Polyester carbonate copolymers processes for preparing same and polyester resin compositions containing said copolymers.

摘要

In accordance with the present invention, there are provided polyester carbonate copolymers obtained by polymerization of a mixture of 20-80% by weight of an alkylene terephthalate oligomer [I] containing ethylene terephthalate as main structural units and having an intrinsic viscosity [ eta ], as measured at 25<o>C in o-chlorophenol, of less than 0.6 dl/g, and 20-80% by weight of a carbonate oligomer [II] containing 2,2-bis(4-hydroxyphenyl)propane as main structural units and having an intrinsic viscosity [ eta ], as measured at 25<o>C in o-chlorophenol, of less than 0.6 dl/g, said copolymers having an intrinsic viscosity [ eta ], as measured at 25<o>C in o-chlorophenol, of 0.4-1.2 dl/g and a glass transition temperature (Tg) of 80-140<o>C with a single peak, and polyester resin compositions containing said copolymers, said resin composition being excellent in transparency, heat resistance and mechanical strength.