| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an aliphatic polyester of improved yield compared with conventional method for polymerizing an aliphatic polyester. SOLUTION: An aliphatic polyester having a weight-average molecular weight of 100,000-600,000 and containing 0-2 wt.% aliphatic cyclic ester is produced by carrying out a ring-opening polymerization of an aliphatic cyclic ester (a) in molten state to obtain an aliphatic polyester (b) having a weight-average molecular weight of 100,000-600,000 and containing 20-70 wt.% aliphatic cyclic ester, granulating the product and bringing the granule into contact with an organic solvent in a state not to dissolve the aliphatic polyester. In the above method, the aliphatic cyclic ester present in the organic solvent after the contact with the aliphatic polyester is purified and the obtained aliphatic cyclic ester is used again as the polymerization raw material. COPYRIGHT: (C)2008,JPO&INPIT
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