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(11) | EP 4 378 329 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
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| (54) | CIGARETTE FILTER INCLUDING LYOCELL TOW |
| (57) A cigarette filter which includes lyocell tow made of a plurality of lyocell fibers
and a binder configured to bond the lyocell fibers to each other and has a hardness
of 85% or higher is provided. According to one embodiment of the present disclosure,
the cigarette filter has a hardness of 80% or higher even 5 minutes after 20 parts
by weight to 25 parts by weight of water is added thereto based on 100 parts by weight
of the lyocell tow. According to one embodiment of the present disclosure, the cigarette
filter has a degree of collapse due to moisture of 7% or lower. According to one embodiment
of the present disclosure, the cigarette filter overcomes existing, material-related
problems of lyocell tow and has a high hardness and a low degree of collapse due to
moisture. |
[Technical Field]
[0001] The present disclosure relates to a cigarette filter including lyocell tow, and more particularly, to a cigarette filter which includes lyocell tow made of a plurality of lyocell fibers and a binder configured to bond the lyocell fibers to each other and has an excellent hardness of 85% or higher.
[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0173488, filed on December 7, 2021, the disclosure of which is incorporated herein by reference in its entirety.
[Background Art]
[0003] Generally, in order to manufacture a cigarette, first, various types of tobacco leaves are mixed and processed to have a desired flavor and taste. Then, the processed tobacco leaves are cut to produce cut tobacco leaves, and the cut tobacco leaves are wrapped by cigarette paper to produce a filter-free cigarette. Next, a filter is attached to the filter-free cigarette as necessary.
[0004] The cigarette paper may be produced using flax, wood pulp, and the like, and combustibility and the taste of tobacco are required to be maintained during burning of the cigarette. A cigarette filter may include activated carbon, a flavoring material, and the like, may be made of a mono-filter or a multi-filter, and is wrapped by cigarette filter wrapping paper. A cut tobacco leaf portion and the cigarette filter may be connected by tipping paper, and the tipping paper may include fine holes.
[0005] General cigarette filters use cellulose acetate tow in which cellulose extracted from wood pulp is acetylated. In recent years, in order to preserve the natural environment and reduce costs, development of eco-friendly materials that can replace cellulose acetate is progressing. For example, development of tow using lyocell fibers in which the cellulose itself is fiberized, unlike in cellulose acetate, is progressing.
[0006] In cigarette filters, hardness is an important indicator relating to the needs of consumers and the workability of manufacturing cigarettes. In a case in which a cigarette filter is manufactured using tow, which is a bundle of fiber strands, the hardness of the cigarette filter is low and thus is unsuitable, and it is necessary to improve the hardness of the tow to a certain level or higher for the tow to be utilized as the cigarette filter. Examples of a method of improving the hardness of the filter include a method using a hardener and a method using a plasticizer. The method using a hardener is a method in which the fiber strands are bonded using a binder-like material to impart hardness to the filter, thus hardening the filter. The method using a plasticizer is a method in which the fibers themselves are partially dissolved or plasticized using a specific material to form bonding points between the fibers and then the fibers are plasticized.
[0007] The conventional cellulose acetate imparts hardness to cigarette filters using a principle in which a plasticizer (triacetin or triethyl citrate) is utilized to partially dissolve fiber strands to harden the fiber strands. However, since there is currently no plasticizer for lyocell fibers, it is essential to develop a hardness improver that suits the lyocell fibers.
[0008] The lyocell fibers are known as a hydrophilic material unlike cellulose acetate which is hydrophobic. Accordingly, even when the hardness of the lyocell fibers is improved using a hardness improver to apply the lyocell fibers to cigarette filters, preventing a structure of the cigarette from collapsing due to moisture or the like supplied from a smoker or the like during smoking should also be considered as an important matter.
[0009] The inventors of the present disclosure have completed the present disclosure after recognizing the above-described technical challenge with regards to the lyocell fibers and carrying out continuous research on lyocell tow with excellent functionality that is suitable for application to cigarette filters.
[Related Art Document]
[Patent Document]
[Disclosure]
[Technical Problem]
[0011] The present disclosure is directed to providing a cigarette filter including lyocell tow as an eco-friendly material and capable of addressing basic material-related problems, such as a low hardness and a high degree of collapse due to moisture, of the lyocell tow.
