sign in sign up
<<
Home , Food packaging, Polyethylene

ILSI Rep for pdf 8/04/03 9:39 Page a

ILSI Europe Report Series

PACKAGING M ATERIALS 4. P OLYETHYLENE FOR F OOD PACKAGING A PPLICATIONS

REPORT

Prepared under the responsability of the ILSI Europe Packaging Material Task Force ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page b

About ILSI / ILSI Europe

The International Life Sciences Institute (ILSI) is a nonprofit, worldwide foundation established in 1978 to advance the understanding of scientific issues relating to , safety, toxicology, risk assessment, and the environment. By bringing together scientists from academia, government, industry, and the public sector, ILSI seeks a balanced approach to solving problems of common concern for the well-being of the general public. ILSI is headquartered in Washington, DC, USA. Branches include Argentina, Brazil, Europe, India, Japan, Korea, Mexico, North Africa and Gulf Region, North America, North Andean, South Africa, South Andean, Southeast Asia Region, the focal point in China, and the ILSI Health and Environmental Sciences Institute (HESI). ILSI is affiliated with the World Health Organization as a non-governmental organisation (NGO) and has specialised consultative status with the Food and Agriculture Organization of the United Nations.

ILSI Europe was established in 1986 to identify and evaluate scientific issues related to the above topics through symposia, workshops, expert groups, and resulting publications. The aim is to advance the understanding and resolution of scientific issues in these areas. ILSI Europe is funded primarily by its industry members.

This publication is made possible by support of the ILSI Europe Packaging Material Task Force, which is under the umbrella of the Board of Directors of ILSI Europe. ILSI policy mandates that the ILSI and ILSI branch Boards of Directors must be composed of at least 50% public sector scientists; the remaining directors represent ILSI’s member companies. Listed hereunder are the ILSI Europe Board of Directors and the ILSI Europe Packaging Material Task Force members.

ILSI Europe Board of Directors members

Prof. N.-G. Asp, Swedish Nutrition Foundation (S) Prof. P.A. Biacs, Bay Zoltán Foundation for Applied Research (H) Prof. J.W. Bridges, University of Surrey (UK) Prof. G. Eisenbrand, University of Kaiserslautern (D) Prof. M.J. Gibney, University of Dublin (IRL) Prof. A. Grynberg, National Institute for Agricultural Research (F) Dr. M.E. Knowles, Coca-Cola (B) Dr. I. Knudsen, Danish Veterinary and Food Administration (DK) Prof. R. Kroes, IRAS – Utrecht University (NL) Dr. G. Malgarini, Ferrero Group (B) Mr. J.W. Mason, Frito Lay Europe (UK) Dr. D.J.G. Müller, Procter & Gamble European Service GmbH (D) Dr. J. O’Brien, Danone Vitapole (F) Prof. L. Serra Majem, University of Las Palmas de Gran Canaria (E) Drs. P.J. Sträter, Südzucker AG Mannheim/Ochsenfurt (D) Prof. V. Tutelyan, National Nutrition Institute (RUS) Prof. P. van Bladeren, Nestlé Research Center (CH) Prof. W.M.J. van Gelder, Royal Numico (NL) Drs. P.M. Verschuren, Unilever Health Institute (NL) Dr. J. Wills, Masterfoods (UK)

ILSI Europe Packaging Material Task Force member companies

Coca-Cola (B ) Cognis Deutschland GmbH (D) Danone Vitapole (F) Dow Europe S.A. (CH) Frito Lay Europe (UK) Nestec Ltd. (CH) Numico Research (NL) SQTS – Swiss Testing Services (CH) Valspar Corporation (UK) ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 1

PACKAGING MATERIALS 4. POLYETHYLENE FOR APPLICATIONS

By Philip Tice

REPORT PREPARED UNDER THE RESPONSIBILITY OF THE ILSI EUROPE PACKAGING MATERIAL TASK FORCE

April 2003 ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 2

© 2003 International Life Sciences Institute

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright holder. The International Life Sciences Institute (ILSI) does not claim copyright on U.S. government information.

Authorization to photocopy items for internal or personal use is granted by ILSI for libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Services, provided that $0.50 per page per copy is paid directly to CCC, 222 Rosewood Drive, Danvers, MA 01923. Phone: (+1) 978 750 8400, Fax: (+1) 978 750 4470.

ILSI®, “A Global Partnership for a Safer, Healthier World.®”, and the International Life Sciences Institute (ILSI) logo image of the microscope over the globe are registered trademarks of the International Life Sciences Institute. The use of trade names and commercial sources in this document is for purposes of identification only and does not imply endorsement by ILSI. In addition, the views expressed herein are those of the individual authors and/or their organizations, and do not necessarily reflect those of ILSI.

For more information about ILSI / ILSI Europe, please contact

ILSI Press One Thomas Circle, NW Ninth Floor Washington DC 20005-5802 USA Phone: (+1) 202 659 0074 Fax: (+1) 202 659 3859 E-mail: [email protected] Website: http://www.ilsi.org

ILSI Europe Avenue E. Mounier 83, 6 B-1200 Brussels Belgium Phone: (+32) 2 771 00 14 Fax: (+32) 2 762 00 44 E-mail: [email protected] Website: http://europe.ilsi.org

Printed in Belgium

ISBN 1-57881-155-4 ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 3 P CONTENTS MATERIALS ACKAGING

INTRODUCTION 4

WHAT IS POLYETHYLENE? 5 : 4. BASIC CHEMISTRY 8 OYTYEEFRFO AKGN APPLICATIONS PACKAGING FOOD FOR POLYETHYLENE POLYETHYLENE AND FOOD PACKAGING APPLICATIONS 11

REGULATORY 13

SAFETY/TOXICOLOGY 16

ENVIRONMENTAL ASPECTS 18

GENERAL CONCLUSIONS 20

REFERENCES 21

Author: Philip Tice (UK) Scientific Reviewer: Vince Marron (NL) Report Series Editor: Kevin Yates (UK)

3 ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 4

INTRODUCTION

olyethylene, often called polythene, is probably the most well known to the consumer and is used in greater volume worldwide than any other P plastic. The total global production of rose from 158 million tonnes to 180 million tonnes per annum between 1998 and 2000 – an increase of 12%. In Western Europe in 2000, polyethylene plastics represented 39% of standard plastics consumed, and totalled 11.7 million tonnes. Future annual demand growth for polyethylene plastics in Western Europe is predicted to be about 6%, with the major application continuing to be packaging. Typically over 50% of packaging plastics are consumed in the food and food services sectors (Zaby, 2001; Anonymous, 2001). Polyethylene’s dominance as a food packaging plastic is due to its relatively low cost, its range of versatile properties, and the ease with which it can be processed into the various packaging forms. Although polyethylene plastics were first produced over 50 years ago, manufacturing and processing developments continue to improve its properties, performance, and food packaging applications. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS : 4. ACKAGING MATERIALS P

