Structured filter materials for nicotine delivery products

Abstract

1. A filter material for producing a nicotine delivery product, comprising: a filter material comprising: a first filter layer; a second filter layer; and a third filter layer having a thickness of at least 25 g / m. The filter material comprises at least 50% by weight and at most 100% by weight of cellulose fibers, based on the weight of the filter material. 2 And a maximum of 60g / m 2 and the filter material has a structure characterized in that it provides the filter material with a transparency of at least 45% and at most 70% as measured according to DIN 53147:1993-01.Further described are segments comprising the filter material for nicotine delivery products, smoking devices comprising such segments, oral nicotine delivery products, and methods of making the filter material.

Description

[Technical Field]

[0001] The present invention relates to a filter material for a nicotine delivery product, a segment for a smoking device made therefrom, or an oral nicotine delivery product made therefrom, said filter material having a structure that provides advantageous properties to the nicotine delivery product, for example, with respect to hardness, resistance to draw, filtration efficiency, optical appearance, or biodegradability. The structure of the filter material is thereby characterized by its transparency. [Background technology]

[0002] The nicotine delivery product can be a smoking device. A smoking device is typically a rod-shaped article consisting of at least two rod-shaped segments arranged side by side. A segment comprises a material capable of generating an aerosol when heated, and at least one further segment comprises a material that functions to affect the aerosol properties.

[0003] The smoking device may be a filter cigarette, comprising a first segment made of an aerosol-forming material, in particular tobacco, and a further segment formed as a filter and serving to filter the aerosol, wherein the aerosol is generated by burning the aerosol-forming material, and the filter serves to filter the aerosol and provide a defined resistance to draw for the filter cigarette.

[0004] The smoking device may also be a so-called heated tobacco product, in which the aerosol-generating material is heated but not burned, thereby reducing the number and amount of harmful substances in the aerosol. Such smoking devices also consist of at least two segments, but often more, particularly four segments. The segments contain the aerosol-generating material, which typically comprises tobacco, reconstituted tobacco, tobacco treated in other ways or with nicotine and glycerol or propylene glycol. Furthermore, in some cases, the optical segments of the heated tobacco product function to transport, cool, or filter the aerosol.

[0005] The segments are usually wrapped in a packaging material, very frequently paper being used as the packaging material.

[0006] Hereinafter, unless expressly indicated otherwise or directly derived from the context, the term "segment" should be understood to mean a segment of a smoking device that does not include aerosol-generating materials, but that serves, for example, to transport, cool or filter the aerosol.

[0007] In the prior art, it is known to form such segments from cellulose acetate or polylactic acid. Because cellulose acetate and polylactic acid biodegrade very slowly in the environment, the industry is interested in manufacturing smoking article segments from other materials that biodegrade better. In the prior art, it is known to manufacture segments for smoking articles, particularly filter segments, from paper. While such segments generally biodegrade well, they suffer from several drawbacks. For example, filter segments made from paper generally have high filtration efficiency and therefore produce a dry aerosol, which impairs the taste of the aerosol compared to cigarettes equipped with conventional filter segments made from cellulose acetate. Furthermore, filter segments made from paper often have lower filtration efficiency for phenols than cellulose acetate. In addition, it has proven difficult to manufacture paper segments that are acceptable to consumers in terms of a combination of resistance to draw, filtration efficiency, and hardness. To reduce filtration efficiency, less paper is often used, resulting in a softer segment and a lower resistance to draw.

[0008] However, another reason why paper filter segments have not yet found widespread use is their optical appearance. At the mouth end of a smoking device, the cut surface of the mouth-end-located segment is often visible, whereas with conventional segments made from cellulose acetate, consumers are accustomed to a homogeneous white surface in which individual cut fibers are barely discernible. However, paper segments have a rough structure that conveys a distinctly lower quality impression to consumers. Therefore, paper segments are often used only as one segment in a filter consisting of several segments, so that the cut surface is not visible to consumers. Therefore, mouth-end-located segments are still frequently made from cellulose acetate. Due to these optical disadvantages, the biodegradability advantages of paper segments cannot be fully utilized.

[0009] The nicotine delivery product may be an oral nicotine delivery product. Oral nicotine delivery products are usually small pouches made of nonwoven fabric containing nicotine-containing materials, such as tobacco. During use, consumers hold the pouch in their mouths for a while, allowing substances, particularly nicotine, to be released from the nicotine-containing materials. However, nonwoven fabric-formed pouches contain plastic and are therefore not biodegradable. Examples of oral nicotine delivery products are pouch-filled products such as Swedish snus, white snus, or other smokeless tobacco products. Non-tobacco-containing oral nicotine delivery products are also known.

[0010] It would therefore be of interest to the industry to have available filter materials that allow for the manufacture of segments for smoking articles having an advantageous combination of filtration efficiency, resistance to draw, hardness and optical appearance, or that allow for the manufacture of nicotine delivery products with excellent biodegradability. Summary of the Invention

[0011] The object of the present invention is to provide a filter material for smoking articles which is as similar as possible to conventional segments made from cellulose acetate in terms of hardness, resistance to draw, filtration efficiency and optical appearance, and which further makes it possible to produce segments which are fully biodegradable.

[0012] It is a further object of the present invention to provide a filter material from which oral nicotine delivery products can be manufactured, which filter material has excellent biodegradability.