[Technical Solution]
[0012] A first aspect of the present disclosure provides a cigarette filter which includes lyocell tow made of a plurality of lyocell fibers and a binder configured to bond the lyocell fibers to each other and has a hardness of 85% or higher.
[0013] In one embodiment of the present disclosure, the cigarette filter may have a hardness of 80% or higher even 5 minutes after 20 parts by weight to 25 parts by weight of water is added thereto based on 100 parts by weight of the lyocell tow.
[0014] In one embodiment of the present disclosure, the cigarette filter may have a degree of collapse due to moisture of 7% or lower.
[0016] In one embodiment of the present disclosure, the polyester may be a copolymer of an aromatic monomer and an aliphatic monomer.
[0017] In one embodiment of the present disclosure, the polyester may have a viscosity of lower than 5 cps at 40 °C with respect to an aqueous polyester solution with a polyester concentration of 15 wt%.
[0018] In one embodiment of the present disclosure, the aromatic monomer may be a dicarboxylic acid having a C5-C12 arylene group or heteroarylene group.
[0019] In one embodiment of the present disclosure, the aliphatic monomer may be a diol having a C1-C4 alkylene group, a dicarboxylic acid having a C2-C12 alkylene group, or a combination thereof.
[0020] In one embodiment of the present disclosure, the polyester may be included at 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the lyocell tow.
[0021] In one embodiment of the present disclosure, the binder may further include hydroxypropyl methylcellulose or polyvinylpyrrolidone.
[0022] In one embodiment of the present disclosure, in the binder, a weight ratio of polyester and hydroxypropyl methylcellulose or polyvinylpyrrolidone may be in a range of 1:1 to 1:3.
[Advantageous Effects]
[0023] While including lyocell tow which is an eco-friendly material, a cigarette filter according to one embodiment of the present disclosure overcomes existing, material-related problems of lyocell tow and has an excellent hardness of 90% or higher.
[0024] Also, the cigarette filter has adequate durability against moisture and can minimize a change in hardness to 6% or less even while a smoker smokes a smoking article and thus can maintain an excellent hardness of 85% or higher even until the smoking article leaves the smoker's hand after the smoker is done smoking.
[Description of Drawings]
[0025] FIG. 1 is a view illustrating a schematic configuration of a smoking article according to one embodiment of the present disclosure.
[Best Mode of the Invention]
[0026] Hereinafter, embodiments will be described in detail with reference to the illustrative drawings. In assigning reference numerals to components of each drawing, it should be noted that the same reference numerals are assigned to the same components wherever possible even when the components are illustrated in different drawings. Also, in describing the embodiments, when detailed description of a known related configuration or function is considered to hinder the understanding of the embodiments, the detailed description thereof will be omitted.
[0027] Also, in describing components of the embodiments, terms such as first, second, A, B, (a), and (b) may be used. Such terms are only for distinguishing one component from another component, and the essence, order, sequence, or the like of the corresponding component is not limited by the terms. In a case in which a certain component is described as being "connected," "coupled," or "linked" to another component, it should be understood that, although the component may be directly connected or linked to the other component, still another component may also be "connected," "coupled," or "linked" between the two components.
[0028] A component including a common function with a component included in any one embodiment will be described using the same name in another embodiment. Unless the context clearly indicates otherwise, description made in any one embodiment may apply to another embodiment and a repeated description will be omitted.
[0029] In this specification, a "smoking article" may refer to anything capable of generating an aerosol, such as tobacco (cigarettes) and cigars. The smoking article may include an aerosol-generating material or an aerosol-forming substrate. Also, the smoking article may include a solid material based on tobacco raw materials, such as reconstituted tobacco leaves, cut tobacco leaves, and reconstituted tobacco. A smoking material may include a volatile compound. The smoking article may include several segments each having functionality, and such segments are indicated as "... portions." In this specification, the smoking article may not only be a combustion-type cigarette but also be a heating-type cigarette used together with an aerosol generation device (not illustrated) such as an electronic cigarette device.
