RU2799593C1 - Filter material and/or filler material for a mouthpiece for use with a smoking product or hnb product, mouthpiece and cigarette filter containing such filter material and/or filler material, and method for producing such filter material and/or filler material - Google Patents

Abstract

FIELD: smoking products.

SUBSTANCE: group of inventions is related to filter materials and/or mouthpiece filler material for use with smoking products. In the process, a solution of cellulose acetate having an acetyl number of at least 53% in acetone is forced through a spinning machine having a plurality of holes. The cellulose acetate filamentary fibres are then cut into cellulose acetate staple fibres as needed, and the plurality of cellulose acetate filamentous fibres and/or cellulose acetate staple fibres thus obtained are collected into a filter tow, optionally crimped depending on the requirements. The spinning machine is designed so that the hollow cellulose acetate fibres are twisted, while the hollow area in the filter and/or filler material - with respect to the cross section orthogonal to the fibres of the filter and/or filler material - is 25-90%, and preferably 50-80% . The fibre diameter of the cellulose acetate filamentous fibres is in the range between 60-100 mcm.

EFFECT: possibility of regulation of draft resistance, filtration characteristics, cooling effect, hardness is ensured.

22 cl

Description

The present invention relates to a filter material and/or mouthpiece fill material for use with smoking articles or HNB products, as well as the use of such filter material and/or fill material in smoking article mouthpieces or cigarette filters or HNB mouthpieces. , respectively. According to a further aspect, the invention relates to a process for producing such filter material and/or fill material.

Smoking articles within the meaning of the present invention refer to traditional tobacco products, cigarettes in particular, as well as pipes and marijuana products, as well as so-called non-burning tobacco heating (HNB) products, vaping products and so-called hybrid products.

Mouthpieces for use with smoking articles have different functions depending on the application. First, the mouthpieces can serve as a filter device, for example, to draw in harmful elements such as tar-like condensate along with particulate matter entrained in the stream of tobacco smoke from smoking. This filtering function is particularly used in traditional tobacco applications. The corresponding mouthpiece can thus be formed as an integral part of the cigarette or cigarillo and thus form the "tip" of the cigarette or cigarillo.

Replacement devices of another type of mouthpiece are, for example, replacement filter elements adapted to be removed after use. Such mouthpieces are placed in suitable holders, such as a cigarette holder or a pipe mouthpiece.

One mouthpiece, shaped as an integral part of the cigarette, is the cigarette filter. The cigarette filter is meant to prevent the percentage of harmful substances such as condensate and gases in cigarette smoke. The filter additionally makes the smoke somewhat softer or more pleasant for a large percentage of smokers. In a conventional filter cigarette, the filter is enclosed in the filter wrapping paper and attached to the tobacco bundle by a so-called rim paper, whereby most commercially produced cigarettes are provided with a filter. Those who roll them themselves can buy them from tobacco shops.

Numerous types of filter materials have already been used, in particular to reduce the levels of substances in tobacco smoke before they reach the smoker's respiratory system. Still in addition to removing large amounts of harmful elements, a satisfactory filter must also be effective without undesirably obstructing the passage of air or smoke through the filter and thus necessitating overtightening on it. When used in tobacco smoke filters, however, the filter material must also not alter the taste of tobacco smoke by adding its own flavor.

An additional important factor in the production of a satisfactory tobacco smoke filter is that its production is not too complicated so as not to unduly raise the final price of the smoking article in which the filter is used.

However, the present invention relates less to filter elements for the traditional tobacco applications described above, but rather, in particular, to filter materials and/or fill materials for mouthpieces used in smoking articles, whereby these filter materials and/or fill materials, in in particular, have other functions than just the filtering function.

In other applications, the filtering function of the mouthpiece is actually not the main concern at all. This applies, for example, to non-combustible heating products ("HNB products"), which have become increasingly popular in recent years. In these devices, a portion of the processed tobacco is heated by a heat source during use, but is not burned. The volatile components of tobacco such as flavors, nicotine, glycerin and water are thus vaporized and entrained in the air that the user draws in through the HNB product. As the released substances cool, an aerosol is formed which is inhaled by the user.

Commercially available HNB products typically comprise a device consisting of a power source that powers a heating element and a separate consumable consisting of a portion of the processed tobacco, a support element such as, for example, a tubular cellulose acetate section, a so-called cooling element, placed lower in the direction of flow, for example in the form of a crimped polylactide film laid in a cylinder with multiple axial channels, like a filter on the side of the mouth. The consumable products are inserted into the device prior to use so that the heating element heats up a portion of the tobacco while the HNB product is being used.

For example, in a Philip Morris product called IQOS/HEETS, a portion of the tobacco is pierced by a heating blade in the device. IQOS/HEETS product refers to an IQOS device with an associated HEETS consumable product sold on the market by Philip Morris. The consumed HEETS product is a heated but not combustible product in which the tobacco is merely heated instead of being burned.

A competing product from BAT ("Glo") heats the tobacco from the outside, replacing the so-called cooling element with a pipe. In these devices, too, a portion of the processed tobacco is heated by the heat source during use, but is not burned. The volatile components of tobacco such as flavors, nicotine, glycerin and water are thus vaporized and entrained in the air that the user draws in through the HNB product. As the released substances cool, an aerosol is formed which is inhaled by the user.

