Method for curing a coating film

Claim 1

A method for curing a coating film upon a coated electroconductive object comprising in combination the steps of: a. immersing said object in an electrophoretic bath comprising an aqueous dispersed composition characterized in that said composition is both electrodepositable as an adherent film upon an anode immersed therein and polymerizable thereon by applying ionizing radiation, said aqueous dispersed composition comprising an aqueous dispersion of an acidic film-forming binder, and said acidic film-forming binder being a conjugated unsaturated fatty acid, conjugated unsaturated oil or mixture thereof modified alkyd resin having an oil length in the range of 10-60 weight percent and a resin acid value in the range of 30-100, the carboxylic groups of said modified alkyd resin being neutralized with at least one water-soluble base selected from amino compounds, inorganic alkali compounds and alkaline salts, in the range of 0.7 to 1.2 stoichiometrical equivalents of the carboxyl groups of said modified alkyd resin, b. providing a direct current through said bath sufficient to effect deposition of a film of said composition upon said object as an anode by providing a difference of electrical potential between said anode and other electrode, c. transferring the resultant coated object from said bath containing said composition into an irradiation zone, and d. applying to the electrodeposited film upon said object, a 0.1-40 M rad dose of ionizing radiation until said film is cured by polymerization.

Claim 2

A method for curing a coating film upon a coated electroconductive object comprising in combination the steps of: a. immersing said object in an electrophoretic bath comprising an aqueous dispersed composition characterized in that said composition is both electrodepositable as an adherent film upon an anode immersed therein and polymerizable thereon by applying ionizing radiation, said aqueous dispersed composition comprising an aqueous dispersion of an acidic film-forming binder, and said acidic film-forming binder being a conjugated unsaturated fatty acid, conjugated unsaturated oil or mixture thereof modified alkyd resin having an oil length in the range of 10-60 weight percent and a resin acid value in the range of 30-100, the carboxylic groups of said modified alkyd resin being neutralized with at least one water-soluble base selected from amino compounds, inorganic alkali compounds and alkaline salts, in the range of 0.7 to 1.2 stoichiometrical equivalents of the carboxyl groups of said modified alkyd resin, b. providing a direct current through said bath sufficient to effect deposition of a film of said composition upon said object as an anode by providing a difference of electrical potential between said anode and other electrode, c. transferring the resultant coated object from said bath containing said composition into an irradiation zone, and d. applying to the electrodeposited film upon said object, a 0.1-40 M rad dose of ionizing radiation until said film is cured by polymerization.