Lyocell material, cigarette filter and method for manufacturing the same

Abstract

This application relates to a lyocell material for cigarette filters, a cigarette filter containing the lyocell material, and a manufacturing method thereof. The lyocell material and the cigarette filter containing the same are excellent in biodegradability, while replacing conventional cellulose acetate materials and filters, and provide excellent filter manufacturing processability and excellent cigarette properties (e.g., draw resistance).

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0190179, filed December 28, 2021, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a lyocell material, a cigarette filter containing the same, and methods for producing the same. [Background technology]

[0003] Cellulose acetate fiber has been the primary material used for cigarette filters. Cellulose acetate is known to be a biodegradable substance, but cigarette filters made of cellulose acetate retain their original shape for one to two years after being buried in the soil, and it takes a considerable amount of time for them to fully biodegrade. Considering the amount and toxicity of tobacco products that are left in the living environment, as well as those that are collected and buried as waste after smoking, it is necessary to further improve the biodegradability of cigarette filters.

[0004] Since cigarettes are a luxury item enjoyed by inhaling the smoke produced when they are burned, the more uniform the concentration of the smoking smoke, the better the quality of the cigarette can be evaluated. One of the items that can be evaluated in relation to the uniformity of smoking smoke concentration is the resistance to draw of the filter, which is known to increase in proportion to the increase in the filtering efficiency of the filter. In other words, cigarette filters with excellent resistance to draw can be said to provide not only excellent filtering performance against harmful substances but also excellent user satisfaction (quality).

[0005] Therefore, there is a need to develop a filter material that can replace the conventional cellulose acetate material while achieving filter properties such as suction resistance at a level equal to or better than that of the conventional technology. Summary of the Invention [Problem to be solved by the invention]

[0006] One object of the present application is to provide a lyocell material that can replace cellulose acetate commercially available for use in cigarette filters.

[0007] Another object of the present application is to provide a lyocell material for cigarette filters which is manufactured in an environmentally friendly manner and has excellent biodegradability when disposed of.

[0008] A further object of the present application is to provide a lyocell material for cigarette filters that satisfies or improves the properties (e.g., resistance to draw) of cigarette filter materials.

[0009] Yet another object of the present application is to provide a lyocell filter for cigarettes.

[0010] Yet another object of the present application is to provide an (ultra) slim type lyocell filter for cigarettes.

[0011] It is yet another object of the present application to provide a cigarette comprising a lyocell filter.

[0012] A further object of the present application is to improve the processability involved in the manufacture of the aforementioned lyocell material, filters and cigarettes.

[0013] The above and other objects of the present application can all be achieved by the present invention, which will be described in detail below. [Means for solving the problem]

[0014] In one embodiment, the present application relates to a method for producing a lyocell material that can be used to make cigarette filters.

[0015] Specifically, the method includes the steps of spinning a lyocell dope, solidifying the spun lyocell dope to obtain a lyocell multifilament, treating the lyocell multifilament with an oil agent, and crimping the oil-treated lyocell multifilament into a crimp machine so that steam and roller pressure are applied to the lyocell multifilament.

[0016] In the method, one or more of the steps may be performed under controlled conditions so that the single filament fineness of the filaments constituting the lyocell multifilament (e.g., oil-treated multifilament) falls within a predetermined range. For example, the single filament fineness of the filaments constituting the lyocell multifilament may be greater than 4.0 denier and less than or equal to 8.0 denier.

[0017] In the method of the present application, the crimping step is performed to satisfy the crimp draft ratio expressed by the following Equation 1:

[0018] [Formula 1] 1.01≦crimp draft ratio≦1.30

[0019] In Equation 1, the crimp draft ratio is calculated as V1 / V0, where V0 means the filament moving speed before the oil-treated multifilament is fed into the crimping device, and V1 means the passing speed of the filament gripped by the rollers in the crimping device.

[0020] The method for producing a lyocell material according to the present invention will be described in detail below.

[0021] (a) Lyocell dope spinning stage This step involves spinning a lyocell dope, that is, a lyocell spinning dope containing cellulose (or cellulose pulp) and N-methylmorpholine-N-oxide (NMMO).

[0022] Commercially available cellulose acetate filters have been identified as a major source of microplastic emissions. However, the amine oxide solvent used in the production of lyocell fibers is recyclable and biodegradable upon disposal, meaning that lyocell materials do not generate any pollutants during their production process. Furthermore, lyocell tow is biodegraded and even removed within a relatively short period of time, making lyocell a more environmentally friendly material than cellulose acetate.

[0023] In one example, the cellulose content in the spinning dope is 5 to 15 wt % based on the total weight of the dope (100 wt %). If the cellulose content is too low, it is difficult to achieve the properties of lyocell fiber, and if the cellulose content exceeds this range, it is difficult to dissolve in a solvent. In consideration of this, the cellulose content in the spinning dope is 6 wt % or more, 7 wt % or more, 8 wt % or more, 9 wt % or more, or 10 wt % or more, with the upper limit being, for example, 14 wt % or less, 13 wt % or less, 12 wt % or less, 11 wt % or less, 10 wt % or less, or 9 wt % or less.

[0024] In one example, the spinning dope includes an aqueous solution of N-methylmorpholine-N-oxide (NMMO), which may contain, for example, 80 to 95 parts by weight of N-methylmorpholine-N-oxide (NMMO) and 5 to 20 parts by weight of water, taking into consideration the degree of dissolution of cellulose and the process temperature.

[0025] In one example, the cellulose or cellulose pulp has an α-cellulose content of 85 to 97% by weight relative to 100% by weight of the total cellulose.

[0026] In a specific example of the present application, the degree of polymerization (DPw) of the cellulose is also 600 to 1,700.

[0027] In the spinning step, the shape of the spinneret for discharging the spinning dope is not particularly limited. For example, a doughnut-shaped spinneret may be used.

[0028] The nozzle temperature of the spinneret, specifically the spinning temperature, can be appropriately selected by those skilled in the art. Taking into consideration that the viscosity of the spinning dope varies depending on the spinning temperature, and therefore the extrusion may not be performed well, the spinning temperature may be, for example, 100°C to 120°C, or 100°C to 110°C.

[0029] In one example, the spinning dope may be spun under controlled spinning conditions so that the fineness of the monofilaments and / or multifilaments falls within a predetermined range. For example, the spinning dope may be spun under controlled spinning conditions so that the single filament fineness is greater than 4.0 denier and less than 8.0 denier. For example, by appropriately controlling one or more of the spinning dope throughput and the spinning speed, the single filament fineness of the filament forming the lyocell material may be greater than 4.0 denier and less than 8.0 denier. In this case, the single filament fineness refers to the fineness of a single monofilament separated from a multifilament. In some cases, the total fineness may be controlled within a predetermined range by adjusting the number of filaments.