[0030] In this specification, the terms "upstream" and "downstream" are terms used to indicate relative positions of segments constituting a smoking article, based on a direction in which a user draws air using the smoking article. The smoking article includes an upstream end portion (that is, a portion through which air enters) and a downstream end portion (that is, a portion through which air exits) opposite the upstream end portion. When using the smoking article, the user may hold the downstream end portion of the smoking article in his/her mouth. The downstream end portion is disposed downstream of the upstream end portion. Meanwhile, the term "end portion" may also be replaced with the term "end."
[0031] The present disclosure relates to a cigarette filter that may be applied to a smoking article. According to one embodiment of the present disclosure, the cigarette filter includes lyocell tow made of a plurality of lyocell fibers and a binder configured to bond the lyocell fibers to each other. The lyocell fibers are eco-friendly fibers made of 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 disclosure, the lyocell fibers may have a size in a range of 1.0 denier to 12.0 denier. According to one embodiment of the present disclosure, the lyocell fiber bundle constituting the lyocell tow may have a size in a range of 15,000 denier to 45,000 denier. A binder suitable for the lyocell fibers may be mixed with a solvent to prepare a binder solution, and the binder solution may be sprayed on the lyocell tow and then dried so that the lyocell tow is formed with a structure having a certain level of hardness or higher.
[0032] The cigarette filter including the lyocell tow according to one embodiment of the present disclosure has excellent hardness due to bonding using the binder and also has excellent durability against moisture. According to one embodiment of the present disclosure, the cigarette filter has a hardness of 85% or higher. Specifically, the hardness of the cigarette filter may be 85% or higher, 86% or higher, 87% or higher, 88% or higher, 89% or higher, 90% or higher, 91% or higher, or 91.5% or higher. The hardness of the cigarette filter is a numerical value of a degree to which a diameter of the cigarette filter is maintained when the cigarette filter is pressed with a force of a certain magnitude in a vertical direction. Specifically, the hardness of the cigarette filter may be calculated by Equation 1 below.
[0033] Here, D represents a filter diameter (mm), and a represents a distance (mm) the filter moves downward (is pressed) due to a 300-g weight. Measured values necessary to calculate the hardness of the cigarette filter may be obtained using a device generally used in the art. For example, Filtrona's DHT 200™ may be used. In measuring the hardness, the force applied takes into consideration an actual force applied when a smoker grips a cigarette. The hardness value of 85% or higher that is obtained through the cigarette filter according to one embodiment of the present disclosure has technical significance in that it shows hardness can be secured at a level that the conventional cigarette filter made of cellulose acetate can be replaced with the cigarette filter made of the lyocell tow which is an eco-friendly material.
[0034] The hardness of the cigarette filter indicates a hardness when a smoker initially grips a cigarette to smoke the cigarette, and such hardness does not ensure that the hardness of the cigarette filter is maintained until the end of smoking by the smoker. A considerable amount of moisture may enter the cigarette filter during smoking by the smoker, and the filter including the lyocell tow may have at least a certain level of durability against moisture so that it is easy to maintain the initial hardness. The lyocell fibers are known as a hydrophilic material unlike cellulose acetate which is hydrophobic, and thus it is not easy to maintain the hardness of the lyocell fibers due to characteristics of the material. According to one embodiment of the present disclosure, the cigarette filter has a hardness of 80% or higher even 5 minutes after adding 20 parts by weight to 25 parts by weight of water based on 100 parts by weight of the lyocell tow. Specifically, the hardness of the cigarette filter after water is added thereto may be 80% or higher, 81% or higher, 82% or higher, 83% or higher, 84% or higher, 85% or higher, or 86% or higher. The hardness of the cigarette filter after water is added thereto is measured using the same method as before water is added. Checking the durability against moisture by measuring the hardness of the cigarette filter after adding water thereto takes into consideration a change in the hardness of the cigarette filter until the end of smoking by the smoker. The amount of added water or the elapsed time takes into consideration the actual smoking by the smoker. The amount of moisture included in the cigarette filter after smoking by the smoker is actually around 8 parts by weight on average, and adding 20 parts by weight to 25 parts by weight of water is a harsher condition compared to the actual smoking situation. The cigarette filter according to one embodiment of the present disclosure can maintain an excellent hardness of 85% or higher while the smoker grips the cigarette during smoking.
