# US 10,767,312 B2 · Method for producing paper, board or the like > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,767,312 B2 - Document ID: US10767312B2 - Status: Granted - Kind: B2 - Application number: 16/062,710 - Filed: 2016-12-15 - Published: 2019-10-10 - Granted: 2020-09-08 - Earliest claimed: 2015-12-15 - Assignees: Kemira Oyj - Applicants: Kemira Oyj - Inventors: Kaisa Karisalmi; Tom Lundin; Mikko Virtanen; Antti Laukkanen; Jason McKee - Web page: https://patentgrep.com/patent/US10767312B2 ## CPC - D21H 11/18: Highly hydrated, swollen or fibrillatable fibres - D21H 11/12: Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse - D21H 17/21: of natural origin; Derivatives thereof - D21H 17/33: Synthetic macromolecular compounds - D21H 21/18: Reinforcing agents - D21H 21/20: Wet strength agents - C08L 1/02: Cellulose; Modified cellulose - D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract The invention relates to a method for producing paper, board or the like. The method comprises obtaining a thick stock comprising cellulose fibres, forming a fibrous web and drying of drying the fibrous web. A strength agent system, which comprises at least one synthetic or natural polymer, or their mixture, and microfibrillated parenchymal cellulose material originating from non-wood sources, is added to the thick stock. The invention relates also to paper or board produced by the method. ## Claims ### Claim 1 A method for producing paper or board, comprising: obtaining a thick stock comprising cellulose fibres; forming a fibrous web; and drying the fibrous web, wherein a strength agent system, comprising at least one synthetic or natural polymer or their mixture and a microfibrillated parenchymal cellulose material originating from non-wood sources is added to the thick stock, and wherein a cationic retention polymer, which is a cationic polyacrylamide having an average molecular weight of 4,000,000-18,000 000 Da is added to the stock after the addition of the strength agent system. ### Claim 2 (depends on 1) The method according to claim 1, wherein the microfibrillated parenchymal cellulose material originates from vegetables; fruits; cellulose pith; and mixtures thereof. ### Claim 3 (depends on 2) The method according to claim 2, wherein the microfibrillated parenchymal cellulose material originates from vegetables selected from sugar beet pulp, potato pulp, cassava pulp, sweet potato and any mixtures thereof. ### Claim 4 (depends on 1) The method according to claim 1, wherein the microfibrillated parenchymal cellulose material is obtained by mechanical treatment, without preceding treatment steps, which are selected from oxidation, extraction and/or washing. ### Claim 5 (depends on 4) The method according to claim 4, wherein the mechanical treatment is homogenization. ### Claim 6 (depends on 1) The method according to claim 1, wherein the microfibrillated parenchymal cellulose material has: a Brookfield viscosity of at least 10 Pas, measured at concentration of 1.0 weight-% at 100 rpm shear rate, and/or a turbidity value less than 1000 NTU, measured at 0.1 weight-% concentration, and/or a net charge in a range of −0.001-1.99 meq/g, at pH 7.5. ### Claim 7 (depends on 1) The method according to claim 1, wherein the Brookfield viscosity of the microfibrillated parenchymal cellulose material is in a range of 500 2000 Pas. ### Claim 8 (depends on 1) The method according to claim 1, wherein the turbidity of the microfibrillated parenchymal cellulose material may be in a range 375-525 NTU. ### Claim 9 (depends on 1) The method according to claim 1, wherein the strength agent system is added in such amount that the microfibrillated parenchymal cellulose material is added in amount of 1-100 kg, given as dry per ton of dry solids of the fibre stock. ### Claim 10 (depends on 9) The method according to claim 9, wherein the strength agent system is added in such amount that the microfibrillated parenchymal cellulose material is added in amount of 5-70 kg. ### Claim 11 (depends on 1) The method according to claim 1, wherein the strength agent system comprises 50-99.9 weight-%, of microfibrillated parenchymal cellulose material, calculated from the dry solids content. ### Claim 12 (depends on 11) The method according to claim 11, wherein the strength agent system comprises 70-99.9 weight-% of microfibrillated parenchymal cellulose material, calculated from the dry solids content. ### Claim 13 (depends on 1) The method according to claim 1, wherein that the strength agent system comprises a natural polymer, which is selected from a group consisting of cationic or amphoteric starch, chitin, guargum, carboxymethyl cellulose, and any mixture thereof. ### Claim 14 (depends on 1) The method according to claim 1, wherein the strength agent is a synthetic polymer selected from cationic polyacrylamide (C-PAM), glyoxalated poly-acrylamide (G-PAM), amphoteric polyacrylamide, polydiallyldimethylammonium chloride (poly-DADMAC), polyacrylic amide (PARE), polyvinyl amine (PVAm), polyethylene oxide (PEO), polyethyleneimine (PEI) or a mixture of two or more of these polymers. ### Claim 15 (depends on 14) The method according to claim 14, wherein the average molecular weight of the synthetic polymer is in a range 100,000-20,000,000 g/mol. ### Claim 16 (depends on 14) The method according to claim 14, wherein the synthetic polymer is a cationic synthetic polymer which has a charge density of 0.5-2 meq/g. ### Claim 17 (depends on 14) The method according to claim 14, wherein the synthetic polymer is a cationic synthetic polymer which is a copolymer of methacrylamide or acrylamide and at least one cationic monomer. ### Claim 18 (depends on 1) The method according to claim 1, wherein the cationic retention polymer is cationic polyacrylamide having an average molecular weight of 4,000,000 12,000,000 Da and/or having a charge density of 0.2-2.5 meq/g. ### Claim 19 (depends on 1) The method according to claim 1, wherein the stock comprising cellulose fibres is obtained by using furnish from kraft pulping, chemithermomechanical pulping or by repulping recycled fibres. ### Claim 20 (depends on 1) A paper or board product, having a density in a range of 150-800 kg/m3, produced by a method according to claim 1.