Tobacco filters containing lyocelt

Abstract

Provided is a cigarette filter comprising a lyocell tow made of a plurality of lyocell fibers and a binder for binding the lyocell fibers together, the cigarette filter having a hardness of 85% or more. The cigarette filter according to one embodiment of the present invention has a hardness of 80% or more even 5 minutes after 20 to 25 parts by weight of water is poured based on 100 parts by weight of the lyocell tow. The cigarette filter according to one embodiment of the present invention has a water disintegration rate of 7% or less. The cigarette filter according to one embodiment of the present invention overcomes the material problems that the conventional lyocell tow has, and has high hardness and low water disintegration rate.

Description

Technical Field

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

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

Background Art

[0003] Generally, in order to manufacture tobacco, first, various types of leaf tobacco are blended and processed so as to obtain a desired aroma and taste. Next, the processed leaf tobacco is cut to produce cut tobacco leaf, and the cut tobacco leaf is wrapped with cigarette paper to produce a cigarette without a filter. Next, a filter is attached to the cigarette without a filter as needed.

[0004] Cigarette paper can be manufactured from flax, wood pulp, etc., and is required to maintain flammability and the taste of tobacco during combustion. A tobacco filter may contain activated carbon, flavor substances, etc., can be composed of a monofilter or a multi-filter, and is wrapped with cigarette filter wrapping paper. The cut tobacco part and the tobacco filter are connected by tipping paper, and the tipping paper may contain fine pores.

[0005] Conventional cigarette filters use cellulose acetate tow, which is made by extracting and acetylating cellulose from wood pulp. Recently, however, in order to protect the natural environment and reduce costs, alternative materials made from environmentally friendly materials are being developed. For example, tow is being developed using lyocell fibers, which are made by fibrousizing cellulose itself, unlike cellulose acetate. Hardness is an important indicator related to consumer needs and the workability of tobacco manufacturing in cigarette filters. When cigarette filters are manufactured using tows, which are bundles of fiber strands, the resulting filters are unsuitable due to their low hardness. To be usable as cigarette filters, the hardness needs to be increased to a certain level or higher. For example, there are two methods for increasing the hardness of filters: using hardening agents and using plasticizers. The method using hardening agents involves using a binder-like substance to bond the fiber strands together and impart hardness to the filter, making it stronger. The method using plasticizers involves using a specific substance to partially dissolve or plasticize the fibers themselves to form joints between the fibers, and then plasticizing them.

[0006] Conventional cellulose acetates utilize plasticizers (triacetin, triethyl citrate) to partially dissolve the fiber strands, and the principle of hardening the fiber strands together is used to impart hardness to cigarette filters. However, since there are currently no plasticizers available for lyocell fibers, it is essential to develop a hardness enhancer suitable for lyocell fibers.

[0007] Unlike hydrophobic cellulose acetate, the aforementioned lyocell fibers are known to be hydrophilic. Therefore, even if their hardness is increased with a hardness enhancer and they are applied to cigarette filters, it is important to consider that their structure will not collapse due to moisture supplied by smokers during smoking.

[0008] The inventors recognized the technical challenges with the lyocell fiber material described above and, after continuous research into functional lyocell tow suitable for application in cigarette filters, completed the present invention. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Korean Patent Publication No. 10-2015-0035800 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] This invention aims to provide a tobacco filter that addresses the inherent material problems of lyocell, such as its hardness and moisture degradation properties, in a tobacco filter that incorporates lyocell 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 tobacco 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 specific example of the present invention, the tobacco filter retains a hardness of 80% or more even 5 minutes after injecting 20 to 25 parts by weight of water based on 100 parts by weight of lyocell.

[0013] In one specific example of the present invention, the tobacco filter has a moisture disintegration degree of 7% or less.

[0014] In one specific example of the present invention, the binder includes polyester.

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

[0016] In one specific example of the present invention, the polyester has a viscosity of less than 5 cps at 40 °C with respect to an aqueous polyester solution having a concentration of 15% by weight.

