摘要 |
Synthetic resins suitable for use in the preparation of baking varnishes are prepared by copolymerizing a vinyl aromatic hydrocarbon, an ester of an alpha, beta-unsaturated monocarboxylic such as an acrylate and an alpha, beta-unsaturated, dicarboxylic acid, such as maleic acid, in solution or dispersion, the carboxyl groups of which being esterified with alcohols, etc. to yield a half-ester copolymer and reacted with alkylene oxides to a low residual acid number after which the solution or dispersion is adjusted with regard to acid number through the addition of phosphoric acid. |