Filter materials for mouthpieces of smoking products or HNB products

Abstract

The present invention relates to a filter material and / or a filling material for a mouthpiece of a smoking product or HNB product, the filter material and / or the filling material being based on cellulose acetate filaments, at least some of which are in the form of hollow cellulose acetate filaments. The present invention also relates to a mouthpiece for a smoking product or HNB product, the mouthpiece comprising a filter material and / or a filling material of the type according to the present invention. The present invention also relates to a cigarette filter comprising such a filter material and / or a filling material, and a corresponding method for manufacturing a filter material and / or a filling material for a mouthpiece for a smoking product or HNB product.

Description

[0001] The present invention relates to a filter material and / or a filler material for a mouthpiece of a smoking product or a HNB product and the use of such a filter material and / or a filler material in a mouthpiece of a smoking product or in a cigarette filter or a mouthpiece of a HNB product, respectively. According to another aspect, the present invention relates to a method for manufacturing such a filter material and / or a filler material.

[0002] Smoking products in the sense of the present invention relate to conventional tobacco products, in particular cigarettes, but also pipes and so-called heat-not-burn (HNB) products, e-cigarette products and so-called hybrid products.

[0003] Mouthpieces for smoking products have different functions depending on the application. Firstly, mouthpieces can act as filtering means, for example in order to extract harmful elements such as condensed matter like tar and particulate matter entrained in the tobacco smoke flow from the smoke. This filtering function is particularly used in traditional tobacco applications. Thus, a corresponding mouthpiece can be formed as an integral part of a cigarette or a cigarillo and thus form a "tip" on the cigarette or cigarillo.

[0004] A replaceable device is another type of mouthpiece, which is a replaceable filter element that can be removed after use, for example. Such mouthpieces are placed on a suitable holder, such as a cigarette holder or a pipe holder.

[0005] One type of mouthpiece that forms an integral part of a cigarette is a cigarette filter. Cigarette filters are intended to suppress the percentage of harmful substances such as condensate and gases in cigarette smoke. In addition, for most smokers, the filter makes the smoke somewhat milder or more palatable. In traditional filter cigarettes, the filter is wrapped in a filter wrapper and connected to the tobacco roll with a so-called tipping paper, whereby most industrially manufactured cigarettes are provided with a filter. Those who roll their own cigarettes can purchase filters at tobacco shops.

[0006] Many types of filter materials have been used to reduce the concentration of substances, particularly in tobacco smoke, before they reach the smoker's respiratory system. However, in addition to removing a large number of harmful elements, a satisfactory filter also needs to be effective without undesirably obstructing the passage of air or smoke through the filter and thereby requiring excessive suction of the air or smoke. However, when used in tobacco smoke filters, the filter material must also not change the taste of the tobacco smoke by adding its own flavor.

[0007] Another important factor in producing a satisfactory tobacco smoke filter is that its manufacture should not be so complex as to unduly increase the final price of the smoking product in which the filter is used.

[0008] However, the present invention relates less to filter materials for the above-mentioned conventional tobacco applications, but in particular to filter materials and / or filling materials for mouthpieces of smoking products, wherein these filter materials and / or filling materials in particular have other functions in addition to a simple filtering function.

[0009] In other applications, the filtering function of the mouthpiece is actually not the main focus. This applies, for example, to heat-not-burn products ("HNB products") that have become increasingly popular in recent years. In these devices, a portion of the processed tobacco is heated by a heat source during use but is not burned. Volatile tobacco components such as flavorings, nicotine, glycerin and water are thereby vaporized and entrained in the air that the user inhales through the HNB product. As the released substances cool, an aerosol is formed, which is inhaled by the user.

[0010] Commercially available HNB products usually include a device consisting of a power supply for powering the heating element and a separate consumable product, which includes: a portion of processed tobacco, a support element (such as a tubular cellulose acetate segment), a so-called cooling element arranged downstream in the flow direction (for example in the form of a rolled polylactic acid film bundled into a cylinder with a plurality of axial channels), and a filter at the mouth side. The consumable product is inserted into the device before use so that the heating element heats a portion of the tobacco when the HNB product is used.

[0011] For example, in a product called IQOS / HEETS from Philip Morris, the tobacco is partially pierced by a heated blade in the device. IQOS / HEETS products refer to the IQOS device as sold by Philip Morris and its related consumable HEETS products. Consumable HEETS products are heat-not-burn products in which the tobacco is simply heated and not burned.

[0012] Competitive products from BAT ("Glo") heat tobacco externally, with the so-called cooling element replaced by a tube. Also in these devices, a portion of the processed tobacco is heated by a heat source during use but not burned. Volatile tobacco components such as flavors, nicotine, glycerin, and water are thereby vaporized and entrained in the air that the user inhales through the HNB product. As the released substances cool, an aerosol is formed, which is inhaled by the user.

[0013] Known consumable products for this application have the disadvantage that their mouthside filters may heat up significantly due to the proximity to the heating element and due to the hot vapor generated during use of the HNB product.

[0014] In so-called hybrid products, the aerosol generator first vaporizes (propylene glycol, glycerine); cooling produces an aerosol. This aerosol is directed through a portion of processed tobacco and inhaled by the consumer. Also in such applications, the mouthpiece has the special function of protecting the user's side from being heated to a degree that is unpleasant for the user.