[0030] Specifically, the filament single-filament fineness is, for example, 7.5 denier or less, 7.0 denier or less, 6.5 denier or less, 6.0 denier or less, 5.5 denier or less, 5.0 denier or less, or 4.5 denier or less. The lower limit is, for example, 4.5 denier or more, 5.0 denier or more, 5.5 denier or more, or 6.0 denier or more. Satisfying the above ranges is advantageous for achieving stable draw resistance of the cigarette filter and ensuring processability. In particular, as will be seen in the comparative examples described below, if the filament single-filament fineness exceeds the above ranges, the draw resistance of the cigarette filter may be significantly reduced.

[0031] The spinning dope discharged through the spinneret undergoes a coagulation stage, which will be described later.

[0032] (b) Coagulation step and obtaining multifilaments In this step, the spun lyocell spinning dope is solidified to obtain lyocell multifilaments.

[0033] The coagulation may be carried out by contacting the spinning dope with air and / or a coagulation liquid.

[0034] In one example, the coagulation step includes a primary coagulation step in which cooling air is supplied to the spun lyocell dope, and a secondary coagulation step in which the primarily coagulated spinning dope is introduced into a coagulation liquid to coagulate it.

[0035] By the solidification method described above, the lyocell dope discharged from the spinneret can be primarily solidified in the space (air gap section) between the spinneret and the solidification bath. For example, cooling air can be supplied to such an air gap section from the inside to the outside of the spinneret from an air cooling section located inside the spinneret. Alternatively, primary solidification can be performed by a so-called air quenching method or means known in the related field.

[0036] In one example, the upper limit of the temperature of the cooling air used for the primary solidification is, for example, 15° C. or less. Specifically, the cooling air may have a temperature of 14° C. or less, 13° C. or less, 12° C. or less, 11° C. or less, or 10° C. or less. If the temperature exceeds the above range, the spinning dope may not be sufficiently solidified by the air, resulting in poor spinning processability.

[0037] The lower limit of the cooling air temperature can be determined in consideration of the spinning process and / or the cross-sectional uniformity of the filaments. For example, if the temperature of the cooling air is less than 4°C, the surface of the spinneret becomes cold, the surface of the filaments becomes uneven, and the spinning process also deteriorates. Taking this into consideration, the cooling air temperature can be 5°C or more, 6°C or more, 7°C or more, 8°C or more, or 9°C or more.

[0038] The amount of cooling air supplied can be adjusted in consideration of sufficient solidification, spinning processability, and effects on the physical properties of the filaments. For example, the amount of cooling air supplied to the spinning dope is adjusted to 70 to 300 Nm. 3 More specifically, the air volume is 100 Nm 3 / h or more or 150Nm 3 / h or more, and the upper limit of the air volume is, for example, 250Nm 3 / h or less or 200Nm 3 / h or less.

[0039] After the primary coagulation as described above, the cooled spinning dope may be supplied to a coagulation tank or bath containing a coagulation liquid (secondary coagulation). For proper coagulation to proceed, the temperature of the coagulation liquid may be, for example, 30°C or less or 25°C or less. The temperature of the coagulation liquid may be 10°C or more, 15°C or more, or 20°C or more. When the above temperatures are maintained, the coagulation rate may be maintained appropriately.

[0040] The type of coagulation liquid for the secondary coagulation is not particularly limited, and may include, for example, one or more of water and N-methylmorpholine-N-oxide (NMMO).

[0041] Although not particularly limited, when the coagulation liquid contains water and N-methylmorpholine-N-oxide (NMMO), the water content in the coagulation liquid is 60 to 90 wt % and the N-methylmorpholine-N-oxide (NMMO) content is 10 to 40 wt %. Alternatively, the coagulation liquid may contain 70 to 80 wt % water and 20 to 30 wt % N-methylmorpholine-N-oxide (NMMO). The concentrations of the coagulation liquid can be controlled to be maintained during the manufacturing process using a sensor or the like.

[0042] (c) Water washing stage If necessary, after the coagulation step and the step of obtaining the multifilament, the multifilament may be washed with water to remove N-methylmorpholine-N-oxide (NMMO) and / or other impurities remaining in the filament.

[0043] The method of washing with water is not particularly limited. For example, washing with water can be performed by using a pulling roller to introduce the solidified lyocell multifilament into a washing tank. Alternatively, washing with water can be performed by spraying a washing liquid during the process of moving to the next stage by the pulling roller.

[0044] The components of the washing liquid are not particularly limited. For example, the washing liquid may contain water and may further contain known additives.

[0045] In addition, in consideration of reuse after washing, the washing liquid may be adjusted to a temperature of 100° C. or less.

[0046] (d) Oil treatment stage This step applies an oil to the surface of the filament to reduce friction applied to the filament and to allow a good crimp to be formed in the crimping step described below.

[0047] Although not particularly limited, the oil treatment may be performed by immersing the multifilament in a bath filled with oil so that the multifilament is completely immersed in the oil, or by spraying an oil solution during the process of moving the multifilament to the next stage by a pulling roller.

[0048] After the oil treatment as described above, a process of squeezing out the oil from the surface of the multifilament using a roll or the like may be added before and / or after the oil treatment step so that the amount of oil applied to the multifilament is constant.

[0049] In one example, the oil treatment may be performed so that the content of the oil is about 5% by weight or less, based on 100% by weight of the oil-treated multifilament. Specifically, the amount of oil in the oil-treated multifilament may be 4% by weight or less, 3% by weight or less, or 2% by weight or less, and may be 0.5% by weight or more, 1% by weight or more, or 2% by weight or more.

[0050] The type of oil that can be used is not particularly limited, and any oil known in the related technical field can be used.

[0051] Optionally, after the oil treatment as described above, the oil may be dried.

[0052] In an embodiment of the present application, one or more of the above steps may be performed under controlled conditions so that the monofilament and / or multifilament has a predetermined fineness. For example, the above steps may be controlled so that the single filament fineness of the lyocell multifilament is greater than 4.0 denier and less than 8.0 denier. In this case, the single filament fineness refers to the fineness of a single monofilament separated from the multifilament.

[0053] Specifically, the filament single-filament fineness is, for example, 7.5 denier or less, 7.0 denier or less, 6.5 denier or less, 6.0 denier or less, 5.5 denier or less, 5.0 denier or less, or 4.5 denier or less. The lower limit is, for example, 4.5 denier or more, 5.0 denier or more, 5.5 denier or more, or 6.0 denier or more. Satisfying the above ranges is advantageous for achieving stable draw resistance of the cigarette filter and ensuring processability. In particular, as will be seen in the comparative examples described below, if the filament single-filament fineness exceeds the above ranges, the draw resistance of the cigarette filter may be significantly reduced.

[0054] Although not particularly limited, the step of controlling the filament to have a predetermined fineness range can be the spinning step, or the spinning, coagulation, water washing, and oil treatment steps can all be controlled to ensure the single filament fineness range.

[0055] (e) Crimping step The crimping step is a step in which pressure is applied to the oil-treated lyocell multifilament using steam and a roller to obtain a crimped tow, and may be referred to as a crimping step.

