| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a polyester which has excellent molding processability and can solve problems such as the staining of a spinneret, the elevation of filtration pressure and the breakage of fibers on the production of formed products such as fibers, films or bottles. SOLUTION: This method for producing a polyester comprises subjecting an aromatic dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative to an esterification reaction or a transesterification reaction and then polycondensing the product. Therein, the characteristics comprise using a dinuclear oxide containing titanium and silicon as main metal elements as a polycondensation catalyst and controlling the molar ratio (the molar ratio of the aromatic dicarboxylic acid or its ester-forming derivative to the diol or its ester-forming derivative) of the reaction system to 1.25 to 2.0 when the dinuclear oxide is added.
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