Tobacco filter comprising lyocell tow

Abstract

Provided is a cigarette filter comprising a lyocell tow comprising a plurality of lyocell fibers and a binder for binding the lyocell fibers to each other, wherein the cigarette filter has a hardness of 85% or more.SOLUTION: The cigarette filter may have a hardness of 80% or more even 5 minutes after injecting 20 parts by weight to 25 parts by weight of water based on 100 parts by weight of the lyocell tow. The cigarette filter has a moisture disintegration degree of 7% or less. The cigarette filter overcomes the material problems of the conventional lyocell tow, and has high hardness and low moisture disintegration.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cigarette filter comprising lyocell tow. Specifically, the present invention relates to a cigarette filter comprising lyocell tow made of a plurality of lyocell fibers and a binder that binds the lyocell fibers together, and having an excellent hardness of 85% or more.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0173488, filed December 7, 2021, and incorporates all of the contents disclosed in the documents of that Korean patent application as part of this specification. [Background technology]

[0003] Generally, to manufacture cigarettes, various types of leaf tobacco are first blended and processed to achieve the desired aroma and flavor. The processed leaf tobacco is then shredded to produce cut tobacco leaves, which are then wrapped in cigarette paper to produce filterless cigarettes. If necessary, a filter is then attached to the filterless cigarette.

[0004] Cigarette paper can be made from flax, wood pulp, etc., and is required to maintain the combustion properties and tobacco flavor during combustion. The cigarette filter may contain activated carbon, flavoring substances, etc., and may consist of a mono-filter or multiple filters, and is wrapped in cigarette filter wrapping paper. The tobacco shreds and the cigarette filter are connected by tipping paper, and the tipping paper may contain fine holes.

[0005] Conventional cigarette filters use cellulose acetate tow, which is made by extracting and acetylating cellulose from wood pulp. Recently, however, environmentally friendly alternative materials have been developed to protect the natural environment and reduce costs. For example, tow made from lyocell fiber, which is made by fiberizing cellulose itself, is being developed, unlike cellulose acetate. Hardness of cigarette filters is an important indicator related to consumer needs and the workability of cigarette manufacturing. Cigarette filters made from tow, a bundle of fiber strands, are not suitable due to their low hardness. Therefore, in order to be used in cigarette filters, the hardness must be increased to a certain level. For example, methods for increasing filter hardness include using a hardener or a plasticizer. The hardener method uses a binder-like substance to bond fiber strands together, imparting hardness to the filter and making it stronger. The plasticizer method uses a specific substance to partially dissolve or plasticize the fibers themselves, forming junctions between the fibers, and then plasticizing the resulting mixture.

[0006] Conventional cellulose acetate uses plasticizers (triacetin, triethyl citrate) to partially dissolve the fiber strands, which then hardens the fiber strands, giving the cigarette filter hardness. However, since there are currently no plasticizers available for lyocell fiber, it is essential to develop a hardness enhancer that is suitable for lyocell fiber.

[0007] Unlike hydrophobic cellulose acetate, the lyocell fiber is known to be a hydrophilic material. Therefore, even if the lyocell fiber is applied to a cigarette filter after increasing its hardness with a hardness enhancer, it is important to consider that the structure of the filter will not be destroyed by moisture supplied by the smoker during smoking.

[0008] The present inventors recognized the technical problems with the above-mentioned lyocell fiber material and completed the present invention after continuous research into lyocell tow with excellent functionality suitable for use in cigarette filters. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 10-2015-0035800 Summary of the Invention [Problem to be solved by the invention]

[0010] To provide a cigarette filter that can solve the material problems inherent in lyocell tow, such as hardness and water disintegration, in a cigarette filter containing lyocell tow as an environmentally friendly material. [Means for solving the problem]

[0011] According to a first aspect of the present invention, The present invention provides a cigarette filter comprising a lyocell tow made of a plurality of lyocell fibers and a binder that binds the lyocell fibers together, and having a hardness of 85% or more.

[0012] In one embodiment of the present invention, the cigarette filter has a hardness of 80% or more even 5 minutes after 20 to 25 parts by weight of water, based on 100 parts by weight of lyocell tow, is poured thereinto.