[0035] A degree of collapse due to moisture, which indicates an amount of change in the hardness according to addition of water, may be calculated by comparing the hardness before adding water and the hardness after adding water. According to one embodiment of the present disclosure, the cigarette filter may have a degree of collapse due to moisture of 7% or lower. Specifically, the degree of collapse due to moisture of the cigarette filter may be 7% or lower, 6.5% or lower, 6% or lower, 5.5% or lower, or 5% or lower. The degree of collapse due to moisture is basically based on the hardness before adding water and the hardness after adding water and may be calculated by Equation 2 below.
[0036] Here, D1 represents a hardness before adding water (%), and D2 represents a hardness after adding water (%). The degree of collapse due to moisture being low may be meaningful in that the hardness after adding water may be high, but from the smoker's point of view, there is also technical significance in that a change in the sense of touch when touching the cigarette filter is little during smoking.
[0037] According to one embodiment of the present disclosure, the binder includes polyester. The polyester has a function of bonding the lyocell fibers to impart hardness to the lyocell tow. Specifically, the polyester is a synthetic resin formed by a reaction between a polyfunctional organic acid and a polyhydric alcohol and has appropriate resistance against water and various compounds. According to one embodiment of the present disclosure, the polyester has a weight-average molecular weight in a range of 1,000 to 50,000, specifically in a range of 1,500 to 30,000, and more specifically in a range of 2,000 to 10,000. In a case in which the polyester has a molecular weight below the above range, resistance against water or the like may be reduced, and in a case in which the polyester has a molecular weight above the above range, it is not easy for the polyester to be appropriately dispersed in the lyocell tow.
[0038] According to one embodiment of the present disclosure, 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, such that, the polyester including the aromatic monomer and the aliphatic monomer may easily adhere to other components such as the lyocell fibers and add functionality as a binder. The aromatic monomer may be a polyfunctional organic acid or polyhydric alcohol, and likewise, the aliphatic monomer may be a polyfunctional organic acid or polyhydric alcohol. The polyester exhibits low viscosity in an aqueous solution state and thus is easy to spray and apply in the aqueous solution state. According to one embodiment of the present disclosure, the viscosity of the polyester at 40 °C with respect to an aqueous polyester solution with a polyester concentration of 15 wt% may be lower than 5 cps, 4 cps or lower, 3 cps or lower, or 2 cps or lower. Here, the aqueous polyester solution with a polyester concentration of 15 wt% indicates a solution obtained by mixing 15 wt% polyester and 85 wt% water.
[0039] According to one embodiment of the present disclosure, the aromatic monomer is a dicarboxylic acid having a C5-C12 arylene group or heteroarylene group. As an example, the dicarboxylic acid having a C5-C12 arylene group or heteroarylene group may be phthalic acid, terephthalic acid, or isophthalic acid. According to one embodiment of the present disclosure, 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. As an example, the diol having a C1-C6 alkylene group may be ethylene glycol, and the dicarboxylic acid having a C2-C12 alkylene group may be sebacic acid. For polyester that can be formed by a condensation reaction between a carboxylic acid group and a hydroxyl group at a 1:1 ratio, as a monomer having a carboxylic acid group, the dicarboxylic acid having a C5-C12 arylene group or heteroarylene group, the dicarboxylic acid having a C2-C12 alkylene group, or a combination thereof may be used, and as a monomer having a hydroxyl group, the diol having a C1-C6 alkylene group may be used. The arylene group, heteroarylene group, or alkylene group is present in a substituted or unsubstituted state, and in the case of the substituted state, a substituent generally known in the art, such as a C1-C4 alkyl group, a C1-C4 alkoxy group, or a halogen group, may be substituted in the main chain of the arylene group, heteroarylene group, or alkylene group.
[0040] The polyester may be included in a solvent such as water and applied in the form of a binder solution to the lyocell tow, and then drying may be performed so that the solvent is partially or entirely removed. Even after drying, the polyester is positioned in between the lyocell fibers and improves the hardness of the lyocell tow. According to one embodiment of the present disclosure, the polyester is included at 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the lyocell tow. Specifically, the content of the polyester 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, or 2.5 parts by weight or less and may be in a range of 0.1 parts by weight to 5 parts by weight, 0.2 parts by weight to 4 parts by weight, or 0.3 parts by weight to 3 parts by weight. When applied within the above range, the polyester may increase the hardness of the lyocell tow to an appropriate level while not degrading the basic function of the lyocell tow as a filter.
