Modifier for hydrophilicity, hydrophilic modification method and aluminum material or aluminum alloy material modified hydrophilic thereby

摘要

A modifier for hydrophilicity and a hydrophilic modification method which are capable of suppressing not only the odor of the resulting hydrophilic coat itself but also the unpleasant odor emanation after exposure to odorants and retaining the hydrophilicity even during a long period of use, and an aluminum material or aluminum alloy material by said hydrophilic modification method, which is used suitably for heat exchangers and the like are provided. A modifier for hydrophilicity which comprises a modified polyvinyl alcohol containing a group represented by the formula (I) on a side chain thereof; CHEM in the formula, n represents an integer of 1 to 500, R1 represents a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, and R2 represents a hydrogen atom or a methyl group, said group represented by the above formula (I) accounting for 0.01 to 20 mole percent of the sum of hydroxyl groups and acetoxy groups in said modified polyvinyl alcohol, and said modified polyvinyl alcohol accounting for 0.1 to 30% by mass relative to said modifier for hydrophilicity.