Closed-loop recycling

Mechanical Engineering, May 2002 by DeGaspari, John

DuPont says it has developed a new process that can recycle reinforced nylon and let it keep the same properties as the virgin material. As a demonstration, Denso Corp., an automotive systems supplier based in Ariya, Japan, recently produced a prototype radiator end tank made of 100 percent recycled, glass-reinforced nylon 66.

The material was reclaimed by Composite Recycle Technology, a recycling process developed by DuPont Engineering Polymers of Wilmington, Del., for nylon. DuPont claims that the process has the ability to make a part again from the same nylon, with the same physical properties as the original, said Jan Stouffer, the technology manager of Zytel nylon resins at DuPont.

According to Denso, some of the recycled nylon in its prototype was recovered from used end tanks.

Composite Recycle Technology is a chemical process that cleans the plastic of reinforcements and dirt, and, if there is the need, can recoup some of the molecular weight to build up the properties, said Stouffer. Another process, called ammonolysis, can restore more of the original molecular weight, but it is costlier than the new technology, she said.

DuPont says that the process can accept a variety of nylon polymers, including 6 and 66, as well as a range of reinforcements, such as glass and minerals. DuPont and Fielding Chemical Technologies Inc., a recycler of solvents and refrigerants, are jointly demonstrating the process at a site that Fielding operates in Mississauga, Ontario.