[0041] The binder may include another binder component along with polyester. As the other binder component, for example, hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA), polyvinyl acetate (PVAc), or polyvinylpyrrolidone (PVP) may be used. According to one embodiment of the present disclosure, the binder may further include HPMC or PVP, specifically HPMC, along with polyester. In terms of functionality as a binder, the binder may have a synergistic effect when used along with polyester. According to one embodiment of the present disclosure, in the binder, a weight ratio of polyester and HPMC or PVP is in a range of 1:1 to 1:3. Specifically, the weight ratio of polyester and HPMC or PVP may be in a range of 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 along with another binder component, the content ratio may be controlled to be within the above range to obtain a synergistic effect through the combination.
[0042] The cigarette filter described above may be produced through the following production method. The production method includes using lyocell fibers to produce lyocell tow, mixing a binder and a solvent to prepare a binder solution, performing drying after spraying the binder solution on the lyocell tow, and wrapping the dried lyocell tow with wrapping paper to produce a cigarette filter. Since the production method basically relates to a method of producing the cigarette filter described above, description of the content described in detail above will be omitted, and features of the production method will be described in more detail below.
[0043] First, a plurality of lyocell fibers are used to produce lyocell tow. The produced lyocell tow has the shape of a bundle formed by cross-linking adjacent lyocell fibers. Here, inflating the tow through blooming is additionally performed. When the tow is inflated through the blooming operation, a binder solution which is sprayed afterwards may easily penetrate between the lyocell fibers constituting the lyocell tow.
[0044] Then, a binder and a solvent are mixed to prepare a binder solution. The binder solution is a substance sprayed on the lyocell tow to improve functionality, such as hardness, of the lyocell tow. Since some components of the binder solution may be lost through the drying process after the binder solution is sprayed, the composition of the binder solution may differ from the composition of the components constituting the cigarette filter. Since the binder may be embodied according to the above-described content, and components of the binder are not particularly lost even after drying, the amount of the binder supplied to the lyocell tow through spraying remains almost unchanged even in the final cigarette filter. The solvent includes water, and some of the water is lost in the drying process. In a case in which the binder solution is prepared using only the binder and water, the content obtained by excluding the content of the binder from the entire content of the binder solution is the content of water. According to one embodiment of the present disclosure, the binder is included at 5 parts by weight to 40 parts by weight based on 100 parts by weight of the binder solution. Specifically, the content of the binder 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, or 20 parts by weight or less and may be in a range of 5 parts by weight to 40 parts by weight, 7 parts by weight to 30 parts by weight, or 10 parts by weight to 20 parts by weight. When the binder solution is formed with the content of the binder within the above range, it is easy to spray and apply the binder solution onto the lyocell tow.
[0045] The binder solution prepared according to the above-described content is sprayed on the lyocell tow. The binder solution may be sprayed on the lyocell tow to an extent that material-related problems, such as low hardness, of the lyocell tow can be addressed while not degrading the basic function of the lyocell tow as a filter. According to one embodiment of the present disclosure, 5 parts by weight to 30 parts by weight of the binder solution is sprayed on the lyocell tow, based on 100 parts by weight of the lyocell tow. Specifically, the amount of sprayed binder solution 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, 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 in a range of 5 parts by weight to 30 parts by weight, 7 parts by weight to 24 parts by weight, or 10 parts by weight to 20 parts by weight. When the binder solution is sprayed within the above range, the functionality, such as hardness, of the lyocell tow can be improved. A method of spraying the binder solution may be a method generally used in the art and is not particularly limited. For example, nozzle spraying, brush spraying, electrospraying, or the like may be utilized to spray the binder solution.
[0046] After spraying the binder solution on the lyocell tow, the lyocell tow is dried to reduce the amount of moisture and secure hardness. A method of drying the lyocell tow may be a method generally used in the art and is not particularly limited. For example, drying may be performed so that the amount of initially sprayed moisture is reduced 30% or more.