[0013] These objects are achieved by a filter material according to claim 1, a method for producing a filter material according to claim 27, a segment of a smoking article according to claim 15, a smoking article according to claim 21 and an oral nicotine delivery product according to claim 26. Advantageous embodiments are defined in the independent claims.

[0014] The inventors have discovered that these objects are achieved by a filter material, said filter material being hydroentangled and comprising at least 50% and at most 100% by weight of cellulose fibers, each based on the weight of the filter material, said filter material having a density of at least 25 g / m 2 And a maximum of 60g / m 2 and wherein the filter material has a structure that provides the filter material with a transparency of at least 45% and at most 70%, as measured in accordance with DIN 53147:1993-01.

[0015] According to the present invention, the filter material is produced by hydroentanglement. This production method differentiates it from other filter materials, particularly paper, and provides it with distinctive properties that cannot be similarly obtained by other production methods. In contrast to paper, for example, where strength is primarily due to hydrogen bonding and fibers are primarily oriented in the plane of the paper, the strength of hydroentangled nonwoven fabrics is achieved through fiber entanglement, thus further orienting a significant proportion of the fibers through the thickness of the nonwoven fabric. This fiber orientation is essential for the segments produced therefrom to have advantageous properties, particularly with regard to resistance to draw, filtration efficiency, and hardness.

[0016] The inventors have found that segments made from hydroentangled filter materials according to the present invention generally have superior properties to segments made from paper, but there is still room for further optimization of these properties, bringing them even closer to those of cellulose acetate segments. Similar to segments made from paper, but to a lesser extent, excellent filtration efficiency can lead to problems, such as using too little filter material, and therefore, the resistance to draw, particularly the hardness of the segments, cannot fully satisfy consumer expectations. According to the inventors' findings, the special structure of the filter material can solve this problem. The inventors have recognized that it is advantageous for the filter material not to have a substantially uniform surface like a paper sheet or plastic film, but rather to have multiple variations in thickness or basis weight distributed across its entire surface. These variations can be, for example, regularly or irregularly arranged holes or thin spots on the filter material. In this regard, the inventors have found that it is advantageous if the holes or thin spots are not produced by the removal of material, but rather by a redistribution and modification of the arrangement of the fibers in the filter material, in whole or in part, which can be achieved by the manufacturing method according to the invention as explained below.

[0017] In this regard, the exact shape and arrangement of the variations is not important, but they must be more or less uniformly distributed over the entire surface and exceed a certain magnitude. To characterize these variations, and in particular their magnitude, the inventors considered various parameters such as thickness, basis weight or air permeability. However, it turned out that these parameters could not be measured with a sufficiently low spatial resolution to obtain said variations.

[0018] However, the inventors have realized that the transparency of the filter material changes due to the redistribution of fibers. In other words, the special structure that distinguishes the filter material according to the present invention provides the filter material with a characteristically higher permeability, which differentiates the filter material from filter materials of the same basis weight and similar composition but with conventional structure. In this regard, permeability is a suitable, clearly measurable parameter that can be used to characterize the desired structure of the filter material.

[0019] The observed increase in permeability of the filter material having the desired structure is surprising in this respect, since one would expect that the redistribution of fibers would indeed make the holes or thin spots more permeable, but then the areas between the holes and thin spots, where there are more fibers, would become less permeable, so that on average there would be little or no effect on clarity overall. However, experiments have shown that, in fact, the lowest basis weight of 25 g / m 2 according to the present invention 2 Even at this temperature, filter materials with conventional structures have a transparency according to DIN 53147:1993-01 that does not exceed a value of 40%. Higher transparency can only be obtained by a redistribution of the fibers, which is directly related to the holes and thin spots resulting from the redistribution of the fibers in the structure of the filter material; this also leads to the advantages according to the invention regarding the hardness and suction resistance of the segments produced therefrom.

[0020] The inventors have found that cellulose fibers are necessary to provide a filter material with sufficient strength so that it can be processed into segments. According to the invention, the proportion of cellulose fibers in the filter material is at least 50% and at most 100% by weight, preferably at least 60% and at most 100% by weight, particularly preferably at least 70% and at most 95% by weight, based on the weight of the filter material.

[0021] The cellulose fibers may be pulp fibers or fibers from regenerated cellulose or a mixture thereof.

[0022] The pulp fibers are preferably sourced from coniferous wood, deciduous wood, or other plants such as hemp, flax, jute, ramie, kenaf, kapok, coconut, abaca, sisal, bamboo, cotton, or Esperanto grass. In addition, a mixture of pulp fibers from various sources can be used to manufacture the hydroentangled filter material. Particularly preferably, the pulp fibers are sourced from coniferous wood, since even a smaller proportion of such fibers provides a filter material with excellent strength.

[0023] The filter material according to the invention may comprise fibers from regenerated cellulose, preferably the proportion of fibers from regenerated cellulose is at least 5% and at most 50% by weight, particularly preferably at least 10% and at most 45% by weight, in particular at least 15% and at most 40% by weight, based on the weight of the filter material.

[0024] The fibers from regenerated cellulose are preferably viscose fibers, modal fibers, Lyocell®, Tencel®, or combinations thereof. These fibers have excellent biodegradability and can be used to optimize the strength of the filter material and tailor the filtration efficiency of the segments made therefrom to the smoking device. Due to their manufacturing method, these fibers are less variable than pulp fibers from natural sources, thus contributing to lower variability in the properties of the segments made from the filter material than if pulp fibers were used exclusively.

