摘要 |
A water-based metal surface treatment composition for forming a lubricating film with excellent marring resistance, characterized in that it comprises (a) a water-compatible urethane resin which contains bisphenol skeletons and carboxyl groups in the resin backbone and has an average molecular weight of 3,000 or higher and which has been synthesized through reaction of an isocyanate in which the content of nitrogen atoms participating in the isocyanate reaction is 2 to 13 wt. % and the ratio of nitrogen atoms participating in urea bond formation to the nitrogen atoms participating in the isocyanate reaction is 10/100 to 90/100, (b) a hardener, (c) silica, and (d) a polyolefin wax, and that the sum of the ingredients (a) and (b) is 50 to 95 wt. % based on the whole composition (e) on a solid basis, the amount of functional groups contained in the ingredient (b) is 0.10 to 1.00 equivalent to the carboxyl groups contained in the backbone of the ingredient (a), the amount of the ingredient (c) is 3 to 40 wt. % based on the composition (e) on a solid basis, and the amount of the ingredient (d) is 2 to 30 wt. % based on the composition (e) on a solid basis.
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