STRUCTURED FILTER MATERIAL FOR NICOTINE DELIVERY PRODUCTS

Abstract

A filter material is described for manufacturing a nicotine delivery product, 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 25 g/m.sup.2 and at most 60 g/m.sup.2, and wherein the filter material has a structure that is characterized in that it provides the filter material with a transparency that, measured in accordance with DIN 53147:1993-01, is at least 45% and at most 70%. Furthermore, a segment comprising a filter material for a nicotine delivery product, a smoking article which comprises such a segment, an oral nicotine delivery product, and a process for the manufacture of the filter material are described.

Claims

1. Filter material for manufacturing a nicotine delivery product, 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 25 g/m.sup.2 and at most 60 g/m.sup.2, and wherein the filter material has a structure that is characterized in that it provides the filter material with a transparency which, measured in accordance with DIN 53147:1993-01, is at least 45% and at most 70%.

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, fibers from regenerated cellulose or mixtures thereof.

4. (canceled)

5. Filter material according to claim 3, in which the proportion of fibers produced from regenerated cellulose is least 15% and at most 40% with respect to the mass of the filter material.

6. (canceled)

7. Filter material according to claim 1, the basis weight of which, in accordance with ISO 536:2012 is at least 28 g/m.sup.2 and at most 55 g/m.sup.2.

8. Filter material according to claim 1, the transparency of which, measured in accordance with DIN 53147:1993-01 is at least 50% and at most 66%.

9. Filter material according to claim 1, in which said structure comprises a plurality of holes in the filter material, wherein at least 90% of the holes have an area of less than 10 mm.sup.2.

10. Filter material according to claim 1, which further contains one or more additional components selected from the group consisting of alkyl ketene dimers (AKD), alkenyl succinic acid anhydrides (ASA), fatty acids, starch, starch derivatives, carboxy methyl cellulose, alginates, wet strength agents, or substances for the adjustment of the pH, organic or inorganic acids or bases, or burn additives selected from the group consisting of citrates, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, ?-hydroxy caprylates, phosphates, polyphosphates, chlorides and hydrogen carbonates, and mixtures thereof.

11. Filter material according to claim 1, which further contains one or more substances selected from the group consisting of triacetin, propylene glycol, sorbitol, glycerol, polyethylene glycol, polypropylene glycol, polyvinyl alcohol and triethyl citrate.

12. Filter material according to claim 1, the thickness of which, measured in accordance with ISO 534:2011 is at least 70 ?m and at most 1000 ?m.

13. Filter material according to claim 1, the tensile strength with respect to width of which, measured 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.

14. Filter material according to claim 1, the elongation at break of which, measured in accordance with ISO 1924-2:2008 in at least one direction, is at least 3% and at most 40%.

15. Segment for a nicotine delivery product, wherein the nicotine delivery product is a smoking article, comprising a filter material according to claim 1 and a wrapping material, which wraps the filter material.

16. Segment according to claim 15, wherein the segment is in the shape of a cylinder with a circular base area, wherein the circular base area has a diameter of at least 5 mm and at most 8 mm.

17. Segment according to claim 1, which has a length of at least 4 mm and at most 40 mm.

18. Segment according to claim 15, the draw resistance per length of the segment of which, measured in accordance with ISO 6565:2015, is at least 1 mmWG/mm and at most 12 mmWG/mm.

19. Segment according to claim 15, in which the wrapping material is a paper or a film.

20. Segment according to claim 15, in which the wrapping material has a basis weight of at least 20 g/m.sup.2 and at most 150 g/m.sup.2.

21. Smoking article, comprising a segment, which contains an aerosol-forming material, and a segment according to claim 15.

22. Smoking article according to claim 21, in which the segment according to claim 15 a segment located next to the mouth end of the smoking article.

23. Smoking article according to claim 21, in which the smoking article is a filter cigarette and the aerosol-forming material is tobacco.

24. Smoking article according to claim 21, during the intended use of which the aerosol-forming material is only heated but not burned, and the aerosol-forming material comprises tobacco, reconstituted tobacco, nicotine, glycerol, propylene glycol or mixtures of two or more of these components.

