Method of stabilization of dihydric phenols

US7521505B2 · kind B2 · utility

Assignee

• Sabic Innovative Plastics B.V. · NL

Inventors

• Venugopal Boddapaty Venkata · Bengaluru, IN
• Gurram Kishan · Bengaluru, IN
• Jan-Pleun Lens · Breda, NL
• Daniel Francis Lowery · Mount Vernon, US
• Mahesh Malusare · Bengaluru, IN
• Patrick Joseph McCloskey · Watervliet, US
• Manisha Potdar · Bengaluru, IN

Key dates

• Filing date: Jun 12, 2006
• Grant date: Apr 21, 2009
• Expiry date: Aug 28, 2027

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G64/307
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

A method of producing a polycarbonate, the method comprising:polymerizing a dihydric phenol and a carbonate precursor in the presence of oxalic acid to produce a polycarbonate with a yellowness index of less than or equal to 10 measured in accordance with ASTM E313 test method on molded samples having a thickness of about 2.5 millimeters;wherein the amount of oxalic acid ranges from about 20 parts per million to about 350 parts per million, relative to an amount of the dihydric phenol; wherein the dihydric phenol is represented by Formula (I):wherein R is a hydrogen atom or an aliphatic functionality having 1 to 6 carbon atoms; and n is an integer having a value of 1 to 4.