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Hydro-Entangled Filter Material for Smoking Products

20230016316 · 2023-01-19

    Inventors

    Cpc classification

    International classification

    Abstract

    The invention relates to a filter material for a smoking product, comprising a nonwoven material, wherein the nonwoven material is hydro-entangled, the hydro-entangled nonwoven material contains min. 50% and max. 90% wood cellulose fibres, min. 10% and max. 50% fibres from regenerated cellulose and less than 30% non-natural polymers, in relation to the mass of the hydro-entangled nonwoven material, and together the amount of wood cellulose fibres and fibres from regenerated cellulose make up at least 70% of the mass of the hydro-entangled nonwoven material, and the hydro-entangled nonwoven material has a density of min 100 kg/m.sup.3 and max. 300 kg/m.sup.3 and a thickness of min. 100 μm and max. 1000 μm. The invention also relates to a segment with the filter material, a smoking product and a production method.

    Claims

    1. Filter material for a smoking article, which comprises a nonwoven, characterized in that the nonwoven is hydro-entangled, the hydro-entangled nonwoven contains at least 50% and at most 90% wood pulp fibers, at least 10% and at most 50% fibers from regenerated cellulose and less than 30% non-natural polymers, respectively with respect to the mass of the hydro-entangled nonwoven, and the amount of wood pulp fibers and fibers from regenerated cellulose together makes up at least 70% of the mass of the hydro-entangled nonwoven, and the hydro-entangled nonwoven has a density of at least 100 kg/m.sup.3 and at most 300 kg/m.sup.3 and a thickness of at least 100 μm and at most 1000 μm, wherein the thickness is measured in accordance with ISO 534:2011 and the density of the hydro-entangled nonwoven is determined by dividing the basis weight in accordance with ISO 536:2012 by the thickness in accordance with ISO 534:2011.

    2. Filter material according to claim 1, wherein the proportion of wood pulp fibers in the hydro-entangled nonwoven is at least 60% and at most 80% with respect to the mass of the hydro-entangled nonwoven.

    3. (canceled)

    4. Filter material according to claim 1, wherein the wood pulp fibers are at least partially formed by mercerized wood pulp fibers.

    5. (canceled)

    6. Filter material according to claim 1, wherein the wood pulp fibers are at least partially bleached.

    7. Filter material according to claim 1, wherein the proportion of fibers produced from regenerated cellulose in the hydro-entangled nonwoven is at least 20% and at most 45% with respect to the mass of the hydro-entangled nonwoven.

    8. (canceled)

    9. Filter material according to claim 1, wherein the sum of the amounts of wood pulp fibers and fibers from regenerated cellulose together makes up at least 80% of the mass of the hydro-entangled nonwoven.

    10. (canceled)

    11. Filter material according to claim 1, wherein the hydro-entangled nonwoven contains at least 5% and less than 30% staple fibers from cellulose acetate with respect to the mass of the hydro-entangled nonwoven.

    12. (canceled)

    13. Filter material according to claim 1, wherein the hydro-entangled nonwoven has a basis weight in accordance with ISO 536:2012 of at least 25 g/m.sup.2 and at most 150 g/m.sup.2.

    14. Filter material according to claim 1, wherein the thickness of the hydro-entangled nonwoven in accordance with ISO 534:2011 is at least 120 μm.

    15. (canceled)

    16. (canceled)

    17. Filter material according to claim 1, wherein a tensile strength with respect to the width of the hydro-entangled nonwoven in accordance with ISO 1924-2:2008 in at least one direction is at least 0.05 kN/m and at most 5 kN/m.

    18. Filter material according to claim 1, wherein the elongation at break of the hydro-entangled nonwoven in accordance with ISO 1924-2:2008 in at least one direction is at least 1% and at most 50%.

    19. Filter material according to claim 1, wherein the hydro-entangled nonwoven has an energy absorption in accordance with ISO 1924-2:2008 in at least one direction of at least 4 J/m.sup.2 and at most 500 J/m.sup.2.

    20. Filter material according to claim 1, wherein at least 90% of the mass of the filter material is formed by the hydro-entangled nonwoven.

