Automotive Recycling - ACS Publications - American Chemical Society

Chapter 4

Automotive Recycling

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R. A. Pett, A. Golovoy, and S. S. Labana Ford Motor Company, P.O. Box 2053, MD 3198 SRL, Dearborn, MI 48121-2053

The technology of vehicle recycling today is capable of recovering and reusing about 75% of the weight of scrap vehicles. The 75% recycling rate is believed to be the highest recycling rate in durable goods. Moreover, with a technology that was developed in the '70s, vehicle recycling is a profitable undertaking and, consequently, a robust infra-structure for handling and recycling scrap cars exists today. The recovery of materials from scrap vehicles, however, is generally limited to metals, such as steel, iron, zinc, aluminum, and copper. Non-metallic materials are usually discarded to landfills. The technology of recycling plastics and other non-metallic materials, including fluids, from vehicles is at its infancy and its profitability in many cases is yet to be determined. Several trends are developing in the automotive industry which will have a positive effect on recycling. Examples are the recent applications of recycled plastics, elastomers and fluids, the marking of plastic parts, and the joint R&D recycling projects between the automotive companies, suppliers, and recyclers. Recycling and proper disposal of materials are growing concerns throughout the industrial world. In the last decade in particular, a number of laws have been enacted to encourage the collection and recycling of food packaging and consumer goods materials. Of increasing concern has been the recycling and safe disposal of materials from durable goods. The automotive industry, because of its size, appears to be the focus of keen attention and may eventually become a target for environmental action. Recycling of scrap vehicles is not new. In fact, in North America an elaborate infra-structure exists which successfully collects scrap vehicles, recovers useful components, and recycles ferrous and non-ferrous metals. These activities enable 0097-6156/95/0609-0047$12.00/0 © 1995 American Chemical Society In Plastics, Rubber, and Paper Recycling; Rader, C., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1995.

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PLASTICS, RUBBER, AND PAPER RECYCLING

the recovery and recycling of about 75% of the weight of a vehicle. It is important to note that the vehicle recycling business is quite profitable in the U.S.A.


Today, the non-metallic materials are land filled. In the last 5 years, the automotive industry and its suppliers have initiated many efforts to address the recycling issues of automotive plastics, elastomers, and other non-metallic materials. This chapter reviews the existing infra-structure for vehicle recycling, recent technological and commercial developments in recycling thermoplastics and elastomers, and future trends. Infra-Structure of Scrap Vehicles Recycling Broadly speaking, vehicle recycling consists of two sequential operations: vehicle dismantling and vehicle shredding. The industry for recycling scrap vehicles is very well developed in the U.S. and elsewhere. It consists of salvage dealers (wreckers and junkyards; about 15% in North America are members of the Automotive Recyclers Association - ARA), and shredder and secondary metal recovery operators (most are members of the Institute of Scrap Recycling Industries - ISRI). There are approximately 12,000 salvage dealers and 190 shredders in the U.S. salvaging and recycling about 10 million vehicles annually. Salvage Dealers. Salvage dealers gather and store scrapped vehicles and are responsible for de-registration paperwork. They remove parts which have reasonable market value or are not accepted by the shredder operators. They supply many used replacement parts, in competition with the new replacement parts, to collision and repair shops. Some salvage dealers maintain warehouses which rival in sophistication OEM's parts distribution centers. Components which have recycling value and are handled by the salvage dealer include engines, transmission, body panels, catalytic converters, batteries, radiators, and so on. In fact, any component which can be sold or reconstituted is salvaged. The salvage dealers also drain auto fluids, such as engine oil, engine coolant, brake fluids, and transmission fluids. Many salvage dealers now ship the drained fluids to reclamation companies or use the fluids as fuel. Collection of Freon (R-12) is required by law. Examples of reclaimed/recycled components: Batteries. Dead automotive batteries are collected at the point of sale of new batteries. A number of states have deposit laws or otherwise require the battery sales outlets to collect old batteries. Lead, acid, and plastic (from the case) are all recovered and recycled. Ford Motor Company is using large quantities of polypropylene recycled from battery casings in some of its cars. Catalytic Converters. Precious metals can be recovered from discarded catalytic converters at a profit. Hence, the infrastructure for recovery and recycling

In Plastics, Rubber, and Paper Recycling; Rader, C., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1995.