[0013] In one embodiment of the present invention, the cigarette filter has a moisture disintegration rate of 7% or less.

[0014] In one embodiment of the present invention, the binder comprises a polyester.

[0015] In one embodiment of the present invention, the polyester is a copolymer of an aromatic monomer and an aliphatic monomer.

[0016] In one embodiment of the present invention, the polyester has a viscosity of less than 5 cps at 40° C. for a 15% by weight aqueous solution of the polyester.

[0017] In one embodiment of the present invention, the aromatic monomer is a dicarboxylic acid having a C5 to C12 arylene or heteroarylene group.

[0018] In one embodiment of the present invention, the aliphatic monomer is a diol having a C1 to C4 alkylene group, a dicarboxylic acid having a C2 to C12 alkylene group, or a combination thereof.

[0019] In one embodiment of the present invention, the polyester is contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of lyocell tow.

[0020] In one embodiment of the present invention, the binder further comprises hydroxypropylmethylcellulose or polyvinylpyrrolidone.

[0021] In one embodiment of the present invention, the weight ratio of polyester to hydroxypropylmethylcellulose or polyvinylpyrrolidone in the binder is 1:1 to 1:3. [Effects of the Invention]

[0022] A cigarette filter according to one embodiment of the present invention contains lyocell tow, an environmentally friendly material, while overcoming the material problems that conventional lyocell tow has, and has an excellent hardness of 90% or more.

[0023] In addition, the cigarette filter has suitable durability against moisture, minimizes the change in hardness to 6% or less while the smoker is smoking, and maintains an excellent hardness of 85% or more until the smoker finishes smoking and the smoking article leaves the smoker's hand. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a diagram showing a schematic configuration of a smoking article according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, specific examples will be described in detail with reference to the illustrative drawings. When assigning reference numerals to components in each drawing, it should be noted that the same components are assigned the same numerals as much as possible even if they appear in different drawings. Furthermore, when describing specific examples, if it is determined that a detailed description of related publicly known configurations or functions would hinder understanding of the specific examples, the detailed description will be omitted.

[0026] Furthermore, when describing components of specific examples, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are used to distinguish the component from other components, and do not limit the nature, order, or sequence of the components. When a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that other components may also be "coupled," "coupled," or "connected" between each component.

[0027] Components that have a common function with components included in one specific example will be described using the same names in other specific examples. Unless otherwise specified, the description of one specific example may also be applied to other examples, and detailed descriptions will be omitted to the extent that they overlap.

[0028] As used herein, the term "smoking article" may refer to an article capable of generating aerosol, such as tobacco (cigarette), cigar, etc. Smoking articles may include an aerosol-generating substance or an aerosol-forming substrate. Smoking articles may also include solid substances based on tobacco raw materials, such as flat tobacco, shredded tobacco, or reconstituted tobacco. Smoking substances may also include volatile compounds. The smoking article may include several segments each with their own functionality, and such segments are represented by "... segments." As used herein, smoking articles may refer not only to combustible cigarettes, but also to heated cigarettes used with an aerosol-generating device (not shown), such as electronic cigarette devices.

[0029] In this specification, the terms "upstream" and "downstream" are used to indicate the relative positions of segments constituting a smoking article with respect to the direction in which a user draws air using the smoking article. A smoking article includes an upstream end (i.e., the portion from which air enters) and an opposing downstream end (i.e., the portion from which air exits). When using a smoking article, a user can bite the downstream end of the smoking article. The downstream end is located downstream of the upstream end, and the term "end" may also be described as "terminal end."

[0030] The present invention relates to a cigarette filter applicable to smoking articles. According to one embodiment of the present invention, the cigarette filter includes a lyocell tow made of a plurality of lyocell fibers and a binder binding the lyocell fibers together. The lyocell fiber is an environmentally friendly fiber made from cellulose extracted from wood pulp. The lyocell tow refers to a bundle formed by cross-linking adjacent lyocell fibers. According to one embodiment of the present invention, the lyocell fiber may have a fineness of 1.0 denier to 12.0 denier. According to another embodiment of the present invention, the lyocell fiber bundle constituting the lyocell tow may have a fineness of 15,000 denier to 45,000 denier. A binder suitable for the lyocell fiber is mixed with a solvent to prepare a binder solution, which is then sprayed onto the lyocell tow and dried, allowing the lyocell tow to form a structure having a certain level of hardness or greater.

