Bayer Materialscience Ag

Dirk Van Meirvenne

Thomas König

Klemens Kohlgrüber

Jörg Kirchhoff

Steffen Kühling

Johan Vanden Eynde

Melanie Möthrath

Johan Vaes

René De Cleyn

The invention relates to an apparatus and a process for devolatilizing solvent-containing polycarbonate solutions. By employing the inventive apparatus, polycarbonates with low residual values of volatile constituents are produced from solvent-containing polymer melts, which improved optical properties, especially yellowness index, with the aid of an apparatus combination of a heatable tubular devolatilizer and a vented extruder.

Device and method for degassing solvent-containing polycarbonate solutions

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&#xb0; to 340&#xb0; 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.

Process for the production of polycarbonate

The invention describes a process for the preparation of polycarbonate. The process includes

Process for the preparation of polycarbonate

Growing community of inventors

Krefeld, Germany

Dirk Van Meirvenne