A review of the availability of plastic substitutes for

A Review of the Availability of Plastic Substitutes for Soft PVC in Toys By Joel Tickner Department of Work Environment University of Massachusetts at Lowell USA.

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A Review of the Availability of PlasticSubstitutes for Soft PVC in ToysDepartment of Work EnvironmentUniversity of Massachusetts at Lowell, USATable of ContentsSummarySection 1: IntroductionSection 2: Background - plastics use in toysSection 3: Plastic processing techniques for toysSection 4: Material requirements for Section 5: A comparison of various plastic alternatives to PVCSection 6: Lifecycle considerations for alternative plasticsSection 7: Cost analysis of alternativesSection 8Appendices: - Plastic additives used in toys - The hierarchy of plasticsReport Commissioned by Greenpeace InternationalFebruary 1999
SummaryGreenpeace commissioned this report to answer the question - Are there viablealternatives readily available that can be used as substitutes for soft PVC in toys? Ourconsultant utilized the expertise of polymer scientists to create this review of theavailable alternative materials. The question was answered definitively that substitutesexist today which are safer and cost competitive. Only lacking is the will of an individualcompany to accept the challenge and select appropriate materials that meet therequirements of the toy industry. This report is made available to move the debateforward constructively to ensure the safety of all children.SummaryThe current debate around soft polyvinyl chloride (PVC or vinyl) toys focuses onwhether the risk to children from exposure to hazardous additives that leach during use issignificant enough to warrant immediate or long-term restrictions or prohibitions of thisplastic. Soft PVC contains up to 50% by weight of plasticizers, usually phthalate esters,which are not chemically bound to the plastic and therefore leach or migrate. Laboratorystudies demonstrate that the phthalates may cause cancer and reproductive harm, andemerging evidence points to some phthalates as possible hormone disrupters.Scientists know very little about how the phthalates might affect a child's health,and direct evidence proving harm as a result of exposure to phthalates in soft PVCtoys is impossible to obtain without conducting controlled experiments on childrenand looking for adverse effects throughout their lifetimes. What is known, however,is that children are exposed to phthalates from other sources in addition to soft PVC toys.Acknowledging this, it is important to note that there are viable alternatives to soft PVCin toys. Why take a risk at the most critical stage in a child's development? Why focuson what a "safe" level of phthalate exposure to a child might be, when this isfundamentally unknown? The terms of the debate, thus, must shift and focus not on hazardous exposure to phthalates is but rather on whether there are safer substitutes forPVC and how these can be implemented.Political ContextIn the European Union (EU), the hazards of soft PVC toys were brought to the attentionof the European Commission almost two years ago by Danish authorities whorecommended the withdrawal of three PVC teething rings which leached phthalatesofteners. Recommendations for voluntary withdrawals of soft toys containing phthalateshave also been made by the Dutch, German, Belgian, Canadian, Philippines and UShealth or consumer protection authorities. Bans on phthalates in soft PVC toys havebeen initiated or are in place in Austria, Denmark, Sweden, Norway, Greece and Mexico.In March 1998, after withdrawing several soft PVC teething rings from the market, theSpanish government requested that the Commission take EU-wide emergency action to
address the hazards from soft PVC toys. In June 1998, the European Commission'sConsumer Protection Directorate put forward a proposal for a temporary, emergency banon certain soft PVC toys for children under three, which are designed to be put in themouth and which contain certain phthalates.Despite agreement by the Commissioners that protective measures were necessary, theyhave failed to agree on a proposal for an emergency ban. The Commissioners did agree,however, on the need for long-term legislation to address the problem. Followingreconfirmation by a scientific committee that soft PVC toys and childcare articles canpose a health concern, calls for an emergency ban have been renewed this year.In the meantime, numerous companies have initiated plans to ensure that either phthalate-free or PVC-free products are available this year. While this is encouraging, concernremains that several major companies will continue to use PVC and simply replacephthalates with other additives, which could also be used in large quantities, leach outand be potentially hazardous.A phase out of the use of PVC in the toy industry is possible in the near future. For thetoy industry, PVC is not a major material. It represents only 4.5% of plastics use in toys.For the PVC industry, the use of PVC in toys represents a minute proportion of PVCproduct, less than 0.1% by weight of the total PVC market in Europe. The proportion ofteethers or articles designed to be put into a child's mouth will represent only a minorAlternatives to soft PVCIn the selection of alternatives for soft PVC toys, consideration must be given toenvironmental and health impacts of the material throughout its entire lifecycle. Thereare several natural materials that have traditionally been used to make toys and teethers,such as wood and textiles. These materials are well tried and tested over the years, areusually durable and repairable and are used by many companies. These materials arepreferred to any petrochemical-based plastics because of the global environmentalimpacts of the use of non-renewable fossil fuels. Given that the toy industry willcontinue to use soft plastic for certain items, it is necessary to identify plastics which arepreferable to soft PVC.In the long term, bio-based polymers, made from renewable sources, are preferable to anyof petrochemical plastics for products which have relatively short lifecycles such as toys.In the interim, until bio-based plastics are widely available, there are some petroleum-based plastics which are less harmful to the environment and which do not pose such adirect threat to children's health as soft PVC. Many of these plastics are already beingused by toy manufacturers for certain products, such as teething rings and soft blocks.This report examines three types of plastics as potential replacements for soft PVC intoys: Thermoplastic elastomers (TPEs), ethylene vinyl acetate (EVA) and polyolefins
(polyethylene/polypropylene), including the new metallocenes. All three materials fulfillsafety requirements, ease of processing (if possible on the same equipment as PVC);aesthetic appeal, lessened environmental and health impacts; and cost competitiveness.The use of these materials to replace soft PVC is a significant improvement andrepresents progress toward sustainable materials. The three alternative plastics, includingcost comparisons, are summarized in the table.A summary of PVC alternatives for toysPlasticFlexibilityProcesstechniquesReplacementtypesCost/lb.(in dollars)Environmental
Thermoplasticelastomers:StyrenicPolyolefinAlloys TPUswide, dependson co-polymeror blend typeand amountsblow molding,extrusion,calendering,rotationalmolding,thermoformingTeethers, dollparts/figures,squeeze toys,possiblyinflatable toys0.85-1.87depending ontype and blendor co-polymermixtureChemicals used:styrene andpolyurethaneproductionarehazardous andboth off-gastoxic chemicalsin fires
EVAwide, dependson VA contentof polymersheet extrusion,injectionmolding,rotationalmoldinginflatable toys,teethers,possibly dollparts0.50-0.80chloride catalystused in somevinyl acetateproduction, by-products fromethyleneproduction
Polyethylenes,Polypropylene,blends/alloys,metallocenecatalyzedpolyolefinswide, dependson chainlength, co-polymer orblendall majorprocessingtechniquesall current PVCtoyapplications0.40-0.550.55-0.60metalloceneproductsby-productsfrom ethyleneproduction
In addition, none of these alternatives requires phthalate plasticizers to be soft andflexible (although they could be used and care should be taken to prevent this) and allrequire less overall additives than PVC. When they do contain additives, these additivesmake up a much smaller percentage (0-2% of the polymer mixture), in comparison to upto 50% phthalate content in PVC toys. Furthermore, it appears that the alternatives arealso less likely to leach than PVC as the additives are bound tighter to the polymer.When additives are required for compounding the alternative materials, those thatare non-toxic and are not endocrine disrupters should be used to reduce hazards.It is important that thorough testing of all materials to be used for toys isundertaken, and that regulations prevent the use of hazardous additives such asphthalates in any material intended for children.Once potential replacements are examined to meet toy material requirements, it is alsoimportant to consider the long-term environmental impacts of the alternatives. Byranking plastics in a pyramid, from worst to best, it is possible to evaluate materials froma lifecycle perspective, in an effort to select the most appropriate plastic.
