| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing polyester with improved hue and polymerizability by suppressing side reactions in polycondensation reaction. SOLUTION: The invention relates to the method for producing polyester comprising (A) an esterification step or a transesterificationuse step of a dicarboxylic acid or a dicarboxylic acid dialkyl ester and a diol as the main starting materials to obtain oligomers and (B) polycondensation to obtain the polymer by a continuous polycondensation reaction of the oligomers in molten state obtained in the reaction step (A), by using a plurality of reaction vessels, wherein the oligomers with≥90% of esterification rate or transesterification rate is obtained in the reaction step (A) and at least a horizontal reaction vessel having an axis of rotation of stirring blade in horizontal direction is used and the temperature of the contents at the entrance of the horizontal reaction vessel T1(°C) and the temperature of the contents at the exit T2(°C) satisfies inequality (1), T1>T2 --(1), in the polycondensation reaction step (B). COPYRIGHT: (C)2005,JPO&NCIPI
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