Mouthpiece filter elements, mouthpieces for use in smoking products or HNB products, and cigarette filters

Abstract

To identify filter elements that exhibit sufficient filter hardness despite reduced filtering performance and increased cooling, especially for so-called slim or ultra-slim cigarettes. [Solution] A filter element for a mouthpiece for use in a smoking product or HNB product, the filter element having a filter body made of a tow material, the tow material being formed by a plurality of monofilaments of crosslinked and crimped cellulose acetate filaments, the cellulose acetate filaments exhibiting a cross-sectional shape, in particular a multilobal or polygonal, preferably Y-shaped, shape, in which: - the cellulose acetate filaments of the tow material exhibit a uniform filament titer, in particular a predefined or predefinable value, in the range of 10 denier (11.1 dtex) or less and 5 denier (5.5 dtex) or more; - the tow material has a total titer in the range of 10,000 denier (11.1 kdtex) or less and t5,000 denier (5555.5 dtex) or more; and - the specific fiber weight of the cellulose acetate filaments of the tow material is 2.5 mg or less per mm of filter element length and 1.0 mg or more per mm of filter element length.

Description

[Technical Field]

[0001] The present invention relates to a tipping filter element for use with a smoking product or HNB product, and the use of such a filter element in a smoking product tipping or cigarette filter or tipping for an HNB product. [Background technology]

[0002] Smoking products within the meaning of the present invention relate to traditional tobacco products, in particular cigarettes, but also to pipe products 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, the tipping tip for a smoking product can have different functions. For example, the tipping tip can function on the one hand as a filter device that extracts harmful components from the tobacco smoke stream, such as condensed matter, especially tar, as well as particulate matter entrained in the smoke stream. This filtering function is particularly used in conventional tobacco applications. The corresponding tipping tip can thereby be formed as an integral part of the cigarette or cigarillo, thus forming a "support" on the cigarette / cigarillo.

[0004] Another type of tipping example relates to replaceable devices, such as replaceable filter elements that can be removed after use. Such tipspings are housed in a suitable holder, for example a cigarette holder or a pipe tipping.

[0005] One tipping part formed as an integral part of a cigarette is a cigarette filter. Cigarette filters are intended to reduce the proportion of harmful substances, such as condensate and gases, in cigarette smoke. In addition, filters make the smoke smoother or more palatable for most smokers. In conventional filter cigarettes, the filter is surrounded by a filter wrap and connected to the tobacco rod via so-called tipping paper, and most industrially manufactured cigarettes are equipped with a filter.

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

[0007] The present invention does not only relate to filter materials for the above-mentioned conventional tobacco applications, but also in particular to filter materials and / or filter elements for mouthpieces used in smoking products, these filter elements in particular having other functions than just a filtering function.

[0008] Therefore, the materials required to form the tipping for a smoking product must be compatible, and in particular must be compatible, with the physical properties (temperature, flow profile, etc.) and chemical composition of smoke. Both conventional cigarette filters and HNB products have several target parameters that must be adjusted or met, respectively, by appropriate selection and configuration of the tipping material. This relates in particular to the following target parameters, which are briefly discussed below: ·Suction resistance Filtering performance Filter rod hardness / filtrona hardness Visual appearance

[0009] Filter rod hardness is an important target criterion for cigarette filters. It is usually indicated as the so-called Filtrona hardness. Fitrona hardness is determined by pressing the flattened front end of a cylindrical rod with a diameter of 12 mm vertically against a horizontally positioned filter rod with a load of 300 g. The ratio of the compressed diameter to the initial diameter previously determined at first contact yields the Filtrona hardness percentage.

[0010] It should be emphasized that Filtrona firmness is measured only in the filter, and not in the parent (raw) filter material. Filtrona firmness is particularly affected by triacetin, which is sprayed onto all cigarette filters.

[0011] The minimum limit of Filtrona hardness is about 88%, which is set in accordance with market requirements. Therefore, the Filtrona hardness of cigarette filters can be preferably set to about 88% to 95%, particularly about 90% to 93%.

