Filter element for a mouthpiece for a smoking product or an HNB product

Abstract

The present invention relates to a filter element for a mouthpiece for use in a smoking or HNB product. The filter material has 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 have a cross-sectional shape that is particularly polygonal, preferably Y-shaped, and the tow material has a length of 0.15 m. 2 / g, more particularly less than 0.3m 2 / g, less than 0.025m 2 / g or more.

Description

Technical Field

[0001] The present invention relates to a filter element for a mouthpiece used in a smoking product or an HNB product, and the use of such a filter element in a mouthpiece for a smoking product or a cigarette filter or a mouthpiece for an HNB product, respectively.

[0002] The smoking products meant by the present invention are related to traditional tobacco products, especially cigarettes, but also include pipes, marijuana products, so-called heat-not-burn (HNB) products, VAPE products, and so-called hybrid products.

Background Art

[0003] Depending on the application, mouthpieces for using smoking products have different functions. On the one hand, for example, a mouthpiece can function as a filter device that removes harmful components such as condensate, especially tar, and particulate matter entrained in the smoke flow, from the smoke flow of tobacco. This filter function is especially used in conventional tobacco applications. The corresponding mouthpiece is thereby formed as an integral part of a cigarette or cigarillo and can thus form the "tip" of the cigarette / cigarillo.

[0004] Another example of a type of mouthpiece relates to a replaceable device such as a replaceable filter element that can be removed after use. Such a mouthpiece is housed in a suitable holder, such as a cigarette holder or a pipe mouthpiece.

[0005] One of the components essential to a cigarette is the cigarette filter, which is part of the mouthpiece. The tobacco filter is designed to reduce the proportion of harmful substances such as condensed water and gas contained in tobacco smoke. Furthermore, for many smokers, the filter somewhat mellows the smoke and improves the mouthfeel. In conventional filtered cigarettes, the filter is wrapped in filter wrapper paper and connected to the tobacco rod via so-called tipping paper, and thus most industrially manufactured cigarettes are equipped with a filter.

[0006] In particular, a number of types of filter materials have already been used to reduce the substances contained in tobacco smoke before they reach the smoker's respiratory system. However, a satisfactory filter needs to be effective not only in removing large amounts of harmful substances, but also in not undesirably obstructing the passage of air and smoke through the filter and not imposing excessive resistance on the filter. However, when using a tobacco smoke filter, the filter material must not change the taste of the tobacco smoke by adding its own flavor.

[0007] The present invention relates not only to the conventional filter materials for tobacco use described above, but particularly to filter materials and / or filter elements for mouthpieces used in smoking products, whereby these filter elements have, in particular, functions other than just the filtering function.

[0008] In other applications, the filtering function is never a priority for the mouthpiece. For example, this applies to heat-not-burn products (''HNB products''), which have become increasingly popular in recent years. In such devices, a portion of the processed tobacco is heated by a heat source during use, but not burned. As a result, volatile components of the tobacco such as flavorings, nicotine, glycerin, and water vaporize and are entrained in the air that the user inhales through the HNB product. When the released substances cool, an aerosol is formed and inhaled by the user.

[0009] Commercially available HNB products typically consist of a power source for supplying a heating element, a separate consumable consisting of 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 in the form of a crimped polylactic acid film bundled in a cylinder having a number of axial flow channels, and a mouthpiece filter. The consumable is inserted into the device before use such that the heating element heats the tobacco portion during use of the HNB product.

[0010] For example, in the products of Philip Morris called IQOS® / HEETS®, the tobacco portion is penetrated by a heating blade in the device. IQOS® / HEETS® products refer to the IQOS® device sold by Philip Morris and the HEETS® products of the consumables associated therewith. The consumable HEETS® product is a non-heated product that is only heated instead of the tobacco being burned.

