| abstract |
A treatment method for hydrophilicity for a heat exchangernwhich can maintain the deodorizing property and hydrohilicityneven after a long-time use, and a heat exchanger thus treatednfor hydrophilicity by said method are provided. After anprevious acidic washing treatment, a heat exchanger is subjectednto a chemical transformation treatment to form a chemicalnconversion coating film using a chromium chromate treatment agent,nchromium phosphate treatment agent, or treatment agent ofnzirconium series, followed by a treatment for hydrophilicitynusing a treatment agent for hydrophilicity, which contains silicanparticulates and polymer of vinyl alcohol series in aqueous mediumnin a weight ratio 30:70∼70:30 and in tot al content of 1∼25nweight percent, and in which said silica particulates are coatednwith said polymer of vinyl alcohol series, and dispersed as coatednparticles of the average particle diameter of 5∼1000 nm in aqueousnmedium, to form the coating film so as to amount to 1∼3 g/m 2 . |