Filter element for mouthpieces, mouthpiece for use in smoking products or hnb products, and cigarette filter

Abstract

The invention relates to a filter element for mouthpieces for use with smoking products or HNB products, the filter element having a filter body made of a tow material, the tow material being formed by a plurality of individual threads of cross-linked and crimped cellulose acetate filaments, the cellulose acetate filaments having in particular a multilobal or polygonal and preferably Y-shaped cross-sectional geometry. According to the invention: the cellulose acetate filaments of the tow material have a uniform filament titre, which is in particular predetermined or predefinable, in a range of less than or equal to 10 denier (11.1 dtex) and greater than or equal to 5 denier (5.5 dtex); the tow material has a total titre in a range of less than or equal to 10,000 denier (11.1 kdtex) and greater than or equal to 5,000 denier (5,555.5 dtex); and the specific fibre weight of the cellulose acetate filaments of the tow material is less than or equal to 2.5 mg per mm of filter element length and greater than or equal to 1.0 mg per mm of filter element length.

Description

[0001] The invention relates to a filter element for mouthpieces for use with tobacco products or HNB products, and to the use of such a filter element in mouthpieces for tobacco products or in cigarette filters or in mouthpieces for HNB products.

[0002] Tobacco products within the meaning of the present invention relate to classic tobacco products, in particular cigarettes, but also pipes and marijuana products as well as so-called Heat-Not-Burn (HNB) products, vaping products and so-called hybrid products.

[0003] Depending on the application, mouthpieces for smoking products serve different functions. Firstly, mouthpieces can act as filters to remove harmful components from tobacco smoke, such as condensed substances, especially tar, as well as particulate matter carried along by the smoke. This filtering function is particularly important in traditional tobacco products. In such cases, a mouthpiece can be an integral part of a cigarette or cigarillo, thus providing support for the cigarette or cigarillo.

[0004] Another type of mouthpiece is the replaceable device, such as replaceable filter elements that can be removed after use. Such mouthpieces are held in appropriate holders, for example, in a cigarette holder or a pipe mouthpiece.

[0005] The mouthpiece, an integral part of a cigarette, is the cigarette filter. The filter is designed to reduce the amount of harmful substances, such as condensate and gas, in the cigarette smoke. Furthermore, the filter makes the smoke feel milder or more pleasant to many smokers. In a classic filter cigarette, the filter is encased in filter paper and attached to the tobacco strand with a tipping paper; most industrially manufactured cigarettes are equipped with a filter.

[0006] Numerous types of filter materials are already in use, particularly to reduce the concentration of harmful substances in tobacco smoke before they reach the smoker's respiratory system. In addition to removing large quantities of these harmful components, a satisfactory filter must also be effective without unduly restricting the passage of air or smoke through it, thus requiring an excessively strong draw. Furthermore, when using tobacco smoke filters, the filter material must not alter the taste of the tobacco smoke by imparting its own flavor.

[0007] The present invention relates not only to filter materials for the previously described classic tobacco applications, but in particular also to filter materials or filter elements for mouthpieces for the use of smoking products, wherein these filter elements have in particular functions other than just a filtering function.

[0008] The materials required for forming a mouthpiece for smoking products must therefore be adapted to, and in particular adaptable to, the physical properties of the smoke (temperature, flow profile, etc.) and its chemical composition. Specifically, both conventional cigarette filters and HNB products have a number of target parameters that must be set or met through the appropriate selection and configuration of the mouthpiece materials. These target parameters are, in particular, the following and will be briefly discussed below: Tensile resistance, filtration performance, filter rod hardness / filter hardness, optics

[0009] Filter rod hardness is an important criterion for cigarette filters. It is usually expressed as the so-called filtrona hardness. Filtrona hardness is determined by pressing a cylindrical rod with a diameter of 12 mm vertically, with its flat end facing down, onto a horizontally positioned filter rod using a load of 300 g. The ratio of the compressed diameter to the initial diameter determined by the first contact yields the percentage of filtrona hardness.

[0010] It should be emphasized that the filter hardness is measured only on the filter itself, not on the underlying filter (raw) material. In particular, the triacetin sprayed onto all cigarette filters affects the filter hardness.