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

[0013] Sometimes, a higher Filtrona hardness can be achieved by using stronger filter wrap paper or stronger tipping paper. Tipping paper is the paper that bonds multiple filter elements together or the paper that bonds the filter element to the tobacco rod. However, increasing Filtrona hardness by using stronger filter wrap paper or stronger tipping paper has economic disadvantages, as this approach can be expected to be more expensive.

[0014] Filtrona hardness is accompanied by a so-called "hot collapse," a decrease in filter hardness during smoking. This can occur particularly in conventional cigarettes when the filter is heated in the presence of moisture during one of the final puffs. This undesirable effect can also occur with HNB products.

[0015] In addition to a Filtrona hardness that is as constant and high as possible during use of the smoking product, the tipping material must also exhibit a predetermined or definable filtering performance. The filtering performance with respect to condensed matter (droplets, particles), also called condensate or tar, is of interest for conventional tobacco products and HNB products, because condensed matter contains several substances that have unhealthy effects.

[0016] In conventional products, filtration performance (along with other influencing factors such as tobacco blend, breathability, etc.) is selected to adjust the "delivery" of a cigarette (the level of smoke constituents in mainstream smoke). In many markets, legal regulations dictate an upper limit for "delivery." Below the legal limit, "delivery" can be tailored to consumer preferences.

[0017] In HNB products, the aerosol contains much less condensate, which has negative health effects, than in conventional products. However, since more desirable materials such as flavors and nicotine are also present in the condensate, the objective here is to select the lowest possible filtering performance without reducing it to zero.

[0018] With respect to the target parameter of "resistance to draw," it is noteworthy that consumers prefer a range of resistance to draw when using tobacco products. In traditional cigarettes, the filter (in addition to adjusting "delivery") serves to adjust the resistance to draw of the cigarette.

[0019] However, in HNB products, the resistance to draw provided by the mouth-end filter (tip) should tend to be as low as possible, since other components of the HBN device, particularly the heated portion of the tobacco and the device, already provide a high contribution to resistance to draw. A low filter (tip) resistance to draw allows some flexibility with respect to other components of the HBN device, which is desirable.

[0020] However, resistance to draw and filtering performance are closely related: both can be reduced in several ways, often with a negative impact on other parameters.

[0021] For example, the resistance to suction and filtering performance can be reduced by shortening the length of the filter. However, when the filter length is smaller than the filter diameter, processability becomes an issue. A shorter filter also results in a shorter cooling section, which is a problem in terms of heat balance. Alternatively or additionally, the resistance to suction and filtering performance can be reduced by reducing the fiber weight in the filter material per volume content and / or total weight. However, this has the drawback of reducing the Filtrona hardness, and the minimum hardness may no longer be achieved.

[0022] Alternatively or additionally, the resistance to suction and filtering performance can be reduced by increasing the filament strength. At a constant filter diameter and a fixed fiber weight per volume unit, the filtering performance and resistance to suction decrease with increasing filament strength, which is desirable for HNB products compared to conventional products. As mentioned above, Filtrona hardness is only slightly dependent on filament strength, so hardness is not adversely affected either.

[0023] Regarding the target parameter of "visual appearance," it is noteworthy that consumers prefer mouthpieces that have a flat, white cross-section at the mouth end. However, some products are formed into a tube at the mouth end.

[0024] Although conventional cigarette filters, which are usually composed of cellulose acetate filaments, ensure optimal filtering of constituents in the smoke, these filter materials can often only be used to a limited extent in other applications, especially in the case of HNB products or electronic cigarettes, because in these applications the filter material or the respective tipping material must perform other functions.

[0025] HNB products and conventional smoking products generally have the disadvantage that users ingest inhaled aerosol at a high temperature, which can be uncomfortable for users. In particular, with HNB products, the tipping material has the challenge of cooling the aerosol with the lowest possible filtering performance.

[0026] However, even in the case of conventional cigarettes, particularly so-called slim or ultra-slim cigarettes, i.e., small-diameter cigarettes, for example, 5.0 mm to 6.5 mm, the filter / tip material must provide reduced filtering performance, increased cooling properties, and improved tactile properties (firm, but not too firm when gripped) compared to filter materials for king-size cigarettes. Naturally, the smoke / flavor during combustion is less than that of king-size cigarettes. A low filtering performance is required to avoid further reduction in flavor. Reducing the amount of filter material alone to its limit ultimately results in unsatisfactory filter hardness.

