Tertiary Recycling of Automotive Plastics and Composites

Abstract

The use of engineering plastics and composites in automotive applications is increasing to achieve weight reductions and the accompanying performance increases. These materials are difficult to recycle using conventional technologies because they are contaminated with metals and paints or are cross-linked polymer structures. A novel tertiary recycling process is being developed as an economical means for recycling scrap automotive plastics and composites. Early development work on this process for recycling scrap aerospace composites and electronics shows that it can convert a variety of polymers and composites into low-molecular-weight hydrocarbons at temperatures near 300'C. The hydrocarbons produced can then be reused as chemicals, fuels, or monomers. Metal, glass, fillers, and fibers are separated from the hydrocarbons during the process and can be reclaimed for reuse. Initial feasibility studies have shown that the proposed catalytic conversion process is effective for recycling plastics and composites used in automotive parts. This process does not require presorting of plastic wastes and allows fibers and fillers to be reclaimed for reuse. Conversion products from recycling sheet molding compounds (SMC), auto shredder residue (ASR), and scrap mixtures of automotive plastic body panels show that commercial recycling plants based on the catalytic conversion process should be an economical alternative to landfilling.