Coating compositions for aluminized steel sheets aluminized steel sheets treated with them and method of manufacturing thereof

摘要

PURPOSE: A coating composition for aluminized steel sheet which is harmless and obtains superior various properties such as corrosion resistance and coating film coherence, a surface treated aluminized steel sheet using the composition and a method for treating the surface of the aluminized steel sheet are provided. CONSTITUTION: The coating composition for aluminized steel sheet comprises 33.34 to 97.94 wt.% of the sum total of one or two aqueous organic resins selected from the group consisting of acryl resin and epoxy resin and pyrazolone, wherein the aqueous organic resins and pyrazolone are mixed in a ratio of 2:98 to 30:70; 0.98 to 16.66 wt.% of silane coupling agent; 0.98 to 33.34 wt.% of rare earth metal salts; and 0.1 to 16.66 wt.% of oxidant, wherein the acryl resin and epoxy resin have hydroxyl group or carboxyl group, wherein the rare earth metal salts are salts of one or more metals selected from the group consisting of Y and lanthanide elements, and wherein the rare earth metal salt is CeNO3. The aluminized steel sheet of which surface is treated with the coating composition is characterized in that the coating composition is adhered onto the surface of the aluminized steel sheet in an adhesion quantity of 50 to 800 mg/m¬2. The method comprises the steps of adhering a surface treating agent which contains 2.021 to 60 wt.% of the coating composition and a balance of water and organic solvent and has pH of 2.0 to 7.0, and in which the water and organic solvent are mixed in a ratio of 30:70 to 70:30 onto the aluminized steel sheet in a dried adhesion quantity of 50 to 800 mg/m¬2; and drying the surface treating agent adhered aluminized steel sheet at a temperature of 100 to 600 deg.C for 2 to 15 sec.