[0056] Through crimping, waves are imparted to the multifilament, and the fibers can have bulky properties. Crimping can be performed using a known crimping device, including a stuffer box and / or a steam box. The crimping device that can be used is not particularly limited, as long as it is capable of applying steam pressure and roll pressure, as described below.

[0057] In one example, the crimping step may be performed by first supplying steam to the lyocell multifilament to preheat and swell the multifilament, and then pressing the multifilament with a press roller to form wrinkles in the multifilament. In this case, a steam box is used to supply steam, and the steam box may be located at the front end of the crimping device.

[0058] In one example, the crimping step may be performed by simultaneously pressing the multifilaments with a press roller and applying steam.

[0059] In one example, the crimping step may be performed by first supplying steam to the lyocell multifilament to preheat and swell the multifilament, and then simultaneously pressing the multifilament with a press roller and applying steam.

[0060] In one example, the crimping step is performed by applying a pressure of 0.1 to 2.0 kgf / cm to the multifilament before feeding it into a crimping device (specifically, a press roller). 2 In the specific example of the present application, the steam is added at 0.2 kgf / cm 2 More than 0.3kgf / cm 2 Over 0.4kgf / cm 2 More than 0.5kgf / cm 2 or more than 0.6kgf / cm 2 More than 1.5 kgf / cm can be provided by the steam box. 2 Below, 1.4kgf / cm 2 Below, 1.3kgf / cm 2 Below, 1.2kgf / cm 2 Below, 1.1kgf / cm 2 or less than 1.0kgf / cm 2The following steam may be provided: If the steam supply amount or pressure is below the above range, the crimp will not be formed smoothly; if it exceeds the above range, the filament will be too flexible, and the filament will be excessively crimped in the crimping device, making it impossible to pass through the crimping device.

[0061] In one example, the crimping step uses a roller to apply a pressure of 1.5 to 4.0 kgf / cm to the multifilament fed into the crimping device. 2 In the specific example of the present application, the pressure is 1.6 kgf / cm. 2 More than 1.7kgf / cm 2 Above, 1.8kgf / cm 2 Over 1.9kgf / cm 2 Over 2.0kgf / cm 2 Above, 2.1kgf / cm 2 Above, 2.2kgf / cm 2 Above, 2.3kgf / cm 2 Over 2.4kgf / cm 2 A pressure of 2.5 kgf / cm or more can be applied to the multifilament through a press roller. 2 Below, 3.8kgf / cm 2 Below, 3.7kgf / cm 2 Below, 3.6kgf / cm 2 Below, 3.5kgf / cm 2 Below, 3.4kgf / cm 2 Below, 3.3kgf / cm 2 Below, 3.2kgf / cm 2 Below, 3.1kgf / cm 2 Below, 3.0kgf / cm 2 Below, 2.9kgf / cm 2 Below, 2.8kgf / cm 2 Below, 2.7kgf / cm 2 Below, 2.6kgf / cm 2 or less than 2.5kgf / cm 2The following pressures can be applied. If the roller pressure is below this range, the desired number of crimps will not be formed sufficiently. If the roller pressure exceeds this range, the pressing force will be too strong, and the filament will not be able to be smoothly fed into the crimping device or pass through the stuffer box. The press rollers that apply this pressure may cause wrinkles to form in the multifilament.

[0062] In one example, a doctor blade that applies a predetermined pressure to the multifilament may be used in the crimping step. The doctor blade adjusts the residence time of the filaments introduced into the crimper box and contributes to the number of crimps (which affects the quality of the tow and filter performance). For example, such a doctor blade may be located in the path of the multifilament that is discharged at the roller pressure point after being pressed by the roller.

[0063] In a specific example of the present application, the crimping step uses a doctor blade to apply a pressure of 0.1 to 2.0 kgf / cm to the multifilament that has passed through the rollers of the crimping device. 2 More specifically, the pressure applied by the doctor blade is 0.2 kgf / cm. 2 More than 0.3kgf / cm 2 Over 0.4kgf / cm 2 or more than 0.5kgf / cm 2 The upper limit of the pressure is, for example, 1.5 kgf / cm. 2 Below, 1.4kgf / cm 2 Below, 1.3kgf / cm 2 Below, 1.2kgf / cm 2 Below, 1.1kgf / cm 2 or less than 1.0kgf / cm 2 Also the following:

[0064] In one example, the crimping step may be performed at a temperature in the range of 120 to 250°C. If the temperature is too low, the shape stability of the crimp may be poor, and if the temperature is too high, the concentration of retained materials in the stuffer box may increase, making crimping difficult. Therefore, taking into consideration the steam pressure, the temperature may be appropriately controlled within the range of 130°C or higher, 140°C or higher, or 150°C or higher, and 200°C or lower, 180°C or lower, or 160°C or lower.

[0065] As described above, the crimping step is performed to satisfy the crimp draft ratio expressed by the following Equation 1. At this time, the pressure applied to the filament fed into the crimping device is also provided by the rollers.

[0066] [Formula 1] 1.01≦crimp draft ratio≦1.30

[0067] In Equation 1, the crimp draft ratio is calculated as V1 / V0, where V0 means the filament moving speed before the oil-treated multifilament is fed into the crimping device, and V1 means the passing speed of the filament gripped by the rollers in the crimping device. Here, the passing speed may mean the speed at which the multifilament is fed into the crimping step (or fed into the crimping device) and moves between the steam step and / or the press roller step.

[0068] A method performed under conditions that satisfy Equation 1 can impart uniform crimps to the tow. For example, as confirmed in the experiments described below, the upper and lower limits of the range of the number of crimps in the tow calculated by arithmetic average are closer to each other than in the comparative examples for the tows manufactured under conditions that satisfy Equation 1 (i.e., ensuring uniformity of the tow). Furthermore, when the tow of the present application, in which the crimps are uniformly formed, is manufactured into a cigarette filter, the arrangement of the fibers or fiber strands is uniform. This can provide a high level of resistance to draw, as described below.

[0069] Furthermore, as confirmed in the experiments described below, a method performed under the condition of satisfying Equation 1 can impart a good crimp to the tow. A good crimp tow functions advantageously to improve the resistance to suction.

[0070] Furthermore, if the range of Equation 1 is not satisfied, the tow production conditions are inappropriate, and either the tow cannot be produced, or even if the tow can be produced, the crimp shape produced is poor and the tow is non-uniform, resulting in poor cigarette filter production processability, and as a result, it is difficult to provide a filter with excellent draw resistance.

[0071] (f) Other stages After crimping, any appropriate post-processing can be performed.

[0072] In one example, a secondary oil treatment (g) may be additionally performed. This secondary oil treatment may prevent static electricity from being generated in the tow and may impart flexibility to the tow. This secondary oil treatment may be the same as or similar to the oil treatment step (d) described above.

