| 摘要 |
PROBLEM TO BE SOLVED: To obtain a transparent hydrophilic film maintaining its hydrophilic property over a long period of time, excellent in durability and useful for glass for construction to be protected from fouling by imparting specified surface roughness and ruggedness. SOLUTION: This hydrophilic film has 0.5-500nm, preferably 0.5-50nm average surface roughness Ra' obtd. by surface expansion of the center line average roughness in the range of 5μm×5μm at an arbitrary position of the surface, chiefly has ruggedness having <=0.5μm repetition length in the surface direction and consists preferably of oxides of P, Al and Si. This film is formed, e.g. by coating the surface of an article made of heat resistant stock such as glass with a surface treating agent consisting of phosphoric acid (salt), a soluble Al compd. such as aluminum nitrate, a water-soluble silicate such as lithium silicate, a nonionic surfactant and a solvent such as water and isopropanol and carrying out heat treatment at 300-700 deg.C.
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