| 摘要 |
PURPOSE:To obtain an unsaturated polyester resin which has a shortened esterification time without detriment to the storage stability of the resin, by esterifying an unsaturated dibasic acid with a polyalcohol by using a specified phosphorus compound as a catalyst. CONSTITUTION:The purpose unsaturated polyester resin is obtained by esterifying an unsaturated dibasic acid with a polyalcohol by using a phosphorus compound of the formula as an esterification catalyst. In the formula, R is C2H5O-, ClCH2CH2O-, C4H9-O-C2H4 or C8H17O- and n is 1-2. The amount of the phosphorus compound of the formula added in performing the esterification is preferably 0.001-0.5wt% based on the unsaturated polyester to be produced. Examples of the phosphorus compounds used include ethyl acid phosphate and butoxy acid phosphate.
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