[0011] The competing products of BAT ("Glo®") heat the tobacco from the outside, and the so-called cooling element is replaced by a tube. Also in these devices, a portion of the processed tobacco is heated by a heat source during use, but it does not burn. Volatile tobacco components such as flavorings, nicotine, glycerin, and water are vaporized thereby and entrained in the air inhaled by the user through the HNB product. When the released substances cool, an aerosol is formed and inhaled by the user.

[0012] Known consumables for this application have the drawback that the mouthpiece filter is significantly heated because it is close to the heating element and due to the high-temperature steam generated during use of the HNB product.

[0013] In so-called hybrid products, first, an aerosol generating agent is vaporized (propylene glycol, glycerin), and an aerosol is generated by cooling. This aerosol is jetted through a part of the processed tobacco and inhaled by the consumer. Also in such applications, the mouthpiece has a special function of protecting the end on the user side from being heated to an uncomfortable degree for the user.

[0014] In contrast to conventional tobacco products that burn tobacco, in the case of consumables of HNB products, it may be desirable that elements arranged downstream in the flow direction of the heated tobacco part, such as a cooling element or a mouth-side filter, have only a low filtering effect with respect to condensed components of smoke such as tar.

Summary of the Invention

Problems to be Solved by the Invention

[0015] The present invention is based on the problem of identifying a filter element for a mouthpiece used in a smoking product or an HNB product, and the filter element is suitable for a wide range of applications of smoking products. In particular, it is to define a filter element having a low draw resistance and a low filtration performance, showing a sufficiently high filter hardness that is as constant as possible when used in a smoking product, and nevertheless, the filter element can be manufactured particularly economically.

[0016] Furthermore, the filter element particularly shows a selective filtration effect against phenols and is suitable for reliably cooling a gas containing heated particles, and it is desirable that the temperature of the gas, aerosol or vapor taken in by the user from the smoking product can be lowered.

Means for Solving the Problems

[0017] These and other problems are solved by the subject matter of independent claim 1.

[0018] Accordingly, the present invention relates in particular to a filter element for a mouthpiece for use with a smoking product or an HNB product, the filter element having a filter body made of tow material, whereby the tow material is formed by a plurality of individual filaments of cross-linked and crimped cellulose acetate filaments, whereby the cellulose acetate filaments exhibit in particular a polygonal, preferably Y-shaped cross-sectional shape.

[0019] It has surprisingly been found that in this type of filter element, a desired reduced filtration performance with respect to condensable components such as tar and sufficient filter hardness can be achieved while maintaining in particular the total titer of the tow material if the tow material exhibits the lowest possible mass-based specific surface area.

[0020] The tow material of the filter element according to the invention preferably has a mass-based specific surface area of less than 0.3 m 2 / g, in particular less than 0.15 m 2 / g and more than 0.025 m 2 / g. Such mass-based specific surface area values, preferably between 0.3 m 2 / g and 0.025 m 2 / g, can significantly improve the performance and scope of application achievable with the filter element.

[0021] According to a preferred embodiment of the filter element of the present invention, the cellulose acetate filter element of the tow material exhibits at least partially a three-leaf shape, i.e., a star-shaped cross-sectional shape with three arms. Such a cross-sectional shape is suitable for enabling the cellulose acetate filaments to have the largest possible specific surface area while enabling the economical use of raw materials when a high filtration capacity is desired, for example like that of conventional cigarettes. Alternatively, it is possible to obtain a desired large specific surface area using a bundle of extremely fine filaments with a circular cross-section. However, other cross-sectional shapes of the cellulose acetate filaments, such as polygonal or quadrilateral cross-sectional shapes, are also conceivable.

[0022] The tow material of the filter element of the present invention is formed from cellulose acetate filaments crimped in a continuous stuffer box. A solution of about 30% cellulose-2,5-acetate in acetone is pressed through a spinneret thereby, and the acetone evaporates in the spinning chamber, and a plurality of cellulose acetate filaments are gathered in a band and crimped in a stuffer box. Thereafter, the product is dried and usually pressed to become a veil. The tow material ("filter tow") is taken out from the veil and processed into a filter rod by a filter rod machine. The filter tow is drawn in a drawing device, additives for binding cellulose acetate filaments are added, after forming a so-called roving, it is axially compressed, optionally wrapped in paper, and cut to the final length of the filter element.