[0073] In one example, a drying step (h) may be additionally performed. The drying may be performed at a temperature ranging from 100 to 130°C, for example. The drying method or mode is not particularly limited, and known techniques may be used. For example, the drying may be performed by applying hot air to the tow, passing the tow through a temperature-controlled room for a certain period of time, or leaving the tow in the room.

[0074] According to a specific example of the present application, a tow having 20 to 50 crimps per inch formed therein can be provided by a method including the crimping step described above. For example, the number of crimps can be 25 ea / inch or more, 30 ea / inch or more, 35 ea / inch or more, 40 ea / inch or more, or 45 ea / inch or more, with the upper limit being, for example, 45 ea / inch or less, 40 ea / inch or less, 35 ea / inch or less, 30 ea / inch or less, or 25 ea / inch or less. The number of crimps and their uniformity can be adjusted through the crimping step described above, for example, the crimp draft ratio. The crimped tow produced by the method of the present application not only has the number of crimps described above, but also has the crimps formed uniformly, so that when it is manufactured into a cigarette filter, it can provide a high level of resistance to draw, as described below.

[0075] According to the present application, a lyocell material (tow) having a fineness appropriate for the manufacture of cigarette filters and ensuring their functionality can be provided. The total fineness of the tow is a factor related to the amount of filaments that can be inserted into the filter paper. If the total fineness is too low, a sufficient amount of filaments cannot be loaded into the filter paper, resulting in poor draw resistance. If the total fineness is too high, the amount loaded into the filter paper will be too high, causing the filter paper to tear or making it difficult to adjust the tow loading amount to achieve the required draw resistance. In this regard, according to an embodiment of the present application, a crimped tow having a total fineness of 15,000 to 35,000 denier can be provided. For example, the lower limit of the total fineness can be, for example, 16,000 or more, 17,000 or more, 18,000 or more, 19,000 or more, or 20,000 or more, and the upper limit can be, for example, 30,000 or less or 25,000 or less.

[0076] If the tow fineness is outside the above range, as in the comparative examples described below, the processability of producing cigarette filters will be poor (continuous processing will be impossible due to thread breakage), and the amount of tow packed into the filter paper during cigarette filter production will be too small or too large, making it difficult to ensure sufficient filter properties (e.g., draw resistance). Alternatively, if the total tow fineness is outside the above range, the amount packed into the filter paper will be too large, causing the filter paper to tear, or making it difficult to adjust the tow filling amount to achieve the draw resistance required for the filter.

[0077] In a specific example of the present application, the fineness of the lyocell multifilament can be controlled to an appropriate value depending on the circumferential size of the filter.

[0078] For example, when the lyocell material is used in an (ultra) slim filter (eg, the circumference of the filter rod is 19 mm or less), the total fineness of the lyocell multifilaments may be in the range of 15,000 to 25,000 denier. Specifically, the total fineness of the lyocell multifilaments used in the ultra-slim filter is 16,000 denier or more, 17,000 denier or more, 18,000 denier or more, 19,000 denier or more, 20,000 denier or more, 21,000 denier or more, 22,000 denier or more, 23,000 denier or more, or 24,000 denier or more, and 24,000 denier or less, 23,000 denier or less, 22,000 denier or less, 21,000 denier or less, 20,000 denier or less, 19,000 denier or less, 18,000 denier or less, 17,000 denier or less, or 16,000 denier or less. In such a case, the single yarn fineness of the lyocell monofilament is 4.5 denier or more, for example, 5.0 denier or more, 5.5 denier or more, 6.0 denier or more, 6.5 denier or more, 7.0 denier or more, or even 7.5 denier or more.

[0079] As described above, the present application can provide a lyocell material having a total fineness within the above range, specifically, a fineness that can ensure filter performance suitable for (ultra) slim filters.

[0080] The total fineness of the tow can be determined by the single filament fineness and the number of crimps, but in the method of the present application, as described above, the single filament fineness and the number of crimps are controlled, and therefore the total fineness of the tow described above that is suitable for filter production and ensuring its functionality can be ensured.

[0081] In another embodiment of the present application, the present application relates to a lyocell material, which is manufactured through a process that satisfies at least the above-mentioned mathematical formula 1.

[0082] Specifically, the lyocell material may be a crimped tow that is produced by being fed into a crimping device so that a crimp can be imparted under the condition that the crimp draft ratio expressed by the following mathematical formula 1 is satisfied, or may include the same.

[0083] [Formula 1] 1.01≦crimp draft ratio≦1.30

[0084] In the above formula 1, the crimp draft ratio is calculated as V1 / V0, where V0 means the filament moving speed before the multifilament is fed into the crimping device, and V1 means the passing speed of the filament gripped by the rollers in the crimping device.

[0085] In a specific example of the present application, the tow may have 20 to 50 crimps per inch and a total fineness of 15,000 to 35,000 denier. Specific values ​​are as described above.

[0086] In one example, the tow, i.e., the crimped lyocell multifilament, has a total fineness of 15,000 to 35,000 denier. More specifically, the total fineness of the multifilament is 15,000 to 25,000 denier. Specific values ​​are as described above.

[0087] In one example, the single filament fineness of the monofilament constituting the lyocell multifilament is more than 4.0 denier and not more than 8.0 denier, the specific values ​​of which are as described above.

[0088] As described above, in the specific example of the present application, the fineness of the lyocell multifilament can be controlled to an appropriate value depending on the circumferential size of the filter.

[0089] For example, when the lyocell material is used in an (ultra) slim filter (e.g., the circumference of the filter rod is 19 mm or less), the total fineness of the lyocell multifilaments may be in the range of 15,000 to 25,000 denier. Specifically, the total fineness of the lyocell multifilaments used in the ultra-slim filter is 16,000 denier or more, 17,000 denier or more, 18,000 denier or more, 19,000 denier or more, 20,000 denier or more, 21,000 denier or more, 22,000 denier or more, 23,000 denier or more, or 24,000 denier or more, and 24,000 denier or less, 23,000 denier or less, 22,000 denier or less, 21,000 denier or less, 20,000 denier or less, 19,000 denier or less, 18,000 denier or less, 17,000 denier or less, or 16,000 denier or less. In such a case, the single yarn fineness of the lyocell monofilament is 4.5 denier or more, for example, 5.0 denier or more, 5.5 denier or more, 6.0 denier or more, 6.5 denier or more, 7.0 denier or more, or even 7.5 denier or more.

[0090] In one example, the lyocell material can be produced by the above-mentioned method for producing a lyocell material, specifically, by going through the above-mentioned steps of spinning, coagulation, washing, oil treatment, and crimping.

[0091] The rest of the explanation about the lyocell material is the same as that about the manufacturing method of the lyocell material, so it will be omitted.

[0092] In yet another embodiment of the present invention, the present invention relates to a method for producing a cigarette filter, which method includes any of the methods for producing a lyocell material described above.

[0093] Specifically, the method includes the steps of spinning a lyocell dope, solidifying the spun lyocell dope to obtain a lyocell multifilament, treating the lyocell multifilament with an oil agent, crimping the oil-treated lyocell multifilament into a crimping device so that steam and roller pressure are applied to the lyocell multifilament, and manufacturing a filter using the crimped tow.

