JP2024523387A - Lyocell material for cigarette filters and its manufacturing method - Google Patents

Abstract

The present invention relates to a lyocell material for cigarette filters, which can realize filter properties equivalent to those of currently used CA cigarette filters, and which can ensure optimal processability for manufacturing cigarette filters by setting an optimal fineness range for crimped lyocell tow, and which is excellent in biodegradability and can reduce environmental pollution factors caused by conventional discarded cigarette butts, and a manufacturing method thereof.

Description

Cross-reference to related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0129846 dated September 30, 2021, and Korean Patent Application No. 10-2022-0118769 dated September 20, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

The present invention relates to a lyocell material for cigarette filters and a method for producing the same.

A typical cigarette filter contains cellulose acetate (CA) tow, which is made by extracting cellulose from wood pulp and acetylating it.

The cigarette filters are also incorporated into tobacco products, distributed to consumers, provided for smoking, and finally discarded after the cigarettes are smoked. The cigarette filters are also directly discarded as manufacturing residues from cigarette filter manufacturing plants. Such cigarette filter waste is collected as garbage and buried for disposal. In some cases, smoked cigarettes are not collected as garbage and are left in the natural environment.

To this end, in order to manufacture biodegradable cigarette filters, it has been proposed to add additives made of biodegradable polymers to cellulose acetate in order to increase its decomposition rate, to use cellulose acetate with a low degree of substitution to increase its biodegradability, or to use a composite material of highly biodegradable polymers such as PHB (poly-hydroxybutyrate)/PVB (polyvinyl butyral) and starch as the filter tow raw material.

Recently, research is being conducted to replace cellulose acetate tow with environmentally friendly materials in order to protect the natural environment and reduce costs. For example, unlike cellulose acetate, tow made from lyocell fibers, which are made by turning cellulose itself into fibers, is being developed.

However, no material has yet been developed that can reduce environmental pollution to the desired level and provide filtering performance at the same or higher level than the currently used CA cigarette filter material.

One embodiment of the present invention is to provide a lyocell material for cigarette filters and a manufacturing method thereof that utilizes lyocell material and can achieve cigarette filter performance at a level equivalent to that of currently used CA (cellulose acetate) products.

Another embodiment of the present invention provides a lyocell material for cigarette filters and a manufacturing method thereof that can reduce environmental pollution caused by waste from CA cigarette butts.

In this specification, in one embodiment,

(S1) spinning a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO);
(S2) coagulating the spun lyocell spinning dope to obtain a lyocell multifilament;
(S3) washing the obtained lyocell multifilament with water;
(S4) treating the washed lyocell multifilament with an oil agent;
(S5) crimping the oil-treated lyocell multifilament to obtain a crimped tow;
(S6) drying the crimped tow;
The step of obtaining the crimped tow includes a step of crimping the oil-treated lyocell multifilament so that a crimper draft ratio calculated by the following Equation 1 satisfies 1.01 to 1.3 times,
The crimp tow has a thickness range of 25,000 to 45,000 De.
A method for producing a lyocell material for cigarette filters is provided, comprising:
[Formula 1]
Crimper draft ratio = V1/V0
In the above formula 1, V0 is the speed (V0) immediately before the oil-treated lyocell multifilament is fed into the Crimper M/C, and V1 is the roller rotation speed of the Crimper M/C for crimping the oil-treated lyocell multifilament.

In addition, in another embodiment, the present specification includes a crimped tow formed using a lyocell multifilament spun from a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO),
The crimped tow provides a lyocell material for cigarette filters, which is a lyocell tow having a thickness range of 25,000 to 45,000 De.

The present specification also provides a cigarette filter that includes the lyocell material for cigarette filters.

The following is a detailed description of the lyocell material for cigarette filters and its manufacturing method according to an embodiment of the invention.

Unless otherwise expressly stated, in this specification, the terminology is intended to refer only to specific embodiments and is not intended to limit the invention.

As used herein, the singular forms include the plural forms unless the context clearly indicates to the contrary.

As used herein, "comprise" means to embody certain properties, regions, integers, steps, operations, elements, and/or components, but does not exclude the presence or inclusion of other certain properties, regions, integers, steps, operations, elements, components, and/or groups.

As used herein, the terms "at least one" or "one or more" should be understood to include all possible combinations of one or more of the associated items.

The present invention will be described in detail below.

According to one embodiment of the invention for manufacturing a lyocell material ,

(S1) spinning a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO);
(S2) coagulating the spun lyocell spinning dope to obtain a lyocell multifilament;
(S3) washing the obtained lyocell multifilament with water;
(S4) treating the washed lyocell multifilament with an oil agent;
(S5) crimping the oil-treated lyocell multifilament to obtain a crimped tow;
(S6) drying the crimp tow;
The step of obtaining the crimped tow includes a step of crimping the oil-treated lyocell multifilament so that a crimper draft ratio calculated by the following Equation 1 satisfies 1.01 to 1.3 times, and the crimped tow has a diameter range of 25,000 to 45,000 De:
[Formula 1]
Crimper draft ratio = V1/V0
In the above formula 1, V0 is the speed (V0) immediately before the oil-treated lyocell multifilament is fed into the Crimper M/C, and V1 is the roller rotation speed of the Crimper M/C for crimping the oil-treated lyocell multifilament.