4 ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 5 P WHAT IS POLYETHYLENE? MATERIALS ACKAGING

olyethylene, a , is the principal member of the class of . It was discovered by accident in 1933 when scientists working in the P ICI laboratories in the UK found that when was subjected to high pressure a wax-like polymeric substance was formed. This discovery led in the late 1930s to free-

processes operating at high pressures and high to produce branched : 4.

ethylene polymers – now known as Low- PolyEthylene (LDPE). These developments APPLICATIONS PACKAGING FOOD FOR POLYETHYLENE became significant in the early 1940s, when the polymers found immediate use as highly efficient electrical insulating materials and played an important role in establishing reliable and practical airborne systems (Mark et al., 1985).

The polyethylene plastics produced today are based on a family of polymers derived from ethylene and various α-olefin co-, including 1-propene (propylene), 1-butene, 1-, and 1-. They are the most widely used plastics for commodity packaging. Other polyethylene co-polymers are manufactured with co-monomers such as , producing the ethylene vinyl acetates, and various acrylics, producing, for example, the co-polymers known as the . The range of ethylene co-polymers produced with the non- monomers will not be covered in this report. Co-polymers with 1-propene (propylene) are included in the ILSI Europe report as a Packaging Material for and Beverages.

The original polyethylene (LDPE) has been supplemented with two other widely-used types – High-Density PolyEthylene (HDPE) and Linear Low-Density PolyEthylene (LLDPE). Other classifications are sometimes used for particular specialised polyethylene polymers; they include very-low-density polyethylene (VLDPE), medium-density polyethylene (MDPE) – which is often considered to be at the high-density end of LDPE polymers – ultra-high-molecular-weight polyethylene (UHMWPE), and cross-linked polyethylene.

As the names of the polyethylene types suggest, the principal physical property marking the differences between them is the density. The differences in density are basically due to differences in the degree of , which also influences the plastics’ ranges. Typical values for these parameters are listed in the following table (Brady et al., 1997; Ashford, 1994):

PE Density, g/cm3 Degree of Melting point Molecular crystallinity, % range,°C weight, Daltons

LDPE 0.915–0.940 45–55 105–115 10,000–50,000

LLDPE 0.915–0.926 30–45 112–124 50,000–200,000

HDPE 0.940–0.970 70–90 120–130 up to 250,000

5 ILSI RepPolyethyleneforpdf8/04/039:39Page6

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS polyethylene plasticstherefore containeffective (seeSectiononBasicChemistry). branches andcross-linking (GächterandMüller, 1993).Theformulationsofallcommercial used forprocessing. With thepolyethylenes,oxidationresults intheformationoflong-chain All olefinpolymersare prone tooxidativedegradation,particularlyattheelevatedtemperatures Polyethylene physicalproperties inrelation topolymerdensity indicated (Rubin,1990). physical properties. Theserelationships are notlinear, butthechangesfollowdirections The followingdiagramillustratestherelationships betweenpolymerdensityandtheprincipal and are more opaque(Parker, 1997). LDPE filmstendtobesoftandrelatively clear, whereas filmsmadefrom HDPEhaveacrispfeel density/crystallinity allowsthepolyethylenetypetobeidentifiedfairlyeasily. Forexample, with decreasing density/crystallinity. Therelationship betweenthesephysicalproperties andthe transition temperatures, whichare intherangeof–80°Cto–120°C.Claritygenerallyimproves ’ highdegree oftoughnessatlowtemperatures isduetotheverylowglass density/crystallinity. Toughness andtensilestrength alsoincrease withmolecularweight.The Yield strength andstiffness togetherwiththermalandothermechanicalproperties increase with weight, andmolecularweightdistribution. and stiffness, varywiththebasicpolyethyleneparametersofdensity/crystallinity, molecular organic substancesare onlymoderate.Thesecharacteristics,alongwithproperties suchasclarity which packagingcanbeheat-sealed.Thebarrierproperties ofpolyethyleneplasticstooxygenand polyethylene plastics,whichisduetotheirrelatively lowmeltingpointranges,istheeasewith particularlyimportantproperty of strength, andgoodbarrierproperties tomoisture. A Polyethylene plasticshavethegenerallyadvantageousproperties oftoughness,hightensile Property Polymer Physical High Low Low Clarity, tearstrength, elongation Tensile strength andfitness and gastransmission Polymer Density 6 High PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 7 1985). et al. HDPE has also been claimed to be an accidental discovery at Phillips in the early 1950s. in the Petroleum discovery at Phillips to be an accidental also been claimed HDPE has a crystallinity and of high degree polymer with that a polyethylene found Phillips researchers MPa, and 3 to 4 from ranging low pressures, more under produced high density was relatively oxide supported containing 70°C to 100°C, with catalysts ranging from temperatures polymers with similar polyethylene catalyst). In 1953 Ziegler produced on silica (Phillips halides and alkylaluminium with a catalyst system based on crystallinity and density and of atmospheric pressure catalysts), and with even milder conditions compounds (Ziegler with both the Phillips and the produced 50°C to 100°C. The polymers ranging from temperatures ethyl. They were with only short side chains, mainly linear, substantially Ziegler catalysts were The HDPE polymers (HDPE) range of polymers. of the high-density the forerunners also substantially linear polymers. today are manufactured polymers, as the name also substantially linear polyethylenes (LLDPE) are The linear low-density length of which depends on the co- used in the implies, but they have side chains, the is common co-monomers being 1-butene, 1-hexene, and 1-octene. The density – the manufacture 2.5 to 3.5 mole % ranges from which typically amount and type of co-monomer, by the controlled Mark 1998; (Kroschwitz, ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 7 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI RepPolyethyleneforpdf8/04/039:39Page8

