required to elongate and break the specimen of elongation were observed.

Principle:

Plastic products when subjected to tensile force initially resist deformation, get elongated

and then finally break. Tensile elongation and tensile modulus measurements are among

the most important indications of strength in a material and are most widely specified

properties of plastic materials. Tensile test in a broad sense is a measurement of the ability

of a material to withstand forces that tend to pull it apart and to determine to what extent

the material stretches before breaking. Tensile modulus, an indication of the relative

stiffness of a material can be determined from a stress-strain diagram.

[49]

Apparatus:

(i) Universal Testing Machine

(ii) Grips for mounting the specimen

(iii) VernierCalipers

Sample Specification: Five specimens are tested as per the following specifications:

Sample PE PP

Sample Type ASTM D638 Type IV Type I

Grip separation rate 50mm/min 50 mm/min

Distance between the grips 64 ± 5 mm 114 ± 1 mm

Procedure:

The testing machine is switched on and the program for determining the tensile properties

is selected. Test samples, previously conditioned are used for testing. Two marks, 1.0,0.1

inches apart are on all the test samples at the center of the narrow portion of the sample.

The width and thickness of the sample is measured to the nearest 0.001 mm and entered as

data. The specimen is placed in the grips of the testing machine and the grips are tightened.

The extensometer is then attached on the marks made on the sample. The initial load is

tare. The speed of the testing machine is set and the machine is started. The load vs.

extension curve of the specimen is recorded and the load and extension at the yield point

and the point of rupture are noted. Tensile strength at yield (TYS), UTS, % elongation at

break and % elongation at yield were directly displayed on the screen.

[50]

Calculations:

Tensile modulus was calculated from the points on the stress-strain curve

Tensile Modulus = Difference in stress/difference in corresponding

Strain Tensile strength= force/ area

Determination of Izod-Impact Strength of

Plastics

[51]


Machine Make: ResilImpactor

Scope: This procedure is used to determine the impact strength of molded polymersamples.

Summary: Notched specimens were subjected to impact with the help of a strikingpendulum hammer. Energy required for the sample to break was noted.

Principle:

Impact test indicates the energy required to break standard test specimens of a specified

size. Energy lost by the pendulum during the breaking of the specimen was noted.

The objective of the Izod Impact test is to measure the relative susceptibility of a standard

test specimen to the pendulum-type impact load. The results are expressed in terms of

energy consumed by the pendulum in order to break the specimen. The energy required to

break a standard specimen is actually the sum of the energies needed to deform it, to

initiate its fracture and to propagate the fracture across it, and the energy needed to throw

the broken ends of the specimen.

Apparatus:

Izod Impact Tester- CEAST (Resil-25)

Notch cutter with micrometer-screw gauge

Vernier Calipers- Accuracy 0.01 mm

[52]

Notch cutter

Sample specification: Molded specimens have width between 3.17 and 12.7 mm.

Thedepth of the plastic material remaining in the bar under the notch was 10.16 ± 0.05 mm

and the distance of the notch from the end was between 31.5 to 32 mm.


1. Hammer was selected along with the relevant range and installed by means of the range selector and the range switch.

2. The hammer was manually checked so as to ensure that it could be swung freely between the anvils.

[53]

3. The hammer was initially released without the specimen and the value displayed indicated the amount of energy lost due to friction, wind age, and other factors.

4. This value was subtracted from each of the final sample readings.

5. The hammer was positioned on the anvil and the test samples (conditioned for 40 hours at 23±2 °C) were positioned and tightened with the torque wrench.

6. The hammer was then released and the breaking energy value on the digital display was noted down.

7. If the display exceeded 70% of the 2.75 J, then the hammer was replaced by a higher energy hammer and the above steps were repeated again.

Calculation:

Izod Impact Energy required to break the specimen – Air resistance

Energy = Thickness

Shrinkage Test


Scope: This test method is intended to measure shrinkage from mold cavity to moldeddimensions of thermosetting plastics when molded by compression, injection, or transfer under specified conditions

Principle:

Plastic products have a tendency of shrinking when they once they are cooled down in the

mold. This happens as the polymer coming from extruder is highly stressed and upon

cooling the polymeric chains relieve their stress by orienting themselves randomly. This

random orientation leads to shrinkage of polymer. The shrinkage is more in case of

crystalline polymers as compared to amorphous polymers due to closer packing of chains.

[54]

Apparatus:

(i) VernierCalipers

Sample Specification: Standard mold dimension

Procedure:

We take a standard circular molded specimen.

The diameter of the specimen is measured.

The diameter of the mold is measured.

The % change is reported as shrinkage

Determination of Heat Deflection Temperature and Vicat SofteningPoint

Reference:HDT: ASTM D 648

Vicat Softening: ASTM D1525

[55]

Scope: This procedure is used to determine the heat deflection temperature and Vicatsoftening point of the polymer.

Summary:

HDT of a polymer is the temperature at which a specimen deflects by 0.25 mm at a specified stress of 455kPa or 1820kPa.

VICAT softening point is the temperature at which a flat ended needle of 1 mm2 surface area penetrates into the sample to a depth of 1 mm under 1 kg or 5 kg load.

