| 摘要 |
PURPOSE:To obtain a corrosionproof steel sheet superior in processability and electrodeposition coating properties, by a method wherein a film layer mainly comprised of urethane resin and composite substance or mixed substance of silicon dioxide is provided on an alloyed zinc plated steel sheet containing a specific quantity of Fe to which zinc plating and heat treatment have been performed and comprising of residue zinc. CONSTITUTION:A coating solution comprised of 100pts.wt. water-soluble urethane emulsion, 50pts.wt. colloidal silica, 9pts.wt. gamma-mercaptopropyl trimethoxyl silane and 750pts.wt. distilled water is applied to an alloyed zinc plated steel sheet, whose Fe content is 6-20wt.%, with a bar coater and baked at 180 deg.C for 1min. With this construction, as a film layer whose SiO2/urethane resin is equal to 0.40 and mean coating build-up is 1.5g/m<2> is formed, a corrosionproof steel sheet whose peeling properties of a film and electrodeposition coating are favor able is obtained. |
