Patent ID: 7199212
Filing Date: 2007-04-03
Classification: C08G

Abstract:
1. A process for producing polyester, comprising adding a polyester polymerization catalyst comprising at least one kind selected from the group consisting of aluminum and compounds thereof as a first metal-containing component, characterized in that the thermal stability parameter (TS) of polyethylene terephthalate (PET) polymerized by the polyester polymerization catalyst satisfies the following formula (1): wherein TS is a numerical value calculated in the formula; from the final intrinsic viscosity ([IV] f ) which is determined after 1 g Pet having an initial intrinsic viscosity ([IV] i ) of approximately 0.65 dl/g is placed in a glass test tube, vacuum-dried at 130° C. for 12 hours, and maintained in a molten state at 300° C. for 2 hours in a non-circulating nitrogen atmosphere, the polyester one or more of polyvalent carboxylic acids including discarboxylic acids and ester-forming derivatives thereof and one or more of polyvalent alcohols including gylcols, or comprising one or more of hydroxycarboxylic acids and ester-forming derivatives thereof.