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

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

[0019] In one specific example of the present invention, the polyester contains 0.1 to 5 parts by weight based on 100 parts by weight of lyocell tow.

[0020] In one specific example of the present invention, the binder further contains hydroxypropyl methylcellulose or polyvinylpyrrolidone.

[0021] In one specific example of the present invention, the weight ratio of polyester to hydroxypropyl methylcellulose or polyvinylpyrrolidone in the binder is 1:1 to 1:3.

Advantages of the Invention

[0022] The cigarette filter according to one specific example of the present invention contains lyocell tow, which is an environmentally friendly material, and overcomes the material problems that lyocell tow has conventionally had, and has excellent hardness of 90% or more.

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

Brief Description of the Drawings

[0024] [Figure 1] It is a diagram showing a schematic configuration of a smoking article according to a specific example of the present invention.

Embodiments for Carrying out the Invention

[0025] Hereinafter, specific examples will be described in detail based on exemplary drawings. When adding reference numerals to the components of each drawing, it should be noted that for the same components, as far as possible, the same numerals are used even if they are shown in different drawings. Also, when explaining a specific example, if it is determined that a specific explanation of a related known configuration or function hinders the understanding of the specific example, the detailed explanation thereof will be omitted.

[0026] In addition, when explaining the components of a specific example, terms such as first, second, A, B, (a), (b), etc. can be used. These terms are for distinguishing the components from other components, and the essence, order, or sequence of the components are not limited by these terms. When it is described that any component is "connected", "coupled", or "joined" to another component, it should be understood that the component may be directly connected or joined to the other component, but other components may also be "connected", "coupled", or "joined" between the components.

[0027] Components included in any one specific example and components having a common function will be described using the same names in other specific examples. Unless otherwise stated, the description given in any one specific example can also be applied to other embodiments, and specific descriptions within the overlapping range will be omitted.

[0028] In this specification, the term "smoking article" may mean any object capable of generating an aerosol, such as a cigarette or cigar. A smoking article may contain an aerosol-generating substance or an aerosol-forming substrate. A smoking article may also contain a solid substance based on tobacco raw materials, such as flat tobacco leaves, shredded tobacco, or reconstituted tobacco. The smoking substance may contain volatile compounds. The smoking article may contain several segments, each having a different function, and such segments are indicated by "...parts". In this specification, a smoking article may include not only combustion-type cigarettes but also heated cigarettes used with an aerosol-generating device (not shown), such as an e-cigarette device.

[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 the user draws air using the smoking article. The smoking article includes an upstream end (i.e., the part where air enters) and a downstream end (i.e., the part where air exits) opposite it. When using the smoking article, the user may 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 written as “terminal.”

[0030] The present invention relates to a tobacco filter applicable to smoking articles. According to one specific example of the present invention, the tobacco filter includes a lyocell tow made of a plurality of lyocell fibers and a binder that binds the lyocell fibers together. The lyocell fibers are environmentally friendly fibers made from cellulose extracted from wood pulp. The lyocell tow refers to a bundle formed by the cross-binding of adjacent lyocell fibers. According to one specific example of the present invention, the lyocell fibers may have a fineness of 1.0 denier to 12.0 denier. According to one specific example of the present invention, the lyocell fiber bundle constituting the lyocell tow may have a fineness of 15,000 denier to 45,000 denier. By mixing a binder suitable for the lyocell fibers with a solvent to produce a binder solution, spraying this solution onto the lyocell tow, and then drying it, the lyocell tow can form a structure with a hardness of a certain level or higher.

[0031] A tobacco filter containing lyocell tofu according to one specific example of the present invention has excellent hardness due to the binding of the binder and also has excellent resistance to moisture. According to one specific example of the present invention, the tobacco filter has a hardness of 85% or more. Specifically, the hardness of the tobacco 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 tobacco filter is a numerical value that quantifies the degree to which the diameter of the tobacco filter is maintained when the tobacco filter is pressed with a constant level of force in the vertical direction, and can be specifically calculated by the following calculation formula 1.

