Patent ID: 6657038
Filing Date: 2003-12-02
Classification: C08G

Abstract:
A method of preparing a copolycarbonate said method comprising contacting under melt polymerization conditions at least one first dihydroxy aromatic compound, and at least one second dihydroxy aromatic compound, with at least one diary carbonate having structure I wherein R1 is independently at each occurrence a halogen atom, nitro group, cyano group, C1-C20 alkyl group, C4-C20cycloalkyl group, or C6-C20 aryl group; and p and q are independently integers 0-5; and at least one melt polymerization catalyst, said catalyst comprising at least one metal hydroxide and at least one quaternary phosphonium salt having structure II wherein R2-R5 are independently a C1-C20 aliphatic radical, C4-C20cycloaliphatic radical or a C4-C20 aromatic radical, and Xâˆ’ is an organic or inorganic anion; said first dihydroxy aromatic compound having a boiling point at atmospheric pressure, said boiling point being less than about 340Â° C.