PURPOSE: To maintain the surface of steel materials cleanly and to prevent oil stains by treating said materials with an aq. soln. contg. aliphatic dicarboxylic acids and the compds. expressed by the specific formula.
CONSTITUTION: Steel materials are treated with an aq. soln. or emulsion contg. ≥1 kinds of aliphat. dicarboxylic acids and ≥1 kinds of the compds. expressed by the formula (X, Y, Z are hydrogen atoms, hydroxyl groups, alkyl groups, carboxy groups, nitro groups or amino groups). There are, for example, oxalic acid, malonic acid, succinic acid, etc. as the aliphat. dicarboxylic acids, and it is preferable to contain said acids at about 0.01W10wt% in the soln. There are, for example, benzoic acid, toluic acid, ethyl benzoate, etc. as the compds. of the formula and are contained at about 0.01W10wt%. It is preferable to control said aq. soln. or emulsion to about 7W11pH with aq. ammonia, hydrazine, etc.
INUBUSHI AKIYOSHI
MATSUMOTO MASAO
MAEDA TOMOAKI
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