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

[0033] Here, D is the filter diameter (mm), and a is the distance (mm) that a 300g weight descends (the filter is pressed). The measurements necessary for calculating the hardness of the tobacco filter can be obtained using equipment commonly used in the art, for example, Filtrona's DHT 200TM This can be used. When measuring hardness, the force applied takes into account the force actually applied by a smoker when gripping a cigarette. The hardness value of 85% or more obtained through a cigarette filter according to one specific example of the present invention has technical significance in that it is possible to ensure a level of hardness that can replace conventional cigarette filters made of cellulose acetate by using lyocell, an environmentally friendly material.

[0034] The hardness of the tobacco filter described above indicates the hardness when a smoker first grasps the cigarette to smoke it, and such hardness does not guarantee that the hardness of the tobacco filter will be maintained until the smoker finishes smoking. When a smoker smokes, a considerable amount of moisture can flow into the tobacco filter, and in this case, if the filter containing lyocell tow has durability to a certain level or higher of moisture, it is easy to maintain the initial hardness. Unlike hydrophobic-based cellulose acetate, the lyocell fibers are known to be hydrophilic substances, and therefore, due to the properties of the material, it is not easy to maintain hardness. According to one specific example of the present invention, the tobacco filter has a hardness of 80% or more even 5 minutes after injecting 20 to 25 parts by weight of water based on 100 parts by weight of lyocell tow. Specifically, after injecting water, the hardness of the tobacco filter may be 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, or 86% or more. After injecting water, the hardness of the tobacco filter is also measured in the same way as before injecting water. Measuring the hardness of the tobacco filter after injecting water to confirm its resistance to moisture takes into account the change in the hardness of the tobacco filter until the smoker finishes smoking. The amount of water injected and the elapsed time are based on the actual smoking conditions of a smoker. In reality, the amount of moisture contained in a tobacco filter after a smoker has finished smoking is at an average level of 8 parts by weight, and injecting 20 to 25 parts by weight of water represents conditions more severe than actual smoking. A tobacco filter according to one specific example of the present invention can maintain an excellent hardness of 85% or more while the smoker is holding the tobacco during smoking.

[0035] By comparing the hardness before and after water injection, the degree of water disintegration, which represents the change in hardness due to water injection, can be calculated. According to one specific example of the present invention, the tobacco filter has a degree of water disintegration of 7% or less. Specifically, the degree of water disintegration of the tobacco filter may be 7% or less, 6.5% or less, 6% or less, 5.5% or less, or 5% or less. The degree of water disintegration is basically based on the hardness before and after water injection and can be calculated using the following formula 2.

[0036] [Formula 2] Water decay rate (%) = (1 - D2 / D1) × 100

[0037] Here, D1 represents the hardness (%) before water injection, and D2 represents the hardness (%) after water injection. The aforementioned low degree of water disintegration is significant because it allows for a higher hardness after water injection, but from the smoker's perspective, it has technical significance because it reduces the change in tactile sensation felt from the cigarette filter during smoking.

[0038] According to one specific example of the present invention, the binder includes polyester. The polyester has the functionality 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 specific example of the present invention, the polyester has a weight-average molecular weight of 1,000 to 50,000, specifically 1,500 to 30,000, and more specifically 2,000 to 10,000. If the molecular weight is below the above range, the resistance to water and the like may decrease, and if the molecular weight is above the above range, it is not easy to properly disperse it in the lyocell tow.

