| 摘要 |
A process for the preparation of a water-soluble alkyd resin comprises reacting at a temperature of from 160 to 260 DEG C. a polycarboxylic acid or anhydride thereof with an ester of an aliphatic monocarboxylic acid containing at least two free hydroxyl groups or at least one epoxy group on the alcoholic part of the molecule, the carboxyl group in the monocarboxylic acid being attached directly to a tertiary or quaternary carbon atom; characterised in that at least 30% of the actual and potential carboxyl groups included in the reaction mixture form part of at least tribasic carboxylic acids or anhydrast thereof, and in that the total number of molecules of hydroxyl, carboxyl, epoxy and/or ester compounds in the reaction mixture together with the number of molecules of carboxyl compounds that could be formed by hydrolysis of potential carboxyl groups present is 0.9 to 1.5 times as large as the total number of actual and potential carboxyl groups, and in that the reaction is interrupted when the acid number has fallen to a value between 100 and 20. Polyhydroxy compounds and mono- and di-carboxylic acids may also be present in the reaction mixture. The examples disclose the preparation of alkyds from glycidyl esters of branched monocarboxylic acids (C9-C11)and:- (I) pyromellitic acid, glycerol and methylene glycol; (II) and (III) trimellitic anhydride, adipic acid and propylene glycol and (IV) and (V) pyromellitic acid, dipropylene glycol and glycerol. |