[0015] Compared to conventional tobacco products that burn tobacco, it may be desirable that in the case of HNB product consumables, elements arranged downstream of the heated tobacco portion in the flow direction, such as cooling elements and mouth side filters, have only a low filtering effect on condensed components such as tar, since these components in the smoke may be present in significantly smaller amounts.

[0016] Therefore, the materials required to form the mouthpiece of the smoking product need to be adapted to, and in particular adaptable to, the physical properties (temperature, flow profile, etc.) and chemical composition of the smoke. Both conventional cigarette filters and HNB products in particular have a number of target parameters that need to be adjusted or met accordingly by appropriate selection and configuration of the mouthpiece material. This particularly relates to the following target parameters which will be briefly discussed below:

[0017] Suction resistance

[0018] Filtration performance

[0019] Filter rod hardness / Filtrona hardness

[0020] Visual appearance

[0021] Cost-effective production

[0022] Smoke temperature

[0023] Filter rod hardness is an important target standard for cigarette filters. It is typically indicated as the so-called Filtrona hardness. Filtrona hardness is determined by vertically pressing the flat front end of a cylindrical rod with a diameter of 12 millimeters (mm) onto a horizontally placed filter rod under a load of 300 grams (g). The ratio of the diameter after compression to the initial diameter measured at the first contact gives the Filtrona hardness percentage.

[0024] However, it is important to emphasize that Filtrona hardness is measured only on the filter, not on the underlying (original) filter material.

[0025] The minimum limit of the Filtrona hardness is about 88% and is adjusted to market requirements. Therefore, the Filtrona hardness of the cigarette filter can preferably be set to about 88% to 95%, in particular about 90% to 93%.

[0026] In conventional cigarette filters, the Filtrona hardness is essentially determined by the fiber weight per unit volume for a given filter diameter. In particular, the filament fineness has only a slight influence on the Filtrona hardness.

[0027] In some cases, a stronger filter wrapper or stronger tipping paper will also achieve a higher Filtrona hardness. Tipping paper is the paper that connects multiple filter elements together or connects a filter element to a tobacco rod. However, increasing Filtrona hardness by using a stronger filter wrapper or stronger tipping paper has an economic disadvantage because this approach can be expected to have a higher cost.

[0028] Related to Filtrona hardness is the so-called "thermal collapse", where the filter hardness decreases during smoking. This is particularly likely to occur in conventional cigarettes when the filter is heated in the presence of moisture during one of the last few puffs. This undesirable effect may also occur with HNB products.

[0029] In addition to a Filtrona hardness that is as constant and high as possible during use of the smoking product, the mouthpiece material should also exhibit a predetermined or definable filtration performance. The filtration performance with respect to condensed matter (droplets, particles) (also referred to as condensate or tar) is of concern for conventional tobacco products as well as HNB products, since condensed matter contains a variety of substances of unhealthy significance.

[0030] In conventional products, filter properties (and other influencing factors such as tobacco blend, ventilation, etc.) are selected to adjust the "give" of the cigarette (the concentration of smoke constituents in the mainstream smoke). In many markets, legal regulations limit the "give" to a certain upper limit. Below the legal limit, the "give" can be adapted to consumer preference.

[0031] In HNB products, the aerosol has much fewer condensed substances with negative health implications than in conventional products. However, since more desirable substances such as flavoring substances and nicotine are also present in the condensate, the aim here is to select the lowest possible filter performance without, however, allowing it to drop to zero.

[0032] It should be noted that consumers show preferences for a range of draw resistances when using tobacco products. In conventional cigarettes, the role of the filter (in addition to adjusting the "give") is to adjust the draw resistance of the cigarette.

[0033] However, in HNB products, the draw resistance contributed by the mouth-side filter (mouthpiece) should tend to be as low as possible, because other components of the HBN device, especially the tobacco and the heating part of the device, already provide a high contribution to the draw resistance. Low filter (mouthpiece) draw resistance leads to freedom in relation to other components of the HBN device, which is desirable.

[0034] However, suction resistance and filter performance are closely related. Both can be reduced in various ways, although this often has a negative impact on the other parameter.

[0035] For example, the suction resistance and filtration performance can be reduced by reducing the length of the filter. But once the filter length becomes smaller than the filter diameter, processability becomes problematic. Shorter filters also result in shorter cooling sections, which is problematic for thermal balance.

[0036] Alternatively or additionally, the suction resistance and the filtration performance can be reduced by reducing the fiber weight and / or the total denier number per volume content in the filter material. However, this has the disadvantage that the Filtrona hardness is reduced and the minimum hardness may no longer be achieved.

[0037] Alternatively or additionally, the suction resistance and the filter performance can be reduced by increasing the filament size. At a constant filter diameter and a fixed fiber weight per unit volume, the filter performance and the suction resistance decrease with increasing filament size, which is desirable in the case of HNB products compared to conventional products. The hardness is also not negatively affected, since, as mentioned above, the Filtrona hardness depends only to a small extent on the filament size.

[0038] It is noted with respect to the "visual appearance" target parameter that consumers prefer mouthpieces with a flat, white cross-sectional area at the mouth side. However, there are also products that are formed as a tube at the mouth side.

[0039] It is important to note with regard to the smoke temperature that the smoke temperature is not a problem in today's conventional products. However, in commercial HNB products, the smoke temperature is significantly high and to an uncomfortable level for some consumers. In addition, commercial HNB products require cooling in order to cool the vaporized components so that an aerosol of the gaseous components is initially formed.

