Aqueous polyesters, a process for their production and their use in high- solids stoving lacquers

摘要

The present invention relates to aqueous polyesters for high- solids stoving coatings which containPPa) 35.0 to 65.0% by weight of a polyester resin containing urethane, carboxyl and hydroxyl groups and containing the reaction product ofPP77 to 89% by weight of a branched polyester polyol having a hydroxyl number of 125 to 175, an acid number of less than 4 and a molecular weight of 2,500 to 6,500,PP2) 2.5 to 4.5% by weight of a 2,2-bis- (hydroxymethyl)alkane carboxylic acid,PP3) 0 to 3.5% by weight of a diol component having a molecular weight of 62 to 250 and PP4) 9 to 19% by weight of a diisocyanate component,P P wherein the percentages of a1), a2), a3) and a4) add up to 100%, based on the weight of a1), a2), a3) and a4),PPb) 0.1 to 1.5% by weight of a basic neutralizing agent which is sufficient to convert 35 to 100% of the carboxyl groups of component a) to carboxylate groups,PPc) 0 to 7.5% by weight of an organic auxiliary solvent andPPd) 26 to 64.9% by weight water,P Pwherein the percentages of a), b), c) and d) add up to 100%, based on the weight of a), b), c) and d).