Patent ID: 6812320
Filing Date: 2004-11-02
Classification: C08G

Abstract:
A method for preparing a block copolyestercarbonate comprising chain members derived from at least one dihydroxy-substituted aromatic hydrocarbon moiety and at least one aromatic dicarboxylic acid moiety, said polymer being substantially free of anhydride linkages linking at least two mers of the polyester chain segments, comprising the steps of:(a) preparing a hydroxy-terminated polyester intermediate comprising structural units derived from at least one dihydroxy-substituted aromatic hydrocarbon moiety and at least one aromatic dicarboxylic arid moiety; and (b) conducting a reaction of the polyester intermediate with phosgene in a reaction mixture comprising water, a substantially water-immiscible organic solvent, and a base, wherein base and phosgene are added simultaneously to the reaction mixture at a substantially constant molar ratio of base to phosgene for a time period of at least about 60% of the total amount of phosgene added.