[0031] A cigarette filter containing lyocell tow according to one embodiment of the present invention has excellent hardness due to the binder binding and also has excellent moisture resistance. According to one embodiment of the present invention, the cigarette filter has a hardness of 85% or more. Specifically, the hardness of the cigarette filter may be 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, or 91.5% or more. The hardness of the cigarette filter is a numerical value that represents the degree to which the diameter of the cigarette filter is maintained when the cigarette filter is pressed with a certain level of vertical force, and can be calculated using the following equation 1:

[0032] [Formula 1] Filter hardness (%) = [Da] / D x 100

[0033] Here, D is the filter diameter (mm), and a is the distance (mm) that a 300 g weight moves down (pressing the filter). The measurements required to calculate the hardness of the cigarette filter can be obtained using a device commonly used in the art, such as Filtrona's DHT 200.TM can be used. The force applied when measuring hardness takes into consideration the force actually applied when a smoker holds a cigarette. A hardness value of 85% or more obtained through a cigarette filter according to one embodiment of the present invention is technically significant in that it ensures a hardness level that can replace cigarette filters made of conventional cellulose acetate using lyocell tow, an environmentally friendly material.

[0034] The above-mentioned cigarette filter hardness indicates the hardness when a smoker first holds a cigarette to smoke, but this hardness does not guarantee that the cigarette filter will maintain its hardness until the smoker finishes smoking. When a smoker smokes, a considerable amount of moisture can flow into the cigarette filter. In this case, if a filter containing lyocell tow has a certain level of moisture resistance, it is easy to maintain its initial hardness. Unlike hydrophobic cellulose acetate, lyocell fiber is known to be a hydrophilic material, and therefore, due to the characteristics of the material, it is difficult to maintain its hardness. According to one embodiment of the present invention, the cigarette filter has a hardness of 80% or more 5 minutes after injecting 20 to 25 parts by weight of water, based on 100 parts by weight of lyocell tow. Specifically, the hardness of the cigarette filter after injecting water may be 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, or 86% or more. The hardness of the cigarette filter after injecting water is measured using the same method as before injecting water. Measuring the hardness of the cigarette filter after injecting water to confirm its durability against moisture takes into consideration the change in hardness of the cigarette filter until the smoker finishes smoking. The amount of water injected and the elapsed time are determined taking into consideration the actual smoking experience of a smoker. The average amount of moisture contained in a cigarette filter after a smoker actually smokes is at the level of 8 parts by weight, and injecting 20 to 25 parts by weight of water represents a more severe condition than the actual smoking situation. The cigarette filter according to one embodiment of the present invention can maintain an excellent hardness of 85% or more while the smoker is holding the cigarette during smoking.

[0035] The moisture disintegration degree, which means the change in hardness due to the injection of water, can be calculated by comparing the hardness before and after the injection of water. According to one embodiment of the present invention, the cigarette filter has a moisture disintegration degree of 7% or less. Specifically, the moisture disintegration degree of the cigarette filter may be 7% or less, 6.5% or less, 6% or less, 5.5% or less, or 5% or less. The moisture disintegration degree can be calculated based on the hardness before and after the injection of water using the following calculation formula 2:

[0036] [Formula 2] Moisture disintegration rate (%) = (1-D2 / D1) x 100

[0037] Here, D1 means the hardness (%) before water is poured in, and D2 means the hardness (%) after water is poured in. The low water disintegration is significant in that the hardness after water is poured in may be high, but from the smoker's point of view, it is also technically significant in that it minimizes the change in the tactile sensation felt from the cigarette filter when smoking.

[0038] According to one embodiment of the present invention, the binder includes polyester. The polyester has the function of binding lyocell fibers and imparting hardness to the lyocell tow. Specifically, the polyester is a synthetic resin made by reacting a polyhydric organic acid with a polyhydric alcohol, and has appropriate resistance to water and various compounds. According to one embodiment of the present invention, the polyester has a weight-average molecular weight of 1,000 to 50,000, specifically 1,500 to 30,000, more specifically 2,000 to 10,000. If the molecular weight is below this range, the resistance to water and the like may be reduced, and if the molecular weight is above this range, it is difficult to properly disperse the polyester in the lyocell tow.

