| 摘要 |
PROBLEM TO BE SOLVED: To prevent so-called 'water-REPELLENT contamination' generated on an external wall of a building, by using a silicone sealing material at a joint. SOLUTION: The surface of a building material forming a building external wall is covered with a transparent layer containing an anatase-type titanium dioxide photocatalyst which is obtained by covering the building material surface with amorphous titania and then burning the same. The photocatalyst is optically excited by solar light, and the surface of the layer containing the photocatalyst is made ultra-hydrophillic to such an extent that a contact angel formed with water is 10 deg. or less. Even if molecules of an uncured silicone precursor liberated from the sealing material at a joint is diffused together with rainwater, it does not stuck to the building material surface on the periphery of the joint. Soot and dust attached to the surface is flushed away with rainwater, and therefore the surface is selfcleaned. |
