| 摘要 |
PROBLEM TO BE SOLVED: To produce a polyester having high intrinsic viscosity suitable for direct blow molding, by obtaining a polymer from a specific acid component and a diol component by melt condensation polymerization and subjecting the polymer to solid-phase polymerization while maintaining the water content of the polymer at a specific value or lower than it. SOLUTION: A carboxylic acid component consisting essentially of terephthalic acid or its ester forming derivative are a diol component consisting essentially of ethylene glycol (e.g. containing 0.5-10mol% of cyclohexanedimethanol and 1.0-4.0mol% diethylene glycol in the diol component, respectively) are esterified or transesterified to give a product, which is subjected to melt condensation polymerization to give a polymer having 0.45-0.8dL/g intrinsic viscosity (η). Then the polymer is subjected to solid polymerization while maintaining it at 200-225 deg.C for 15-35 hours in <=0.1wt.% water content to give the objective polyester having 1.0-2.0dL/gη, preferably 1.10-1.20dL/g and <=4.0ppm acetaldehyde content.
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