摘要 |
Water-dilutable polyurethane resins with acid groups, wherein the polyurethane resins contain units derived from oils A which are at least partly unsaturated, from olefinically unsaturated aliphatic acids B or anhydrides B' thereof, from compounds C having functional groups which are reactive towards acid groups or acid anhydride groups, selected from the group consisting of epoxide groups, hydroxyl groups, mercaptan groups and amino groups, and which react in the reaction with the compounds B or B' to form an ester group, a thioester group or an acid amide group, where the compounds C are selected from the group consisting of compounds C'' which additionally contain sulfonic acid groups, or carboxylic acid groups which are activated by electron-withdrawing substituents, and compounds C' which additionally contain at least one hydroxyl group which is retained during the reaction with the compounds B or B', and where at least a mass fraction of 25% of the compounds C consists of compounds C'', and polyfunctional isocyanates D, a process for their preparation, their use as catalysts in the curing of binders containing hydroxyl groups with aminoplast resins, and stoving paints which contain these catalysts
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