Known consumable products for this application suffer from the disadvantage that their mouth-side filters can heat up significantly due to their proximity to the heating element and due to the hot steam generated during use of the HNB product.

In the so-called hybrid products, the aerosol generator first evaporates (propylene glycol, glycerin); cooling creates an aerosol. This aerosol is directed through a portion of the processed tobacco and inhaled by the consumer. In such applications, too, the mouthpiece has the particular function of protecting the end on the user's side from being heated to an unpleasant degree for the user.

In contrast to traditional tobacco products that burn tobacco, it may be desirable in the case of HNB product consumables for elements located downstream of the heated portion of the tobacco in the flow direction, such as the cooling element and the mouth-side filter, to have only a low filtering the effect of relatively condensed components such as tar, since these smoke components can occur in much smaller quantities.

The materials required to form the mouthpiece for smoking articles must therefore be adapted, and in particular adaptable, to the physical properties of the smoke (temperature, flow profile, etc.) and to the chemical composition. Conventional cigarette filters, as well as HNB products in particular, have a number of target parameters that must be adjusted or suitably satisfied through proper selection and configuration of mouthpiece materials. This applies in particular to the following targets, which should be briefly discussed below:

- traction resistance

- filtration characteristic

- filter rod hardness / Filtron hardness

- visual appearance

- profitability of obtaining

- smoke temperature

The hardness of the filter rod is an important target criterion for cigarette filters. It is typically stated as the so-called Filtron hardness. The Filtron hardness is determined by vertically pressing the flat front end of a 12 mm diameter cylindrical rod onto a horizontally positioned filter rod with a load of 300 g. The ratio of the compressed diameter to the original diameter previously determined at first contact results in the Filtron hardness percentage.

It should be emphasized that the Filtron hardness is measured only on the filter, but not on the underlying (raw) material of the filter.

The minimum Filtron hardness limit is approximately 88% and is linked to market requirements. The Filtron hardness of the cigarette filter can thus preferably be set to about 88%-95%, in particular about 90%-93%.

In traditional cigarette filters, Filtron hardness is primarily determined by the weight of fiber per unit volume for a given filter diameter. The linear density of the fiber, in particular, has only a minimal effect on the Filtron hardness.

At times, a reinforced filter wrapping paper or a reinforced tipping paper will also achieve a higher Filtron hardness. Rim paper is a paper in which either a plurality of filter elements are bonded together or the filter elements are bonded to a tobacco rod. However, increasing the Filtron hardness with reinforced filter wrapping paper or reinforced tipping paper has an economic disadvantage, as higher costs can be expected with this approach.

Associated with the Filtron hardness is the so-called "hot breaking" in which the hardness of the filter decreases during smoking. In a conventional cigarette, this may in particular occur when the filter is heated in the presence of moisture during one of the last puffs. This undesirable effect can also occur with HNB products.

In addition to a Filtron hardness that is as constant and as high as possible during use of the smoking article, the mouthpiece material must also exhibit a predetermined or determinable filtration characteristic. Filtration performance in terms of condensed matter (droplets, particles), also referred to as condensate or tar, is of interest in relation to traditional tobacco products as well as HNB products because condensed matter contains many substances of harmful health significance.

In conventional products, the filtration characteristic (together with other influencing factors such as tobacco blend, ventilation, etc.) is chosen to control the "exhaust" of the cigarette (the level of smoke constituents in the smoke that the smoker inhales). In many markets, legal regulations set "exhaust" at the upper limit. Below the legal standard, "exhaust" can be tailored to consumer preferences.

In HNB products, the aerosol has much less condensed matter of negative health significance compared to the case with traditional products. In addition, since more desirable materials such as flavors and nicotine are likewise present in the condensate, the goal here is to select the lowest possible filtration performance, however, without allowing it to drop to zero.

Note with respect to the "drag resistance" target parameter that consumers show a preference for a certain range of drag resistance when using a tobacco product. In conventional cigarettes, the filter (in addition to controlling "exhaust") serves to control the drag resistance of the cigarette.

In HNB products, however, the drag resistance assisted by the mouth-side filter (mouthpiece) should tend to be as low as possible, since other components of the HNB device, in particular the tobacco heated portion and the device, already provide a high contribution. in traction resistance. The low drag resistance of the filter (mouthpiece) leads to degrees of freedom that apply to other components of the HNB device that are desirable.

In addition, draft resistance and filtration performance are closely related. Both can be reduced in a variety of ways, although this often negatively affects the other parameters.

For example, draft resistance and filtration performance can be reduced by reducing the length of the filter. But once the length of the filter becomes smaller than the diameter of the filter, the workability becomes problematic. A shorter filter also leads to a shorter cooling path, which is problematic for heat balance.

Alternatively, or in addition, the draft resistance and filtration performance can be reduced by reducing the weight of the fiber in the filter material by volume content and/or total denier. However, this has the disadvantage of reducing the Filtron hardness and may no longer be able to achieve the minimum hardness.

Alternatively, or in addition, the drag resistance and filtration performance can be reduced by increasing the linear density of the fiber. With a constant filter diameter and a fixed fiber weight per unit volume, filtration performance and draw resistance decrease with increasing fiber linear density, which is desirable for HNB products compared to traditional products. This also does not adversely affect the hardness, since, as stated above, the Filtron hardness only slightly depends on the linear density of the fiber.

