Several steps toward recovery
Good for the environment, good for business
Last September, DaimlerChrysler Corp. began testing plastics recycling technology that could help the company achieve its goal of producing vehicles that are 95% recoverable by 2005. The project represents the second phase of DaimlerChrysler's CARE (Concepts for Advanced Recycling and Environmental) Car Program. The goals of the program are to reduce the amount of automobile waste going into landfills by one-third and to provide a source for high-quality recycled plastics that can be used to produce new automotive parts while simultaneously achieving cost savings in the production of new vehicles.
"This project is not only good for the environment, it is good business for DaimlerChrysler," said Bernard I. Robertson, Senior Vice President-Engineering Technologies and General Manager-Truck Operations. "By recycling the plastics from old cars and trucks, we believe we can reduce the cost of producing new vehicles by millions of dollars a year."
If successful, the program could also provide a profitable new market for automotive recyclers in recycled plastics, polyurethane foams, and copper. The three firms working with DaimlerChrysler are Recovery Plastics International of Salt Lake City, UT, which developed the automated skin-flotation process to separate plastics from other automotive shredder residue; and automotive recycling companies, New York-based Hugo Neu Corp. and David J. Joseph Co., which has operations in the U.S. and Europe. Skin flotation is the recovery of plastics from ASR—the left-over plastics, textiles, and glass present once the rest of a vehicle's materials (mostly metal) are recovered for reuse.
 Feedstocks are separated, pelletized, and tested for quality and performance during the manufacture of RETAIN, the result of an alliance between Dow Automotive and MRC Polymers. |
Plastics present a recycling challenge because they are difficult to separate since each kind of plastic has different physical characteristics. Skin flotation involves adding different chemicals to plastics in a hot water bath. These chemicals react only with certain plastics and cause air bubbles to attach to the plastic and float. They are then skimmed off the top of the water bath.
Since rubber contaminates plastic materials, it is important to separate it from plastics. This process involves first using skin flotation, which causes most of the plastics and a small amount of rubber material to bubble and float. A process called air aspiration is then used to remove the rubber from the plastic materials obtained from the skin flotation. When air aspiration is used, material goes through a conveyer and, when it hits a certain point, an air-suction tube sucks the lightweight materials (plastics, textiles, foam) up the tube, and heavy materials, such as rubber, fall out of the material stream.
In April 1999, DaimlerChrysler unveiled two Dodge Stratus sedans developed jointly with 26 supplier companies that demonstrated the potential of increasing recycled materials in new vehicles. More than 500 parts were modified to increase the content of recycled material in tires, seats, instrument panels, trim, floor mats, sun visors, fuel tanks, airbag systems, seatbelts, door handles, carpeting, fascias, taillamps, body trim, mirrors, and underhood plastic applications. The recycled materials used were made of waste from plastic bottles, glass, foamed material, carpet, and used tires; about 40% of the plastic materials used in the vehicles were from recycled materials.
As a result of the project, vehicle mass was reduced by 3 kg (7 lb), and seven types of plastics were eliminated, reducing the complexity of separating plastic components for recycling. According to DaimlerChrysler, the vehicles met all requirements for comfort, performance, quality, emissions, and safety.
DaimlerChrysler has plans to incorporate knowledge learned from the CARE cars into future production vehicles. "To do that, we will need a reliable source of recycled materials that meet our requirements for quality and purity," said Susan Yester, Senior Manager-Vehicle Recycling Programs.
There is much ongoing research and development among suppliers directed toward becoming the source that Yester referred to. For example, Dow Automotive has entered an alliance with MRC Polymers to provide a new family of resins, RETAIN, that will meet increased demand for recycled materials in the automotive market. The RETAIN polymers are developed using post-industrial and -consumer material feedstocks and can be used for instruments panel topper pads, defroster grilles, consoles, HVAC ducts, and door trim. Outside the vehicle, RETAIN is suitable for luggage racks, body side moldings, light housings, wheel covers, mirror housings, grilles, and exterior trim. Potential underhood applications include grille opening reinforcements, engine covers, evaporative canisters, and reservoirs.
