Filter material for segments for smoking articles with reduced creep tendency

Abstract

Shown is a filter material for manufacturing a segment for a smoking article, wherein the filter material is hydroentangled and contains at least 50% and at most 100% cellulose fibers, each with respect to the mass of the filter material, wherein the filter material has a basis weight of at least 15 g/m 2 and at most 60 g/m 2 , wherein the thickness of one layer of the filter material, measured in accordance with ISO 534:2011, is at least 25 μm and at most 400 μm, and wherein the filter material has a creep tendency in the thickness direction of at most 10%, wherein the creep tendency is the relative decrease in the thickness of 5 layers of the filter material, measured in accordance with ISO 534:2011, within 20 s after the start of the thickness measurement.

1 . Filter material for manufacturing a segment for a smoking article, wherein the filter material is hydroentangled and contains at least 50% and at most 100% cellulose fibers, each with respect to the mass of the filter material,
 wherein the filter material has a basis weight of at least 15 g/m 2  and at most 60 g/m 2 ,   wherein the thickness of one layer of the filter material, measured in accordance with ISO 534:2011, is at least 25 μm and at most 400 μm, and wherein the filter material has a creep tendency in the thickness direction of at most 10%, wherein the creep tendency is the relative decrease in the thickness of 5 layers of the filter material, measured in accordance with ISO 534:2011, within 20 s after the start of the thickness measurement.   
     
     
         2 . Filter material according to  claim 1 , in which the proportion of cellulose fibers in the filter material is at least 70% and at most 95%, each with respect to the mass of the filter material. 
     
     
         3 . Filter material according to  claim 1 , in which the cellulose fibers are formed by pulp fibers, by fibers from regenerated cellulose or mixtures thereof. 
     
     
         4 . (canceled) 
     
     
         5 . Filter material according to  claim 3 , in which the proportion of fibers from regenerated cellulose is at least 5% and at most 50% with respect to the mass of the filter material. 
     
     
         6 . (canceled) 
     
     
         7 . Filter material according to  claim 1 , with a basis weight of at least 20 g/m 2  and at most 50 g/m 2 . 
     
     
         8 . Filter material according to  claim 1 , wherein the filter material has a creep tendency in the thickness direction of at least 1% and at most 5%. 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . Filter material according to  claim 1 , which contains at least one substance selected from the group consisting of triacetin, propylene glycol, sorbitol, glycerol, polyethylene glycol, polypropylene glycol, polyvinyl alcohol and triethyl citrate, or a mixture of two or more of the at least one substances. 
     
     
         12 . Filter material according to  claim 1 , in which at least a portion of the cellulose fibers is loaded with a filler, wherein the filler is formed by calcium carbonate particles. 
     
     
         13 . Filter material according to  claim 1 , in which the thickness of one layer of the filter material, measured in accordance with ISO 534:2011, is at least 30 μm and at most 350 μm. 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . Segment for a smoking article, comprising a filter material and a wrapper material, wherein the filter material contains at least 50% and at most 100% cellulose fibers, each with respect to the mass of the filter material,
 wherein the filter material has a basis weight of at least 15 g/m 2  and at most 60 g/m 2 ,   wherein the thickness of one layer of the filter material, measured in accordance with ISO 534:2011, is at least 25 μm and at most 400 μm, and wherein the filter material has a creep tendency in the thickness direction of at most 10%, wherein the creep tendency is the relative reduction of thickness of 5 layers of the filter material, measured in accordance with ISO 534:2011, within 20 s after the start of the thickness measurement.   
     
     
         17 . Segment according to  claim 16 , in which the filter material has one or more of the additional features that are defined in  claim 2 . 
     
     
         18 . Segment according to  claim 16 , wherein the segment is cylindrical with a diameter of at least 4 mm and at most 9 mm, and/or wherein the segment has a length of at least 6 mm and at most 35 mm. 
     
     
         19 . Segment according to  claim 16 , wherein the draw resistance of the segment in accordance with ISO 6565:2015 per unit length of the segment is at least 1 mmWG/mm and at most 12 mmWG/mm. 
     
     
         20 . (canceled) 
     
     
         21 . Segment according to  claim 16 , in which the wrapper material has a basis weight in accordance with ISO 536:2019 of at least 30 g/m 2  and at most 130 g/m 2 . 
     
