| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for industrially advantageously producing in the presence of a low-cost iron-based catalyst a high molecular weight aliphatic polyester-based polymer having a practically sufficient molecular weight and excellent in mechanical strength, and to provide the same polymer obtained by the method. SOLUTION: In polycondensation reaction using (i) a mixture of an aliphatic dicarboxylic acid (or its diester) with an aliphatic diol or (ii) a precondensate obtained from the mixture as a reaction raw material in the presence of a transesterification catalyst comprising an iron-based catalyst or the iron-based catalyst and a co-catalyst, this method for producing the aliphatic polyester- based polymer comprises using at least one protonic acid or its ester selected from the group consisting of an organic phosphonic acid represented by general formula (1) O=P(OH)2R or O=P(OH)R2 (R is an aliphatic group or an aromatic group), a silicate represented by formula (2) (RO)2SiR2 (R is an aliphatic group or an aromatic group), phosphoric acid, ammonium phosphate, an aliphatic and/or aromatic compound having sulfonate group or sulfate group and sulfuric acid as the co-catalyst.
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