Method of producing polycarbonates

US6835798B1 · kind B1 · utility

Assignees

• BAYER HEALTHCARE LLC · DE
• Bayer Antwerpen N.V. · BE

Inventors

• Michael Bödiger · Dormagen, DE
• Steffen Kuhling · Meerbusch, DE
• Franky Bruynseels · Sint-Gillis-Waas, BE
• Dirk Van Meirvenne · Bang Phra, TH
• René de Cleyn · Brasschaat, BE

Key dates

• Filing date: Aug 5, 2002
• Grant date: Dec 28, 2004
• Expiry date: Mar 9, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G11B7/2534
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the preparation of polycarbonate by the phase boundary process is disclosed. The process entails reacting at least one dihydroxydiarylalkane in the form of its alkali metal salts with phosgene in the heterogeneous phase in the presence of sodium hydroxide solution and an organic solvent. The process is characterized in that the feedstock have but low content of Fe, Cr, Ni, Zn, Ca, Mg, Al metals or homologues thereof, and in that the organic solvent is separated off, and in that the polycarbonate which is obtained is worked up. The resulting polycarbonate is particularly useful in producing transparent shaped articles.