The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 06, 2007
Filed:
Jun. 09, 2003
Claus Born, Ingelheim, DE;
Rudolf K{hacek Over (A)}mpf, Gründau, DE;
Joachim Seelig, Biebergemünd, DE;
Reinhard Wolf, Rodenbach, DE;
Claus Born, Ingelheim, DE;
Rudolf K{hacek over (a)}mpf, Gründau, DE;
Joachim Seelig, Biebergemünd, DE;
Reinhard Wolf, Rodenbach, DE;
Zimmer Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
This invention relates to a continuous and efficient method for the manufacture of highly pure caprolactam suitable for the polycondensation of Polyamide 6 (polycaprolactam) from polyamide waste. In particular the invention relates to a method for the manufacture of caprolactam from waste containing polyamides, including the steps a) depolymerisation of the waste containing polyamides, whereby a caprolactam raw material and a flow containing secondary constituents or additives is obtained, b) at least one distillation of the caprolactam raw material, and c) at least one crystallisation of the caprolactam material obtained in step b), by which means caprolactam is obtained, whereby at least part of the caprolactam obtained in step c) with a permanganate number of<10000 sec. and a UV transmission of<85% is added to the waste containing polyamides before and/or during the depolymerisation.