HARD GYPSUM BOARD AND ITS POURING MOLDING METHOD

PURPOSE:To provide a gypsum board which can be effectively fastened by a nail or a machine screw and has hardness, flexural rigidity and impact resistance by covering a gypsum core formed by dispersing fiber of prescribed pts.wt. per prescribed pts.wt. of burnt gypsum in the gypsum core with base paper, and setting the specific gravity in a specific range. CONSTITUTION:Slurry is prepared and is poured between two sheets of base paper 3. Next, a hard gypsum board 1 having a prescribed dimension is molded and dried through a forming roller. In that case, fiber of 0.5 to 5 pts.wt. per 100 pts.wt. of burnt gypsum is dispersed in a gypsum core, and is covered with the base paper 3. The specific gravity is set in 1 to 1.6. Next, a rate of inorganic and organic fiber is set in 1:0.05 to 1:1. The gypsum core also contains a water reducing agent by a quantity not more than 2 pts.wt. per 100 pts.wt. of the burnt gypsum. Further, the gypsum core also contains a foam agent not more than 0.05 pts.wt. per 100 pts.wt. of the burnt gypsum. The fiber of 0.5 to 5 pts.wt. per 100 pts.wt. of the burnt gypsum and mixed water of 30 to 65wt.% are mixed together. Therefore, a board which can be fastened by a nail or a machine screw and is excellent in hardness, fireproof performance and impact resistance can be formed.