[0039] According to one embodiment of the present invention, the polyester is a copolymer of an aromatic monomer and an aliphatic monomer. The aromatic monomer imparts structural stability to the polyester, while the aliphatic monomer imparts structural flexibility to the polyester. A polyester containing both an aromatic and an aliphatic monomer can easily bond with other components, such as lyocell fibers, providing binder functionality. The aromatic monomer may be a polyhydric organic acid or a polyhydric alcohol, and the aliphatic monomer may also be a polyhydric organic acid or a polyhydric alcohol. The polyester exhibits low viscosity in aqueous solution, making it easy to apply by spraying. According to one embodiment of the present invention, the polyester has a viscosity of less than 5 cps, 4 cps or less, 3 cps or less, or 2 cps or less at 40°C for a 15 wt% aqueous polyester solution. Here, a 15 wt% aqueous polyester solution refers to a solution of 15 wt% polyester and 85 wt% water.

[0040] According to one embodiment of the present invention, the aromatic monomer is a dicarboxylic acid having a C5 to C12 arylene group or a heteroarylene group. Exemplarily, the dicarboxylic acid having a C5 to C12 arylene group or a heteroarylene group may be phthalic acid, terephthalic acid, or isophthalic acid. According to one embodiment of the present invention, the aliphatic monomer is a diol having a C1 to C6 alkylene group, a dicarboxylic acid having a C2 to C12 alkylene group, or a combination thereof. Exemplarily, the diol having a C1 to C6 alkylene group is ethylene glycol, and the dicarboxylic acid having a C2 to C12 alkylene group is sebacic acid. In the case of polyesters, because carboxylic acid groups and hydroxyl groups can be formed by a condensation reaction in a ratio of 1:1, the carboxylic acid group-containing monomer can be the above-mentioned dicarboxylic acid having a C5 to C12 arylene or heteroarylene group, dicarboxylic acid having a C2 to C12 alkylene group, or a combination thereof, and the hydroxyl group-containing monomer can be a diol having a C1 to C6 alkylene group. The arylene group, heteroarylene group, or alkylene group can be substituted or unsubstituted. When substituted, the main chain of the arylene group, heteroarylene group, or alkylene group can be substituted with a substituent commonly known in the art, such as a C1 to C4 alkyl group, a C1 to C4 alkoxy group, or a halogen group.

[0041] The polyester can be contained in a solvent such as water and applied to the lyocell tow in the form of a binder solution, which is then dried to remove some or all of the solvent. Even after drying, the polyester remains interspersed between the lyocell fibers, improving the hardness of the lyocell tow. According to one embodiment of the present invention, the polyester is contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the lyocell tow. Specifically, the content of the polyester is 0.1 to 5 parts by weight, 0.2 to 0.3 parts by weight, or 0.4 to 5 parts by weight, 4 to 3.5 parts by weight, 3 to 2.5 parts by weight, or 0.1 to 5 parts by weight, 0.2 to 4 parts by weight, or 0.3 to 3 parts by weight. When the polyester is applied within the above range, it can increase the hardness of the lyocell tow to an appropriate level without reducing its basic filtering function.

[0042] The binder may contain other binder components in addition to the polyester. Examples of such binder components include hydroxyl propyl methyl cellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA), polyvinyl acetate (PVAc), and polyvinyl pyrrolidone (PVP). According to one embodiment of the present invention, the binder may further contain hydroxypropyl methyl cellulose or polyvinyl pyrrolidone, specifically hydroxypropyl methyl cellulose, in addition to the polyester. The binder may exhibit a synergistic effect when used with the polyester in terms of its binder function. According to one embodiment of the present invention, the weight ratio of polyester to hydroxypropyl methyl cellulose or polyvinyl pyrrolidone in the binder is 1:1 to 1:3. Specifically, the weight ratio of polyester to hydroxypropyl methylcellulose or polyvinylpyrrolidone may be 1:1 to 1:3, 1:1.5 to 1:3, 1:2 to 1:3, or 1:2 to 1:2.5. When the polyester is used together with other binder components, adjusting the content ratio within the above range can provide a synergistic effect through the combination.