    21. (canceled)

    22. Filter material according to claim 1, wherein the filter material comprises the hydro-entangled nonwoven and a substance selected from the group consisting of triacetin, propylene glycol, sorbitol, glycerol, polyethylene glycol, polyvinyl alcohol and tri-ethyl citrate or mixtures thereof.

    23. Segment of a smoking article, comprising the filter material and a wrapping material, wherein the filter material comprises a hydro-entangled nonwoven, and wherein the hydro-entangled nonwoven contains at least 50% and at most 90% wood pulp fibers, at least 10% and at most 50% fibers from regenerated cellulose and less than 30% non-natural polymers, respectively with respect to the mass of the hydro-entangled nonwoven, and the amount of wood pulp fibers and fibers from regenerated cellulose together make up at least 70% of the mass of the hydro-entangled nonwoven.

    24. (canceled)

    25. (canceled)

    26. Segment according to claim 23, wherein the segment is cylindrical with a diameter of at least-3 mm and at most 10 mm, and wherein the segment has a length of at least 4 mm and at most 40 mm.

    27. Segment according to claim 23, 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.

    28. Segment according to claim 23, with a density without the wrapping material of between 50 kg/m.sup.3 and 300 kg/m.sup.3.

    29. (canceled)

    30. Segment according to claim 23, the wrapping material of which has a basis weight in accordance with ISO 536:2012, of at least 20 g/m.sup.2 and at most 150 g/m.sup.2.

    31. (canceled)

    32. (canceled)

    33. Smoking article comprising a segment which contains an aerosol-forming material and a segment according to claim 23.

    34. Smoking article according to claim 33, wherein the smoking articles is a filter cigarette and the aerosol-forming material is or contains tobacco.

    35. Smoking article according to claim 33, wherein the smoking article is a smoking article wherein, during its intended use, the aerosol-forming material is only heated but not combusted.

    36. Process for the production of a hydro-entangled nonwoven, wherein the process comprises the following steps: A—producing an aqueous suspension comprising wood pulp fibers and fibers from regenerated cellulose, B—applying the suspension from step A to a running wire, C—de-watering the suspension through the running wire, to form a fiber web, D—transferring the fiber web from step C to a support wire, E—hydro-entangling the fiber web by means of at least one water jet directed onto the fiber web, in order to manufacture a hydro-entangled nonwoven and F—drying the hydro-entangled nonwoven, wherein the amount of wood pulp fibers and fibers from regenerated cellulose together makes up at least 70% of the mass of the solids in the suspension of step A, wherein the hydro-entangled nonwoven contains at least 50% and at most 90% wood pulp fibers, at least 10% and at most 50% fibers from regenerated cellulose and less than 30% non-natural polymers, respectively with respect to the mass of the finished hydro-entangled nonwoven, and wherein the hydro-entangled nonwoven has a density of at least 100 kg/m.sup.3 and at most 300 kg/m.sup.3 and a thickness of least 100 μm and at most 1000 μm, wherein the thickness is measured in accordance with ISO 534:2011 and the density of the hydro-entangled nonwoven is determined by dividing the basis weight in accordance with ISO 536:2012 by the thickness in accordance with ISO 534:2011.

    37. Process according to claim 36, wherein the hydro-entangled nonwoven produced by the process is suitable for the use in a filter material according to claim 1.

    38. Process according to claim 36, wherein the thickness of the hydro-entangled nonwoven in accordance with ISO 534:2011 is at least 120 μm and at most 800 μm.

    39. (canceled)

    40. (canceled)

    41. Process according to claim 36, wherein the proportion of wood pulp fibers in the hydro-entangled nonwoven is at least 60% and at most 80% with respect to the mass of the hydro-entangled nonwoven.

    42. (canceled)

    43. Process according to claim 36, wherein the proportion of fibers from regenerated cellulose in the hydro-entangled nonwoven is at least 20% and at most 45% with respect to the mass of the hydro-entangled nonwoven.

    44. Process according to claim 36, wherein the sum of the amounts of wood pulp fibers and fibers from regenerated cellulose together make up at least 80% of the mass of the hydro-entangled nonwoven.

    45. Process according to claim 36, wherein the aqueous suspension of step A has a solids content of at most 3.0%.

    46. Process according to claim 36, wherein the running web used in steps B and C is inclined upwards with respect to the horizontal in the running direction of the fiber web by an angle of at least 3° and at most 40°.

