# US 8,464,728 B2 · Biodegradable composites > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,464,728 B2 - Document ID: US8464728B2 - Status: Granted - Kind: B2 - Application number: 12/893,572 - Filed: 2010-09-29 - Published: 2011-04-28 - Granted: 2013-06-18 - Earliest claimed: 2009-10-23 - Assignees: Innovia Films Limited - Applicants: Colin Marshall; Jamie Moffat - Inventors: Colin Marshall; Jamie Moffat - Web page: https://patentgrep.com/patent/US8464728B2 ## CPC - A24D 3/068: {Biodegradable or disintegrable} - A24D 3/10: of cellulose or cellulose derivatives - B29C 48/05: Filamentary, e.g. strands - D01F 2/00: Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof - D01F 2/02: from solutions of cellulose in acids, bases or salts - D01F 2/28: from organic cellulose esters or ethers, e.g. cellulose acetate - Y10T 442/30: Woven fabric [i.e., woven strand or strip material] - A24D: CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES OF CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention concerns a biodegradable cigarette filter tow comprising composite filaments of cellulose and cellulose acetate, and a process for making such a filter tow comprising providing a solution dope comprising a blend of cellulose and cellulose acetate in an ionic liquid or in N-methylmorphilone-N-oxide (NMMO), and spinning casting the blend into a protic solvent to generate fibers or films, and converting the fibers or films into cigarette filter tow. The invention also concerns cigarette filters and cigarettes made from such a filter tow. ## Claims ### Claim 1 A biodegradable cigarette filter tow comprising composite filaments of cellulose and cellulose acetate, wherein the cigarette filter tow has a moisture content of at least 2% w/w and wherein the filter tow is prepared so as to exhibit a rate of biodegradation in an anaerobic environment exceeding the rate of biodegradation in an anaerobic environment corresponding to otherwise equivalent fibers spun from cellulose alone or from a cellulose acetate alone. ### Claim 2 (depends on 1) The filter tow according to claim 1 further comprising one or more further thermoplastic materials. ### Claim 3 (depends on 2) The filter tow according to claim 2, wherein the further thermoplastic material is selected from one or more of PHB, PHVB, polyacrylonitrile (PAN), poly-2-hydroxyethylmethylacrylate (PHEMA), polyvinylalcohol (PVA), polyaniline and polyethylene glycol. ### Claim 4 (depends on 1) The filter tow according to claim 1, wherein the weight ratio of cellulose to cellulose acetate is from 10:90 to 90:10. ### Claim 5 (depends on 4) The filter tow according to claim 4, wherein the ratio of cellulose to cellulose acetate is from 20:80 to 80:20. ### Claim 6 (depends on 5) The filter tow according to claim 5, wherein the ratio of cellulose to cellulose acetate is from 30:70 to 70:30. ### Claim 7 (depends on 1) The filter tow according to claim 1 further comprising one or more plasticisers. ### Claim 8 (depends on 1) The filter tow according to claim 1 further comprising a catalyst promoting oxidative degradation of the filter tow. ### Claim 9 (depends on 1) The filter tow according to claim 1 further comprising one or more lubricants to reduce electrostatic charge on the tow. ### Claim 10 (depends on 1) A cigarette filter comprising the cigarette filter tow according to claim 1 encased in a tipping wrapper. ### Claim 11 (depends on 10) The cigarette comprising a smokable substance and a cigarette filter according to claim 10. ### Claim 12 (depends on 1) The filter tow according to claim 1, wherein the cigarette filter tow has a moisture content of at least 10% w/w. ### Claim 13 (depends on 1) The filter tow according to claim 1, wherein the cigarette filter tow has a moisture content of at least 5% w/w. ### Claim 14 A process for manufacturing a cigarette filter tow comprising composite filaments of cellulose and cellulose acetate, wherein the cigarette filter tow is prepared so as to exhibit a rate of biodegradation in an anaerobic environment exceeding the rate of biodegradation in an anaerobic environment corresponding to otherwise equivalent fibers spun from cellulose alone or from a cellulose acetate alone, said process comprising providing a solution dope comprising a blend of cellulose and cellulose acetate in an ionic liquid and spinning or casting the blend into a protic solvent to generate fibres or films, and converting the fibres or films into cigarette filter tow. ### Claim 15 (depends on 14) The process according to claim 14, wherein the dope further comprises an aprotic solvent to aid dissolution of the cellulose and/or cellulose acetate. ### Claim 16 (depends on 15) The process according to claim 15, wherein the aprotic solvent comprises one or more of DMSO, DMF, THF or dioxane. ### Claim 17 (depends on 16) The process according to claim 16, wherein the aprotic solvent comprises about 80% DMSO. ### Claim 18 (depends on 14) The process according to claim 14, wherein the dope comprises a total solids content of up to about 20% w/w. ### Claim 19 (depends on 14) The process according to claim 14, wherein the dope comprises a total solids content of up to about 10% w/w. ### Claim 20 (depends on 14) The process according to claim 14, wherein the ionic liquid is selected from the group consisting of 1-butyl-3-methylimidazolium chloride (BMIM-Cl) 1-butyl-3-methylimidazolium acetate (BMIM-Ac) and 1-ethyl-3-methylimidazolium acetate (EMIM-Ac). ### Claim 21 A biodegradable cigarette filter tow comprising crimped composite filaments of cellulose and cellulose acetate, wherein the filter tow comprises has a moisture content between about 10% to 50% w/w.