| 摘要 |
PURPOSE: An agent for preventing the surface discoloration of a cold rolled steel sheet generated in an alkali wash tank or electrolytic cell using hexamethylenetetramine and imidazole is provided, which prevents corrosion of a steel sheet by forming a temporary rust-preventing layer on the steel surface. CONSTITUTION: This agent comprises 87.4 to 75.7% by weight of pure water, 3.0 to 5.0% by weight of imidazole, 2.0 to 4.0% by weight of hexamethylenetetramine, 0.2 to 1.2% by weight of trifluoroantimony, 4.0 to 6.0% by weight of tetrasodium salt of ethylenediaminetetraacetic acid, 2.0 to 5.0% by weight of benzoic acid, 0.2 to 0.8% by weight of 3,5-diaminobenzoic acid and 1.2 to 2.5% by weight of polyoxyethylene laurylamine of formula 1. In formula, m is 1 to 7.
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