Polymeric additive for cathodic electrocoating compositions for improved throw power

Abstract

An improved aqueous cathodic electrocoating composition having a binder of an epoxy-amine adduct which is of an epoxy resin that has been reacted with an amine, and a blocked polyisocyanate crosslinking agent; wherein the improvement is the use of a water soluble electrically conductive polymeric additive of a polyepoxy hydroxy ether resin reacted with a ketimine and optionally up to 60% of the epoxy end groups of the resin reacted with another amine and the resin has an epoxy equivalent weight of about 500-900, a weight average molecular weight of about 1,000-5,000 and an electrical conductivity of about 4,000-8,000 microsiemens to provide an electrocoating composition having improved throw power.

Dependencies are inferred from the claim text.