Greenpeace has created such a pyramid with PVC at the top as the most environmentallydamaging of the plastics. [1] The hierarchy is as follows:
The Greenpeace Plastics Pyramid of ProblemsThis report demonstrates that rather than spending resources on only assessing the risksof phthalate plasticizer in PVC toys, at the potential detriment to children, attentionshould focus on which alternatives can be developed and selected to replace PVC in toys.In the meantime, soft PVC toys should not be permitted for sale or use, in line with theprecautionary principle. This states that when there is evidence of potential harm, theexposure should be eliminated despite the lack of clearly proven cause-effect1 See Wytze van der Naald and Beverley Thorpe, PVC Plastic: A Looming Waste Crisis, GreenpeaceInternational, 1998.
Section 1: IntroductionThe current debate around polyvinyl chloride (PVC or vinyl) toys focuses on whether therisk to children from exposure to softeners (plasticizers) known as phthalate esters whichleach during use is significant enough to warrant restrictions or prohibitions of thisplastic. Laboratory studies demonstrate that the phthalates may cause cancer andreproductive harm, and emerging evidence points to some phthalates as possible hormoneScientists know very little about how phthalates might affect a child's health, and it isvirtually impossible to follow a child throughout his/her lifetime to determine whetherexposure to phthalates from a toy caused harm. What is known, however, is that childrenare exposed to phthalates from other sources in addition to soft PVC toys, such as in food(including infant formula), dust and air.Acknowledging this, it is important to note that there are viable alternatives to PVC intoys. Why take a risk at the most critical stage in a child's development? Why focus onwhat a "safe" level of phthalate exposure to a child might be when this is fundamentallyunknown? The terms of the debate, thus, must focus not on hazardous exposure tophthalates is but rather on whether there are safer substitutes for PVC and how these canbe implemented.Some toy companies and retailers have taken precautionary action by removing soft PVCtoys from their product line. For example, the Lego company has eliminated most of itsPVC products and has issued a statement of intent to eliminate those remaining. Othercompanies taking precautionary action include Little Tikes of the US, Ambi Toys of theNetherlands, Tolico of Denmark, Babelito of Argentina and Chicco, Prenatal and GiochiPreziosi of Italy.This report provides an analysis of existing plastic alternatives to replace soft PVC intoys. This report does not cover PVC replacement by other materials such as cloth, woodor bio-based plastics, which may serve as better long term alternatives, nor does itexamine issues of consumption or waste from the production and use of toys. Directsubstitution for soft PVC toys, such as blow-up/inflatables, teethers and pacifiers,squeeze toys, and dolls are the focus of this analysis since hard PVC applications, such asstacking blocks, are minimal and easily substituted with numerous alternatives.Following an overview of plastics use in toys and material requirements in toymanufacture, a detailed analysis is provided of three types of plastics that have beenidentified which could immediately replace PVC in the majority of soft toy applications.This overview covers applications, limitations, and use of additives. Also provided is acost-comparison and overview of environmental considerations for the alternatives.The alternative plastics to soft PVC toys presented in this report are also applicable asreplacements for other flexible PVC applications such as medical devices, packaging,
other sheeting applications, etc. The replacement of PVC in other applications willrequire an analysis of specific product requirements and processing needs.Section 2: Background - Plastics Use in ToysThe era of plastics use in toy production began in 1868 when John Wesley Hyattdiscovered cellulose nitrate which served as a substitute for expensive and ecologicallydamaging ivory billiards balls. By the turn of the century, plant based plastics were usedwidely in doll production. Since the 1950s petrochemical-based plastics have beenincreasingly used in the toy industry. Currently, plastics are used in more than 80% of allnew toys made.In many respects, plastic materials are cheaper, easier to process, and have more colorpossibilities than the conventional toy making materials like clay, metals, ceramic, andwood. However, with this increasing use of petroleum-based plastics in toys also comesconcerns over impacts to children's health from plastics additives and environmentalconcerns over plastic production and disposal.The most commonly used plastics to make both soft and rigid toys are commodity resinslike High Density Polyethylene (HDPE), Polypropylene (PP), Polystyrene (PS), andPolyvinyl Chloride (PVC). Other resins like Polyamid (PA) Nylons, AcrylonitrileButadiene Styrene (ABS), Acetal resins (Poly oxymethalate, POM), Poly MethylMethacrylate (PMMA, or Acrylics), Polycarbonate (PC), Polyurethane (PU), are alsoused according to the properties required for a particular toy.The use of PVC in toy production (only approximately 4.5% of plastics use in toys) cameunder scrutiny in the early 1980s due to the possible adverse health effects associatedwith a particular softener, Di(2-ethylhexyl) phthalate (DEHP). Following a U.S.Consumer Product Safety Commission investigation into health risks from DEHPexposure, in 1986 the Toy Manufacturers of America entered into a voluntary standardwhich allowed no intentional addition of DEHP into pacifiers, rattles and teethers (amaximum of 3% by weight). [2] This resulted in its replacement with other phthalatesofteners, for which mounting evidence points to risks to children.Environmental problems can be associated with all synthetic plastics, from production todisposal; however, PVC has the greatest impact on the environment and on healththroughout its lifecycle. PVC is also linked to the formation of dioxins and dioxin-likecompounds when short-life applications such as toys, disposable medical applications,and packaging are incinerated as a disposal method. [3] PVC production has also beenidentified as a large source of dioxin and other persistent organic chemicals.The hazards posed by PVC to human health and the environment throughout its lifecycle(production, use, and disposal) necessitate the identification of safer and moreenvironmentally preferable materials to replace the PVC fraction used in the toy industry.Lifecycle considerations of alternative plastics are discussed in Section 6 and an
evaluation of the environmental impacts of the various petrochemical plastics, which areranked in a pyramid from worst to best, is included in Appendix B.2 Report to the U.S. Consumer Product Safety Commission by the Chronic Hazard Advisory Panel onDi(2-ethylhexyl) Phthalate (DEHP), September, 1985.3 See Pat Costner, The relationship between chlorine input and to combustors and dioxin output,Annotated bibliography, Greenpeace International, April, 1997 for an overview of the scientific studiessupporting a PVC/dioxin link in incineration. Available on the Greenpeace Web Page,www.greenpeace.org.Section 3: Plastic Processing Techniques forToysA wide variety of processing techniques have traditionally been used in plastic toyproduction. Table 1 presents some of these processes, the materials used and typical usesin the toy industry. [4] As noted, while PVC use in toy production is very limited, its usehas been predominant in the production of certain types flexible products (especiallysheets for inflatable toys and doll's heads) because of its ease of processing using certaintechniques and ability to accept additives to achieve specific qualities. The alternativesdescribed in Section 5 can also be processed using common processing techniques, and attimes on the same equipment as PVC toys, with process modifications.As an example, inflatable toys such beach balls, wading and swimming pools, boats andfloats, and stand up figures are frequently made by cutting and sealing plasticized PVCsheet. Materials like ethylene vinyl acetate (EVA) and novel metallocene catalyst basedPolyethylenes, which allow simple, joining techniques like radio frequency (RF) weldingrepresent useful substitutes to plasticized PVC sheets.TABLE 1. Common processing techniques in the toy industry.TechniqueTypical PlasticsTypical Application
Injection moldingPolystyrene (PS), Acrylonitrile-Butadiene-Styrene (ABS), PVC and all kinds ofthermoplasticsBlocks, solid parts, model kits
Blow moldingHigh Density Polyethylene (HDPE), PVCWheels, hollow parts, figures