[0043] The above-mentioned cigarette filter can be manufactured by the following manufacturing method. The manufacturing method includes the steps of: manufacturing lyocell tow using lyocell fiber; mixing a binder and a solvent to prepare a binder solution; spraying the binder solution onto the lyocell tow and drying it; and wrapping the dried lyocell tow in cigarette paper to manufacture a cigarette filter. Since the manufacturing method basically relates to a method for manufacturing the above-mentioned cigarette filter, a description of the specific parts embodied in the above content will be omitted, and the following will describe the characteristics of the manufacturing method in more detail.

[0044] First, lyocell tow is produced using a plurality of lyocell fibers. The produced lyocell tow has a bundle shape formed by cross-linking adjacent lyocell fibers. In this process, a step of expanding the tow through blooming is further carried out. Expanding the tow through the blooming step allows the binder solution sprayed thereafter to easily penetrate between the lyocell fibers that make up the lyocell tow.

[0045] Next, a binder solution is prepared by mixing a binder and a solvent. The binder solution is a substance sprayed onto the lyocell tow to improve its functionality, such as its hardness. Since some components of the binder solution may be lost during the drying process after spraying, the composition of the binder solution may differ from the composition of the components constituting the cigarette filter. The binder may be embodied as described above, and since the components do not particularly disappear even after drying, the amount supplied to the lyocell tow through spraying remains almost unchanged in the final cigarette filter. The solvent contains water, and some of the water is lost during the drying process. When the binder solution is prepared using only a binder and water, the water content is the portion of the binder solution excluding the binder content. According to one embodiment of the present invention, the binder is included in an amount of 5 to 40 parts by weight based on 100 parts by weight of the binder solution. Specifically, the content of the binder is 5 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, and 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, or may be 5 to 40 parts by weight, 7 to 30 parts by weight, or 10 to 20 parts by weight. When a binder solution is formed within the above range, the binder can be easily sprayed and applied to the lyocell tow.

[0046] The binder solution prepared as described above is sprayed onto the lyocell tow. The binder solution can be sprayed onto the lyocell tow to an extent that overcomes the inherent hardness and other problems inherent to the lyocell tow without impairing the lyocell tow's basic filtering function. According to one embodiment of the present invention, 5 to 30 parts by weight of the binder solution is sprayed onto the lyocell tow, based on 100 parts by weight of the lyocell tow. Specifically, the amount of the binder solution sprayed is 5 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, or 10 parts by weight or more, and is 30 parts by weight or less, 28 parts by weight or less, 26 parts by weight or less, 24 parts by weight or less, 22 parts by weight or less, or 20 parts by weight or less, and may be 5 to 30 parts by weight, 7 to 24 parts by weight, or 10 to 20 parts by weight. When the binder solution is sprayed within the above range, it can improve the functionality of the lyocell tow, such as its hardness. The method of spraying the binder solution may be a method commonly used in the art and is not particularly limited. For example, the binder solution may be sprayed using a nozzle spray, a brush spray, or an electric spray.

[0047] After the binder solution is sprayed onto the lyocell tow, it is dried to reduce the amount of water and ensure hardness. The method for drying the lyocell tow may be a method commonly used in the art and is not particularly limited. For example, the drying may be performed so that the amount of water initially sprayed is reduced by 30% or more.

[0048] The dried lyocell tow is wrapped in cigarette paper to produce a cigarette filter. If necessary, the lyocell tow can be processed to a suitable standard for application to a cigarette filter using a mechanical roll or cutter.

[0049] The above-described cigarette filter can be applied to a smoking article. Fig. 1 shows a schematic configuration of a smoking article according to one embodiment of the present invention. The smoking article 100 includes a smoking material portion 10 and a filter portion 20, and the above-described cigarette filter is applied to the filter portion 20 of the smoking article 100. In the smoking article 100, the smoking material portion 10 is located upstream of the filter portion 20.

