摘要 |
An improved hydroxyl functional urethane-extended polyester is based on the condensation reaction of fumaric acid, one or more non-aromatic polyols, azelaic acid and optionally one or more non-aromatic carboxylic acids including lauric acid or stearic acid. The hydroxylated polyester urethane oligomer possesses a molecular weight below 2600 and a mole ratio of hydroxyl groups to urethane linkage of from 0.5 to 6. Gel coats prepared from these oligomers exhibit superior water resistance and improved weathering characteristics.
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