Method for copolyestercarbonate synthesis

An interfacial method for preparing a block copolyestercarbonate comprising polyester block segments with chain members derived from a mixture of terephthaloyl dichloride and isophthaloyl dichloride in a molar ratio in a range of about 0.4-2.5:1 and unsubstituted resorcinol, and polycarbonate segments with chain members derived from at least one of unsubstituted resorcinol and bisphenol A;

• wherein said copolyestercarbonate is substantially free of anhydride linkages linking at least two mers of the polyester blocks, comprising the steps of:
• (a) preparing a hydroxy-terminated polyester intermediate having a degree of polymerization of at least 4;
• and
• (b) conducting a reaction of the polyester intermediate with phosgene in a reaction mixture comprising water, dichloromethane, at least one catalyst, 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.

An interfacial method for preparing a block copolyestercarbonate comprising polyester block segments with chain members derived from a mixture of terephthaloyl dichloride and isophthaloyl dichloride in a molar ratio in a range of about 0.4-2.5:1 and unsubstituted resorcinol, and polycarbonate segments with chain members derived from at least one of unsubstituted resorcinol and bisphenol A;

• wherein said copolyestercarbonate is substantially free of anhydride linkages linking at least two mers of the polyester blocks, comprising the steps of:
• (a) combining at least one 1,3-dihydroxybenzene moiety and at least one catalyst in a mixture of water and at least one organic solvent substantially immiscible with water;
• (b) adding to the mixture from (a) a controlled stoichiometric ratio of at least one acid chloride and at least one base while maintaining the pH between about 5 and about 8.5, and
• (c) adjusting the pH of the reaction mixture to a value in the range of about 7 and about 9 following complete addition of acid chloride, and stirring the reaction mixture for a time sufficient to destroy any anhydride linkages in the polymer chain, thus preparing a polyester intermediate;
• and
• (d) conducting a reaction of the polyester intermediate with phosgene in a reaction mixture comprising water, dichloromethane, at least one catalyst, and a base, wherein base and phosgene are added simultaneously to the reaction mixture at a substantially constant molar ratio of base to phosgene in a range of between about 1.8 and about 2.5 mole base per mole phosgene during the addition process.

A method for preparing a block copolyestercarbonate substantially free of anhydride linkages linking at least two mers of the polymer chain, which comprises the steps of:

• (a) preparing a hydroxy-terminated polyester intermediate in a molten reaction mixture comprising at least one 1,3-dihydroxybenzene moiety and at least one aromatic dicarboxylic acid diarylester under transesterification conditions, said polyester intermediate having a degree of polymerization of at least 4;
• recovering the copolyestercarbonate from the reaction mixture;
• and
• (b) conducting a reaction of the polyester intermediate with phosgene in a reaction mixture comprising water, dichloromethane, at least one catalyst, and a base, wherein base and phosgene are added simultaneously to the reaction mixture at a substantially constant molar ratio of base to phosgene.