Basf Corporation

Lynne G Bemer

Clint W Carpenter

Jeffrey S DePue

Zenon P Czornij

Glenn E Martin

Clint G Carpenter

The present invention is directed to a pigment dispersant composition for use with inorganic pigments in coating compositions. The dispersant composition includes a vinyl or acrylic copolymer and a transition metal or rare earth metal salt. The metal salt in combination with the copolymer is useful with inorganic pigment as it lowers the viscosity of the pigment dispersions, thus allowing a higher concentration of pigment in the dispersion and consequently providing dispersions with higher non-volatile content and higher pigment to binder ratios. The presence of the metal salts in the dispersant composition when used with surface coated metal flake pigment provides excellent corrosion reduction of the metal pigment, indicated by the reduction or elimination of hydrogen gassing by the pigment in a coating composition.

Waterborne basecoat with copolymer dispersant composition for inorganic

Copolymer dispersant composition for inorganic pigments

The invention is an aluminum flake pigment particle, surface treated transition metal or rare earth metal salt. The treated pigment particle has been found to be highly useful in water-borne coating compositions having a basic pH. The treated pigment particles experience significantly less hydrogen gassing in a high pH environment, and in water-borne coating compositions than untreated aluminum flake pigment particles. The treated pigment particles are also useful when combined with a pigment dispersant composition to further inhibit corrosion and gassing when the pigments are used in a coating composition.

Aluminum flake pigment treated with metal salts and coatings containing

The invention is a slightly water-soluble, time release corrosion inhibitor compound for treating aluminum flake pigment. The corrosion inhibitor is the reaction product of a water-soluble metal salt including metals selected from the group consisting of yttrium and rare earth metals and an anionic metal salt including transition metal oxo-complexes and soluble salts of silicon and mixtures thereof. The corrosion inhibitor is useful for preventing hydrogen gassing of aluminum pigment particles. The compound is particularly useful for preventing gassing of bare and chromated aluminum pigment particles in aqueous compositions and in water-borne coating compositions having a basic pH. The pigment particles used in combination with the corrosion inhibitors of the present invention experience significantly less hydrogen gassing in a high pH aqueous environment and in water-borne coating compositions having high pH, than aluminum flake pigment particles and coatings without the corrosion inhibitor. The corrosion inhibitor is also effective when combined with a second corrosion inhibitor, such as a water-soluble salt of yttrium or rare earth metal in a coating composition.

Aluminum flake pigment treated with time release corrosion inhibiting

A compound is described that is useful for metal surface modification, particularly aluminum flake pigment surface modification, having the formula: ##STR1## where X, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, D.sub.1, D.sub.2, D.sub.3, j, k, m, and n are as defined herein. A method for surface modification of a metallic flake pigment with the compound and compositions containing the surface modified metallic flake pigment is also described.

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Northville, MI, United States of America

Lynne G Bemer