The present invention aims to provide a lyocell material for cigarette filters and a method for producing the same, which can be used to produce cigarette filter tow using highly biodegradable lyocell and can replace conventionally used cigarette filter materials.

In addition, the present invention utilizes this lyocell material to produce tow for cigarette filters that is highly biodegradable and can achieve cigarette filter performance at the same level as currently used CA (cellulose acetate) products.

Specifically, the present invention can set the optimal fineness range of crimped lyocell tow, which can achieve filter properties equivalent to those of currently used CA, by adjusting the crimper draft ratio during the crimping process when producing lyocell tobacco filter tow, and ensure optimal processability for cigarette filter production.

According to one embodiment of the invention, in the crimping process, the lyocell tobacco filter tow can be subjected to a process draft condition of 1.01 to 1.3 times the filament in order to impart uniform crimping.

During the above crimping, the draft ratio at the crimper can be calculated using the following formula 1:

[Formula 1]
Crimper draft ratio = V1/V0

In the above formula 1, V0 is the speed (V0) just before feeding into the Crimper M/C, and V1 is the roller rotation speed of the Crimper M/C for crimping the oil-treated lyocell multifilament.

The above-mentioned Crimper M/C means a crimp machine.

At this time, if the crimper draft ratio is less than 1.01 times, the tension of the filament tow fed into the crimper is not stable, resulting in a non-uniform crimp. If it is 1.3 times or more, excessive crimping is given to the filaments fed into the crimper, resulting in physical embrittlement, or a problem that a uniform crimp cannot be given to the left and right side edges of the tow due to changes in filament width.

To achieve the physical properties of a cigarette filter, the tow has a crimp count range of 25 to 50 pieces per inch (ea/inch).

In addition, and finally, lyocell tow is characterized by a thickness range (i.e., fineness) of 25,000 to 45,000 De for optimal cigarette filter performance.

In this case, when the thickness of the lyocell tow is less than 25,000 denier (De) or exceeds 45,000 denier (De), it is difficult to ensure the processability and physical properties of the cigarette filter. Such a lyocell tow fineness can be achieved by adjusting the single fineness of the lyocell multifilament to a range of 2.0 to 2.8 denier during the spinning process, along with adjusting the crimper draft ratio.

In addition, cigarette filters according to an embodiment of the invention are generally divided into regular type and ultra-slim type, but the present invention can be applied to regular type cigarette filters.

Cigarette filters manufactured using this tow can achieve the draw resistance required for a variety of cigarettes, and can uniformly achieve the physical properties required for cigarette filters (filter circumference, draw resistance).

The following describes in more detail each step of the method for producing lyocell material for cigarette filters according to the present invention.

[Step (S1)]
In the present invention, step (S1) is a step of spinning a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO). The lyocell spinning dope contains 8 to 13 wt % of cellulose pulp and 87 to 92 wt % of an aqueous solution of N-methylmorpholine-N-oxide, and the cellulose pulp has an α-cellulose content of 85 to 97 wt % and a degree of polymerization (DPw) of 600 to 1,700.

If the cellulose pulp content is less than 8% by weight, it is difficult to realize fibrous properties, and if it exceeds 13% by weight, it is difficult to dissolve in an aqueous solution. In addition, if the content of the N-methylmorpholine-N-oxide aqueous solution is less than 87% by weight, the dissolution viscosity becomes excessively high, which is undesirable, and if it exceeds 92% by weight, the spinning viscosity becomes excessively low, making it difficult to produce uniform fibers in the spinning stage.

In the aqueous solution of N-methylmorpholine-N-oxide, the weight ratio of N-methylmorpholine-N-oxide to water is 93:7 to 85:15. If the weight ratio of N-methylmorpholine-N-oxide to water exceeds 93:7, the dissolution temperature becomes high and cellulose decomposition occurs during dissolution of cellulose. If the weight ratio is less than 85:15, the dissolving ability of the solvent decreases, making it difficult to dissolve cellulose.

The spinning dope is used and discharged from a spinning nozzle having a flat or doughnut-shaped spinneret. At this time, the spinneret serves to discharge the filament-shaped spinning dope as a coagulation liquid in the coagulation tank through an air gap section. The step of discharging the spinning dope from the spinneret can be performed at 100 to 120°C.

In addition, in the step (S1), the discharge amount and spinning speed are adjusted to spin the lyocell multifilament so that the single fineness of the lyocell multifilament is 2.0 to 2.8 denier. Specifically, when spinning the lyocell filament, by adjusting the clamp draft ratio as described below and spinning the single fineness of the lyocell multifilament within the above range, it is possible to prevent deterioration of the cigarette filter processability and more effectively achieve the physical properties required by the industry.

