Patent ID: 6350846
Filing Date: 2002-02-26
Classification: C08G

Abstract:
A method for preparing copolycarbonates by solid state polymerization comprising:step (A) combining in the molten state a homopolycarbonate derived from a dihydric phenol having structure I wherein R1 and R2 are independently fluorine, chlorine, bromine, aliphatic, cycloaliphatic or aromatic radicals, n and m are integers having values of 0 to 4, and W is an aliphatic radical, a cycloaliphatic radical an aromatic radical, or an oxygen, sulfur, SO or SO2 linking group, with an aliphatic diol carbonate having structure II wherein a is an integer from 2 to 100 and b is an integer from 1-200, together with a sufficient amount of diphenyl carbonate to crystallize the mixture upon cooling; step (B) cooling the mixture to ambient temperature to afford a crystalline mixture; and step (C) subjecting said mixture to solid state polymerization, whereby a copolycarbonate incorporating repeat units derived from structures I and II is obtained.