METHOD FOR PRODUCING CELLULOSE HYDROGEL COMPOSITE Russian patent published in 2023 - IPC C08J3/02 D21H11/10 A61F13/15 A61L15/60 

FIELD: pulp and paper industry.

SUBSTANCE: invention relates to a method for manufacturing a cellulose hydrogel composite, including the operations of preparing cellulose and superabsorbent material, manufacturing the composite at a ratio of cellulose mass of 90-95 wt.% and superabsorbent material of 5-10 wt.%, characterized in that papermaking technology is used, including operations of preparing cellulose pulp and preparing superabsorbent material, composing the composition of paper pulp and obtaining a cellulose hydrogel composite on a paper making machine (PM), wherein: preparation of pulp consists of dissolving commercial sulphate bleached softwood pulp, or sulphate bleached softwood pulp and sulphate bleached hardwood pulp in water cellulose, or bleached kraft softwood pulp and chemithermomechanical bleached wood pulp, or bleached kraft softwood pulp and bleached kraft hardwood pulp and chemithermomechanical bleached wood pulp at a concentration of 3-12 wt.%; fibrillating grinding of bleached softwood sulphate pulp up to 18-30°SсhR; preparation of superabsorbent material, for which hydrogel (superabsorbent) is used, consists in the fact that the calculated mass of air-dry powdered hydrogel with a particle size of 50-300 mcm is added to a tank with a stirrer and an appropriate volume in such a way as to obtain a suspension of hydrogel 1 -10 wt.%, mix and stand, optimal holding time is 10-15 minutes; the composition of the paper pulp of the cellulose hydrogel composite along the fibres is made up in a composition pool; the composition includes: 1) ground sulphate bleached softwood cellulose 50-100 wt.% with a grinding degree of 18-30°SchR, concentration 3-12%; unground sulphate bleached hardwood pulp 0-50 wt.%, concentration 3-12%, or 2) ground sulphate bleached softwood pulp 70-100 wt.% with a grinding degree of 18-30°SchR, concentration 3-12%; chemical thermomechanical bleached wood pulp 0-30 wt.%, concentration 3-12%, or 3) ground bleached sulphate softwood pulp 20-50 wt.% with a grinding degree of 18-30°SchR, concentration 3-12%; unground sulphate bleached hardwood pulp 0-50 wt.%, concentration 3-12%; chemical thermomechanical bleached wood pulp 0-30 wt.%, concentration 3-12%, then the mass is sent to the machine pool, in which it is diluted to a concentration of 2.5-3.0 wt.%; dosing of the prepared hydrogel into the paper pulp is carried out directly into the paper pulp in front of the mixing pump of the paper pulp with recycled water and feeding it into the head box of the paper machine; dilution of the mass is carried out to a working concentration in the range of 0.3-0.7 wt.%; the hydrogel is dosed at a rate of 5.0-10.0 wt.% by weight of the composite; the composite is produced on a paper machine, going through all the processes of papermaking technology; casting and dehydration of the cellulose hydrogel composite to a dryness of 16-18 wt.% occurs in sheet form on the mesh part of the paper machine; passing through the press part of the paper machine, the wet sheet is dehydrated to a dryness of 40-50 wt.%; then in the drying part the wet sheet is dried until the final dryness of the composite is 85-90 wt.%; the dried composite is wound into vestibules and cut into rolls of specified formats on a rewinder-cutting machine.

EFFECT: increased absorption of water and aqueous solutions, increased mechanical strength, reduced thickness, increased density, elimination of the stages of fluffing and adding superabsorbent material during subsequent processing of the composite, and, through the use of papermaking technology, intensive surface interaction of cellulose fibrous semi-finished products (cellulose, wood pulp) with the superabsorbent material with formation of physicochemical and chemical bonds that form and secure the structure of the cellulose matrix with a uniformly distributed superabsorbent.

1 cl, 5 ex