It should be noted with respect to the target parameter "visual appearance" that the consumer prefers a mouthpiece having a flat, white cross-sectional area on the side of the mouth. There are, however, also tube-shaped products on the side of the mouth.

It should be noted with regard to smoke temperature that smoke temperature is not a problem in today's conventional products. In addition, smoke temperatures are noticeably high in traditional HNB products and uncomfortably high for some users. In addition, commercial HNB products require refrigeration in order to cool the evaporated components, so that an aerosol of the gaseous components is initially formed.

In commercially available HNB products, the distance from the heating element of the mouth end of the HNB product is of course the most important parameter for cooling the aerosol. Thus, for example, it is known to place a so-called cooling element downstream of the tobacco section and the support element. The cooling element may be in the form of a crimped polylactide film or in the form of a cardboard tube - whereby - in addition to cooling - this element, located downstream of the tobacco area, and the support element in particular, also assumes the function of a spacer, providing mechanical stability.

Finally, the mouthpiece materials must meet the economic target. In particular, there is a need for suitable mouthpiece materials adapted to be produced with the least possible use of material and with the lowest possible processing cost.

While traditional cigarette filters, which are typically made from cellulose acetate filamentary fibers, provide minimal filtration of constituents in the smoke, these filter materials can often only be used to a limited extent in other applications, particularly in the case of HNB products or electronic cigarettes, because In such applications, the filter materials, or respectively the mouthpiece materials, must take on other functions.

HNB products, as well as conventional smoking products, generally have the disadvantage that the user absorbs the high temperature inhaled aerosol. This is sometimes annoying for the user. Particularly with HNB products, the mouthpiece materials thus have the task of cooling the aerosol with the lowest possible filtration performance.

And also in the case of traditional cigarettes, in particular the so-called thin or ultra-thin cigarettes; i.e., for small diameter cigarettes, e.g. 5.0-6.5 mm, the filter materials/mouthpiece materials should provide - compared to filter materials for very long cigarettes - reduced filtration performance, increased cooling and improved tactile properties (hard but not too hard to grip). Naturally, there is less smoke/flavor during combustion compared to a very long cigarette. A low filtration performance is achieved so as not to further reduce the aroma. If only the amount of filter material is reduced for this purpose, the hardness of the filter will eventually become insufficient.

For the same fiber density, filters for thin or ultra-thin cigarettes also have a significantly higher draw resistance compared to very long filters, which is generally undesirable.

For HNB products, as well as for ultra-fine cigarettes, increasing fiber linear density while maintaining overall linear density has been proposed in order to achieve the desired reduced filtration performance in terms of consumable components such as resin, as well as sufficient hardness. filter. Furthermore, this approach has the disadvantage of such high linear density filter fiber materials having economic disadvantages on conventional spinning machines. In the production of a traditional filter tow, a solution of approximately 30% cellulose-2,5-aceate in acetone is forced through the spinning machines, the acetone is evaporated in the spinning shaft by forcing heated air on it, a plurality of fiber filaments (1000-35000) are then collected into a tape and crimped into stuffed block. In the case of higher fiber densities, a larger volume of solvent must be evaporated for each filamentary fiber, which, due to the larger ratio of fiber cross-sectional area to fiber surface area, takes longer and results in lower spinning speeds.

Based on this problem, the present invention is based on the problem of accurately determining the material suitable for a wide range of applications of a smoking article.

In particular, the present invention is based on the problem of accurately defining a filter material having low draft resistance and low filtration performance, whereby the filter material is capable of achieving a substantially sufficiently high Filtron hardness that is as constant as possible when used in smoking articles. , and the filter material can nevertheless be produced particularly economically.

The filter material must furthermore be suitable to obtain a filter having a uniform, white and flat front end on the side of the mouth.

It is further preferred in this context that the filter material exhibit a selective phenol filtering effect.

The filter material must in particular be suitable for reliably cooling the heated particle-laden gas so as to be able to lower the temperature of the gas, aerosol or vapor absorbed by the user from the smoking article.

The material must also be suitable, so that when used as a filter material, in particular for thin or ultra-thin cigarettes, a controlled draw resistance, and which is reduced in particular compared to very long filters, can be realized.

These and other tasks are solved by the subject matter of the independent claim 1 of the claims.

Accordingly, the invention relates in particular to a material for forming a mouthpiece for smoking articles, whereby the material comprises a filter material based on cellulose acetate filiform fibers which are at least partially formed as hollow cellulose acetate filiform fibers. The fill material, shaped in part as hollow cellulose acetate filamentary fibers, has a lower density and a higher filling value than conventional cellulose acetate fibers, which do not have a hollow structure and are typically used in cigarette filters. The provision of such filler material makes it possible to significantly increase the performance that can be achieved with the mouthpiece and the range of applications.

The term "hollow fiber" as used herein is particularly to be understood as preferably a cylindrical fiber having one or more continuous hollow spaces in cross section. The hollow fibers are preferably at least partially crimped. However, the invention is not limited to crimped hollow fibers, but instead also relates to non-crimped fibers or their use, respectively.

According to embodiments of the present invention, the hollow fibers are at least partially implemented as multi-cavity hollow fibers. Compared to single-cavity hollow fibers, multi-cavity hollow fibers are significantly more resistant to twisting, with the result that very high Filtron hardness can be achieved without increasing material compression.