[0040] In commercially available HNB products, the distance from the heating element of the HNB product to the mouth end is undoubtedly the most important parameter for cooling the aerosol. Thus, for example, it is known to arrange a so-called cooling element downstream of the tobacco portion and the support element. The cooling element can be in the form of a rolled polylactic acid film or in the form of a cardboard tube, whereby, in addition to cooling, the element arranged downstream of the tobacco portion and the support element also play the role of a spacer providing mechanical stability.

[0041] Finally, the mouthpiece material must meet the target parameters of cost-effectiveness. In particular, a suitable mouthpiece material is needed that can be produced with the lowest possible material usage and the lowest possible processing cost.

[0042] Although conventional cigarette filters, which usually consist of cellulose acetate filaments, ensure optimal filtration of smoke components, these filter materials can often only be used to a limited extent in other applications, in particular in the case of HNB products or e-cigarettes, where the filter material or respectively the mouthpiece material needs to assume other functions.

[0043] HNB products, as well as conventional smoking products, generally have the disadvantage that the user inhales the inhalation aerosol at a high temperature. This is sometimes uncomfortable for the user. Especially for HNB products, the mouthpiece material therefore has the task of cooling the aerosol with the lowest possible filter performance.

[0044] But also in the case of conventional cigarettes, especially so-called slim or super slim cigarettes; i.e. small diameter cigarettes of e.g. 5.0 mm to 6.5 mm, the filter material / mouthpiece material needs to provide reduced filtration performance, increased cooling and improved tactile properties (firm grip but not too hard) compared to the filter material of large size cigarettes. Naturally, the smoke / flavor when burning is less than that of large size cigarettes. Low filtration performance is sought in order not to further reduce the flavor. If the amount of filter material is simply reduced for this purpose, the filter hardness will eventually become insufficient.

[0045] At the same fiber density, filters for slim or superslim cigarettes also have significantly higher draw resistance than larger size filters, which is generally undesirable.

[0046] For HNB products as well as ultra-slim cigarettes, it has been proposed to increase the filament fineness while maintaining the total fineness in order to achieve a desirable reduced filtration performance and sufficient filter hardness in terms of condensable components such as tar. However, this approach has the disadvantage that such high filament fineness fiber materials have an economic disadvantage for conventional spinning machines. In the production of conventional filter tow, a solution of approximately 30% cellulose-2,5-acetate in acetone is extruded through a spinneret, the acetone is evaporated in a spinning chamber by blowing heated air over it, and a large number of filaments (1,000 to 35,000) are then gathered into strips and curled in a material box. In the case of higher filament fineness, a larger volume of solvent needs to be evaporated per filament, which requires more time and results in slower spinning speeds due to the larger ratio of filament cross-sectional area to filament surface area.

[0047] Based on this problem, the present invention is directed to providing a material suitable for a wide range of smoking product applications.

[0048] Specifically, the object of the present invention is to provide a filter material with low suction resistance and low filter performance, wherein the filter material can achieve a sufficiently high Filtrona hardness, which is as constant as possible when used in smoking products and wherein the filter material can still be produced particularly cost-effectively.

[0049] Furthermore, the filter material should be suitable for producing a filter having a uniform, white and flat front end on the mouth side.

[0050] In this context, it is further desirable that the filter material exhibits a selective filtration effect for phenol.

[0051] The filter material should be particularly suitable for reliably cooling heated particle-laden gases so as to be able to reduce the temperature of the gases, aerosol or vapor inhaled by a user from the smoking product.

[0052] Furthermore, the material should be selected so that when used as filter material, in particular for slim or ultra-slim cigarettes, an adjustable resistance to drawing can be achieved and in particular a reduced resistance to drawing compared to filters of larger dimensions.

[0053] The subject matter of the present invention provides a solution to these and other tasks.

[0054] The present invention therefore relates in particular to a material for forming a mouthpiece of a smoking product, wherein the material comprises a filling material based on cellulose acetate filaments which are at least partially formed as hollow cellulose acetate filaments. The filling material partially formed as hollow cellulose acetate filaments has a lower density and a higher filling value than conventional cellulose acetate filaments which are not of hollow design and which are usually used in cigarette filters. The provision of such a filling material enables a significant increase in the range of properties and applications that can be achieved with a mouthpiece.

[0055] The term "hollow fiber" as used herein is to be understood in particular as a cylindrical fiber which preferably has one or more continuous hollow regions in cross section. The hollow fibers are preferably at least partially curled. However, the invention is not limited to curled hollow fibers, but also relates to non-curled fibers or their respective use.

[0056] According to an embodiment variant of the invention, the hollow fibers are at least partially realized as multi-lumen hollow fibers. Compared to single-lumen hollow fibers, multi-lumen hollow fibers have a significantly higher kink resistance, whereby a particularly high Filtrona hardness can be achieved without increasing the compaction of the material.

[0057] The term "Filtrona hardness" as used herein is understood to be the hardness of the filter determined according to the Filtrona principle. The principle involves determining the hardness of the filter by vertically pressing the flat front end of a cylindrical rod with a diameter of 12 mm onto a horizontally placed filter rod under a load of 300 grams. The ratio of the diameter after compression to the initial diameter measured at the first contact gives the Filtrona hardness percentage.