[0025] According to the invention, the basis weight of the filter material is at least 25 g / m 2 And a maximum of 60g / m 2 , preferably at least 28 g / m 2 And a maximum of 55g / m 2 , particularly preferably at least 30 g / m 2 And a maximum of 55g / m 2 The basis weight affects the tensile strength of the filter material, with higher basis weights resulting in higher strength. The values ​​refer to basis weights measured according to ISO 536:2012.

[0026] According to the present invention, the transparency of the filter material, as measured according to DIN 53147:1993-01, is at least 45% and at most 70%, preferably at least 50% and at most 66%. A transparency exceeding at least 45% due to the redistribution of fibers has a positive effect on the hardness and suction resistance of the segments made from the filter material. However, the transparency should not be too high, since then thin spots and holes will prevail to the extent that the strength of the filter material is no longer suitable for making segments from it.

[0027] In fact, the shape and size of the variations cannot be precisely defined, since they cannot be precisely separated from the surrounding filter material; however, obviously, each individual variation must be much smaller than the area of ​​the filter material required for the production of the segment. Since the special structure of the filter material is also formed by the holes, the majority of the holes, for example, more than 90% of the holes, have an area of ​​preferably 10 mm 2 On these scales, the measurement area for the measurement of transparency according to DIN 53147:1993-01 is approximately 2.5 cm 2 and therefore, transparency is particularly suitable as a parameter for characterizing the structure of a filter material, since, taken together, it typically includes holes or thin spots as well as surrounding areas. An embodiment illustrating these variations is shown by way of example in FIG. 2 and described below. However, the present invention is not limited to the feature size variations shown in FIG. 2.

[0028] To adjust specific properties, the filter material according to the invention can contain additives such as alkylketene dimers (AKD), alkenylsuccinic anhydrides (ASA), fatty acids, starches, starch derivatives, carboxymethylcellulose, alginates, wet strength additives or substances for adjusting the pH, such as, for example, organic or inorganic acids or bases. As additives, the filter material according to the invention can also contain one or more burn additives selected from the group consisting of citrates, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, alpha-hydroxycaprylates, phosphates, polyphosphates, hydrochlorides and bicarbonates, and mixtures thereof, particularly preferably trisodium citrate, tripotassium citrate and combinations thereof.

[0029] Those skilled in the art will be able to empirically determine the types and amounts of such additives.

[0030] The filter material according to the present invention may also contain other substances that allow the filtration efficiency of the filter material to better match that of cellulose acetate. In a preferred embodiment of the filter material according to the present invention, the filter material comprises a substance selected from the group consisting of triacetin, propylene glycol, sorbitol, glycerol, polyethylene glycol, polypropylene glycol, polyvinyl alcohol and triethyl citrate, or a mixture thereof.

[0031] The thickness of the filter material, as measured in accordance with ISO 534:2011, is at least 70 μm and at most 1000 μm, preferably at least 100 μm and at most 800 μm, and particularly preferably at least 150 μm and at most 750 μm. This thickness influences the amount of filter material that can be packed into a segment of a smoking article, and thus the segment's resistance to draw and filtration efficiency, as well as the processability of the filter material, which is often crimped or folded to produce segments for the smoking article. Because of these process steps, a too large thickness would be disadvantageous, and the preferred and particularly preferred spacing thicknesses allow for particularly good processability of the filter material according to the present invention to form segments of a smoking article.

[0032] The mechanical properties of the filter material are important for processing the filter material according to the present invention into a nicotine delivery product. In particular, holes or thin spots should not excessively reduce the strength of the filter material. When measured according to ISO 1924-2:2008, the tensile strength across the width of the filter material is preferably at least 0.05 kN / m and at most 5 kN / m, particularly preferably at least 0.07 kN / m and at most 4 kN / m.

[0033] The elongation at break of the filter material is important because during processing of the filter material according to the invention into a nicotine delivery product, the filter material is often stretched or stressed in the direction of travel, and therefore a particularly high elongation at break is advantageous. Thus, when measured according to ISO 1924-2:2008, the elongation at break of the filter material is preferably at least 1% and at most 50%, particularly preferably at least 3% and at most 40%.

[0034] The tensile strength and elongation at break may depend on the direction in which the sample for measurement is taken from the filter material, and the characteristics of the filter material depend on whether the tensile strength or elongation at break, respectively, in at least one direction is in a preferred or particularly preferred interval.

[0035] Segments for smoking articles can be produced from the filter material of the present invention using methods known in the art. These methods include, for example, crimping or folding the filter material, forming a continuous rod from the crimped or folded filter material, wrapping the continuous rod with a wrapping material, and cutting the wrapped rod into individual rods of a specified length. In many cases, the length of such rods will be an integral multiple of the length of the segments to be used in the smoking article according to the present invention, and therefore the rods are then cut into segments of the desired length before or during the manufacture of the smoking article.

[0036] A segment according to the invention for a smoking article comprises a filter material according to the invention and a wrapping material.

[0037] In a preferred embodiment of the segments according to the invention, the segments are cylindrical with a diameter of at least 3 mm and at most 10 mm, particularly preferably at least 4 mm and at most 9 mm, more particularly preferably at least 5 mm and at most 8 mm. These diameters are advantageous for the use of the segments according to the invention in smoking articles.