The term "Filtron hardness" when used herein should be understood as the filter hardness as determined according to the Filtron principle. This principle refers to the determination of filter hardness by vertically pressing the flat front end of a 12 mm diameter cylindrical rod onto a horizontally positioned filter rod with a load of 300 g. .

According to preferred embodiments of the present invention, the hollow shaped cellulose acetate filamentous fibers appear to be at least partially trilobed; i.e., three-arm, star-shaped cross section. Such a cross-sectional shape is well suited when the cellulose acetate fibers are to have the highest possible specific surface area in order to allow for example a high filtration capacity together with the simultaneous economical use of raw materials. Alternatively, it is possible to obtain the desired high specific surface area with a bundle of very fine fibers with a circular cross section. However, other cross-sectional shapes for hollow cellulose acetate fibers are also possible, such as, for example, a four-sided cross-sectional shape.

The filter material and/or fill material of the present invention is economical to produce and can be processed alone or together with conventional non-hollow cellulose acetate fibers into a filter rod having suitable draft resistance and optimized filtration properties.

Since the filter and/or fill material according to the invention comprises a fill material based on cellulose acetate filamentary fibers which exist at least partially in the form of hollow cellulose acetate filamentary fibers, low draft resistance and low filtration performance can be realized since the filamentary the fibers of the filter material and/or filler of the at least partially hollow form of the cellulose acetate fiber have a small outer surface area relative to the total fiber volume. It is preferred here that the fibers of the filter material and/or the fill material of the at least partially hollow form of the cellulose acetate fiber show as round a cross-section as possible.

In this context, the ability to realize very high Filtron hardness has surprisingly been found with filter material and/or fill material due to fibers having an at least partially hollow form of cellulose acetate fiber. In fact, filters that are at least partially formed from hollow cellulose acetate filamentous fibers (hollow fibers) have been found to achieve the desired minimum Filtron hardness at a lower fiber weight per unit volume.

Due to being based on cellulose acetate fibers, the inventive filter material and/or fill material is suitable for obtaining a filter having a uniform, white and flat front end on the side of the mouth, whereby the effect of selective filtration of phenol can further also be realized.

From the point of view of the dialogue about smoking and health, the use of a filter material and/or a filler based on cellulose acetate fibers, first of all, makes it possible to obtain filter rods, in particular for cigarettes, which have obviously excellent properties with respect to the phenomenon of moisture absorption. A cellulose acetate-derived filter thus filters harmful nitrosamines and phenols much more effectively than condensate and nicotine. In addition, today's traditional tobacco blends such as "American Blend", "German Blend" and "Virginia" are rated by smokers as most palatable when combined with a cellulose acetate filter rod. Another advantage of the cellulose acetate filter rod, which should not be underestimated, can be found in the optical uniformity of the filter cut surfaces.

By means of the inventive filter material and/or fill material at least partially formed from hollow cellulose acetate fibers serving as filler, there can be a wide range of varying draft resistance and filtration characteristics in filter rods made from the inventive material.

In particular, it has been shown that a filter material composed at least in part of hollow cellulose acetate fibers exhibits an improved thermal cooling effect. It was found that the use of hollow cellulose acetate fibers as filler material was still able to achieve a very low filtration effect; i.e., the retention effect, for suspended solids and gases to be removed. This effect is supposed to be achieved by the surface or flow of the gas or air to be cleaned being modified by the hollow cellulose acetate fibers so as to retain only a small amount of any potentially suspended matter in the gas/air. Another reason may be that the use of hollow cellulose acetate fibers can achieve a different, particularly useful surface structure of the filter material.

The inventive filter material and/or fill material further has the advantage of allowing, in particular, controlled cooling of heated particle-laden gas (in particular aerosols), so that the temperature of the gas, aerosol or vapor ingested by the user of the smoking article or HNB article can be reduced on purpose. By varying the proportion of hollow cellulose acetate fibers in the filter and/or media material, the desired cooling effect can thus be tailored specifically to the application.

It is additionally important to note that in the filter material and/or fill material of the invention, the flow exists mainly around and less through the hollow cellulose acetate filamentous fibers (=hollow fibers). From geometrical considerations, it is obvious that the distances between the fibers are thus significantly larger compared to the cavity (hollow section) of the hollow fiber. The viscosity of the aerosol (essentially air) then causes it to follow the path of least resistance (ie, flow between the fibers rather than through each individual fiber).

In other words, the operative filtration surface is in no way maximized in the inventive filter and/or fill material, since there is no flow through the hollow cellulose acetate fibers in the filter and/or fill material.

In particular, the hollow cellulose acetate fibers may thus have kinks that close the lumen of the hollow cellulose acetate fibers without affecting the performance of the filter and/or media inventive material with respect to predetermined target parameters.

In particular, it should be noted in this context that hollow cellulose acetate fibers designed as hollow fibers need not be continuously hollow, but rather may also be partially closed by kinks. They may also deviate from the ideal round shape.

Embodiments of the invention provide hollow cellulose acetate fibers of filter material and/or filler material to serve on the one hand as a support material and on the other hand as a cooling material. By means of hollow cellulose acetate fibers, which simultaneously serve as support material, particularly compact mouthpieces can be realized, which thus do not entail an increase in the dimensions of the smoking article.