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS are colourlessliquids(Ashford, 1994). At ambienttemperature andpressure, ethyleneand1-buteneare .Theothertwomonomers are the of monomer ethylene(ethene).Theco-monomersincorporatedtomodifythepolymers’properties manufacture the in The principalchemicalsubstanceusedtomanufacture therangeofpolyethylenepolymersis used co-monomers and Monomers BASIC CHEMISTRY Commercial manufacture of polyethylene plastics own, whichproduces thehomopolymer, orwiththeabove-mentioned polyethylene of The variouspolyethylenepolymertypesare manufactured bypolymerisingethyleneeitheronits manufacture Commercial polyethylene plastics. feedstocks. About halfofallethyleneproduced isusedinthemanufacture of Ethylene andthe 1-butene CH reactor processes byco-polymerisingethylenewithoneormore ofthe Linear low-densitypolyethylene(LLDPE)isusuallymanufactured ineithergasphaseorslurry 1997; Kroschwitz, 1998). agents. Molecularweightsare typicallyintherange 10,000to50,000Daltons(BradyandMarsh, are controlled bythepressure usedintheprocess andbytheconcentrationofchaintransfer important polymercharacteristics,suchasmolecularweightanddistribution, reaction used–thelowerreaction temperature, thehigher the density. Other processes are inuse.Thedensity/crystallinityoftheresulting polymerisdeterminedbythe small amountofoxygenoranorganic . Bothstirred autoclaveandtubularreactor ranging from 100to135MPa,attemperatures intherangeof150°Cto300°C,presence ofa Low-density polyethylene(LDPE)ismanufactured from ethylenemonomerusinghighpressures produces theolefinco-polymers. polymer produced. Molecularweightsrangefrom 50,000to200,000Daltons. type ofco-monomer–1-butene,1-hexene,or1-octenealsoinfluencesothercharacteristicsthe monomer used,typically2.5to3.5mole%,withhigheramountsresulting inlowerdensities.The of acatalyst,suchastheZieglertype.Thedensityisdeterminedlargely bytheamountofco- low pressure conditions,typically2to7.5MPa,andwithtemperatures upto250°Cinthepresence polyethylene plastics polyethylene α -olefins: 1-butene,1-hexene,and1-octene. .t–° .t6° b.pt121°C b.pt63°C b.pt –6°C 2 =CHCH α -olefin monomersare obtainedatlowcostbycrackingpetroleum andother 2 CH 3 1-hexene CH ethylene CH 2 2 =CH(CH =CH 2 8 b.pt –104°C 2 ) 3 CH 3 1-octene CH α α -olefin monomers,which -olefin monomersunder 2 =CH(CH 2 ) 5 CH 3 PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 9 ). It is also necessary to ensure that the additives are of a good that the additives are ). It is also necessary to ensure see Section on Regulatory ., 2000). Additives used in polyethylene basic polyethylene polymers and the co-polymers in order Additives must be incorporated into the plastics and processing the efficient and to ensure physical properties the desired to maintain and provide plastics must be All additives used in food contact polyethylene handling of the finished products. and comply with any migration or other safety regulations in the relevant for use approved ( restrictions to packaged foodstuffs. or off-odours quality and that they do not impart taints the to oxidation at is Polyethylene, polyethylene is prone As noted above in the section on What packing types, typically into the various forms and used during processing elevated temperatures oxidative the necessary to prevent therefore Antioxidants are in the range of 180°C to 280°C. used – the phenolic and phosphite types are main Two degradation of the polymer. % wt. The phenolic antioxidants also act as stabilisers types – at concentrations of 0.01 to 0.5 1993). (Gächter and Müller, of slip () and blocking (film layers sticking together) For films, the particular properties into the and processing handling during manufacture and efficient must be enhanced for effective is achieved by the addition of slip agents properties finished packaging. Enhancement of these the fatty acid amides – slip agents are Typical and suitable fine particulate fillers to the polymer. (Gächter the film surface after manufacture to – which “bloom” (diffuse) oleamide and erucamide 1993). and Müller, white plastics. The typically used to produce are dioxide and calcium carbonate Titanium stiffness, of , the properties inclusion of calcium carbonate in the polymer also improves Shrinkage and elongation and printability as well as permeability to and to vapour. 1993). (Gächter and Müller, reduced are on the charges Polyethylene plastics, like most plastics, have a tendency to accumulate static and “pick-up” of dirt on the finished packaging, in handling problems surface. This can result Antistatic agents are the external appearance of the film, , or . which affects antistatic agents used with polyethylene plastics Typical incorporated to minimise this problem. monostearate, and the ethoxylated secondary amines, include polyethylene glycol , glycerol have hydrophilic added to the polymer at concentrations of 0.1 to 0.5% wt. These agents in their migration to the plastic’s which results and limited solubility in the polymer, properties they become active. They can also be applied externally to films and as surface, where 1993). aqueous or alcoholic solutions (Gächter and Müller, High-density polyethylene (HDPE) is manufactured as the homopolymer using reaction as the homopolymer (HDPE) is manufactured polyethylene High-density for to those used conditions similar and temperature and pressure catalyst systems, processes, polymers be used to produce of co-monomer can Small amounts polyethylene. linear low-density used determines the molecular weight the density range. The type of catalyst at the lower end of included. of by the proportion is controlled molecular weight distribution, whereas 1992). Daltons (Brown, as high as 250,000 are Molecular weights which produce with the catalysts, polymers can be manufactured LLDPE and HDPE and in co-monomer both in molecular weight distribution structures polymers with uniform of enhanced properties, these polymers have a number films made from incorporation. LLDPE Hernandez 2001; and clarity (Kulshreshtha, resistance, toughness, puncture including improved et al ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 9 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI RepPolyethyleneforpdf8/04/039:39Page10