[0094] In addition, in connection with the method for manufacturing the cigarette filter (specifically, the process for manufacturing the lyocell material), one or more of the steps may be performed under controlled conditions so that the fineness of the lyocell multifilament (e.g., oil-treated lyocell multifilament) satisfies a predetermined range. For example, one or more of the steps included in the method of the present application may be performed under controlled conditions so that the single yarn fineness of the monofilament constituting the multifilament is more than 4.0 denier and not more than 8.0 denier.

[0095] In each step of the manufacturing method of the cigarette filter, the steps that overlap with those described in the above-mentioned Lyocell material are omitted because the contents are the same.

[0096] In addition, in a specific example of the present application, the crimping step may be performed to satisfy a crimp draft ratio expressed by the following Equation 1.

[0097] [Formula 1] 1.01≦crimp draft ratio≦1.30

[0098] In the above formula 1, the crimp draft ratio is calculated as V1 / V0, where V0 means the filament moving speed before the oil-treated multifilament is fed into the crimping device, and V1 means the passing speed of the filament gripped by the rollers in the crimping device.

[0099] In one example, the tow may have 20 to 50 crimps per inch. The specific description is the same as that described above, so it will be omitted.

[0100] The steps of manufacturing a filter performed after the crimping step can be appropriately performed by those skilled in the art using known methods. For example, a filter can be manufactured by forming a rod-shaped wrapper paper (also called a wrapper paper, filter, or filter wrapper paper) filled with tow. Alternatively, a filter can be manufactured by cutting the rod-shaped tow-filled filter paper to an appropriate length.

[0101] The wrapper paper is a porous or non-porous paper that can cover and wrap the lyocell tow (i.e., tow that has been at least oil-treated and crimped) and maintain the filter shape (e.g., columnar or cylindrical).

[0102] In one example, when a porous wrapper paper is used, the wrapper paper may have a porosity of 10 to 50,000 CU (coresta units). Specifically, the lower limit of the porosity of the wrapper paper is, for example, 1,000 CU or more, 5,000 CU or more, 10,000 CU or more, 15,000 CU or more, 20,000 CU or more, 25,000 CU or more, 30,000 CU or more, 35,000 CU or more, 40,000 CU or more, or 45,000 CU or more, and the upper limit is, for example, 45,000 CU or less, 40,000 CU or less, 35,000 CU or less, 30,000 CU or less, 25,000 CU or less, 20,000 CU or less, 15,000 CU or less, 10,000 CU or less, or 5,000 CU or less.

[0103] In an embodiment of the present application, the cigarette filter may have a predetermined shape and size.

[0104] For example, the filter may have a rod shape. More specifically, the cigarette filter may have a cylindrical shape.

[0105] The filter may have a length of, for example, 10 to 150 mm. Specifically, the filter length may have a lower limit of 20 mm or more, 30 mm or more, 40 mm or more, 50 mm or more, 60 mm or more, 70 mm or more, 80 mm or more, 90 mm or more, 100 mm or more, 110 mm or more, 120 mm or more, 130 mm or more, 140 mm or more, or 150 mm or more. The filter length may have an upper limit of 150 mm or less, 140 mm or less, 130 mm or less, 120 mm or less, 110 mm or less, 100 mm or less, 90 mm or less, 80 mm or less, 70 mm or less, 60 mm or less, 50 mm or less, 40 mm or less, 30 mm or less, or 20 mm or less.

[0106] In a specific example of the present application, the filter having the length has a circular cross section, and the circumference of the circular cross section is in the range of 10 mm to 30 mm. For example, the circumference of the filter may have a lower limit of 15 mm or more, 20 mm or more, or 25 mm or more, and an upper limit of 25 mm or less, 20 mm or less, or 15 mm or less.

[0107] Although not particularly limited, the tow may be subjected to an opening treatment or a plasticizer treatment before being packed into the filter paper.

[0108] In one example, the cigarette filter manufactured by the method may satisfy a resistance to draw of 375 mmH2O or more as measured according to KS H ISO 6565. Specifically, the resistance to draw of the cigarette filter may be 380 mmH2O or more, 390 mmH2O or more, 400 mmH2O or more, 410 mmH2O or more, 420 mmH2O or more, 430 mmH2O or more, 440 mmH2O or more, 450 mmH2O or more, 460 mmH2O or more, or 470 mmH2O or more. The upper limit of the resistance to draw may be, for example, 810 mmH2O or less. Specifically, the upper limit of the suction resistance is, for example, 800 mmH2O or less, 750 mmH2O or less, 700 mmH2O or less, 650 mmH2O or less, 600 mmH2O or less, 550 mmH2O or less, 500 mmH2O or less, 450 mmH2O or less, or 400 mmH2O or less.

[0109] Although not particularly limited, the resistance to draw may be measured for a filter rod having a circumference of 10 mm to 30 mm, or 15 mm to 27 mm. The circumference of a cigarette filter is determined by the number of crimps in the tow, the quality of the tow (e.g., uniformity of the crimp shape), etc., and the resistance to draw may be determined by the fineness, cross-sectional shape, etc.

[0110] Although not particularly limited, the resistance to draw is measured for a filter rod containing a wrapper paper having a porosity of 5,000 to 15,000 CU and having a length in the range of 60 mm to 150 mm.

[0111] Although not particularly limited, the resistance to draw may be measured for rod-shaped filters weighing between 300 mg and 1,000 mg, 400 mg and 900 mg, 500 mg and 800 mg, or 600 mg and 700 mg.

[0112] As mentioned above, the present application can provide a lyocell material having a fineness within the above-mentioned range, specifically a fineness that can ensure filter performance suitable for (ultra) slim filters. Furthermore, a cigarette filter containing such a lyocell material can have a predetermined resistance to draw.

