CIGARETTE FILTER COMPRISING LYOCELL TOW, AND MANUFACTURING METHOD THEREOF

Abstract

 A cigarette filter which includes lyocell tow made of a plurality of lyocell fibers, a binder configured to bond the lyocell fibers to each other, and a solvent dispersed in an inner space of the cigarette filter including the lyocell tow, wherein the solvent includes a polyhydric alcohol, is provided. According to one embodiment of the present disclosure, the polyhydric alcohol is a diol having a C1-C4 alkylene group. The cigarette filter according to one embodiment of the present disclosure overcomes the existing material-related problems of lyocell tow and has excellent hardness.

Description

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, a binder configured to bond the lyocell fibers to each other, and a solvent dispersed in an inner space of the cigarette filter including the lyocell tow, wherein the solvent includes a polyhydric alcohol.

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0173493, 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 a 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 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

[0009] 

a. (Patent Document 1) Korean Unexamined Patent Application Publication No. 10-2015-0116612

Disclosure

Technical Problem

[0010] b. 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 low processability during a process for securing the hardness, of the lyocell tow.

Technical Solution

[0011] A first aspect of the present disclosure provides a cigarette filter which includes lyocell tow made of a plurality of lyocell fibers, a binder configured to bond the lyocell fibers to each other, and a solvent dispersed in an inner space of the cigarette filter including the lyocell tow, wherein the solvent includes a polyhydric alcohol.

[0012] In one embodiment of the present disclosure, the polyhydric alcohol may be a diol having a C1-C4 alkylene group.

[0013] In one embodiment of the present disclosure, the polyhydric alcohol may be included at 0.5 parts by weight to 25 parts by weight based on 100 parts by weight of the lyocell tow.

[0014] In one embodiment of the present disclosure, the binder may be hydroxypropyl methylcellulose, hydroxypropyl cellulose, polyvinyl alcohol, ethylene vinyl acetate, polyvinyl acetate, polyvinylpyrrolidone, polyester, or a combination thereof.

[0015] In one embodiment of the present disclosure, the binder may be included at 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the lyocell tow.

[0016] In one embodiment of the present disclosure, the solvent may further include a monohydric alcohol which is methanol, ethanol, propanol, or a combination thereof.

[0017] A second aspect of the present disclosure provides a method of producing the above-described cigarette filter, the method including using a plurality of lyocell fibers to produce lyocell tow, mixing a binder and a solvent to prepare a binder solution, storing the lyocell tow to allow the lyocell fibers to be bonded to each other by the binder after spraying the binder solution on the lyocell tow, and wrapping the lyocell tow, in which the lyocell fibers are bonded by the binder, with wrapping paper to produce the cigarette filter, wherein the solvent includes a polyhydric alcohol.

[0018] In one embodiment of the present disclosure, the polyhydric alcohol may be included at 5 parts by weight to 50 parts by weight based on 100 parts by weight of the binder solution.

[0019] In one embodiment of the present disclosure, the solvent may further include a monohydric alcohol.

[0020] In one embodiment of the present disclosure, the monohydric alcohol may be methanol, ethanol, propanol, or a combination thereof.

[0021] In one embodiment of the present disclosure, the monohydric alcohol may be included at 5 parts by weight to 60 parts by weight based on 100 parts by weight of the binder solution.

[0022] In one embodiment of the present disclosure, the binder solution may be sprayed on the lyocell tow in an amount of 5 parts by weight to 30 parts by weight based on 100 parts by weight of the lyocell tow.

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 the existing material-related problems of lyocell tow and has excellent hardness.

[0024] Unlike other cigarette filters to which lyocell tow is applied, since the excellent hardness of the cigarette filter according to one embodiment of the present disclosure can be implemented even when drying is not performed for a long time at high temperature, processability in the production of the cigarette filter can be increased, and thus productivity can be improved.

