COMPOSITION PROVIDING STRENGTH IN DRY STATE, ITS USE AND METHOD FOR PRODUCING PAPER, CARDBOARD AND SIMILAR MATERIALS Russian patent published in 2021 - IPC D21H17/29 D21H17/37 D21H21/18 

FIELD: paper; cardboard production.

SUBSTANCE: invention relates to an aqueous composition that provides dry strength, suitable for use in the manufacture of paper and cardboard. The composition includes a mixture of an artificial polymer component and a cationic starch component. The artificial polymer component is a copolymer of acrylamide and at least one anionic monomer, and is characterized by an anionic content of 1-60 mole per cent. The artificial polymer component and the cationic starch component provide a composition with a charge density of 0.05-1 mEq/g when measured at pH 2.8 and from -0.2 to -3 mEq/g when measured at pH 7.0. The invention also relates to a method for the production of paper and cardboard, according to which a composition that provides strength in the dry state is diluted with water to obtain a solution of the composition with a final pH >3 and the resulting solution of the composition is added to the fibrous raw material before or after the addition of a cationic strengthening agent.

EFFECT: increased dry strength of the obtained products and improved dehydration efficiency are provided.

22 cl, 20 tbl, 9 ex