[0050] The smoking material portion 10 can be filled with smoking material such as raw tobacco, flakes, or a mixture of leaf tobacco and flakes. Processed smoking material can be filled into the smoking material portion 10 in sheet or shredded form. The smoking material portion 10 can have an elongated rod shape, and its length, circumference, and diameter can be adjusted to sizes commonly used in the art, taking into account, but not limited to, the amount of smoking material to be filled and the user's preferences. The smoking material portion 10 can contain at least one aerosol-generating substance selected from the group consisting of glycerin, propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and oleyl alcohol. The smoking material portion 10 can also contain other additives, such as flavorants, humectants, and / or acetate compounds. The aerosol-generating substance and additives can be incorporated into the smoking material.

[0051] The filter unit 20 is disposed downstream of the smoking material unit 10 and serves as a filter through which aerosol generated in the smoking material unit 10 passes just before the user inhales. The filter unit 20 can be manufactured using various materials and shapes. The filter unit 20 according to one embodiment of the present invention basically includes the above-mentioned cigarette filter containing lyocell tow, in which a plurality of lyocell fibers are bound together by a binder. The cigarette filter containing lyocell tow can replace all or part of the filter unit 20 of a conventional smoking article, and when replacing only part of it, conventional filter materials can be used together. Conventional filter materials include, for example, cellulose acetate filters and hollow tube filters.

[0052] 1 shows that the filter unit 20 is a mono-filter consisting of a single filter, but is not limited to this. For example, the filter unit 20 may be a dual filter or triple filter equipped with two acetate filters to increase filtering efficiency. Furthermore, although not shown, the filter unit 20 may contain a crushable capsule (not shown) having a structure in which a flavor-containing oral liquid is encapsulated in a coating.

[0053] The exterior of the smoking material portion 10 and the filter portion 20 may be wrapped in a wrapper 30a or 30b.

[0054] The smoking material portion 10 can be wrapped in a smoking material wrapper 30a. A portion of the tobacco smoke generated during the combustion of a typical smoking material portion 10 is released into the atmosphere through the smoking material wrapper 30a before passing through the cigarette filter, resulting in sidestream smoke that is unpleasant for secondhand smokers. Various attempts have been made to reduce sidestream smoke, such as incorporating fillers such as magnesium oxide, titanium oxide, cerium oxide, aluminum oxide, calcium carbonate, and zirconium carbonate into cigarette paper. However, simply applying these fillers to reduce sidestream smoke can result in a decrease in smoking experience, burn-off, and ash caking, making it difficult to solve these problems through an appropriate combination of fillers. The smoking material wrapper 30a according to one embodiment of the present invention uses a filler containing a mixture of magnesium oxide (MgO and / or Mg(OH)2) and calcium carbonate (CaCO3) to reduce sidestream smoke while preventing the decrease in smoking experience, burn-off, and ash caking.

[0055] The filter part 20 may be wrapped in a filter part wrapper 30b. The filter part wrapper 30b may be made of oil-resistant wrapping paper, and may further include aluminum foil on the inner surface of the filter part wrapper 30b.

[0056] The smoking material section 10 wrapped in the smoking material section wrapper 30a and the filter section 20 wrapped in the filter section wrapper 30b can be bound and wrapped with tipping paper 40. As shown in FIG. 1, the tipping paper 40 may be wrapped around at least a portion (e.g., a downstream region) of the smoking material section wrapper 30a and the outer shell of the filter section wrapper 30b. In other words, at least a portion of the smoking material section 10 and the filter section 20 may be further wrapped and physically bound with the tipping paper 40. According to one embodiment of the present invention, the tipping paper 40 may be made of, but is not limited to, non-porous wrapping paper that has not been treated for oil resistance. The tipping paper 40 may also contain, but is not limited to, a non-flammable material to prevent the filter section 20 from burning.

[0057] The configuration and effects of the present invention will be described in more detail below with reference to examples and comparative examples. However, these examples are intended to more specifically explain the present invention, and the scope of the present invention is not limited to these examples.

[0058] Example Example 1 Lyocell tow with a tow fiber bundle of approximately 35,000 denier was used, using Lyocell fibers with a fiber diameter of approximately 3.0 denier. A binder solution, which is a mixture of a binder and a solvent, was also prepared. Specifically, the binder solution contained 15% by weight of polyester (a copolymer of phthalic acid, sebacic acid, and ethylene glycol), a weight-average molecular weight (M w ) = 3,000 to 6,000) was added to 85 wt% water to prepare the binder solution. The prepared binder solution was sprayed onto lyocell tow through a nozzle spray. The binder solution was sprayed at 15 wt% based on the weight of the lyocell tow and dried. The dried lyocell tow was wrapped in cigarette paper to prepare a cigarette filter with an axial length of approximately 108 mm and a circumference of approximately 24.20 mm.

