| 摘要 |
PURPOSE:To inhibit the turning-round of a fluid for the pretreatment of a surface to be coated for the improvement of corrosion resitance, by forming the electric conductive coating film of specified resin which exhibits remarkable water-resisting power on the surface of a steel sheet to be handled as a back side. CONSTITUTION:After a steel sheet is washed with hot water 1, an aqueous solution is applied 2 onto a surface (b) to be uncoated by a roll coating method or the like, while holding said surface (b) to be uncoated downside. When an aqueous solution containing 5-50% singly polyethylene imine, silica sol-polyethylene imine or water-soluble acryl resin is used as said aqueous solution, an electric conductive coating film of 0.1-2.5mum in dried thickness is obtained. After the coating film is formed in this way, it is dried 3 at 40-300 deg.C to provide it with water-resisting power. Thereafter, phosphating treatment 4 and chromic acid sealing 5 are performed as pretreatment for coating. Paint is applied 6 onto only the surface (a) to be coated on which the precoating film has been formed by the pretreatment, to obtain a single side-coated steel sheet.
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