[0023] Regarding the tow material of the filter element of the present invention, especially 0.3 m 2 less than / g, especially 0.15 m 2 less than / g, 0.025 m 2 By inventively selecting a mass-based specific surface area in the range of / g or more, it is possible to realize a filter element that achieves a desired reduced filtration performance with respect to condensable components while still achieving sufficient filter hardness to maintain full strength.

[0024] According to an embodiment of the filter element of the present invention, the cellulose acetate filaments of the individual filaments of the tow material are formed as at least partially hollow and / or tubular cellulose acetate filaments.

[0025] What is particularly understood by the hollow / tubular cellulose acetate filaments is preferably a cylindrical filament showing one or more continuous cavities when viewed in cross-section.

[0026] Such hollow fibers can be designed at least partially as multi-lumen hollow fibers. Compared to "solid" cellulose acetate filaments, single lumen or multi-lumen tubular cellulose acetate filaments are considerably resistant to kinking, which allows for a particularly high filter loader hardness to be achieved without increasing the compression of the material.

[0027] According to an embodiment of the present invention, the hollow cellulose acetate filament exhibits at least partially a triangular star-shaped, i.e., three-armed star-shaped cross-sectional shape. Such a cross-sectional shape is suitable when the cellulose acetate filament has the largest possible specific surface area, for example enabling high filtration capacity while allowing for economical use of raw materials.

[0028] Alternatively, it is also possible to obtain a desired large specific surface area by using a bundle of ultra-thin filaments with a circular cross-section. However, other cross-sectional shapes of the hollow cellulose acetate filament, such as a quadrilateral cross-sectional shape, are also conceivable.

[0029] Since the filter element of the present invention consists of a filter body that can be at least partially based on cellulose acetate filaments at least partially formed as hollow cellulose acetate filaments, the filaments of the filter element at least partially formed as hollow cellulose acetate filaments have a small external surface area relative to the total fiber volume, so that a low draw resistance and a low filtration performance can be achieved.

[0030] Among these, since the filaments are partially formed as hollow cellulose acetate filaments, it has surprisingly been found that a particularly high filter loader hardness can be achieved with the filter element.

[0031] 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 filter hardness with a lower fiber weight per unit volume.

[0032] Since 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 mouthpiece tip for, for example, a cigarette tobacco rod, thereby further realizing a selective phenol filtration effect.

[0033] By using a filter element based on cellulose acetate filaments, it is possible to manufacture a filter rod for cigarettes that exhibits clearly excellent properties with respect to specific retention phenomena, particularly from the viewpoints of smoking and health.

[0034] Filters made of cellulose acetate filter harmful nitrosoamines and phenols much more efficiently than condensed water and nicotine. Furthermore, smokers rate the taste of combining today's customary tobacco blends such as "American Blend", "German Blend", "Virginia" with filter rods made of cellulose acetate as the most delicious. A further advantage of cellulose acetate filter rods can be found in the optical homogeneity of the cut surface of the filter.

[0035] Since the filter element of the present invention is formed at least in part from hollow cellulose acetate filaments that function as a filter material according to an embodiment, a wide range of various draw resistances and filtration performances can exist in filter rods made of the material of the present invention.

[0036] In particular, it has been shown that filter materials consisting at least in part of hollow cellulose acetate filaments exhibit an improved heat cooling effect. It has also been found that even when using hollow cellulose acetate filaments as filter materials, a very low filter effect, i.e., retention effect, can be achieved with respect to the suspended substances and gases to be removed.