[0059] Example 2 Cigarette filters were prepared in the same manner as in Example 1, except that 3 wt. % polyester and 7 wt. % hydroxypropylmethylcellulose (Pharmacoat 606) were used in place of 15 wt. % polyester in the binder solution.

[0060] Example 3 Cigarette filters were prepared in the same manner as in Example 1, except that 3 wt % polyester and 7 wt % polyvinylpyrrolidone (K25) were used in place of 15 wt % polyester in the binder solution.

[0061] Comparative Example 1 The cigarette filters were produced without spraying the lyocell tow with a binder solution.

[0062] Experimental Example Experimental Example 1: Evaluation of the hardness of cigarette filters The hardness of the cigarette filters manufactured in Examples 1 to 3 and Comparative Example 1 was measured. In addition, to measure the degree to which the cigarette filters are broken down by moisture, about 20 μl (22% by weight based on lyocell tow) of water was injected into each of the cigarette filters using a syringe, and the hardness of the cigarette filters was measured after about 5 minutes. Specifically, the hardness of the cigarette filters was measured using a filter hardness tester (DHT 200 from Filtrona). TM ) and was measured using the following calculation formula 1.

[0063] [Formula 1] Filter hardness (%) = [Da] / D x 100

[0064] Here, D is the filter diameter, and a is the distance (mm) that a 300 g weight moves down (presses the filter).

[0065] [Table 1] * Moisture disintegration rate (%) = (1-D2 / D1) x 100 (Here, D1 means hardness (%) before water is added, and D2 means hardness (%) after water is added.)

[0066] According to Table 1, when the binder solution contained polyester (Examples 1 to 3), the hardness before the water injection was 85% or more, specifically 90% or more, and the hardness after the water injection was 80% or more, specifically 85% or more, showing excellent hardness. According to Examples 2 and 3, the polyester was able to maintain excellent hardness even when used in combination with other types of binders such as hydroxypropyl methylcellulose and polyvinylpyrrolidone.

[0067] The results show that the hardness after water injection is a value related to the minimum hardness until the smoker finishes smoking, and when polyester is used as a binder (Examples 1 to 3), the hardness is maintained at 80% or more until the smoker finishes smoking, so the cigarette filter structure does not feel like it is collapsing when smoking. Nevertheless, when polyester alone or a combination of polyester and hydroxypropyl methylcellulose is used as a binder (Examples 1 and 2), the degree of water disintegration is low, at 7% or less, specifically 6% or less, so the change in the feel of the cigarette filter that the smoker feels when smoking is even less.

[0068] In contrast, when a binder solution such as polyester is not used (Comparative Example 1), cigarette filters containing lyocell tow are very vulnerable to moisture and their structure may change not only during smoking but also during storage under harsh conditions with a certain amount of moisture, which is undesirable.

[0069] Experimental Example 2: Evaluation of viscosity and adhesive strength of binder solution The viscosity and adhesive strength of the binder solutions used in Examples 1 and 2 were measured and are shown in Table 2 below. The viscosity was measured using a Brookfield Spindle No. 61 device at a temperature of 40°C. The adhesive strength was measured by applying the binder solution of Example 1 (15% by weight polyester and 85% by weight water) and the binder solution of Example 2 (3% by weight polyester, 7% by weight hydroxypropylmethylcellulose and 90% by weight water) to a nonwoven fabric, laminating it with art paper having a basis weight of 100 gsm, drying it, and then using a tensile tester (Tinius Olsen, Universal Testing Machine 10ST series).

[0070] [Table 2]

[0071] According to Table 2, the polyester contained in the binder solution exhibited such high adhesive strength that it destroyed the adherend when it dried, despite being a substance with very low viscosity. The binder solution containing polyester has low viscosity, so it can be easily dispersed and uniformly distributed in the target material such as lyocell tow, and it exhibits excellent adhesive strength after drying, making it suitable for imparting functionality such as hardness to lyocell tow.