25. Smoking article according to claim 21, in which the wrapping material of said segment according to claim 15 is at least partially transparent or has holes and the filter material has a transparency, measured in accordance with DIN 53147:1993-01, of at least 50%.

26. Oral nicotine delivery product comprising a pouch which is formed by a filter material according to claim 1 and contains a nicotine-containing material, wherein the filter material has a transparency, measured in accordance with DIN 53147:1993-01, of at least 50% and at most 70%.

27. Process for the manufacture of a filter material, which comprises the steps A to D: A providing a fiber web comprising cellulose fibers, B hydroentangling the fiber web by at least one water jet directed onto the fiber web in order to manufacture a hydroentangled fiber web, C generating a structure in the hydroentangled fiber web, D drying the hydroentangled fiber web, wherein the amount of cellulose fibers in step A is selected such that after drying in step D, the filter material contains at least 50% and at most 100% cellulose fibers with respect to the mass of the filter material, and after drying in step D, the filter material has a basis weight of at least 25 g/m.sup.2 and at most 60 g/m.sup.2, and after drying in step D, the filter material has a structure that is characterized in that it provides the filter material with a transparency, measured in accordance with DIN 53147:1993-01, of at least 45% and at most 70%, and the generation of a structure in step C is carried out by directing at least one water jet onto the fiber web while the fiber web is supported by a surface that has a plurality of prominences.

28. Process according to claim 27, wherein step A comprises spinning a plurality of cellulose fibers, wherein the cellulose fibers are formed by filaments of regenerated cellulose and wherein after drying in step D, at least 90% of the mass of the filter material is formed by filaments of regenerated cellulose.

29. Process according to claim 27, wherein step A comprises the steps A1 to A4: A1 manufacturing an aqueous suspension comprising cellulose fibers, A2 applying the suspension from step A to a running wire, A3 de-watering the suspension through the running wire in order to form a fiber web, and A4 transferring the fiber web from step A3 to a support wire.

30. Process according to claim 29, in which the aqueous suspension in step A1 has a solid content of at most 0.2%.

31. (canceled)

32. (canceled)

33. Process according to claim 27, in which a plurality of water jets is used in order to carry out the hydroentangling in step B, wherein the water jets are arranged in at least one row transverse to the running direction of the fiber web.

34. Process according to claim 27, a in which the hydroentangling in step B is carried out by at least two water jets directed onto the fiber web, wherein the at least two water jets act from different sides of the fiber web.

35. Process according to claim 27, in which the fiber web in step C is supported by a cylinder, on the surface of which a plurality of prominences is located.

36. Process according to claim 27, in which the area of each prominence, projected onto the surface that supports the fiber web in step C, is at least 0.1 mm.sup.2 and at most 15 mm.sup.2.

37. Process according to claim 27, in which the drying in step D is at least partially carried out by contact with hot air, by infra-red radiation or by microwave radiation.

38. Process according to claim 27, in which after drying in step D, the filter material is a filter material according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0081] FIG. 1 shows an arrangement by means of which the process according to the invention for the manufacture of the hydroentangled filter material can be carried out.

[0082] FIG. 2 shows, by way of example, filter materials according to the invention and not according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS, AND SOME COMPARATIVE EXAMPLES

[0083] Some preferred embodiments of the filter material, the process for manufacturing the filter material, the segment of the smoking article and the smoking article will be described below. Furthermore, Comparative Examples not according to the invention are described.

[0084] For the manufacture of the filter material, the arrangement shown in FIG. 1 was used.

[0085] A suspension 1 of pulp fibers and fibers from regenerated cellulose was provided in a storage tank 2, step A1, and from there pumped onto a running wire 3, inclined upwards with respect to the horizontal, step A2, and de-watered by vacuum boxes 9, step A3, so that a fiber web 4 was formed on the wire, the general direction of movement of which is indicated by the arrow 10. The fiber web 4 was removed from the wire 3 and transferred to a support wire 5 which was also running, step A4. There, water jets 11 arranged in several rows transverse to the running direction of the fiber web 4 were directed from devices 6 onto the fiber web 4 to entangle the fibers and to consolidate the fiber web 4 to a nonwoven, step B. In a further step, water jets 12 were also directed onto the other side of the fiber web 4 by additional devices 7, wherein the fiber web 4 was supported by a cylindrical reel 13, on the surface of which a plurality of prominences had been provided, step C. Next, the still-moist nonwoven ran through a drying device 8 and was dried there, step D, in order to obtain the filter material.