[0037] This effect is presumably achieved because the surface or flow of the gas or air to be purified is changed by the hollow cellulose acetate filaments in such a way that it retains only little of the potential suspended matter in the gas / air. Another reason could be that by using hollow cellulose acetate filaments, a different and particularly advantageous surface structure of the filter material can be achieved.

[0038] The filter element of the present invention further has the advantage of enabling variable cooling of gases (especially aerosols) containing particularly heated particles, such that the temperature of the gases, aerosols or vapors inhaled by the user of a smoking product or an HNB product can be selectively reduced. By varying the proportion of hollow cellulose acetate filaments in the filter and / or the filter material, the desired cooling effect can be specifically adapted to the application.

[0039] A further important point to note is that the flow within the filter element of the present invention is essentially around the hollow cellulose acetate filaments (= hollow fibers) and rarely passes through the hollow fibers. From a geometric consideration, it is clear that the distance between the fibers will thereby be considerably larger than the lumen (hollow part) of the hollow fibers. The viscosity of the aerosol (substantially air) causes it to take the least resistant path (i.e., it flows between the individual filaments rather than through them).

[0040] In other words, since there is no flow through the hollow cellulose acetate filaments of the filter material, the active filtration surface is never maximized in embodiments of the filter element of the present invention.

[0041] In particular, the hollow cellulose acetate filaments can thus have kinks that close the lumen of the hollow cellulose acetate filaments without affecting the performance of the filter and / or filter material of the present invention with respect to the set target parameters.

[0042] Of particular note in this context is that the hollow cellulose acetate filaments realized as hollow fibers need not be continuously hollow, but rather may be partially closed by kinks. They may also deviate from the ideal circular shape.

[0043] Embodiments of the present invention provide that the hollow cellulose acetate filaments of the tow material function as a support material on the one hand and as a cooling material on the other hand. By the hollow cellulose acetate filaments simultaneously serving as a support material, a particularly compact filter element can be realized without the need to increase the dimensions of the smoking article.

[0044] As used herein, the term "filter roller hardness" refers to the filter hardness determined according to the principle of the filter roller. In this principle, the filter hardness is determined by pressing the flat front end of a cylindrical rod with a diameter of 12 mm vertically against a horizontally arranged filter rod with a load of 300 g. The ratio of the compressed diameter to the diameter at the first contact becomes the filter roller hardness percentage.

[0045] The hardness of each of the filter element or the filter rod is an important target criterion, especially for cigarette filters. This is generally expressed as the so-called filter roller hardness. It should be noted here that the filter roller hardness is measured only for the filter element and not for the underlying (raw) filter material, i.e., the tow material. The filter roller hardness of the filter element is particularly affected by the amount of triacetin that can be sprayed on the filter element.

[0046] The lower limit of the filter loader hardness is about 88%, which meets the market requirements. The filter loader hardness of the filter element can preferably be set to about 88% - 95%, particularly about 90% - 93%.

[0047] A preferred embodiment of the filter element of the present invention provides that the filter body is realized particularly as a filter rod, preferably having a diameter between about 8 mm and about 5 mm, particularly a diameter of about 7.8 mm or about 5.35 mm, and at least a part of the filter body is wrapped with paper or paper-like material.

[0048] In this embodiment, the filter loader hardness of the filter element is preferably 85% or more, particularly 90% or more.

[0049] The filter loader hardness is particularly determined by the fiber weight per volume for a given filter diameter, and the filament titre of the cellulose acetate filament of the tow material has little influence on the filter loader hardness.

[0050] The configuration of the filter element of the present invention provides that the filter body has a fiber weight corresponding to a maximum of 10 mg / mm of the filter element length.

[0051] The filter loader hardness of the filter element can also be achieved by using a stronger filter wrap paper or a stronger tipping paper.

[0052] Tipping paper refers to paper in which a plurality of filter elements are joined, or paper in which a filter element is connected to a tobacco rod. However, increasing the filter loader hardness of the filter element by using a stronger filter wrap paper or a stronger tipping paper is economically disadvantageous in this approach because higher costs are expected.