Principle:

A molded, rectangular sample is placed in a temperature-controlled bath. The temperature

of the bath is increased at a constant rate. Mechanical properties of polymers are

temperature dependent.

Both HDT and VST have their own purposes i.e. when the softening temperature of a

polymer under stress is to be found the HDT test is used.

However, when the softening temperature of a plastic without any stress (say when it is

held by a support) is to be found VSP is used.

Apparatus:

Specimen supports: 100 mm apart

Immersion bath: 6-station HDT-Vicat testing machine capable of providing a

heating rate of 2±.0.2⁰C/ min. (make: CEAST)

Deflection measurement device: Accuracy = 0.01 mm

Weights: Set of weights to provide maximum fiber stress of 1820 kPa (264 psi) ±

2.5% or 455 kPa (66 psi) ± 2.5%

Working thermometer

Calibration:

[56]

Working thermometer is calibrated as per standard method.

Sample: Injection molded samples of the following dimensions are employed:

Dimension Heat Distortion Temperature Vicat Softening Point

Length 110 – 130 mm 1cm

Depth 13 ± 0.13 mm 3 – 13 mm

Width 3.2 mm 10mm

(I) Heat Distortion Temperature (HDT)

The test assembly was taken out from the bath and supported with a moving support. The

test heads were fitted below the rods using the keys and the gauge block provided.

According to the specimen dimensions the weight to be applied was calculated using the

following formula:

P=2bh2σ

3L

P = weight to be applied in KN

σ = Maximum fiber stress in the specimen

b = width of the specimen in mm

h = depth of the specimen in mm

L = Support span in mm

134.2g (the combined weight of the testing head, loading rod assembly, dial gauge and

cylindrical support fixed by the grub screw) were subtracted from the calculated weight

and then this weight was made up with the auxiliary weights provided. The Bakelite nut

was loosened and the indicator was moved sideways. The weights were placed on the load

rod and the indicator was returned to its original position and the Bakelite nut was

[57]

tightened. Test samples, previously conditioned at 23±2 ⁰C for 48 hours were placed on

the round supports. The loading unit was lowered by rotating the lever so that the HDT

head rested on the specimen. Springs were inserted to avoid the specimen from dropping

into the tank. The test assembly was then lowered by removing the moving support.

The test start preset was subsequently adjusted to 23-25⁰C and the test end preset to a

temperature 10-15⁰C higher than the expected HDT of the sample. The main switch was

switched in and the heater switched on about 30 seconds later. The zero was adjusted on

the indicator by loosening the block ring, after the heater switch started blinking (allowing

5 minutes as thermo station time) and the regulator screw was rotated such that the LED of

the corresponding station was switched off. The heating was then started. When the

required deflection was reached the instrument read the recorded value.

Sample orientation in HDT

[58]

(ii) VICAT softening Point (VSP)

The procedure was same as that of HDT except for the following:

The Vicat test heads were fitted instead of the HDT heads. The weight was place on the

Vicat head assembly totally amounting to 1000g (including the weight of the assembly i.e.

134.3g). The preset was testing started, set at least 50± 2 °C lower than the expected VSP

of the sample. The deflection on the gauge is adjusted to 1 mm. The tester was then

started. When the deflection on the gauge reached 1 mm, the instrument recorded that

temperature as the VSP of the sample.

Sample orientation in VST

[59]

Determination of Flexural Properties of Plastics


Scope: This procedure is used to determine the flexural properties of plastic materials

Summary: A sample was placed on a support span and subjected to flexural stress by a

loading nose and from the deflection data, flexural properties were determined.

Principle: Plastic Products when subjected to flexural strain resist deformation.

Flexuralstrength is the ability of the material to withstand bending forces applied

perpendicular to its longitudinal axis. The stresses induced due to the flexural load are a

combination of compressive and tensile stresses. Flexural properties are reported and

calculated in terms of the maximum stress and strain that occur at the outside surface of

the test bar. Many polymers do not break under flexure even after a large deflection that

makes determination of the ultimate flexural strength impractical for many polymers.

Apparatus:

(i) Universal Testing Machine (Lloyd)

(ii) Loading noses and supports

(iii) VernierCalipers (Mitotoyo make)

[60]

Sample specification:

Five samples of the following dimensions are tested:

Length = 127 ± 5mm

Width = 12.7 ± 1mm

Thickness = 3.2 ± 0.4 m

Support span length is 16 times the specimen thickness (Tolerance +4 or –2 mm)


An appropriate load cell (depending upon the type of material) is mounted on the machine.

The loading nose is attached to the load cell and the supports to the stationary crosshead.

The parallel alignment of the loading nose and supports is critical here. The machine is

switched on and the following instrumental parameters are set:

Speed of testing for the PP samples = 1.3 mm/min

The appropriate program for flexural properties is selected. Previously conditioned

(Maintained at 23 ± 2°C for 40 hours) test specimens are used. The width and thickness of

the samples being tested are entered as data and the support span is set at 50 ± 2mm for

PP. The specimen is entered on the supports. The experiment was performed and the load

deflection curve was displayed and the program gave the flexural yield strength, modulus

of elasticity, and 1% secant modulus directly.

