摘要 |
<p>A fin for a heat exchanger which is highly hydrophilic and rustproof comprises a substrate of aluminum or an aluminum alloy having thereon a hydrophilic coat including therein a proteinaceous substance having a peptide bond, e.g., gelatin. Further enhancement of the fin's affinity for water is obtained by using a hydrophilic coat prepared by mixing a water soluble coating material, such as acrylic paint, with the proteinaceous substance. The coat is made by applying a water-based coating composition including the proteinaceous substance to a substrate and drying it in the temperature range of 100.degree. to 250.degree.C, and preferably 180.degree. to 220.degree.C.</p> |