Process for the production of polycarbonate

US7129315B2 · kind B2 · utility

Assignee

• Bayer MaterialScience AG · DE

Inventors

• Jörg Kirchhoff
• Thomas König · Nuremberg, DE
• Klemens Kohlgrüber · Lingen (Ems), DE
• Steffen Kuhling · Meerbusch, DE
• Dirk Meirvenne · Krefeld, DE

Key dates

• Filing date: Apr 14, 2005
• Grant date: Oct 31, 2006
• Expiry date: Apr 14, 2025

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G64/205
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the isolation of polycarbonate produced by the interfacial polymerization process is disclosed. Accordingly, the process entails (a) evaporating the organic solvent from the solution that contains solvent and polycarbonate to obtain a material system that contains 90 to 99.95% polycarbonate, the percent being relative to the weight of the system, and (b) passing the material system through inlet openings of a separating vessel to obtain a plurality of streams of polycarbonate, on entry into the inlet openings said material system being supersaturated with volatile constituents to an extent of at least 1 bar and having a temperature of 250° to 340° C. and a flow rate of 0.1 to 20 kg/hour, and (c) degassing the streams in the separating vessel wherein the pressure is 0.1 to 20 mbar to effect degassing of the polycarbonate.