[0027] At the same fiber density, filters for slim or ultra-slim cigarettes also have a significantly higher resistance to draw than king-size filters, which is generally undesirable.

[0028] For both HNB products and slim or ultra-slim cigarettes, it has been proposed to increase the filament titer while maintaining the total titer in order to achieve the desired reduced filtering performance with respect to condensable components such as tar, as well as sufficient filter hardness. However, this approach has various drawbacks.

[0029] Cellulose 2,5-acetate is widely used today to manufacture filter elements and filter rods for cigarette filters. From the standpoint of smoking and health, it has clearly superior properties with regard to specific retention phenomena. Filters made from cellulose acetate filter harmful nitrosamines and phenols much more efficiently than aggregates and nicotine. Furthermore, smokers rate the taste of tobacco blends combined with cellulose acetate filter elements as the most palatable. An additional advantage of filter elements made from cellulose 2,5-acetate is the visual uniformity of the filter's cut surface.

[0030] However, despite their significant market dominance, cellulose-2,5-acetate filter elements have some significant drawbacks: the filter rods have well-defined resistance to suction and filtering performance due to structural and physical constraints.

[0031] The particle filtration or even condensate retention of a typical cellulose-2,5-acetate filter element is a function of filament titer (fiber fineness), filter diameter, resistance to suction and filter length.

[0032] 7. Assuming a typical filter diameter of 8 mm and a filter length of 21-25 mm, this becomes problematic when a filter performance significantly greater than 50% is required during the manufacture of the filter element, as is required when designing ultra-light cigarettes.

[0033] The same applies analogously to filter elements for slim or ultra-slim cigarettes: since the smoke in the filter element flows parallel to the fiber direction, such filter elements can only be obtained by significantly reducing the filament titer, which at the same time results in a significant increase in the resistance to draw, while the total titer remains unchanged.

[0034] Therefore, the total titer and filament titer must be correspondingly reduced, resulting in a dramatic decrease in the stiffness of the filter element, especially during smoking, a phenomenon known by those skilled in the art as "hot collapse" and generally considered undesirable. Summary of the Invention [Problem to be solved by the invention]

[0035] The present invention is based on the problem of specifying a filter element, in particular for so-called slim or ultra-slim cigarettes, i.e. cigarettes with a small diameter, for example between 5.0 mm and 6.5 mm, which exhibits a sufficient filter hardness despite a reduced filtering performance and increased cooling. The filter element should furthermore be adjustable and be able to achieve a reduced resistance to draw, in particular compared to king-size filters. [Means for solving the problem]

[0036] The present invention solves this problem with a filter element having the features of independent claim 1, advantageous further developments of the inventive filter element being specified in the dependent claims. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention therefore particularly relates to a mouthpiece filter element for use with a smoking or HNB product, the filter element having a filter body made from a tow material formed by a plurality of monofilaments of cross-linked and crimped cellulose acetate filaments, the cellulose acetate filaments in particular presenting a multilobal or polygonal, preferably Y-shaped, cross-sectional shape.

[0038] The filter element according to the invention is characterized in particular by a particular filament strength selected for the cellulose acetate filaments of the tow material, which preferably ranges from less than 10 denier to more than 5 denier.

[0039] Additionally, a relatively low total strength is selected for the tow material of the filter element of the present invention, preferably in the range of less than 10,000 denier and more than 5,000 denier.

[0040] Surprisingly, it has now been found that, despite a relatively low filament strength of 10 denier or less and a relatively low total strength of 10,000 denier or less, the completely undesirable hot collapse phenomenon can be effectively prevented even in the case of slim or ultra-slim type cigarettes, when a relatively low value for the specific fiber weight of the cellulose filaments of the tow material, i.e., the so-called specific acetate weight, is selected of 2.5 mg or less per mm of filter element length.

[0041] By using specifications for a relatively low filament titer, a relatively low total titer, and a relatively low specific fiber weight (acetate weight) of the cellulose acetate filaments, it is possible to achieve a filter element that achieves the filter performance required in the engineering of slim or ultra-slim type cigarettes without significantly increasing the resistance to draw. These parameters make it possible to significantly increase the performance and range of applications achievable with the filter element.