[0039] According to one specific example of the present invention, the polyester is a copolymer of an aromatic monomer and an aliphatic monomer. The aromatic monomer adds structural stability to the polyester, and the aliphatic monomer adds structural flexibility to the polyester, so that the polyester containing the aromatic monomer and the aliphatic monomer can easily adhere to other components such as lyocell fibers and add functionality as a binder. The aromatic monomer may be a polyhydric organic acid or a polyhydric alcohol, and similarly, the aliphatic monomer may also be a polyhydric organic acid or a polyhydric alcohol. The polyester exhibits low viscosity in aqueous solution and is easy to apply by spraying in aqueous solution. According to one specific example of the present invention, the polyester has a viscosity of less than 5 cps, 4 cps or less, 3 cps or less, and 2 cps or less at 40°C in a 15 wt% concentration aqueous solution of polyester. Here, a 15 wt% concentration aqueous solution of polyester means a solution obtained by mixing 15 wt% polyester and 85 wt% water.

[0040] According to one specific example of the present invention, the aromatic monomer is a dicarboxylic acid having a C5-C12 allylene group or heteroalylene group. For example, the dicarboxylic acid having a C5-C12 allylene group or heteroalylene group may be phthalic acid, terephthalic acid, or isophthalic acid. According to one specific example of the present invention, the aliphatic monomer is a diol having a C1-C6 alkylene group, a dicarboxylic acid having a C2-C12 alkylene group, or a combination thereof. For example, the diol having a C1-C6 alkylene group is ethylene glycol, and the dicarboxylic acid having a C2-C12 alkylene group is sebacic acid. In the case of polyesters, since carboxylic acid groups and hydroxyl groups can be formed by condensation reactions in a 1:1 ratio, the monomers having carboxylic acid groups include dicarboxylic acids having C5-C12 allylene groups or heteroalylene groups, dicarboxylic acids having C2-C12 alkylene groups, or combinations thereof. The monomer having a hydroxyl group includes diols having C1-C6 alkylene groups. The allylene groups, heteroalylene groups, or alkylene groups exist in a substituted or unsubstituted state. In the substituted state, substituents commonly known in the art, such as C1-C4 alkyl groups, C1-C4 alkoxy groups, or halogen groups, may be substituted on the main chain of the allylene group, heteroalylene group, or alkylene group.

[0041] The polyester is contained in a solvent such as water and can be applied to the lyocell tow in the form of a binder solution, after which it is dried to remove some or all of the solvent. Even after drying, the polyester remains positioned between each lyocell fiber, improving the hardness of the lyocell tow. According to one specific example of the present invention, the polyester is contained in amounts of 0.1 to 5 parts by weight based on 100 parts by weight of lyocell tow. Specifically, the polyester content may be 0.1 parts by weight or more, 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, 5 parts by weight or less, 4.5 parts by weight or less, 4 parts by weight or less, 3.5 parts by weight or less, 3 parts by weight or less, 2.5 parts by weight or less, and may be 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, the hardness of the lyocell tow can be increased to an appropriate level without reducing its basic filtering function.

[0042] The binder may contain other binder components along with the polyester. Examples of these other binder components include hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA), polyvinyl acetate (PVAc), or polyvinylpyrrolidone (PVP). According to one specific example of the present invention, the binder may further contain hydroxypropyl methylcellulose or polyvinylpyrrolidone, specifically hydroxypropyl methylcellulose, along with the polyester. The binder can exhibit a synergistic effect when used with the polyester in terms of its binder functionality. According to one specific example of the present invention, the weight ratio of polyester to hydroxypropyl methylcellulose or polyvinylpyrrolidone 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 using the polyester together with other binder components, adjusting the content ratio within the above range can yield synergistic effects through the combination.

[0043] The tobacco filter described above can be manufactured by the following manufacturing method. The manufacturing method includes the steps of: manufacturing lyocell tow using lyocell fibers; manufacturing a binder solution by mixing a binder and a solvent; spraying the binder solution onto the lyocell tow and drying it; and manufacturing a tobacco filter by wrapping the dried lyocell tow in rolling paper. Since the manufacturing method is basically the same as the method for manufacturing the tobacco filter described above, the explanation of the specific parts described above will be omitted, and the characteristics of the manufacturing method will be explained in more detail below.