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS variety ofexposure conditions(Lickly on migrationofantioxidantsfrom polyethylene plasticswithstandard foodsimulantsundera migration havebeencomprehensively reviewed (Figge,1996).Otherstudieshavereported data container, etc.Data onmigrationofadditivesfrom polyethyleneandthefactorsinfluencing manufacture tendtobelostduringthesubsequent processing intothefinishedpackagingfilm, monomers usedinthemanufacture ofpolyethylene plastics,anyresidues remaining after and additives(CzerniawskiPogorzelska,1997).With therelatively highvolatilityofallthe overall migrationlimitof10mg/dm containers—and withallfourstandard foodsimulants are typicallywellbelowtheregulatory Reported migrationvaluesforpolyethyleneplasticsinallforms—films,pots,tubs,andother in safetylawsandregulations. Any migrationofsubstancesfrom polyethyleneplasticsmustcomplywithrestrictions specified and beverages. ranges, buttheyare usedaspackagingforawiderangeofwater-based andfat-containingfoods there ishigh-temperature contactwithfoodstuffs becauseoftheirrelatively lowmeltingpoint into high-moisture foods.Polyethyleneplasticsare notgenerallyusedinapplicationswhich fatty foods,whereas hydrophilic substances,suchasanti-staticagents,haveatendencytomigrate Hydrophobic substances,suchasoligomersandtheantioxidants,haveatendencytomigrateinto of polyethyleneplasticsincontactwithfoodare describedbelow, inthenextsection. foods. With allplastictypes,migrationincreases withtemperature andtimeofcontact.Theuses Migration intoliquidfoodswillbehigherthanthatmore solidfoodstuffs, particularlydry largely onthetypeoffoodorbeverage,temperature duringcontact,andthecontacttime. polyethylene plasticsintothefoodsandbeverageswithwhichtheycomecontactdepend use formulations orthemanufacturingprocess. Thequantitiesofsubstancesthatmigratefrom of low-molecular-weight polymers(oligomers),andanyadditivesorothersubstancesusedinthe conditions under Substances thatmaymigratefrom polyethyleneplasticstofoodstuffs includeresidual monomers, polyethylene from Migration dispersed inthesameorsimilarpolymertypes. containers, etc.)bymeansofmasterbatches.Masterbatchesare concentratesoftheadditive(s) conveniently incorporatedintothebasicpolymerbefore processing intothefinalproduct (films, Additives suchascolourants,whiteningagents,slipadditives,andantistaticagentsare often 1993). and are particularlyeffective atthelowconcentrationsof0.05to0.15%wt(GächterandMüller, injection mouldingoperations.Sodiumalkanesulphonates(C16–C18)are alsousedaslubricants Some antistaticagentscanactinadditionasexternallubricantsduringfilmmanufacture and 2 and anyrelevant specificmigrationlimitsforthe monomers et al ., 1990;Goydan,1990). 10 PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 11 , 2000) and are then converted into and pouches. They then , 2000) and are et al. olyethylene, the first commodity plastic to be used for food packaging, came into commodity plastic to be used for food olyethylene, the first position as a Since then it has achieved its dominant general use in the 1950s. of its relatively a wide range of foods and beverages because packaging material for P Polyethylene-coated foil is extensively used as lidding material for pots and other Polyethylene-coated is extensively used as lidding material to the sub- containers. The polyethylene that melts under heat and bonds the aluminium the sealability of these foils. provides structure In special multi-layer packaging materials, polyethylene is combined with and paperboard In special multi-layer packaging materials, polyethylene is combined with A coating. aluminium by juices typical example is the container for packaging long-life fruit a barrier to provides and milk. The polyethylene allows the container to be easily heat sealed and also which ensures and the aluminium acts as an oxygen barrier, rigidity, provides The paperboard water. maintained during its . For foodstuffs are that the safety and quality of the packaged product coated on both Paperboard aluminium layer. does not contain an with a short shelf life, the structure take-away products, surfaces with polyethylene is extensively used for boxed containers for milk is and fatty foods, and for disposable beverage cups. Polyethylene-coated paperboard high-moisture to ambient). range (frozen widely used as external for many foods, over a wide temperature by spot contact heating. easily heat sealed in food packaging line processes Such cartons are The two main end forms of polyethylene plastics used for food packaging are: of polyethylene plastics used for The two main end forms • by both cast and oriented processes films, made • processes. and other containers made by and blow moulding for these two used are physical properties types of polyethylene with the appropriate Different for the principal types used – LDPE and LLDPE – are applications. The low-density polyethylenes rigid HDPE is the main polymer used for containers. films, and the more for LDPE polymers, the newer LLDPE reserved In some of the film applications originally elongation to break of their superior tensile strength, polymers have taken over because of the two properties The water vapour transmission resistance. characteristics, and puncture enhanced films require 1998). In applications in which similar (Kroschwitz, polymer types are used. HDPE polymers are rigidity, making them bi-axially oriented by means of the “bubble” process stretching Most films undergo at the molecular level (Hernandez POLYETHYLENE AND FOOD PACKAGING AND FOOD POLYETHYLENE APPLICATIONS are often laminated with other plastic types for applications in which the polyethylene is used for with other plastic types for applications in which the polyethylene is used often laminated are A water vapour. heat sealing and/or as a barrier to is typical laminate combination the necessary the nylon provides foods. Here () with polyethylene for boil-in-the- of boiling water. rigidity at the temperature combined with a variety of polymer types, such as In other laminates polyethylene is (PP), , (PVdC) and (PET), polypropylene polyethylene terephthalate and properties the particular required ethylene (EVOH), selected to provide an aluminium required, to oxygen are performance characteristics. When good barrier properties also acts the structure where foil layer is incorporated. Such flexible packaging is used for coffee, retained. are aromas ensuring that the coffee as a barrier in reverse, low cost, its versatile properties, and the ease with which it can be manufactured and converted. the ease with which it can be manufactured and properties, low cost, its versatile ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 11 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 12

Aluminium is also used decoratively on polyethylene films in the form of very thin produced by the vacuum deposition process. These aluminium-coated films are commonly used in the UK for packaging bread.

For food products with a short shelf life, such as fresh fruit and vegetables, polyethylene film bags provide simple but effective packaging. Meat and fish products with a short shelf life are often packaged on plastic trays, such as foamed , and overwrapped with polyethylene film. The low transition temperatures (Tg) of low-density polyethylene means that the films remain flexible at low temperatures. This characteristic makes them the preferred films for packaging products.

For many years in the UK and elsewhere, milk bottles were made of glass, which could be easily cleaned and sterilised for reuse, and milk was delivered to the home. As shopping habits changed and milk was more frequently purchased at food , glass became less suitable as a material for milk bottles and was largely replaced by HDPE. Bottles for milk, fruit juices, soups, and a variety of other liquid beverages constitute the single largest use for HDPE plastics in the UK. Elsewhere in Europe, polyethylene-coated board constructions are more common for these

POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS foodstuffs. When HDPE bottles were first introduced in the UK, they were intended to be single-use and disposable. Collection and schemes for the plastic bottles are now in operation as part : 4. of the efforts for national compliance with the current environmental legislation. Developments in the design of HDPE bottles include multi-layer structures with oxygen barrier , such as ethylene vinyl alcohol (EVOH), which allows foodstuffs to have an extended shelf life.

Both HDPE and LDPE plastics are used to produce a wide variety of caps and covers for bottles and containers. The use as films for container is also growing.

ACKAGING MATERIALS Many of the polyethylene films and containers used to package food and beverages are printed P to provide product identification, information on use, and decoration. Because polyethylene plastics have low surface energies, surface treatments are necessary to enable inks to achieve adequate . Corona discharge, flame, and ozone treatments are commonly used to increase the by imparting a degree of oxidation to the polyethylene surface (Hernandez, et al., 2000).

