| 摘要 |
PROBLEM TO BE SOLVED: To obtain such a polyester as to reduce stains of a treatment tank and/or piping involved in water treatment of polyester chips and be capable of giving molded products with slight residual offensive taste and/or odor from the chips. SOLUTION: A method for producing a polyester comprises conducting a water treatment of polyester chips by feeding them and treatment water into a treatment tank; wherein while maintaining the respective contents of the corresponding glycol derived from the polyester and monomers comprising the corresponding aromatic dicarboxylic acid and glycol in the treatment water discharged together with the polyester chips from the treatment tank at <=100 ppm, at least part of the treatment water discharged from the treatment tank is returned to the treatment tank and used repeatedly.
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