Plastics Growth in Autos Steadies

The automotive materials war rages on as steel, aluminum and plastics suppliers continue to vie for a larger piece of the pie. All tout the advantages of their respective material, but the king of the hill is still steel, with about 70 percent of the composition of an average car. Plastics usage has grown dramatically in the past decade, and will continue to grow – but at a much slower pace, according to leading automotive designers. The average new car sold in North America today has about 8 percent by weight of plastics, or about 365 pounds. That figure compares with about only 60 pounds per car in 1970.

Plastics use in cars and light trucks in North America is expected to grow from just more than 3 billion pounds this year to more than 4 billion pounds by 2006, according to a new study by Market Search Inc., Toledo, Ohio. The additional 1 billion pounds will come from modest growth of plastics used on each vehicle, along with an increased number of vehicles on the road. Growth is expected in the use of polyethylene, reinforced nylon, acrylic glazing, sheet molded composites, acrylonitrile butadiene styrene-polycarbonate alloys, reinforced thermoplastic polyesters and polyolefins, and polypropylene.

Other types of plastics contained in autos include polyurethanes, polyvinyl chloride, styrene maleic anhydride, polyacetals and polyphenylene-based resins, but these types are not expected to experience dramatic growth, and the use of some resins – such as PVC – is actually declining.

"Plastics usage in autos will be at the 8 percent peak for a while," says Irv Poston, manager of polymer composites for General Motors, Warren, Mich., and chairman of the Vehicle Recycling Partnership in Highland Park, Mich., a subgroup of the United States Council of Automotive Research, Dearborn, Mich. "Even at the turn of the century, and for some time after that, I don’t think plastics and composites will be above the 10 percent mark."

Significant leaps in auto plastic growth will be limited due to the auto industry’s inability to change quickly, says Poston. "The manufacturing process right now is geared toward steel, and it is very hard to change that in a short period of time." Normally for a large-scale change in auto composition to take place, a whole new plant has to be built. This is not without precedent – Corvette retooled to incorporate plastic composites in its body panels, and Saturn employs several new manufacturing techniques for plastics in its cars.

"Also, with plastics, and even aluminum, the assembly, fabrication and finishing is different," says Poston, "and there are several challenges to overcome in all of those areas." One challenge involves the joining of various plastic and composite parts because special adhesives have to be used, and those adhesives have to hold up to the normal wear and tear of driving.

Still, plastics are making inroads, and are now the material of choice for bumpers, dashboards, arm rests, seat components, wheel covers, inside trim and door panels, and grilles. In addition, various plastic materials are expected to make gains in the areas of bumper beams, gas tanks, engine intake manifolds, outside body panels, hoods and decklids.

As this movement continues, automakers are looking at designing cars with fewer part-intensive assemblies, and instead plan to employ single-molded plastic structures. Also, light metal frames may be reinforced with plastic shells, and reinforcing beams in doors and crossmembers may be made increasingly out of some type of plastic composite.

The primary reasons for the advancement of plastics and plastic-based composites in cars and trucks is the material’s light weight, flexibility in design, low tooling and retooling costs, non-corrosion nature and even strength. Car manufacturers are being pressed to deliver vehicles with higher mile-per-gallon ratings, and reducing a vehicle’s overall weight is one way to tweak out better gas mileage. And weight is an even greater concern for electric and hybrid-fuel-powered vehicles.

In 1993 the auto industry was challenged by the White House to develop a high mileage vehicle. The Partnership for a New Generation of Vehicles – a collaboration of the Big Three automakers to make a more fuel efficient car – was born. The Big Three also established USCAR to collaborate on advances in vehicle technology.

However, any significant change in automobile material usage means changes on the recycling and dismantling end. With the integration of more types of plastics and a greater percentage of plastics by volume in cars, recyclers have to develop new automotive recycling solutions.

Despite the current overall stagnation of plastics use in autos, plastic-based composite materials appear to be making gains. Sheet molding composite, which is also known as thermoset polyester, is one composite that has experienced increased usage during the last six years. The material is mainly used for body panels and structural parts. SMC consists mostly of fiberglass and calcium carbonate molded in a plastic resin.

In 1990, U.S. auto makers used 135 million pounds of SMC, and by the end of this year, this figure is expected to reach 240 million pounds – 20 percent more than was used in 1995. By the year 200, more than 390 million pounds of SMC is projected to be used, according to the SMC Automotive Alliance, Troy, Mich. Currently, SMC is used for more than 370 automotive parts – 70 of which are new applications for the 1996 model year.

Ford is the fastest-growing user of SMC. If auto sales hit Ford targets, the company expects to use about 38 million pounds of SMC this year – a 211 percent increase from 1993. Ford and other automakers are using SMC in a wide range of parts, such as body panels, bumpers, spoilers, grilles, hoods, decklids, integrated front-end modules, glove box doors, steering column covers, radiator supports, fuel tank shields, cross-vehicle beams, wheel fenders and engine covers.

