US 6,758,916 B1 · Composition and process for treating metals

Abstract

A chromium free conversion coating at least equivalent in corrosion protective quality to conventional chromate conversion coatings can be formed on metals, particularly cold rolled steel, by a dry-in-place aqueous acidic liquid that preferably has a pH value between 0.5 and 5.0 and comprises: (A) “fluorometallate” anions consisting of (i) at least four fluorine atoms, (ii) at least one atom of an element selected from the group consisting of titanium, zirconium, hafnium, silicon, aluminum, and boron, and, optionally, one or more of (iii) ionizable hydrogen atoms and (iv) oxygen atoms; (B) a component of divalent or tetravalent cations of elements selected from the group consisting of cobalt, magnesium, manganese, zinc, nickel, tin, copper, zirconium, iron, and strontium in such an amount that the ratio of the total number of cations of this component to the number of anions in component (A) is at least about 1:5 but not greater than about 3:1; (C) a component selected from the group consisting of phosphorus-containing inorganic oxyanions and phosphonate anions; and (D) a component of polymers of hydroxy styrene, modified by substitution on the aromatic rings of the polymers of substituted aminomethyl moieties, in which the substituents (other than the carbon atom that is directly bonded to an aromatic ring in the polymer) on the amino nitrogen atom jointly contain at least two carbon atoms and at least one hydroxy moiety but neither of these substituents on the amino nitrogen atom individually contains more than half as many hydroxyl moieties as it has carbon atoms, unless it contains only one carbon atom.

Claims38

Dependent claims

An acidic aqueous liquid composition that is suitable for use directly, after being diluted with water, or both directly and after being diluted with water, for generating a corrosion reducing coating over a metal surface when contacted therewith, said composition comprising water and:

(A) a component of “fluorometallate” anions, each of said anions consisting of (i) at least four fluorine atoms, (ii) at least one atom of an element selected from the group consisting of titanium, zirconium, hafnium, silicon, aluminum, and boron, and optionally, one or both of (iii) ionizable hydrogen atoms, and (iv) one or more oxygen atoms;
(B) a component of divalent or tetravalent cations of elements selected from the group consisting of cobalt, magnesium, manganese, zinc, nickel, fin, copper, zirconium, iron, and strontium;
(C) a component selected from the group consisting of phosphorus-containing inorganic oxyanions and phosphonate anions;
and
(D) a component of water-soluble, water-dispersible, or both water-soluble and water-dispersible polymers of hydroxy styrene, modified by substitution on the aromatic rings of the polymers of at least mono-substituted aminomethyl moieties, in which the substituents (other than the carbon atom that is directly bonded to an aromatic ring in the polymer) on the amino nitrogen atom jointly contain at least two carbon atoms and at least one hydroxy moiety but neither of these substituents individually contains more than half as many hydroxyl moieties as it has carbon atoms, unless it contains only one carbon atom.

2 more elements

(A) a source of a component of “fluorometallate” anions, ach of said anions consisting of (i) at least four fluorine atoms, (ii) at least one atom of an element select d from the group consisting of titanium, zirconium, hafnium, scion, aluminum, and boron, and, optionally, one or both of (iii) ionizable hydrogen atoms, and (iv) one or more oxygen atoms;
(B) a source of a component of divalent or tetravalent cations of elements selected from the group consisting of cobalt, magnesium, manganese, zinc, nickel, tin, copper, zirconium, iron, and strontium;
(C) a source of a component selected from the group consisting of phosphorus-containing inorganic oxyanions and phosphonate anions;
and
(D) a source of a component of water-soluble, water-dispersible, or both water-soluble and water-dispersible polymers of hydroxy styrene, modified by substitution on the aromatic rings of the polymers of at least mono-substituted aminomethyl moieties, in which the substituents (other than the carbon atom that is directly bonded to an aromatic ring in the polymer) on the amino nitrogen atom jointly contain at least two carbon atoms and at least one hydroxy moiety but neither of these substituents individually contains more than half as many hydroxyl moieties as it has carbon atoms, unless it contains only one carbon atom.

2 more elements

An acidic aqueous liquid composition according to calm 24, wherein component (D) has the chemical characteristics of a polymer that is a product of reaction of:

(A′) at least one precursor phenolic polymer or copolymer which does not bear any substituted aminomethyl substituents on its aromatic rings;
(B′) at least one aldehyde, ketone, or mixture thereof;
and
(C′) at least one amine.

1 more element

Dependencies are inferred from the claim text.

Composition and process for treating metals

Life of this patent

Composition and process for treating metals

Life of this patent

Abstract

Claims38