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of precious metals from catalytic converters has developed rapidly. Converters are removed at the salvage yard and sold to precious metal processors.


Shredders do not accept tires, fuel tanks, and undeployed air bags. Fuel tanks are removed, and steel tanks are crushed and sold separately for metal recovery. Air bags are of significant concern to salvage dealers and the automotive industry. Procedures for the proper deployment of undamaged air bags have been developed by SAE and AAMA. Automobile Shredders. All major automobile producing countries have more than adequate capacity to shred the supply of scrap automobiles. Shredders receive either whole or baled vehicle bodies from the salvage yards. Shredder capacity ranges from 200 to 1500 cars per day. Some shredders accept cars with engine blocks, and others will accept car bodies only with engine blocks removed. The car body is passed through a hammer mill and shredded into fist size fragments. The output is separated into magnetic fraction (ferrous metals) and non-magnetic fractions. The non-magnetic fraction is separated further, by density using water or air, into metallic fraction (zinc, copper, aluminum) and lighter non-metallic materials. More recently a separation process based on magnetic susceptibility of non-ferrous metals has come into use. The remaining lighter fraction is called automotive shredder residue (ASR) or fluff. Some shredders wash the lighter fraction to separate sand, soil, and ground glass from the rest of the light materials. Shredders make their profit from the recovery of metals from scrap cars. Approximately 11 million tons of steel are recovered annually in the United States from scrap cars. Other metals which contribute significantly to shredder profits are aluminum, copper, zinc, and stainless steel. Not all shredders process non-magnetic metal fraction. These shredders sell this fraction to other processors who recover these metals. A shredder generates 500 to 800 pounds of ASR (fluff) per car, composed of about 27% plastics (Table I) (i). The rest is ground up glass, sealers, sound deadeners, Table I:

Auto Shredder Residue Average Composition Plastics Fluids

27%

Glass

16%

Textiles Rubber Other

17% 12% 7% 21%

dirt, sand, fabric, adhesives, paint, fabric, rubber, and metal pieces attached to nonmetallic materials. ASR has a heating value of 4800 to 6800 BTU's per pound, depending on the amount of glass, metal, water and dirt in it.


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It is important to appreciate that what brought about the development of the vehicle recycling infra-structure is the profit opportunity. But the profit margin may be decreasing in the future. In the last 10 years, the number of landfill sites has been decreasing and the tipping fees escalating in some regions. A second possible reason for the decrease in profitability is the increasing use of lighter materials such as plastics and composites in newer vehicles. The overall increase in plastic will inscrease the amount of ASR per vehicle and the fraction of plastics in ASR is likely to increase in the future. These changes may decrease the profit margins of the automotive recycling industry. One way to maintain profitability is to reduce the amount of ASR that goes to a landfill site. This applies to existing vehicles as well as future models. The major attempt will probably be to recycle plastics, rubber, and glass which are the major constituents of ASR. In addition to recycling, incineration and pyrolysis will probably play an important role. To summarize the state-of-the-art in vehicle recycling: dismantlers and shredder operators recover and recycle parts and materials from scrap vehicles profitably. TTius, about 75% by weight of a typical vehicle is recycled today. Considering the complexity of auto design, a recycling rate of 75% is quite impressive. In fact, in the category of durable goods, vehicles have the highest rate of recycling. ASR and Solid Waste in U.S.A. In 1992, the amount of municipal solid waste (MSW) generated in the United States was approximately 195 million tons. Out of the total MSW generated each year in the U.S., 80% is disposed of in landfills, 10% is incinerated, and 10% is recycled. To save shipping costs, most landfills are located close to population centers. A typical landfill site is designed with enough capacity to last 10-15 years. Many landfills are getting filled to capacity, and in recent years the rate of opening new landfill sites has been much less than the rate of closing landfills. For example, in 1979 there were 18,500 landfills in the U.S. In 1989, there were only 6,000, and the number is expected to decline to 4,000 by the year 1995. The situation is already severe in the Northeastern United States where tipping fees have reached $120 per ton. For that reason, some shredders are now shipping shredder waste residue from the northeast to other parts of the country. Plastics in the solid waste are of special interest to us since most do not, or are slow, to degrade. Because of this, plastics have been the target of increasing negative publicity and the manufacturers need to take appropriate action to deal with plastic waste. Most of the plastic waste which is disposed of in landfills is from packaging and non-durable consumer goods. It is estimated that this source of plastic waste is about six times that from automotive waste. The total plastic waste in 1992 was estimated at 15 million tons. Actually, this is a small fraction of the total solid waste, accounting for about 7.5% by weight. On a volume basis, however, the fraction of plastics, after compacting in landfills, is about 20%. In an uncompacted state, the volume fraction of plastic waste would be about one third.