Calculation:

Eb=L3F/ (4bh3Y)

σf =3FL/ (2bh2)

F: Force @ midpoint

L: Span

b: Width

h: Thickness

[61]

Measurement of Colour of Plastics

Reference: ASTM E313

Machine make: Color quest II, Hunterlab

Scope: This test is used to measure the L*, a*, b* values of the given sample and also theYellowness Index, Whiteness Index, and color differences between the standard and sample.

Sample specifications: Typically a 50 mm (2") or 100 mm (4") disk, although any flatsample that the specimen holder will grasp can be tested.

Procedure:

The instrument is first standardized for color measurements and the instructions in

the computer are followed to get the required values.

L* indicates brightness,

a* indicated greenness or redness,

b* indicates blueness or yellowness.

ΔE= ((∆L* )2 + (∆b* )2 + (∆a* )2 )

Standardization includes selection of specular reflectance mode with large area of

view and UV filter out.

[62]

The standard light trap is then inserted followed by the standard white and the

standard gray tiles.

The test sample is inserted into the specimen holder, and the spectrophotometer

takes the reading

The result obtained is in the form of L, a, b values, whiteness index (WI) and

yellowness index (YI).

Color analysis can be used to match adjacent parts molded from different materials, or to

evaluate color change due to outdoor exposure. Visual color and Spectrophotometer

readings can also be affected by surface texture, molding parameters, processing method,

and viewing light sources.

Gardener Impact Test


Scope: This method covers the determination of the relative ranking of materialsaccording

to the energy required to crack or break flat, rigid plastic specimens under various

specified conditions of impact of a striker impacted by a falling weight.

[63]

Summary: The procedure determine the energy (mass*gravity*height) that will cause50%

of the specimens tested to fail called as mean failure energy (MFE). For low temperature

cryo-test air chamber, condition the specimen for minimum 3 hours, once the required sub-

zero temperature is reached, carry out the test accordingly.

Principle: Energy of the falling weight at the instant of impact is kinetic energy which

isequal to the energy used to raise the weight to the height of the drop. It is the potential

energy possessed by the weight the instant it is released. Since the potential energy is (m x

g x h), the guide tube can be marked with a liner scale showing the impact range of the

instrument. Purpose of the impact testing is to find the amount of energy necessary to

cause failure of specimen and to establish a standard for impact resistance, and test

samples of the product against the established standard. Nature and extent of impact

damage that constitutes failure must be established, variables such as material thickness,

specimen shape, end use of the product are factors for evaluation. Once the failure point

has defined, the actual test program can be developed (i.e. number of specimens to be

impacted and what energy to use with each impact.

Apparatus: Gardner impact tester consist of a Cast Al base, a slotted vertical guide

tube,round nosed punch(up) and punch holder, 8 – lb. weight (3.6kgs), die and die support

(anvil) and a cryo-test air chamber (low temperature) a separate attachment.

Nose of the punch: - 0.600” (1.37cm) dia.;

Inside diameterof the die: - 0.640” (1.64cm);

Height of the guide tube: - 40” (101.6cm);

Scale graduation: - 0 to 320inch-pound

Specimen size: - Diameter = 100mm, Thickness = 3.2mm

Procedure:

Determine the number of specimens for each sample to be tested.

[64]

Place the test specimen on the tester anvil, after raising the weight and striker foot.

Be sure the specimen is flat against the specimen support plate before the striker

foot is brought in contact with the top surface of the specimen.

Raise the weight in the tube to the desired impact value as shown on the scale, and

release it so that the weight drops on the striker.

Remove the specimen and examine it to determine whether or not it has failed.

Permanent deformations alone are not considered failure, but note the extent of

deformation (depth, area).

In the first specimen fails, decrease the drop height while keeping the mass constant. If the

first specimen does not fail, increase the drop height one increment and then testthe second

specimen.

In this manner, select the impact height for each test from the results observed with the

specimen just previously tested. Test each specimen only once.

[65]

Environmental Stress Cracking Resistance (ESCR)


Scope: This procedure is used to determine the resistance of materials to cracking , when

in contact with certain reagents and under mechanical stress.

Summary: A set of specimens with controlled imperfections is immersed in a reactive

liquid maintained at specified temperature . Time required for 50% of the specimens to fail

is noted.

Principle: Polymers when exposed to certain chemicals show physical failure at

mechanical stresses that are much less than expected . ESCR quantifies resistance to such

type of failure.

Apparatus:

1. A jig for making a controlled imperfection in specimen of the dimensions,parallel to

long edges of specimen and centered on one of the broad faces.

2. Specimen Holders

3. Test Tubes

4. Corks wrapped withaluminium foil.

5. Constant temperature bath maintained at 50±0.5⁰C6. Bending clamp and transfer tool.

7. Thermometer.

[66]

Sample: Ten samples of following dimensions shall be cut from an Injection Molded or

Compression Molded sheet; 38±2.5mm×13±0.08mm×3.15±0.15mm

Procedure:

Give each specimen a controlled imperfection (notch) of 0.575±0.075mm depth on

one surface after conditioning the test samples for 24 hours at 23⁰C before testing.

Bend the specimen using bending tool.Make sure that the notch is on the outer side.

