Aromatic polyester-polycarbonate

Claim 1

An aromatic polyester-polycarbonate resin having a glass transition point ranging from 160° C. to 190° C. and having a terminal carboxyl group content of not more than 10μ equivalents/g of resin, comprising: a polymer material composed of repeating units of structures I-III: ##STR4## wherein X is a divalent organic radical and the divalent aromatic entities in structures in I, II and III may be substituted by hydrocarbon substituents and wherein the molar proportion of dihydroxy-diaryl units to benzene dicarboxylic acid units to carbonate units ranges from 1:0.33-0.75:0.67-0.25 with the molar ratio of the terephthalic acid units to isophthalic acid units of said benzene dicarboxylic acid units ranging from 9:1 to 2:8, said terephthalic acid units and said isophthalic acid units being formed in said polymer material by the presence of a terephthaloyl chloride compound selected from the group consisting of terephthaloyl chloride, methyl terephthaloyl chloride and 2,5-dimethyl terephthaloyl chloride and an isophthaloyl chloride compound selected from the goup consisting of isophthaloyl chloride and 2-methylisophthaloyl chloride in the reacting monomers which form said polymer material.

Claim 7

A method of preparting an aromatic polyester-polycarbonate resin, comprising: polycondensing a dihydroxy-diaryl compound in an aqueous alkaline solution with a combination of a terephthaloyl chloride compound and an isophthaloyl chloride compound in an organic solvent thereby forming a low molecular weight polyester oligomer having terminal OH groups; reacting said oligomer with phosgene thereby converting said terminal OH groups into terminal OCOCl groups; condensing the product of reaction between said oligomer and said phosgene with a dihydroxy-diaryl compound in an aqueous alkaline solution; and separating the product polyester-polycarbonate resin from said reaction medium.

Claim 8

A method of preparting an aromatic polyester-polycarbonate resin, comprising: polycondensing a dihydroxy-diaryl compound in an aqueous alkaline solution with a combination of a terephthaloyl chloride compound and an isophthaloyl chloride compound in an organic solvent thereby forming a low molecular weight polyester oligomer having terminal OH groups; reacting said oligomer with phosgene thereby converting said terminal OH groups into terminal OCOCl groups; condensing the product of reaction between said oligomer and said phosgene with a dihydroxy-diaryl compound in an aqueous alkaline solution; and separating the product polyester-polycarbonate resin from said reaction medium.