    47. (canceled)

    48. Process according to claim 36, wherein a plurality of water jets or is used to carry out the hydro-entangling in step E, wherein the water jets are arranged in at least one row orthogonal to the running direction of the fiber web.

    49. Process according to claim 36, wherein at least two water jets are used to carry out the hydro-entangling in step E, wherein the at least two water jets are directed onto different sides of the fiber web.

    50. (canceled)

    51. Filter material according to claim 1, wherein a content of pulp fibers from hemp, flax, jute, ramie, abacá, sisal or cotton is a total of at most 1% of the mass of the hydro-entangled nonwoven.

    52. Filter material according to claim 1, wherein the sum of the amounts of wood pulp fibers and fibers from regenerated cellulose together makes up at least 95% of the mass of the hydro-entangled nonwoven.

    53. Filter material according to claim 1, wherein the hydro-entangled nonwoven contains less than 1% non-natural polymers with respect to the mass of the hydro-entangled nonwoven.

    54. Filter material according to claim 1, wherein the hydro-entangled nonwoven has an air permeability in accordance with ISO 2965:2019 of between 35000 cm.sup.3/(cm.sup.2.Math.kPa.Math.min) and 45000 cm.sup.3/(cm.sup.2.Math.kPa.Math.min).

    55. Smoking article according to claim 39, wherein said segment according to claim 30 forms the segment of the smoking article located next to the mouth end.

    56. Process according to claim 36, wherein a proportion of pulp fibers from hemp, flax, jute, ramie, abacá, sisal or cotton is a total of at most 1% of the mass of the hydro-entangled nonwoven.

    57. Process according to claim 44, wherein the sum of the amounts of wood pulp fibers and fibers from regenerated cellulose together make up at least 95% of the mass of the hydro-entangled nonwoven.

    58. Process according to claim 44, wherein the aqueous suspension of step A has a solids content of at most 0.05%.

    Description

    BRIEF DESCRIPTION OF THE FIGURES

    [0075] FIG. 1 shows an arrangement by means of which the process according to the invention for the manufacture of the hydro-entangled nonwoven can be carried out.

    [0076] FIG. 2 shows the cross section of a segment according to the invention in comparison with a segment produced from cellulose acetate and a segment produced from paper.

    DESCRIPTION OF THE PREFERRED EMBODIMENTS

    [0077] Some preferred embodiments of the filter material, the segment for smoking articles, the smoking article and the process for the manufacture of the hydro-entangled nonwoven are described below.

    [0078] For the manufacture of the hydro-entangled nonwoven which is contained in the filter material according to the invention, the process shown in FIG. 1 was used.

    [0079] A suspension 1 produced from wood pulp fibers and fibers from regenerated cellulose was pumped from a head box 2 onto a running wire 3, inclined upwards with respect to the horizontal, and de-watered by vacuum boxes 9, so that a fiber web 4 was formed on the wire, the general direction of movement of which is indicated by arrow 10. The fiber web 4 was removed from wire 3 and transferred to a support wire 5 which was also running. In this, water jets 11 arranged in several rows orthogonal to the running direction of the fiber web 4 were directed onto the fiber web 4 from devices 6 in order to entangle the fibers and consolidate the fiber web 4 into a nonwoven. In a further step, water jets 12 were also directed onto the other side of the fiber web 4 by additional devices 7, in order to further entangle the emerging nonwoven. The still-wet nonwoven then ran through drying equipment 8 and was dried there.

    [0080] To manufacture the hydro-entangled nonwoven, mixtures of wood pulp fibers and Lyocell® fibers where used. Five different hydro-entangled nonwovens A to E were manufactured; their composition and properties are provided in Table 1. In this regard, the percentages in relation to Lyocell® fibers and wood pulp fibers indicate the amount of fibers with respect to the mass of the hydro-entangled nonwoven. The elongation at break and the energy absorption are each given in the machine direction (MD), i.e. in the direction indicated by arrow 10 in FIG. 1, and in the cross direction (CD) orthogonal thereto and lying in the plane of the fiber web 4.

