100% Post-Consumer Recycled Nylon 6: Repolymerized Resin Provides Full Mechanical, Physical, & Aesthetic Properties 2000-01-1394

The increased use of recycled resins can create a dilemma for automotive designers. On the one hand, there is a growing initiative to increase recycled materials content on vehicles, globally. On the other hand, traditional methods of recycling polymeric materials -both thermoplastics and thermosets - can lead to degradation of engineering, mechanical, processing, and / or aesthetic properties of the resin. In an era where quality rules, this situation forces designers to accept a much lower percentage of recyclate than they might otherwise wish to use or risk unacceptable property loss in molded parts - something no automaker can “afford ” for long. Hence, a valuable feedstream of materials (polymers) often ends up destined for a landfill once many consumer products are broken down and more easily reusable or recyclable materials are salvaged.

As a case in point, each passenger car built globally contains an average of 15 - 20 kg of nylon polymers. Because of the excellent performance characteristics of this family of engineering thermoplastics, nylon polymers would be attractive candidates for reuse on vehicles

• If there were a way to reduce or prevent property loss during reclamation and reprocessing, and
• If automakers and their suppliers could secure a ready supply of this recycled resin.

Fortunately, a new technology breakthrough now makes it possible to meet both of these goals, at least for nylon 6 resins.

Using waste nylon 6 carpet as feedstock - with the option of accepting painted or unpainted, pigmented or unpigmented nylon 6 parts from other industries, including automotive - the patented process first breaks nylon 6 down to its monomer, caprolactam. The recycled caprolactam is then repolymerized back into new “virgin ” nylon 6 resin that can be further modified with fillers, colorants, and additives to create resins that are indistinguishable from those made from conventional “virgin ” caprolactam feedstock. This paper briefly discusses the nylon 6 repolymerization process, with emphasis on the kinds of applications these materials can be used for, and then speculates on the potential impact of this technology on closed-loop recycling programs in the automotive industry.