Process for the production of multicoat protective and/or decorative coatings on substrate surfaces

摘要

The invention relates to a basecoat/clearcoat process in which the basecoat composition used contains as a film former a polyurethane resin which can be prepared by preparing an intermediate from (A) a mixture obtained from 10 to 90 mol % of linear polyether diols and 90 to 10 mol % of polyester diols, (B) diisocyanates, (C) compounds which contain two groups reactive toward isocyanate groups, at least some of these compounds having at least one group capable of forming anions, and the free isocyanate groups of the said intermediate are then reacted with (D) polyols containing at least three hydroxyl groups, and the reaction product obtained in this manner is transferred into an aqueous base, wherein a) the polyester diol is prepared from diols and an acid component which consists of 60 to 100% by weight of aliphatic dicarboxylic acids of more than 18 carbon atoms and of 40 to 0% by weight of aliphatic dicarboxylic acids of 2 to 18 carbon atoms, b) the equivalent ratio of the NCO groups to the total of the OH groups of (A) and the reactive groups of (C) is 2:1 to 1.05:1 and c) the equivalent of the OH groups of the component (D) to the NCO groups of the intermediate is 0.5:1 to 4:1.