| 摘要 |
A low molecular weight polyester resin is made by condensation reaction of particular polyols and carboxylic acids in a reaction mixture having excess hydroxyls and a system functionality between about 1.6 and 1.8. In one embodiment, an aliphatic diol, a cyclic dicarboxylic acid and a monobasic fatty acid are condensation reacted together to produce the polyester resin, whereas in a second, and preferred, embodiment, the monobasic fatty acid is present as a hydroxyl-bearing, polyol-esterified oil or fatty acid. The polyester resin of either embodiment can be cross-linked with an aminoplast resin, in the presence or absence of pigment, in a coating composition comprising 90% by weight and higher amounts of solids to produce cured coatings exhibiting good hardness, flexibility, chemical resistance and gloss. Pigment can be present in the cured coatings in amounts up to at least 60% by weight of the solids. |