[0042] In particular, the cellulose acetate filaments of the tow material exhibit at least a partially trilobal, i.e., three-armed, star-shaped cross-sectional shape, which is well suited for allowing the cellulose acetate filaments to have the largest possible specific surface area, thereby enabling high filtration capacity, which may be desirable along with economical use of raw materials, as is the case, for example, with conventional cigarettes.

[0043] Alternatively, bundles of very fine filaments, for example of circular cross section, can be used to obtain the desired large specific surface area, although other cross-sectional shapes for the cellulose acetate filaments are also contemplated, for example multilobal, polygonal or X-shaped cross-sections.

[0044] The tow material for the filter element of the present invention is formed from continuous stuffer box crimped cellulose acetate filaments by passing an approximately 30% acetone solution of cellulose 2,5-acetate through a spinneret, evaporating the acetone in the spinning chamber, and collecting multiple cellulose acetate filaments (5,000-10,000) into a strip and crimping it in a stuffer box.

[0045] The product is then dried, filled into storage containers and finally compressed into bales weighing between 300 and 600 kg.

[0046] After the filter tow bales are transported to the filter or cigarette manufacturer, the filter tow is removed from the bale and processed into filter rods on a filter rod machine, whereby the filter tow is drawn in a drawing device with additives that help bind the filaments to form a three-dimensional roving, which is then introduced through an inlet funnel into a forming unit where it is cross-axially compressed, wound into paper, and cut to the final length of the filter element.

[0047] The additives applied to bond the filaments are usually high-boiling solvents for cellulose acetate, such as glycerol triacetate (triacetin), which solubilize the surface of the filaments for a short time after application. When two filaments come into contact, excess additive migrates to the fiber surface, and over time, permanent bonding points form, and the cellulose 2,5-acetate droplets solidify within the additive. This stiffening agent migration results in a mechanically strong, low-packing, three-dimensionally crosslinked filter rod after a storage period of less than one hour, which, due to its hardness, can be easily processed at high speeds on modern cigarette machines.

[0048] For the tow material of the filter element according to the present invention, selecting a relatively low filament titer, a relatively low total titer, and an acetate weight of 2.5 mg or less per mm of filter element length makes it possible to achieve a filter element that achieves the desired filtering performance with respect to condensable components, yet still has sufficient filter hardness while maintaining a low total titer.

[0049] According to an embodiment of the filter element of the present invention, the monofilament cellulose acetate filaments of the tow material are at least partially formed as hollow and / or tubular cellulose acetate filaments.

[0050] What is particularly understood by hollow / tubular cellulose acetate filaments are preferably cylindrical filaments which, when viewed in cross section, exhibit one or more continuous cavities.

[0051] Such hollow fibers may be designed, at least in part, as multi-lumen hollow fibers. Compared to "solid" cellulose acetate filaments, single-lumen or multi-lumen tubular cellulose acetate filaments are significantly more resistant to kinking, thereby allowing particularly high Filtrona stiffness to be achieved without increased material compression.

[0052] Because the filter element of the present invention comprises a filter body that may be based at least in part on cellulose acetate filaments that are at least partially formed as hollow cellulose acetate filaments, low resistance to draw and low filtering performance can be achieved because the filaments of the filter element that are at least partially formed as hollow cellulose acetate filaments have a low external surface area relative to the total fiber volume.

[0053] In this connection, it has surprisingly been found that a particularly high Filtrona hardness can be achieved with the present filter element due to the fact that the filaments are formed as partly hollow cellulose acetate filaments.

[0054] In fact, it has been found that filter elements formed at least in part from hollow cellulose acetate filaments (hollow fibers) achieve the desired minimum Filtrona stiffness at a relatively low fiber weight per unit volume.

[0055] Because the filter element of the present invention is based on cellulose acetate filaments, the filter element of the present invention is designed to form a uniform, white, and smooth mouth-side front end, for example, with respect to the tobacco rod of a cigarette, and can further achieve selective phenol filtration effects.