[0011] The minimum filter hardness limit is approximately 88% and is based on market requirements. The filter hardness of the cigarette filter can preferably be set to approximately 88% to 95%, and particularly to approximately 90% to 93%.

[0012] In conventional cigarette filters, for a given filter diameter, the filter hardness is essentially determined by the fiber weight per unit volume. In particular, the filament titer has only a minor influence on the filter hardness.

[0013] Occasionally, a higher filtration hardness is also achieved by using a thicker filter wrapping paper or a thicker tipping paper. A tipping paper is a paper used either to connect multiple filter elements together or to connect filter elements to the tobacco strand. However, increasing the filtration hardness by using a thicker filter wrapping paper or a thicker tipping paper has economic disadvantages, as this approach is expected to result in higher costs.

[0014] Related to filter hardness is the so-called "hot collapse," where the filter hardness decreases during smoking. This can occur particularly when, during one of the last puffs of a traditional cigarette, the filter heats up in the presence of moisture. This undesirable effect can also occur with HNB products.

[0015] In addition to maintaining a consistently high filtration hardness during use, the mouthpiece material should also exhibit a predetermined or definable filtration performance. The filtration performance with regard to condensed matter (droplets, particles), also known as condensate or tar, is of interest for both conventional tobacco products and HNB products, as the condensed matter contains a multitude of substances with negative health implications.

[0016] In conventional cigarettes, the filtration performance (along with other factors such as tobacco blend, ventilation, etc.) is selected to adjust the cigarette's "delivery" (the concentration of smoke constituents in the mainstream smoke). In many markets, the "delivery" is legally limited. Below the legal limit, the "delivery" can be adjusted to meet consumer preferences.

[0017] HNB products contain significantly less condensed matter with negative health implications in the aerosol than conventional products. However, since desirable substances such as flavor enhancers and nicotine are also present in the condensate, the objective here is to select the lowest possible filtration efficiency, which, however, must not drop to zero.

[0018] Regarding the target parameter "draw resistance," it should be noted that consumers prefer a certain range of draw resistance when consuming a tobacco product. With conventional cigarettes, the filter (in addition to the "Delivery" setting) serves to adjust the draw resistance.

[0019] However, with HBN products, the contribution of the mouthpiece filter to the draw resistance should generally be as low as possible, since the other components of the HBN device, especially the heated tobacco portion and the device itself, already contribute significantly to the draw resistance. A low draw resistance from the filter (mouthpiece) allows for greater flexibility in the other components of the HBN device, which is desirable.

[0020] However, draft and filtration performance are closely linked. Both can be reduced in several ways, but this often negatively affects other parameters.

[0021] For example, the draft resistance and filtration efficiency can be reduced by shortening the filter length. However, as soon as the filter length becomes smaller than the filter diameter, processing becomes problematic. A shorter filter also results in a shorter cooling path, which is problematic for heat management.

[0022] Alternatively or additionally, the tensile resistance and filtration performance can be reduced by reducing the fiber weight in the filter material per volume fraction and / or the total fiber content. However, this has the disadvantage that the filter hardness decreases and the minimum hardness may no longer be achievable.

[0023] Alternatively or additionally, the tensile resistance and filtration efficiency can be reduced by increasing the filament titer. With a constant filter diameter and a given fiber weight per unit volume, increasing the filament titer reduces the filtration efficiency and tensile resistance, which is desirable for HNB products compared to conventional products. Since, as explained above, the filter hardness hardly depends on the filament titer, the hardness is not negatively affected.

[0024] Regarding the objective parameter "appearance," it should be noted that consumers prefer a mouthpiece with a flat, white, mouth-side cross-sectional surface. However, there are also products that are shaped into a tube at the mouth side.

[0025] Although conventional cigarette filters, which are usually made of cellulose acetate filaments, ensure optimal filtration of smoke constituents, these filter materials are often only suitable to a limited extent for other applications, especially for HNB products or e-cigarettes, since in these applications the filter materials or materials for the mouthpiece have to perform other functions.

[0026] HNB products, as well as conventional smoking products, generally have the disadvantage that the inhaled aerosol is absorbed by the user at a high temperature. This can be unpleasant for the user. Therefore, especially with HNB products, the mouthpiece materials have the task of cooling the aerosol with the lowest possible filtration efficiency.