[0113] For example, when the lyocell material is used in an (ultra) slim filter (e.g., when the circumference of the filter rod is 19 mm or less, specifically, the upper limit of the circumference is, for example, 18.5 mm or less, 18 mm or less, 17.5 mm or less, 17 mm or less, or 16.5 mm or less, and the lower limit is, for example, 15.0 mm or more, 15.5 mm or more, 16.5 mm or more, 17.0 mm or more, 17.5 mm or more, 18.0 mm or more, or 18.5 mm or more), the total fineness of the lyocell multifilaments is in the range of 15,000 to 25,000 denier. Specifically, the total fineness of the lyocell multifilaments used in the ultra-slim filter is 16,000 denier or more, 17,000 denier or more, 18,000 denier or more, 19,000 denier or more, 20,000 denier or more, 21,000 denier or more, 22,000 denier or more, 23,000 denier or more, or 24,000 denier or more, and 24,000 denier or less, 23,000 denier or less, 22,000 denier or less, 21,000 denier or less, 20,000 denier or less, 19,000 denier or less, 18,000 denier or less, 17,000 denier or less, or 16,000 denier or less. In such cases, the lyocell monofilament has a single yarn fineness of 4.5 denier or more, e.g., 5.0 denier or more, 5.5 denier or more, 6.0 denier or more, 6.5 denier or more, 7.0 denier or more, or 7.5 denier or more. Cigarette filters containing lyocell material of such fineness also have a resistance to draw of 375 mmH2O or more as measured by KS H ISO 6565. Specifically, the cigarette filter may have a resistance to draw of 380 mmH2O or more, 390 mmH2O or more, 400 mmH2O or more, 410 mmH2O or more, 420 mmH2O or more, 430 mmH2O or more, 440 mmH2O or more, 450 mmH2O or more, 460 mmH2O or more, 470 mmH2O or more, 480 mmH2O or more, 490 mmH2O or more, 500 mmH2O or more, 510 mmH2O or more, 520 mmH2O or more, 530 mmH2O or more, 540 mmH2O or more, 550 mmH2O or more, 560 mmH2O or more, 570 mmH2O or more, 580 mmH2O or more, 590 mmH2O or more, or 600 mmH2O or more.In this case, the upper limit of the suction resistance is, for example, 810 mmH2O or less, specifically, 800 mmH2O or less, 750 mmH2O or less, 700 mmH2O or less, or 650 mmH2O or less.

[0114] A filter having the above resistance to draw values ​​can provide uniformity in smoke concentration and excellent filter performance when a user smokes a cigarette.

[0115] In yet another embodiment of the present application, the present application relates to a cigarette filter, the cigarette filter including a lyocell material, the lyocell material being the same as that described above.

[0116] Specifically, the lyocell material is also a crimped tow that is produced by being fed into a crimping device so that the crimp can be given under the condition that satisfies the crimp draft ratio expressed by the following Equation 1.

[0117] [Formula 1] 1.01≦crimp draft ratio≦1.30

[0118] In the above formula 1, the crimp draft ratio is calculated as V1 / V0, where V0 means the filament moving speed before the multifilament is fed into the crimping device, and V1 means the passing speed of the filament gripped by the rollers in the crimping device.

[0119] In a specific example of the present application, the tow has 20 to 50 crimps per inch and a total fineness of 15,000 to 35,000 denier. Specific values ​​are as described above.

[0120] In one example, the lyocell material contained in the cigarette filter is produced by the above-mentioned method for producing a lyocell material, specifically, by undergoing the above-mentioned steps of spinning, coagulation, washing, oil treatment, and crimping.

[0121] In one example, the cigarette filter further includes a wrapper, i.e., the cigarette filter includes a lyocell material and a wrapper that encases the lyocell material. The description of the wrapper has been given above, so it will be omitted here.

[0122] The description of the filter shape has been given above, so it will be omitted here.

[0123] In one example, the cigarette filter may satisfy a resistance to draw of 375 mmH2O or more as measured according to KS H ISO 6565. Specifically, the resistance to draw of the cigarette filter may be 380 mmH2O or more, 390 mmH2O or more, 400 mmH2O or more, 410 mmH2O or more, 420 mmH2O or more, 430 mmH2O or more, 440 mmH2O or more, 450 mmH2O or more, 460 mmH2O or more, or 470 mmH2O or more. The upper limit of the resistance to draw may be, for example, 810 mmH2O or less. More specifically, the upper limit of the suction resistance is 800 mmH2O or less, 750 mmH2O or less, 700 mmH2O or less, 650 mmH2O or less, 600 mmH2O or less, 550 mmH2O or less, 500 mmH2O or less, 450 mmH2O, or 400 mmH2O or less.

[0124] Although not particularly limited, the resistance to draw may be measured for a filter rod having a circumference of 10 mm to 30 mm, or 15 mm to 27 mm. The circumference of a cigarette filter is determined by the number of crimps in the tow, the quality of the tow (e.g., the uniformity of the crimp shape), etc., and the resistance to draw may be determined by the fineness, cross-sectional shape, etc.

[0125] Although not particularly limited, the resistance to draw is measured for a filter rod containing a wrapper paper having a porosity of 5,000 to 15,000 CU and having a length in the range of 60 mm to 150 mm.

[0126] Although not particularly limited, the resistance to draw may be measured for a rod-shaped filter having a weight of 300 mg to 1000 mg, 400 mg to 900 mg, 500 mg to 800 mg, or 600 mg to 700 mg.

[0127] As mentioned above, the present application can provide a lyocell material having a fineness within the above-mentioned range, specifically a fineness that can ensure filter performance suitable for (ultra) slim filters. Furthermore, a cigarette filter containing such a lyocell material can have a predetermined resistance to draw.

[0128] For example, when the lyocell material is used in an (ultra) slim filter (e.g., when the circumference of the filter rod is 19 mm or less, specifically, the upper limit of the circumference is, for example, 18.5 mm or less, 18 mm or less, 17.5 mm or less, 17 mm or less, or 16.5 mm or less, and the lower limit is, for example, 15.0 mm or more, 15.5 mm or more, 16.5 mm or more, 17.0 mm or more, 17.5 mm or more, 18.0 mm or more, or 18.5 mm or more), the total fineness of the lyocell multifilaments is in the range of 15,000 to 25,000 denier. Specifically, the total fineness of the lyocell multifilaments used in the ultra slim filter is 16,000 denier or more, 17,000 denier or more, 18,000 denier or more, 19,000 denier or more, 20,000 denier or more, 21,000 denier or more, 22,000 denier or more, 23,000 denier or more, or 24,000 denier or more, and 24,000 denier or less, 23,000 denier or less, 22,000 denier or less, 21,000 denier or less, 20,000 denier or less, 19,000 denier or less, 18,000 denier or less, 17,000 denier or less, or 16,000 denier or less. In such cases, the lyocell monofilament has a single yarn fineness of 4.5 denier or more, e.g., 5.0 denier or more, 5.5 denier or more, 6.0 denier or more, 6.5 denier or more, 7.0 denier or more, or 7.5 denier or more. Cigarette filters containing lyocell material of such fineness also have a resistance to draw of 375 mmH2O or more as measured by KS H ISO 6565. Specifically, the cigarette filter may have a resistance to draw of 380 mmH2O or more, 390 mmH2O or more, 400 mmH2O or more, 410 mmH2O or more, 420 mmH2O or more, 430 mmH2O or more, 440 mmH2O or more, 450 mmH2O or more, 460 mmH2O or more, 470 mmH2O or more, 480 mmH2O or more, 490 mmH2O or more, 500 mmH2O or more, 510 mmH2O or more, 520 mmH2O or more, 530 mmH2O or more, 540 mmH2O or more, 550 mmH2O or more, 560 mmH2O or more, 570 mmH2O or more, 580 mmH2O or more, 590 mmH2O or more, or 600 mmH2O or more.In this case, the upper limit of the suction resistance is, for example, 810 mmH2O or less, specifically, 800 mmH2O or less, 750 mmH2O or less, 700 mmH2O or less, or 650 mmH2O or less.

