Preparation of copolycarbonates

US6753405B2 · kind B2 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Silke Kratschmer · Krefeld, DE
• Lothar Bunzel · Kempen, DE
• Hans Deml · Krefeld, DE

Key dates

• Filing date: Jul 12, 2002
• Grant date: Jun 22, 2004
• Expiry date: Jul 12, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G64/307
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the preparation of transparent copolycarbonate is disclosed. The copolycarbonate the molecular structure of which contains more than 35 mole % of units derived from dihydroxydiphenylene is prepared by the melt transesterification process wherein the final temperature of the reaction is reached in less than 40 minutes after reaching the starting temperature.