For example, it is possible for the filter material and/or the fill material to show an abutment of the areas of hollow cellulose acetate fibers and non-hollow cellulose acetate fibers in the longitudinal direction of the mouthpiece. A mixture of hollow and non-hollow cellulose acetate fibers would also be possible. Alternatively, or in addition, the hollow and non-hollow cellulose acetate fibers can be layered and then crimped. This allows the largest possible area of hollow cellulose acetate fibers to serve as a cooling material, resulting in better cooling of the particle-laden gas.

The filter material and/or the filler material can be introduced into the smoking article in such a way that the hollow cellulose acetate fibers, in particular, are positioned substantially longitudinally with respect to the direction of flow of the particle-laden gas or aerosol. This can thus ensure that the filter and/or fill material only causes a reduced pressure drop when the user draws on the mouthpiece, so that the user does not perceive the suction action as difficult or unpleasant. By changing the alignment of the hollow cellulose acetate fibers with respect to the direction of flow of the particle-laden gas or aerosol, the drag resistance of the filter material and/or the fill material can be varied over a wide range and adapted to the respective application.

Changing the proportion of hollow and non-hollow cellulose acetate fibers in the filter and/or media material and/or changing the alignment of the hollow and non-hollow cellulose acetate fibers with respect to the flow direction of the particle-laden gas or aerosol in the filter and/or media material provides the possibility of not only adjusting the cooling performance and filtration, but also the drag resistance of the filter material and/or the fill material.

Alternatively, it is envisaged that the material of the filter and/or the filler consists of only hollow cellulose acetate fibers. The filter and/or media material then corresponds to an optimum cooling efficiency with reduced filtration performance.

A further embodiment of the inventive filter material and/or filter material provides for the filter and/or media material to be placed as a separate area in front of the mouthpiece in the direction of flow of the particle laden gas or aerosol. A single section can take many forms. While the cylindrical shape is described as a preferred example, the invention should not be limited to this. Conventional smoking articles typically have a substantially cylindrical design. The individual section can thus additionally be positioned before any possible filter in the direction of flow of the particle-laden gas. The filter and/or fill material serving as a cooling device and formed as a separate section may, for example, consist entirely of hollow cellulose acetate fibers.

It is also possible for a separate section to contain a wrapper made of, for example, paper or a type of casing, so that hollow cellulose acetate fibers serving as a cooling material can be encapsulated. The wrapper or casing respectively has an inlet and an outlet for the particle-laden gas/aerosol through which it flows due to the suction action generated by the user's mouthpiece. The hollow cellulose acetate fibers serving as the cooling material may optionally also be attached to or on the smoking article, for example in encapsulated form. Thus, the user has the option of only cooling the particle-laden gas when the user deems it necessary to do so.

As already stated, in particular, the drag resistance of a filter rod formed from the inventive filter material can be varied over a much larger range by varying the proportion of hollow cellulose acetate fibers in the filter material.

So, in this way, it can be stated that with a filter material that is at least partially composed of hollow cellulose acetate fibers, there is a wide range in which the draft resistance and filtration performance can be adapted to the respective requirements, and this is clearly more flexible than is the case with conventional cellulose acetate filter materials. The cooling effect can also be variably controlled.

The present invention, in particular, makes it possible to form mouthpieces or filters, respectively, from cellulose acetate, which usually exists in the form of a strand of substantially longitudinal continuous filamentary fibers, the continuous fibers being preferably crimped so that short sections of individual fibers are unevenly placed in non-parallel, converging and divergent directions compared to the predominantly longitudinal direction of the strand.

In one possible embodiment of the filter material according to the invention, the surface structure of the filter material can be modified with highly crimped cellulose acetate fibers. The crimp index of the cellulose acetate fibers is preferably between 10% and 60%, and in particular between 20% and 50%.

The crimp index Ix is a measure of the intensity of the crimp. The crimp index of the filter tow is determined by a tensile test (force/tension ratio). It is defined as the ratio of the total length L2 under test load minus the original length to the original length under preload L1:

The test load is 25 N and the preload is 2.5 N. The clamping length is 250 mm. The crimp index is determined in a tensile test at a constant tension speed of 300 mm/min on a G02 device from Borgwaldt GmbH in Hamburg. Ten individual measurement values are recorded for each measurement. The test is performed in a typical climate at 20ºC with 60% relative humidity.

The inventive filter material preferably exists in the form of a filter tow consisting of continuous cellulose acetate fibres, in particular cellulose 2,5 acetate fibres, which have been crimped in a packing device. To obtain a filter tow, a solution of approximately 30% cellulose-2,5-aceate in acetone is forced through the spinning machines, the acetone is evaporated in the spinning shaft by forcing heated air on it, a lot of filamentous fibers (1000-35000) are then collected into a tape and crimped in a stuffed device. The product is then dried, filled into storage containers and finally pressed into 300 and 600 kg bales.

For spinning the dope, spinning machines are used to spin hollow cellulose acetate filamentary fibers and/or cellulose acetate staple fibers.

