# US 9,751,955 B2 · Regeneration of cellulose > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,955 B2 - Document ID: US9751955B2 - Status: Granted - Kind: B2 - Application number: 14/450,362 - Filed: 2014-08-04 - Published: 2014-11-20 - Granted: 2017-09-05 - Earliest claimed: 2012-02-20 - Assignees: Re:Newcell AB - Applicants: Re:Newcell AB - Inventors: Mikael Lindström; Gunnar Henriksson - Web page: https://patentgrep.com/patent/US9751955B2 ## CPC - C08B 16/00: Regeneration of cellulose - D01D 1/02: Preparation of spinning solutions - D01F 2/00: Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof - D01F 2/06: from viscose - D21C 5/00: Other processes for obtaining cellulose, e.g. cooking cotton linters (obtaining fibres for spinning D01C); {Processes characterised by the choice of cellulose-containing starting materials} - C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21) - D01D: MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS - D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS - D21C: PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR ## Abstract A method for regeneration of a cellulose containing material, comprises the steps: a) exposing the cellulose containing material to oxygen with an alkali aqueous solution at a pH of at least 9, and a temperature of at least 20° C., b) dispersing the cellulose containing material in the alkali aqueous solution, wherein the temperature of the alkali aqueous solution is lowered below 15° C., and wherein the pH of the alkali aqueous solution is above 9, c) adding an organic solvent to the dispersion to precipitate cellulose, and d) separating the precipitated cellulose by at least one method selected from filtering and centrifugation. The method makes it possible to maintain a high alkali pH value in the process, which saves costs since the pH value does not have to be lowered by additions of various additives. The method makes it possible to remove non-cellulose parts of the cloth. ## Claims ### Claim 1 A method for regeneration of a cellulose containing material, said method comprising the sequential steps: a) exposing the cellulose containing material to oxygen or a gas mixture comprising oxygen together with an alkali aqueous solution at a pH of at least 9, and a temperature of at least 20° C., b) dispersing the cellulose containing material in the alkali aqueous solution to obtain a dispersion, wherein the temperature of the alkali aqueous solution is further lowered below 15° C., and wherein the pH of the alkali aqueous solution is above 9, c) adding at least one organic solvent to the dispersion to precipitate cellulose, and d) separating the precipitated cellulose from the remaining liquid by at least one method selected from filtering and centrifugation. ### Claim 2 (depends on 1) The method according to claim 1, wherein the dispersion of the cellulose containing material in the alkali aqueous solution is subjected to filtration after step b). ### Claim 3 (depends on 1) The method according to claim 1, wherein the at least one organic solvent added in step c) is miscible with water and has a boiling point which is lower than the boiling point of water. ### Claim 4 (depends on 1) The method according to claim 1, wherein the at least one organic solvent added in step c) is at least one selected from acetone, ethanol, isopropanol, and methanol. ### Claim 5 (depends on 1) The method according to claim 1, wherein the remaining liquid from step d) is separated into at least one stream comprising the at least one organic solvent, and at least one different stream comprising the alkali aqueous solution, wherein at least one of the streams is recycled, and wherein the separation is effected by at least one selected from a pressure lower than atmospheric pressure and a temperature higher than room temperature. ### Claim 6 (depends on 1) The method according to claim 1, wherein the separated precipitated cellulose from step d) is subjected to at least one selected from a pressure lower than atmospheric pressure and a temperature higher than room temperature to remove remaining at least one of the organic solvent and the alkali aqueous solution. ### Claim 7 (depends on 1) The method according to claim 1, wherein the separated precipitated cellulose from step d) is subjected to a wash with water. ### Claim 8 (depends on 1) The method according to claim 1, wherein the cellulose containing material is cloth. ### Claim 9 (depends on 1) The method according to claim 1, wherein the alkali aqueous solution comprises at least one metal hydroxide. ### Claim 10 (depends on 1) The method according to claim 1, wherein the alkali aqueous solution comprises at least 4 wt % of at least one of NaOH and KOH. ### Claim 11 (depends on 1) The method according to claim 1, wherein the temperature is below 10° C. in step b). ### Claim 12 (depends on 1) The method according to claim 1, wherein the temperature is below 4° C. in step b). ### Claim 13 (depends on 1) The method according to claim 1, wherein the pressure during step a) is 0.6 MPa or higher. ### Claim 14 (depends on 1) The method according to claim 1, wherein the separated precipitated cellulose from step d) is used as raw material for manufacture of regenerated cellulose. ### Claim 15 (depends on 1) The method according to claim 1, wherein the separated precipitated cellulose from step d) is mixed with a solution of cellulose xanthate for manufacture of a regenerated fiber. ### Claim 16 (depends on 1) The method according to claim 1, wherein the separated precipitated cellulose from step d) is reacted with CS2 to obtain cellulose xanthate for further manufacture of viscose.