MULTILAYER GYPSUM BOARD, RELATED METHODS AND SUSPENSIONS Russian patent published in 2024 - IPC C04B41/48 C04B28/14 B32B7/02 B32B13/08 E04C2/04 

FIELD: chemistry.

SUBSTANCE: invention relates to production of gypsum plasterboards. Composite gypsum plasterboard comprises sheet core and concentrated layer. Core of the sheet contains hardened gypsum, is formed from the first suspension containing water and plaster, has the first and the second sides of the core, which are defined in opposite directions. Concentrated layer interconnected with the first face side of the core has a density in the dry state which is at least 1.1 times higher than that of the sheet core in the dry state, is formed from a second suspension containing water, gypsum plaster, starch thickener, at least one water-soluble cellulose ether and optionally a copolymer containing polyacrylamide and acrylic acid. Starch thickener used is an ether derivative of starch with a degree of substitution - the ratio of substituted groups to glucose links - of at least 0.5, untreated by heat treatment, obtained by grafting foreign groups to the hydroxyl group of the glucose link of the starch molecule, wherein foreign groups are selected from: ethyl, hydroxyl ethyl, hydroxyl propyl, acetate, phosphate, sulphate. At least one water-soluble cellulose ether is selected from: methylcellulose, ethylcellulose, hydroxyethylcellulose, propylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose. Said starch thickener, water-soluble cellulose ether and copolymer are added to the second suspension to increase its viscosity by at least 100% for 30 s to prevent the second suspension from being washed out when the first suspension is distributed therein.

EFFECT: reduced weight of gypsum plasterboard while maintaining strength.

4 cl, 4 dwg, 2 tbl, 1 ex