Another area where plastic composites could advance significantly is the conversion of large automotive structural assemblies, such as cargo boxes for pickups, and complete plastic monocoque bodies in which the body is integral with the chassis. Recently, the Big Three, under the Automotive Composites Consortium of USCAR, obtained the use of the former Gentile Air Force Base in Kettering, Ohio, to conduct research and development on manufacturing these large plastic structures. The main goal of the R&D is to reduce the production time to make the cargo box for pickups, and to prove the manufacturing process cost effective.

This is important because now plastics is moving beyond bumpers, glove box doors and arm rests, and into areas previously considered appropriate only for metals. For instance, if the cargo boxes on pickups are replaced sometime in the future with plastic ones, it could mean the displacement of up to 800 pounds of steel per truck.

Overall, there will be more use of composites that do not dent, rust or chip, and, increasingly, can also be recycled, says Red Cavaney, president of the American Plastics Council, Washington. "Drivers could be ‘cocooned’ in a high-tech plastics interior– with bolsters, air bags and cushioning to better absorb the impact of collisions."

The use of resin-based composites would be needed to build a car that is known in automotive engineering research circles as the hypercar. A hypercar would be made mainly from plastic-based composites in a monocoque design; propelled by hybrid propulsion systems that use fuel cells, regenerative braking, high-energy-storage flywheels, small high-efficient motors, super capacitors and small engines; and have skinny tires with specials compounds that reduce rolling resistance. Much of this technology already exists.

One place where the hypercar theory and technology is being examined is at The Hypercar Center of The Rocky Mountain Institute, Snowmass, Colo. The institute is a design think tank where associates look beyond conventional methods to tackle engineering challenges. In 1991, RMI first proposed a hypercar model, and since then has modified its design.

"It’s a composite car that can achieve between 100 to 150 miles per gallon because it is so lightweight that it needs less power to move," says David Cramer, a research associate at RMI. "Through our computer modeling, we have shown that this car not only gets better gas mileage, but is actually safer than a comparable car on the road today."

The reasons for the added safety are many. "Composites are stronger than steel, and are more absorbent in crashes," says Cramer. "Also, because the vehicle is lighter, there is no need for a massive engine up front. Therefore, there is more space inside to absorb impacts, and you don’t have a big engine that can come crashing through the front dash."

Hypercars would use one-tenth the amount of steel, twice as much plastics, and a fourth to a tenth as much fuel as a comparable car built today. Most of the hypercar’s subsystems and components would become smaller, with some disappearing altogether. Since 1994, RMI reports that 25 firms have committed more than $1 billion to the development of ultralight hybrid vehicles.

GM built a prototype ultralight a few years ago, but it was made of expensive carbon-based composite, and was not very practical. "Overall, I would say that there is really no hard push for a hypercar at this time by any of the major automakers," says Poston. "But a lot of vision has been put into the hypercar model, and it has created a lot of thought-starters."

It is a myth that a car loaded with composites would not be as recyclable as a conventional vehicle. "In fact, a composite car would be very recyclable," says Cramer. "The composites can be recovered and reused again through various methods. And even if our hypercar model were to go through the recycling infrastructure that is in place today, there would still be less material heading to the landfill than from a conventional car."

Whether or not the hypercar or another plastics-intensive car will ever make it to production will depend not only on developments in technology and attitudes of drivers, but how recyclable such a vehicle would be. "The infrastructure is not in place to recycle all the plastics from autos," says Al Maten, director of durables for APC. "Progress is being made, but this industry is still very young."

In fact, today composites used in auto applications are already being recycled. The SMC industry is making gains in recycling the material back into new composite parts and in other applications. Currently, there are more than 20 parts containing recycled SMC, with about 10 more parts planned for 1997 models. Most of the SMC applications are for body panels – parts that are easily removed at the dismantler level. To facilitate this work, the SMCAA has set up an SMC recycling infrastructure.

The Alliance has designated R.J. Marshall Co., Southfield, Mich., to be the primary recycler for SMC scrap. The mineral company, which specializes in providing fillers to several industries, currently is evaluating the scrap at its plant in Detroit. But company officials warn that the use of SMC all depends on profitability. "Market forces will dictate what we can accept and process," says Dick Marshall, president.

At the Southfield site SMC scrap is milled and separated into three materials: composite filler, and milled and chopped-strand fiberglass. The composite filler is used as a replacement for calcium carbonate, ranging from 6 percent to 25 percent by weight. Calcium carbonate constitutes about half of the raw materials by weight used to make SMC. The resin also can be made from post-consumer polyethylene terephthalate bottles.

While substituting recycled SMC for calcium carbonate is classic closed-loop recycling, the composite filler also has the added benefit of decreasing the overall weight of the part. "There’s no degradation of properties when recycling SMC," says Tom Harth, past chairman of SMCAA’s Technical Committee and current compounding manager at Eagle-Picher’s Plastics Division, Grabill, Ind. "In fact, automakers have reduced the weight of a single SMC component up to 10 percent by using composite filler."