Exemplary Example 1

[0086] In order to manufacture the hydroentangled filter material, a mixture of pulp fibers from coniferous wood and Lyocell? fibers was used, wherein the amount of fibers was selected such that the finished filter material consisted of 65% pulp fibers and 35% Lyocell? fibers. The finished filter material had a basis weight of 55 g/m.sup.2 and a thickness of 330 ?m.

[0087] In step C of the manufacturing process, a row of water jets, 12 in FIG. 1, was directed onto the fiber web 4, while the fiber web 4 was supported by a reel, 13 in FIG. 1. The reel had prismatic prominences arranged next to each other (not shown in FIG. 1) with a square base of 1 mm?1 mm. The prominences were arranged in rows, wherein a distance of 1 mm was provided between neighboring rows and between the prominences in each row.

[0088] The prominences and the action of the water jets generated thin spots but also holes in the filter material, which provided the filter material with an overall irregular structure. The transparency of the filter material was measured on several randomly selected positions in accordance with DIN 53147:1993-01 and a value of 49.1% at a standard deviation of 0.76% (absolute) was obtained. FIG. 2 shows the filter material of Exemplary Example 1, designated by 1, wherein the line 4 is about 1 cm long.

Exemplary Example 2

[0089] In order to manufacture the hydroentangled filter material, a mixture of pulp fibers from coniferous wood and viscose fibers was used, wherein the amount of fibers was selected such that the finished filter material consisted of 80% pulp fibers and 20% viscose fibers. The finished filter material had a basis weight of 50 g/m.sup.2 and a thickness of 290 ?m.

[0090] In step C of the manufacturing process, a row of water jets, 12 in FIG. 1, was directed onto the fiber web 4, while the fiber web 4 was supported by a reel, 13 in FIG. 1. The reel, 13 in FIG. 1, was configured as in Exemplary Example 1, but the pressure of the water jets, 12 in FIG. 1, was selected to be higher.

[0091] The prominences and the action of the water jets generated thin spots, but because of the higher pressure, more holes were generated than in the filter material of Exemplary Example 1. The transparency of the filter material was measured on several randomly selected positions in accordance with DIN 53147:1993-01 and a value of 55.7% with a standard deviation of 1.62% (absolute) was obtained. FIG. 2 shows the filter material of Exemplary Example 2, designated by 2, wherein the line 4 is about 1 cm long.

Exemplary Example 3

[0092] In order to manufacture the hydroentangled filter material, the same mixture of fibers was used as in Exemplary Example 2. The finished filter material had a basis weight of 35 g/m.sup.2 and a thickness of 200 ?m.

[0093] Differing from the process according to the invention, step C was dispensed with and the pressure of the water jets in step B was selected to be so high that thin spots and holes in the filter material were generated in a very irregular arrangement.

[0094] The transparency of the filter material was measured on several randomly selected positions in accordance with DIN 53147:1993-01 and a value of 52.3% with a standard deviation of 2.47% (absolute) was obtained. FIG. 2. shows the filter material of Exemplary Example 3, designated by 3, wherein the line 4 is about 1 cm long.

Comparative Example A

[0095] In order to manufacture a filter material that was not according to the invention, the same mixture of fibers was used as in Exemplary Example 1. However, the basis weight was selected to be particularly low and was only 25.8 g/m.sup.2 in the finished filter material.

[0096] The filter material was manufactured according to steps A, B and D of the process according to the invention, but the generation of a structure in step C was dispensed with. The surface of the filter material was apparently much more homogeneous than that of Exemplary Examples 1 to 3.

[0097] The transparency of the filter material according to the invention was measured on several randomly selected positions in accordance with DIN 53147:1993-01 and a value of 38.2% with a standard deviation of 0.53% (absolute) was obtained. FIG. 2 shows the filter material of the Comparative Example that was not according to the invention, designated by A, wherein the line 4 is about 1 cm long.