[0038] In a preferred embodiment of the segment according to the invention, the segment has a length of at least 4 mm and at most 40 mm, particularly preferably at least 6 mm and at most 35 mm, in particular at least 10 mm and at most 28 mm.

[0039] The resistance to draw of a segment determines, among other things, how much pressure difference a smoker must apply during consumption of the smoking device in order to draw a specific volumetric flow rate through the smoking device, and therefore, the resistance to draw of the segment essentially influences the smoker's acceptance of the smoking device. The resistance to draw of a segment can be measured in accordance with ISO 6565:2015 and is expressed in mm water gauge (mmWG). To a very good approximation, the resistance to draw of a segment is proportional to the length of the segment, so that for rods different from the segment, measurements of the resistance to draw can be made only at the length of the rod. The resistance to draw of a segment can be easily calculated from this.

[0040] The resistance to attraction of the segment per unit length of the segment is preferably at least 1 mmWG / mm and at most 12 mmWG / mm, particularly preferably at least 2 mmWG / mm and at most 10 mmWG / mm.

[0041] The packaging material for the segments according to the invention is preferably paper or film.

[0042] The packaging material for the segments according to the invention preferably has a mass of at least 20 g / m 2 And a maximum of 150 g / m 2 , particularly preferably at least 30 g / m 2 And a maximum of 130g / m 2 Packaging materials having this preferred or particularly preferred basis weight provide the segments according to the invention packaged therewith with a particularly advantageous hardness, which means that a smoker cannot accidentally pressurize the segments placed inside a smoking article.

[0043] Smoking articles according to the present invention can be manufactured from segments according to the present invention using methods known in the art.

[0044] A smoking device according to the present invention comprises a segment containing an aerosol-forming material and a segment comprising a filter material and a wrapping material according to the present invention.

[0045] In a preferred embodiment, the segment of the smoking article adjacent the mouth end is a segment according to the present invention, since the cross section of the segment according to the present invention is optically similar to the cross section of a cellulose acetate segment.

[0046] In a preferred embodiment, the smoking device is a filter cigarette and the aerosol-forming material comprises tobacco.

[0047] In a preferred embodiment, the smoking device is one in which, during intended use, the aerosol-forming material is only heated and does not burn, and the aerosol-forming material comprises tobacco, reconstituted tobacco, nicotine, glycerol, propylene glycol, or mixtures thereof.

[0048] The transparency of the filter material due to its special structure offers further advantages. Some smoking devices are designed to allow smokers to see inside the device. For such devices, the packaging material is partially transparent or provides holes that allow direct viewing of the filter material. However, due to these low transparencies, filters known in the art cannot be seen. When the filter material of the present invention has a transparency of more than 50%, it is possible to recognize, for example, a frangible capsule filled with flavoring placed in the filter. Thus, in a particularly preferred embodiment of the smoking device, the smoking device comprises a segment containing an aerosol-forming material and a segment comprising the filter material of the present invention and a packaging material, the packaging material being at least partially transparent or having holes, and the filter material having a transparency of at least 50% as measured in accordance with DIN 53147:1993-01.

[0049] The inventors have surprisingly found that the filter material is also suitable for oral nicotine delivery products. The inventors have found that the filter material according to the invention has excellent biodegradability due to its special structure characterized by its composition and transparency, and that the filter material according to the invention has excellent permeability to substances released from the nicotine-containing material of the oral nicotine delivery product during use, making it particularly suitable for nicotine delivery products.

[0050] Thus, an oral nicotine delivery product according to the invention comprises a pouch formed with a filter material according to the invention and containing a nicotine-containing material, preferably said filter material having a transparency of at least 50% and at most 70% as measured according to DIN 53147:1993-01.

[0051] The nicotine-containing material may preferably be tobacco.

[0052] The filter material according to the present invention can be produced according to the following method according to the present invention, which comprises steps A to D: A - providing a fibrous web comprising cellulose fibers; B - hydroentangling a fibrous web with at least one water jet directed at said fibrous web to produce a hydroentangled fibrous web; C--creating a structure within said hydroentangled fibrous web; D- drying the hydroentangled fibrous web; the amount of cellulose fibers in step A is selected so that after drying in step D the filter material contains at least 50% by weight and at most 100% by weight of cellulose fibers relative to the weight of the filter material, After drying in step D, the filter material has a density of at least 25 g / m 2 And a maximum of 60g / m 2 and After drying in step D, the filter material has a structure characterized by providing the filter material with a transparency of at least 45% and at most 70%, as measured according to DIN 53147:1993-01; The creation of the structure in step C is carried out by directing at least one water jet at the fibrous web, the fibrous web being supported by a surface having a plurality of protrusions.

[0053] At least one water jet directed at the fibrous web in step C causes the fibers to be arranged around the protrusions, causing a redistribution of the fibers to be replaced by the protrusions. The protrusions thus create holes or thin spots, depending on the pressure of the water jet and the amount of fibers initially present in the area of ​​the protrusions. This structure provides the filter material with the characteristically increased transparency described earlier. However, the shape of the protrusions generally shifts imprecisely to the fibrous web, so that the holes or thin spots in the fibrous web and the filter material vary in shape and size, even when all protrusions have the same shape. However, an increase in transparency can be reliably demonstrated. Thinner spots, and especially holes, can also be produced, essentially by embossing or punching, but in this case the fibers are not pressed or cut and arranged differently. However, by the method according to the present invention described herein, the fibers are arranged around the holes or thin spots, thus obtaining a network-like structure. This network-like structure allows segments made therefrom to be stiffer and have a lower resistance to draw for a given material than filter materials having a generally uniform surface or that are made by embossing or punching.