[0058] According to a preferred embodiment of the invention, the cellulose acetate filaments in hollow form present a cross-sectional shape that is at least partially trilobal; i.e. a three-armed star. Such a cross-sectional shape is very suitable when the cellulose acetate filaments have the largest possible specific surface area, in order to achieve, for example, a high filtration capacity and at the same time an economical use of the raw material. Alternatively to this, a bundle of very fine filaments of circular cross section can be used to obtain the desired large specific surface area. However, other cross-sectional shapes of the hollow cellulose acetate filaments are also conceivable, such as, for example, a four-sided cross-sectional shape.

[0059] The filter material and / or filler material of the present invention is economical to produce and can be processed alone or together with conventional non-hollow cellulose acetate filaments into filter rods having suitable suction resistance and optimized filtering properties.

[0060] Since the filter and / or filling material according to the invention comprises a filling material based on cellulose acetate filaments which are at least partially in the form of hollow cellulose acetate filaments, low suction resistance and low filter performance can be achieved, since the filaments of the filter and / or filling material in the form of at least partially hollow cellulose acetate filaments have a small outer surface area relative to the total fiber volume. It is preferred here that the filaments of the filter and / or filling material in the form of at least partially hollow cellulose acetate filaments exhibit a cross section that is as round as possible.

[0061] Against this background, it has surprisingly been found that filter materials and / or filler materials can achieve particularly high Filtrona hardnesses due to the filaments being in the form of at least partially hollow cellulose acetate filaments. In fact, it has been found that filters formed at least partially of hollow cellulose acetate filaments (hollow fibers) can achieve the desired minimum Filtrona hardness at a relatively low fiber weight per unit volume.

[0062] Based on cellulose acetate filaments, the filter material and / or filler material of the present invention is suitable for producing a filter having a uniform, white and flat mouth-side front end, whereby a selective phenol filtering effect can further be achieved.

[0063] In terms of smoking and health dialogue, the use of filtering and / or filling materials based on cellulose acetate filaments firstly enables the production of filter rods, in particular filter rods for cigarettes, which have clearly outstanding properties with respect to specific retention phenomena. Thus, the filtering efficiency of filters made of cellulose acetate for harmful nitrosamines and phenols is much higher than for condensate and nicotine. In addition, smokers rate the taste of today's common tobacco mixtures such as "American blend", "German blend" and "Virginia" in combination with filter rods made of cellulose acetate as the most pleasant. Another advantage of cellulose acetate filter rods that should not be underestimated can be derived from the optical homogeneity of the cut surface of the filter.

[0064] By forming the filter material and / or the filling material of the invention at least partially from hollow cellulose acetate filaments as filling material, a wide range of different suction resistances and filtration properties is possible in filter rods made from the material of the invention.

[0065] In particular, it has been shown that filter materials consisting at least partially of hollow cellulose acetate filaments exhibit an improved thermal cooling effect. It has been determined that, for the suspended matter and gases to be removed, the use of hollow cellulose acetate filaments as filling material still enables a very low filter effect to be achieved; i.e. a retention effect. It is assumed that this effect is achieved by the surface blowing or flow of the gas or air to be cleaned being altered by the hollow cellulose acetate filaments in such a way that any potential suspended matter in the gas / air is retained only to a small extent. Another reason may be that the use of hollow cellulose acetate filaments enables a different, particularly advantageous surface structure of the filter material to be achieved.

[0066] The filter material and / or filler material according to the invention further has the advantage that a particularly adjustable cooling of heated particle-laden gases, in particular aerosols, is possible, so that the temperature of the gases, aerosols or vapors inhaled by the user of the smoking product or HNB product can be reduced in a targeted manner. By varying the proportion of hollow cellulose acetate filaments in the filter and / or filler material, the desired cooling effect can thus be specifically adapted to the application.

[0067] It is more important to note that in the filter material and / or filling material of the invention, the gas flow is substantially around and less through the hollow cellulose acetate filaments (= hollow fibers). From geometrical considerations, it is obvious that the distance between fibers is thus significantly greater than the lumen (hollow part) of the hollow fibers. The viscosity of the aerosol (essentially air) is then such that the gas takes the path of least resistance (i.e. flows between the filaments, rather than through each individual filament).

[0068] In other words, in the filter material and / or filling material of the present invention, the effective filter surface is by no means maximal, since there is no flow through the hollow cellulose acetate filaments in the filter and / or filling material.

[0069] In particular, the hollow cellulose acetate filaments can therefore have kinks which close the lumen of the hollow cellulose acetate filaments without this having an influence on the properties of the filtering and / or filling material according to the invention with respect to the set target parameters.

[0070] In this context it is particularly important to note that hollow cellulose acetate filaments designed as hollow fibers are not necessarily continuously hollow but can also be partially closed by kinks. They can also deviate from an ideal circular shape.

[0071] Embodiments of the present invention provide hollow cellulose acetate filaments as a support material on the one hand and as a filter material and / or filler material as a cooling material on the other hand. By hollow cellulose acetate filaments that are simultaneously a support material, a particularly compact mouthpiece can be achieved, thereby not requiring an increase in the size of the smoking product.