Transfer them to the specimen holder.

Insert holder in the test tube. Fill the tube with fresh reagent. Stopper the tube with

foil wrapped cork and immediately place it in the constant temperature bath.

Temperature of water bath checked and set to 50⁰C with thermometer before

starting the test.

Note the time required for 50% of the samples fail.

Specular Gloss of Plastic Products


Scope: This procedure is used to measure the specular gloss of plastics

[67]

Summary: The gloss meter is placed on the sample and the program for gloss

measurement is run.

Principle: Gloss value is determined from the ratio of incident light reflected from the

surface of the sample.

Apparatus: 3 Angle Hunter labsProgloss

Sample:PE , PP & PVC

Procedure:

1. The mode switch is first set for set up mode to prepare instrument for operation.

Select all three angles for measurements (20⁰,60⁰&85⁰).2. Place the film samples on a vacuum activated surface with a perfectly white

background.

3. Then place the instrument on the sample.

4. Press the red key.

5. The gloss values are displayed on the instrument.

Indentation Hardness of Plastics

Reference:ASTM D 2240

[68]

Scope: This procedure is used to determine the Indentation Hardness of plastic

materials.

Summary:Needle tip of specified dimensions and geometry is made to penetrate into

the polymer and the depth of penetration gives the level of the hardness of the material.

Principle:Resistance to Indentation of the material is found with the help of a hard

needle tip.

Apparatus:Shore D Hardness tester – Blue steel make.

Sample:The specimen shall be at least 6 mm thick. Two or more samples of lesser

thickness can be plied up to achieve the desired thickness.

Procedure:

1. Place the specimen on hard, even and horizontal surface.

2. Hold the tester vertically on the specimen. While holding, the pressure foot should

be parallel to the surface of the specimen.

3. Apply the pressure with hand without shock so that the casing is fully pressed

against the specimen.

4. The readings are to be taken after about 3seconds after the contact between the

surface of the specimen and the pressure foot is made.

5. Three tests should be carried out on each specimen and the mean value of these 3

readings should be rounded off to a shore number.

[69]

6. PROCESSING DIVISION

Various Processing Facilities at PARC

MOLDING

Injection Molding Machines

Blow Molding Machine

Compression Molding Machine

Rotational Molding Machine

EXTRUSION

Blown Film Extrusion Plant

Tubular Quenched PP Plant

PVC Pipe Extrusion Plant

COMPOUNDING

Single screw compounding extruder

Twin screw compounding extruder

Tumbler Mixer

High speed mixer

Granulator

Pulverizing Unit

[70]

Brief Description of Processing Machines:

1.InjectionMolding

Principle:

In the process the material is plasticized and melted by the heat added through

barrel heaters and friction due to shearing.

Then the material is injected through nozzle into a relatively cold mold to get the

desired shape.

After the shape is formed, the ejector pins push the specimen out of the mold.

The process is used to make solid articles like caps, plugs, bobbins, furniture&

house ware products, industrial & automobile parts etc.

[71]

Machines available:

Klockner Windsor FR 110

Klockner Windsor SP 180 (Family mold machine)

Arburg 320C All-rounder (ASTM standards)

Parts of a molded specimen:

[72]

Injection molding machine detailed specification

Specifications Units DGP Klockner Arburg

Windsor Windsor All rounder

SP180 FR110 320 C 500-100

Screw diameter mm 50 45 30

Injection pressure Bar 1800 1900 1550

L/D - 18:1 19:1 20:1

Clamping force KN 1800 1100 500

Min mold height mm 350 250 200

Max mold height mm 900 700 200

The theory of injection molding can be reduced to four simple individual steps:

Plasticizing, Injection, Cooling, and Ejection. Each of those steps is distinct from theothers and correct control of each is essential to success of the total process.

The steps are as follows:

Plasticizing - describes the conversion of the polymer material from its normal hard granular form at room temperatures, to the melt necessary for injection at its correct melt temperature.

Injection - is the stage during which this melt is introduced into a mold to completely fill a cavity or cavities.

Cooling - is the action of removing heat from the melt to convert it from melt back to its original rigid state. As the material cools, it also shrinks.

Ejection - is the removal of the cooled, molded part from the mold cavity and from any cores or inserts.

[73]

Advantages of Injection Molding High Production rates

Design flexibility

Repeatability within tolerances

Can process a wide range of materials

Relatively low labor

Very good finishing of parts

Minimum scrap losses

Limitations of Injection Molding

High initial equipment investment

High start-up and running costs possible

Part must be designed for effective molding Accurate cost prediction for molding job is difficult

Application: PARC uses injection molding machine for manufacturing of spiral flow

testsample, tensile testing sample, flexural testing sample, Izod testing sample, disc shape

sample and color testing sample

[74]

2.Blown Film Plant

Blown film extrusion process and salient features:

The majority of polymer films are manufactured by film blowing.Plastic melt is

extruded through an annular slit die, usually vertically, to form a thin walled tube.