[0054] The filter material produced by this method should be suitable for use in a nicotine delivery product, in particular said filter material may have all the features, individually or in combination, described above in connection with said filter material and set out in the claims directed to said filter material.

[0055] In a preferred embodiment of the method according to the invention, providing a fibrous web in step A comprises spinning a plurality of cellulose fibers, said cellulose fibers being formed by filaments of regenerated cellulose, and after drying in step D, at least 90% of the mass of the filter material is formed by filaments of regenerated cellulose. In a particularly preferred embodiment of this method, the filaments of regenerated cellulose are Lyocell®.

[0056] In another preferred embodiment of the method according to the present invention, providing the 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 A to the running wire; A3 - dewatering said suspension by said traveling wire to form a fibrous web; A4 - transferring the fibrous web from step A3 onto a support wire; Includes:

[0057] In a preferred embodiment of the process according to the invention, the aqueous suspension in step A1 has a solids content of at most 3.0%, particularly preferably at most 1.0%, more particularly preferably at most 0.2%, in particular at most 0.05%. A particularly low solids content of the suspension allows a low-density fiber web to be formed in step A3, which is advantageous in terms of the filtration efficiency of the segments produced therefrom.

[0058] In a preferred embodiment of the method according to the invention, the running wire in steps A2 and A3 is inclined above the running direction of the fiber web at an angle of at least 3° and at most 40° to the horizontal, particularly preferably at an angle of at least 5° and at most 30°, more particularly preferably at an angle of at least 15° and at most 25°.

[0059] In a preferred embodiment, the method comprises a step in which a pressure difference is created between the two sides of the running wire to support the dewatering of the suspension in step A3, particularly preferably said pressure difference is created by a vacuum box or by suitably shaped fins.

[0060] In a preferred embodiment of the method according to the invention, a plurality of water jets are used for hydroentangling in step B, said water jets being arranged in at least one row transverse to the running direction of the fibrous web.

[0061] In a preferred embodiment of the method according to the invention, the hydroentangling in step B is carried out by means of at least two water jets directed at the fibrous web, particularly preferably the at least two water jets acting on different sides of the fibrous web.

[0062] In a preferred embodiment of the method according to the invention, the fibrous web in step C is supported by a cylinder, on the surface of which a plurality of protrusions are arranged.

[0063] Preferably, in step C, the area of ​​each protrusion protruding above the surface supporting the fiber web is at least 0.1 mm 2 And a maximum of 15 mm 2 , particularly preferably at least 0.25 mm 2 And a maximum of 10 mm 2 is.

[0064] In a preferred embodiment of the method according to the invention, the method comprises the further step of applying one or more additives to the fibrous web, preferably selected from the group consisting of alkyl ketene dimers (AKD), alkenyl succinic anhydrides (ASA), fatty acids, starch, starch derivatives, carboxymethylcellulose, alginates, wet strength agents, substances for adjusting the pH, such as organic or inorganic acids or bases, and mixtures thereof, or the additive is a burn additive selected from the group consisting of citrates, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, alpha-hydroxycaprylates, phosphates, polyphosphates, hydrochlorides and bicarbonates, and mixtures thereof.

[0065] In a preferred embodiment of the process according to the invention, the application of the additive or additives is carried out between step C and step D of the process according to the invention. In another preferred embodiment of the process according to the invention, the application of the additive or additives is carried out after step D, followed by drying of the fibrous web in a further step.

[0066] In a preferred embodiment of the method according to the invention, drying in step D is carried out at least in part by contact with hot air, infrared radiation or microwave radiation. Drying by direct contact with a heated surface is also possible, but is less preferred as this may result in a reduction in the thickness of the hydroentangled filter material.

[0067] In a further method, a filter material according to the invention can also be produced by steps A, B, and D, where step C is omitted, and thus the method is not according to the invention. In step B, a high pressure is selected for some of the water jets, so that the water jets create holes or thin spots in the fiber web supported by the support wires. For filter materials produced by this method, the variations may be much less widespread spatially, and therefore the filter material is only according to the invention if the machine settings, e.g., the water jet pressure, are selected so that the transparency of the filter material is at least 45% and at most 70%. [Brief explanation of the drawings]

[0068] [Figure 1] FIG. 1 shows an arrangement by means of which the method according to the invention for the production of hydroentangled filter material can be carried out. [Figure 2] FIG. 2 shows, by way of example, a filter material according to the invention and a filter material not according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0069] Some preferred embodiments of the filter material, the method of manufacturing the filter material, the segment of the smoking article, and the smoking article are described below. In addition, comparative examples not according to the present invention are also described.

[0070] For the production of the filter material, the arrangement shown in Figure 1 was used.

[0071] A fiber suspension 1 made of pulp fibers and regenerated cellulose is prepared in a storage tank 2, from which it is pumped onto a traveling wire 3 inclined upward relative to the horizontal, step A1, where it is dewatered by a vacuum box 9, step A2, resulting in the formation of a fiber web 4 on the wire, the general direction of which is indicated by arrow 10, step A3. The fiber web 4 is then removed from the wire 3 and transferred to a supporting wire 5, which is also traveling, step A4. Here, water jets 11, arranged in several rows transverse to the traveling direction of the fiber web 4, are directed from a device 6 onto the fiber web 4, intertwining the fibers and fixing the fiber web 4 to a nonwoven fabric, step B. In a further step, water jets 12 are also directed by an additional device 7 onto the other side of the fiber web 4, where the fiber web 4 is supported by a cylindrical reel 13, on the surface of which a number of protrusions are provided, step C. The still wet nonwoven fabric then passes through a drying device 8 where it is dried to obtain a filter material, step D.