[0072] For example, it is conceivable that the filter material and / or the filling material presents adjacent areas of hollow cellulose acetate filaments and non-hollow cellulose acetate filaments in the longitudinal direction of the mouthpiece. A mixture of hollow and non-hollow cellulose acetate filaments would also be conceivable. Alternatively or additionally to this, hollow and non-hollow cellulose acetate filaments can be arranged in layers and then curled. In this way, the maximum possible area of ​​hollow cellulose acetate filaments as cooling material is achieved, thereby better cooling the gas containing particles.

[0073] The filter material and / or the filler material can be introduced into the smoking article in such a way that, in particular, the hollow cellulose acetate filaments are arranged substantially longitudinally to the flow direction of the particle-laden gas or aerosol. This can thereby achieve that when a user sucks on the mouthpiece, the filter and / or filler material only generates a reduced pressure drop, so that the user does not find the sucking action difficult or unpleasant. By varying the alignment of the hollow cellulose acetate filaments relative to the flow direction of the particle-laden gas or aerosol, the suction resistance of the filter material and / or filler material can be varied within a wide range and adapted to the respective application.

[0074] Changing the ratio of hollow and non-hollow cellulose acetate filaments in the filter and / or filling material and / or changing the alignment of the hollow and non-hollow cellulose acetate filaments in the filter and / or filling material relative to the flow direction of the gas or aerosol containing particles can not only adjust the cooling and filtration performance, but also adjust the suction resistance of the filter material and / or filling material.

[0075] Alternatively, a filter and / or filler material consisting only of hollow cellulose acetate filaments is provided. The filter and / or filler material then achieves an optimal cooling efficiency at reduced filter performance.

[0076] Another embodiment of the filter material and / or filler material of the present invention provides that the filter and / or filler material is arranged in front of the cigarette holder as a separate segment in the flow direction of the gas or aerosol containing particles. The separate segment can be of various shapes. Although a cylindrical shape is described as a preferred embodiment, the present invention is not limited to this. Conventional smoking products are usually substantially cylindrical in design. The separate segment can thus be further arranged in front of any possible filter in the flow direction of the gas containing particles. The filter and / or filler material as a cooling device and formed as a separate segment can, for example, be composed entirely of hollow cellulose acetate filaments.

[0077] It is also conceivable that the individual segments comprise a wrapper or shell type made of, for example, paper, so that the hollow cellulose acetate filaments as cooling material can be encapsulated. The wrapper or shell has an inlet and an outlet, respectively, for the gas / aerosol containing particles, through which the gas / aerosol containing particles flows due to the suction generated by the user's mouthpiece. The hollow cellulose acetate filaments as cooling material can also be selectively fixed in or respectively on the smoking product, for example in the form of an encapsulation. In this way, the user can choose to cool only the gas containing particles, if the user deems it necessary to do so.

[0078] As already stated, the suction resistance of filter rods formed in particular from the filter material according to the invention can be varied within a much wider range by varying the proportion of hollow cellulose acetate filaments in the filter material.

[0079] In summary, it can therefore be said that by using a filter material consisting at least partially of hollow cellulose acetate filaments, the scope for adapting the suction resistance and the filter performance to the respective requirements is wide and this is clearly more flexible than is the case with conventional filter materials based on cellulose acetate filaments. In addition, the cooling effect can be variably adjusted.

[0080] The present invention particularly allows the mouthpiece or filter, respectively, to be formed from cellulose acetate, typically in the form of a strand of substantially longitudinal continuous filaments, wherein the continuous filaments are preferably curled so that the short cross-sections of the individual filaments are irregularly arranged in non-parallel, converging and diverging directions compared to the main longitudinal direction of the strand.

[0081] In a possible embodiment of the filter material according to the invention, the surface structure of the filter material can be modified by using particularly curled cellulose acetate filaments. The curl index of the cellulose acetate filaments is preferably between 10% and 60%, and in particular between 20% and 50%.

[0082] Curl Index I x Is a measure of the crimp strength. The crimp index of filter tow is determined by tensile testing (force / strain relationship). It is defined as the ratio of the stretched length L2 minus the initial length under the test load to the initial length L1 under preload:

[0083] I x =(L2-L1) / L1*100%

[0084] The test load is thus 25 N and the preload is 2.5 N. The curl length is 250 mm. The curl index is determined in a tensile test at a constant strain rate of 300 mm / min on a G02 apparatus from the Borgwaldt GmbH company in Hamburg. Ten individual measured values ​​are recorded for each measurement. The tests are carried out in a standard climate of 20° C. and 60% relative humidity.

[0085] The filter material of the invention is preferably in the form of a filter tow consisting of continuous cellulose acetate filaments, and in particular cellulose-2,5-acetate filaments, which have been crimped in a material box. To produce the filter tow, a solution of about 30% cellulose-2,5-acetate in acetone is extruded through a special spinneret, the acetone is evaporated in a spinning chamber by blowing heated air over it, and a large number of filaments (1,000 to 35,000) are then gathered into strips and crimped in a material box. The product is then dried, packed into storage containers and finally pressed into bales weighing between 300 and 600 kg.

[0086] The spinneret is used to spin the spinning solution, and the spinneret is designed to spin hollow cellulose acetate filaments and / or cellulose acetate staple fibers.