Air is introduced via a hole in the centre of the die to blow up the tube like a

balloon. Mounted on top of the die, a high-speed air ring blows onto the hot film to

cool it. The tube of film then continues upwards, continually cooling, until it passes

through nip rolls where the tube is flattened to create what is known as a ' lay-flat'

tube of film. This lay-flat or collapsed tube is then taken back down the extrusion '

tower' via more rollers. On higher output lines, the air inside the bubble is also

exchanged. This is known as IBS (Internal Bubble Cooling).

The lay-flat film is then either kept as such or the edges of the lay-flat are slit off to

produce two flat film sheets and wound up onto reels. If kept as lay-flat, the tube of

film is made into bags by sealing across the width of film and cutting or perforating

to make each bag. This is done either in line with the blown film process or at a

later stage.

Typically, the expansion ratio between die and blown tube of film would be 1.5 to

4 times the die diameter. The drawdown between the melt wall thickness and the

cooled film thickness occurs in both radial and longitudinal directions and is easily

controlled by changing the volume of air inside the bubble and by altering the haul

off speed. This gives blown film a better balance of properties than traditional cast

or extruded film which is drawn down along the extrusion direction only

Tubular films show excellent toughness as they are a mild form of biaxial

orientation. Tubular lines produce products which can be easily made in to bags,

edge-trimming can be frequently avoided and a film width is easily changed simply

by blowing a bigger tube.

[75]

Machine Specifications:

LDPE/LLDPE plant HM/HDPE plant

Make Rajoo Engineers Limited Rajoo Engineers Limited

Model No RELL-4040 LAB REHD-4040 LAB

Screw diameter 40mm 40mm

Screw length 1200mm 1200mm

L/D ratio 30:1 30:1

Screw speed range 10-100rpm 10-100rpm

Die diameter 110mm spiral type 75mm spiral type

Die gap 1.2, 1.5,1.8mm 0.8,1.2mm

Parts of a tubular blown film plant:

Extruder

Extruder comprisesof hopper, barrel/screw and dies. Fig shows the component of a modernextruder.

[76]

Hopper:

All the extruder has an opening in the barrel at the driven end, through which the plastic

graduals enter the extruder. The hopper, a simple sheet –metal enclosure, is mounted

above the opening and holds about a hopper’s capacity material. Hopper is provided with

heating system, if the material has to be preheated before entering the extruder.

Screw:

This is the heart of the extruder. Screw conveys the molten polymer to the opening of the

die after properly homogenizing the molten polymer.

There is considerable variation in the design of the screw for various materials, the most

important variable being the depth of the channels. Despite much desire for universal

screw, it is advisable to use a different design for each material to achieve the best results.

PE screw is designed to have shallow channels, sudden compression and long metering

join.

Screw diameter: 20-250mm,CR: 2.5-3: 1,L/D: 24-33: 1

Mixing Heads

The metering section of a standard is not a good mixer. Smooth laminar flow patterns are

established in the channel, which do not mix dissimilar elements in the melt. Mixing

devices are frequently installed in screw to disrupt these flow patterns and improve melt

homogenization.

Breaker plate/screen pack:

[77]

Breaker plate with screen packs inserted is kept in the adapter, which connect the dies and

extruder barrel. This assembly has several functions.

1. Arrest the rotational flow of the melt and convert into axial flow.

2. Improves melt homogeneity by splitting and recombining the flow.

3. Improves mixing by increasing backpressure.

4. Remove any contamination and unmelt.

Screen packs are made up of series of screen of differing mesh. With the coarse screen

placed against the breaker plate to support the finer screens.

Die:

The dies used for tubular extrusion are centre-fed or side-fed. Centre fed dies are better as

all the points on the lip are equidistant from the feed-entry point. This gives uniform flow

and uniform thickness. The spider arms of the centre-fed die always divide the flow into

separate paths which must come together and weld completely before leaving the die or

else weld lines are formed, which are lines of weakness.

Die gap is also a very important parameter as too small die gap may cause increase in die

resistance and cause overheating in extruder and reduce output rate. And if the gap is too

large resistance becomes so less that weld lines may appear.

For the processing of PE, a die with spiral is used as shown in the figure. As the plastic

flows from the entry point it spirals around the mandrel section of the die. The land depth

between the spiral section and wall increases as the wall increases as the material progress

through the die, .as a result, the distribution around the die periphery made uniform in

order to control the gauge of extruded tube.

[78]

Corona treatment:

Many plastics, such as polyethylene and polypropylene, have chemically inert and nonporous surfaces with low surface tensions causing them to be non-receptive to bonding with printing inks, coatings, and adhesives. Although results are invisible to the naked eye, surface treating modifies surfaces to improve adhesion.

Corona treatment (sometimes referred to as air plasma) is a surface modification technique

that uses a low temperature corona discharge plasma to impart changes in the properties of

a surface. The corona plasma is generated by the application of high voltage to sharp

electrode tips which forms plasma at the ends of the sharp tips. A linear array of electrodes

is often used to create a curtain of corona plasma.

Parameter of blown film extrusion:

Temperature:

A lower temperature is needed for tubular film (e.g., 170oC for PE of 2.0 MFI) since the cooling capacity often limits the output as a higher temperature may mean lower output. The other possible disadvantages of higher temperature are:

Increased blocking

Reduced bubble stability

Promotion of decomposition in the die with resultant impaired appearance

Possible bubble breaks.