[0047] The dried lyocell tow is wrapped with wrapping paper to produce a cigarette filter. Using a mechanical roll, a cutter, or the like, the lyocell tow may be processed into dimensions suitable for application to the cigarette filter as necessary.
[0048] The cigarette filter described above may be applied to a smoking article. FIG. 1 is a view illustrating a schematic configuration of a smoking article according to one embodiment of the present disclosure. A smoking article 100 includes a smoking material portion 10 and a filter portion 20, and the cigarette filter described above is applied to the filter portion 20 of the smoking article 100. In the smoking article 100, the smoking material portion 10 is disposed upstream of the filter portion 20.
[0049] The smoking material portion 10 may be filled with a smoking material such as raw tobacco leaves, reconstituted tobacco leaves, or a mixture of tobacco leaves and reconstituted tobacco leaves. The processed smoking material may be filled in the form of sheets or cut tobacco leaves in the smoking material portion 10. The smoking material portion 10 may have the form of a longitudinally extending rod whose length, circumference, and diameter are not particularly limited but may be controlled to sizes generally used in the art in consideration of the amount of filled smoking material, preferences of a user, or the like. The smoking material portion 10 may include at least one aerosol-generating material among glycerin, propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and oleyl alcohol. The smoking material portion 10 may contain other additives such as a flavoring agent, a wetting agent, and/or an acetate compound. The aerosol-generating material and the additives may be contained in the smoking material.
[0050] The filter portion 20 is disposed downstream of the smoking material portion 10 to serve as a filter through which an aerosol material generated in the smoking material portion 10 passes right before being inhaled by the user. The filter portion 20 may be made of various materials or in various forms. The filter portion 20 according to one embodiment of the present disclosure basically includes the above-described cigarette filter including lyocell tow in which a plurality of lyocell fibers are bonded by a binder. The cigarette filter including the lyocell tow may partially or entirely replace the filter portion 20 of the conventional smoking article, and in a case in which the cigarette filter partially replaces the filter portion 20, a conventionally-used filter material may be used together. For example, as the conventional filter material, a cellulose acetate filter, a hollow tubular filter, or the like may be used.
[0051] The filter portion 20 is illustrated as a mono filter formed of a single filter in FIG. 1, but the present disclosure is not limited thereto. For example, the filter portion 20 may be provided as a dual filter which includes two acetate filters, a triple filter, or the like in order to increase filter efficiency. Also, although not illustrated, a crushable capsule (not illustrated), which has a structure in which a flavor-containing liquid filled therein is wrapped by a film, may be included inside the filter portion 20.
[0052] The outside of the smoking material portion 10 and the filter portion 20 may be wrapped with a wrapper 30a or 30b.
[0053] The smoking material portion 10 may be wrapped with a smoking material portion wrapper 30a. Some of the cigarette smoke generated in the combustion process of a general smoking material portion 10 is released into the atmosphere through the smoking material portion wrapper 30a before passing through a cigarette filter, and such sidestream smoke causes discomfort to non-smokers who are exposed to secondhand smoke. Various attempts have been made to reduce sidestream smoke, including adding a filler such as magnesium oxide, titanium oxide, cerium oxide, aluminum oxide, calcium carbonate, or zirconium carbonate to conventional cigarette paper, but when the sidestream smoke is reduced by simply applying the filler, a tobacco smoke taste may be degraded, combustion may be interrupted, ash integrity may be degraded, or the like, and there is difficulty in addressing such problems through an appropriate combination of materials in the filler. In order to prevent the degradation of a tobacco smoke taste and ash integrity and the interruption of combustion while reducing sidestream smoke, a filler in which magnesium oxide (MgO and/or Mg(OH)2) and calcium carbonate (CaCO3) are mixed is applied to the smoking material portion wrapper 30a according to one embodiment of the present disclosure.
[0054] The filter portion 20 may be wrapped with a filter portion wrapper 30b. The filter portion wrapper 30b may be manufactured using grease-resistant wrapping paper, and an aluminum foil may be further included at an inner surface of the filter portion wrapper 30b.