[0129] A filter having the above resistance to draw values ​​can provide uniformity in smoke concentration and excellent filter performance when a user smokes a cigarette. [Effects of the Invention]

[0130] This application provides a lyocell material for cigarette filters that can replace the widely used cellulose acetate (CA), and a cigarette filter containing the same. Specifically, this application has the effect of providing not only excellent biodegradability, but also excellent filter manufacturing processability and excellent cigarette physical properties (e.g., draw resistance). DETAILED DESCRIPTION OF THE INVENTION

[0131] The functions and effects of the invention will be explained in more detail below through specific examples of the invention, but these are presented as examples of the invention and do not in any way limit the scope of the invention.

[0132] Examples and Comparative Examples Lyocell materials were produced through the processes described in the following examples and comparative examples. Unless otherwise specified, the conditions were within the scope of the above description.

[0133] Example 1 A spinning dope for producing tobacco filter tow with a concentration of 11 wt% was prepared by mixing cellulose pulp with an α-cellulose content of 93.9% and a degree of polymerization (DPw) of 820 with an N-methylmorpholine-N-oxide (NMMO) / HO solvent with a propyl gallate content of 0.01 wt%. The spinning dope was then spun from a spinning nozzle while maintaining a spinning temperature of 110°C and adjusting the discharge rate and spinning speed so that the filament single fiber fineness was 4.8 denier.

[0134] The filament-shaped spinning dope discharged from the spinning nozzle was fed through an air gap section to a coagulation liquid (containing 75 wt% water and 25 wt% N-methylmorpholine-N-oxide (NMMO) at a temperature of about 25°C) in a coagulation tank. At this time, the cooling air in the air gap section was at a temperature of 8°C and a flow rate of 200 Nm 3 The spinning dope was subjected to primary coagulation at an air flow rate of 1 / h. The concentration of the coagulation liquid was continuously monitored using a sensor and a refractometer.

[0135] The solidified lyocell filaments were then washed with water. Specifically, the filaments were introduced into a pulling roller, and N-methylmorpholine-N-oxide (NMMO) remaining in the filaments was removed with water sprayed from a water washing device. The washed filaments were then immersed in a bath designed to contain an oil concentration of 2 wt%.

[0136] The filament was pulled at 2 kgf / cm by a nip roll provided at the bath discharge section. 2 The fabric was then treated with pressure and placed in a crimping device to create wrinkles. Specifically, the crimping ratio (crimp draft ratio) was set to 1.1, and the steam pressure in the steam box was set to 0.5 kgf / cm. 2 The roller pressure of the crimping device was 2.5 kgf / cm 2 Adjust the blade pressure to 0.5kgf / cm 2 At this time, the crimping ratio was calculated as described above.

[0137] The produced tow was subjected to a secondary oil treatment to prevent static electricity and to impart flexibility, and immediately after the treatment, the tow was passed through a continuous dryer set at 120°C to obtain a dried tow product. The total fineness of the tow was as shown in Table 1.

[0138] Example 2 Lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the filament single yarn fineness was 5.0 denier and the crimping ratio was adjusted to 1.05 times. The total fineness of the tow was as shown in Table 1.

[0139] Example 3 Lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the filament single yarn fineness was 5.0 denier and the crimping ratio was adjusted to 1.2 times. The total fineness of the tow was as shown in Table 1.

[0140] Comparative Example 1 Lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the filament single yarn fineness was 4.0 denier and the crimping ratio was adjusted to 1.0. The total fineness of the tow was as shown in Table 1.

[0141] Comparative Example 2 Lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the filament single yarn fineness was 4.0 denier and the crimping ratio was adjusted to 1.35 times. The total fineness of the tow was as shown in Table 1.

[0142] Comparative Example 3 Lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the filament single yarn fineness was 4.0 denier and the crimping ratio was adjusted to 1.5 times. The total fineness of the tow was as shown in Table 1.

[0143] Comparative Example 4 Lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the single filament fineness was 8.5 denier. The total fineness of the tow was as shown in Table 1.

[0144] Evaluation or Measurement of Example Tows and Comparative Example Tows The following items were measured or evaluated for each of the Examples and Comparative Examples, and the results are shown in Table 1.

[0145] 1. Tow fineness (denier) A 2m sample of the tow to be measured is taken and left to stabilize for 24 hours in a room maintained at a constant temperature and humidity of 20°C and 65% humidity. One end of the stabilized tow is fixed, and a 2kg weight is attached to the other end. The tow is stretched by the load and maintained for 5 seconds (stabilization), after which it is cut to a length of 90cm to obtain a sample, and the weight of the sample is measured (total fineness). The fineness is converted to denier by multiplying the measured weight by 10,000. The single yarn fineness is calculated by dividing the total fineness by the number of filaments.

[0146] 2. Number of crimps Measurement is performed according to the KS K 0326 standard. Specifically, 20 tow samples with undamaged crimps are taken, and pre-prepared glossy paper pieces (25 mm clearance) are attached to each single fiber with a celluloid 4 to 5% amyl acetate adhesive so that the attached length is elongated by 25±5%, and then the adhesive is left to dry.

[0147] A crimp tester was used to apply an initial load equivalent to 1.96 / 1,000 cN (= 2 mgf) per De to each sample, and the number of crimps in a 25 mm interval was counted. The upper and lower limits of the number of crimps measured for 20 samples were then recorded.

[0148] 3. Crimp shape The crimp shape was measured by visually observing the shape of the sample through an optical microscope in the same manner as in the crimp count measurement. Specifically, it was checked whether the crimps were uniformly formed across the width of the sample, and classified as follows: Good: The crimp is uniform across the width of the sample. Poor: The crimp is not uniform across the width of the sample.

[0149] 4. Cigarette filter manufacturing process The tow was fed into a cigarette filter manufacturing facility, and the process sustainability was confirmed until the entire batch of samples was consumed.

[0150] 5. Cigarette filter drawing resistance and circumference Tobacco filter rods (650 mg) were manufactured using the tows prepared in the Examples and Comparative Examples. Specifically, the lyocell tows prepared in the Examples and Comparative Examples were wrapped with wrapping paper (6,500 CU porous paper) to produce cylindrical filter rods with an axial length of 120 mm and circumferences as shown in Table 1 below.

[0151] Then, based on the KS H ISO 6565 standard, the suction resistance and circumference of each rod were measured using a suction resistance tester and a circumference measuring instrument.

[0152] [Table 1]

[0153] As can be seen from Table 1, in the examples in which the tow production conditions are controlled according to the specific examples of the present application, the number of crimps is uniformly formed at an appropriate level, the cigarette filter production process is good, and the suction resistance of the filter can also be improved.

[0154] Specifically, in Comparative Example 1, the tow production conditions were inappropriate, so tow could not be produced and the filter performance could not be confirmed. In Comparative Examples 2 to 4, tow could be produced, but the tow shape was poor and the number of crimps was not uniform. As a result, the processability during cigarette filter production was not good, and the filter performance (draw resistance) was not as good as in the Examples.