Blow up Ratio:

The blow-up ratio is defined as the ratio of the bubble diameter to the die diameter and is

one of the important factors to determine the final film size and properties. A high blow

ratio means that a smaller and less expensive die is needed for any given film size, but a

high blow-up ratio yields the strongest film as the increased stretching has an orientation

effect. However, high blow-up ratio also encourages bubble instability, requires more

drawdown and magnifies all the imperfections in the die, thus a compromise blow-up ratio

is needed. Bubble instability is a major problem in tubular film extrusion as it produces

wrinkles, thickness variation, and “walking” of the film along the windup roll.

[79]

The blow-up ratio is determined in advance, when a die is selected to do a given job. Die

gap also has significant effect on the film properties. Increasing die gap will increase

machine direction orientation which then results in lower machine direction tear strength,

lower machine elongation, improved transverse direction tear strength, & improved

machine direction tensile strength.

Frost-Line Height:

The area of change, where the viscous fluid is changed to solid film, is called the "frost-

line" because here the hardening film first appears "frosty" in some films. An irregularity

here indicates that something is wrong with the filmmaking process, and this may result in

poor film.

Increasing FLH will decrease machine direction orientation with slower quenching rates resulting in higher film crystallanity. Optical properties will reach an optimum & then start to decrease.

The frost line can be raised or lowered by means of extruder output, take-off speed, and

the volume of cooling air blown against the bubble. When the screw speed goes up the

distance between the die and the frost line is increased; when more cooling air is blown

against the bubble, the frost line drops. The frost line can be change by adjusting the

cooling-air volume. The frost line in the bubble can effectively be raised by means of a so-

called annealing chamber (or "chimney") placed between the die and the air ring.

[80]

Start-up & shutdown of the process:

The first minutes of the production always yield scrap material as the system much yield

equilibrium. The die bolts may have to adjust to get the uniform thickness, and the

extrusion speed and the winder speeds must be balanced to get the desired overall

thickness. The process is started quite cool in order to minimize formation of decomposed

material in the system, which could subsequently contaminate the film and cause streaks.

Once the screw is turning and plastic is running through the die, the temperatures are raise

to normal values. As the tube is being formed, air is introduced through the die in small

amounts to keep the tube slightly blown. After the threading is complete, more air is blown

in to bring the bubble to the desired size. Care must be taken to keep the die faces clear of

the molten resin as this may later be decomposed and cause die lines.

Shut down is one of the most vital steps in blown film extrusion in order to avoid damageto

the head and the die. Such decomposition can be caused by the degradation, oxidation of hot

plastic in contact with air, or by both. For all materials degradation and decomposition may

produce hardened bits of material which can break off and lodge in the die lips. Such bits form

weld lines which are not only unsightly but are also lines of weakness.

When the film line is shut down, material is kept moving as the zones cool to about 130oC

(LDPE) then the extruder is stopped and the die and head are cooled with air as fast as possible to inhibit decomposition. Polyethylene is often left in the extruder barrel as well as inside the die to prevent air from entering the system and oxidizing any bits of plastic left. Likewise, before start-up the die is not left hot any longer than absolutely necessary.

Winding:

Winding is the final operation in the film manufacturing process. In blown film, because

there are two sides of the tube, two winders are requires. Film is wound on a spiral wound

paper core which is supported by the winding shaft. This shaft is attached to the winder at

the ends. The core is secured to the shaft using either a cable lock mechanisms or lugs

which are pneumatically protruded from the shaft surface.

Two basics techniques used for winding films are: driving the winding roll from thecentre using a driven wind up shaft, or applying a driven roll directly to the surface of the winding roll of the film.

[81]

Centre winders: Centre winders have the advantage in that the tension in the film can

becontrolled as the diameter of the film increases. This is done by sensing the diameter of

the film & decreasing the tension of the film as the diameter of the film increases. Tension

is controlled by controlling the differences in speed between the nip rolls & the winding

rolls Tension can also be controlled by a pneumatically activated idler roll that applies

pressure on the film web. This roll is called the dancer since it pivots up& down as it

maintains the constant pressure in the web. With the higher force required to move the

dancer roll, more tension will be applied to the film. Decreasing the tension as the roll

diameter grows up, helps to keep the film roll form winding too tight. Tight winding will

cause the film to block & make it sensitive to shrink as it cools on the toll. If winding is

too tight, the shrinking film will become distorted & difficult to print or laminate.

Surface winders: Surface windersare easy to operate since they don’t have the

complexmethods of tension control. In case of surface winders, tension is applied to the

film by winding the film faster than the nip rolls. However, this does not allow for the finer

adjustments in tension as in a dancer-bar arrangement. Surface winders rely on the

pressure of the drive roll to control the roll hardness. Therefore, because some pressure is

required to drive the roll, they tend to wind harder rolls than centre winders. However,

because there is not the variation in tension & because there is no dancer rolls, some

processors believe that surface winders can wind flatter rolls than centre winders. It is

difficult, however, to change the direction of the wind on a surface winder compared to the

centre winder.

