METHOD FOR MANUFACTURING SINGLE-LAYER OR MULTI-LAYER PAPER Russian patent published in 2023 - IPC D21H23/50 D21F11/04 D21H17/34 D21H17/37 D21H21/20 D21H27/30 

FIELD: packaging.

SUBSTANCE: group of inventions can be used in production of packaging paper or cardboard. A method for making dried single-layer paper includes pressing the first fibrous sheet made from an aqueous fibrous suspension to produce a partially dehydrated fibrous sheet. In the case of multilayer paper production, first and second fibrous sheets are produced, which are joined and pressed to form a partially dehydrated laminate sheet. The solution or suspension is then sprayed onto at least one side of the partially dehydrated sheet or partially dehydrated laminate sheet. The sprayable solution or sprayable suspension contains water and a water-soluble polymer P obtained by polymerization of the monomer of formula I

where R¹ is H or C1-C6 alkyl, and one or more ethylenically unsaturated monomers other than the monomer of formula I. The treated sheets are dehydrated by applying heat to produce dried single-layer or multi-layer paper. A paper making machine is also proposed.

EFFECT: group of inventions makes it possible to increase the internal strength of paper.

10 cl, 6 tbl