METHOD FOR PRODUCING HYDROPHOBIC PAPER Russian patent published in 2022 - IPC D21H17/23 D21H17/29 D21H17/66 D21H21/16 

FIELD: paper industry.

SUBSTANCE: group of inventions relates to a method for producing hydrophobic paper, the use of a gluing additive based on depolymerized lignin, and hydrophobic paper obtained by this method. To a suspension of lignocellulose mass, in a wet part of the paper production process, the following is added: (i) a gluing additive including a mixture of depolymerized lignin with an average molecular weight of 400-2500 g/mol with an additional component selected from cationic polysaccharide and/or gelatin, (ii) aluminum salts, and (iii) optionally, a retaining additive. Depolymerized lignin is added in the amount from 0.5 to 20 kg/t of dry fibrous mass per the dry weight of depolymerized lignin. Aluminum salt is added in the amount corresponding to at least 0.01 kg Al/t of dry fibrous mass. Hydrophobic paper produced by this method contains depolymerized lignin with an average molecular weight of 400-2500 g/mol, in particular 400-1500 g/mol, 400-1300 g/mol, 400-1000 g/mol or 500-800 g/mol. As the only gluing additive in the production of hydrophobic paper, a mixture of depolymerized lignin is used with an average molecular weight of 400-2500 g/mol, in particular 400-1500 g/mol, 400-1300 g/mol, 400-1000 g/mol or 500-800 g/mol with an additional component selected from cationic polysaccharide and/or gelatin.

EFFECT: elimination of the use of traditional hydrophobic agents such as ASA, AKD and/or rosin in the production of hydrophobic paper products, and improvement of properties of such paper products are ensured.

16 cl, 5 dwg, 4 tbl