[0072] Although the embodiments have been described above by way of limited examples and drawings, those skilled in the art will appreciate that various modifications and variations may be made from the above description, for example, the techniques described may be performed in a different order than described, and / or the components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different manner than described, or may be substituted or replaced by other components or equivalents, and still achieve suitable results.

[0073] [Item 1] a lyocell tow made of a plurality of lyocell fibers; a binder that binds the lyocell fibers together; A cigarette filter with a hardness of 85% or more. [Item 2] Item 2. The cigarette filter according to item 1, wherein the cigarette filter has a hardness of 80% or more even 5 minutes after 20 to 25 parts by weight of water, based on 100 parts by weight of lyocell tow, is poured therein. [Item 3] 3. The cigarette filter according to item 2, wherein the cigarette filter has a water disintegration rate of 7% or less. [Item 4] 4. The cigarette filter according to any one of items 1 to 3, wherein the binder comprises a polyester. [Item 5] 5. The cigarette filter according to item 4, wherein the polyester is a copolymer of an aromatic monomer and an aliphatic monomer. [Item 6] 5. The cigarette filter according to item 4, wherein the polyester has a viscosity of less than 5 cps at 40°C in a 15% by weight aqueous polyester solution. [Item 7] 6. The cigarette filter according to item 5, wherein the aromatic monomer is a dicarboxylic acid having a C5 to C12 arylene group or heteroarylene group. [Item 8] 6. The cigarette filter according to item 5, wherein the aliphatic monomer is a diol having a C1 to C4 alkylene group, a dicarboxylic acid having a C2 to C12 alkylene group, or a combination thereof. [Item 9] 5. The cigarette filter according to item 4, wherein the polyester is contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the lyocell tow. [Item 10] Item 5. The cigarette filter according to item 4, wherein the binder further comprises hydroxypropyl methylcellulose or polyvinylpyrrolidone. [Item 11] Item 11. The cigarette filter according to item 10, wherein the weight ratio of polyester to hydroxypropyl methylcellulose or polyvinylpyrrolidone in the binder is 1:1 to 1:3. [Explanation of symbols]

[0074] 10. Smoking Substances Section 20 Filter section 30a Smoking Substances Section Wrapper 30b filter wrapper 40 Tip Paper 100 Smoking articles

Claims

1. Lyocell toe, which consists of multiple lyocell fibers, The lyocell fibers are bound together by a binder, A cigarette filter having a hardness of 85% or more, The binder includes polyester, The hardness is calculated using the following formula 1: [Formula 1] Filter hardness (%) = [D - a] / D × 100 D is the filter diameter (mm), and a is the distance (mm) at which the cigarette filter is pressed by a 300g weight. Cigarette filter.

2. The tobacco filter according to claim 1, wherein the tobacco filter has 80% or more of the hardness even 5 minutes after injecting 20 to 25 parts by weight of water based on 100 parts by weight of lyocell.

3. The aforementioned tobacco filter has a moisture disintegration degree of 7% or less. The degree of water decay mentioned above is calculated using the following formula 2: [Formula 2] Degree of water decay (%) = (1 - D) ２ / D １ ) × 100 D １ This refers to the hardness (%) before water is added, and D ２ The tobacco filter according to claim 2, wherein indicates the hardness (%) after water injection.

4. The tobacco filter according to any one of claims 1 to 3, wherein the polyester has a weight-average molecular weight of 1,000 to 50,000.

5. The tobacco filter according to any one of claims 1 to 3, wherein the polyester has a viscosity of less than 5 cps at 40°C in a 15% by weight aqueous solution of polyester.

6. The tobacco filter according to any one of claims 1 to 3, wherein the polyester comprises 0.1 to 5 parts by weight based on 100 parts by weight of lyocell.

7. The tobacco filter according to any one of claims 1 to 3, wherein the binder further comprises hydroxypropyl methylcellulose or polyvinylpyrrolidone.

8. The tobacco filter according to claim 7, wherein the weight ratio of polyester to hydroxypropyl methylcellulose or polyvinylpyrrolidone in the binder is 1:1 to 1:3.

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