[0044] First, a lyocell tow is manufactured using multiple lyocell fibers. The manufactured lyocell tow has a bundle shape formed by the cross-linking of adjacent lyocell fibers. At this stage, a further step is performed to inflate the tow through blooming. When the tow is inflated through the blooming step, the binder solution that is subsequently sprayed can easily penetrate between the lyocell fibers that make up the lyocell tow.

[0045] Next, a binder solution is prepared by mixing the binder and the solvent. The binder solution is a substance sprayed onto the lyocell to improve its functionality, such as its hardness. Since some components of the binder solution may disappear during the drying process after spraying, the composition of the binder solution may differ from the composition of the components that make up the tobacco filter. The binder can be materialized as described above, and since the components do not particularly disappear after drying, the amount supplied to the lyocell through spraying remains almost unchanged in the final tobacco filter. The solvent contains water, and some of the water disappears during the drying process. When a binder solution is prepared using only the binder and water, the portion of the binder solution remaining after deducting the binder content is the water content. According to one specific example of the present invention, the binder is contained in an amount of 5 to 40 parts by weight based on 100 parts by weight of the binder solution. Specifically, the binder content may be 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, 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 5 to 40 parts by weight, 7 to 30 parts by weight, or 10 to 20 parts by weight. The binder is easy to apply to the lyocelto by spraying when forming a binder solution within the above ranges.

[0046] The binder solution produced according to the above description is sprayed onto the lyocell tou. The binder solution can be sprayed onto the lyocell tou to an extent that it can resolve problems such as hardness inherent in the material of the lyocell tou without reducing the lyocell tou's basic function as a filter. According to one specific example of the present invention, the binder solution is sprayed onto the lyocell tou at a rate of 5 to 30 parts by weight, based on 100 parts by weight of the lyocell tou. 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, 10 parts by weight or more, 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, 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 range described above, it can improve the functionality of the lyocell tow, such as its hardness. The method of spraying the binder solution can be any method commonly used in the art and is not particularly limited. For example, the spraying of the binder solution can utilize nozzle spraying, brush spraying, or electrolysis.

[0047] After spraying the binder solution onto the lyocell tou, it is dried to reduce the amount of moisture and ensure hardness. The method for drying the lyocell tou can be any method commonly used in the art and is not particularly limited. The drying can be carried out, for example, to reduce the amount of moisture initially sprayed by 30% or more.

[0048] Dried lyocell tofu is wrapped in rolling paper to manufacture cigarette filters. If necessary, the lyocell tofu can be processed to a suitable standard for use in cigarette filters using a mechanical roll or cutting machine.

[0049] The tobacco filter described above can be applied to a smoking article. Figure 1 provides a schematic diagram showing the configuration of a smoking article according to one specific example of the present invention. The smoking article 100 includes a smoking substance section 10 and a filter section 20, and the tobacco filter described above is applied to the filter section 20 of the smoking article 100. In the smoking article 100, the smoking substance section 10 is located upstream of the filter section 20.

[0050] The smoking material section 10 can be filled with a smoking material such as raw tobacco leaves, plate-shaped leaves, or a mixture of tobacco leaves and plate-shaped leaves. The processed smoking material can be filled into the smoking material section 10 in sheet form or in shredded form. The smoking material section 10 may have an elongated rod form, and its length, circumference, and diameter are not particularly limited, but can be adjusted to a size commonly used in the art, taking into account the amount of smoking material to be filled, user preferences, etc. The smoking material section 10 may contain at least one aerosol-generating substance from among glycerin, propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, trietherene glycol, tetraethylene glycol, and oleyl alcohol. The smoking material section 10 may contain other additives such as flavoring agents, wetting agents, and / or acetate compounds. The aerosol-generating substances and additives may be contained in the smoking material.

[0051] The filter section 20 is positioned downstream of the smoking substance section 10 and acts as a filter through which the aerosol substance generated in the smoking substance section 10 passes immediately before the user inhales it. The filter section 20 can be manufactured from various materials or in various forms. A specific example of the filter section 20 according to the present invention basically includes the above-described tobacco filter containing lyocell tow, which is formed by bonding multiple lyocell fibers together with a binder. The tobacco filter containing lyocell tow can replace all or part of the filter section 20 of conventional smoking articles, and when replacing only a part, conventionally used filter materials can be used together. Conventional filter materials that can be used include, for example, cellulose acetate filters and hollow tube filters.

