PURPOSE: To produce the title copolymer excellent in melt flow during molding and also in mechanical properties, heat resistance and transparency, by melt- mixing as alkylene terephthalate oligomer with a carbonate oligomer and polycondensing the mixture while removing a volatile compound therefrom.
CONSTITUTION: 20W80wt.% alkylene terephthalate oligomer (A) mainly consisting of ethylene terephthalate units and having an intrinsic viscosity ≤0.6dl/g as measured in o-chlorophenol at 25°C is mixed with 20W80wt.% carbonate oligomer (B) mainly consisting of 2,2-bis(4-hydroxyphenyl)propane and having an intrinsic viscosity ≤0.6dl/g, and the resulting mixture is melt-mixed and polycondensed while the formed volatile matter is removed in a vacuum to produce the title transparent monomodal copolymer having an intrinsic viscosity of 0.4W1.2dl/g, a glass transition temperature Tg of 80W140°C.
AZUMA ISABURO
AKANA YOSHINORI