[0072] Illustrative Example 1 To produce the hydroentangled filter material, a mixture of pulp fibres from softwood and Lyocell® was used, the amount of fibres being chosen so that the final filter material consisted of 65% pulp fibres and 35% Lyocell® fibres. The final filter material had a density of 55 g / m 2 and a thickness of 330 μm.

[0073] In step C of the manufacturing process, an array of water jets, 12 in Figure 1, was directed at the fibrous web 4, which was supported by a reel, 13 in Figure 1, which had side-by-side prismatic protrusions (not shown in Figure 1) with square bases measuring 1 mm x 1 mm. The protrusions were arranged in rows with a distance of 1 mm between adjacent rows and between the protrusions in each row.

[0074] The action of the protrusions and water jets created thin spots and holes in the filter material, which provided the filter material with an overall irregular structure. The transparency of the filter material was measured at several randomly selected locations according to DIN 53147:1993-01, yielding a value of 49.1% with a standard deviation (absolute) of 0.76%. Figure 2 shows the filter material of exemplary example 1, designated 1, where line 4 is approximately 1 cm long.

[0075] Illustrative Example 2 To produce the hydroentangled filter material, a mixture of pulp and viscose fibers from softwood was used, the amount of fibers being selected such that the final filter material consisted of 80% pulp fibers and 20% viscose fibers. The final filter material had a density of 50 g / m 2 and a thickness of 290 μm.

[0076] In step C of the manufacturing method, an array of water jets, 12 in FIG. 1, was directed at the fibrous web 4, which 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 chosen to be higher.

[0077] The action of the protrusions and water jets produced thin spots, but the high pressure produced more holes than the filter material of Illustrative Example 1. The transparency of the filter material was measured at several randomly selected locations according to DIN 53147:1993-01, yielding a value of 55.7% with a standard deviation (absolute) of 1.62%. Figure 2 shows the filter material of Illustrative Example 2, designated 2, where line 4 is approximately 1 cm long.

[0078] Illustrative Example 3 The same fiber mix was used to make the hydroentangled filter material as in Illustrative Example 2. The final filter material had a fiber count of 35 g / m 2 and a thickness of 200 μm.

[0079] Unlike the method according to the invention, step C was omitted and the water jet pressure in step B was chosen to be very high, resulting in very irregularly distributed thin spots and holes in the filter material.

[0080] The transparency of the filter material was measured at several randomly selected positions according to DIN 53147:1993-01, yielding a value of 52.3% with a standard deviation (absolute) of 2.47%. Figure 2 shows the filter material of exemplary example 3, designated 3, where line 4 is approximately 1 cm long.

[0081] Comparative example A To produce a filter material not according to the invention, the same fiber mixture as in Illustrative Example 1 was used. However, the basis weight was chosen to be particularly low, being only 25.8 g / m in the final filter material. 2 It was.

[0082] A filter material was produced according to steps A, B and D of the method according to the invention, but omitting the creation of the structure in step C. The surface of the filter material was clearly much more uniform than in illustrative examples 1-3.

[0083] The transparency of the filter material according to the invention was measured at several randomly selected positions according to DIN 53147:1993-01, giving a value of 38.2% with a standard deviation (absolute) of 0.53%. Figure 2 shows a comparative filter material not according to the invention, assigned A, line 4, which is approximately 1 cm long.

[0084] Paper-wrapped filter rods with a length of 100 mm and a diameter of 7.85 mm were produced from each filter material of Illustrative Examples 1-3 and the Comparative Example. The web width of the filter material and the machine settings during filter production were selected to obtain a similar resistance to draw of 440±15 mmWG for each filter rod. Segments with a length of 20 mm were cut from the filter rods, and 83 mm long American blend cigarettes without filter ventilation were produced from them. The average weight of the cigarettes was 932.7 mg. The cigarettes were smoked according to 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. The filtration efficiency percentage was calculated from this, and the filtration efficiency represents the percentage of nicotine-free dry particulate matter that entered the filter segment and remained in the filter. Therefore, in addition to the properties of the filter material, filtration efficiency also depends on the length and diameter of the filter segment.

[0085] The stiffness of the filter rods was measured using a Borgwaldt KC DD60A measuring device, in which the filter rods were subjected to a load by a test specimen at a specified force for a specified time, and the deformation was measured and expressed as a percentage of the undeformed state.

[0086] The resistance to draw (PD) of the filter rod, the filtration efficiency (FE) for nicotine-free dry particulate matter, and the hardness (HD) of the filter segments are shown in Table 1. Additionally, the transparency (TR) of the filter material according to DIN 53147:1993-01 is shown in Table 1. In addition to illustrative Examples 1-3 and Comparative Example A, data for a filter made from cellulose acetate is shown as Comparative Example B. For Comparative Example B, the transparency could not be measured because the filter material was not in the form of a fibrous web.