Claims

1. spinning a lyocell dope; coagulating the spun lyocell dope to obtain a lyocell multifilament; Treating the lyocell multifilament with an oil; a crimping step of feeding the oil-treated lyocell multifilament into a crimping device so that pressure of steam and rollers is applied to the lyocell multifilament, The single filament fineness of the filament constituting the lyocell multifilament is more than 4.0 denier and not more than 8.0 denier, The crimping step is performed to satisfy a crimp draft ratio expressed by the following equation 1: [Formula 1] 1.01≦crimp draft ratio≦1.30 However, in the above formula 1, the crimp draft ratio is V １ / V ０ It is calculated as V ０ means the filament moving speed before the oil-treated multifilament is fed into the crimping device, and V １ means the passing speed of the filament gripped by the rollers in the crimping device.

2. 2. The method for producing a lyocell material for cigarette filters according to claim 1, wherein the method is carried out by controlling at least one of the spinning conditions of the amount of spinning dope discharged and the spinning speed so that the single filament fineness of the filament constituting the lyocell multifilament is more than 4.0 denier and not more than 8.0 denier.

3. The crimping step is performed by applying a pressure of 0.1 to 2.0 kgf / cm to the multifilament fed into the crimping device. ２ 2. The method for producing a lyocell material for cigarette filters according to claim 1, wherein the method is carried out while adding steam of 1000 kJ / min.

4. The crimping step uses a roller to apply a pressure of 1.5 to 4.0 kgf / cm to the multifilament fed into the crimping device. ２ 4. The method for producing a lyocell material for cigarette filters according to claim 3, wherein the method is carried out while applying a pressure of 1000 kJ / cm.sup.2 or more.

5. The crimping step uses a doctor blade to apply a pressure of 0.1 to 2.0 kgf / cm to the multifilament that has passed through the rollers of the crimping device. ２ 5. The method for producing a lyocell material for cigarette filters according to claim 4, wherein the method is carried out while applying a pressure of 1000 kJ / cm.sup.2 or more.

6. 2. The method for manufacturing a lyocell material for a cigarette filter according to claim 1, wherein the step of spinning the dope is performed while spinning a lyocell spinning dope containing cellulose pulp and N-methylmorpholine-N-oxide (NMMO).

7. 2. The method for producing a lyocell material for a cigarette filter according to claim 1, wherein the coagulation step of obtaining the lyocell multifilament includes a primary coagulation step of supplying cooling air to the spun lyocell dope, and a secondary coagulation step of introducing the primarily coagulated spinning dope into a coagulation liquid to coagulate it.

8. The primary solidification stage is carried out by applying air at a temperature of 15°C or less at a pressure of 70 to 300 Nm ３ 8. The method for producing a lyocell material for cigarette filters according to claim 7, wherein the method is carried out while supplying the lyocell dope with an air flow rate of 1000 / h.

9. 8. The method for manufacturing a lyocell material for a cigarette filter according to claim 7, wherein the secondary coagulation step is performed by introducing the primarily coagulated spinning dope into a coagulation liquid having a temperature of 30° C. or less.

10. 2. The method for manufacturing a lyocell material for a cigarette filter according to claim 1, further comprising the step of washing the solidified lyocell multifilament with water after the step of obtaining the multifilament and before the step of treating with oil.

11. 2. The method of claim 1, wherein the method provides a tow having 20 to 50 crimps per inch.

12. 12. The method for producing a lyocell material for cigarette filters according to claim 11, which provides a tow having a total fineness of 15,000 to 35,000 denier.

13. A crimped tow is manufactured by feeding a multifilament into a crimping device so that a crimp can be imparted under a condition that satisfies a crimp draft ratio expressed by the following Equation 1: having 20 to 50 crimps per inch; A lyocell material for cigarette filters having a total fineness of 15,000 to 35,000 denier: [Formula 1] 1.01≦crimp draft ratio≦1.30 However, in the above formula 1, the crimp draft ratio is V １ / V ０ It is calculated as V ０ means the filament moving speed before the multifilament is fed into the crimping device, and V １ means the passing speed of the filament gripped by the rollers in the crimping device.

14. spinning a lyocell dope; coagulating the spun lyocell dope to obtain a lyocell multifilament; Treating the lyocell multifilament with an oil; A crimping step of feeding the oil-treated lyocell multifilament into a crimping device so that pressure of steam and rollers is applied to the lyocell multifilament; and manufacturing a filter using the crimped tow; The single filament fineness of the filament constituting the lyocell multifilament is more than 4.0 denier and not more than 8.0 denier, The method for manufacturing a cigarette filter, wherein the crimping step is performed to satisfy a crimp draft ratio expressed by the following Equation 1: [Formula 1] 1.01≦crimp draft ratio≦1.30 However, in the above formula 1, the crimp draft ratio is V １ / V ０ It is calculated as V ０ means the filament moving speed before the oil-treated multifilament is fed into the crimping device, and V １ means the passing speed of the filament gripped by the rollers in the crimping device.

15. The resistance to suction measured by KS H ISO 6565 is 375 mmH ２ 15. A method for producing a cigarette filter according to claim 14, which provides a cigarette filter having a resistance to draw of 0 or more (wherein the resistance to draw is measured when a filter rod having a circumference within the range of 10 mm to 30 mm is produced).

16. The resistance to suction measured by KS H ISO 6565 is 810 mmH ２ 16. A method for producing a cigarette filter according to claim 15, which provides a cigarette filter having a resistance to draw of 0 or less, wherein the resistance to draw is measured when a filter rod having a circumference within the range of 10 mm to 30 mm is produced.

17. A cigarette filter containing lyocell material, The lyocell material is a crimped tow produced by feeding multifilaments into a crimping device so that crimping can be performed under a condition that satisfies a crimp draft ratio expressed by the following Equation 1: The tow has 20 to 50 crimps per inch and a total fineness of 15,000 to 35,000 denier. [Formula 1] 1.01≦crimp draft ratio≦1.30 However, in the above formula 1, the crimp draft ratio is V １ / V ０ It is calculated as V ０ means the filament moving speed before the multifilament is fed into the crimping device, and V １ means the passing speed of the filament gripped by the rollers in the crimping device.

18. The resistance to suction measured by KS H ISO 6565 is 375 mmH ２ 18. A cigarette filter according to claim 17, wherein the resistance to draw is 0 or more, the resistance being measured when a filter rod having a circumference within the range of 10 mm to 30 mm is produced.

19. The resistance to suction measured by KS H ISO 6565 is 810 mmH ２ 18. A cigarette filter according to claim 17, wherein the resistance to draw is 0 or less, where the resistance to draw is measured when a filter rod having a circumference within the range of 10 mm to 30 mm is produced.

20. 20. A cigarette filter according to claim 18 or 19, having a circumference of 19 mm or less.

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