Branched melt polycarbonate with low content of defective structures

US8487025B2 · kind B2 · utility

Assignee

• Bayer MaterialScience AG · DE

Inventors

• Stephan Konrad · Dormagen, DE
• Helmut-Werner Heuer · Krefeld, DE
• Karl-Heinz Köhler · Aachen, DE
• Christian Münnich · Leverkusen, DE
• Rolf Wehrmann · Krefeld, DE

Key dates

• Filing date: Apr 7, 2011
• Grant date: Jul 16, 2013
• Expiry date: Jan 4, 2032

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08K5/49
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention relates to an aromatic branched polycarbonate, produced via melt transesterification of a bisphenol with a diaryl carbonate in the presence of a branching agent, wherein the aromatic branched polycarbonate comprises branching point structures and structures of formula (D)wherein X is a single bond, C1- to C6-alkylene, C2- to C5-alkylidene or C5- to C6-cycloalkylidene, optionally substituted by C1- to C6-alkyl; wherein the amount of D in the aromatic branched polycarbonate is in the range of from 5 to 450 mg per kg of the aromatic branched polycarbonate; and wherein the ratio of the total branching point structures to the total structures of the formula D in the aromatic branched polycarbonate is in the range of from 8 to 200.