Composite filler has been used in interior trim panels on Chrysler’s Ram Van, and in the spoiler of the Neon. Other cars using parts with the filler include the Chevrolet Corvette, Volkswagen Passat and Audi 100.

The milled and chopped strand fiberglass that is not used in new SMC parts is diverted mainly to companies that use it for friction, putty and reaction-injection molding applications, or for stucco applications and in bulk molding compounds.

SMC and other types of composites can also be recycled with a low-heat pyrolysis process such as the one used by Adherent Technologies, Albuquerque, N.M. Other recyclers who use pyrolysis processes to recycle tires are now expanding into the processing of various types of plastic scrap.

Solvolysis is another method to recycle composites. This process uses a special solvent to break down the resin matrix while leaving the fibers intact. One of the most developed forms of solvolysis is called methanolysis where the composite is heated in the presence of high-pressure methanol. the methanol decomposes the plastic resin into a reagent that is vaporized and condensed separately, and formed into fibers which can be reused.

While the development of numerous different engineered plastics is great for automotive design, it also makes recycling plastics from autos more challenging. Parts like bumpers, hoods and deck lids are easy to remove at the dismantler level, but integrated ones are not. And as plastics move further into undercar applications, these parts are most likely destined for the shredder. The plastic then becomes part of an even more difficult material stream to recycle called automotive shredder residue, or shredder fluff.

Efforts are ongoing to establish a viable recycling solution for shredder fluff which is estimated to contain about 50 percent plastics, 15 percent fabric, 8 percent ferrous metals, 7 percent glass, 6 percent rubber, 5 percent wire harness, 4 percent nonferrous metals, 3 percent wood and 2 percent paper.

One method is to prevent the material from entering the shredder fluff stream in the first place. Projects at wTe Corp., Bedford, Mass., and MBA Polymers Inc., Berkeley, Calif., which are partially funded by APC, have demonstrated that items such as seats, dashboards and other integrated plastic parts can be recycled.

Another effort by VRP and Argonne National Laboratory outside Chicago also showed that seat foam can be removed and cleaned to be reused to make new car seats, carpet padding and sound suppression. For VRP this is a new effort, because to date it has focused primarily on design guidelines for auto engineers to make vehicle disassembly easier, and has delivered a preferred practices list to the automakers. "Now VRP is going to the next level and expanding its horizon by working with companies that process these materials," says Maten.

The word about "designing for recycling" is definitely getting out to the engineers and others, says Poston, who says that the preferred practices will start to be implemented in the 1998 models. "We have focused on dismantling for reuse; now what we want to do is show that dismantling for recycling can work, too."

Another firm that plans to tackle shredder fluff is HGI/Result North America, Asheville, N.C., which is currently marketing a system that uses a supersonic vortex separator in conjunction with several other pieces of processing equipment to separate the different fines in shredder fluff. The system, which uses no chemicals or heat, can also recycle complex composites, according to company officials. Result plans to have its first plant in operation in Toronto by the end of 1997.

GM has been experimenting with a pyrolysis process for the last seven years that will recycle shredder fluff. Reportedly, the automaker is pleased with the latest refinements to the process and is expected to start a large-scale prototype operation soon.

Other efforts have pelletized fluff for use as fuel in cement kilns or to be incinerated in other types of facilities.

Finally, Toyota has started recycling shredder fluff at a plant it owns near Nagoya, Japan, that can recycle about 80 percent of the fluff waste stream. At the plant, fluff goes through 17 sorting and processing stations and is separated into 12 different materials. From there, the 12 materials are further processed using air and gravity sorters that further recover copper, polyurethane foam, glass and fabric.

The remaining 20 percent of the fluff stream is still deemed unrecyclable and is vitrified and burned as fuel or landfilled.

Shredder fluff presently accounts for only 2 percent of landfill waste in the United States, but Poston says that should not lessen the importance of recycling it.

"Pyrolysis, solvolysis, mechanical separation, density separation – these are all good methods for recycling fluff. However, the cost to landfill it is certainly cheaper right now, and that is a major challenge."

 A CONSCIOUS EFFORT

Automotive engineers today are more conscious than ever before of the recycling implications of their designs, says Steve Gumplo, communications director of APC. "More and more engineers are asking about the recyclability of a part."

Maten points to aggressive efforts by the automakers and suppliers to create infrastructure for recycling automotive plastics. "GM’s Saturn division is collecting and reusing post-consumer fascia scrap as a feed stream for wheel liners," he says. "Dow and GE Plastics are purchasing plastic scrap from autos to reuse in not only auto applications, but non-auto applications as well."

Many of these efforts are necessitated by automakers that require at least 25 percent recycled content in parts. According to Ford, using recycled plastic created savings of more than $1 million during 1995.