DuPont composite recycling technology takes radiator tanks from landfilled cars (bottom) and produces nylon materials that make new tanks meeting rigorous performance requirements.

July 22, 2003/CHICAGO, Ill,  ”  New DuPont Composite Recycle Technology marks a giant step forward in helping automakers meet the European Union's mandates for end-of-life vehicle (ELV) closed-loop recycling with a cost-effective technology to recycle large, glass-filled nylon automotive parts. Results of "in-use" testing of recycle-content material generated by a development program with DENSO Corporation show Composite Recycle Technology can be one of the most effective technologies.

"We expect this technology will increase the recycle ratio of end-of-life vehicles in the future," said Hiroyuki Wakabayasi, general manager of the Material Engineering R&D Department of DENSO Corporation

The European Union directive requires that 85 percent of a vehicle, measured by weight, be capable of recovery and reuse by the end of 2005 (the current figure for recycling is about 75 percent, which relates to the metal content).

At the NPE 2003 plastics exhibition, Dr. Bill Hsu, vice president – global technology for DuPont Engineering Polymers disclosed results of the first detailed studies of nylon materials produced at a prototype recycling plant in Canada. The studies, conducted by DENSO Corporation in collaboration with DuPont, confirmed the process's capability to convert nylon auto parts recovered from scrapped vehicles into glass-reinforced nylon resins and parts with properties equivalent to those of virgin nylons.

"The studies clearly show that our proprietary Composite Recycle Technology process can provide a workable, cradle-to-cradle solution for radiator end tanks," said Dr. Hsu. The process can likely be adapted to recycle air-intake manifolds, and other glass- or mineral-filled thermoplastic parts, he added.

"Composite Recycle Technology can reduce the amount of material going into landfills at the end of a vehicle's life. It also has a smaller environmental footprint and a higher financial return than alternatives we have evaluated, including incineration with energy recovery," Dr. Hsu said. "This development program illustrates the DuPont sustainability journey to deliver technologies today that are good for society, good for the economy and good for the environment."

The new prototype plant can produce about 55 kg of recycled nylon per batch. Its capacity allows production of sufficient quantities of materials for compounding, property testing and molding of parts for evaluation. The feedstock for the study consisted of 500 radiator end tanks collected from scrapped end-of-life vehicles in Japan. All of the tanks were made of glass-reinforced nylon 66. The tanks were dirty, and the material had been degraded by years of contact with hot engine coolant.

To reprocess them, the tanks were first ground up. The ground particles were fed into the prototype plant's reactor, where they were dissolved at elevated temperature and pressure. Glass fibers and other insoluble ingredients and contaminants were removed by filtration. The next step was to precipitate the dissolved nylon 66 from solution. During drying, the precipitated material was heated, inducing solid-phase polymerization to restore the polymer's molecular weight to the same level as that of virgin nylon.

The recovered nylon 66 polymer was compounded with glass fibers and subjected to a series of tests. Mechanical properties, resistance to aggressive liquid coolants and molding characteristics were equivalent to those of virgin nylon resins. Radiator end tanks were molded from the reprocessed material, and they were subjected additional tests, including high-temperature creep, high-pressure cycling, vibration and low-temperature impact. Results were very similar to those obtained with tanks made from virgin materials.

DENSO Corporation, headquartered in Kariya, Aichi prefecture, Japan, is a leading global supplier of advanced automotive technology, systems and components. Worldwide, the company employs 90,000 people in 31 countries and regions including Japan. Consolidated global sales for the year ended March 31, 2003, totaled US$ 19.4 billion. For further information, please visit http://www.globaldenso.com/.

DuPont is a science company. Founded in 1802, DuPont puts science to work by solving problems and creating solutions that make people's lives better, safer and easier. Operating in more than 70 countries, the company offers a wide range of products and services to markets including agriculture, nutrition, electronics, communications, safety and protection, home and construction, transportation and apparel.