[82]

3.CompressionMolding Machine

Machine Specifications: Compression cylinder: 6 inch diameter

Make: Carver Inc. LMV 50H-15-C (50T)

Process: The process of compression molding may be simply described by reference

toFig. Two-piece mold provides a cavity in the shape of the desired molded article. The

mold is heated, and an appropriate amount of molding material is loaded into the lower

half of the mold. The two parts of the mold are brought together under pressure. The

compound, softened by heat, is thereby molded into a continuous mass having the shape of

the cavity. The mass then must be hardened, so that it can be removed without distortion

when the mold is opened.

Advantages

Advantages ofCompression Molding

Mold costs tend to be lower because the molds are simpler.

Low volume jobs are better suited to compression molding because start up is

usually quicker, easier and generates less scrap.

Cycle times for compression molded is more than injection molding

[83]

Disadvantages of Compression Molding

Compression molded parts usually are more labor intensive. Preforms must be

made, heated and loaded into the mold by an operator or a robot.

Across parting line dimensions can be more difficult to control.

It can be more difficult to mold metal inserts into the parts without flashing them.

Application: PARC uses compression molding for manufacturing of thermoplasticsheet (testing sample are punch from sheet)

NOTE: FOR PVC FOR FIRST 1 MIN IT IS OPERATED UNDER 0 BAR PRESSURE, FOR NEXT 1 MIN IT IS 15 BAR PRESSURE AND FOR NEXT 2 MINUTES IT IS 30 BAR PRESSURE.

FOR PE, PP FOR THE FIRST 1 MINUTES IT IS 0 BAR PRESSURE, FOR NEXT 2 MINUTES IT IS 15 BAR PRESSURE AND FOR THE NEXT 3 MINUTES IT IS 30 BAR PRESSURE.

COOLING IS DONE AT 70 °C FOR PVC AND 50°C FOR PP,PE.

[84]

4.RotationalMolding

Make: Fixotron 50K2

Rotational molding (often referred to as Rotomolding or Rotomolding) is a process used

for producing hollow plastic products. By using additional post-molding operations,

complex components can be produced enabling the process to compete effectively with

other molding and extrusion practices.

Rotational molding differs from other processing methods in that the heating, melting,

shaping, and cooling stages all occur after the polymer is placed in the mold, therefore no

external pressure is applied during forming.

Advantages of RotationalMolding

Economically produced large products

Minimum design constraints

Stress-free products

No polymer weld lines

Comparatively low mold costs

[85]

Disadvantages of Rotational Molding

The manufacturing times are long

The choice of molding materials is limited

The material costs are relatively high due to the need for special additive packages

and the fact that the material must be ground to a fine powder

Some geometrical features (such as ribs) are difficult to mold

Process:The Rotational Molding process is essentially split into four operations:

Charging Mold:A pre-determined amount of polymer powder is placed in the mold. With

the powder loaded, the mold is closed, locked and loaded into the oven. The powder can be

pre-compounded to the desired color.

Heating & Fusion:Once inside the oven, the mold is rotated around two axes, tumbling

the powder – the process is not a centrifugal one. The speed of rotation is relatively slow,

less than 20 rev/min. The ovens are heated by convection, conduction and, in some cases,

radiation. As the mold becomes hotter the powder begins to melt and stick to the inner

walls of the mold. As the powder melts, it gradually builds up an even coating over the

entire surface.

Cooling: When the melt has been consolidated to the desired level, the mold is cooled

either by air, water or a combination of both. The polymer solidifies to the desired shape.

Unloading/Demolding: When the polymer has cooled sufficiently to retain its shape and

be easily handled, the mold is opened and the product removed. At this point powder can

once again be placed in the mold and the cycle repeated.

[86]

Typical Materials Used

LDPE, LLDPE,PP,PVC

Rotation Molded Kyak

[87]

6.ExtrusionBlow Molding

Make: Klockner Windsor India Ltd, Model : KBM-5

Blow molding is a manufacturing process by which hollow plastic parts are formed.

Principle: The blow molding process begins with melting down the plastic and forming it

into a parison or in the case of injection and injection stretch blow molding (ISB) a

preform. The parison is a tube-like piece of plastic with a hole in one end through which

compressed air can pass.The parison is then clamped into a mold and air is blown into it.

The air pressure then pushes the plastic out to match the mold. Once the plastic has cooled

and hardened the mold opens up and the part is ejected.

Process: In Extrusion Blow Molding (EBM), plastic is melted and extruded into a hollow

tube (a parison). This parison is then captured by closing it into a cooled metal mold. Air is

then blown into the parison, inflating it into the shape of the hollow bottle, container, or

part. After the plastic has cooled sufficiently, the mold is opened and the part is

ejected.Continuous and Intermittent are two variations of Extrusion Blow Molding. In

Continuous Extrusion Blow Molding the parison is extruded continuously and the

individual parts are cut off by a suitable knife. In Intermittent blow molding there are two

processes: straight intermittent is similar to injection molding whereby the screw turns,

then stops and pushes the melt out. With the accumulator method, an accumulator gathers

melted plastic and when the previous mold has cooled and enough plastic has

accumulated, a rod pushes the melted plastic and forms the parison. In this case the screw

may turn continuously or intermittently.[3] with continuous extrusion the weight of the

[88]

parison drags the parison and makes calibrating the wall thickness difficult. The

accumulator head or reciprocating screw methods use hydraulic systems to push the

parison out quickly reducing the effect of the weight and allowing precise control over the

wall thickness by adjusting the die gap with a parison programming device

Advantages of extrusion blow molding

High rate of production

Low tooling cost

Disadvantages of extrusion blow molding

High scrap rate

A limited control over wall thickness

Difficulty of trimming away excess plastic.

