Nippon Paint Compnay, Ltd.

Youji Hirasawa

Hisataka Yamamoto

A method for the treatment of a metal surface, which comprises applying a treating liquid comprising an emulsion and a water-soluble chromium compound containing 30 to 90% by weight of hexavalent chromium and optionally a water-insoluble white carbon to a metal surface and drying the resultant, said treating liquid containing substantially no alkali metal ion, said emulsion being prepared by emulsion-polymerizing .alpha., .beta.-monoethylenically unsaturated monomer in the presence of an emulsifier selected from the group consisting of a polyacrylic acid and a copolymer of acrylic acid and a monomer selected from the group consisting of methacrylic acid, an acrylamide, a methacrylamide and a hydrophilic monomer of the formula: ##STR1## wherein A is hydrogen atom or methyl; R is a substituted or unsubstituted alkylene having 2 to 4 carbon atoms; and X is a functional group containing at least one of oxygen atom, phosphorus atom and sulfur atom, said emulsifier being used in an amount of 20 parts by weight or more (in the solid content) to 100 parts by weight of the .alpha.,.beta.-monoethylenically unsaturated monomer.

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Hirakata, Japan

Youji Hirasawa