After the filter tow bales have been transported to the filter or cigarette manufacturer, the filter tow is removed from the bales and processed into filter rods in a filter rod machine as described in printed publication US 5,460,590 A, for example. The filter tow is thus stretched in the stretching device, supplied with an additive to bind the filamentous fibers, and then, after forming a three-dimensional bundle, is fed into the formatting unit through the inlet funnel, where it is compressed along the transverse axis, wrapped in paper and cut to the final filter rod lengths.

The additive used to bind the fibers may be a high boiling solvent for cellulose acetate, such as glycerol triacetate (triacetin), for example, which renders the surface of the fibers transiently soluble after application. Wherever two filiform fibers happen to touch, a permanent bonding point occurs some time later when the excess additive moves into the interior of the fiber surface, causing the previously liquid droplets of the solution to solidify. Due to the aforementioned movement of the curing agent, mechanically strong, three-dimensionally cross-linked filter rods are obtained after a storage period of less than an hour, said filter rods are also called "space filters" and have a low packing density typically 20 mg/ml to 90 mg/ml, preferably 30-70 mg/ml, and more preferably 40-60 mg/ml. Because of their hardness, these filter rods can be processed on modern cigarette machines at high speeds without difficulty.

Tests have shown that the use of hollow cellulose acetate filamentous fibers in the filter material can reduce the filtration performance of spatial filters while maintaining specifications such as length, diameter, traction resistance and fiber linear density and increasing cooling efficiency.

By correspondingly increasing the proportion of hollow fibers (hollow-shaped cellulose acetate filamentous fibers) in the filter material, the draft resistance can be maintained in a desired low range without increasing the linear density of the filamentous fiber despite an increase in cooling efficiency and a decrease in filtration performance.

According to implementations of the inventive filter material, it is thus specifically provided that the percentage of hollow-shaped (hollow) cellulose acetate filamentous fibers in the filter material is between 20-100%, and preferably between 40-100%, and more preferably in depending on the application - between 70-100%.

In particular, the hollow area in the filter material is preferably 25-90% and preferably 50-80%. This hollow section makes a decisive contribution to the filtration performance on the one hand and to the reduction of the draft resistance on the other, which is only possible due to the appropriate proportion of hollow fibers in the filter material, but cannot be realized with closed threadlike fibers. The hollow section thus corresponds to the ratio of the "hollow" area of the filter material to the "total" cross-sectional area of the fibers.

It should be noted in this context that the inventive filter material is also, in particular, characterized by a yarn diameter of cellulose acetate filiform fibers which is significantly larger than that of other (synthetic) hollow fibers having yarn diameters in the range between 10 and 30 µm. In contrast, the thread diameter of the hollow cellulose acetate filamentary fibers is in the range between 30-150 µm (outer diameter), and preferably between 50-120 µm (outer diameter), and more preferably between 60-100 µm (outer diameter) . The hollow section can thus be enlarged and thus the specific filtration performance of the invented filter material and/or fill material is significantly reduced, while at the same time the cooling efficiency of the invented filter material and/or fill material is increased.

The invention further relates to a cigarette filter made from a filter material of the type mentioned above.

In non-limiting embodiments, either a thermoplastic cellulose ether fiber material or, in the case of a non-thermoplastic cellulose ether, a water-soluble adhesive can be used to form the filter of the invention. In the first case, the fiber material is thermoplastic cellulose ether, a distinction can be made between the two cases. In the first case, the fiber material is made from natural thermoplastic cellulose ether, such as, for example, cellulose acetate butyrate. Additional measures are not needed here for the processing of the filter tow into the invented filters. With a non-thermoplastic based polymer such as cellulose-2,5-acetate, for example, it must be thermoplasticized by adding a suitable plasticizer.

To create the inventive filter, the filter tow is pulled from the bale, expanded pneumatically, and stretched in a manner traditional for space filters.

In the context of the teachings of the invention, the weight of acetate can be a maximum of 5 mg per mm of filter length and at least about 2 mg per mm of filter length, and in particular about 3-4 mg per mm of filter length. If the maximum value of 5 mg per mm of filter length is exceeded, such a product will then not be adequately economical. Preferably, a minimum value of about 2 mg per mm of filter length is maintained. According to the prior art, failure to achieve this value results in no further ability to maintain the desired minimum 88% hardness of the cigarette filter.

In the context of the teachings of the invention, the draft resistance can be a maximum of 2 mm decapa per mm filter length and at least about 0.1 decapa per mm filter length, and in particular 0.2 decapa to 1 decapa per mm filter length. A draft resistance of 0.3-0.7 decapa per mm of filter length is particularly preferred. A minimum value of 0.3 decaPa per mm of filter length is preferably maintained. According to the prior art, failure to achieve this value results in no further ability to maintain the desired minimum 88% hardness of the cigarette filter.

Several aspects essential to the invention are summarized below:

According to a first aspect, the invention relates to a filter material and/or filler material for mouthpieces for use with smoking articles or HNB products, wherein the filter and/or filler material is filamentary fibers based on cellulose acetate, which are at least partially formed as hollow and/or tubular cellulose acetate filiform fibers.

According to one embodiment of the filter material and/or the filler material, the cellulose acetate filament fibers comprise hollow and in particular crimped continuous cellulose acetate filament fibers and/or hollow and in particular crimped and cut continuous cellulose acetate filament fibers.

According to one embodiment of the filter material and/or the fill material, the crimp index of the cellulose acetate fibers is between 10% and 60%, in particular between 20% and 50%.

