Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.