	US 7,538,143 B2
	Method for the treatment of waste containing polyamide with the reprocessing of the depolymerisation residue
Rudolf Kämpf, Haingründau (Germany); Reinhard Wolf, Rodenbach (Germany); and Joachim Seelig, Biebergemund (Germany)
Assigned to Zimmer Aktiengesellschaft, Frankfurt am Main (Germany)
Filed on Jul. 23, 2004, as Appl. No. 10/897,473.
Claims priority of application No. 103 33 538 (DE), filed on Jul. 23, 2003.
Prior Publication US 2005/0054739 A1, Mar. 10, 2005
This patent is subject to a terminal disclaimer.
Int. Cl. C08J 11/04 (2006.01)

U.S. Cl. 521—40 [540/540; 521/49; 521/49.5; 521/49.8]

23 Claims

1. Method for the treatment of waste containing polyamide, comprising

a) depolymerisation of the waste containing polyamide in a depolymerization reactor, whereby a caprolactam raw material and a flow, comprising secondary constituents and additives from the depolymerisation, are obtained, the flow leaving the reactor separately from the caprolactam raw material, and

b) leaching of the flow separated in step (a) at east once using an extracting agent to form a slurry, wherein one or more of the secondary constituents selected from the group consisting of a cracking acid, a cracking alkali, 6-amino caproic acid, a cyclical polyamide oligomer and a linear polyamide oligomers is dissolved in the extracting agent, and wherein the extracting agent comprises at least one of water, an alcohol, an alkyl carbonate, or an amine.