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The rate of growth of plastics, of the order of 5% per year, is higher than the growth rate of other materials. Plastics production in the USA during 1989 was of the order of 30 million tons; so there is considerable potential for an increase in plastics waste, which is estimated to reach 11% by weight, or 30% by volume, of the total solid waste in the year 2000.


As said earlier, only 10% of the solid waste is recycled. Specific examples of disposal and recycling data of principal materials in the United States are shown in Table II. You may note that the recycling of plastics and rubber is below 5%. Table II:

Materials Recycling Comparison

Material Aluminum Paper & Paper Board Glass Rubber & Leather Iron & Steel Plastics AUTOMOBILES

Recycling Rate. %

30 40 7 3 37 1 75

Even in the case of aluminum and paper products, which are considered as the most recycled materials, the recycling is less than 30%. By comparison, the recovery and recycling of components and materials from scrapped automobiles, amounts to about 75%. With this information in mind, let us look at the magnitude of automotive recycling. In a typical year, about nine million vehicles are shredded in the U.S. This operation generates 11.2 million tons of steel and 0.8 million tons of non-ferrous metals, most of which is recovered profitably. In addition, about 3.5 million tons of shredder residue is produced. At the present time, this residue is disposed of in landfills. Thus, the automotive shredder residue is of the order of 1.3% of the total municipal solid waste generated annually in the U.S. With the technology available today, a sensible approach to deal with ASR seems to be energy recovery via incineration which would reduce ASR weight by 50% and its volume by about 80%. This approach was demonstrated at the SEMASS Project, a waste-to-energy facility located in Rochester, Massachusetts. Along with municipal solid waste (MSW), the facility routinely mixes 2.5% of ASR with incoming MSW. Rigorous monitoring of stack emissions and ash composition has indicated no apparent increase in environmental impact by adding ASR to MSW. In particular, no increase in dioxins has been observed. A similar incineration test, conducted by The European Association of Plastics Manufacturers in a municipal waste incinerator in Wurzburg, Germany, showed a decrease in furans and dioxins, when up to 15% of plastic waste was added to MSW. Even when extra PVC was deliberately added to the waste, the level of


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dioxins produced during incineration was well below the German limit, which is the strictest in Europe. In spite of these demonstrations, it is not likely that incineration of ASR will play a significant role in the USA in the foreseeable future due to negative cost benefits. Elastomers Recycling Technologies Automotive Use of Elastomers. In a trend which has continued since the early 1980s, about 4 A % of the weight of a typical U.S. car is rubber. Approximately 134 pounds of elastomers (2) are used on the typical North American automobile (Figure 1). Of this amount, about half is in the tires. Over Six hundred Other COmISOr


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110'

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1980

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Figure 1:

Pounds of Rubber in a Typical U.S. Car (2-5)

ponents utilize the remaining material. Many different types of elastomers are used to meet the variety of thermal, chemical, and physical demands of these applications. The automotive environment provides extremes in temperatures, exposure to a variety of aggressive fluids, fatigue, abrasion, and exposure to chemicals in the environment. The wide variety of automotive operating conditions coupled with the multimaterial nature of the systems provides a complex set of interactions. The choice of an elastomer for use in a particular application is influenced by many factors (Table III) including the operating environment, component design, durability Table III:

Technical Issues for Automotive Elastomers • • • • • • • • • •

heat resistance fluid resistance low temperature flexibility fracture behavior fatigue characteristics long term chemical stability dynamic properties and NVH permeability frictional characteristics recycling capabilities


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targets, recyclability, use of recycled content in the component, manufacturability, quality, government regulations and economics (6).


