Treatment of metal parts to provide rust-inhibiting coatings
AssigneeMan-Gill Chemical Company
InventorsRandall J. Brent, David A. Blaha
Life of this patent
Estimating the term…
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.
Claims28
A method of producing an adherent and corrosion-inhibiting multi-layer coating on small metal parts comprising the steps of
- (A) phosphating the metal parts with an aqueous metal phosphating solution;
- (B) electrophoretically depositing a first film of a siccative organic coating composition on the phosphated metal parts contained on a rack or in a rotatable porous barrel wherein said organic coating composition is selected from anodic and cathodic coating compositions;
- (C) non-electrophoretically applying a second film of a cathodic or anodic composition over the first film prior to curing of the film deposited in (B) to form a seal coat, said second film comprising at least one film-forming organic resin component provided:
- that the compositions of second film is a cathodic composition when the composition of the first film is anodic;
- and the composition of the second film is anodic when the composition of the first film is cathodic;
- and
- (D) curing the coatings on the metal parts;
- wherein the small metal parts comprise nuts, bolts, fasteners, screws, small sub-assemblies, and mixtures thereof.
A method of producing an adherent and rust-inhibiting multi-layer finish on small metal parts wherein the metal is 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 cathodic or anodic thermosetting resin and passing through said parts, an electric current to electrodeposit resin particles on the phosphate-coated parts by electrophoresis to form a first resin film;
- (D) contacting the parts having the first resin film with an aqueous composition prior to curing of the first resin film to form a second film of the aqueous composition over the first film as a seal coat, said aqueous composition comprising water and at least one water-dispersible or emulsifying anodic or cathodic film-forming resin provided:
- that the compositions of second film is a cathodic composition when the composition of the first film is anodic;
- and the composition of the second film is anodic when the composition of the first film is cathodic;
- and
- (E) curing the films on the metal parts by subjecting the parts to an elevated temperature for a time sufficient to cure the films;
- wherein the small metal parts comprise nuts, bolts, fasteners, screws, small sub-assemblies, and mixtures thereof.
The method of claim 24 wherein the film-forming resin (1) comprises a mixture of an epoxy resin and an aminoplast resin.
A method of producing an adherent and corrosion-inhibiting multi-layer coating on small metal parts comprising the steps of
- (A) phosphating the metal parts with an aqueous metal phosphating solution;
- (B) electrophoretically depositing a first film of a siccative organic coating composition on the phosphated metal parts contained on a rack or in a rotatable porous barrel wherein said organic coating composition is selected from anodic and cathodic coating compositions, wherein the organic coating composition comprises at least one film-forming organic resin component and a fluoroalkene polymer;
- (C) non-electrophoretically applying a second film of a cathodic or anodic composition over the first film prior to curing of the film deposited in (B) to form a seal coat, said second film comprising at least one film-forming organic resin component provided:
- that the compositions of second film is a cathodic composition when the composition of the first film is anodic;
- and the composition of the second film is anodic when the composition of the first film is cathodic;
- and
- (D) curing the coatings on the metal parts.
A method of producing an adherent and corrosion-inhibiting multi-layer coating on small metal parts comprising the steps of
- (A) phosphating the metal parts with an aqueous metal phosphating solution;
- (B) electrophoretically depositing a first film of a siccative organic coating composition on the phosphated metal parts contained on a rack or in a rotatable porous barrel wherein said organic coating composition is selected from anodic and cathodic coating compositions;
- (C) non-electrophoretically applying a second film of a cathodic or anodic composition over the first film prior to curing of the film deposited in (B) to form a seal coat, said second film comprising at least one film-forming organic resin component and a fluoroalkene polymer provided that the compositions of second film is a cathodic composition when the composition of the first film is anodic;
- and the composition of the second film is anodic when the composition of the first film is cathodic;
- and
- (D) curing the coatings on the metal parts.
A method of producing an adherent and corrosion-inhibiting multi-layer coating on small metal parts comprising the steps of
- (A) phosphating the metal parts with an aqueous metal phosphating solution;
- (B) electrophoretically depositing a first film of a siccative organic coating composition on the phosphated metal parts contained on a rack or in a rotatable porous barrel wherein said organic coating composition is selected from anodic and cathodic coating compositions, wherein the organic coating composition comprises at least one film-forming organic resin component and at least one additive selected from mica, talc, carbon black, iron oxide and calcium carbonate;
- (C) non-electrophoretically applying a second film of a cathodic or anodic composition over the first film prior to curing of the film deposited in (B) to form a seal coat, said second film comprising at least one film-forming organic resin component provided:
- that the compositions of second film is a cathodic composition when the composition of the first film is anodic;
- and the composition of the second film is anodic when the composition of the first film is cathodic;
- and
- (D) curing the coatings on the metal parts.
A method of producing an adherent and corrosion-inhibiting multi-layer coating on small metal parts comprising the steps of
- (A) phosphating the metal parts with an aqueous metal phosphating solution;
- (B) electrophoretically depositing a first film of a siccative organic coating composition on the phosphated metal parts contained on a rack or in a rotatable porous barrel wherein said organic coating composition is selected from anodic and cathodic coating compositions;
- (C) non-electrophoretically applying a second film of a cathodic or anodic composition over the first film prior to curing of the film deposited in (B) to form a seal coat, said second film comprising at least one film-forming organic resin component and at least one additive selected from mica, talc, carbon black, iron oxide and calcium carbonate provided that the compositions of second film is a cathodic composition when the composition of the first film is anodic;
- and the composition of the second film is anodic when the composition of the first film is cathodic;
- and
- (D) curing the coatings on the metal parts.
Dependencies are inferred from the claim text.