[0055] The smoking material portion 10 wrapped with the smoking material portion wrapper 30a and the filter portion 20 wrapped with the filter portion wrapper 30b may be wrapped together by tipping paper 40. As illustrated in FIG. 1, the tipping paper 40 may wrap around at least a portion (for example, a partial downstream area) of the smoking material portion wrapper 30a and an outer periphery of the filter portion wrapper 30b. In other words, the filter portion 20 and at least a portion of the smoking material portion 10 may be further wrapped with the tipping paper 40 and physically combined with each other. According to one embodiment of the present disclosure, the tipping paper 40 may be made of nonporous wrapping paper not treated to be grease-resistant, but the present disclosure is not limited thereto. Also, the tipping paper 40 may include an incombustible material and thus prevent a phenomenon in which the filter portion 20 is burned, but the present disclosure is not limited thereto.
[Modes of the Invention]
[0056] Hereinafter, the configurations of the present disclosure and the advantageous effects according thereto will be described in more detail using examples and a comparative example. However, the examples are merely for describing the present disclosure in more detail, and the scope of the present disclosure is not limited by the examples.
Examples
Example 1
[0057] Using lyocell fibers each having a size of about 3.0 denier, lyocell tow in which a tow fiber bundle has a size of about 35,000 denier was produced. Also, a binder solution, which is a mixture of a binder and a solvent, was prepared. Specifically, the binder solution was prepared by adding 15 wt% polyester (a copolymer of phthalic acid and sebacic acid or ethylene glycol, weight-average molecular weight (Mw) = 3,000 to 6,000) to 85 wt% water based on the entire weight of the binder solution. The prepared binder solution was sprayed on the lyocell tow through nozzle spraying. The 15 wt% binder solution was sprayed based on the weight of the lyocell tow, and drying was performed. The dried lyocell tow was wrapped with wrapping paper to produce a cigarette filter having an axial length of about 108 mm and a circumference of about 24.20 mm.
Example 2
[0058] A cigarette filter was produced in the same manner as in Example 1, except that 3 wt% polyester and 7 wt% HPMC (Pharmacoat 606) were used in the binder solution, instead of 15 wt% polyester.
Example 3
[0059] A cigarette filter was produced in the same manner as in Example 1, except that 3 wt% polyester and 7 wt% PVP (K25) were used in the binder solution, instead of 15 wt% polyester.
Comparative Example 1
Experimental Examples
Experimental Example 1: Evaluation of hardness of cigarette filters
[0061] A hardness was measured for the cigarette filters produced according to Examples 1 to 3 and Comparative Example 1. Also, in order to measure a degree to which the cigarette filter collapses due to moisture, about 20 µl (22 wt% based on the lyocell tow) of water was added to each of the cigarette filters using a syringe, and then 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 measuring instrument (Filtrona's DHT 200™) and Equation 1 below.
[0062] Here, D represents a filter diameter, and a represents a distance (mm) the filter moves downward (is pressed) due to a 300-g weight.
[Table 1]
| Hardness before adding water (%) | Hardness after adding water (%) | Degree of collapse due to moisture (%) | |
| Example 1 | 91.5 | 86.1 | 5.9 |
| Example 2 | 91.5 | 87.0 | 4.9 |
| Example 3 | 94.5 | 86.5 | 8.5 |
| Comparative Example 1 | 84.7 | 77.4 | 8.6 |
[0063] (Here, D1 represents a hardness before adding water (%), and D2 represents a hardness after adding water (%).)
[0064] According to Table 1 above, in a case in which polyester was included in the binder solution (Examples 1 to 3), excellent hardness was exhibited. The hardness before adding water was 85% or higher, specifically 90% or higher, and the hardness after adding water was 80% or higher, specifically 85% or higher. According to Examples 2 and 3, excellent hardness was maintained even when the polyester was used in combination with other types of binders such as HPMC and PVP.
[0065] In the above results, the hardness after adding water is a numerical value relating to the minimum hardness until the end of smoking by a smoker, and since a hardness of 80% or higher can be maintained even until the end of smoking by a smoker in the case in which polyester is included as a binder (Examples 1 to 3), the smoker may not feel the structure of the cigarette filter collapsing during smoking. Nevertheless, in the case in which polyester is used alone as a binder or a combination of polyester and HPMC is used as a binder (Examples 1 and 2), the degree of collapse due to moisture is 7% or lower, specifically 6% or lower, and thus a change in the smoker's sense of touch when touching the cigarette filter may be even less during smoking.