[0056] On the one hand, the use of filter elements based on cellulose acetate filaments makes it possible to produce filter rods, particularly for cigarettes, which exhibit clearly superior properties with regard to certain retention phenomena from the smoking and health standpoint.

[0057] Cellulose acetate filters filter harmful nitrosamines and phenols much more efficiently than aggregates and nicotine. Furthermore, smokers rate today's popular tobacco blends, such as "American Blend," "German Blend," and "Virginia," paired with cellulose acetate filter rods as tasting the best. A further advantage of cellulose acetate filter rods is the visual uniformity of the filter's cut surface.

[0058] With the filter elements of the present invention formed at least in part from hollow cellulose acetate filaments that function as a filler material according to embodiments, filter rods made from the materials of the present invention can have a wide variety of suction resistance and filtering performance.

[0059] In particular, it has been shown that filter materials consisting at least in part of hollow cellulose acetate filaments exhibit improved thermal cooling effects. It has been determined that the use of hollow cellulose acetate filaments as a filler material still achieves a very low filtering effect, i.e., a retention effect on suspended solids and gases to be removed.

[0060] It is speculated that this effect is achieved by the hollow cellulose acetate filaments changing the surface area or flow rate of the gas or air being purified in such a way that only small amounts of potentially suspended matter in the gas / air are retained. Another reason may be that the use of hollow cellulose acetate filaments can achieve a different, particularly advantageous, filter material surface structure.

[0061] The filter elements of the present invention further have the advantage of allowing for particularly variable cooling of heated particle-containing gases (especially aerosols), thereby allowing for selective reduction in the temperature of the gases, aerosols, or water vapor taken in by the user of the smoking or HNB product. By varying the proportion of hollow cellulose acetate filaments in the filter and / or filler material, the desired cooling effect can be specifically tailored to the application.

[0062] It is further important to note that in the filter elements of the present invention, flow is essentially around the hollow cellulose acetate filaments (hollow fibers), and less through them. Geometric considerations reveal that the interfiber distance is significantly greater than the lumen of the hollow fibers. In this case, the viscosity of the aerosol (essentially air) creates the path of least resistance to be obtained (i.e., flow between the filaments, not through each individual filament).

[0063] In other words, in embodiments of the filter element of the present invention, the effective filtration surface is never maximized because there is no flow through the hollow cellulose acetate filaments in the tow material.

[0064] Thus, in particular, hollow cellulose acetate filaments can have kinks that obstruct the lumen of the hollow cellulose acetate filaments without affecting the performance of the filter and / or filler material of the present invention with respect to set target parameters.

[0065] Of particular note in this context is that hollow cellulose acetate filaments realized as hollow fibers need not be continuously hollow, but rather may be partially closed by kinks. They may deviate from an ideal circular shape.

[0066] An embodiment of the present invention provides that the hollow cellulose acetate filaments of the tow material function on the one hand as a support material and on the other hand as a cooling material, whereby a particularly compact filter element can be realized, thereby avoiding the need to increase the dimensions of the smoking article.

[0067] As used herein, the term "filtrona hardness" refers to the filter hardness determined according to the Filtrona principle. Under this principle, filter hardness is determined by vertically pressing the flat front end of a cylindrical rod with a diameter of 12 mm onto a horizontally placed filter rod with a load of 300 g. The ratio of the compressed diameter to the initial diameter previously determined at the first contact yields the Filtrona hardness percentage.

[0068] The hardness of the filter element or filter rod, respectively, is an important target criterion, particularly for cigarette filters. This is typically indicated as the so-called Filtrona hardness. It should be emphasized that the Filtrona hardness is measured only on the filter element, but not on the original (raw) filter material, and therefore not on the tow material. The Filtrona hardness of the filter element is particularly influenced by the amount of triacetin that can be or is sprayed onto the filter element.

[0069] The minimum Filtrona hardness is about 88%, which is set according to market requirements. Therefore, the Filtrona hardness of the filter element can be preferably set to about 88% to 95%, particularly about 90% to 93%.

[0070] A preferred embodiment of the filter element of the present invention provides a filter body, particularly as a filter rod, preferably having a diameter of about 6 mm to about 4 mm, particularly about 5.5 mm to about 5.0 mm, preferably about 5.35 mm, at least a portion of which is wrapped in paper or a paper-like material.