[0027] However, even with classic cigarettes, especially so-called slim or ultra-slim cigarettes (i.e., cigarettes with a small diameter of, for example, 5.0 mm to 6.5 mm), filter materials and mouthpiece materials must offer reduced filtration performance compared to filter materials for king-size cigarettes, along with increased cooling and improved haptic properties (a firm but not too hard grip). Naturally, less smoke / flavor is produced during combustion than with a king-size cigarette. To avoid further reducing the flavor, a lower filtration performance is desired. If only the amount of filter material is reduced for this purpose, the filter hardness will eventually become insufficient.

[0028] Filters for slim or ultra-slim cigarettes also have significantly higher draw resistance than king-size filters at the same fiber density, which is generally undesirable.

[0029] For both HNB products and slim or ultra-slim cigarettes, it has been proposed to achieve the desired reduced filtration efficiency with regard to condensable components, such as tar, as well as sufficient filter hardness, by increasing the filament titer while maintaining the overall titer. However, this approach has several disadvantages.

[0030] Cellulose 2,5-acetate is widely used today for the production of filter rods for filter elements or cigarette filters. In light of the discussion surrounding smoking and health, it demonstrably possesses outstanding properties regarding specific retention phenomena. For example, a cellulose acetate filter filters out harmful nitrosamines and phenols far more efficiently than condensate and nicotine. Furthermore, smokers rate the taste of the tobacco blend most pleasant when combined with a cellulose acetate filter element. Another significant advantage of a cellulose 2,5-acetate filter element lies in the optical homogeneity of the filter's cut surfaces.

[0031] However, despite their undeniable market dominance, cellulose-2,5-acetate filter elements have some serious disadvantages: tensile resistance and filtration performance are clearly defined for filter rods due to design-related physical requirements.

[0032] The particle filtration or condensation ionization of a typical cellulose-2,5-acetate filter element is a function of filament titer (fiber fineness), filter diameter, tensile resistance and filter length.

[0033] The production of filter elements becomes problematic when a filtration performance of significantly more than 50% is required, as is necessary for the construction of ultra-light cigarettes, with a typical filter diameter of 7.8 mm and a filter length of 21 to 25 mm.

[0034] The same principle applies, metaphorically speaking, to filter elements for slim or ultra-slim cigarettes. Since the smoke flows parallel to the fiber direction in a filter element, such a filter element can only be achieved by significantly reducing the filament titer, which, while maintaining the overall titer, would simultaneously result in a significant increase in draw resistance.

[0035] The total titer and filament titer must therefore be reduced equally, with the consequence that the hardness of the filter element is drastically reduced, especially during the smoking process. This phenomenon is referred to by those skilled in the art as "hot collapse" and is considered fundamentally undesirable. DE 102019135114 A1 describes a filter material for mouthpieces for use with tobacco products or HNB products, based on cellulose acetate filaments that are partially hollow. In further embodiments, these filaments are crimped, cross-linked, and can have a filament titer of 5 to 30 denier and a total titer of 4,000 to 40,000 denier. The specific fiber weight (acetate weight) is preferably in the range of 3 to 4 mg / mm of filter length, and a lower specific fiber weight is discouraged.

[0036] The present invention aims to provide a filter element, particularly for so-called slim or ultra-slim cigarettes, i.e., cigarettes with a small diameter of, for example, 5.0 mm to 6.5 mm, wherein the filter element exhibits sufficient filter hardness despite reduced filtration performance and increased cooling. Furthermore, the filter element should enable an adjustable and, in particular, reduced draw resistance compared to king-size filters.

[0037] This problem is solved according to the invention by a filter element having the features of independent claim 1, wherein advantageous further developments of the filter element according to the invention are specified in the dependent claims.

[0038] Accordingly, the invention relates in particular to a filter element for mouthpieces for use with tobacco products or HNB products, wherein the filter element comprises a filter body made of a tow material. The tow material is formed by a plurality of individual threads of cross-linked and crimped cellulose acetate filaments, wherein the cellulose acetate filaments in particular have a multilobal or polygonal and preferably Y-shaped cross-sectional geometry.

