Seeking to boost the quality of recycled nylon 6/6, DuPont plans to launch a pilot plant next year to test a new, patented process.
The demonstration facility, opening in Maitland, Ontario, will help DuPont test the ammonolysis process, a chemical means of recycling nylon resin.
The process was developed in DuPont's research and development laboratories in Kingston, Ontario, during the past four years. The company has spent more than $15 million to prepare the technology for commercial use, said DuPont Automotive global account manager Clint Christian, based in Troy, Mich.
The work responds to the needs of automakers and carpet manufacturers for recycled material that can perform as well as the original resin, Christian said.
``It opens up DuPont to other opportunities,'' Christian said. ``It's a business decision that helps our customers avoid landfills. We can step in with significant recycling support.''
Yet, to date, Wilmington, Del.-based DuPont and other resin suppliers have not been able to provide adequate support to recycle nylon 6/6 chemically. The process, breaking nylon down to its fundamental building blocks, allows the resin to be reused in similar applications.
The company has tried mechanical recycling to separate the material, but that process is time-consuming and leaves resin that is not pure enough for some complex applications, Christian said.
DuPont simultaneously has worked to perfect its chemical processes, involving reactors more than human labor, said Diane Richard, technology manager at the supplier's Kingston research facility.
The ammonolysis process breaks nylon 6/6 back to its molecular form, converting the refined resin to hexamethalene diamene. In that stage, the material can be repolymerized, compounded or blended with virgin resin to produce a high-performing material, Richard said.
The Maitland pilot plant, scheduled to open in the second half of next year, will allow DuPont to recycle higher volumes of nylon than can be obtained in a lab environment. Instead of 5-10 pounds per hour processed in the lab, the new facility can reprocess about 2 millions pounds a year, Richard said.
The Maitland facility, on the grounds of an existing DuPont processing center for nylon monomers, will include a reactor running on a continuous basis. The square footage of the facility still must be determined, Richard said.
Once DuPont proves the technology, the next step will be a major commercial facility. That facility, producing 10-20 times the amount of recycled nylon made at the Maitland plant, could be launched by 2002, Richard said.
The ammonolysis process also can break down nylon 6 resin without having to separate it from nylon 6/6, Christian said. However, DuPont does most of its work in nylon 6/6.
DuPont makes about 1.3 billion pounds of nylon worldwide, Richard said. The company collects nylon-backed carpet at 75-80 collection sites, Christian added.
The company also is working on an alternative chemical recycling process in case ammonolysis does not prove viable, Richard said. She declined to give details until the process is developed further.
DuPont is not alone in pursuing chemical recycling for nylon. Two other resin suppliers, AlliedSignal Inc. of Morristown, N.J., and DSM Chemicals North America Inc. of Augusta, Ga., have formed a joint venture to recycle nylon 6 resin. The venture, called Evergreen Recycling LLC, will recycle the resin chemically and produce caprolactam, a nylon 6 monomer. The monomer will be split evenly between the companies.
``The caprolactam will be identical to that from conventional sources,'' said Ed Duffy, manager of recycling technology at AlliedSignal's technical center in Petersburg, Va. ``Sooner or later, we'll need additional caprolactam to grow. This allows us to grow in an environmental manner.''
The companies plan to open a 40,000-square-foot plant in Augusta by late September at a cost of about $80 million, said David Mezzanotte, Evergreen general manager. A pilot facility has operated for more than year in Petersburg.
``A huge driver is the automotive industry,'' Mezzanotte said. ``Carmakers have set very aggressive corporate goals to add recycled content to vehicles. The limitation has been the lack of chemical recycling.''
The nylon recycling work is overdue, for a material first introduced in the early 1940s, DuPont's Richard said. DuPont actually took out its first patent to break down nylon 6/6 in 1946, she added.
``There's been more concern about environmental stewardship and sustainability since 1989,'' she said. ``But until now, there's never been anything potentially economically viable for a long-term solution.''
A case in point was a high-profile program launched in January 1997 with parts supplier Visteon Automotive Systems of Dearborn, Mich.
DuPont mechanically separated and reground nylon for Visteon's air-cleaner housings.
However, with economic burdens pressing DuPont, Visteon transferred the work to Wellman Inc. of Shrewsbury, N.J., a year later.