Electrophoretic coating of epoxy resins from non-aqueous systems

Abstract

An emulsion is prepared which comprises about 8 to about 20 percent of a solvent, about 0.5 to 5 percent of an epoxy resin dissolved in the solvent to form a discontinuous phase, about 75 to about 90 percent of a precipitant as the continuous phase, and an emulsifier in an amount sufficient to react stoichiometrically with the epoxy and hydroxyl groups on the epoxy resin up to about 900% in excess of stoichiometric. A conductive workpiece is placed in the emulsion about 1/2 to about 2 inches from an electrode which is also immersed in the emulsion. A direct electric current potential is applied between the workpiece and the electrode with the workpiece as the anode. About 50 to about 400 volts and about 2 to about 50 milliamperes are used until a coating of the desired thickness has been deposited on the workpiece. The solvent and precipitant are preferably ketones such as cyclohexanone, and methylethylketone or isobutylketone, respectively. The epoxy resin is preferably a bisphenol A epoxy resin having an average molecular weight of about 2000 to about 15,000. The emulsifier is preferably an amine.

Dependencies are inferred from the claim text.