    TABLE-US-00001 TABLE 1 Nonwoven A B C D E Filter Material A B C D E Lyocell ® Fibers % 20 20 40 40 40 Wood Pulp Fibers % 80 80 60 60 60 Basis Weight g/m.sup.2 40 60 80 120 50 Thickness μm 257 345 497 688 299 Density kg/m.sup.3 156 174 161 175 167 Tensile Strength kN/m 0.23 0.38 1.60 2.83 1.15 Elongation at Break MD % 6.6 7.0 12.4 20.0 15.5 Elongation at Break CD % 28.1 21.7 29.8 42.3 Energy Absorption MD J/m.sup.2 13.9 22.6 95.6 386.8 128.7 Energy Absorption CD J/m.sup.2 20.9 40.1 143.0 333.5

    [0081] The hydro-entangled nonwovens A to E were each used as filter material according to the invention A to E without adding further components.

    [0082] From filter material E according to the invention, three segments S1, S2 and S3 with different densities were manufactured, wherein each filter material was formed into a continuous tow with a diameter of 7.9 mm and wrapped with a wrapping material with a basis weight of 78 g/m.sup.2. The continuous tow was initially cut into rods with a length of 108 mm. The mean mass of the rods and the mean draw resistance of the rods, in accordance with ISO 6565:2015, were determined and the density without the wrapping material and the draw resistance per unit length were calculated therefrom. Next, the rods were cut into segments according to the invention with a length of 22 mm. Table 2 shows the data for the segments S1, S2 and S3. An exemplary calculation of the density of the segment is explained in more detail using segment S1.

    [0083] The measured mass of the 108 mm long rod of segment S1 was 0.743 g. The diameter was 7.9 mm. From this, ignoring the thickness of the wrapping material, this gave a volume for the rod of π/4×7.9.sup.2×108=5293 mm.sup.3

    [0084] The mass of the 27 mm wide and 108 mm long wrapping material with a basis weight of 78 g/m.sup.2 was 78×0.027×0.108=0.227 g.

    [0085] The density of the segment without the wrapping material is therefore (0.743−0.227)/5293=97.5 kg/m.sup.3.

    TABLE-US-00002 TABLE 2 Filter Material E E E Segment S1 S2 S3 Mass (108 mm) mg 743 911 1199 Density kg/m.sup.3 97.5 129.4 182.9 Draw Resistance mm WG/mm 1.76 4.16 11.12

    [0086] FIG. 2 shows photographs of the cross sectional area of segment S2 according to the invention as well as of two comparable segments from cellulose acetate (CA) and paper (PA). For the segment produced from paper, the coarse structure of the cross-sectional area is clearly visible, while the segment produced from cellulose acetate exhibits a very fine structure. The segment S2 according to the invention is substantially closer to that of cellulose acetate (CA) in its optical appearance and thus results in a much more acceptable optical impression than the segment produced from paper (PA).

    [0087] From each of the segments S1, S2 and S3 according to the invention, non-ventilated smoking articles R1, R2 and R3 according to the invention with a length of 83 mm were manufactured, which contained a segment with tobacco and a filter segment. The filter segment was formed by one of each of the segments S1, S2 and S3 according to the invention. The smoking articles R1, R2 and R3 were smoked in accordance with the method specified in ISO 3308 and the amount of tar, nicotine and water in the smoke were determined. An identical smoking article, in which the filter was formed by a conventional filter segment from cellulose acetate, was smoked according to the same method. A comparison of the amount of tar, nicotine and water showed that the filter segments S1, S2 and S3 agree well with a filter segment produced from cellulose acetate having regard to their filtration efficiency.

    [0088] In addition, the draw resistances of the segments S1, S2 and S3 were in an advantageous range for a smoking article and can easily be adjusted to requirements by the density of the segment, even for a given composition of the segments.

    [0089] The biodegradability of the segments S1, S2 and S3, as well as of the smoking articles R1, R2 and R3 produced therefrom was not separately tested, because this is given by the components used.

    [0090] This shows that filter materials according to the invention, which contain a hydro-entangled nonwoven, offer advantages with respect to biodegradability and optical appearance compared with filter materials which are known in the art, without being limited in their function as filter, and furthermore can be manufactured industrially and inexpensively from readily available raw materials.