Treatment of metal parts to provide rust-inhibiting coatings
AssigneeMan-Gill Chemical Company
InventorsRandall J. Brent, David A. Blaha
Life of this patent
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Abstract
The invention describes a method of producing an adherent and corrosion-inhibiting multi-layer coating on metal parts comprising the steps of (A) phosphating the metal parts with an aqueous metal phosphating solution; (B) electrophoretically depositing a film of a siccative organic coating composition on the phosphated metal parts; (C) applying a second film of a composition comprising at least one film-forming organic resin component as a seal coat; (D) curing the coating on the metal parts; and optionally (E) applying a corrosion-inhibiting film as a top seal coat.
Claims27
A method of producing an adherent and corrosion-inhibiting multi-layer coating on metal parts comprising the steps of
- (A) phosphating the metal parts with an aqueous metal phosphating solution;
- (B) electrophoretically depositing a film of a siccative organic coating composition on the phosphated metal parts contained on a rack or in a rotatable porous barrel to form a first film;
- (C) non-electrophoretically applying a second film of a composition prior to curing of the coating deposited in (B) to the electrophoretically coated metal parts to form a seal coat, said second film comprising at least one film-forming organic resin component;
- (D) curing the coatings on the metal parts;
- and
- (E) applying a corrosion-inhibiting film as a top seal coat on the cured coated metal parts.
A method of producing an adherent and rust-inhibiting multilayer finish on metal parts selected from the group consisting of ferrous metal, zinc, aluminum, and alloys thereof comprising the steps of
- (A) immersing the parts in an aqueous acidic zinc, lead, iron or manganese phosphating solution for a period of time and at a temperature sufficient to deposit an adherent phosphate coating on said metal parts;
- (B) rinsing the phosphate-coated parts with an aqueous acidic solution containing an under-paint corrosion inhibitor;
- (C) immersing the phosphate-coated metal parts contained on a rack or in a rotatable porous barrel in an aqueous dispersion, emulsion or solution of a thermosetting resin and passing through said parts, an electric current thereby electrodepositing resin particles on the phosphate-coated parts by electrophoresis to form a first resin film;
- (D) contacting the electrophoretically coated parts with an aqueous composition prior to curing of the coating deposited in (B) to form a second film of the aqueous composition over the first film as a seal coat, said second film comprising water and at least one water-dispersible or emulsifying film-forming resin;
- (E) curing the films on the metal parts by subjecting the parts to an elevated temperature for a time sufficient to cure the films;
- and
- (F) contacting the cured resin-coated parts with oil, oil containing a corrosion inhibitor, or a corrosion inhibitor without oil to form a top seal coat.
Dependencies are inferred from the claim text.