ALUMINUM-MADE FIN MATERIAL FOR HEAT EXCHANGER AND SURFACE TREATING AGENT THEREFOR

摘要

PROBLEM TO BE SOLVED: To impart an excellent hydrophilicity to the surface of an aluminum- made fin material for heat exchangers to thereby prevent water drops from being formed and to prevent a metal mold from being worn in the step of press forming by forming, on the surface, a film from a surface-treating agent comprising a polyvinyl alcohol having a specified compsn. and a polyethylene glycol. SOLUTION: The surface treating agent comprises a polyvinyl alcohol contg. vinyl alcohol units, epoxidized vinyl units, and aliph. vinyl ester units and a polyethylene glycol. The polyvinyl alcohol has a degree of polymn. of 300-3,300, a degree of saponification of 90% or higher, and a content of epoxidized vinyl units of 0.2-12 mol.%. A polyethylene glycol having a mol.wt. of 600-20,000 is compound in an amt. of 0.05-5 pts.wt. based on 100 pts.wt. polyvinyl alcohol. An aq. soln. of the surface treating agent is applied to the surface of an aluminum-made fin material and dried to form a coating film on the surface.