| 摘要 |
PROBLEM TO BE SOLVED: To obtain a corrosion and discoloration suppressor which does not contain nitrous acid capable of forming nitrosoamine harmful for health at all and is practicably effective to aluminum and iron by incorporating a specific aliphat.α- orβ-dicarbonyl compd. and specific amines into this suppressor. SOLUTION: The corrosion and discoloration suppressor for Al and/or Fe is obtd. by incorporating >=1 kinds of the aliphat.α-dicarbonyl compd. expressed by formula I (Ra, Rb are H, 1 to 6C alkyl group, 2 to 5C alkenyl group or alkinyl group). The amines expressed by formula III (Ra, Rb, Rc are H, -OH, -NH2 , etc.) may be used by adding these amines to the aliphat.β-dicarbonyl compd. or the aliphat.β-dicarbonyl compd. expressed by formula II (Ra is H, 1 to 4C alkyl group, 2 to 4C alkenyl group, methoxy group, ethoxy group, Rb is H, 1 to 4C alkyl group, Rc is H, 1 to 3C alkyl group). The conventional suppressors, such as carboxylic acids, may be further added thereto.
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