[0087] [Table 1]

[0088] It can be seen from Table 1 that, at comparable resistances to draw, the filtration efficiencies of the segments of Illustrative Examples 1-3 are significantly closer to that of the cellulose acetate filter, Comparative Example B, than the segment of Comparative Example A, not according to the invention. Clearly, despite similar resistances to draw, the network-like structure of Illustrative Examples 1-3 allows for better flow of the aerosol through the segments, resulting in less nicotine-free dry particulate matter being filtered out of the aerosol. This decrease in filtration efficiency is accompanied by an increase in transparency, and it can be seen that transparency is, in fact, a suitable parameter for characterizing the disorder of the filter material and relating it to filtration efficiency.

[0089] The hardness of the segments from illustrative examples 1 to 3 according to the invention is slightly lower than the hardness of the segments from comparative examples A and B. This is not very important, as such small differences in hardness can also be compensated for by choosing a harder packaging material for the segments.

[0090] A subjective comparison of the optical appearance of the filter cross-sections visible at the mouth end of cigarettes from Illustrative Examples 1-3 with a filter made from cellulose acetate, Comparative Example B, shows that they differ only slightly and, in any event, are significantly more similar to Comparative Example B than to conventional paper filters.

[0091] Thus, segments can be made from filter materials according to the invention, and the properties of said segments in terms of resistance to draw, filtration efficiency, hardness and optical appearance have been found to be generally closer to filters made from cellulose acetate than to filter materials made from paper or hydroentangled filter materials not according to the invention. However, the biodegradability of filter materials according to the invention is significantly better than that of filter materials made from cellulose acetate.

[0092] Oral nicotine delivery products in the form of pouches filled with prepared tobacco were produced from the filter material according to the present invention of Illustrative Example 2, and no difference in use was observed compared to conventional oral nicotine delivery products. However, the pouches have better biodegradability than conventional pouches.

Claims

1. 1. A filter material for producing a nicotine delivery product, comprising: the filter material is hydroentangled and comprises at least 50% and at most 100% by weight of cellulose fibers, each based on the weight of the filter material; The filter material has a density of at least 25 g / m ２ And at most 60 g / m ２ and 1. A filter material having a structure characterized in that it provides the filter material with a transparency of at least 45% and at most 70% as measured in accordance with DIN 53147:1993-01.

2. 2. The filter material according to claim 1, wherein the proportion of cellulose fibers in the filter material is at least 60% by weight and at most 100% by weight, preferably at least 70% by weight and at most 95% by weight, each relative to the weight of the filter material.

3. 3. The filter material according to claim 1, wherein the cellulose fibers are formed from pulp fibers, fibers from regenerated cellulose, or a mixture thereof.

4. The cellulose fibers are formed from pulp fibers or a mixture of pulp fibers, 4. The filter material of claim 3, wherein the pulp fibers are sourced from softwood, deciduous wood, hemp, flax, jute, rhubarb, kenaf, kapok, coconut, abaca, sisal, bamboo, cotton, or espalier, or are formed by a mixture of pulp fibers from two or more of these sources.

5. 5. The filter material according to claim 3, wherein the proportion of fibers from regenerated cellulose is at least 5% by weight and at most 50% by weight, preferably at least 10% by weight and at most 45% by weight, particularly preferably at least 15% by weight and at most 40% by weight, based on the weight of the filter material.

6. The cellulose fibers are formed from fibers derived from regenerated cellulose, 6. The filter material according to any one of claims 3 to 5, wherein the fibres from regenerated cellulose are viscose fibres, modal fibres, Lyocell®, Tencel® or mixtures thereof.

7. The basis weight of the filter material is at least 28 g / m according to ISO 536:2012 ２ And at most 55 g / m ２ , preferably at least 30 g / m ２ And at most 55 g / m ２ The filter material according to any one of claims 1 to 6, wherein

8. The filter material according to any one of claims 1 to 7, wherein the transparency of the filter material is at least 50% and at most 66% when measured according to DIN 53147:1993-01.

9. the structure includes a plurality of holes in the filter material; At least 90% of the plurality of holes are 10 mm ２ 9. The filter material of claim 1, having an area of ​​less than 1 / 2 mm.

10. 10. The filter material of any one of claims 1 to 9, further comprising one or more additional components selected from the group consisting of alkyl ketene dimers (AKD), alkenyl succinic anhydrides (ASA), fatty acids, starches, starch derivatives, carboxymethyl cellulose, alginates, wet strength agents, substances for adjusting pH, and burn additives selected from the group consisting of citrates, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxalates, salicylates, alpha-hydroxycaprylates, phosphates, polyphosphates, hydrochlorides, and bicarbonates, and mixtures thereof.

11. 11. The filter material of claim 1, further comprising 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. 12. The filter material according to claim 1, wherein the thickness of the filter material is at least 70 μm and at most 1000 μm, preferably at least 100 μm and at most 800 μm, particularly preferably at least 150 μm and at most 750 μm, when measured according to ISO 534:2011.

13. 13. The filter material according to any one of claims 1 to 12, wherein the filter material has a tensile strength across its width, measured according to ISO 1924-2:2008 in at least one direction, of at least 0.05 kN / m and at most 5 kN / m, preferably at least 0.07 kN / m and at most 4 kN / m.

14. 14. The filter material according to any one of claims 1 to 13, wherein the elongation at break of the filter material is at least 1% and at most 50%, preferably at least 3% and at most 40%, when measured according to ISO 1924-2:2008 in at least one direction.

