Method for the manufacture of caprolactam from waste containing polyamides

US7173127B2 · kind B2 · utility

Assignee

• Zimmer, Inc. · US

Inventors

• Claus Born · Ingelheim am Rhein, DE
• Rudolf K{hacek over (a)}mpf · Ortenburg, DE
• Joachim Seelig · Bad Orb, DE
• Reinhard Wolf · Isny im Allgäu, DE

Key dates

• Filing date: Jun 9, 2003
• Grant date: Feb 6, 2007
• Expiry date: Dec 25, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D201/12
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

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.