Some examples of foods and beverages for which polyethylene-based packaging is used are listed below:

• fresh fruit and vegetables – film bags, heat-sealed overwrapping film, and container liners for bulk transport • frozen fruit, vegetables, meat, poultry, and fish products – film bags and heat-sealed overwrapping films • cereals – film bags, sometimes with carton board outer packaging • bread and bakery products – film bags • milk, milk-based drinks, soups, fruit juices, and fruit drinks – HDPE bottles and polyethylene/cartonboard/polyethylene laminate containers • long-life fruit juices and milk – polyethylene/aluminium/cartonboard/polyethylene laminate containers • yoghurt and other products – polyethylene/aluminium lidding • take-away foods and beverages – polyethylene/paperboard/polyethylene laminate containers • coffee – polyethylene/aluminium/polyethylene terephthalate laminate bags.

12 PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 13 Commission Directives on plastics used for packaging of foodstuffs As part of the process of harmonising legislation within the European Union Member States, the Union Member States, legislation within the European of harmonising As part of the process with the safety of all concerned Directives framework Commission (EC) has introduced European has started work on and foodstuffs, intended to come into contact with materials and articles is 89/109/EEC, which lays Directive framework The current for specific material types. Directives as avoidance of any danger to human In short, these may be stated down the general principles. foodstuff. of the quality of the packaged health and the maintenance (90/128/EEC) to deal with plastics has been under continuous The first major specific Directive to establish the limits of acceptance for all plastic development since its inception. It seeks and additives) in foodstuffs. components (e.g. monomer residues contains an overall migration limit and a list of authorised plastic 90/128/EEC Directive either in terms of specific migration limits (SML) or maximum monomers, some with restrictions, to substances in the material or article (QM). The amendments permitted quantity of the residual but most significantly they the list of monomers, have added to or altered 90/128/EEC Directive As with the plastic classified as incomplete. a list of additives, which is currently have introduced assigned specific migration limits. monomers, some additives have been of had been amended six times, it was decided in 2002, for reasons 90/128/EEC After Directive August 2002 as This was published in Directive. a consolidated to produce clarity and rationality, will be made as the Amendments to the consolidated Directive 2002/72/EC. EC Directive further developed. are regulations Union Member into use by individual European brought are the EC Directives of The provisions laws and legislative systems. States by implementing them in their national Union being adopted by non-European increasingly are food contact regulations The European Member States and other countries outside Europe. to and articles as well as other related Full details on all of the Directives Commission DG SANCO website on Food documents can be found at the European related and Contact Materials: http://europa.eu.int/comm/food/fs/sfp/food_contact/index_en.html, on behalf of the EC by which is organised at the website http://cpf.jrc.it/webpack/legislat.htm, of the Institute of Health and Consumer and Consumer Goods Group the Food Products in Ispra, Italy. Centre at the Joint Research Protection REGULATORY European regulations that apply to polyethylene: Specific European ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 13 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 14

Migration: overall migration limits, specific migration limits

The overall migration limit contained in Directive 2002/72/EC is specified as 10 milligrams of plastics substances released per square decimetre of plastic surface area (mg/dm2) or, alternatively, 60 milligrams of plastics substances transferring to 1 kilogram of foodstuff (mg/kg).

Ethylene, the principal monomer used to manufacture polyethylene, and the three monomers 1-butene, 1-hexene, and 1-octene used as co-monomers, are in the List of Authorized Monomers and Other Starting Substances in Directive 2002/72/EC. No restrictions are included for ethylene and 1-butene. The other two monomers are listed with the following specific migration limits (SML).

1-hexene, SML 3 mg/kg 1-octene, SML 15 mg/kg

Many of the plastics additives used in polyethylene plastics are now listed in Directive 2002/72/EC and some have restrictions assigned.

POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS The following are typical additives used in polyethylene plastics and their “restriction” status: : 4. Additive Restriction

Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxphenyl) None propionate] (antioxidant)

octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate SML = 6 mg/kg

ACKAGING MATERIALS (antioxidant) P phosphorous acid, tri(2,4-di-tert-butylphenyl) None (antioxidant)

erucamide, oleamide, and stearamide None (slip agents)

calcium carbonate, talc, and None (fillers)

glycerol monostearate None (anti-static agent)

N,N-bis(2-hydroxyethyl)alkyl(C8-C18) amine hydrochlorides SML (T) = 1.2 mg/kg (anti-static agents) (expressed as N,N-bis(2- hydroxyethyl)alkyl(C8-C18) amine)

Standard methods for testing polyethylene plastics for compliance with the overall migration limit have been prepared as standard EN 1186 by Technical Committee 194/Sub-Committee 1 of the European Committee for Standardization (CEN). This standard has recently been updated and revised. It was published in fifteen parts as EN 1186 in 2002 (European Committee for Standardization, 2002). The same technical committee is currently preparing standard test methods for the determination of 1-octene in the four standard food simulants (with minor modifications, this test method could be used for 1-hexene). At present there are no standard migration test methods for plastics additives that have legislation restrictions.

14 PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 15 U.S. FDA regulations used in that are of plastic materials for the control own regulations States have their The United (FDA). Substances Administration and Drug by the U.S. Food produced contact with foodstuffs, food additives”. classified as: “indirect are plastics to foodstuffs that may transfer from in the Code of Federal contained are plastics and the co-polymers Regulations for polyethylene may be used in Additives that 21, Part 177.1520, “Olefin polymers”. Title Regulations (CFR) Food 178, “Indirect 21, Part contained in CFR Title and the co-polymers are polyethylene plastics dealing and Sanitizers”. This part contains sub-parts Aids, Adjuvants, Production Additives: agents (3130), clarifying agents antioxidants (2010), antistatic and antifogging with, for example, U.S. the regulations, agents (3860). In contrast with the EC and release (3295), colorants (3297), migration limits for the listed substances. do not contain any specific regulations The FDA as they apply to regulations The full details of these updated annually. are regulations available additives that can be used with these plastics are polyethylene, the , and the site: http://www.access.gpo.gov/nara/cfr/. on the Web The FDA countries that do not have their own often used by non-European are regulations not are that currently used for products sometimes they are In Europe detailed regulations. or a specific national regulation. Directive by an EC covered ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 15 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI RepPolyethyleneforpdf8/04/039:39Page16