15. A segment for nicotine delivery products, A segment that is a smoking article comprising the filter material according to any one of claims 1 to 14 and a packaging material that packages the filter material.

16. the segments are cylindrical in shape with circular base regions; 16. The segment according to claim 15, wherein the circular bottom region has a diameter of at least 3 mm and at most 10 mm, preferably at least 4 mm and at most 9 mm, particularly preferably at least 5 mm and at most 8 mm.

17. 17. The segment according to claim 15 or 16, wherein the segment has a length of at least 4 mm and at most 40 mm, preferably at least 6 mm and at most 35 mm, particularly preferably at least 10 mm and at most 28 mm.

18. 18. A segment according to any one of claims 15 to 17, wherein the resistance to draw per length of the segment is at least 1 mmWG / mm and at most 12 mmWG / mm, preferably at least 2 mmWG / mm and at most 10 mmWG / mm, when measured according to ISO 6565:2015.

19. The segment according to any one of claims 15 to 18, wherein the packaging material is paper or film.

20. The packaging material has a density of at least 20 g / m ２ And at most 150 g / m ２ , preferably at least 30 g / m ２ And at most 130 g / m ２ 20. The segment according to any one of claims 15 to 19, having a basis weight of

21. A smoking device comprising a segment, A smoking article comprising an aerosol-forming material and a segment according to any one of claims 15 to 20.

22. A smoking device as described in Claim 21, wherein the segment is positioned at the mouth end of the smoking device.

23. 23. The smoking article of claim 21 or 22, wherein the smoking article is a filter cigarette and the aerosol-forming material is tobacco.

24. 23. A smoking article according to claim 21 or 22, wherein the aerosol-forming material is heated only and does not burn during intended use of the smoking article, and the aerosol-forming material comprises tobacco, reconstituted tobacco, nicotine, glycerol, propylene glycol, or a mixture of two or more of these components.

25. 25. A smoking article according to any one of claims 21 to 24, wherein the wrapping material of the segment according to any one of claims 15 to 20 is at least partially transparent or has holes, and the filter material has a transparency of at least 50% when measured in accordance with DIN 53147:1993-01.

26. An oral nicotine delivery product comprising a pouch formed from the filter material of any one of claims 1 to 14 and containing a nicotine-containing material.

27. A method for producing a filter material, comprising steps A to D: A - providing a fibrous web comprising cellulose fibers; B - hydroentangling said fibrous web with at least one water jet directed at said fibrous web to produce a hydroentangled fibrous web; C - creating a structure within the hydroentangled fibrous web; D- drying the hydroentangled fibrous web; Including, the amount of cellulose fibers in step A is selected so that after drying in step D, the filter material comprises at least 50% by weight and at most 100% by weight of cellulose fibers, based on the weight of the filter material; After drying in step D, the filter material has a density of at least 25 g / m ２ And at most 60 g / m ２ and After drying in step D, the filter material has a structure characterized by providing the filter material with a transparency of at least 45% and at most 70%, as measured according to DIN 53147:1993-01; The creation of the structure in step C is carried out by directing at least one water jet at the fibrous web, the fibrous web being supported by a surface having a plurality of protrusions; method.

28. Step A includes spinning a plurality of cellulose fibers; The cellulose fibers are formed from filaments of regenerated cellulose, After drying in step D, at least 90% by weight of the filter material is formed by filaments of regenerated cellulose; 28. The method of claim 27.

29. Step A includes steps A1 to A4: A1 - Producing an aqueous suspension comprising cellulose fibers; A2 - applying said suspension from step A to a running wire; A3 - dewatering said suspension by said traveling wire to form a fibrous web; A4 - transferring said fibrous web from step A3 onto a supporting wire; 28. The method of claim 27, comprising:

30. 30. The method according to claim 29, wherein the aqueous suspension in step A1 has a solids content of at most 3.0%, preferably at most 1.0%, particularly preferably at most 0.2%, in particular at most 0.05%.

31. 31. The method according to claim 29 or 30, wherein the running wires of steps A2 and A3 are inclined upwards in the running direction to the horizontal at an angle of at least 3° and at most 40°, preferably at an angle of at least 5° and at most 30°, particularly preferably at an angle of at least 15° and at most 25°.

32. creating a pressure differential between the two sides of the running wire to support the dewatering of the suspension in step A3; 32. The method according to any one of claims 29 to 31.

33. A plurality of water jets are used to perform the hydroentanglement in step B; The method according to any one of claims 27 to 32, wherein the water jets are arranged in at least one row transverse to the running direction of the fibrous web.

34. The hydroentangling in step B is carried out by at least two water jets directed at the fiber web.

34. The method according to any one of claims 27 to 33.

35. The method according to any one of claims 27 to 34, wherein the fiber web in step C is supported by a cylinder, and a plurality of protrusions are arranged on the surface of the cylinder.

36. In step C, the area of ​​each protrusion protruding from the surface supporting the fiber web is at least 0.1 mm ２ And a maximum of 15 mm ２ , preferably at least 0.25 mm ２ And a maximum of 10 mm ２ The method according to any one of claims 27 to 35, wherein

37. 37. The method according to any one of claims 27 to 36, wherein the drying in step D is carried out at least in part by contact with hot air, by infrared radiation or by microwave radiation.

38. 38. The method according to any one of claims 27 to 37, wherein after drying in step D the filter material is a filter material according to any one of claims 1 to 14.

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