[0039] The filter element according to the invention is characterized in particular by the fact that a specific filament titer is selected for the cellulose acetate filaments of the tow material. Preferably, the filament titer is in a range of less than or equal to 10 denier and greater than or equal to 5 denier.

[0040] Furthermore, a relatively low total titer, preferably a total titer in a range of less than or equal to 10,000 denier and greater than or equal to 5,000 denier, is selected for the tow material of the filter element according to the invention.

[0041] It was surprisingly found that, despite the comparatively low filament titer of less than or equal to 10 denier and the relatively low total titer of less than or equal to 10,000 denier, the occurrence of the completely undesirable hot collapse phenomenon can be effectively avoided even when used in slim or ultra-slim cigarettes if a comparatively low value of less than or equal to 2.5 mg per mm filter element length is chosen for the specific fiber weight of the cellulose filaments of the tow material, i.e., for the so-called acetate weight.

[0042] With specifications regarding the relatively low filament titer, the relatively low total titer, and the relatively low specific fiber weight of the cellulose acetate filaments (acetate weight), a filter element can be realized that achieves the filtration performance required for the construction of slim or ultra-slim cigarettes without significantly increasing draw resistance. These parameters allow for a considerable increase in the performance and application range achievable with the filter element.

[0043] In particular, the cellulose acetate filaments of the Tow material exhibit at least a trilobal, i.e., three-armed star-shaped, cross-sectional form. Such a cross-sectional form is advantageous when the cellulose acetate filaments are required to have the largest possible specific surface area in order to enable high filtration efficiency with simultaneous economical use of raw materials, if desired, for example, in conventional cigarettes.

[0044] Alternatively, a desired large specific surface area can be achieved using a bundle of extremely fine filaments, for example, with a circular cross-section. However, other cross-sectional shapes for the cellulose acetate filaments are also conceivable, such as a multilobal, polygonal, or X-shaped cross-section.

[0045] The tow material of the filter element according to the invention is formed from endless compression-chamber crimped cellulose acetate filaments. A solution of approximately 30% cellulose-2,5-acetate in acetone is forced through spinnerets, the acetone is evaporated in a spinning shaft, a large number of cellulose acetate filaments (5,000 to 10,000) are gathered into a tape, and this tape is then compression-chamber crimped.

[0046] The product is then dried, placed in storage containers and finally pressed into bales weighing between 300 and 600 kg.

[0047] After the Filtertow bales are transported to the filter or cigarette manufacturer, the Filtertow is removed from the bale and processed into filter sticks on a filter stick machine. In this process, the Filtertow is stretched in a drawing unit, coated with an additive to bond the filaments, and then, after the formation of a three-dimensional wick, fed into the format section via an infeed funnel. There, it is compacted transversely, wrapped in paper, and cut to the final length of the filter sticks.

[0048] The additive used to bond the filaments is typically a high-boiling solvent for cellulose acetate, such as glycerol triacetate (triacetin), which briefly dissolves the surface of the filaments after application. Wherever two filaments happen to touch, a solid bond forms after some time, as the excess additive migrates into the fiber surface, causing the previously liquid droplet of cellulose-2,5-acetate solution to solidify within the additive. After a storage period of less than one hour, the aforementioned migration of the hardening agent results in mechanically rigid, three-dimensionally cross-linked filter rods of low packing density, which, due to their hardness, can be easily processed at high speeds on modern cigarette-making machines.

[0049] By selecting a relatively low filament titer, a relatively low total titer and an acetate weight of less than or equal to 2.5 mg per mm of filter element length for the tow material of the filter element according to the invention, a filter element can be realized which achieves a desired filtration performance with respect to condensable components but still a sufficient filter hardness while maintaining the low total titer.

[0050] According to embodiments of the filter element according to the invention, the cellulose acetate filaments of the individual threads of the Tow material are formed at least partially as hollow and / or tubular cellulose acetate filaments.

[0051] Hollow or tubular cellulose acetate filaments are preferably to be understood as cylindrical filaments which, in cross-section, have one or more continuous cavities.

[0052] Such hollow fibers can be at least partially designed as multi-lumen hollow fibers. Compared to solid cellulose acetate filaments, single- or multi-lumen tubular cellulose acetate filaments are significantly more resistant to buckling, thus enabling particularly high filtrona hardness without increased material compaction.