[0052] Figure 1 shows that the filter section 20 is a monofilter consisting of a single filter, but is not limited to this. For example, the filter section 20 may be provided as a dual filter or triple filter with two acetate filters to increase filtration efficiency. Although not shown, the filter section 20 may also contain a crushable capsule (not shown) with a structure in which the internal liquid containing fragrance is enclosed in a film.

[0053] The outside of the smoking substance section 10 and the filter section 20 can be wrapped with a wrapper 30a or 30b.

[0054] The smoking material section 10 can be wrapped with a smoking material section wrapper 30a. In the general smoking material section 10, some of the tobacco smoke generated during the combustion process is released into the atmosphere via the smoking material section wrapper 30a before passing through the tobacco filter, and this sidestream smoke causes discomfort to those who smoke indirectly. There have been various attempts to reduce such sidestream smoke, such as adding fillers such as magnesium oxide, titanium oxide, cerium oxide, aluminum oxide, calcium carbonate, and zirconium carbonate to conventional cigarette paper. However, simply applying such fillers to reduce sidestream smoke results in a decrease in flavor, combustion off, and a decrease in ash solidification, making it difficult to solve the above-mentioned problems through an appropriate combination of substances in the filler. In one specific example of the present invention, a smoking material section wrapper 30a is applied with a filler mixture of magnesium oxide (MgO and / or Mg(OH)2) and calcium carbonate (CaCO3) to reduce sidestream smoke while simultaneously preventing a decrease in flavor, ash solidification, and combustion off.

[0055] The filter section 20 can be packaged with a filter section wrapper 30b. The filter section wrapper 30b can be made of oil-resistant wrapping paper, and aluminum foil may be further included on the inner surface of the filter section wrapper 30b.

[0056] The smoking material portion 10, wrapped by the smoking material portion wrapper 30a, and the filter portion 20, wrapped by the filter portion wrapper 30b, can be joined together by chip paper 40. The chip paper 40 may wrap around at least a portion of the smoking material portion wrapper 30a (for example, a portion of the downstream area) and the outer casing of the filter portion wrapper 30b, as shown in Figure 1. In other words, at least a portion of the smoking material portion 10 and the filter portion 20 may be further wrapped and physically joined by chip paper 40. According to one specific example of the present invention, the chip paper 40 can be made from non-porous wrapping paper that has not been treated to be oil-resistant, but is not limited thereto. Furthermore, the chip paper 40 may also contain a non-flammable substance to prevent the filter portion 20 from burning, but is not limited thereto.

[0057] The configuration of the present invention and its effects will be described in more detail below based on examples and comparative examples. However, these examples are provided to illustrate the present invention more specifically, and the scope of the present invention is not limited to these examples.

[0058] Examples Example 1 Lyocell fibers with a density of approximately 3.0 denier per fiber were used to produce lyocell tow with a tow fiber bundle of approximately 35,000 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 and sebaciic acid and ethylene glycol, based on the total weight of the binder solution, with a weight-average molecular weight (M w The binder solution was prepared by adding (3,000-6,000) to 85% by weight of water. The prepared binder solution was sprayed onto the lyocell tofu through a nozzle sprayer. The binder solution was sprayed at 15% by weight of the lyocell tofu and dried. The dried lyocell tofu was wrapped in rolling paper to produce a cigarette filter with an axial length of approximately 108 mm and a circumference of approximately 24.20 mm.

[0059] Example 2 A tobacco filter was manufactured in the same manner as in Example 1, except that 3% by weight polyester and 7% by weight hydroxypropyl methylcellulose (Pharmacoat 606) were used in the binder solution instead of 15% by weight polyester.

