PROCESS TO PREPARE HIGH HEAT POLYCARBONATES

摘要

A catalyzed interfacial phosgenation process with controlled feed ratios and controlled reaction pH levels allows for the formation of high heat polycarbonate random copolymers having high loadings of bis (4-hydroxyphenyl)-2-phenylisoindolin-1-one (“PPPBP”) or a structurally related comonomer. The process produces a polycarbonate copolymer having improved hydrolytic stability.

主权项

1. A method for preparing polycarbonate copolymer by an interfacial method, comprising
phosgenating a mixture comprising an aromatic dihydroxy compound, water, an organic solvent substantially immiscible with water, and a condensation catalyst to form a reaction mixture; cofeeding an aqueous high heat comonomer feed to the reaction mixture during the phosgenation step at a ratio of about 1.75 to about 9 high heat comonomer/phosgene weight/weight dry basis; and maintaining the pH of the reaction mixture during the phosgenation step at greater than 7 to less than 11, to form a polycarbonate copolymer comprising greater than about 30 mole % structural units derived from the high heat comonomer.