[0098] Filter rods wrapped with paper were manufactured with a length of 100 mm and a diameter of 7.85 mm from each filter material of the Exemplary Examples 1 to 3 and of the Comparative Example. The width of the web of filter material and the machine settings during filter manufacture where selected such that for each filter rod, a similar draw resistance of 440?15 mmWG was obtained. Segments with a length of 20 mm were cut from the filter rod and American blend cigarettes with a length of 83 mm without filter ventilation were manufactured therefrom. The mean weight of the cigarettes was 932.7 mg. The cigarettes were smoked in accordance with the method specified in ISO 3308:2012 and the amount of nicotine-free dry particulate matter per cigarette was determined. The filter segments of the cigarettes were removed and the amount of nicotine-free dry particulate matter contained in each filter segment was also determined and the filtration efficiency in percent was calculated therefrom, wherein the filtration efficiency expresses which proportion of the nicotine-free dry particulate matter flowing into the filter segment is retained in the filter. Thus, in addition to the properties of the filter material, the filtration efficiency also depends on the length and the diameter of the filter segment.

[0099] The hardness of the filter rods was measured with a DD60A measuring instrument from Borgwaldt KC. Here, filter rods are exposed to a load by a test body with a defined force for a defined time and the deformation is measured and expressed as a percentage with respect to the undeformed state.

[0100] The draw resistance (PD) of the filter rod, the filtration efficiency (FE) for nicotine-free dry particulate matter and the hardness (HD) of the filter segment are shown in Table 1. In addition, the transparency (TR) of the filter material in accordance with DIN 53147:1993-01 is shown in Table 1. In addition to the Exemplary Examples 1-3 and the Comparative Example A, the data for a filter produced from cellulose acetate is shown as Comparative Example B. For the Comparative Example B, no transparency could be measured as the filter material was not in the form of a fiber web.

TABLE-US-00001 TABLE 1 TR PD FE HD Example % mmWG % % 1 49.1 443 67.3 78 2 55.7 445 65.0 80 3 52.3 429 62.8 77 A 38.2 438 75.3 81 B 440 54.1 84

[0101] It can be seen from Table 1 that at a comparable draw resistance, the filtration efficiency of the segments from Exemplary Examples 1 to 3 is significantly closer to the filtration efficiency of a filter from cellulose acetate, Comparative Example B, than the segment of Comparative Example A, not according to the invention. Apparently, despite the similar draw resistance, the network-like structure of Exemplary Examples 1 to 3 allows for a better flow of the aerosol through the segment, so that less nicotine-free dry particulate matter is filtered out of the aerosol. It can also be seen that this reduction of the filtration efficiency is accompanied by an increase in transparency, so that the transparency is in fact a suitable parameter for characterizing the irregularities of the filter material and to establish a connection with the filtration efficiency.

[0102] The hardness of the segments from the Exemplary Examples 1 to 3 according to the invention is slightly lower than that of the Comparative Examples A and B. This is of lesser importance because such a small difference in hardness can also be compensated for by selecting a stiffer wrapping material for the segment.

[0103] A subjective comparison of the optical appearance of the filter cross-section of the cigarettes visible at the mouth end from Exemplary Examples 1 to 3 with the filter produced from cellulose acetate, Comparative Example B, shows that they differ only slightly and in this respect are in any case significantly more similar to Comparative Example B than conventional paper filters.

[0104] Thus, it has been shown that segments can be manufactured from the filter material according to the invention, the properties of which with respect to draw resistance, filtration efficiency, hardness and optical appearance, are overall closer to filters produced from cellulose acetate than filter materials produced from paper or hydroentangled filter materials not according to the invention. The biodegradability of the filter materials according to the invention is, however, significantly better than those produced from cellulose acetate.

[0105] An oral nicotine delivery product in the form of a pouch filled with prepared tobacco was manufactured from the filter material according to the invention of Exemplary Example 2, wherein with respect to the use, no differences with respect to conventional oral nicotine delivery products were found. The pouch, however, has better biodegradability than conventional pouches.