| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester polyol capable of reducing the content of free or unreacted dihydroxycarboxylic acid even by using a dihydroxycarboxylic acid (e.g. dimethylol alkanoic acid such as dimethylol propionic acid) as an initiator. SOLUTION: Ring-opening addition polymerization of a cyclic ester (e.g. lactones such asε-caprolactone) to a dihydroxycarboxylic acid is carried out in the presence of a basic compound (e.g. amines). At least a part of carboxyl group constituting the polyester polyol produced by the method forms a salt with the basic compound to remarkably reduce the content of free dihydroxycarboxylic acid (e.g. to≤5 wt.% of the total polyester polyol). COPYRIGHT: (C)2008,JPO&INPIT
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