GYPSUM BOARD COMPRISING A HIGH LEVEL OF SALT CHLORIDE AND A PERFORATED SHEET AND METHOD ASSOCIATED WITH THEM Russian patent published in 2023 - IPC C04B28/14 B32B13/08 

FIELD: construction materials.

SUBSTANCE: invention relates to a gypsum board formed from synthetic gypsum and other sources of gypsum having high concentrations of chloride salt, as well as to a method for making a gypsum board with at least a perforated back cover sheet, as well as a wall system where the gypsum board is used. A flat gypsum board comprises a board core layer comprising set gypsum; a front paper cover sheet, wherein the front paper cover sheet is free from a plurality of perforations; and a back paper cover sheet having a plurality of perforations extending therethrough; moreover, the stucco contains calcium sulphate hemihydrate, and the aqueous suspension comprises: at least 60% wt. of said calcium sulphate hemihydrate on a dry basis, from about 500 parts by weight to about 3000 parts by weight of chloride anions per 1,000,000 parts by weight of said calcium sulphate hemihydrate, and water at a weight ratio of water to calcium sulphate hemihydrate from 0.2:1 to 1.2:1, wherein the back cover sheet has a perforation coverage in the range of about 0.78 perforations/cm² (about 5 perforations/inch²) to about 7.75 perforations/cm² (about 50 perforations /inch²).

EFFECT: improved adhesion between the board core layer comprising a large amount of foreign salts and one or more cover sheets, in particular the back cover sheet.

10 cl, 9 dwg, 1 tbl