[0087] After the filter tow packages have been delivered to the filter or cigarette manufacturer, the filter filaments are removed from the packages and processed into filter rods on a filter rod machine as described, for example, in the printed publication US 5,460,590 A. The filter tow is thus stretched in a stretching device equipped with an additive for binding the filaments and then, after forming a three-dimensional yarn bundle, is fed through an inlet funnel to a formatting unit where the three-dimensional yarn bundle is compressed axially crosswise, wrapped in paper and cut into filter rods of final length.

[0088] The additive for bonding the filaments can be a high boiling point solvent for cellulose acetate such as triacetin, for example, which dissolves the surface of the filaments briefly after application. As long as two filaments come into contact, the solution droplets before are solidified as the excess additive migrates to the fiber surface, and permanent bonding points appear for a period of time thereafter. Due to the migration of the above-mentioned hardener, a filter rod with high mechanical strength and three-dimensional cross-linking is obtained after a storage period of less than one hour. The filter rod is also referred to as a "space filter" and has a low packing density of typically 20 mg / ml to 90 mg / ml, preferably 30 to 70 mg / ml and more preferably 40 to 60 mg / ml. Due to its hardness, these filter rods can be processed at high speed without difficulty on modern cigarette machines.

[0089] Tests have shown that using hollow cellulose acetate filaments in the filter material can reduce the filtration performance of the spatial filter while maintaining specifications such as length, diameter, suction resistance and filament fineness, and improve cooling efficiency.

[0090] By correspondingly increasing the proportion of hollow fibers (hollow-shaped cellulose acetate filaments) in the filter material, the suction resistance can be maintained within a desired low range without increasing the filament fineness, although the cooling efficiency is increased and the filtering performance is reduced.

[0091] According to the realization of the filter material according to the invention, it is therefore particularly provided that the percentage of hollow (hollow) cellulose acetate filaments in the filter material is between 20% and 100% and preferably between 40% and 100% and more preferably (depending on the application) between 70% and 100%.

[0092] In particular, the hollow portion in the filter material is preferably 25% to 90% and preferably 50% to 80%. The hollow portion makes a significant contribution to the filter performance on the one hand and reduces the suction resistance on the other hand, which is only possible through an appropriate proportion of hollow fibers in the filter material, but cannot be achieved with closed filaments. Thus, the hollow portion corresponds to the ratio of the "hollow" area of ​​the filter material to the "total" cross-sectional area of ​​the fibers.

[0093] In this context it should be noted that the filter material according to the invention is also characterized in particular in that the filament diameter of the cellulose acetate filaments is significantly greater than the filament diameter of other (synthetic) hollow fibers, which have a filament diameter in the range between 10 and 30 μm. In contrast, the filament diameter of the hollow cellulose acetate filaments ranges between 30 and 150 μm (outer diameter), and preferably between 50 and 120 μm (outer diameter), and more preferably between 60 and 100 μm (outer diameter). In this way, the hollow portion can be increased and thus the specific filter performance of the filter material and / or filling material according to the invention is significantly reduced, while at the same time the cooling efficiency of the filter material and / or filling material according to the invention is increased.

[0094] The invention further relates to a cigarette filter made of a filter material of the above-mentioned type.

[0095] According to non-limiting examples, water-soluble binders can be used to produce the filter according to the invention both in the case of thermoplastic cellulose ester fiber materials and in the case of non-thermoplastic cellulose esters. In the first case of thermoplastic cellulose ester fiber materials, a distinction can be made between two cases. In the first case, the fiber material is produced from a natural thermoplastic cellulose ester such as, for example, cellulose acetate butyrate. No further measures are required here to process the filter tow into the filter according to the invention. For non-thermoplastic base polymers such as cellulose-2,5-acetate, for example, it needs to be thermoplasticized by adding a suitable plasticizer.

[0096] To produce the filter of the invention, the filter tow is pulled from the bag, pneumatically unrolled and stretched in the customary manner for spatial filters.

[0097] In the context of the present teaching, the acetate weight may be at most 5 mg per mm filter length and at least about 2 mg per mm filter length, and in particular about 3 to 4 mg per mm filter length. If the maximum value of 5 mg per mm filter length is exceeded, such a product is not sufficiently economical. Preferably, a minimum value of about 2 mg per mm filter length is maintained. According to the prior art, failure to achieve this value results in the fact that the desired minimum cigarette filter hardness of 88% can no longer be maintained.

[0098] In the context of the present teaching, the inhalation resistance may be at most 2 daPa per mm filter length and at least about 0.1 daPa per mm filter length, and in particular 0.2 daPa to 1 daPa per mm filter length. A inhalation resistance of 0.3 daPa to 0.7 daPa per mm filter length is particularly preferred. A minimum value of 0.3 daPa per mm filter length is preferably maintained. According to the prior art, failure to achieve this value results in the cigarette filter hardness of the desired minimum of 88% no longer being maintained.

[0099] Several aspects essential to the present invention are summarized below:

[0100] According to a first aspect, the present invention relates to a filter material and / or filler material for a mouthpiece of a smoking product or HNB product, wherein the filter and / or filler material is based on cellulose acetate filaments which are at least partially formed as hollow and / or tubular cellulose acetate filaments.

[0101] According to one embodiment variant of the filter material and / or the filling material, the cellulose acetate filaments comprise hollow and in particular crimped continuous cellulose acetate filaments and / or hollow and in particular crimped and cut continuous cellulose acetate filaments.

[0102] According to one embodiment variant of the filter material and / or the filling material, the curl index of the cellulose acetate filaments is between 10% and 60%, in particular between 20% and 50%.

