| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal heat exchanger made of a metal containing aluminum without containing hexavalet chromium, having a high hydrophilicity, corrosion resistance, deodorizing property over a long term. SOLUTION: A first protective layer formed of a chemical conversion coating without containing hexavalent chromium on the surface of an aluminum-containing metal base-material of a heat exchanger, and a second protective layer is formed on the first protective layer. The second layer is formed of a hydrophilic and hardly water-soluble resin film containing a reaction product of a resin component (a) containing a water-soluble polymer having at least one of hydrophilic group selected from the groups consisting of primary, secondary, or tertiary amino, quaternary ammonium, amide, carboxyl, sulfone, ethylene oxide, phosphonate, and hydroxyl, and a cross- linkable group selected from the groups of amide, carboxy, and hydroxyl, and a different kind from the above selected hydrophilic group, and a cross-linking agent component (b) containing (i) a trivalent chromium component and (ii) a fluorocomplex salt compound in the total amount exceeding an equivalent for cross-linking the resin components.
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