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS SAFETY/TOXICOLOGY November 1971).Needed:adequate28dayoralstudy”. hydroxyethyl)alkyl(C8-C18) amine). Available: 90-dayoralratanddog studies(RIVMreport, of theSCF’sopinionis:“Group t-TDI:0.02mg/kg b.w. (as“free” amine)(withN,N-bis(2- amine hydrochlorides. Thissubstancehasbeen placed inSCFList2,andthereported summary valuehasbeendetermined,istheantistaticagentN,N-bis(2-hydroxyethyl)alkyl(C8-C18) SML polyethyleneadditiveforwhichithasbeenpossibletoarriveataTDIvalueandfrom whichan A Tolerable DailyIntake)orat-TDI(=temporaryTDI)hasbeenestablishedbythisCommittee”. September 1986).ThismonomerhasbeenplacedinSCFList2:“SubstancesforwhichaTDI(= Available: a90-dayoralratstudyandmutagenicitystudies(CIVOre. V86.408/251091,26 opinion is:“t-TDI:0.25mg/kgb.w. pendingresults offertilityandteratogenicitystudies. of15mg/kg,thereported summaryoftheSCF’s For 1-octene,whichhasbeenassignedanSML in SCFList3. CS/PM/2742, andRIVMsummarydata,14December1991)”.Thismonomerhasalsobeenplaced screening studyinrats,bioaccumulation(TNO[November 1995]andElias[February 1996]SDS 90-day oralratstudies,inhalationstudy, combinedreproduction/development opinion is:“Available: Migrationdata,5mutagenicitystudiesnegative,28-dayandinadequate of3mg/kg,thereported summaryoftheSCF’s For 1-hexene,whichhasbeenassignedanSML present. EthyleneoxidehasbeenassignedaQMrestriction of1mg/kginDirective 2002/72/EC. are typicallyundetectablesignificantlyreduces thepossibilityofethyleneoxidebeingformedand The factthatethyleneisaveryvolatilegasforwhichresidues inprocessed polyethyleneplastics finished product”. be accepted.Someofthesesubstancesare volatileandtherefore unlikelytobepresent inthe intake (ADI)ortolerabledaily(TDI)couldnotbeestablished,butwhere present usecould The twomonomershavebeenplacedinSCFList3,“Substancesforwhichanacceptabledaily Clayton, 1981). gas haslowtoxicpotential.Migrationintofoodwillbetoxicologicallynegligible”(Claytonand The SCFopinionsforbothmonomersstated:“Residuesofthisgasinplasticsare verysmall.The from processed plastics. toxicological assessmentsandonthefactthatthesemonomersare veryvolatileandeasilylost The decisionsnottoassignrestrictions tothesemonomerswere basedonSCFopinionsfrom the principal copolymerplastics,havenotbeenassignedanyrestrictions inDirective 2002/72/EC. The twomonomers–ethyleneand1-buteneusedinthemanufacture ofpolyethyleneandthe from theplastictofoodstuff (SML).Othersubstancesare assignedaQMrestriction. restriction isaspecificmigrationlimit–onthequantityofsubstancethatmaytransfer necessary, theCommissionappliesarestriction onthebasisofSCFopinion.Inmostcases B Committee onFood(SCF),assessesthetoxicologicalproperties. When 2002/72/EC, theEuropean Commission’sadvisorybody, theScientific efore substancesare placedinthe Authorized ListofDirective 16 PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 17 The above quoted summary data from the SCF assessments and similar data produced for other similar data produced assessments and the SCF data from quoted summary The above plastic monomers and additives can be found in the European Commission’s Synoptic Document, Synoptic Commission’s the European can be found in and additives plastic monomers Plastics and of Manufacture Used in the Additives of Monomers and List Provisional “Draft of of the document is The latest version to Come into Contact with Foodstuffs”. Coatings Intended site: http://cpf.jrc.it/webpack/. available on Web ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 17 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI RepPolyethyleneforpdf8/04/039:39Page18