Rotational moldingEmulsion PVC, HDPEDoll parts, squeeze toys
ThermoformingPS, Polyethylene (PE), Polypropylene (PP),Polyethylene Terephthalate (PET), Ethylenevinyl acetatePlaying boards, play sheets
CalenderingPVCSheet for inflatable toys
Sheet extrusionPS, PVCSheet for thermoforming and forinflatable toys
Coated fabricsSeveral plastics, usually PVC coated polyesterCloth substitutes, soft doll bodies
FoamingPolyurethane, polystyreneSoft balls, surfboard filler
Biaxial orientationXLPE, PS sheetShrink wrap and other items
DippingPVC, latexHandle grips, balloons
Slush moldingEmulsion PVC, polyethyleneDolls, boots and other clothing
Some of the different processing techniques are described below, the most important ofwhich for toy production are injection molding (hollow/filled objects) and extrusion:Injection molding: Plastic material is melted using heat and shear energy and injectedunder pressure into a mold to achieve the required shape. Building blocks, figurines,hard/flexible teethers, and other types of toys are produced using this technique.Blow molding: A continuous tube of plastic material is extruded using heat and pressure.The tube, called a 'parison', is then blown with pressurized air to achieve a shape, inside aclosed mold. Most of the dolls, soft balls, and hollow toys are made using this technique.: Plastic material is heated until the particles fuse, and while thisfusion takes place, the closed mold is rotated in the minor and major axes to achieve auniform wall thickness. Toys such as plastic boats, figure busts, dolls heads, and largehollow toys are made using this technique.Thermoforming: The plastic sheet is heated just below its softening temperature, andthen pressure is placed on it with a male and/or female mold to produce a shape. Pressureand vacuum can be used to achieve maximum wall thickness, uniformity, and strength.Plastic materials are also processed in a rubbery state using this technique. Thistechnique is used to make toy trays, cups, masks, and boards.Sheet Extrusion: Molten plastic materials are continuously extruded through a die toform sheets. Generally this method is used for making rigid sheets used inthermoforming. Films and tubes can also be made through extrusion.Calendering: Sheets are made using a continuous, synchronized method which convertsraw materials, fuses the sheets and then passes them through the nips of a series of rolls.This process can be used with PVC and ABS (acrylonitrile-butadiene-styrene), as well aspolyethylene and polypropylene. These flexible sheets are used to make toys suchinflatable beach balls. Calendering is often a second step after extrusion.: A liquid gel of plastics is applied on the mold surface and a number of layers ofreinforcing agents, such as glass fibers, are added to form an article. This technique isused to make toys of with intricate shapes and contours which would be difficult to makeusing conventional techniques.Dipping: This is a simple technique of dipping the mold into a plastic solution andfusing the coating to make the article. Soft flexible toys such as balloons, handle gripsand flexible covers can be made using this technique. It is often used in latex processing.Slush molding: This is a useful technique to produce hollow objects which involvesfilling a hollow mold with a solution of plastic material, exposing the mold to heat,gelling an inner layer or wall of material in the mold, inverting the mold to pour out the
excess liquid material, and heating the mold to fuse the material. The mold is then cooledand the finished part removed.The following sections discuss the functional requirements of materials used in toys andthe types of materials which could replace PVC.4 See Mark, et. al, Encyclopedia of Polymer Science and Engineering, John Wiley & Sons, 1989 for adetailed overview of plastics use in toys.Section 4: Material Requirements for ToysIn general, design requirements and characteristics needed for a particular product (how itwill be used, colorfastness, stability under harsh conditions) as well as ease of processingand overall cost, will drive the choice of material used in producing a particular toy. Intoday's competitive toy market, cost containment will often take precedent over otherfactors.Nonetheless, most designers will consider a series of material requirements beforedesigning a toy or replacing one material for another. PVC replacement in toys could beachieved by two methods: design of new products with different characteristics orsubstitution of PVC for other materials in the same product. Common factors to beconsidered in material selection are listed below.Some of the important requirements for alternative materials include: avoidance of toxicor endocrine disrupting additives, and none or minimal leachables; safety (avoidance ofchipping and breaking); strength and durability under various conditions of use; ease ofprocessing; aesthetic appeal; cost competitiveness; and environmental and health impactsthroughout the lifecycle of the alternative material.Durability/Safety/Operating Conditions: Toys are generally expected to be strongso as to not chip, incur stress cracking, or break and resist abrasion. Alternativematerials should have high strength, rigidity, and resistance to creep (deformation ofthe polymer).Since a large fraction of toys are used outdoors, the material must have goodweatherability (temperature and weather extremes) and ultraviolet (UV) stability.Generally, unstable chemicals and weak bonds are more prone to oxidative cleavagewhich initiates a chain reaction of degradation. The plastic material should thus bechemically stable to withstand degradation. The alternative should also be resistant towater, solvents, oils and chemicals which may be reactive with the plastic (with thematerial and/or the additives). Durable toys will last longer and will not end up asquickly in the landfill or incinerator.
Avoidance of toxic or endocrine disrupting additives which might leach during: In addition to being non-toxic to a child when ingested or under other conditionsof exposure, the material should use none or only minimal amounts of non-toxicadditives, eliminating or maintaining leachability as low as possible.Flexibility/resilience: Toys must be made flexible yet tough enough to withstandabuse and prevent breakage. Resistance to repeated flexing (fatigue resistance) andan ability to retain the product shape after repeated use may also be critical. A varietyof properties combine to make a plastic flexible, such as the types of molecularbonds, crystallinity, plasticizer, humidity, and secondary attraction forces (e.g., sterichindrance and polarity).Economics: Cost-competitive. Alternative materials should have a high strength toweight ratio, meaning that less material can be used to produce a product of similarstrength. When more than one material is available for a toy, the choice of materialoften becomes a matter of economics. However, environmental and health and safetyconsiderations should be paramount.Ease of processing and processing problems: As every cent is accounted for in thiscompetitive industry, alternative materials must be easily processed by conventionaltechniques with normal processing equipment or on the same equipment as PVC toymanufacture. Also, difficulties in processing of alternative materials and the ability toovercome those difficulties must be considered.Aesthetic appeal: A major requirement for consumer products such as toys is theirappearance. This is the single largest contributing factor to product survival.Materials must have a wide array of color compatibility and a rich 'feel'.Regulations and specifications: Designers must meet international or nationalgovernment regulations or industry specifications concerning the use of materials intoys. Usually considered in such regulations and specifications are additive content,flammability, food contact, and leachates.Other material/fabrication requirements: Material properties to consider includeelectrical insulation properties, transparency, frictional properties, surface finish andspecific gravity. Processing requirements include the need for assembly or coating,paintability/colorability, or any post molding operations required.: Since children can ingest toys, especially if small parts areinvolved, plastics can be made radiopaque and x-ray visible by chemically bindingbarium salts to polymer chains. This aids detection if swallowed.In the end, cost will be the determining factor in choosing between two similar materials,if other considerations such as environmental, health and safety are equal. Costconsiderations, however, need to include both actual material cost on a per weight basisin addition to gains from material conservation and process conditions.