[0025] The cigarette filter according to one embodiment of the present disclosure includes a polyhydric alcohol, and the polyhydric alcohol may not only basically improve the hardness of the cigarette filter together with the binder, but also serve as a release agent during roll processing in a cigarette filter production process, thus reducing product defects and improving workability.

Description of Drawings

[0026] 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

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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."

[0032] 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, a binder configured to bond the lyocell fibers to each other, and a solvent dispersed in an inner space of the cigarette filter including the lyocell tow. 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 so that the lyocell tow is formed with a structure having a certain level of hardness or higher. Even a long time after the binder solution is sprayed, the binder and some components of the solvent may be included in the final cigarette filter without leaking.

[0033] The binder included in the cigarette filter bonds the lyocell fibers to each other to impart a certain level of hardness or higher to the lyocell tow. Any ordinary material known in the art that is suitable for application to the lyocell tow may be freely used as the binder. According to one embodiment of the present disclosure, hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA), polyvinyl acetate (PVAc), polyvinylpyrrolidone (PVP), polyester, or a combination thereof may be used as the binder. Specifically, HPMC, polyester, or a combination thereof may be used as the binder.

[0034] 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 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.

[0035] 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.

[0036] The binder may be applied to the lyocell tow in the form of a binder solution together with the solvent, and even when the lyocell tow is dried or left for a long time after the binder is applied thereto, the binder is positioned in between the lyocell fibers without leaking and improves the hardness of the lyocell tow. According to one embodiment of the present disclosure, the binder 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 binder 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 binder 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.

[0037] The solvent included in the cigarette filter is basically included in the binder solution to disperse the binder, and some of the solvent is removed when the lyocell tow is dried or left for a long time after the binder solution is sprayed on the lyocell tow. The unremoved solvent is positioned as one component inside the cigarette filter including the lyocell tow and imparts additional functionality to the cigarette filter. The solvent remaining in the cigarette filter includes a polyhydric alcohol. Here, the polyhydric alcohol refers to a compound including two or more hydroxyl groups. The polyhydric alcohol serves as a release agent during processing of the lyocell tow using a mechanical roll or the like, which is performed to apply the lyocell tow to the cigarette filter. Specifically, in a case in which the lyocell tow is processed using a mechanical roll or the like without a release agent, a phenomenon in which the lyocell tow is rolled around the mechanical roll or the like due to the adhesive strength of the binder or the like may occur. With the lyocell tow including a polyhydric alcohol, the occurrence of such a phenomenon may be reduced, and processability may be increased. Also, when applied to the lyocell tow, the polyhydric alcohol is positioned in between the lyocell fibers together with the binder and helps improve the hardness of the lyocell tow within a short time even when drying is not performed for a long time at a particularly high temperature. Accordingly, in a case in which the solvent including the polyhydric alcohol is used, since the drying time can be significantly shortened, processability in the production of the cigarette filter can be increased.

[0038] According to one embodiment of the present disclosure, the polyhydric alcohol is a diol having a C1-C4 alkylene group. The diol refers to a compound having two hydroxyl groups and is also referred to as a glycol. The two hydroxyl groups may be connected by the C1-C4 alkylene group, and here, the carbon number of the alkylene group refers to the number of carbons directly connected between the two hydroxyl groups. The 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-C3 alkyl group, a C1-C3 alkoxy group, or a halogen group, may be substituted in the main chain of the alkylene group. According to one embodiment of the present disclosure, the polyhydric alcohol may be propylene glycol. The propylene glycol is a polyhydric alcohol having a chain of an appropriate length and may be a more desirable compound due to having the above-described functionality.