In addition, the elastomers must last for a long time and be compatible with multimaterial systems. Future elastomer components are being designed with the goal of lasting 10 years or 150,000 miles for both passenger car and light truck. Most rubber compounds contain only 30-50% of base elastomers mixed with a variety of other materials (fillers, plasticizers, extenders, stabilizers, and curatives) in order to achieve the specific performance required. Because elastomer compounds are designed to maximize the performance, life and stability of components, these materials do not deteriorate rapidly and accordingly accumulate in disposal areas. However, the materials being disposed of may have value as the virgin elastomers range in price from less than $2.00/lb to over $55.00/lb. Recycling of Tires. Elastomer usage is dominated by the automotive industry. Thus, the automobile is the main source of post-consumer elastomers and we cannot look to other sources for major volumes of post-consumer elastomer material. Further, because of the large quantity (Table IV) of scrap tires (over 2 billion, with 240 million generated per year) and the fact that they are often concentrated in disposal areas (7), tires will remain the major source of post-consumer ground rubber for the near term. Table IV:

Projected U.S. Utilization of Scrap Tires (7)

• annual consumption of 328 million scrap tires by 1997 • annual generation of scrap tires - about 240 million tires • existing stockpile - over 2 billion tires The Scrap Tire Management Council in their 1992 "Scrap Tire Use/Disposal Study" suggested scrap tires could be used as fuel in a variety of potential applications because the energy content is essentially that of coal (7). They also projected asphalt/paving applications, civil engineering applications, and product recovery via pyrolysis (Table V)(7). Table V:

Alternative Scrap Tire Use or Disposal Methods (7) • supplemental fuel in cement kilns • supplemental fuel in pulp and paper mills • supplemental fuel in electricity generating facilities • fuel in dedicated tire-to-energy facilities • use in asphalt/paving applications • product recovery via pyrolysis


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K. B. Hoezen in summarizing the European situation and projecting the future noted that 23% of tires are currently retreaded, another 30% are recycled by various means, and the remaining 47% are disposed by landfilling (8). The potential for increasing the amount of retreading in Europe is considered very modest with only 25-30% of the tires being retreaded in the future (8). Total scrap generation is to be reduced by 10% (8). Recycling is to be increased to 60% (8). However, it should be noted that some parts of Europe currently classify fuel use as recycling. J. R. Dunn noted that 47% of scrapped tires in Japan are retreaded or reclaimed and 39% are used as fuel (9). By Japanese definitions this results in 86% being counted as reutilized (9). Putting Rubber Back to Use in the Vehicle. A number of the issues for recycling automotive elastomers are shown in Table VI (6). Most elastomer compounds form permanent chemical bonds and cannot be easily remolded. Thermoset elastomers are either reclaimed through a severe chemical process which significantly alters the Table V I :

• • • • • • • • • •

Recycling Issues for Automotive Elastomers

complexity of elastomeric compounds reutilization of thermosets post consumer recyclate (PCR) as a compounding tool recycling infrastructure identification of PCR elastomers availability non-tire PCR communication with product engineers past perception of poor quality consistent quality effect on part longevity

elastomer properties or are ground into particles. Reclaimed rubber can be suitable for use in some rubber compounds. Ground cured elastomers have been used in modest amounts as a component of rubber compounds in the past. Most of this recycled content usage has been of the pre-consumer variety not post-consumer. Further, companies would often return the ground pre-consumer material into the same compound from which it originated. Post-consumer recycled material (PCR) needs to be recognized as a compounding tool (10). That is, the compounds should be developed initially using PCR and not simply adulterated with PCR after the fact. Even as we focus on the use of post-consumer recycled material in elastomeric components, we must be careful that we meet the needs of the automotive environment as well as the stresses imposed by interactions with other systems and components. Ford Motor Company will not compromise on quality or performance when elastomer compounds containing recycled content are utilized. Ford announced recently that it is testing a compound containing post-consumer recycled tire rubber in brake pedal pads on some of its vehicle lines. It is already using postconsumer recycled tire rubber in some parking brake pedal pads and Aerostar step plates. Other applications for materials containing recycled elastomer content are being vigorously explored.


