Abstract: The present invention is directed to provide a corrosion-resistant coating composition that is capable of forming a coating film with superior moisture resistance and a superior corrosion-resistant property for a long period, particularly over a long period even under acidic environmental conditions, further with superior storage stability. The corrosion-resistant coating composition of the present invention comprises a coating film-forming resin (A), a crosslinking agent (B), and a magnesium hydroxide (C), wherein the oil absorption of the magnesium hydroxide (C) is 70 g/100 g or less and wherein the BET specific surface area is 4.0 m2/g or less.

Abstract: A surface-treated steel material having cut edge corrosion resistance that is equal to or more than that of a chromate treatment without use of hexavalent chromium. The surface-treated steel material includes a coating film formed on a surface of a steel material through a plating layer that is obtained by immersing the steel material in a galvalume bath containing Mg. The coating film is formed using a coating composition containing a coating film-forming resin, a cross-linking agent, a predetermined vanadium compound, and trimagnesium phosphate; the vanadium compound is a compound satisfying a predetermined electrical conductivity; the content of the vanadium compound is restricted to a predetermined amount; the vanadium compound satisfies a predetermined pH; and the content of the trimagnesium phosphate is a predetermined amount.

Abstract: A surface-treated steel material includes a coating film formed on a surface of a steel material through a plating layer. The plating layer is obtained by immersing the steel material in a galvalume bath containing Mg. In the surface-treated steel material, the coating film is formed using a coating composition containing a coating film-forming resin, a cross-linking agent, a predetermined vanadium compound, and trimagnesium phosphate. The vanadium compound is a compound satisfying a predetermined electrical conductivity. The content of the vanadium compound is limited to a specified amount with respect to 100 mass % of the total of the coating film-forming resin solids and the cross-linking agent solids. The vanadium compound has a specified pH, and the content of the trimagnesium phosphate is a specified amount with respect to 100 mass % of the total of the coating film-forming resin solids and the cross-linking agent solids.

Abstract: The present invention relates to a paint film embodying a new parameter representing the resistance to raindrop fouling and having very satisfactory fouling resistance, particularly resistance to raindrop fouling, even ultra-low foulability, as well as high water resistance, acid resistance, alkali resistance, and crack resistance; a coating composition capable of providing said paint film; a method for forming a satisfactory paint film using said coating composition; and an article coated with said paint film. A coating composition comprising (I) a tetramethoxysilane partial hydrolyzed condensate and at least one member selected from (A) a film-forming resin and (B) an inorganic binder containing alkoxysilyl as a reactive curing group and having a water dynamic reverse tension (Tr) of not less than 55 dyn/cm; and an antifouling paint film containing the coating composition is provided.