Process for the splitting of polycarbonates

US5266716A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hans-Josef Buysch · Krefeld, DE
• Norbert Schon · Krefeld, DE
• Steffen Kuhling · Meerbusch, DE

Key dates

• Filing date: Dec 9, 1992
• Grant date: Nov 30, 1993
• Expiry date: Dec 9, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G64/42
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the continuous splitting of polycarbonates into dihydroxy compounds and carbonic acid esters is disclosed. Accordingly there are reacted in a distillation column a polycarbonate resin and a monohydroxy compound in the presence of a transesterification catalyst. The polycarbonate, in molten form or as a solute, is continuously fed into the upper part of the column and the monohydroxy compound in vapor phase is continuously fed into the lower part of the column. The resulting carbonic acid ester and dihydroxy compounds are continuously being removed from the column. The process is eminently suitable for the recycling of polycarbonate waste.