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Thermoplastic elastomers are often easily reprocessed. These materials account for about 15-20% of the non-tire automotive elastomer usage today and are continuing to make inroads into traditional thermoset elastomer markets (77). These materials may provide some aid to recycling in the future as well as a means of utilizing PCR. Challenges. Product engineers are being introduced to the use of post-consumer recycled material, but a dialog with the rubber industry is necessary for them to be aware of the choices they have available. The Rubber Recycling Topical Group of the Rubber Division, American Chemical Society and the Vehicle Recycling Partnership, under USCAR are but two of the many forums which have developed to allow exchange of precompetitive information on elastomer recycling. There are many challenges among the recycling technologies which need to be developed as shown in Table VII. Table VII: Development of New Recycling Technologies • • • • • •

devulcanization depolymerization multi-material coupling agents post-consumer material as compounding ingredient rapid, easy material definition low cost recovery and separation of rubber

New recycling technologies are needed to supplement those that we already have. Improvements in the technologies for devulcanization (breaking of crosslinks), depolymerization (breaking of backbone chains), and chemical modification are being explored as routes to high quality recycled material. In the past, use of reclaimed rubber and ground rubber was not always held to stringent performance requirements (e.g. in some low cost after market tires). However, there have been innovative uses of ground rubber to prepare thermoplastic elastomers with modest but useful properties. Recent advances in the surface treatment of ground rubber have significantly improved the physical properties of the compounds in which they were included. Further, some companies are already selling high value recycled rubber which meets stringent quality and consistency standards. The infrastructure to obtain steady, reliable sources of PCR of the various types of elastomers used in the vehicle is developing. The automobile companies are creating a demand for PCR in order to help stimulate this growth of the infrastructure as it makes economic sense in a free market place environment. The ingenuity of those who address the utilization of post-consumer recycled material is needed to provide rapid and effective means of identification of base elastomer types on parts coming from the vehicle. The availability of non-tire PCR needs to be increased so that we can address major areas such as the use of EPDM on the interior of the vehicle.



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The Future of Elastomer Recycling. Only a year ago Ford reached the conclusion that it was prudent to encourage the use of pre-consumer recycled elastomer content in components because of the state of the technology. The purpose was to stimulate the necessary technological developments permitting the use of recycled rubber. Then, post-consumer recycled materials will be phased in as the technology and supply infrastructure permit. While this is still true in part, the rubber industry has shown us that it has much to offer that we have not yet fully utilized. However, substantial technological developments are needed for elastomer recycling to reach its full potential. Ford intends to aggressively utilize post-consumer recycled elastomers in every application where it makes sense on the basis of performance and economics. Plastics Recycling Technologies So far most of the plastics recycling technologies have been developed for recycling non-durable consumer items, much of it in response to legislation at state and federal levels. Recycling of high density polyethylene (HDPE), polyethylene terephthalate (PET) and polystyrene has grown rapidly as a number of recycling facilities have been built. Success of this recycling business is derived from the sorting and collection programs of many municipalities providing a reliable supply of clean, segregated plastics. A good example of the success of packaging focused recycling is the use of recycled PET by Ford Motor Company. Since 1988, Ford has used over 23 million lb of recycled PET from 2-liter bottles (ca. 50 million bottles/year). The recycled PET is used in the grill opening reinforcement and luggage racks of several car lines. Contaminated and mixed plastics are extremely difficult to recycle. Technical efforts in the past have been focused on the development of separation processes and recovery of useful products from the individual plastic materials. Separation Techniques. Many techniques to separate plastics from scrap automobiles and municipal waste have been investigated with varying degrees of success. To assist in the manual separation, plastic containers and automotive parts are marked with codes to identify the material used. Virtually all household plastic containers now carry these codes, but the practice is different for the automotive industry due to the number and complexity of the codes needed to mark automotive plastic parts. Manual sorting has not proved satisfactory for the household waste because of high cost and misreading of identification marks. For this reason high speed automatic separators based on mechanical techniques are being developed and a few of these are now in use. But most of these separators are designed to handle only a very limited number of plastic items, e.g. household bottles. Other identification and sorting techniques based on density separation, bar code reading, computerized image analysis, infrared reflection, electrostatic charging, dissolution in solvents, selective melting, etc., are being investigated. When the number of mixed plastics is rather limited, some of these techniques show promising