[0039] The polyhydric alcohol may be applied to the lyocell tow in the form of a binder solution together with the binder and other solvents. The polyhydric alcohol remains unchanged in the lyocell tow or the cigarette filter to which the lyocell tow is applied even before and after drying is performed, thus imparting the above-described functionality, such as improving the processability as well as the hardness. According to one embodiment of the present disclosure, the polyhydric alcohol is included at 0.5 parts by weight to 25 parts by weight based on 100 parts by weight of the lyocell tow. Specifically, the content of the polyhydric alcohol may be 0.5 parts by weight or more, 0.6 parts by weight or more, 0.7 parts by weight or more, 0.8 parts by weight or more, 0.9 parts by weight or more, 1 part by weight or more, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less and may be in a range of 0.5 parts by weight to 10 parts by weight, 0.7 parts by weight to 7 parts by weight, or 1 part by weight to 5 parts by weight. When applied within the above range, the polyhydric alcohol may impart additional functionality to the cigarette filter while not degrading the basic function of the lyocell tow as a filter.

[0040] According to one embodiment of the present disclosure, the solvent includes a monohydric alcohol which is methanol, ethanol, propanol, or a combination thereof. A specific method of adding the monohydric alcohol will be described below when describing a method of producing the cigarette filter. The monohydric alcohol is a component that is more volatile than water, and a large amount of the monohydric alcohol may be lost after drying. However, in a case in which the lyocell tow is stored at room temperature without undergoing a drying process, a certain amount or higher of the monohydric alcohol may be detected in the final cigarette filter. The monohydric alcohol may not only replace water in the solvent of the binder solution and thus help improve the hardness of the cigarette filter, but also express additional functionality when applied to the lyocell tow due to having sterilizing power. According to one embodiment of the present disclosure, the monohydric alcohol is included at 1 part by weight to 500 parts by weight based on 10,000 parts by weight of the lyocell tow. Since the monohydric alcohol is more volatile than polyhydric alcohol or water, the content of the monohydric alcohol is highly variable. However, in a case in which the drying process is reduced and the lyocell tow is stored at room temperature according to one embodiment of the present disclosure, since a certain amount or higher of the monohydric alcohol may be detected as compared to when the monohydric alcohol is not added, a lower limit of the above content range is considered more meaningful than the upper limit.

[0041] The cigarette filter including the lyocell tow according to one embodiment of the present disclosure has excellent hardness due to the lyocell fibers being bonded by the binder. 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, or 89% 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.

[0042] 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. Also, with the cigarette filter according to one embodiment of the present disclosure, an excellent hardness value of 85% or higher may be implemented as described above even after the elapse of time sufficient for the binder to settle at room temperature without undergoing a drying process at high temperature. Thus, the processability in product manufacturing can be significantly improved.

[0043] 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, storing the lyocell tow to allow the lyocell fibers to be bonded to each other by the binder after spraying the binder solution on the lyocell tow, and wrapping the lyocell tow, in which the lyocell fibers are bonded by the binder, 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.

[0044] 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.

[0045] 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 or storage 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 or storage, the amount of the binder supplied to the lyocell tow through spraying remains almost unchanged even in the final cigarette filter. 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.

[0046] The solvent includes water as well as a polyhydric alcohol. In a case in which the entire solvent is constituted by a polyhydric alcohol, the viscosity may be too high, and it may not be easy to disperse the binder. Water may be included as much as a remaining amount of a ratio occupied by the solvent such as a polyhydric alcohol and is partially lost in the drying process. According to one embodiment of the present disclosure, the polyhydric alcohol is included at 5 parts by weight to 50 parts by weight based on 100 parts by weight of the binder solution. Specifically, the content of the polyhydric alcohol 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, 50 parts by weight or less, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, or 30 parts by weight or less and may be in a range of 5 parts by weight to 50 parts by weight, 7 parts by weight to 40 parts by weight, or 10 parts by weight to 30 parts by weight. When applied within the above range, the polyhydric alcohol may impart additional functionality to the cigarette filter while not degrading the basic function of the lyocell tow as a filter.