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS EC Directive on packaging on Directive EC ENVIRONMENTAL ASPECTS techniques are necessarytomakeitsuitablefor reuse asafoodcontactmaterial. high sorptionanddiffusion characteristics.This meansthatrigorous cleaningandpurification properties oftheplastic.Theabove-mentioned project identifiedpolyethyleneasaplasticwith in reverse, todiffuse outintofoodfrom reused orrecycled packagingdependsonthephysical removed. Thepropensity fororganic contaminantstobeabsorbedandretained byaplasticand, new packagingcanbecleaned,buthazardous contaminantsmaynotalwaysbeefficiently with hazardous substancesafteruse.Plasticspackaging intendedtobereused orrecycled tomake made from recycled plasticmaterialisthepossibilitythatoriginalpackagingcontaminated The principalconcernwiththeuseofpreviously usedplasticfoodpackagingand in eitherreused plasticspackagingor madefrom recycled plastics. carried outin-depthstudiestoassesspossiblehealthrisksconsumersfrom foodstuffs packaged During the1990slaboratoriesparticipatinginanEC-fundedproject (European Commission,1997) approvals canbefoundattheWeb site:http://vm.cfsan.fda.gov/~dms/opa-recyc.html. uses. IntheUnitedStates,somedryfoodcontactapplicationshavebeenapproved. Thelistof schemes currently inoperationEurope, therecycled plasticisnotusedfornewfoodcontact HDPE bottles,however, canbeeasilycollectedandtheplasticrecycled. With bothfilmandbottle other commodities,itispossibletosetuppracticalcollectionandrecycling schemes. films usedasoverwrapsandlinersforbulktransportoffresh andpackagedfoods,beverages, make apracticalcontributiontomeetingrecycling targets forplastics.However, forpolyethylene Collection andrecycling ofpolyethylenefilmpackagingfrom retail-sold foodsare unlikelyeverto reuse and Recyclability contact plastics,andtheoverallsafetyoffoodstuff. it uptotheuserensure fullcompliancewiththeECDirectives, nationalregulations onfood European countriesvaries,withsomeforbiddingtheuseofrecycled materialsandothersleaving materials andarticlesmadefrom recycled plastics.Theregulatory situationinindividual is 20%. An extendedtimeconcessionmaybegiventosomeMemberStatesmeetthesetargets. 70% byweight.Different classesofmaterialsare givendifferent recycling targets—that forplastics by 2006anoverallrecovery target of60to75%byweightandanoverallrecycling target of55to increasing thetarget percentage values.Proposals putforward attheendof2001wouldrequire Union MemberStatemustachieve.Thesetargets are currently underreview withtheintentionof functioning oftheinternalmarketthereby avoidingbarrierstotrade”. management inorder toprovide ahighlevelofenvironmental protection aswelltoensure the of theDirective isto“Harmonisenationalmeasures concerningpackagingandwaste plastic packagingisECDirective 94/62/ECon“PackagingandPackagingWaste”. Thebasicaim At present, there are noECDirectives orregulations thatapplyspecificallytofoodcontact The Directive specifiespackagingwasteandrecycling targets thateachindividualEuropean The principalEuropean Unionenvironmental legislationaffecting manufacturers andusersof 18 PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS thylene E oly P 19 ensity D ow- L ., 1985; Kroschwitz, 1998). ., 1985; Kroschwitz, thylene E et al ., 1998; Huber and Franz, 1997). ., 1998; Huber and Franz, oly P et al HDPE LDPE ensity D igh- H In 1998, ILSI Europe published a report from a workshop meeting of the ILSI Europe Packaging of the ILSI Europe a workshop meeting from published a report In 1998, ILSI Europe of for the safe recycling guidelines which had been convened to produce Force, Materials Task Institute, 1998). The two principal use (International Life Sciences plastics for food contact should be used as the only food-grade plastics specified in the guidelines are: requirements chemicals, representing with surrogate a challenge test should be performed feedstock and that and processing cleaning, heating, to demonstrate that after prescribed likely contaminants, migration” of such contaminants. would be “no detectable operations, there purposes, polyethylene plastic packaging often carries the following For collection and recycling symbols, which identify the plastics as either high-density internationally recognised the letters “HDPE” or as low-density polyethylene with polyethylene with the number “2” and two necessary to enable the The two symbols are the number “4” and the letters LDPE. of recycled which in turn enables the useful production polyethylene types to be segregated, plastics. The symbols are typically found on the base of bottles and other containers. They are usually not typically found on the base of bottles and other containers. They are The symbols are most of this type of packaging films, as it is not practical to collect and recycle on retail present has been development work often ends up as , waste. For such waste, which either photodegradable or biodegradable. plastics that are polyethylene to producing directed and Ethylene–carbon monoxide copolymers have been found to be photodegradable, have been found to be biodegradable. However, polyethylene formulations with added use for food into mainstream these modified polyethylene plastics have not been brought packaging (Mark As polyethylene and the co-polymer plastics are hydrocarbon polymers, incineration produces hydrocarbon As polyethylene and the co-polymer plastics are plastics fuels. The small quantities of the hydrocarbon similar to those from combustion products only small amounts of other combustion additives and the coatings or barrier layers produce for disposal of polyethylene plastics. It also process an effective Incineration is therefore products. for heating or to generate electricity. that can be used energy produces Incineration with energy recovery Further studies of HDPE bottles have concluded that it may be possible to use the recycled plastic to use the recycled that it may be possible have concluded of HDPE bottles Further studies or processes cleaning efficient to specific highly has been subjected either after it for food contact two outer layers plastic as the with virgin sandwich three-layer layer in a as the centre (Devlieghere ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 19 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI RepPolyethyleneforpdf8/04/039:39Page20

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS GENERAL CONCLUSIONS is effectively maintained. aluminium, toprovide sealablepackagingthatensures thatthequalityofpackagedfoodstuff simple plasticfilmbagstocombinationswithotherplasticsormaterials,suchaspaperboard and relatively lowcost.Therangeofpackagingformsforwhichpolyethyleneisusedextendsfrom with whichitcanbemanufactured andconvertedintoavarietyofpackagingforms,its Polyethylene achieveditsdominantpositionbecauseofrangeversatileproperties, theease in polyethylenebecomingthedominantplasticmaterialforfoodandbeveragepackaging. S over theyearshaveproduced afamilyofplasticswhichhaveresulted find wideuseasapackagingmaterialforfoodstuffs, developments ince the1950s,whenpolyethylenebecamefirstplasticmaterialto 20 PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS , , Blackie , John Wiley Food Additives & (3):336-345. 15 (11):213-216. 30 (10):328-331. 83 Deutsche Lebensmittel-Rundschau Packaging Technology and Science Packaging Technology Migration from Food Contact Materials Migration from (3):323-337. 7 21 , Taylor and Francis, London, UK, , Taylor , Emap Maclaren, Croydon, UK, Croydon, , Emap Maclaren, :261-270. 10 European Plastics News European Food Additives & Contaminants , Taylor and Francis, London, UK, , Taylor REFERENCES Anonymous (2001). USA, York, & Sons, New Devlieghere, F., De Meulenaer, B., et al. (1998). Evaluation of recycled HDPE milk bottles for food B., et al. (1998). Evaluation of recycled De Meulenaer, F., Devlieghere, applications, Ashford, R.D. ed. (1994). Ashford’s Dictionary of Industrial Chemicals. Wavelength Publications, Dictionary of Industrial Chemicals. Wavelength Ashford’s R.D. ed. (1994). Ashford, 394, 468, 646, 734-735. Ltd., London, UK, 148, 2nd Packaging Technology, Encyclopaedia of (1997). Wiley A.L. and Marsh, K.S., eds. Brady, USA, 749., 754 York, & Sons, New edition, John Wiley Dekker Marcel design & fabrication, Plastics in Food Packaging: properties, ed. (1992). W.E. Brown, 107. USA, York, Inc, New ed., 3rd Hygiene and Toxicology, eds. (1981). Patty’s Industrial Clayton, G.D. and Clayton, F.E., USA. York, & Sons, New John Wiley Investigations on overall migration of various plastic Czerniawski, B. and Pogorzelska, Z. (1997). foodstuffs, materials and articles used in contact with European Commission, DG XII (1997). Programme to Establish Criteria to Ensure the Quality and to Ensure to Establish Criteria DG XII (1997). Programme Commission, European & Food Packaging. Final Report, DG XII Science, Research Safety in Use of Re-Cycled Plastics for Belgium. Brussels, Commission, AIR2-CT93-1014, European Development Project. articles in contact with (CEN) (2002). Materials and for Standardization Committee European Belgium, Standard 194/Sub-Committee 1, CEN, Brussels, Committee Technical Plastics, foodstuffs: ENV 1186. Figge, K. (1996), Chapter 5 Plastics, in Katan, L.L. ed. UK, 77-110. Glasgow, Academic & Professional, Munich, Verlag, Additives. 4th edition, Carl Hanser H. (1993). Plastics R. and Müller, Gächter, 8, 48-62, 439-440, 472, 555-556, 754. Germany, , migration of antioxidants from Goydan, R. (1990). High temperature Contaminants J.D. (2000). Plastics Packaging, Carl Hanser Verlag, Hernandez, R.J., Selke, S.E.M., and Culter, 100-101, 199-208, 213. Munich, Germany, controlled of post consumer plastics from M. and Franz, R. (1997). Studies on contamination Huber, into food packaging applications, for recycling resources Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, Germany, mbH, Stuttgart, Germany, Verlagsgesellschaft Wissenschaftliche ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 21 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI RepPolyethyleneforpdf8/04/039:39Page22

