DSM and AlliedSignal floor the competition with carpet process
15 Jan 2000
DSM and AlliedSignal are to join forces for a project to recycle nylon carpet fibres into high-quality caprolactam. With a plant planned for the US, the venture will use a new process developed by the partners, which is claimed to cost no more than a conventional caprolactam plant.
The process which uses nylon 6, which is easier to depolymerise than nylon 6,6 starts with old carpet fibres. These are shredded, cleaned and melted down, and the resulting liquid is steam-extracted. After distillation, the extract yields virgin-grade caprolactam. The residue, of latex, calcium carbonate and polypropylene, can be used as a filler in roofing or concrete.
The partners are planning to build a 45 000 tpa plant based on this technology at DSM's site in Augusta, Georgia. Costing some $100 million, the plant is slated for start-up in 1999. It will use both carpet waste from nearby manufacturers and old, reclaimed carpets, the companies say. The US generates some 1.8 million tpa of carpet waste, of which 450 000 tpa is nylon 6, says DSM, so there should be no shortage of feedstocks.
As the process demands a specific feedstock, the companies working with LTIndustries have also developed a sensor device to check whether a carpet is indeed made of nylon 6. Based on infra-red spectroscopy, the device needs only be brushed across the surface of the fibres to give a reading.
