| 摘要 |
PROBLEM TO BE SOLVED: To establish a method for continuously producing a galvanized steel sheet having a modified surface layer stably for a long period of time, while prolonging the liquid life even when using a circulated and recovered treatment liquid of which the composition changes. SOLUTION: The method for continuously producing the galvanized steel sheet having the modified surface layer comprises the steps of: continuously passing a galvanized steel sheet; spraying a surface treatment agent indispensably containing a proton ejective P component onto the surface of the passing steel sheet; and then removing an aqueous solvent contained in the treatment agent to form the modified surface layer containing P on the surface of a plated layer, wherein the surface treatment agent includes a treatment liquid recovered in a spraying step, and includes the proton ejective P component, further an organic resin containing a carboxy group, and Zn ions so as to satisfy a particular condition. COPYRIGHT: (C)2006,JPO&NCIPI
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