Section 5: A Comparison of Various PlasticAlternatives to PVCBased on the requirements for specific toys, various materials can be selected as potentialalternatives to PVC. The materials listed below represent three types of readily availableplastic alternatives which fulfill the material considerations listed in the previous section.Some of these alternative materials are currently being widely used, while some arenewly developed with advance technology, and are only now entering the market. Noneof the three alternative plastics require the large quantity of additives required to softenPVC. Nonetheless, toy manufacturers should undergo a detailed examination ofalternative materials for their health and safety and environmental impacts beforeselecting a new plastic.All of the alternative plastic materials addressed (in fact the vast majority of plastics onthe market today) are petrochemical based and thus cannot be considered sustainable inthe long term due to limits in resources and the contribution that petrochemicalproduction makes to global climate change. Substitutes have been chosen to addressimmediate concerns of children's health and safety and minimizing product lifecycleenvironmental impacts.The question of additivesAll plastics, including bio-based plastics, require the use of additives to aid processing,enhance material properties (reinforce), reduce material costs (fillers) and impart specificcharacteristics such as stability (heat and light), flexibility, flame resistance, provide colorand aesthetics, etc. Because of its brittle nature and heat sensitivity, PVC by far uses thegreatest amount of additives of any commercial resin. For example, the vast majority ofall stabilizers are used in PVC (because of its susceptibility to dehydrochlorination) aswell as 90% of global plasticizer use and 95% of all phthalate use (some 1.4 billion lbs.per year).When plastics are used, there is always a possibility that incorporated additives maymigrate in small amounts to product surfaces, and into the surrounding media. Thusmigration may lead to some human exposure to additives. This migration or leachingfrom the polymer molecules to the surface, may vary widely depending upon: type ofplastic matrix; diffusion properties of the additive in the plastic matrix; contactenvironment, time, and temperature; interaction between different additives, andconcentration of additives.Below is a short generic summary of plastics additives. These are described in greaterdetail in Appendix A. External paints, pigments, and adhesives are not considered. It isimportant to note when additives are required for compounding the alternative materials(specific characteristics cannot be achieved through polymer modification), non-toxicalternatives should be used to reduce risks to children. Also, plastics additives may affect
polymer properties, so when possible, it is useful to minimize their use, as well aseliminate those that are toxic or endocrine disrupting.Table 2: Additives used in plastic productionAdditive typeReason for useChemical(s) used% by weight ofpolymerMain plasticsusing additive
PlasticizersSoften/addflexibilityphthalates, adipatesepoxidized soy oil,phosphates, trimellitatesdepends onflexibilityneeded, up to60% or morePVC, sometimesused but notrequired with otherpolymers andthermoset rubbers
Reinforcementslower cost/enhancemechanicalpropertieswood flour, kaolin,cotton, glass, carbon,micalow to high,depending onapplicationmainly used inrigid plastics
Pigmentsallows wide rangeof colorscarbon black, titaniumdioxide, lead compounds�1-4%polystyrene,polypropylene,PVC
FlameRetardantsslow the burningplastics/inhibitvolatilization ofcombustible gaseshalogenatedhydrocarbons, antimonyoxide, phosphorouscompounds, aluminatrihydrateDepends on typeof application,flammability ofresin, andpresence ofother additivesall types
Antioxidantsretard oxidativedegradationhindered phenolsthioesters,organophosphite0.05-1.0%polyolefins,styrenics
Blowing agentscreate foaming,softnesshydrazine derivatives,citric acid/sodiumbicarbonate, nitrogen, airdepends onqualities neededpolyurethane,PVC, styrenics,low density poly-ethylene
Lubricantsimproveprocessingfatty amides, PTFE wax,fatty acids, esters, waxes,metal stearatesdepends onplastic/processingtechniqueprimarily PVC,also polyolefins
Heat Stabilizersprotection fromthermaldegradationmixed metals salts,organotins leadcompoundsdepends onconditionsprimarily PVC
UV Stabilizersto avoid UVdegradationpigments and carbonblack, benzophenones,amine light stabilizers0.05-2%polyolefins andother plastics usedmainly outdoors
Impactmodifiers/Processing aidsimproveresistance tostressthermoplastic elastomersdepends onproduct usemainly PVC, alsopolyolefins
The types and amounts of additives used depend on the particular product and its use;therefore formulations of additives vary widely. For example, the use of several types ofadditives, such as flame retardants and blowing agents depends on the type of use for thetoy (e.g., a flame retardant might be used on a play tent but not a teether).In general, none of the alternatives requires the use of phthalate softeners and all containless total additives than PVC. When they do contain additives, these make up only a very
small percentage (0-2% each of the polymer mixture), compared to up to 50% phthalatecontent in PVC toys (without considering the many other additives PVC requires). [5]For example, ethylene vinyl acetate (EVA) plastics can contain additives (UV stabilizers,antioxidants and pigments). The alternatives also appear to have less leachables thanPVC, meaning that it is more likely that additives will be bound to the plastic polymer orretained by the polymer matrix. It is well known that the phthalates are not chemicallybound to PVC, so that they can easily leach out during normal use.Description of substitutes for PVC in toysThermoplastic elastomers: (TPE)TPE is a material that combines the processability of a thermoplastic with the functionalperformance and properties of a conventional thermoset rubber. This allows processingof flexible, rubbery articles with speed, efficiency and at low cost. These materials canmatch or better the characteristics of flexible PVC in terms of strength, appearance andperformance. The TPEs have the highest growth rate among materials at 8-9%, as newerapplications come up replacing conventional flexible materials, one of which is PVC.Many TPEs are on the market today, and are being widely used for applications wherePVC or rubber was used. Many of the TPEs are copolymers or alloys of conventionalplastics. A co-polymer is two or more different polymers chemically linked together,while an alloy or blend is a physical mixture of two or more polymers. Copolymers andpolymer blends allow tailoring of product qualities through variation in the quantity ofeach polymer involved.TPEs can be processed into a wide range of flexibilities, strength properties, and areeasily colored, and are easily processed with conventional equipment. They also havehigh temperature range without degradation and have good resistance to a wide variety ofenvironments. Finally, TPEs have a rich, tactile 'feel' adding to their aesthetic qualities.Two most important fabrication methods for TPEs are extrusion and injection molding.Both the equipment and methods normally used for the extrusion or injection molding ofa conventional thermoplastic are generally suitable. Materials such as olefinic TPEs canbe blow molded on standard equipment to produce figurines and hollow parts. They canalso be calendered like PVC for flexible sheet manufacture and post form heat-welded toproduce inflatable toys. These materials can also be thermoformed and foamed usingchemical and mechanical blowing agents. TPEs are currently used in the automotive,medical, food, construction, industrial, business machines and consumer applications.Most of the TPEs can be produced in a wide hardness range (from 30 Shore A up to 75Shore D) without the use of additives by controlling the hard matrix phase and softdomains interspersed in the hard matrix. This would greatly reduce the possibility of anyadditives leaching post-processing and use.