According to one embodiment of the filter material and/or the filler material, the cellulose acetate filamentary fibers are formed from a thermoplastic cellulose material, wherein the cellulose acetate fibers contain the same uniform distribution, provided that a plasticizer is included in the composition, and/or in in which a water-soluble adhesive is present on the surface of the cellulose acetate fibers.

According to one embodiment of the filter material and/or filler material, when a plasticizer is used, the content of the plasticizer is between 1% and 40%.

According to one embodiment of the filter material and/or filler material, when the plasticizer is used, it is triacetin, triethylene glycol diacetate and/or citric acid diethyl ester.

According to one embodiment of the filter material and/or fill material, the cellulose acetate filiform fibers have a fineness between 5 and 30 denier, preferably between 10 and 25 denier, and more preferably between 15-20 denier.

According to one embodiment of the filter material and/or fill material, the combined linear density of the filter material and/or fill material is between 4,000 and 40,000 denier, and preferably between 6,000 and 30,000 denier.

According to one embodiment of the filter material and/or fill material, the hollow section in the filter material and/or fill material - with respect to the section orthogonal to the fibers of the filter material and/or fill material - is 25-90%, and preferably 50-80%.

According to one embodiment of the filter and/or media material, the threadlike fiber diameter of the cellulose acetate fibers is in the range between 30-150 µm (outer diameter) and preferably between 50-120 µm (outer diameter) and more preferably between 60-100 µm (outside diameter).

According to one embodiment of the filter material and/or filler material, the mass fraction of hollow cellulose acetate filamentous fibers is between 20-100%, preferably 50-100%, and more preferably 70-100%.

According to one embodiment of the filter material and/or the fill material, the hollow cellulose acetate filamentary fibers are mutually spaced apart in an uneven pattern, whereby the cellulose acetate fibers cross-link, and as a result, the connecting cellulose acetate fibers intertwined and/or entangled with each other.

According to one embodiment of the filter material and/or filler material, a binder, in particular an organic or inorganic binder, is additionally provided to bind the cellulose acetate fibers.

According to a further aspect, the present invention relates to a mouthpiece for use with smoking articles or HNB articles, wherein the mouthpiece comprises a filter material and/or filler material of the aforementioned inventive type.

According to a further aspect, the present invention relates to a cigarette filter or cigarette filter element having a filter material and/or filler material of the above-mentioned inventive type.

According to embodiments of the cigarette filter or cigarette filter element, respectively, at least one feature among the following features is implemented:

- the fiber density of the filter material and/or the filler material is between 10-70 kg/m ³ and preferably between 20-70 kg/m ³ and more preferably between 40-60 kg/m ³ ;

the cigarette filter or cigarette filter element has a Filtron hardness of at least 88%, and preferably 88-95%, and more preferably a Filtron hardness of 90-93%;

- the cigarette filter or cigarette filter element has a draft resistance of at least 0.1 decapa per mm of filter length, and preferably a draft resistance of 0.2-1.0 decapa per mm of filter length, and more preferably a draft resistance of 0.3- 0.7 decapa per mm of filter length;

- the filter material and/or the filler material contains a plasticizer, while the content of the plasticizer is between 1-40%.

According to embodiments of the cigarette filter/cigarette filter element, in particular, the flavor release element in the form of a capsule or capsule type is further incorporated into the filter material and/or the fill material.

According to embodiments of the cigarette filter/cigarette filter element, in addition to hollow cellulose acetate fibers, the cigarette filter or cigarette filter element, respectively, also comprises solid cellulose acetate filiform fibers.

In a further aspect, the present invention relates to the use of the inventive filter and/or fill material in smoking articles or HNB articles.

According to a further aspect, the present invention relates to a method for producing a filter material and/or a fill material for mouthpieces for use in smoking articles or HNB products, wherein the filter material and/or fill material preferably consists of cellulose acetate filamentary fibers and/or cellulose acetate staple fibers, wherein a solution of cellulose acetate having an acetyl number of at least 53% in acetone is forced through a spinning machine having a plurality of holes, and, as a result, cellulose acetate filamentous fibers are subsequently cut into acetate- cellulosic staple fibers if necessary, and whereby the plurality of cellulosic acetate filamentous fibers and/or cellulose acetate staple fibers thus obtained are collected into a filter tow, which potentially wriggles depending on the requirements applied, with the spinning machine, through which the cellulose acetate solution is pressed is designed so that the hollow cellulose acetate filiform fibers are twisted.

Claims (45)