[0071] The Filtrona hardness of the filter element is preferably greater than 85%, especially greater than 90%, in this embodiment.

[0072] Filtrona firmness is determined specifically by the acetate weight for a given filter element diameter, and the filament strength of the cellulose acetate filaments of the tow material has only a small effect on Filtrona firmness.

[0073] In the construction of the filter element of the present invention, the filter body is provided with an acetate weight of up to 2.5 mg per mm of filter element length.

[0074] The Filtrona hardness of the filter element can also be achieved with stronger filter wrap paper or stronger tipping paper.

[0075] Tipping paper is the paper by which multiple filter elements are bonded together or by which a filter element is bonded to a tobacco rod. However, increasing the Filtrona stiffness of a filter element by using stronger filter wrap paper or stronger tipping paper has economic disadvantages, as higher costs can be expected with this approach.

[0076] The Filtrona hardness of the filter element is subject to so-called "hot collapse," which means that the filter hardness decreases as the filter element is used, i.e., as the filter element is smoked or used with an HNB product. This phenomenon can occur particularly in traditional cigarettes when the filter element is heated in the presence of moisture during one of the final puffs, but this undesirable effect can also occur in HNB products.

[0077] In this context, it is shown that the degree to which Filtrona hardness decreases due to the "hot collapse" phenomenon can be significantly reduced when tow materials having the described low filament titer, the described low total titer and the low acetate weight are used as the substrate for the filter elements of the present invention.

[0078] The tow material of the filter body of the filter element of the present invention is preferably 0.3 mm 2 / g~0.025m 2 / g range, especially 0.15m 2 / g。 Therefore, the resistance to draw and filtering performance of the filter element of the present invention can be reduced without a reduction in the length of the filter element. Therefore, relatively long filter elements can be realized, allowing for a correspondingly long cooling section, which is advantageous in terms of heat balance, especially when the filter element is used with HNB products.

[0079] In addition, especially 0.15m 2 The inventive specification of the mass specific surface area of ​​the tow material at a value less than 1 / g allows for a reduction in the resistance to draw and filtering performance of the filter element without reducing the fiber weight in the filter element per volume fraction and / or reducing the total titer of the tow material, which has the advantage that there is no reduction in the Filtrona hardness of the filter element due to the reduction in the fiber weight in the filter element material per volume fraction and / or due to the reduction in the total titer.

[0080] The cellulose acetate filaments of the tow material serving as the base product for producing the filter element of the present invention are in particular cellulose 2,5-acetate, cellulose butyrate, cellulose acetate butyrate, cellulose acetate propionate and / or cellulose propionate filaments. The cellulose acetate filaments preferably have a degree of substitution of about 1.5 to 3.0, preferably about 2.2 to 2.6.

[0081] For example, plasticizers preferably used for plasticizing cellulose acetate fibers and applied to the fibers can be selected from the following group: glycerol esters (especially glycerol triacetate), ethylene and propylene carbonates, citric acid esters (especially acetyl citrate, triethyl citrate), glucose esters or diethylene glycol dibenzoate.

[0082] Those skilled in the art are familiar with the amount of plasticizer and / or water-soluble binder used. Generally, there is about 1-14% by weight of plasticizer and / or binder content, although in special cases the plasticizer content can easily exceed this range.

[0083] The water-soluble binder preferably present on the surface of the cellulose acetate filaments may in particular be a high-boiling solvent applied to the monofilaments or to the tow material, such as polyalkylene oxides, water-soluble esters or ethers, starch, starch derivatives, p-polyvinyl alcohol, polyvinyl ethers, p-polyvinyl acetate and / or polysaccharides, water-soluble polyamides and polyacrylates.

[0084] It was particularly recognized in this case that the residual crimp (RS) of the tow material of the filter body and the density (ρ) of the filter body also have a significant effect on the performance of the filter element. Therefore, the density value A related to the residual crimp is preferably at least 0.016 mg / L, with respect to 2 / mm 6 Is:

number

[0085] The residual crimp (RS) of the tow material of the filter body should not exceed a value of 3.0, in particular should not exceed a value of 2.75, and the residual crimp (RS) of the tow material is preferably from about 1.5 to about 2.75, in particular from 1.9 to 2.5.

