| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing process of polyethylene terephthalate by direct polymerization by which the problem of fluctuation in COOH end groups caused by fluctuation in the esterification ratio is solved and a polymer with a stable color is obtained. SOLUTION: The manufacturing process of polyethylene terephthalate comprises measuring the color (b value) of the product polymer and adjusting the revolution of the agitator of the polycondensation reaction vessel producing low molecular polymers with an average degree of polymerization of 20-80 depending on the deviation of the measured value from the target value in the course of manufacturing the polyethylene terephthalate by continuously esterifying and polycondensing terephthalic acid and ethylene glycol. COPYRIGHT: (C)2006,JPO&NCIPI
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