[0053] In relation to the filter hardness of the filter element, there is a so-called "thermal collapse" in which the filter hardness decreases as the filter element is used, i.e., as the filter element is used with a smoking or HNB product. This phenomenon can occur especially with traditional cigarettes when the filter element is heated in the presence of moisture during the last puff, but this undesirable effect can also occur with HNB products.

[0054] In this context, when using a tow material having a mass-based specific surface area of less than 0.15 m 2 / g as the base material of the filter element of the present invention, it has been shown that the degree of decrease in filter hardness due to the "thermal collapse" phenomenon can be significantly reduced.

[0055] When the tow material of the filter body of the filter element of the present invention has a mass-related specific surface area of 0.3 m 2 / g to 0.025 m 2 / g, particularly less than 0.15 m 2 / g, it is possible to reduce the draw resistance and filtration performance of the filter element of the present invention without shortening the length of the filter element. Therefore, a relatively long filter element can realize a corresponding long cooling section, which is advantageous for the heat balance, especially when the filter element is used in an HNB product.

[0056] In addition, by specifying the mass-related specific surface area of the tow material to be less than 0.15 m 2 / g in the specifications of the present invention, it is possible to reduce the draw resistance and filtration performance of the filter element without reducing the fiber weight in the filter element per volume fraction and / or without reducing the total titre of the tow material. This has the advantage that there is no decrease in the filter hardness of the filter element due to a decrease in the fiber weight in the filter element per volume fraction and / or a decrease in the total titre.

[0057] According to an embodiment of the filter element of the present invention, the filter body has a fiber weight of up to 10 mg / mm of the filter element length. The tow material constituting the base product for the manufacture of the filter element of the present invention should in particular exhibit a total titre of 10,000 to 40,000 denier.

[0058] The cellulose acetate filaments of the tow material serving as the base material for manufacturing 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.

[0059] It is preferably used for the plasticization, in particular the thermoplasticization, of cellulose acetate fibers, and the plasticizer applied to the fibers can be selected, for example, from the following group: glycerol esters (in particular glycerol triacetate), ethylene carbonate and propylene carbonate, citrate esters (in particular acetyl citrate, triethyl citrate), glycol esters or diethylene glycol dibenzoate.

[0060] A person skilled in this technical field is proficient in the amount of plasticizer and / or water-soluble binder to be used. Generally, there is a plasticizer and / or binder content of about 1 to 14% by weight, but in special cases, the plasticizer content can easily exceed this range.

[0061] The water-soluble binder preferentially present on the surface of the cellulose acetate filaments can be in particular a polyalkylene oxide, a water-soluble ester or ether, starch, a starch derivative, p-polyvinyl alcohol, a polyvinyl ether, p-polyvinyl acetate and / or a polysaccharide, a water-soluble polyamide and a polyacrylate, or a high-boiling solvent applied to the individual filaments of the tow material or to the tow material.

[0062] In this example, it was particularly recognized that the residual shrinkage (RS) of the tow material of the filter body and the density (ρ) of the filter body also have a great influence on the performance of the filter element. Thereby, the density value A related to the residual shrinkage is preferably at least 0.016 mg 2 ×mm 6 as follows:

Number

[0063] Thereby, in particular, the residual shrinkage (RS) of the tow material of the filter body must not exceed a value of 1.7, in particular a value of 1.45, and the residual shrinkage (RS) of the tow material is preferably between about 1.05 and about 1.4, in particular between 1.1 and 1.3.

[0064] Thereby, the residual shrinkage is understood as the ratio of the length of the finally wound cellulose acetate filament to the length of the filter element. The residual shrinkage is a characteristic of a given filter element.

[0065] A further aspect of the present invention relates to specifying a tow material for manufacturing a filter element for a mouthpiece used with a smoking product or an HNB product, the tow material being such that the filter element manufactured from the tow material exhibits the most stable possible performance, particularly in terms of filtration performance and filter hardness.