There are numerous TPEs available on the market. Some of the most applicable assubstitutes for PVC toys include:Styrenic block copolymers: These TPEs have a low cycle time, and can beprocessed by conventional molding techniques. The combination of styrenic TPEscan be controlled during manufacture to give a wide range of properties like strength,flexibility, tack, and softening temperatures. Styrenic TPEs offer high surface quality,durability, and lack of crumbling. Styrenic TPEs include styrene/butadiene/styrene(SBS) block copolymers, styrene/isoprene/styrene block copolymers, styrene/ethylene-butylene/ styrene (SEBS) block copolymers, and styrene/ethylene-propylene/styrene block copolymers. SEBS is already used in the production of toys(teething rings by Tolico in Denmark) and can replace PVC for the production ofdolls heads (with hair) using rotational molding techniques, one of the most difficultPVC substitutions.Polyolefin blends: Olefinic TPEs are blends of olefinic thermoplastics (mainlypolypropylene) and elastomers, also generally olefinic. These also can be controlledto give a wide range of properties ranging from flexible elastomeric to tough, rigidmaterials, for use in a range of applications. These TPEs have excellent weatheringproperties and resistance to environmental conditions and chemicals. They also haveeasy coloring characteristics.Elastomeric alloys: This category of TPEs (also known as synthetic rubber) cansuccessfully replace rubber because of its processing ease as compared to rubbers. Anexample of an elastomeric alloy is a mixture of polypropylene-ethylene-propylene-diene-terpolymer (PP-EPDM). These TPEs can be processed with conventionalmachinery capable of heat and shear melting of materials, similar to those used forpolypropylene, polyethylene and PVC.Given the various types of TPEs on the market, custom compounding is conducted forTPE materials to suit wide performance capabilities from flexible films to rigidapplications. A more extensive analysis of TPEs is justified to better understand thecharacteristics of various TPE grades and types that could replace different PVCapplications. One type of TPE, thermoplastic polyurethane, uses significant quantities ofchlorine, and therefore would not be considered a suitable substitute for PVC. TPEpolymers that appear lower on the pyramid of plastics such as polyolefins, are preferableto those higher up the pyramid, such as styrenes.Commercial informationTPEs are produced by companies such as DuPont, Monsanto, Eastman Chemicals, Shell,Hoechst Celanese, GE Plastics, Himont, Exxon, Mytex, CFT and various companies likeM. A. Hanna, Tecknor Apex, which can custom compound the material according tospecific performance requirements.
Ethylene vinyl acetate: (EVA)Like PVC, EVA can range from thermoplastic to elastomeric state, depending upon thevinyl acetate (VA) content of the copolymer. [6] Vinyl acetate is produced by one ofthree methods: by reacting acetylene and acetic acid; by passing mixed vapors (acetylenegas with acetic acid vapor) over a catalyst of zinc acetate; or by reacting ethylene withacetic acid and oxygen in the presence a catalyst.EVA is made by the co-polymerization of ethylene and VA by free radicalpolymerization initiated either by a peroxide or perester. With the increase in VA content(5-50%), the molecular crystallinity is reduced and material properties are affected.Properties like clarity, low temperature flexibility, heat sealability, and impact strengthimprove with increased VA content, without the use of leachable plasticizers or otheradditives. These properties are retained over time unlike plasticized PVC, which wouldlose its plasticizer and other additives and become hard, especially when exposed to harshSome polyethylene/EVA copolymers has been shown to contain additives, includingphthalates, which could be present deliberately or as a result of contamination in theprocess technology. However, EVA does not require phthalate additives to achieveflexibility and direct use of phthalates or contamination sources should be eliminated,along with other toxic additives, if EVA is to be a viable PVC substitute.Sealing temperatures are reduced with EVA, leading to a reduction in the fabrication timefor flexible sheets and films, increased efficiency and lower production cost. EVAcopolymers can accept high degrees of filler loading without serious degradation of theirphysical properties.EVA can be used in toy manufacture to achieve a broad range of toy properties including:flexibility, toughness and resilience. EVA has a good stress cracking resistance for toyswhich would require periodic washing and cleaning with chemical or physical agents.EVA processing techniques are similar to those used with low-density polyethylene. Itcan be processed on standard processing equipment by major plastics processingtechniques such as injection molding and virtually all extrusion processes (such as sheetextrusion). Because EVA is more polar than polyolefins, it can also be radio frequencywelded for flexible sheeting and film applications. However, due to high surface tackand friction, processing EVA films may require special attention (such as anti-statics oranti-blocking agents). Tack refers to the stickiness that EVA possesses, which may causethe plastic melt to stick to the metal walls of the processing equipment.There is a large market for EVA, particularly for flexible film and sheeting, which ismainly used in packaging. It is currently available in the market in the form of films(60%), extruded forms (6%), and color coatings (can be very important for toys),injection and blow molded applications (5%). Some toy manufacturers such as BabyVision, Early Start, Learning Curve, and International Playthings are already using EVA
in the production of teething rings and other soft infant toys. Because of its ability to beheat and radio frequency welded, EVA could also be an excellent candidate to replacePVC in inflatable toys. EVA could also be used in rotational molding to produce dollsheads and other parts.A multitude of other types of vinyl acetate co-polymers are available, many of thembeing used in packaging and coating applications. Also, by increasing the VA content ofthe co-polymer (over 40%-50%), additional ethylene-vinyl acetate copolymers areformed. These have either thermoplastic properties, elastomeric properties, or thermoset(vulcanized rubber) properties. Vinyl acetate-ethylene elastomers have a widecolorability, color retention, and good age stability.Lastly, polyvinyl alcohol (PVOH) is commonly produced through the transformation ofEVA. PVOH is a water soluble material with wide application in the adhesive area.Commercial information:EVA is produced by DuPont Co., Exxon Chemicals, Union Carbide Corp., QuantumChemicals, Bayer Corp., Chevron Chemicals, Elf Atochem and MilleniumPetrochemicals Inc.PolyolefinsPolyolefins have been used for decades in the toy industry and are a preferred plastic formany applications because of their ease of processing by injection, blow and extrusionmolding; their durability, colorability, and cost-effectiveness. Polyolefins are extremelyversatile, with differing properties being achieved without the use of plasticizers or otheradditives. For example, the polyethylenes can be made from hard to soft by modifyinghydrocarbon chain length or cross-linking. In general, increasing the density of thepolyolefins increases stiffness, hardness, heat and chemical resistance, but reduces impactstrength and stress-crack resistance. Polyolefins are also popular due to their low energydemand during melt processing. Polyolefins can be considered among the leastdangerous petrochemical plastics in terms of their environmental impacts throughInstead of developing new thermoplastic materials, companies are more and moreconcentrating their efforts on the development of new blends of polyolefins and otherexisting polymers, which can be tailored to suit various applications and performancecharacteristics. A large variety of polyolefins are can be used directly or blended withother materials to suit particular needs. Some of these polyolefins surpass PVC instrength, clarity, flexibility and other related properties.Examples of some polyolefin replacements are provided in the following paragraphs.Companies such as Mattel are already producing soft children's toys, such as soft blocks,out of polyethylene.