1. A process for preparing a filter material and/or a mouthpiece filler material for use in smoking articles or non-combustion heating articles (HNB articles) consisting of cellulose acetate filamentary fibers and/or cellulose acetate staple fibers, wherein the solution cellulose acetate having an acetyl value of at least 53% in acetone is forced through a spinner having a plurality of holes, and the cellulose acetate filamentous fibers are then cut into cellulose acetate staple fibers, if necessary, and the plurality of acetate- the cellulose filamentary fibers and/or cellulose acetate staple fibers thus obtained are assembled into a filter tow, optionally crimped depending on the requirements to be applied, the spinning machine through which the cellulose acetate solution is pressed is configured so that the hollow cellulose acetate fibers twisted, while the hollow section in the filter and/or filler material - in relation to the cross section orthogonal to the fibers of the filter and/or filler material - is 25-90%, and preferably 50-80%, and at the same time, the thread diameter of the cellulose acetate filamentary fibers is in the range between 60-100 µm. 2. The method according to claim 1, the crimp value of the cellulose acetate fibers is between 10% and 60%, in particular between 20% and 50%. 3. The method according to claim 1 or 2, while the acetate-cellulose filamentary fibers contain a plasticizer in a uniform distribution; and/or wherein the water-soluble adhesive is present on the surface of the cellulose acetate filiform fibers. 4. The method according to one of paragraphs. 1-3, wherein the cellulose acetate filamentary fibers and/or cellulose acetate staple fibers contain a plasticizer, and the content of the plasticizer is between 1% and 40%. 5. The method according to one of paragraphs. 1-4, wherein the cellulose acetate filamentous fibers and/or the cellulose acetate staple fibers contain a plasticizer, and the plasticizer is triacetin, triethylene glycol diacetate and/or citric acid diethyl ester. 6. The method according to one of paragraphs. 1-5, wherein the cellulose acetate fibers have a fineness between 5 and 30 denier, preferably between 10 and 25 denier, and more preferably between 15-20 denier. 7. The method according to one of paragraphs. 1-6, while the total linear density of the filter material and/or filler is between 4000 and 40000 denier, and preferably between 6000 and 30000 denier. 8. The method according to one of paragraphs. 1-7, wherein the mass fraction of hollow cellulose acetate fibers is between 20-100%, preferably 50-100%, and more preferably 70-100%. 9. The method according to one of paragraphs. 1-8, wherein the hollow cellulose acetate fibers are mutually spaced apart in an uneven pattern, and the cellulose acetate fibers are cross-linked, whereby the connecting cellulose acetate fibers are woven and/or entangled with each other. 10. The method according to one of paragraphs. 1-9, wherein a binder, in particular an organic or inorganic binder, is additionally provided for binding the cellulose acetate fibers. 11. A mouthpiece for use with smoking articles or HNB products, wherein the mouthpiece contains a filter material and/or filler material obtained in accordance with the method according to paragraphs. 1-10. 12. Mouthpiece according to item 11, wherein the fiber density of the filter material and/or the filler material is between 10-70 kg/m ³ , and preferably between 20-70 kg/m ³ , and more preferably between 40-60 kg/m ³ ; and/or wherein the cigarette filter or cigarette filter element has a Filtron hardness of at least 88%, and preferably 88-95%, and more preferably a Filtron hardness of 90-93%; and/or wherein the cigarette filter or cigarette filter element has a draft resistance of at least 0.1 daPa per mm of filter length, and preferably a draft resistance of 0.2-1.0 daPa per mm of filter length, and more preferably a draft resistance of 0.3 -0.7 daPa per mm of filter length. 13. Mouthpiece according to item 11 or 12, wherein, in particular, an aroma release element in the form of a capsule or in the form of a capsule is additionally included in the filter and/or fill material. 14. The mouthpiece according to one of paragraphs. 11-13, wherein the filter material and/or filler material further comprises solid cellulose acetate fibers in addition to hollow cellulose acetate fibers. 15. Cigarette filter containing filter material and/or filler material obtained in accordance with the method according to paragraphs. 1-10. 16. Cigarette filter according to claim 15, wherein the fiber density of the filter material and/or the filler material is between 10-70 kg/m ³ , and preferably between 20-70 kg/m ³ , and more preferably between 40-60 kg/m ³ ; and/or wherein the cigarette filter has a Filtron hardness of at least 88%, and preferably 88-95%, and more preferably a Filtron hardness of 90-93%; and/or wherein the cigarette filter has a draft resistance of at least 0.1 daPa per mm of filter length, and preferably a draft resistance of 0.2-1.0 daPa per mm of filter length, and more preferably a draft resistance of 0.3-0.7 daPa per mm filter length. 17. Cigarette filter according to item 15 or 16, wherein, in particular, an aroma release element in the form of a capsule or in the form of a capsule is additionally included in the filter and/or fill material. 18. Cigarette filter according to one of paragraphs. 15-17, wherein the cigarette filter further comprises solid cellulose acetate fibers in addition to hollow cellulose acetate fibers. 19. The cigarette filter element containing the filter material and/or filler material obtained in accordance with the method according to paragraphs. 1-10. 20. Cigarette filter element according to claim 19, wherein the fiber density of the filter material and/or the filler material is between 10-70 kg/m ³ , and preferably between 20-70 kg/m ³ , and more preferably between 40-60 kg/m ³ ; and/or wherein the cigarette filter element has a Filtron hardness of at least 88%, and preferably 88-95%, and more preferably a Filtron hardness of 90-93%; and/or wherein the cigarette filter element has a draft resistance of at least 0.1 daPa per mm of filter length, and preferably a draft resistance of 0.2-1.0 daPa per mm of filter length, and more preferably a draft resistance of 0.3-0, 7 daPa per mm filter length. 21. Cigarette filter element according to claim 19 or 20, wherein, in particular, an aroma release element in the form of a capsule or in the form of a capsule is additionally included in the filter and/or fill material. 22. The cigarette filter element according to one of paragraphs. 19-21, wherein the cigarette filter element further comprises solid cellulose acetate fibers in addition to hollow cellulose acetate fibers.