[0103] According to one embodiment variant of the filter material and / or filling material, the cellulose acetate filaments are formed from a thermoplastic cellulose material, wherein the cellulose acetate filaments contain a uniformly distributed thermoplastic cellulose material, provided that a plasticizer is incorporated, and / or wherein a water-soluble binder is present on the surface of the cellulose acetate filaments.

[0104] According to one embodiment variant of the filter material and / or the filling material, when a plasticizer is used, the content of the plasticizer is between 1% and 40%.

[0105] According to one embodiment variant of the filter material and / or the filling material, when a plasticizer is used, the plasticizer is triacetin, triethylene glycol diacetate and / or diethyl citrate.

[0106] According to one embodiment variant of the filter material and / or the filling material, the cellulose acetate filaments have a fineness between 5 and 30 denier, preferably between 10 and 25 denier and more preferably between 15 and 20 denier.

[0107] According to one embodiment variant of the filter material and / or filler material, the total denier of the filter and / or filler material is between 4,000 and 40,000 denier and preferably between 6,000 and 30,000 denier.

[0108] According to one embodiment variant of the filter material and / or filling material, the hollow parts in the filter material and / or filling material - relative to a cross section orthogonal to the fibers of the filter and / or filling material - amount to 25% to 90% and preferably 50% to 80%.

[0109] According to one embodiment variant of the filter material and / or filler material, the filament diameter of the cellulose acetate filaments ranges between 30 and 150 μm (outer diameter), preferably between 50 and 120 μm (outer diameter), and more preferably between 60 and 100 μm (outer diameter).

[0110] According to one embodiment variant of the filter material and / or the filling material, the mass ratio of the hollow cellulose acetate filaments is between 20% and 100%, preferably between 50% and 100% and more preferably between 70% and 100%.

[0111] According to one embodiment variant of the filter material and / or filler material, the hollow cellulose acetate filaments are spaced apart from one another in an irregular arrangement, whereby the cellulose acetate filaments are cross-linked and whereby the connected cellulose acetate filaments are entangled and / or tangled with one another.

[0112] According to an embodiment variant of the filter material and / or the filling material, a binder, in particular an organic or inorganic binder, is further provided for binding the cellulose acetate filaments.

[0113] According to another aspect, the present invention relates to a mouthpiece for a smoking product or HNB product, wherein the mouthpiece comprises a filter material and / or a filler material of the type described above.

[0114] According to a further aspect, the invention relates to a cigarette filter or a cigarette filter element having a filter material and / or a filling material of the type described above according to the invention.

[0115] According to an embodiment variant of the cigarette filter or the cigarette filter element, respectively, at least one of the following features is achieved:

[0116] The fiber density of the filter material and / or the filling material is between 10 and 70 kg per cubic meter and preferably between 20 and 70 kg per cubic meter and more preferably between 40 and 60 kg per cubic meter;

[0117] The cigarette filter or cigarette filter element has a Filtrona hardness of at least 88% and preferably a Filtrona hardness of 88% to 95% and more preferably a Filtrona hardness of 90% to 93%;

[0118] The cigarette filter or cigarette filter element has a resistance to draw of at least 0.1 decaPascals per mm filter length and preferably a resistance to draw of 0.2 to 1.0 decaPascals per mm filter length and more preferably a resistance to draw of 0.3 to 0.7 decaPascals per mm filter length;

[0119] The filter material and / or the filling material contains a plasticizer, wherein the content of the plasticizer is between 1% and 40%.

[0120] According to an embodiment variant of the cigarette filter / cigarette filter element, a flavour release element, in particular capsule-shaped or encapsulated, is further incorporated into the filter material and / or the filling material.

[0121] According to an embodiment variant of the cigarette filter / cigarette filter element, the cigarette filter or the cigarette filter element, respectively, comprises, in addition to the hollow cellulose acetate filaments, solid cellulose acetate filaments.

[0122] According to another aspect, the invention relates to the use of the filter and / or filler material of the invention in a smoking product or in a HNB product.

[0123] According to another aspect, the present invention relates to a method for manufacturing a filter material and / or a filling material for a mouthpiece of a smoking product or an HNB product, wherein the filter material and / or the filling material preferably consists of cellulose acetate filaments and / or cellulose acetate staple fibers, wherein a solution of cellulose acetate in acetone having an acetyl value of at least 53% is extruded through a spinneret having a plurality of openings, and thereby the cellulose acetate filaments are subsequently cut into cellulose acetate staple fibers as required, and thereby the large number of cellulose acetate filaments and / or cellulose acetate staple fibers thus obtained are gathered into a filter tow, which filter tow may be crimped if appropriate, wherein the spinneret through which the cellulose acetate solution is extruded is designed so that hollow cellulose acetate filaments are spun out.

Claims

1. A method for manufacturing a filter material and / or a filling material for a mouthpiece of a smoking product or an HNB product, the filter material and / or the filling material consisting of cellulose acetate filaments, the cellulose acetate filaments being at least partially formed as hollow cellulose acetate filaments, wherein a solution of cellulose acetate in acetone having an acetyl value of at least 53% is extruded through a spinneret having a plurality of openings, and wherein a large number of the cellulose acetate filaments are gathered into a filter tow, wherein the spinneret through which the cellulose acetate solution is extruded is designed so that the hollow cellulose acetate filaments are spun out, wherein the ratio of the hollow area in the filter material and / or the filling material to the total cross-sectional area of ​​the fibers of the filter material and / or the filling material is 25% to 90%, and wherein the filament diameter of the cellulose acetate filaments ranges between 60 and 100 µm.