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results. But none of these techniques are considered feasible for separating automotive shredder residue into reasonably pure polymer fractions. Reprocessing of Thermoplastic Waste. Clean thermoplastics can be easily reprocessed by using off-the-shelf equipment. Several hundred million pounds of polyethylene-terephthalate (PET) from pop bottles and high density polyethylene (HDPE) from milk jugs are reprocessed and recycled into useful products at a profit. With community support and consumer dedication, the separation of plastic articles, especially pop bottles and milk jugs, was achieved on a very large scale, laying the foundation for the recycling infra-structure we see today. But recycling of other waste plastic articles has not been as successful. Recycling of polystyrene foam, for example, is not as profitable as recycling of PET and HDPE and sometimes is unprofitable. Most thermoplastic scrap (except some prompt scrap) is contaminated with paint, adhesives, and other materials, e.g., paper, glass, other plastics, and metals. The recycling of this type of plastic scrap, which includes most automotive thermoplastics, presents problems not encountered in the recycling of household bottles. Because different types of plastics are usually not compatible, the reprocessing of mixed thermoplastics scrap, for example from automotive sources and especially from shredder waste, generally, does not yield valuable products. More research and development work is needed to develop technologies for recovering, separating, and purifying scrap automotive thermoplastics and recycling them into valuable products. To date, there are just a few successful cases of recycling automotive plastics. The recycling of PC/PBT bumpers from old Ford vehicles is one example. Scrap PC/PBT bumpers are collected at junkyards and body shops, the paint is removed, and the plastic material reconstituted by GE Plastics. The recycled bumper material is finding uses in several components of Ford cars. Another example is the recycling of PP from battery cases. Ford is using about 2.3 million pounds per year of the recycled PP for splash shields. The recycling of more difficult components (e.g. vehicle interior, seats, carpeting, etc.) are being investigated by Ford, GM, Chrysler, and many collaborators. It is believed to be just a matter of time before many more automotive components will be recycled profitably. A process has been developed jointly by ARCO Company and Ford Saline Plant to recycle instrumental panels made of styrene maleic anhydride (SMA) plastic covered with polyurethane foam and PVC skin. The separation process yields 99.8% pure SMA, which after addition of stabilizers is used in new instrument panels. Reprocessing of Thermosets. Thermosets in general cannot be reprocessed like thermoplastics. An exception to this rule is polyurethane foam which is converted to carpet underlay and RIM scrap which can be pressed (under moist heat) into simple shapes to fabricate mud guards or sound deadener pads.


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Both the SMC and RIM scrap can be ground and added to virgin materials. In the case of SMC, up to 15 percent of finely ground scrap can be mixed with virgin SMC and molded without any deleterious effects on the strength of the molded part. This process does not appear to be economical at this time. A new process, developed by Phoenix Fiberglass of Oakville, Canada, separates the glass fibers from the fillers and resin in SMC. The chopped glass fibers are used in bulk molding compounds (BMC). The remaining material is pulverized and sold as filler for SMC and BMC applications. Pulverized RIM scrap can be mixed with RIM prepolymer up to 10% and the mixture reprocessed. Although the utility of this technology has been demonstrated at laboratory scale, some of the processing details and economics need to be established for commercial applications. Reprocessing of Mixed Plastics. Mixed thermosets and thermoplastics, sometimes, can be processed into low strength products using specially designed extruders and molding machines. In such a process, thermoset material functions as a hard, nonmelting filler and thermoplastic functions as a binder. Before the material is fed to the extruder, it must be shredded, chopped, pulverized, or densified and mixed with other ingredients (additional thermoplastic to provide enough binder, pigments, stabilizers and processing aids) to achieve consistent processing conditions and product quality. A number of commercial installations are processing mixed plastics to produce plastic lumber, fence posts, park benches, agricultural stakes, boat docks, walkways, etc. Recycling of mixed plastics has been slow to develop because the products generated are of low value and, in many cases, are not price competitive. Plastic lumber, for example, is at least twice as expensive as natural lumber. Trends in Vehicle Recycling The main issues concerning vehicle recycling today are how to economically reclaim plastics, glass, and other non-metallic materials from scrap vehicles so as to minimize the environmental impact of ASR, and how to design future vehicles to enable total vehicle recycling. Much of the action today is focused on recycling automotive plastics. Some of the important trends are described below. Design For Disassembly. Preliminary studies on components dismantling from vehicles, conducted by Ford Motor Company in collaboration with SPI and ARA, have demonstrated that for many components the dismantling time is too long to be economical. That is, the cost of labor to dismantle auto parts exceeds the value of the recovered plastic materials. In addition, in some automotive parts, different materials are put together in such a way that separation is not practical. New design guidelines have been developed by Ford and distributed to engineers and suppliers in early 1994 to address the recycling roadblocks found in present and older models. These guidelines, which will be integrated into the product design and development process, will facilitate the recycling of future vehicles. The guidelines cover recommendations for materials selection, fasteners, adhesives, and


