Title: Closed-Loop Recycling of Monomaterial Door-Panel Systems
text: Pressures to increase the recyclable and recycled content of passenger vehicles are accelerating. In Europe, there is interest in eliminating halogenated polymers. Globally, more and more concern is focused on materials and methods that are ecologically friendly. Automakers and their suppliers are being encouraged to design and assemble components in new ways to facilitate separation, identification, and resource recovery at the end of the vehicle’s useful life - something that is not only good for the environment, but also the bottom line. One area of the vehicle that has proved challenging for applying such design for disassembly and recycling (DFD/R) principles has been the interior, owing to the sheer number of materials used there, and the great number of laminate structures that make disassembly nearly impossible. A good example is a door panel inner, which typically consists of a rigid plastic substrate, a foam pad, and a vinyl, leather, or cloth covering. This component is usually comprised of different materials tied with adhesives and polyester scrim fabrics. Fortunately, recent material developments as well as process enhancements have now made it possible to quickly and efficiently manufacture all-olefin door panels without adhesives or scrim, making the monomaterial door panels excellent candidates for recycling. But how recyclable are these systems? A recent manufacturing study successfully recycled fully covered door-trim panels comprised of an olefin-based coverstock, a cross-linked olefin foam pad, and a polypropylene (PP) substrate. Processing scrap was chopped and reintroduced - at predetermined weight ratios - back into the virgin resin feedstream used to produce additional PP door substrates. A variety of tests were performed both on plaques and full door panels comprised of varying ratios of virgin + recycled material to see if the presence of the recycled material affected any physical or mechanical properties, processability, or other engineering specifications. The results of this testing program are presented here, along with recommendations for implementing a closed-loop recycling program.