| 摘要 |
PROBLEM TO BE SOLVED: To obtain polybutylene terephthalate excellent in quality and capable of being used in various kinds of uses as fiber, film and injection molded products by conducting esterification reaction and polycondensation reaction of 1,4-butylene glycol containing 2-(4'-hydroxybutoxy)tetrahydrofuran and terephthalic acid containing acetic acid as raw materials by a direct polymerization method. SOLUTION: By conducting esterification reaction and polycondensation reaction of a glycol comprising 1,4-butylene glycol as a principal ingredient and 0.05 to 0.5 wt.% 2-(4'-hydroxybutoxy)tetrahydrofuran and a dicarboxylic acid comprising terephthalic acid as a principal ingredient and 0.003 to 0.2 wt.% acetic acid, polybutylene terephthalate is obtained. The esterification reaction is conducted preferably at a reaction temperature of 180 to 250 deg.C, a pressure of 100 to 600 mmHg and a polybutylene terephthalate oligomer conversion of >=97%.
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