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design for quick disassembly. In some cases, standardization of components might be advantageous to the industry. For example, in order to remove quickly engine coolant, or any other vehicle fluid for that matter, it may be easier for dismantlers if all vehicles were to have a common drain fitting with the same size and at about the same location. Trends in Automotive Plastic Materials. Plastic materials serve many diverse functions in automotive applications. Today, there are many different types, and within each type different grades, of plastics. Generally, plastics usage in a typical vehicle is of the order of 10% by weight. Managing too many plastic materials can be overly complex and expensive. Do we really need the many different types and grades of plastics in vehicles? Probably not. In fact, Ford Motor Company recently reduced dramatically the number of different grades of certain plastics in the Company's vehicles. This action reduced cost but did not sacrifice performance. An emerging trend in the automotive industry appears to be the minimization of the number of plastics to a small core group and wherever feasible using plastics which are compatible with each other. While this trend was originally driven by cost considerations, today, it is also supported by recycling. Obviously, decreasing the variety of plastics will enable easier sorting and collection. But recycling adds some new demands to the selection of plastic materials. First, the materials should be recyclable with existing technologies. The availability of existing and proven technologies should be emphasized since many interest groups invariably tend to claim recyclability of their products whether or not recycling is occurring commercially. Second, the various plastic types used should be compatible when re-processed together. This is especially important when a component is made of two or more plastics and separation is not practical. Along this line it would also be desirable to have the fasteners easily accessible for quick removal or the adhesive to be compatible with the substrate materials. These developments, obviously, generate some anxiety among suppliers of the automotive industry. How many and what are the materials of choice? There is no simple answer and, probably, may not be for quite a while. The trend suggested above involves many inter-related factors and the process of reducing the number of materials is complicated and inherently slow. It should be emphasized that quality, performance, function, and cost are paramount values in the automotive industry and whatever the materials of choice are going to be, they will have to have these values. Managing Substances of Concern. Some vehicle components contain substances that can be toxic under certain circumstances (e.g. lead from the battery) and if not managed properly, can contaminate the ASR generated during vehicle shredding. In general, proper dismantling procedures prior to shredding would eliminate this problem, i.e. removal of battery, all vehicle fluids, air bags, etc. When properly


