Nippon Paint Compnay, Ltd.

Sumitomo Metal Industries, Inc.

Hisataka Yamamoto

Masaaki Takimoto

Satoshi Ikeda

Nobukazu Suzuki

Toshiaki Shiota

Yasushi Hosoda

Kohichi Kimura

Minao Izumi

Taketosi Odawa

Youji Hirasawa

An anticorrosive primer composition comprises (1) 100 parts by weight of an epoxy resin having a number-average molecular weight of from 500 to 10,000, (2) from 10 to 60 parts by weight of an aromatic polyamine containing from 2% to 30% by weight, based on the aromatic polyamine, of a promoter selected from the group consisting of phenol compounds and cresol compounds, (3) from 10 to 60 parts by weight of a polyisocyanate, (4) from 10 to 40 phr, based on the sum of components (1), (2), and (3), of silica particles of colloidal silica or fumed silica or a mixture of these, (5) from 0.5 to 5 phr of a lubricant, and (6) an organic solvent. The composition is particularly suitable for use to apply onto the chromate coating of a chromated, zinc-plated steel sheet.

Anticorrosive primer composition

A thermosetting coating composition suitable for use in the production of coated and precoated metals comprises (A) a thermosetting resin-hardener mixture which is a mixture of at least one base resin and at least one hardener, (B) an aluminum silicate colloid which is a mixture of Al.sub.2 O.sub.3 or Al(OH).sub.3 with SiO.sub.2, (C) a melamine cyanurate compound, and (D) a solvent in such an amount that the composition has a viscosity adequate for coating. Optionally a pigment and/or lubricant may be added.

Thermosetting coating composition

A colloidal particle dispersion is disclosed, comprising mainly (1) a fumed silica or fumed aluminum silicate, (2) a colloidizing agent (aid) which is at least one compound selected from the group consisting of a phosphoric acid compound, a molybdic acid compound, a boric acid compound, and a silicic acid compound, and (3) water, and a method for preparing the same is disclosed. Further, a water-based coating composition is disclosed, which comprises a water-based coating composition and incorporated therein a colloidal particle dispersion comprising mainly (1) fumed silica or fumed aluminum silicate, (2) a colloidizing agent (aid) which is at least one compound selected from the group consisting of a phosphoric acid compound, a molybdic acid compound, a boric acid compound, and a silicic acid compound, and (3) water, and a method for preparing the same is disclosed. Furthermore, the coating method with which the above water-based coating composition on a metal substrate is disclosed.

Colloidal particle dispersion and water-based coating composition

An anticorrosive coating composition, comprising 0.05 to 20% by weight of melamine cyanurate, 5 to 30% by weight of a thermosetting resin, 0 to 20% by weight of a curing agent, and 40 to 95% by weight of a solvent (providing that the total amount of said components is 100% by weight). It obviates the necessity for incorporating silica, a hydrophilic resin, and an electroconductive pigment and allows control of the density of electrification points in a film of a coating material using the composition.

Anticorrosive coating composition

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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Tokyo, Japan

Hisataka Yamamoto