COMPOSITE GYPSUM BOARD WITH HIGH CONTENT OF SALT IMPURITIES Russian patent published in 2025 - IPC B32B13/04 B32B5/14 B32B9/02 C04B28/14 B28B1/30 E04C2/26 

FIELD: construction; chemistry.

SUBSTANCE: invention relates to construction materials and relates to a composite gypsum board with high content of salt impurities. Board contains layers of hardened gypsum located between two cover sheets. Layers of hardened gypsum are formed at least from plaster and water. Layers of hardened gypsum include the core of the board and one or more layers of the coating layer. Hardened gypsum core makes a considerable thickness, at least approximately 90 % of the total thickness of all gypsum layers. First covering layer of the coating is applied on one side of the core facing the first (front) covering sheet. Second covering layer is applied on the other side of the core facing the second (back) covering sheet. At least the second coating layer is formed from a suspension containing starch. Plaster, as a rule, has a high content of salt impurities, for example, when plaster is calcined from certain sources of low-quality synthetic gypsum.

EFFECT: invention enables to improve adhesion, even when the core of the board and/or other gypsum layers are formed from plaster obtained from low-quality synthetic gypsum containing undesirable foreign salts, including chlorides, such as sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl₂) and/or calcium chloride (CaCl₂), which prevent binding of paper to the core.

13 cl, 5 dwg, 8 tbl