[0086] Residual crimp is understood as the ratio of the length of the final crimped cellulose acetate filaments to the length of the filter element. Residual crimp is a characteristic that characterizes a given filter element.

[0087] Surprisingly, it has been found that, under the same acetate weight, a relatively low total titer of filter body tow material requires a higher residual crimp value to maintain the required filter firmness.

[0088] A further aspect of the present invention relates to identifying a tow material for manufacturing a filter element for a mouthpiece to be used with a smoking product or HNB product, the tow material being optimized for the effectiveness of the filter element manufactured from the tow material and exhibiting the most consistent performance possible, particularly with respect to filtering performance and filter hardness.

[0089] In this context, it has also been determined that it is particularly important that the cellulose acetate filaments of the tow material exhibit a uniform, in particular predefined (predetermined) or definable, filament titre, in particular within the range of 5 to 10 denier.

[0090] To achieve consistent performance of filter elements made from tow material, particularly with respect to filtering performance and filter hardness, the coefficient of variation of the uniform filament titer should be at most 0.1, preferably at most 0.05 to at most 0.01.

[0091] The coefficient of variation of the uniform filament titer, also called the coefficient of deviation, is a statistical parameter that, in contrast to the variance, characterizes the relative measure of the distribution, i.e., it is independent of the units of measurement of the statistical or random variable.

[0092] In other words, what is guaranteed during the production of the tow material is that the individual filaments produced by each used spinneret of the spinning machine exhibit a uniform filament titer.

[0093] This can be achieved in practice by assigning each spinneret to its own, in particular frequency-controlled, spin pump, thereby ensuring that each spinneret of the spinneret is supplied with spin fluid (a solution of about 30% cellulose-2,5-acetate in acetone) in such a manner that a uniform nozzle pressure and a uniform amount of spin fluid can be delivered from each spinneret per unit time.

[0094] This approach, which is easily realizable but nevertheless effective, makes it possible to achieve a uniform filament titer, in particular one that is predefined or definable.

[0095] Alternatively or additionally, the monofilaments of the tow material formed from the cellulose acetate filaments preferably exhibit a uniform total titer, in particular a predefined or definable size of at least 5000 denier and at most 10,000 denier, the coefficient of variation of the uniform total titer being preferably at most 0.1, in particular at most 0.05 to at most 0.005, the coefficient of variation being in particular determined by multiple measurements over the length of the tow.

[0096] This easily implemented measure can effectively prevent quality variations during the production of the filter element of the present invention, which are unacceptable especially in the slim and ultra-slim type filter market and therefore involve productivity losses during the production of the filter element.

[0097] The advantages associated with the present invention are therefore many, in particular it is possible to realize slim and ultra-slim type filter elements in which the occurrence of the high temperature collapse phenomenon is effectively prevented, even when the tow material of the filter body has a relatively low total titer and a relatively low filament titer. The invention according to the present disclosure includes the following aspects: <Aspect 1> 1. A filter element for a mouthpiece for use in a smoking product or HNB product, comprising: The filter element has a filter body made of a tow material, the tow material being formed by a plurality of monofilaments of cross-linked and crimped cellulose acetate filaments, the cellulose acetate filaments exhibiting, in particular, a multilobal or polygonal, preferably Y-shaped, cross-sectional shape: the cellulose acetate filaments of the tow material exhibit a uniform filament titre, which is in particular predefined or definable, ranging from less than or equal to 10 denier (11.1 dtex) to more than or equal to 5 denier (5.5 dtex), - the tow material has a total titer in the range of 10,000 denier (11.1 kdtex) or less and 5,000 denier (5555.5 dtex) or more; and - the specific fiber weight of the cellulose acetate filaments of the tow material is equal to or less than 2.5 mg per mm of filter element length and equal to or greater than 1.0 mg per mm of filter element length; Filter element. <Aspect 2> 2. The filter element according to aspect 1, wherein the coefficient of variation of the uniform total titer is at most 0.1, preferably at most 0.05 to at most 0.005. <Aspect 3> 3. The filter element according to aspect 1 or 2, wherein the coefficient of variation of the uniform filament titer is at most 0.1, preferably at most 0.05 to at most 0.01. <Aspect 4> The filter body is particularly embodied as a filter rod, and preferably has a diameter of about 6 mm to about 4 mm, in particular about 5.5 mm to about 5.0 mm, preferably about 5.35 mm; At least a portion of the filter body is wrapped in paper or a paper-like material. The filter element according to any one of embodiments 1 to 3. <Aspect 5> 5. The filter element of claim 4, wherein the filter body with the paper or paper-like wrapping has a compression depth of less than 0.90 mm, in particular less than 0.85 mm, when a face end of a cylindrical test piece having a mass of 300 g and a diameter of 12 mm is placed on the filter body perpendicular to the filter body axis. <Aspect 6> 5. The filter element of claim 4, wherein the filter body without the paper or paper-like wrapping has a compression depth of less than 0.90 mm, particularly less than 0.85 mm, when a face end of a cylindrical test piece having a mass of 300 g and a diameter of 12 mm is placed on the filter body perpendicular to the filter body axis. <Aspect 7>

