Surface-coating binders for cathodic electrocoating

Abstract

Surface-coating binders for cathodic electrocoating which comprise a protonized heat-curable reaction product (A), substantially free from epoxide groups, of (a) one or more Mannich bases, prepared from (a.sub.1) one or more polyhydric condensed phenols which may or may not contain ether groups. (a.sub.2) one or more secondary amines which contain one or more hydroxyalkyl groups, with or without one or more secondary amines which do not contain such groups, and (a.sub.3) formaldehyde or a formaldehyde donor, with (b) one or more epoxy resins, Which binder also contains from 1 to 40% by weight, based on the total of (A) + (B), of a water-insoluble non-ionic resin (B), free from epoxide groups and containing urethane groups, which resin has been obtained by reacting a partially blocked diisocyanate or higher polyisocyanate with a reaction product of a polyepoxide and one or more low molecular weight compounds containing SH and/or OH groups. These surface-coating binders are especially used for the cathodic electrocoating of metal articles.

Dependencies are inferred from the claim text.