[0053] Because the filter element according to the invention has a filter body which can be based at least partially on cellulose acetate filaments which are at least partially formed as hollow cellulose acetate filaments, a low tensile resistance and a low filtration performance can be achieved, since the filaments of the filter element which are at least partially formed as hollow cellulose acetate filaments have a small external surface area in relation to the total fiber volume.

[0054] In this context, it was surprisingly found that particularly high filtration hardnesses can be achieved with the filter element due to the filaments being formed at least partially as hollow cellulose acetate filaments.

[0055] In fact, it has been found that filter elements which are at least partially made of hollow cellulose acetate filaments (hollow fibers) achieve the desired minimum filtration hardness with a lower fiber weight per unit volume.

[0056] Since the filter element according to the invention is based on cellulose acetate filaments, the filter element according to the invention is designed to form a uniform, white and flat mouth-side end face for a tobacco strand, for example of a cigarette, and furthermore a selective filtration effect on phenols is achievable.

[0057] By using a filter element based on cellulose acetate filaments, it is possible to produce filter rods, especially for cigarettes, which demonstrably exhibit properties with regard to specific retention phenomena that are worth highlighting in the discussion concerning smoking and health.

[0058] A cellulose acetate filter filters out harmful nitrosamines and phenols far more efficiently than condensate and nicotine. Furthermore, smokers find that the flavor of today's common tobacco blends, such as "American Blend," "German Blend," and "Virginia," is most pleasant when combined with a cellulose acetate filter. Another significant advantage of a cellulose acetate filter lies in the optical homogeneity of the filter's cut surfaces.

[0059] In embodiments, the filter element according to the invention is at least partially formed from hollow cellulose acetate filaments, which serve as filling material, allowing the tensile resistance and filtration performance of filter rods made from the material according to the invention to be varied over a wide range.

[0060] In particular, it has been shown that a filter material consisting at least partially of hollow cellulose acetate filaments exhibits improved thermal cooling. It was found that the use of hollow cellulose acetate filaments as a filler material still allows for a very low filtration efficiency, i.e., retention efficiency, for the suspended solids and gases to be removed.

[0061] It is assumed that this effect is achieved because the hollow cellulose acetate filaments alter the surface area or the flow of the gas or air to be purified in such a way that any suspended particles present in the gas or air are hardly retained. Another reason could be that the use of hollow cellulose acetate filaments allows for a different, particularly advantageous surface structure of the filter material.

[0062] The filter element according to the invention further has the advantage that it enables, in particular, adjustable cooling of a heated, particle-laden gas (especially aerosol), so that the temperature of the gas, aerosol, or vapor inhaled by the user of a smoking product or HNB product can be specifically reduced. The desired cooling effect can be adapted to the specific application by varying the proportion of hollow cellulose acetate filaments in the filter and / or filling material.

[0063] It is also important to mention that the hollow cellulose acetate filaments (= hollow fibers) in the filter element according to the invention are essentially surrounded by the flow of air rather than being flowed through. From geometric considerations, it is evident that the fiber-to-fiber distances are significantly larger than the lumen (hollow portion) of the hollow fiber. The viscosity of the aerosol (essentially air) then ensures that the path of least resistance is chosen (i.e., it flows between the filaments and not through each individual filament).

[0064] In other words, in the embodiment of the filter element according to the invention, the filtration-effective surface area is by no means maximized, since the hollow cellulose acetate filaments in the Tow material are not permeated by flow.

[0065] In particular, the hollow cellulose acetate filaments can thus have kinks that close the lumen of the hollow cellulose acetate filaments without this having any influence on the performance of the filter and / or filling material according to the invention with regard to the set target parameters.

[0066] In this context, it is particularly important to mention that the hollow cellulose acetate filaments, designed as hollow fibers, do not have to be completely hollow, but can also be partially closed by kinks. They can also deviate from a perfect circular shape.

[0067] In embodiments of the invention, the hollow cellulose acetate filaments of the Tow material serve both as a support material and as a cooling material. By simultaneously using the hollow cellulose acetate filaments as a support material, particularly compact filter elements can be realized, eliminating the need to increase the dimensions of the smoking product.