[0066] On the other hand, in the case in which a binder solution such as polyester is not used (Comparative Example 1), it may be undesirable because a cigarette filter including lyocell tow is extremely vulnerable to moisture, and the structure of the cigarette filter may be changed not only during smoking but also during storage in harsh conditions with the presence of some moisture.
Experimental Example 2: Evaluation of viscosity and adhesive strength of binder solutions
[0067] The measured viscosity and adhesive strength of the binder solutions used in Examples 1 and 2 are shown in Table 2 below. The viscosity was measured using BrookField's Spindle No. 61 under a temperature condition of 40 °C. The adhesive strength was measured using a stretcher (Tinius Olsen's Universal Testing Machine 10ST series) after applying the binder solution of Example 1 (15 wt% polyester and 85 wt% water) and the binder solution of Example 2 (3 wt% polyester, 7 wt% HPMC, and 90 wt% water) to a nonwoven fabric, laminating coated paper having a basis weight of 100 gsm on the nonwoven fabric, and drying.
[Table 2]
| Viscosity (cps) | Adhesive strength (gf/mm2) | |
| Binder solution of Example 1 | 2 cps or lower | Unable to measure (material to which binder solution was adhered was destroyed) |
| Binder solution of Example 2 | 85 | Unable to measure (material to which binder solution was adhered was destroyed) |
[0068] According to Table 2 above, despite being a material with a very low viscosity, when dried, polyester included in the binder solutions exhibited an adhesive strength high enough to destroy a material to which the binder solutions were adhered. The binder solutions including polyester have a low viscosity and thus can be easily dispersed and evenly distributed in a material to which the binder solutions are applied, such as lyocell tow. Since the binder solutions including polyester exhibit excellent adhesive strength or the like after being dried, the binder solutions including polyester are suitable to improve functionality, such as hardness, of the lyocell tow.
[0069] The embodiments have been described above using only some examples and drawings, but those of ordinary skill in the art may make various modifications and changes to the embodiments from the above description. For example, appropriate results may be achieved even when operations described herein are performed in a different order from the method described herein, and/or components such as a system, a structure, a device, and a circuit described herein are coupled or combined in different forms from the method described herein or replaced or substituted with other components or their equivalents.
[Description of reference numerals]
1. A cigarette filter comprising:
lyocell tow made of a plurality of lyocell fibers; and
a binder configured to bond the lyocell fibers to each other,
wherein the cigarette filter has a hardness of 85% or higher.
2. The cigarette filter of claim 1, wherein the cigarette filter has a hardness of 80%
or higher even 5 minutes after 20 parts by weight to 25 parts by weight of water is
added thereto based on 100 parts by weight of the lyocell tow.
3. The cigarette filter of claim 2, wherein the cigarette filter has a degree of collapse
due to moisture of 7% or lower.
4. The cigarette filter of claim 1, wherein the binder includes polyester.
5. The cigarette filter of claim 4, wherein the polyester is a copolymer of an aromatic
monomer and an aliphatic monomer.
6. The cigarette filter of claim 4, wherein the polyester has a viscosity of lower than
5 cps at 40 °C with respect to an aqueous polyester solution with a polyester concentration
of 15 wt%.
7. The cigarette filter of claim 5, wherein the aromatic monomer is a dicarboxylic acid
having a C5-C12 arylene group or heteroarylene group.
8. The cigarette filter of claim 5, 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.
9. The cigarette filter of claim 4, wherein the polyester is included at 0.1 parts by
weight to 5 parts by weight based on 100 parts by weight of the lyocell tow.
10. The cigarette filter of claim 4, wherein the binder further includes hydroxypropyl
methylcellulose or polyvinylpyrrolidone.
11. The cigarette filter of claim 10, wherein, in the binder, a weight ratio of polyester
and hydroxypropyl methylcellulose or polyvinylpyrrolidone is in a range of 1:1 to
1:3.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description