| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester resin that is produced by using a titanium compound having excellent environmental stability as a catalyst for the polycondensation reaction and having a property that the catalyst is deactivated with heat treatment in water thereby the molten resin heat stability is enhanced, further the increase of cyclic oligomers can be suppressed after molding, thus mold stain is reduced on the molding. SOLUTION: Aromatic dicarboxylic acid and ethylene glycol, as main components, are polymerized in the presence of a catalyst of a titanium compound in an amount of 0.002 to 1.0 mol per 1 ton of polyester resin (the catalyst is calculated as Ti atom) to produce the polyester of this invention. This polyester resin satisfies the followed formula: (η<SB>3</SB>-η<SB>1</SB>)/(η<SB>2</SB>-η<SB>1</SB>)<0.90, whereinη<SB>1</SB>is the intrinsic viscosity of the polyester,η<SB>2</SB>is the intrinsic viscosity of the polyester obtained by heat-treating the produced polyester resin at 210°C for 10 hours under the nitrogen gas flow, andη<SB>3</SB>is the intrinsic viscosity of the polyester resin obtained by heat-treating the virgin polyester of an intrinsic viscosity ofη<SB>1</SB>in water at 95°C for 4 hours, additionally heat-treating the resultant polyester resin at 210°C for 10 hours under the nitrogen gas flow. COPYRIGHT: (C)2006,JPO&NCIPI
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