[89]

COMPOUNDING

1. Single screw compounding extruder :

Make: Thermo Electron Corporation

Machine Specifications: Screw diameter: 19mm

L/D ratio: 25:1

Compression ratio- 3:1

Maximum screw speed: 200rpm

Overview: Single-screw laboratory extruder deliver reliable data captured during the extrusion

process to verify process parameters (speed, energy, temperature) for unknown materials or to

manufacture smaller quantities of a new polymer (as strands, sheets, pellets, blown films) during

research and development. The extruder is equipped with measuring ports for melt pressure and melts

temperature to study the process parameters along the extruder barrels. A die can be connected to the

end of the extruder barrel to form the polymer melt as strand or film. Special rheological dies allow

the determination of shear- and elongational viscosity at defined shear rates.. Standard feeders for

pellets and special feeding systems for powders, pastes, liquids are there.

Application: Single screw compounding extruder is use for checking the decrease inproperties of material after no. of passes.

2.Twin screw compounding extruder:

Type: Co-rotating twin screw extruder

Make: Omega 30 STEER

[90]

Process:In the extrusion of plastics, raw compound material in the form of nurdles (small

beads, often called resin) is gravity fed from a top mounted hopper into the barrel of the

extruder. Additives such as colorants and UV inhibitors (in either liquid or pellet form) are

often used and can be mixed into the resin prior to arriving at the hopper.

The material enters through the feed throat (an opening near the rear of the barrel) and comes

into contact with the screw. The rotating screw (normally turning at up to 120 rpm) forces

the plastic beads forward into the heated barrel. The desired extrusion temperature is rarely

equal to the set temperature of the barrel due to viscous heating and other effects. In most

processes, a heating profile is set for the barrel in which three or more independent PID-

controlled heater zones gradually increase the temperature of the barrel from the rear (where

the plastic enters) to the front. This allows the plastic beads to melt gradually as they are

pushed through the barrel and lowers the risk of overheating which may cause degradation in

the polymer.

Extra heat is contributed by the intense pressure and friction taking place inside the barrel. In

fact, if an extrusion line is running certain materials fast enough, the heaters can be shut off

and the melt temperature maintained by pressure and friction alone inside the barrel. In most

extruders, cooling fans are present to keep the temperature below a set value if too much heat

is generated. If forced air cooling proves insufficient then cast-in cooling jackets are

employed.

At the front of the barrel, the molten plastic leaves the screw and travels through a screen

pack to remove any contaminants in the melt. The screens are reinforced by a breaker plate

(a thick metal puck with many holes drilled through it) since the pressure at this point can

[91]

exceed 5,000 psi (34 MPa). The screen pack/breaker plate assembly also serves to create

back pressure in the barrel. Back pressure is required for uniform melting and proper mixing

of the polymer, and how much pressure is generated can be "tweaked" by varying screen

pack composition (the number of screens, their wire weave size, and other parameters). This

breaker plate and screen pack combination also does the function of converting "rotational

memory" of the molten plastic into "longitudinal memory".

After passing through the breaker plate molten plastic enters the die. The die is what gives

the final product its profile and must be designed so that the molten plastic evenly flows from

a cylindrical profile, to the product's profile shape. Uneven flow at this stage can produce a

product with unwanted residual stresses at certain points in the profile which can cause

warping upon cooling. Almost any shape imaginable can be created so long as it is a

continuous profile.

The product must now be cooled and this is usually achieved by pulling the extrudate

through a water bath.

Machine Specifications: Screw diameter: 30mm

L/D ratio- 40:1

Screw speed range: 0-1200 rpm

Throughput : 50-100 kg/hour

Application :Twin screw extruder is use mainly for PP compounding and PVC

3.Pulverizing Unit:

The pulveriser unit is capable of pulverizing polymer granules 500μm to 1.75mm.

Make: Fixopan Machines Pvt Ltd.

Model no: FP14-SGL

Capacity: 40-60 kg per hour

Grinding teeth: Multiple (Over 250)

[92]

4.Tumbler Mixer:

Capacity –40kg of pellets

Application : It is use for the physical mixing of granules

5.High Speed Mixer:

Make: KOLSITE

Specifications:

Capacity: 40kg

Speed: 1440rpm

Application :Used for PVC compounding.

6. Granulator:

Make: PIMCO

Specifications: 5hp, 3.7kW induction motor.

Application: Use for making granules

[93]

References

ASTM Standards Handbook volume 08.01, 08.02, 08.03 , 08.04

Polymer Science and Technology- V. Gowarikar

http://ulprospector.com

BRYDSON, J. A. (1999) Plastics Materials (7th edition)

http://ulprospector.com/

Report on PARC

Documents

Transcript of Report on PARC