[0068] The term "Filtrona hardness" used herein refers to the filter hardness determined according to the Filtrona principle. This principle determines the filter hardness by pressing a cylindrical rod with a diameter of 12 mm vertically, with its flat end, against a horizontally positioned filter rod using a load of 300 g. The ratio of the compressed diameter to the initial diameter determined by the first contact yields the percentage value of the Filtrona hardness.

[0069] Filter element or filter rod hardness is an important target criterion, especially for cigarette filters. It is usually specified as the filtrona hardness. It is important to note that the filtrona hardness is measured only on the filter element itself, not on the underlying filter (raw) material, i.e., the tow material. The filtrona hardness of a filter element is primarily influenced by the amount of triacetin that is sprayed onto the filter element.

[0070] The minimum limit for the filter hardness is approximately 88% and is based on market requirements. The filter hardness of the filter element can preferably be set to approximately 88% to 95%, and in particular approximately 90% to 93%.

[0071] According to preferred embodiments of the filter element according to the invention, the filter body is designed in particular as a filter rod and preferably has a diameter between about 6 mm and about 4 mm and in particular a diameter between about 5.5 mm and about 5.0 mm and preferably a diameter of about 5.35 mm, wherein the filter body is at least partially covered with a paper material or a paper-like material.

[0072] In this design, the filtration hardness of the filter element should preferably be greater than 85% and especially greater than 90%.

[0073] For a given filter element diameter, the filtrona hardness is determined in particular by the acetate weight, whereby the filament titer of the cellulose acetate filaments of the Tow material has only a minor influence on the filtrona hardness.

[0074] In embodiments of the filter element according to the invention, it is provided that the filter body has an acetate weight which is a maximum of 2.5 mg / mm filter element length.

[0075] The filtration hardness of the filter element can also be achieved by using a stronger filter wrapping paper or a stronger tipping paper.

[0076] Tipping paper is a paper used either to connect multiple filter elements together or to connect a single filter element to a strand of tobacco. However, increasing the filter element's hardness by using a thicker filter wrapping paper or a thicker tipping paper has economic disadvantages, as this approach is expected to result in higher costs.

[0077] Related to the filter element's hardness is the so-called "hot collapse," whereby the filter element's hardness decreases during use, i.e., when used with tobacco products or HNB products. This phenomenon can occur particularly when, during one of the last puffs of a traditional cigarette, the filter element heats up in the presence of moisture. However, this undesirable effect can also occur with HNB products.

[0078] In this context, it has been shown that the degree of decrease in filtrona hardness due to the "hot collapse" phenomenon can be significantly reduced if a tow material with the aforementioned low filament titer, the aforementioned low total titer and the low acetate weight is used as the starting material of the filter element according to the invention.

[0079] The tow material of the filter body of the filter element according to the invention preferably has a mass-related specific surface area in the range between 0.3 m² / g and 0.025 m² / g, and particularly of less than 0.15 m² / g. This allows the tensile resistance and filtration performance of the filter element according to the invention to be reduced without reducing the length of the filter element. Thus, relatively long filter elements can be realized, enabling a correspondingly long cooling section, which is advantageous for the thermal management, especially when the filter element is used with HNB products.

[0080] In addition, by setting the mass-related specific surface area of ​​the tow material to a value of, in particular, less than 0.15 m² / g according to the invention, the tensile resistance and the filtration performance of the filter element can be reduced without reducing the fiber weight in the filter element per volume fraction and / or without reducing the total titer of the tow material. This has the advantage that there is no decrease in the filter element hardness due to a reduction in the fiber weight in the filter element material per volume fraction and / or due to a reduction in the total titer.

[0081] The cellulose acetate filaments of the tow material used as the starting material for the production of the filter element according to the invention are, in particular, cellulose 2,5-acetate, cellulose butyrate, cellulose acetobutyrate, cellulose acetopropionate, and / or cellulose propionate filaments. Preferably, the cellulose acetate filaments have a degree of substitution of about 1.5 to 3.0, more preferably about 2.2 to 2.6.