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removed and separated, these materials (engine oil, gasoline, zinc, lead, etc.) can be recycled and sold profitably. In other cases, some substances of concern may be compounded into the material formulation (e.g., Cd based pigments and lead stabilizers in plastics) or may be an integral part of a component (e.g. a chrome-plated bumper). The trend in the automotive industry, today, is to find non-toxic substitutes whenever possible and practical. Obviously, the automotive manufacturers must rely on the technical ingenuity of their suppliers to come up with acceptable substitutes. For example, beginning with the 1995 models, Ford Motor Company will only use Cd free pigments in plastic and paint formulations which were developed by its suppliers. Another good example is the substitution of CFC by HFC in air conditioning systems. Recycling Alliances and Partnerships. The issues of recycling are equally important to auto manufacturers, parts suppliers, and raw materials manufacturers. It is therefore not surprising to see the development of joint projects and alliances among various organizations having common interest in advancing vehicle recycling. Some major alliances in U.S. are: Vehicle Recycling Partnership (VRP). This is a consortium of Chrysler, Ford and General Motors which was established in November 1991. The objectives of the VRP include addressing all pre-competitive technology issues and concerns related to material recovery and recycling from scrap automobiles. Major emphasis is on the development of technologies useful to recycle materials and components from scrap vehicles, establishment of an understanding of the major technological and economic issues associated with various alternatives, and the development of criteria for materials selection and design guidelines which will facilitate recycling of future vehicles. Recently, the VRP opened a vehicle recycling development center to study in detail the issues of dismantling and reclamation of parts and materials from scrap vehicles. Some of the goals of the center are to identify what are the hindrances to recycling, devise methodologies and tools to overcome these hindrances and facilitate higher rate of recycling, and develop generic design guidelines for future vehicles. Specific projects at the Vehicle Recycling Center include development of equipment and procedures for quick drainage and recovery of fluids, recycling of seats, carpets, and instrument panels. The VRP collaborates with the American Plastics Council (APC), Automotive Recyclers Association (ARA), and Institute of Scrap Recycling Industries (ISRI). American Plastics Council (APC). A group of about 30 resin manufacturers formerly known as the Council for Solid Waste Solutions. APC is developing recycling technologies of plastics in general. A sub-group of APC is the Automotive Committee whose primary goal is to catalyze the recycling and recovery of automotive plastics. APC has established a multi-products recycling facility (MPRF) in Boston to study recycling technologies of various plastics.


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As stated earlier, ARA and ISRI represent the existing infra-structure of recycling scrap vehicles. Today, these organizations collaborate with the VRP and APC in developing advanced technologies that will increase the recycling rate of scrap cars. In addition, agreement of joint projects with Argonne National Laboratory has been reached.


Conclusions Vehicle recycling activities have been going on successfully for more than 70 years. The existing infra-structure of dismantlers and shredders is capable of recovering 75% by weight of scrap cars. It is especially important to note that today this vehicle recycling is profitable. In order to continue and improve the impressive track record of the existing auto recycling industry it is essential to have a free market-based system of vehicle recovery. The driving force for increasing recycling rate should be profit opportunity through development of new technology and products. Many industries and companies are or will be affected by the new ways of doing business and, hence, cooperation is critical. Cooperation in a market-driven economic system will ensure continued improvement of automobile recycling. Literature Cited 1. Baumgartner & Associates, Inc., W. Z., Shredder Residue: Environmental Information and Characterization Under RCRA, Recycling Research Foundation, Washington, D.C., May, 1992. 2. 1994 Ward's Automotive Yearbook, p. 36, Fifty-Sixth Edition, Ward's Communication, Detroit, Michigan, 1994. 3. Automotive Materials in the 90's: an overview and forecast of technology and applications, Ward's Communications, Detroit, Michigan, 1989. 4. 1992 Ward's Automotive Yearbook, p. 36, Fifty-Fourth Edition, Ward's Communication, Detroit, Michigan, 1992. 5. 1993 Ward's Automotive Yearbook, p. 36, Fifty-Fifth Edition, Ward's Communication, Detroit, Michigan, 1993. 6. Pett, R. A.; Gullen, L. R., Automotive Elastomers - The Challenge Continues, Fall Technical Symposium, Detroit Rubber Group, Oct., 1992. 7. Kearney, A. T., Scrap Tire Use/Disposal Study, Scrap Tire Management Council, Oct., 1992. 8. Hoezen, K. B., European Efforts in Rubber Recycling, 144th Meeting of the Rubber Division, ACS, Orlando, Florida, Oct., 1993. 9. Dunn, J. R., Recycling/Reuse of Elastomers - An Overview, 144th Meeting of the Rubber Division, ACS, Orlando, Florida, Oct., 1993. 10. Smith, F. G., Ground Rubber Use: Emerging New Market Trends, 144th Meeting of the Rubber Division, ACS, Orlando, Florida, Oct., 1993. 11. Rader, C.P., Thermoplastic Elastomers, 142nd meeting of the Rubber Division, ACS, Nashville, Tennessee, Nov., 1992. RECEIVED June 12, 1995


Automotive Recycling - ACS Publications - American Chemical Society

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