[0023] Aspect 7. The filter element of any one of aspects 1-6, wherein at least some of the cellulose acetate filaments of the monofilaments of the tow material are at least partially formed as hollow and / or tubular cellulose acetate filaments. <Aspect 8> A filter element according to any one of the preceding embodiments, wherein the hardness of the filter body reaches at least 80% of Filtrona hardness, preferably at least about 86% of Filtrona hardness. <Aspect 9> The filter body contains a plasticizer, and has a plasticizer content of about 2% to about 15%, preferably about 4% to about 10%, and the plasticizer particularly includes triacetin, triethylene glycol diacetate, and / or citric acid ethyl ester. The filter element according to any one of embodiments 1 to 8. <Aspect 10> The tow material of the filter body exhibits a residual crimp (RS) and a density (ρ), and a relationship value A between the residual crimp and the density is as follows:

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Claims

1. 1. A filter element for a mouthpiece for use in a smoking product or HNB product, comprising: The filter element has a filter body made of a tow material, the tow material being formed by a plurality of monofilaments of crosslinked and crimped cellulose acetate filaments, the monofilaments comprising: the cellulose acetate filaments of the tow material exhibit a uniform filament fineness, which is in the range of less than or equal to 10 denier (11.1 dtex) and more than or equal to 5 denier (5.5 dtex); - the tow material has a total fineness in the range of less than or equal to 10,000 denier (11.1 kdtex) and more than or equal to 5,000 denier (5555.5 dtex); and - the specific fiber weight of the cellulose acetate filaments of the tow material is equal to or less than 2.5 mg per mm of filter element length and equal to or greater than 1.0 mg per mm of filter element length; Filter element.

2. 2. The filter element of claim 1, wherein the coefficient of variation of the uniform total fineness is at most 0.

1.

3. 3. The filter element of claim 1, wherein the coefficient of variation of the uniform filament fineness is at most 0.

1.

4. At least a portion of the filter body is wrapped in paper or a paper-like material.

3. A filter element according to claim 1 or 2.

5. 3. The filter element of claim 1 or 2, wherein at least some of the cellulose acetate filaments of the monofilaments of the tow material are formed at least in part as hollow and / or tubular cellulose acetate filaments.

6. the filter body contains a plasticizer and has a plasticizer content of about 2% to about 15%; 3. A filter element according to claim 1 or 2.

7. The tow material of the filter body exhibits a residual crimp (RS) and a density (ρ), and a relationship value A between the residual crimp and the density is as follows: [Equation 1] at least 0.016 mg ２ / mm ６ 3. The filter element according to claim 1, wherein:

8. 3. A filter element according to claim 1 or 2, A filter element wherein the residual crimp (RS) of the tow material of said filter body does not exceed a value of 3.

0.

9. A mouthpiece for use with a smoking product or HNB product, comprising a filter element according to claim 1 or 2.

10. A cigarette filter or cigarette filter element comprising the filter element according to claim 1 or 2.

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