[0047] The solvent may further include a monohydric alcohol. The monohydric alcohol is a component that is more volatile than water, and a large amount of the monohydric alcohol may be lost after drying. However, in a case in which the lyocell tow is stored at room temperature without undergoing a drying process, a certain amount or higher of the monohydric alcohol may be detected in the final cigarette filter. The monohydric alcohol is a component that can replace water in the solvent of the binder solution and may control the content of water in the final cigarette filter. According to one embodiment of the present disclosure, the monohydric alcohol is methanol, ethanol, propanol, or a combination thereof. Specifically, the monohydric alcohol may be ethanol.

[0048] The monohydric alcohol may be included at a certain level or higher in order to replace water. According to one embodiment of the present disclosure, the monohydric alcohol is included at 5 parts by weight to 60 parts by weight based on 100 parts by weight of the binder solution. Specifically, the content of the monohydric alcohol 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, 60 parts by weight or less, 55 parts by weight or less, 50 parts by weight or less, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, or 30 parts by weight or less and may be in a range of 5 parts by weight to 60 parts by weight, 7 parts by weight to 45 parts by weight, or 10 parts by weight to 30 parts by weight. When applied within the above range, the monohydric alcohol may reduce the content of water in the cigarette filter to a numerical value that is significant in terms of effects.

[0049] 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 based on 100 parts by weight of the lyocell tow is sprayed on 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.

[0050] After spraying the binder solution on the lyocell tow, the lyocell tow is stored to allow the binder to settle and the lyocell fibers to be bonded to each other by the binder. Such a process is a process distinguished from drying for a long time at high temperature. With the binder solution, for example, storage for six hours at room temperature is sufficient to proceed to a subsequent task, and thus the processability in product manufacturing can be increased.

[0051] The lyocell tow, in which the lyocell fibers are bonded by the binder, 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] The outside of the smoking material portion 10 and the filter portion 20 may be wrapped with a wrapper 30a or 30b.

[0057] 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.

[0058] 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.

[0059] 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

[0060] Hereinafter, the configurations of the present disclosure and the advantageous effects according thereto will be described in more detail using examples and comparative examples. 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

[0061] 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 10 wt% polyester (a copolymer of phthalic acid and sebacic acid or ethylene glycol, weight-average molecular weight (Mw) = 3,000 to 6,000) to a 90 wt% solvent (a solvent in which 30 wt% propylene glycol, 10 wt% ethanol, and 50 wt% water are mixed) 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 the lyocell tow was stored for 6 hours at room temperature to produce a lyocell tow including a binder. The produced 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

[0062] 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, instead of 10 wt% polyester, in the binder solution.

Example 3

[0063] A cigarette filter was produced in the same manner as in Example 2, except that a 90 wt% solvent (a solvent in which 30 wt% propylene glycol, 30 wt% ethanol, and 30 wt% water are mixed) was used as the solvent of the binder solution, instead of a 90 wt% solvent (a solvent in which 30 wt% propylene glycol, 10 wt% ethanol, and 50 wt% water are mixed).

Comparative Example 1

[0064] A cigarette filter was produced without spraying the binder solution on the lyocell tow.

Comparative Example 2

[0065] A cigarette filter was produced in the same manner as in Example 1, except that 90 wt% water was used as the solvent of the binder solution, instead of a 90 wt% solvent (a solvent in which 30 wt% propylene glycol, 10 wt% ethanol, and 50 wt% water are mixed).

a. Comparative Example 3

[0066] A cigarette filter was produced in the same manner as in Example 2, except that 90 wt% water was used as the solvent of the binder solution, instead of a 90 wt% solvent (a solvent in which 30 wt% propylene glycol, 10 wt% ethanol, and 50 wt% water are mixed).

Experimental Example

Experimental Example 1: Evaluation of hardness of cigarette filters

[0067] A hardness was measured for the cigarette filters produced according to Examples 1 to 3 and Comparative Examples 1 to 3. Specifically, the hardness of the cigarette filters was measured using a filter hardness measuring instrument (Filtrona's DHT 200^™) and Equation 1 below.