2. The method according to claim 1, The ratio of the hollow area in the filter material and / or the filling material to the total cross-sectional area of ​​the fibers of the filter material and / or the filling material is 50% to 80%.

3. The method according to claim 1, The cellulose acetate filaments are curled, wherein the curl index of the cellulose acetate filaments is between 10% and 60%.

4. The method according to claim 3, The curl index of the cellulose acetate filaments is between 20% and 50%.

5. The method according to claim 1, wherein the cellulose acetate filaments contain a uniformly distributed plasticizer; and / or A water-soluble binder is present on the surface of the cellulose acetate filaments.

6. The method according to claim 1, wherein the cellulose acetate filaments comprise a plasticizer, and wherein the plasticizer is triacetin, triethylene glycol diacetate and / or diethyl citrate.

7. The method according to claim 1, The cellulose acetate filaments have a fineness between 5 and 30 deniers.

8. The method according to claim 1, The cellulose acetate filaments have a fineness between 10 and 25 deniers.

9. The method according to claim 1, The cellulose acetate filaments have a fineness between 15 and 20 deniers.

10. The method according to claim 1, The total fineness of the filter material and / or filler material is between 4,000 and 40,000 denier.

11. The method according to claim 1, The total fineness of the filter material and / or the filling material is between 6,000 and 30,000 denier.

12. The method according to claim 1, wherein the hollow cellulose acetate filaments are spaced apart from one another in an irregular arrangement, and wherein the cellulose acetate filaments are cross-linked, whereby the connected cellulose acetate filaments are entangled and / or tangled with one another.

13. The method according to claim 1, A binder is further provided for bonding the cellulose acetate filaments.

14. The method according to claim 13, The binder is an organic or inorganic binder.

15. A mouthpiece for a smoking product or a HNB product, wherein the mouthpiece comprises a filter material and / or a filler material manufactured according to the method of claim 1.

16. The mouthpiece according to claim 15, wherein the fiber density of the filter material and / or the filling material is between 10 and 70 kg per cubic meter; and / or wherein the mouthpiece has a Filtrona hardness of at least 88%; and / or The mouthpiece has a draw resistance of at least 0.1 decapsular per millimeter of filter length.

17. The mouthpiece according to claim 16, The fiber density of the filter material and / or the filling material is between 20 and 70 kilograms per cubic meter.

18. The mouthpiece according to claim 17, The fiber density of the filter material and / or the filling material is between 40 and 60 kilograms per cubic meter.

19. The mouthpiece according to claim 16, The mouthpiece has a Filtrona hardness of 88% to 95%.

20. The mouthpiece according to claim 19, The mouthpiece has a Filtrona hardness of 90% to 93%.

21. The mouthpiece according to claim 16, The mouthpiece has a draw resistance of 0.2 to 1.0 decaPascals per millimeter of filter length.

22. The mouthpiece according to claim 21, The mouthpiece has a draw resistance of 0.3 to 0.7 decaPascals per millimeter of filter length.

23. The mouthpiece according to claim 15, Capsule-shaped flavor release elements are further incorporated into the filter material and / or the filling material.

24. The mouthpiece according to claim 15, The filter material and / or the filling material comprises solid cellulose acetate filaments in addition to the hollow cellulose acetate filaments.

25. A cigarette filter or cigarette filter element comprising a filter material and / or a filler material produced according to the method of claim 1.

26. A cigarette filter or cigarette filter element according to claim 25, wherein the fiber density of the filter material and / or the filling material is between 10 and 70 kg per cubic meter; and / or wherein the cigarette filter or cigarette filter element has a Filtrona hardness of at least 88%; and / or The cigarette filter or cigarette filter element has a resistance to draw of at least 0.1 decapsular per millimeter of filter length.

27. A cigarette filter or cigarette filter element according to claim 26, The fiber density of the filter material and / or the filling material is between 20 and 70 kilograms per cubic meter.

28. A cigarette filter or cigarette filter element according to claim 27, The fiber density of the filter material and / or the filling material is between 40 and 60 kilograms per cubic meter.

29. A cigarette filter or cigarette filter element according to claim 26, The cigarette filter or cigarette filter element has a Filtrona hardness of 88% to 95%.

30. A cigarette filter or cigarette filter element according to claim 29, The cigarette filter or cigarette filter element has a Filtrona hardness of 90% to 93%.

31. A cigarette filter or cigarette filter element according to claim 26, The cigarette filter or cigarette filter element has a draw resistance of 0.2 decaPascal to 1.0 decaPascal per millimeter of filter length.

32. A cigarette filter or cigarette filter element according to claim 31, The cigarette filter or cigarette filter element has a draw resistance of 0.3 decaPa to 0.7 decaPa per millimeter of filter length.

33. A cigarette filter or cigarette filter element according to claim 25, Capsule-shaped flavor release elements are further incorporated into the filter material and / or the filling material.

34. The cigarette filter or cigarette filter element of claim 25, wherein the cigarette filter or cigarette filter element, respectively, comprises solid cellulose acetate filaments in addition to the hollow cellulose acetate filaments.