LIGHT GYPSUM-CARDBOARD MANUFACTURING PROCESS Russian patent published in 2007 - IPC C04B38/10 C04B28/14 

FIELD: paper-and-pulp industry.

SUBSTANCE: manufacture of gypsum cardboard with specified-size pores distributed within gypsum core comprises following stages: blowing air into foaming substance to form foamed liquid, mixing the latter with mixture containing burnt gypsum and water to form fluid gypsum flour, pouring the flour into space between upper and lower sheets of lining paper for gypsum cardboard, shaping lining paper and fluid gypsum flour as cardboard, roughly cutting cardboard material followed by drying, and cutting dried cardboard material according to size of supposed product. Method is characterized by that, in order to reduce size of pores distributed in foamed fluid gypsum flour, a special agent is added to one of the following materials: to mother solution of foaming substance or to mixture thereof with water, content of above agent in foaming substance corresponding to 0.00001-0.005 wt parts per 100 wt parts burnt gypsum. Disclosed is also a method of manufacturing gypsum cardboard using a pore-increasing agent.

EFFECT: enabled rapidly and al low cost controlling pore size within gypsum core of product when manufacturing products with high-strength core and excellent adhesion for lining paper.

5 cl, 8 dwg, 1 tbl, 4 ex