Process for producing non-combustible gypsum board and non-combustible laminated gypsum board
AssigneesOnoda Cement Co., Ltd., Asahi Asbestos Co., Ltd.
InventorsTakao Take, Katsuaki Kaneko, Kokyo Kusunoki, Toshinobu Ichiba
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Abstract
A novel process for producing a non-combustible gypsum board and a non-combustible laminated gypsum board having superior practical physical properties, smoothly and efficiently is provided, which process is characterized by preparing a mixture consisting of a powdery gypsum consisting of 50 to 95 parts by weight of a hydrating gypsum and 5 to 50 parts by weight of gypsum dihydrate, a definite amount of fibers and a definite amount of a caking retarder and a necessary amount of water; molding the mixture before the hydrating gypsum is hydrated; and setting and drying the resulting molded material.
Claims20
A process for producing a non-combustible gypsum board which includes
- (1) preparing a mixture consisting essentially of
- (a) a powdery gypsum composed of 50 to 95 parts by weight of a hydraulic gypsum and 5 to 50 parts by weight of gypsum dihydrate,
- (b) 0.5 to 30 parts by weight of fibers based on 100 parts by weight of said powdery gypsum.,
- (c) 0.1 to 2.0 parts by weight of a setting retarder for the hydraulic gypsum based on 100 parts by weight of said hydraulic gypsum, and
- (d) water, and thereafter
- (2) molding said mixture before said hydraulic gypsum is completely hydrated, and
- (3) setting and drying the resulting molded material.
A process for producing a non-combustible laminated gypsum board which includes
- (1) preparing a mixture consisting essentially of
- (a) a powdery gypsum composed of 50 to 95 parts by weight of a hydraulic gypsum and 5 to 50 parts by weight of gypsum dihydrate
- (b) 0.5 to 30 parts by weight of fibers based on 100 parts by weight of said powdery gypsum
- (c) 0.1 to 2.0 parts by weight of a setting retarder for the hydraulic gypsum based on 100 parts by weight of said hydraulic gypsum, and
- (d) water sufficient to hydrate said hydraulic gypsum,
- (2) making said mixture into a sheet by a cylindrical gauze type sheet-making process,
- (3) laminating two or more of said green-sheets before said gypsum is said green sheet is completely hydrated,
- (4) molding the laminated sheets under a pressure of 30 to 500 Kg/cm.sup.2 to thereby integrate them, and
- (5) setting and drying the resulting molded laminate.
A composition for producing a non-combustible gypsum board that is composed of a mixture consisting essentially of
- (a) a powdery gypsum that includes 50 to 95 parts by weight of hydraulic gypsum and 5 to 50 parts by weight of gypsum dihydrate,
- (b) 0.5 to 30 parts by weight of fibers based on 100 parts by weight of said powdery gypsum, and
- (c) 0.1 to 2.0 parts by weight of a setting retarder for the hydraulic gypsum based on 100 parts by weight of said hydraulic gypsum.
Dependencies are inferred from the claim text.