     
         22 . Process for manufacturing a segment according to  claim 16 , in which the filter material according to  claim 1  is crimped or pleated, a continuous tow of crimped or pleated filter material is formed and the tow of crimped or pleated filter material is wrapped with a wrapper material and the wrapped tow is cut into individual rods of a defined length. 
     
     
         23 . Smoking article comprising a segment which contains an aerosol-forming material, and a segment according to  claim 16 . 
     
     
         24 . Smoking article according to  claim 23 , wherein the smoking article is a filter cigarette and the aerosol-forming material is or contains tobacco. 
     
     
         25 . Smoking article according to  claim 23 , wherein the smoking article is a smoking article in which, during its intended use, the aerosol-forming material is only heated but not burned, wherein the aerosol-forming material comprises a material selected from the group consisting of tobacco, reconstituted tobacco, nicotine, glycerol, propylene glycol or mixtures thereof. 
     
     
         26 . Smoking article according to  claim 25 , wherein the aerosol-forming material is present in liquid form and located in a corresponding container in the smoking article. 
     
     
         27 . Process for manufacturing a filter material, wherein the process comprises the following steps:
 A—providing a fiber web comprising cellulose fibers,   B—hydroentangling the fiber web by water jets directed onto the fiber web, in order to manufacture a hydroentangled fiber web,   C—drying the hydroentangled fiber web,   wherein in step A, the amount or the proportion of cellulose fibers is selected such that after drying in step C, the filter material contains at least 50% and at most 100% cellulose fibers with respect to the mass of the filter material, and   wherein in step B, the number of water jets, the pressure of the water jets or the shape of the openings from which the water jets exit are chosen such that after drying in step C, the filter material has a creep tendency in the thickness direction of at most 10%,   wherein the creep tendency is the relative decrease in the thickness of 5 layers of the filter material, measured in accordance with ISO 534:2011, within 20 s after the start of the thickness measurement, and   after drying in step C, the filter material has a basis weight of at least 15 g/m 2  and at most 60 g/m 2  and the thickness of one layer of the filter material, measured in accordance with ISO 534:2011, is at least 25 μm and at most 400 μm.   
     
     
         28 . Process according to  claim 27 , in which at least a portion of the nozzles, from which the water jets exit in step B is shaped as round holes in a nozzle strip, wherein the diameter of the holes in the nozzle strip facing the filter material is greater than the diameter of the holes facing away from the filter material and at most twice the diameter of the holes facing away from the filter material. 
     
     
         29 . Process according to of  claim 27 , wherein the filter material manufactured according to this process is a filter material according to  claim 1 . 
     
     
         30 . Process according to  claim 27 , in which the provision of a fiber web in step A comprises spinning a plurality of cellulose fibers, wherein the cellulose fibers are formed by filaments of regenerated cellulose and wherein at least 90% of the mass of the filter material after drying in step C is formed by the filaments of regenerated cellulose. 
     
     
         31 . Process according to  claim 27 , in which the provision of a fiber web in step A comprises the following steps A1 to A4:
 A1—producing an aqueous suspension comprising cellulose fibers,   A2—applying the suspension from step A1 to a running wire,   A3—de-watering the suspension through the running wire to form a fiber web,   A4—transferring the fiber web from step A3 onto a support wire.   
     
     
         32 . Process according to  claim 31 , in which the aqueous suspension in step A1 has a solids content of at most 0.2%. 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . (canceled) 
     
     
         36 . Process according to claim  35 , in which the hydroentangling in step B is carried out by at least four rows of water jets directed onto the fiber web, wherein at least two rows of water jets act on each of the two sides of the fiber web. 
     
     
         37 . Process according to of  claim 27 , which comprises a further step in which one or more additives are applied to the fiber web, wherein the one or more additives is or are selected from the group consisting of alkyl ketene dimers (AKD), acid anhydrides, alkenyl succinic acid anhydrides (ASA), polyvinyl alcohol, waxes, fatty acids, starch, starch derivatives, carboxy methyl cellulose, alginates, chitosan, wet strength agents and substances for adjusting the pH, organic or inorganic acids or bases, and mixtures thereof. 
     
     
         38 . (canceled) 
     
     
         39 . Process according to  claim 27 , in which the one or more additives are applied between the steps B and C, or after step C, followed by a further step of drying the fiber web. 
     
     
         40 . (canceled) 
     
     
         41 . A smoking article of  claim 23 , wherein said segment according to  claim 16  is the segment of the smoking article located closest to the mouth end.