Polyethylene: Very low density polyethylene (VLDPE) can also be used as a PVCreplacement, as it has better environmental stress cracking resistance, improvedtoughness, a higher softening temperature, and good low temperature impactproperties. VLDPE does not have any volatiles or extractable plasticizers, nor the tackassociated with EVA. Linear low density polyethylene (LLDPE) offers goodstiffness and impact strength/toughness, excellent environmental stress crack andwarp resistance. Ultra-low density polyethylene (ULDPE) is an ethylene copolymerwith excellent environmental stress crack resistance, outstanding flex-life and flex-crack resistance, toughness and good sealability.Polypropylene: Polypropylene offers similar properties as polyethylene includinglow density, good mechanical, temperature, flexing/fatigue, and stress crackresistance and rigidity. It also has excellent colorability and is easily pigmented.Polypropylene is often manufactured as a copolymer to impart differentcharacteristics, such as flexibility and rubbery texture.New developments in polyolefin technologyAdvancements in catalyst research has led to the development of metallocene polyolefins.The metallocene catalysts allow greater process control, stereospecific molecularstructures and a narrow molecular weight distribution in the polymer main chain,maximizing the uniformity of polymer physical properties. Because of this narrowmolecular weight distribution, there are few low molecular weight chains, leading to lowextractables and leachates. In essence, the metallocene catalysts allow the precise andpredictable tailoring of process chains to impart a range of qualities on the polymer, withminimal use of additives. This technology is also being applied to polyolefin alloys suchas EPDM.Metallocenes have a good ability to incorporate different comonomers, including higheralpha olefins, such as octene into the polymer. When ethylene is co-polymerized with upto 20% of higher a-olefins, new materials called plastomers are produced. Plastomers areflexible and thermoplastic and have better properties than conventional polyolefins, atmuch lower densities. Copolymers containing more than 20% of comonomer are calledpolyolefin elastomers. These polyolefin elastomers have better flexibility, clarity, andtensile strength. This would allow them to replace PVC in applications such as inflatabletoys with better mechanical properties and a thinner and lighter film, reducing the amountof material and waste generated.Syndiotactic Polypropylene (sPP), meaning that the polymer molecules are arranged in ahighly regular manner, has flexibility, clarity, and tensile strength as well as low heat sealtemperatures, enabling it to be used in place of materials such as PVC, EVA, and linearlow density polyethylene (LLDPE) in films, foil for decoration or stickers, and toys thatneed to be extruded.Metallocene products have a significant advantage over PVC in that their low densityallows as much as a 40% reduction in weight per part. They have a lower melt
processing temperature and much lower injection molding cycle times (25% less) thanPVC. The resins are also more thermally stable than PVC. It has been estimated that thesavings for metallocene products in terms of cost per part over PVC are in the range of25-30%. [7]Metallocene polyolefins can be processed using conventional techniques such as injectionmolding and in some instances products can be produced on the same equipment as PVC.Due to their wide range of properties and process control, the metallocene polyolefins areexpected to take over a large percentage of the flexible PVC market in the coming years.Nonetheless, while these polyolefins are currently being produced by severalmanufacturers, wide-scale production capacity could take time to develop.Developments in polymerization techniques also allows the production of various alloysand blends in the reactor itself. A series of polymerization reactors facilitates theproduction of blends. A combination of various polyolefins with an ethylene-propyleneelastomer (which introduces flexibility into the blend) allows the synthesis of a broadrange of materials having medium to very high strength, particularly impact strength,since a soft, rubbery phase is introduced in a base polymer. Blending of these specialreactor blends with LLDPE produces a material that can be used to replace PVC in mostflexible applications.Emerging technology in polyolefin production provides greater control over molecularstructure and composition, as well as polymerization and blending, resulting in materialswith a broad range of characteristics that can replace virtually all soft PVC use in toys.Commercial Information:Polyolefins are produced by numerous companies throughout the world. Dow Chemicals(Plastics group), Exxon Chemicals, Huntsman Corporation are initiating commodityproduction of metallocene polyolefins. [8]5 see Ruth Stringer, I. Labounskaia, D. Santillo, P. Johnston, J. Siddorn and A. Stephenson, Determinationof the Composition and Quantity of Phthalate Ester Additives in PVC Children's Toys, GreenpeaceResearch Laboratories Technical Note 06/97, September 1997 and Joseph Di Gangi, PhD, Warning:Children at Risk, Toxic Chemicals Found in Vinyl Children's Products, Greenpeace USA, November,1998 and Greenpeace China, Greenpeace Study on Hazardous Additives in PVC Toys Sold in HongKong, October, 1998, Testing by the Hong Kong Standards and Testing Centre Ltd.6 Though vinyl acetate is also a "vinyl", this refers to the chemical structure of the monomer and not to thepresence of chlorine, which makes PVC a problem plastic.7 Robert Wilson, Jr. The Impact of Metallocenes on PVC. SRI International, 1997, presented at the WorldVinyl Forum, Akron, OH.8 See David Rothman, Metallocene Polyolefins, in Chemical Week, May 21, 1997 for an overview ofmetallocene production capacity and benefits.
Section 6: Lifecycle Considerations for AlternativeIn addition to considering the health hazards of plastic toys during use, manufacturersneed to consider the impacts of their choice of material throughout the product lifecycle.It is important that manufacturers take responsibility for the environmental and healthimpacts caused by the production and disposal of the materials they use, constantlyattempting to identify alternatives that reduce those impacts. Key environmental issuesthat need to be considered in material selection include:Production: toxic emissions from production, potentially exposing workers, surroundingcommunities, and distant communities. Emissions from subsidiary manufacture(compounding, product production) and associated manufacture (additives) must also beconsidered.: exposure to additives during product use, toxic chemicals generated in accidentalfires.: by-product creation during combustion, impacts in landfills, recyclability. Mostplastic recycling is not true recycling (producing the same product) but ratherdowncycling (producing different, lower grade products). Bio-based plastics offer thebest opportunity for recyclability and are preferred to any petroleum-based plastic.There are clearly some plastics that are better from an environmental standpoint thanothers. See Appendix B for information on the environmental impacts of variousplastics, which are ranked in a pyramid, from worst to best, with PVC as the worst.
