Polycarbonates with a low yellowness index

US6395864B1 · kind B1 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Steffen Kuhling · Meerbusch, DE
• Rolf Lanze · Krefeld, DE
• Michael Prein · Brasschaat, BE
• Rainer Neumann · Krefeld, DE
• Hermann Kauth · Krefeld, DE
• Christian Kords · Krefeld, DE
• Frieder Heydenreich · Düsseldorf, DE
• Tony van Osselaer · Krefeld, DE
• Wilfried Haese · Rheydt, DE

Key dates

• Filing date: Jun 20, 2001
• Grant date: May 28, 2002
• Expiry date: Jun 20, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31507
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A process for the preparation of polycarbonate resins having a low yellowness index is described. The process involves converting phosgene with a sodium bisphenolate solution by means of a phase interface process performed with the exclusion of oxygen. The sodium bisphenolate solution used in the process has a dissolved oxygen content of <150 ppb. Also described are optical data storage media prepared from the polycarbonate of the present invention.