Process for the preparation of epoxy resin based paint binders

1,126,820. Epoxy resin esters; unsaturated polyesters. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 20 Feb., 1967 [22 Feb., 1966], No. 7979/67. Headings C3B and C3P. A condensation product which is thinnable with water after neutralization and which contains free carboxyl groups is prepared by: (1) reacting a polyglycidyl ether of a polyhydric phenol with a saturated monocarboxylic acid in which the carboxyl group is bound to a tertiary or quaternary carbon atom in an amount of 0À5 to 1 acid equivalents per epoxide equivalent; (2) the hydroxyl group containing ester obtained in (1) is reacted with an ethylenically unsaturated fatty acid in an amount up to 1 acid equivalent of fatty acid per OH equivalent of the ester; and (3) reacting the resultant polyester with at least 4% by wt. of the polyester of an ethylenically unsaturated polycarboxylic acid or an anhydride thereof. The polyglycidyl ether may be derived from bisphenol A and have an epoxide equivalent of 170-600. The monocarboxylic acid in which the COOH group is attached to a tertiary or quaternary carbon atom may be obtained by reaction between an olefin and formic acid or carbon monoxide and water in the presence of a liquid inorganic acid catalyst. The acid may contain 8-18 carbon atoms. The ethylenically unsaturated acid may contain more than one ethylenic group per molecule (e.g. drying oil acids). In preparing a water thinnable binder for coating compositions at least 50% of the carboxyl groups are neutralized, e.g. with a primary, secondary or tertiary aliphatic or cycloaliphatic amine. A lyotropic solvent, e.g. ethyleneglycol monobutyl ether, may also be present. Conventional fillers and pigments may be present.