[0082] The plasticizers preferably used for the plasticization of the cellulose acetate fibers and applied to the fibers can be selected, for example, from the following groups: glycerol esters (especially glycerol triacetate), ethylene and propylene carbonate, citric acid esters (especially acetyl, triethyl citrate), glycose esters or diethylene glycol dibenzoate.

[0083] The amount of plasticizing agent and / or water-soluble adhesive required is well known to those skilled in this field. Generally, the plasticizer and / or adhesive content is approximately 1 to 14 percent by weight; however, in special cases, the plasticizer content can easily exceed this range.

[0084] Water-soluble adhesives, preferably present on the surface of the cellulose acetate filaments, can include in particular high-boiling solvents such as polyalkylene oxide, water-soluble esters or ethers, starch, starch derivatives, p-polyvinyl alcohols, polyvinyl ethers, p-polyvinyl acetates and / or polysaccharides, water-soluble polyamides and polyacrylates, which are applied to the individual threads of the tow material or to the tow material itself.

[0085] In particular, it was recognized that the residual crimp (RS) of the tow material of the filter body and the density ( r The residual ripple density (A) of the filter body has a decisive influence on the performance of the filter element. Preferably, the residual ripple density value A is at least 0.016 mg / mm² with: A = ρ 2 ⋅ RS .

[0086] In particular, the residual crimp (RS) of the tow material of the filter body should not exceed the value of 3.0 and especially the value of 2.75, wherein the residual crimp (RS) of the tow material is preferably between about 1.5 and about 2.75 and especially between 1.9 and 2.5.

[0087] Residual crimp is defined as the ratio of the length of the end-crimped cellulose acetate filaments to the filter element length. Residual crimp is a characteristic feature of a given filter element.

[0088] It was surprisingly found that with a relatively low total titer of the tow material of the filter body, a higher residual crimp value is required to maintain the necessary filter hardness, while the acetate weight remains constant.

[0089] According to a further aspect of the present invention, it is important to specify a tow material for the manufacture of a filter element for mouthpieces for use with smoking products or HNB products, wherein the tow material is optimized such that the filter elements manufactured from the tow material have the most uniform performance possible, particularly with regard to filtration performance and filter hardness.

[0090] In this context, it was determined that it is particularly important that the cellulose acetate filaments of the Tow material have a uniform filament titer, which is either predetermined or definable. This uniform filament titer is specifically in the range between 5 and 10 denier.

[0091] To achieve a uniform performance of the filter element made from the tow material, particularly with regard to filtration performance and filter hardness, the coefficient of variation of the uniform filament titer should be at most 0.1 and preferably at most 0.05 to at most 0.01.

[0092] The coefficient of variation of the uniform filament titer, which can also be called the coefficient of deviation, is a statistical parameter and describes - unlike the variance - a relative measure of dispersion, i.e. it does not depend on the unit of measurement of the statistical variable or random variable.

[0093] In other words, during the production of the tow material, care is taken to ensure that the individual filaments produced by the respective spinnerets of the spinning machine used have a uniform filament titer.

[0094] In practice, this is achieved by assigning each spinneret its own, in particular frequency-controlled, spinning pump to ensure that the spinning liquid (solution of approx. 30% cellulose-2,5-acetate in acetone) is supplied to each spinneret of the spinning machine in such a way that a uniform nozzle pressure and a uniform amount of spinning liquid delivered per unit of time from each spinneret can be achieved.

[0095] This simple yet effective method makes it possible to achieve a uniform filament titer, especially one that is predetermined or definable.

[0096] Alternatively or additionally, it is preferred that the individual threads of the tow material formed from the cellulose acetate filaments have a predetermined or definable and preferably uniform total titer of at least 5,000 denier and at most 10,000 denier, wherein the coefficient of variation of the uniform total titer is preferably at most 0.1 and in particular at most 0.05 to at most 0.005. The coefficient of variation is determined in particular by multiple measurements along the length of the tow.

[0097] This easily implemented measure effectively avoids fluctuating qualities in the production of the filter element according to the invention, which is particularly unacceptable in the market for slim and ultra-slim filters and would therefore lead to productivity losses in the production of the filter elements.

[0098] The advantages associated with the invention are therefore manifold. In particular, it enables the realization of slim and ultra-slim filter elements, effectively preventing the occurrence of the hot collapse phenomenon, even if the tow material of the filter body has a relatively low total titer and a relatively low filament titer.