[0068] 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 (%)
Example 1	92.1
Example 2	89.8
Example 3	93.3
Comparative Example 1	83.5
Comparative Example 2	82.8
Comparative Example 3	81.3

[0069] According to Table 1 above, in a case in which a binder solution including a polyhydric alcohol as a solvent for a binder is used, just by storing the lyocell tow for 6 hours at room temperature without drying the lyocell tow for a long time at a particularly high temperature, an excellent hardness of 85% or higher can be secured. In this way, not only the drying time is significantly reduced, but also a change in hardness due to drying is little, which allows hardness to be stably secured. Accordingly, processability and productivity in the production of a cigarette filter can be improved.

[0070] Also, in a case in which a monohydric alcohol is used along with a polyhydric alcohol, since the content of moisture can be significantly reduced, it is possible to prevent a phenomenon of Comparative Examples 2 and 3 in which functionality of the binder is not sufficiently expressed due to moisture at an initial stage of spraying the binder solution.

[0071] In addition, when the lyocell tow is applied to a roll processing process or the like afterwards, a polyhydric alcohol included in the binder solution may serve as a release agent and prevent the lyocell tow from being rolled around a roll. Also, a monohydric alcohol, which is more volatile than water, may remain in a suitable amount in the cigarette filter and perform sterilization. In this way, additional functionality can be expressed.

[0072] 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

[0073] 

10: smoking material portion

20: filter portion

30a: smoking material portion wrapper

30b: filter portion wrapper

40: tipping paper

100: smoking article

Claims

1. A cigarette filter comprising:

lyocell tow made of a plurality of lyocell fibers;

a binder configured to bond the lyocell fibers to each other; and

a solvent dispersed in an inner space of the cigarette filter including the lyocell tow, wherein the solvent includes a polyhydric alcohol.

2. The cigarette filter of claim 1, wherein the polyhydric alcohol is a diol having a C1-C4 alkylene group.

3. The cigarette filter of claim 1, wherein the polyhydric alcohol is included at 0.5 parts by weight to 25 parts by weight based on 100 parts by weight of the lyocell tow.

4. The cigarette filter of claim 1, wherein the binder is hydroxypropyl methylcellulose, hydroxypropyl cellulose, polyvinyl alcohol, ethylene vinyl acetate, polyvinyl acetate, polyvinylpyrrolidone, polyester, or a combination thereof.

5. The cigarette filter of claim 1, wherein the binder is included at 0.1 parts by weight to 5 parts by weight based on 100 parts by weight of the lyocell tow.

6. The cigarette filter of claim 1, wherein the solvent further includes a monohydric alcohol which is methanol, ethanol, propanol, or a combination thereof.

7. A method of producing the cigarette filter of claim 1, the method comprising:

(1) using a plurality of lyocell fibers to produce lyocell tow;

(2) mixing a binder and a solvent to prepare a binder solution;

(3) storing the lyocell tow to allow the lyocell fibers to be bonded to each other by the binder after spraying the binder solution on the lyocell tow; and

(4) wrapping the lyocell tow, in which the lyocell fibers are bonded by the binder, with wrapping paper to produce the cigarette filter,

wherein the solvent includes a polyhydric alcohol.

8. The method of claim 7, wherein the polyhydric alcohol is included at 5 parts by weight to 50 parts by weight based on 100 parts by weight of the binder solution.

9. The method of claim 7, wherein the solvent further includes a monohydric alcohol.

10. The method of claim 9, wherein the monohydric alcohol is methanol, ethanol, propanol, or a combination thereof.

11. The method of claim 9, wherein the monohydric alcohol is included at 5 parts by weight to 60 parts by weight based on 100 parts by weight of the binder solution.

12. The method of claim 7, wherein the binder solution is sprayed on the lyocell tow in an amount of 5 parts by weight to 30 parts by weight based on 100 parts by weight of the lyocell tow.

Drawing