[0060] Example 3 A cigarette filter was manufactured in the same manner as in Example 1, except that 3% polyester and 7% polyvinylpyrrolidone (K25) were used in the binder solution instead of 15% polyester by weight.

[0061] Comparative Example 1 Tobacco filters were manufactured without spraying a binder solution onto lyocell.

[0062] Experimental example Experimental Example 1: Evaluation of the hardness of cigarette filters The hardness of the tobacco filters produced by Examples 1-3 and Comparative Example 1 was measured. Furthermore, to measure the degree to which the tobacco filters disintegrated due to moisture, approximately 20 μl (22% by weight based on lyocell) of water was injected into each tobacco filter using a syringe, and the hardness of the tobacco filter was measured after approximately 5 minutes. Specifically, the hardness of the tobacco filters was measured using a filter hardness tester (Filtrona DHT 200). TM ) and the following calculation formula 1 were used for the measurement.

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

[0064] Here, D is the filter diameter, and a is the distance (in mm) that the filter descends (is pressed) when a 300g weight is applied.

[0065] [Table 1] *Moisture decay rate (%) = (1 - D2 / D1) × 100 (Here, D1 represents the hardness (%) before water injection, and D2 represents the hardness (%) after water injection.)

[0066] According to Table 1, when the binder solution contained polyester (Examples 1-3), the hardness before water injection was 85% or higher, specifically 90% or higher, and the hardness after water injection was 80% or higher, specifically 85% or higher, demonstrating 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] From the results above, the hardness after water injection is a value related to the minimum hardness until the smoker finishes smoking, and when polyester is included as a binder (Examples 1-3), the hardness of 80% or more can be maintained until the smoker finishes smoking, so the smoker does not feel that the structure of the cigarette filter is collapsing during smoking. Nevertheless, when polyester alone or a combination binder of polyester and hydroxypropyl methylcellulose is used (Examples 1 and 2), the degree of water disintegration is low, at 7% or less, specifically 6% or less, so the change in the tactile sensation of the cigarette filter felt by the smoker during smoking is even less.

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

[0069] Experimental Example 2: Evaluation of the viscosity and adhesive strength of the 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 apparatus 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 hydroxypropyl methylcellulose and 90% by weight water) to a nonwoven fabric, laminating it with 100 gsm art paper, drying it, and then measuring it using a tensile strength machine (Tinius Olsen, Universal Testing Machine 10ST series).

[0070] [Table 2]

[0071] According to Table 2, the polyester contained in the binder solution exhibited high adhesive strength, even to the point of destroying the adherend during drying, despite being a substance with very low viscosity. Binder solutions containing polyester have low viscosity, can be easily dispersed and uniformly distributed in target materials such as lyocell tow, and exhibit excellent adhesive strength after drying, making them suitable for imparting functionalities such as hardness to lyocell tow.

[0072] Although the embodiments have been described above with limited examples and drawings, a person with ordinary skill in the art can make various modifications and variations from the above description. For example, the described technique may be performed in a different order than described, and / or the components of the described system, structure, apparatus, circuit, etc. may be combined or assembled in a different manner than described, or substituted or replaced by other components or equivalents, and the appropriate results may still be achieved. [Explanation of Symbols]

[0073] 10 Smoking substance section 20 Filter section 30a Smoking substance wrapper 30b Filter section wrapper 40 Chip Paper 100 Smoking items

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 polyester is a copolymer of an aromatic monomer and an aliphatic monomer. 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 aromatic monomer is a dicarboxylic acid having a C5 to C12 allylene group or a heteroalylene group.

7. The tobacco filter according to any one of claims 1 to 3, wherein the aliphatic monomer is a diol having a C1-C4 alkylene group, a dicarboxylic acid having a C2-C12 alkylene group, or a combination thereof.

8. 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.

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

10. The tobacco filter according to claim 9, wherein the weight ratio of polyester to hydroxypropyl methylcellulose or polyvinylpyrrolidone in the binder is 1:1 to 1:3.

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