Cationic resin and capped polyisocyanate curing agent suitable for use in electrodeposition

An electrodepositable composition comprising:

• (A) a cationic resin which is derived from a polyepoxide and which contains in the resin cationic salt groups and active hydrogen groups selected from aliphatic hydroxyl or primary or secondary amino;
• and present as a separate components
• (B) a fully capped polyisocyanate curing agent containing substantially no free isocyanate groups;
• said electrodepositable composition containing from about 0.02 to 1.0 milliequivalents phenolic hydroxyl groups calculated as ##STR3## per gram of resin solids, and from about 0.1 to 2.0 millieguivalents beta-hydroxy ester groups calculated as ##STR4## per gram of resin solids which is formed from ring opening a 1.2-epoxy group-containing material with a carboxylic acid;
• and wherein the phenolic hydroxyl groups and the beta-hydroxy ester groups are each separately present in one of the components selected from the group consisting of:
• (A). (B). optionally a separate component (C), and optionally a separate component (D), where (C) and (D) are different from (A) and (B) and from each other,
• wherein when the phenolic hydroxyl groups are present in component (A) they are produced by reaction of a polyhydric phenol with a polyepoxide with chain extension by a polyhydroxyl group-containing material where the polyhydric phenol is present in stoichiometric excess, and wherein when the phenolic hydroxyl groups are present in component (B) they are produced by capping the isocyanate groups of the polyisocyanate with materials selected from the group consisting of:
• i) materials having an aliphatic and phenolic hydroxyl group, and ii) a hydroxyl functional epoxide which is further reacted with a stoichiometric excess of a polyhydric phenol.