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS Munich, Germany, Zaby, G.(2001).Plasticsremain agrowth industry, York, USA,320. Rubin, I.I.ed.(1990).HandbookofPlasticsMaterialsandTechnology, JohnWiley &Sons,New McGraw-Hill, New York, USA, Parker, S.P. ed.(1997).McGraw-HillEncyclopaediaofScienceandTechnology, 8thedition, John Wiley &Sons,New York, USA, Mark, H.F., Bikales,N.,etal.(1985).EncyclopaediaofPolymerScience&Engineering,2ndEdition, Additives &Contaminants density polyethyleneandpolypropylene intoaseriesofpotentialfatty-foodsimulants, Lickly, T.D., Bell,C.D.,andLehr, K.M.(1990).ThemigrationofIrganox 1010antioxidantfrom high Publications PVT. Ltd.,Prabhadevi-Mumbai,India, Kulshreshtha, A.K. (2001).NewGenerationofPolyethylenes, & Sons,New York, USA, Kroschwitz, J.I.(1998).Kirk-OthmerEncyclopediaofChemicalTechnology, 4thedition,John Wiley Contact Use,ILSIPress, Washington, D.C.,USA. International LifeSciencesInstitute(European Branch)(1998).RecyclingofPlasticsforFood 91 (10):84-86. , Taylor andFrancis,London,UK, 11 : 843-845and 14 :194–197. 6 :384-385, 410. 17 :704, 707,723,743. 22 46 Kunststoffe PlastEurope (6):73-76. 7 (6):805-814. Popular PlasticsPackaging , KarlHanserVerlag, , Colour Food PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 23 Coca-ColaCognis DanoneGroupe Dow Europe Frito Lay Europe Nestlé Services Swiss Quality Testing Numico Research Corporation Valspar Acknowledgments Acknowledgments for writing this Tice P. thank Dr. would like to Force Material Task and the Packaging ILSI Europe report. the industry members by an unconditional grant from and supported This work was coordinated Force. Task Packaging Material of the ILSI Europe call (+32) 2 771 00 14 or e-mail: [email protected] For further information about ILSI Europe, the views and do not necessarily represent those of the author are herein The opinions expressed of ILSI Europe. ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 23 Page 9:39 8/04/03 pdf for Polyethylene Rep ILSI ILSI RepPolyethyleneforpdf8/04/039:39Page24

PACKAGING MATERIALS: 4. POLYETHYLENE FOR FOOD PACKAGING APPLICATIONS 24 ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 25

Other ILSI Europe Reports

• Addition of Nutrients to Food: Nutritional and Safety Considerations • An Evaluation of the Budget Method for Screening Intake • Antioxidants: Scientific Basis, Regulatory Aspects and Industry Perspectives • Applicability of the ADI to Infants and Children • Approach to the Control of Entero-haemorrhagic Escherichia coli (EHEC) • Assessing and Controlling Industrial Impacts on the Aquatic Environment with Reference to • Assessing Health Risks from Environmental Exposure to Chemicals: the Example of Drinking Water • ß-Carotene, E, Vitamin C and Quercetin in the Prevention of Generative Diseases – The role of foods • Detection Methods for Novel Foods Derived from Genetically Modified Organisms • Exposure from Food Contact Materials • Food Additive Intake – Scientific Assessment of the Regulatory Requirements in Europe • Foodborne Viruses: An Emerging Problem • Food Consumption and Packaging Usage Factors • Management Tools • Functional Foods – Scientific and Global Perspectives • Markers of Oxidative Damage and Antioxidant Protection: Current status and relevance to disease • Method Development in Relation to Regulatory Requirements for the Dectection of GMOs in the Food Chain • Overview of Health Issues Related to Alcohol Consumption • Overweight and in European Children and Adolescents: Causes and consequences – prevention and treatment • Packaging Materials: 1. Polyethylene Terephthalate (PET) for Food Packaging Applications • Packaging Materials: 2. Polystyrene for Food Packaging Applications • Packaging Materials: 3. Polypropylene as a Packaging Material for Foods and Beverages • Recycling of Plastics for Food Contact Use • Safety Assessment of Viable Genetically Modified Micro-organisms Used in Food • Safety Considerations of DNA in Foods • Typhimurium definitive type (DT) 104: A multi-resistant Salmonella • Significance of Excursions of Intake above the (ADI) • The Safety Assessment of Novel Foods • Threshold of Toxicological Concern for Chemical Substances Present in the • Validation and Verification of HACCP

To order ILSI Europe Avenue E. Mounier, 83, Box 6 B-1200 Brussels Belgium Phone: (+32) 2 771 00 14 Fax: (+32) 2 762 00 44 E-mail: [email protected] ILSI Rep Polyethylene for pdf 8/04/03 9:39 Page 26

The International Life Sciences Institute (ILSI) is a nonprofit, worldwide foundation established in 1978 to advance the understanding of scientific issues relating to nutrition, food safety, toxicology, risk assessment and the environment. By bringing together scientists from academia, government, industry, and the public sector, ILSI seeks a balanced approach to solving problems of common concern for the well-being of the general public. ILSI is head-quartered in Washington, DC, USA. Branches include Argentina, Brazil, Europe, India, Japan, Korea, Mexico, North Africa and Gulf Region, North America, North Andean, South Africa, South Andean, Southeast Asia Region, the focal point in China and the ILSI Health and Environmental Sciences Institute (HESI). ILSI is affiliated with the World Health Organization as a non-governmental organisation (NGO) and has specialised consultative status with the Food and Agriculture Organization of the United Nations.

ILSI Europe was established in 1986 to identify and evaluate scientific issues related to the above topics through symposia, workshops, expert groups, and resulting publications. The aim is to advance the understanding and resolu- tion of scientific issues in these areas. ILSI Europe is funded primarily by its industry members. ISBN 1-57881-155-4 ILSI Europe Avenue E. Mounier, 83, Box 6 B-1200 Brussels ,!7IB5E4-ibbffa! BELGIUM Phone: (+32) 2 771 00 14 Fax: (+32) 2 762 00 44 E-mail: [email protected]