Section 7: Cost Analysis of AlternativesThe cost of a toy or any article can be broken into direct and indirect costs. The directcosts are raw material costs, processing, labor, equipment and associated costs. Theindirect costs (often called external costs) which are difficult to calculate, can be greaterthan direct costs, and are often incurred by workers, communities, and consumers. Theseinclude: environmental impacts, impacts to health, hazardous material handling costs,waste disposal, damage to production or recycling equipment, and costs associated withproduct replacement (when products are not durable).Costs which should be considered when examining alternative materials include:Superior material properties of the alternative over PVC.The extremely rapid processing of alternative materials using conventional and theThe amount of waste and scrap generation in the process and the reprocessability ofthat waste.Alternative materials may have simpler processing operations and conditions,including shorter downtimes and more economical purging requirements.Increased life of the expensive equipment and tooling due to lack of corrosivehydrochloric acid gas emitted during the processing of PVC. All molds, screws,barrel walls, and parts coming in contact in direct contact with PVC melt must bechrome plated to avoid corrosion, which is an expensive process.Alternative materials can be used for producing thinner parts which can match orbetter PVC's performance. This reduces the cost per unit area by lessening productweight. For example, due to their improved strength qualities, thinner metallocenepolyolefin films can be used in applications where PVC films were conventionallyused. This offsets the additional cost of metallocene polyolefins.Advances in technology such as thin wall injection molding can also help offset theexpensive rotational molding cost by producing thinner, lighter, and stronger toys.Thinner, less bulky toys can save on transportation and shipping costs and reducesmaterial use.Despite the cost justification factors listed above, given that a conventional toyweighs only a few hundred grams, final product costs would only vary slightly formost of the alternatives listed in this report. This assumes that product weight staysthe same, which may not be the case for new polyolefin production techniques.A per pound price list for various plastic materials is listed below. Several of thealternative materials listed in this report are currently cost-competitive with PVC.However, since parts are usually made by volume and not weight, a simple comparison ofthe price per unit weight (e.g. U.S. dollars/lb) would be misleading. Figures ofcomparative volume cost are an important issue to consider. It may also be the case thatwith two alternative materials, the one with a higher volume cost may prove to be moreeconomical. One reason for this may be that the more expensive material is stiffer andcan thus be used in thinner section moldings.
Table 3: Costs of PVC and various alternative materialsMaterialCost per pound (US dollars)
PVC0.35-0.70 depending on the grade
Polyethylenes0.40-0.55 depending on the grade0.55-0.60 metallocene products
EVA0.50-0.80 depending on grade, VA content
Polypropylene0.30-0.50 depending on the grade
Section 8: ConclusionsThe debate over the hazards of PVC toys must move away from a discussion about risk,which is almost impossible to calculate and will vary from individual to individual, toone based on the availability of safer alternatives. This report has described threealternative types of plastics that can replace PVC in all of its toy applications (there aremany other plastic and non-plastic materials that could replace PVC applications). Whilemost of these alternatives represent drop-in substitutes with minimal processing changerequired, some PVC applications, such as dolls heads, may require research anddevelopment prior to their effective replacement. In general, alternatives are cost-effective, often more easily processed, offer better physical qualities (increasing toysafety), avoid the use of phthalate plasticizers and use minimal additives, and havereduced environmental and health impacts throughout their lifecycle. It should beensured that any additives are minimal and non-toxic.Materials such as the metallocene polyolefins, thermoplastic elastomers, EVA and otherolefin blends can be considered the best currently available plastic alternatives from asafety and lifecycle perspective for replacing soft PVC applications today. Newtechnologies can also play an important role in justifying PVC replacement with thesematerials. Designers are pushing the limits of thin wall injection moldings usingpolyolefins, reducing material use in toy production. New processing techniques such asgas assisted injection molding can be used to produce toys which appear bulky from theoutside but which are actually hollow on the inside. These advancements, particularly inpolyolefin technologies, will lead to alternatives with superior polymer strength (allowingthinner polymers to be produced) and variability in characteristics using minimalamounts of additives, while reducing waste generation and materials use. Advancementsin biodegradable plastics also hold hope for the future production of toys that are moresustainable through their lifecycle.
Table 4: A summary of PVC alternatives for ToysPlasticFlexibilityProcesstechniquesReplacementtypesCost/lb.(in dollars)Environmental
Thermoplasticelastomers:Styrenic,Polyolefin,Alloys, TPUswide,depends onco-polymeror blend typeand amountsblow molding,extrusion,calendering,rotationalmolding,thermoformingteethers, dollparts/figures,squeeze toys,possiblyinflatable toys0.85-1.87depending ontype andblend or co-polymermixtureChemicals used:styrene andpolyurethaneproduction arehazardous and bothoff-gas toxicchemicals in fires
EVAwide,depends onVA contentof polymersheetextrusion,injectionmolding,rotationalmoldinginflatable toys,teethers,possibly dollparts0.50-0.80chloride catalystused in some vinylproduction; byproducts fromethyleneproduction
Polyethylenes,Polypropylene,blends/alloys,metallocenecatalyzedpolyolefinswide,depends onchain length,co-polymeror blendall majorprocessingtechniquesall currentPVC toyapplications0.40-0.550.55-0.60metalloceneproductsby-products fromethyleneproduction
No plastics expert will dispute the fact that PVC toys contain large amounts of phthalateplasticizers and that these additives to some degree leach. They will also not dispute thefact that other plastics do not require the large amount of additives required by PVC.Scientists agree the phthalates do have demonstrated toxic effects in laboratoryexperiments and that that little is known about how toxic chemicals in any amount canaffect the developing child.In the meantime, the current debate in the EU and the US focuses on whether "safe"levels of phthalate exposure can be found. Instead, policymakers should acknowledgethe legitimate debate on the hazards of phthalates and the near impossibility of estimatingrisk of harm to children and prioritize the health of small children over the likely minimalcosts to a multi-billion dollar industry of using substitute materials.In the end, given the mounting evidence of the potential hazards that PVC toys pose tochildren, and the wide availability of cost-effective, safer alternatives, there appears to beno compelling reason for the toy industry to continue using PVC in its productionprocesses. With the large amount of additives required for PVC, and its lifecyclehazards, switching from one additive to another (which may create new risks) is anunacceptable solution.Government agencies entrusted with protecting children's health should require thesubstitution of PVC as the only measure which will adequately protect children's healthfrom the hazards of PVC.
Appendix A - Plastics additives used in toysBelow is a short description of some of the main additives used in plastic toys.Antioxidants: Virtually all plastic materials undergo reaction with oxygen. Oxidationinduces breaking of long chain plastic molecules, which are responsible for its properties,into smaller low molecular weight entities. This causes a loss in plastic qualities.Addition of antioxidants, retards oxidation and thus the aging of the polymer.Antioxidants are usually used in a concentration of a fraction of one percent so leachingis very limited. Commonly used primary antioxidants are phenols and amines,phosphites, and sulfur containing compounds.Lubricants: In polyolefin processing, lubricants are used to reduce friction between themetallic walls of a screw and barrel by forming a release film. When the lubricant is usedto reduce processing difficulties, it can be classified as an internal or external lubricant.An external lubricant is on the surface of the polymer while an internal lubricant issoluble in the polymer molecules.Stabilizers: These are primarily used in PVC processing, to allow processing and use ofrigid PVC at elevated temperatures without degradation. Stabilizers retard aging anddegradation by preventing the formation of hydrochloric acid gas (dehydrochlorination),avoiding oxidative degradation. Sometimes, in PVC formulations, costabilizers are used.Costabilizers do not possess thermostability ability as such, but improve the effectivenessof stabilizer systems. For example esters of phosphorus acid, epoxy compounds, polyols,and phenolic antioxidants are used as costabilizers.UV Stabilizers: Light and oxygen may induce degradation (photo or oxidativedegradation) reactions in plastics that may change the clarity and lower the physicalstrength of the material. Light stabilizers and UV stabilizers are used to retard thisdegradation. Light stabilizers are chemical compounds capable of interfering with thechemical and physical process of light induced degradation.Fillers/Reinforcing Agents: Inorganic materials are frequently used to reduce cost,increase low cost bulk and/or improve some specific material property. When propertyenhancement is done, a filler is also referred to as a reinforcing filler. Since fillers areeither chemically bound to the molecule, or embedded in the polymer matrix, there maybe a low incidence of leaching on the surface by molecular movements.Colorants: For aesthetic purposes, toys make extensive use of colorants. These areclassified as pigments, which are virtually insoluble in plastics and dyes, which aresoluble. Pigments are normally melt mixed with the plastic and are known as dispersioncolorants, while dyes are dissolved in the plastic and are present in a molecular solution.The colorants have to be thermally stable and resistant to weathering and must not fadeout with time. However, migration of colorants as a result of partial solubility in a plasticmay be seen as a problem.