Claims

1. A filter element for mouthpieces for use with smoking products or HNB products, wherein the filter element has a filter body made from a tow material, whereby the tow material is formed by a plurality of monofilaments of crosslinked and crimped cellulose acetate filaments, whereby the cellulose acetate filaments in particular exhibit a multilobal or polygonal and preferably Y-shaped cross-sectional geometry, wherein: - the cellulose acetate filaments of the tow material exhibit a uniform filament titer, which in particular is predefined or definable, in a range of from less than or equal to 10 denier (11.1 dtex) and greater than or equal to 5 denier (5.5 dtex); - the tow material has a total titer in a range of from less than or equal to 10000 denier (11.1 kdtex) and greater than or equal to 5000 denier (5555.5 dtex); and - the specific fiber weight of the cellulose acetate filaments of the tow material is less than or equal to 2.5 mg per mm of filter element length and greater than or equal to 1.0 mg per mm of filter element length.

2. The filter element according to claim 1, wherein a coefficient of variation of the uniform total titer is at most 0.1 and preferably a maximum of 0.05 to a maximum 0.005.

3. The filter element according to claim 1 or 2, wherein a coefficient of variation of the uniform filament titer is at most 0.1 and preferably a maximum of 0.05 to a maximum 0.01.

4. The filter element according to one of claims 1 to 3, wherein the filter body is in particular realized as a filter rod and preferably with a diameter of between approximately 6 mm and approximately 4 mm and particularly a diameter between approximately 5.5 mm and approximately 5.0 mm and preferably a diameter of approximately 5.35 mm, wherein at least part of the filter body is wrapped in a paper or paper-like material.

5. The filter element according to claim 4, wherein the filter body with the paper or paper-like wrapping has a compression depth of less than 0.90 mm and in particular less than 0.85 mm when the face end of a cylindrical test piece having a mass of 300 g and a diameter of 12 mm is seated on the filter body perpendicular to the filter body axis, or wherein the filter body without the paper or paper-like wrapping has a compression depth of less than 0.90 mm and in particular less than 0.85 mm when the face end of a cylindrical test piece having a mass of 300 g and a diameter of 12 mm is seated on the filter body perpendicular to the filter body axis.

6. The filter element according to one of claims 1 to 5, wherein at least part of the cellulose acetate filaments of the tow material's monofilaments is at least partially formed as hollow and / or tubular cellulose acetate filaments.

7. The filter element according to one of claims 1 to 6, wherein the filter body hardness amounts to at least 80% Filtrona hardness and preferably at least approximately 86% Filtrona hardness.

8. The filter element according to one of claims 1 to 7, wherein the filter body contains a plasticizer having a plasticizer content of between approximately 2% and approximately 15%, and preferably between approximately 4% and approximately 10%, whereby the plasticizer in particular comprises triacetin, triethylene glycol diacetate and / or citric acid ethyl ester.

9. The filter element according to one of claims 1 to 8, wherein the tow material of the filter body exhibits a residual crimp (RS) and a density (ρ), whereby a residual crimp-related density value A amounts to at least 0.016 mg2 / mm6 with: A = ρ 2 ⋅ RS10. The filter element according to one of claims 1 to 9 and in particular claim 9, wherein the residual crimp (RS) of the filter body's tow material does not exceed the value of 3.0, whereby the residual crimp (RS) of the filter body's tow material is preferably between approximately 1.5 and approximately 2.75 and in particular between 1.9 and 2.5.

11. The filter element according to one of claims 1 to 10, wherein the cellulose acetate filaments of the tow material have a tensile strength of at least 2.6 N / kden.

12. A mouthpiece for use with smoking products or HNB products, wherein the mouthpiece comprises a filter element according to one of claims 1 to 11.

13. The mouthpiece according to claim 12, wherein a particularly capsule-shaped or capsule-like flavor release element is furthermore incorporated into the filter element.

14. A cigarette filter or cigarette filter element comprising a filter element according to one of claims 1 to 11.

15. A cigarette filter or cigarette filter element according to claim 14, wherein a particularly capsule-shaped or capsule-like flavor release element is furthermore incorporated into the filter element.

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