| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for simply producing a high-molecular weight aliphatic polyester substitutable for a general purpose resin required to have toughness in a high volume efficiency by subjecting inexpensive raw materials, e.g. an aliphatic hydroxycarboxylic acid such as lactic acid, glycolic acid, etc., an aliphatic polyhydric alcohol such as butanediol, etc., and an aliphatic polybasic acid such succinic acid, etc., to condensation polymerization to give a prepolymer being a readily obtainable low-molecular weight aliphatic polyester as a starting raw material, crystallizing the prepolymer and subjecting the prepolymer to condensation polymerization in the presence of a catalyst in a solid phase. SOLUTION: This method for producing the aliphatic polyester having 50,000 to 1,000,000 weight-average molecular weight, containing >=50% of an aliphatic hydroxycarboxylic acid unit comprises subjecting a crystallized aliphatic polyester prepolymer having 20,000 to 100,000 weight-average molecular weight, containing >=50% aliphatic hydroxycarboxylic acid unit to solid-phase polymerization in the presence of a catalyst.
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