[0066] In this context, and thereby particularly determined to be important, is that in particular the cellulose acetate filaments of the tow material have a predefined or definable uniform filament titre. This predefined or definable uniform filament titre is in the range of particularly 8 to 30 denier, preferably in the range of 9 to 30 denier, more preferably in the range of 10 to 20 denier.

[0067] In order to achieve stable performance of the filter element made of tow material, particularly filtration performance and filter hardness, the coefficient of variation of the uniform filament titre should be at most 0.1, preferably at most 0.05 to at most 0.01.

[0068] The coefficient of variation of the uniform filament titre, also called the coefficient of deviation, is a statistical parameter that, in contrast to variance, characterizes the relative measure of variance. That is, it does not depend on the unit of measurement of the statistical or probability variable.

[0069] In other words, it is ensured during the production of the tow material that each filament produced by each spinneret used in the spinning machine exhibits a uniform filament titre.

[0070] This can actually be achieved by assigning a unique, particularly frequency-controlled spinning pump to each spinneret in order to ensure that the spinning solution (a solution of approximately 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 solution supplied from each spinneret per unit time are possible.

[0071] By this simple yet effective approach, it is possible to achieve a particularly predefined or definable uniform filament titre.

[0072] Alternatively or in addition, it is preferred that each filament of the tow material formed from cellulose acetate filaments exhibits a predefined or definable, preferably uniform, filament titre of at least 200 denier and at most 4000 denier, preferably at least 250 denier and at most 2500 denier, where the coefficient of variation of the uniform filament titre is preferably at most 0.1, particularly at most 0.05 to at most 0.01.

Claims

1. A filter element for a mouthpiece for use with a smoking product or an HNB product, the filter element having a filter body made of a tow material, the tow material being formed by a plurality of individual filaments of crosslinked and crimped cellulose acetate filaments, the cellulose acetate filaments exhibiting a polygonal cross-sectional shape, and the tow material being less than 0.15 m ２ / g and at least 0.025 m ２ / g, and The tow material of the filter body has a residual shrinkage (RS) and a density (ρ), whereby a density value A related to the residual shrinkage reaches at least 0.016 mg ２ ×mm ６ as follows A filter element. 【Number 1】

2. The filter element according to claim 1, wherein the residual shrinkage (RS) of the tow material of the filter body does not exceed a value of 1.7, whereby the residual shrinkage (RS) of the tow material of the filter body is between 1.1 and 1.

7.

3. The filter element according to claim 1 or 2, wherein the filter body has a fiber weight, whereby the fiber weight of the filter body reaches a maximum of 10 mg / mm of filter length.

4. The filter element according to any one of claims 1 to 3, wherein the cellulose acetate filaments of the tow material have a predefined or definable uniform filament titre, and the predefined or definable uniform filament titre is between 8 denier (8.88 dtex) and 30 denier (33.33 dtex).

5. The filter element according to claim 4, wherein the coefficient of variation of the uniform filament titre is between a maximum of 0.1 and a maximum of 0.

01.

6. The filter element according to any one of claims 1 to 5, wherein the individual filaments of the tow material formed from cellulose acetate filaments exhibit a predefined or definable filament titre of at least 200 denier (222 dtex) and a maximum of 4000 denier (4.444 dtex).

7. The filter element according to claim 6, wherein the coefficient of variation of the uniform filament titre is between a maximum of 0.1 and a maximum of 0.

01.

8. The filter element according to any one of claims 1 to 7, wherein the filter body is realized as a filter rod and has a diameter between 8 mm and 5 mm, whereby at least a part of the filter body is wrapped with paper or a paper-like material.

9. The filter element according to any one of claims 1 to 8, wherein the cellulose acetate filaments of the individual filaments of the tow material are formed as at least partially hollow and / or tubular cellulose acetate filaments.

10. The filter element according to any one of claims 1 to 9, wherein the hardness of the filter body is at least 80% of the filter roller hardness.

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