Flame-retardants: Flame retardants are used to fulfill flame retardancy requirementslaid down in regulations and for safety reasons. This is accomplished by inhibiting orsuppressing the combustion process. Flame retardants used as additives, can eitherchemically or physically lower the combustibility of plastic materials. Flame retardantsimpede and stop the propagation at any stage of combustion.Blowing agents: These are chemical agents which produce gases through reactions andhelp in the manufacture of foams. Azo compounds, which give off nitrogen gas, arewidely used as blowing agents.Processing aids: These are high polymeric materials added in small quantities tothermoplastic resins that are difficult to process. Processing aids help to accelerate themelting process, and improve the flow properties of the plastic material duringprocessing. These also contribute towards improving the mechanical properties, unlikesimple additives like plasticizers.Appendix B: The Hierarchy of Plastics
The Greenpeace Plastics Pyramid of ProblemsThe following is an attempt to "rank" the most common plastics. Environmental andhuman health problems related to production, additives, product emissions, disposal andfires are considered. The aim is to provide a basis for choosing and developingalternatives for PVC. The list is ranked from the worst to the best.
Polyvinyl Chloride (PVC) - PVC has been identified as the worst plastic from alifecycle perspective because of the creation of dioxin and other persistentorganochlorines during its production, use, and disposal; hazards posed by its cancer-causing monomer, vinyl chloride; its lack of recyclability; [9] and its heavy use ofdangerous additives such as lead, cadmium and the phthalate esters which can leach outduring use. [10] These lifecycle hazards have led to several European nations, localgovernments, manufacturers, scientific and public health organizations to scrutinizeand/or pass restrictions on PVC use.Polyurethane (PU) - PU production and its intermediate products consume about11% of worldwide chlorine production. Polyurethane production uses several veryhazardous intermediates and creates numerous hazardous by-products. PU productionhas been linked to numerous occupational health problems including heart disease,asthma, and reduced sperm quality. Toluene diisocyanate, used in PU production, is astrong respiratory sensitizer. The burning of PU releases numerous hazardous chemicalsincluding isocyanates and hydrogen cyanide. PU is potentially more hazardous in thework environment than PVC and is thus likely not an acceptable alternative, withoutsubstantial process change to reduce exposures and chlorine use.2 B. Polystyrene (PS) - PS is made from benzene and ethylene raw materials. It iswidely used for foamed insulation and also for hard applications (e.g., cups, some toys).Polymerized with other materials, it becomes a thermoplastic elastomer (styrene-ethylene-butylene-styrene). Other materials used in its production include butadiene andethyl benzene. Benzene is a known human carcinogen. Butadiene and styrene (the basicbuilding block of the plastic) are suspect carcinogens. Styrenics generally require farfewer additives than PVC and are inert in final form. However, though the lifecycle ofPS appears to have less impacts that that of PVC, styrenics may not be an adequate long-term substitute for PVC for several reasons: the hazards of its raw materials, which areespecially dangerous to workers; fire hazards; high energy consumption; the need forCFCs for foaming; and poor recycling.Acrylonitrile-butadiene-styrene (ABS) - ABS is used as a hard plastic in manyapplications like pipes, car bumpers and toys (hard building blocks). ABS uses a numberof hazardous chemicals. These include butadiene, styrene and acrylonitrile. Acrylonitrileis highly toxic and readily absorbed by humans by inhalation and directly through theskin. It is classified as a probable human carcinogen as are styrene and butadiene.Additives used include antioxidants and light stabilizers. ABS is extremely difficult torecycle, similar to PVC.Polycarbonate (PC) - PC is used for products like CDs and refillable milk bottlesand is usually made using the highly toxic phosgene derived from chlorine gas. PC doesnot need additives but does need solvents for its production, such as methylene chloride,a carcinogen. A number of processes have been developed to reclaim polycarbonatefrom CDs, milk and water bottles, but only for downcycling into lower quality products.
Polyethylene-terephthalate (PET) - PET is made from ethylene glycol anddimethyl terephthalate. PET is generally used in packaging and often contain additivessuch as UV stabilizers and flame retardants. In production, PET uses a number ofsubstances irritating to the eyes and respiratory tract. PET recycling rates are highcompared to other plastics.Polyolefins4 A. and B. Polyethylene and polypropylene (PE and PP) - PE and PP belong to thepolyolefin family, as do metallocenes, and are completely petroleum based. It isimportant to note, however, that polypropylene is often made using a chlorineintermediate process though a viable non-chlorine alternative exists. The raw materialsused in these plastics are relatively harmless, but can be flammable or explosive. Also,the cracking of hydrocarbon feedstocks generates persistent organic substances, such aspolyaromatic hydrocarbons (PAHs). Petroleum production also generates dioxins due tothe use of chlorine catalysts. Finally, the burning of these plastics can generate manyvolatile compounds, including formaldehyde and acetaldehyde, both identified asprobable carcinogens.Despite hazards from polyolefin production, these can be considered the least harmful ofBiodegradable and bio-based plastics - Polyolefin plastics can be madebiodegradable by creating weak links in the polymer chain so that bacteria and othermicroorganisms can break it down. While this is an important first step towards moreenvironmentally friendly plastics, biodegradable, petroleum-based plastics cannot beconsidered an environmentally safe, sustainable replacements for PVC in the long run.The future lies in what are called bio-based plastics.Bio-based plastics are created from plant materials (starch, cellulose), lactic acid, orbacteria (bacteria are fed sugars and create the polymer as a waste product). Majorcorporations including ICI, Monsanto, and Cargill are currently making these plastics. Itis essential that the production of bio-based plastics does not involve the use and releaseof genetically modified organisms or allow the patenting of life.They are currently used in packaging applications and researchers are working on bio-based plastics for medical uses. Weaknesses of bio-based plastics are: cost andproduction size (economies of scale have not been achieved); material properties (theycan be used only for relatively short lived products right now); and a lack of compostinginfrastructure for their disposal.9 PVC Plastic: A Looming Waste Crisis, Greenpeace International, 1998.10 See Danish Environmental Protection Agency, PVC and Alternative Materials, 1993 and DanishTechnical Institute, Environmental aspects of PVC, 1995 for a detailed overview of PVC lifecyclehazards.

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