Patent ID: 8652580

Claim:
A method for manufacturing a mortar tile substantially having a surface structure where open pores are formed on a surface of the tile, the open pores being constituted of main pores and capillary holes communicated with the main pores, a first photocatalyst made of titanium oxide powder being contained in the tile and exposed on surfaces of the tile, surfaces of the main pores and surfaces of the capillary holes, and a second photocatalyst made of anatase titania powder and amorphous titania powder being situated on the surfaces of the tile, the surfaces of the main pores and the surfaces of the capillary holes and being exposed so that the main pores function as main tubes which allow absorption of moisture, foreign substances and decomposed materials therein and also function as a light introducing opening for exciting the first photocatalyst and the second photocatalyst situated on the surfaces of the tile, the surfaces of the main pores and the surfaces of the capillary holes, and the capillary holes also function as sub tubes which allow further absorption of moisture, foreign substances and decomposed materials therein and also function as a light introducing opening for exciting the first photocatalyst and the second photocatalyst situated on the surfaces of the tile, the surfaces of the main pores and the surfaces of the capillary holes, the mortar tile being manufactured by a method, comprising the steps of: preparing mixed powder having a water content of 2 to 7% by weight by mixing 30 to 80 parts by weight of calcium hydroxide powder, 20 to 70 parts by weight of porous aggregate, 0.1 to 5 parts by weight of the first photocatalyst, and water; filling the mixed powder into a mold of a molding machine; forming a formed body by pressurizing the filled mixed powder at a forming pressure of 15 to 80 MPa; curing the formed body by holding the formed body in a carbon dioxide atmosphere for 8 hours or more thus forming a cured formed body; and forming on a surface of the cured formed body a layer of a second photocatalyst having a film thickness of 50 to 200 nm by spraying a solution in which the second photocatalyst is dispersed on the surface of the cured formed body so as to manufacture the tiles.