[Step (S2)]
In the present invention, the step (S2) is a step of solidifying the lyocell spinning dope spun in the step (S1) to obtain a lyocell multifilament, and the solidification in the step (S2) includes a primary solidification step by air quenching (Q/A) in which cooling air is supplied to the spinning dope to solidify it, and a secondary solidification step in which the primarily solidified spinning dope is immersed in a coagulation liquid to solidify it.

In step (S1), after the spinning dope is discharged through the flat or doughnut-shaped nozzle, it can be passed through an air gap section in the space between the spinning dope and the coagulation tank. In the case of a flat nozzle, cooling air is supplied from one side of the nozzle to the opposite direction in the air gap section, and in the case of a doughnut-shaped nozzle, cooling air is supplied from the inside of the nozzle to the outside from an air cooling section located on the inside, and a suction function can also be added to the opposite side or outside. The spinning dope can be primarily coagulated by air quenching, which supplies the spinning dope with such cooling air.

The lyocell multifilament used in the coagulation step (S2) has a single denier of 2.0 to 2.8.

At this time, factors affecting the physical properties of the lyocell multifilament obtained in step (S2) are the temperature and wind speed of the cooling air in the air gap section, and the solidification in step (S2) is performed by supplying cooling air at a temperature of 4 to 15°C and a wind volume of 50 to 250 L/ ^m3 to the spinning dope.

During the primary solidification, if the temperature of the cooling air is less than 4°C, the die surface temperature will be low, the cross section of the lyocell multifilament will be non-uniform, and the spinning process will be poor; if it exceeds 15°C, the primary solidification by the cooling air will not be sufficient, and the spinning process will be poor.

In addition, if the volume of cooling air during primary solidification is less than 50 L/ ^m3 , primary solidification by the cooling air is not sufficiently performed, the spinning process becomes poor, and fiber breakage occurs. If the volume of cooling air exceeds 250 L/ ^m3 , the spinning dope discharged from the spinneret is shaken by the air, resulting in poor spinning process.

After the primary solidification by air quenching, the spinning dope is supplied to a coagulation tank containing a coagulation liquid, where the secondary solidification can proceed. In order to ensure that the secondary solidification proceeds properly, the temperature of the coagulation liquid is 30°C or less. This is to ensure that the secondary solidification temperature is not higher than necessary and that the coagulation rate is maintained properly. Here, the coagulation liquid is not particularly limited, as it is manufactured and used with a normal composition in the technical field to which the present invention pertains.

[Step (S3)]
In the present invention, step (S3) is a step of washing the lyocell multifilament obtained in step (S2) with water. More specifically, the lyocell multifilament obtained in step (S2) is introduced into a pulling roller and then introduced into a water washing tank to wash it with water.

In the washing step of the filament, a washing solution having a temperature of 0 to 100°C can be used, taking into consideration the ease of recovery and reuse of the solvent after washing. The washing solution can be water, and can further contain other additives if necessary.

[Step (S4)]
In the present invention, step (S4) is a step of treating the lyocell multifilament washed with water in step (S3) with an oil agent.

For the oil treatment, a method of immersing the filament tow in a bath in which the oil has been made up and then discharging it can be used.

The oil treatment is carried out so that the multifilament is completely immersed in the oil, and the amount of oil applied to the filament is kept constant by squeezing rollers attached to the inlet roll and outlet roll of the oil treatment device.

The oil used to coat the filaments is different from that used for general fibers, and can be one that has been developed specifically for lyocell.

According to a preferred embodiment, the oil imparts a lubricating function that can uniformly impart the physical properties of the cigarette filter tow, and an appropriate level of smoothness and adhesion, thereby optimizing the filter manufacturing process. In order to minimize the phenomenon in which the filter shape is deformed by the smoker's saliva during smoking and the filter hardness is reduced, the oil imparts hydrophobicity that can delay the penetration of saliva into the filter, thereby slowing down the rate at which the filter hardness is reduced. In addition, even if a certain amount of the oil remains in the cigarette filter, it can be composed of ingredients that are harmless to the smoker's body.

However, the oil reduces friction that occurs when the filaments come into contact with the drying rollers and guides during the crimping stage, and helps to ensure good crimping between the fibers. There are no particular restrictions on the type of oil, so long as it is one that is commonly used in the manufacture of lyocell filaments.

In one preferred example, the oil agent includes one or more components selected from the group consisting of a lubricating component, a cohesion component, a smoothness component, and a hydrophobic component.

The oil may be used so that the oil content relative to the lyocell multifilament is maintained at a concentration of 2 to 8% by weight, or 3 to 7% by weight. Maintaining the oil content within this range reduces friction that occurs when the lyocell multifilament comes into contact with the device during the crimping step, and allows inter-fiber crimps to be formed well.

[Step (S5)]
Step (S5) is a step of crimping the lyocell multifilament treated with oil in step (S4) to obtain a crimped tow.

Specifically, the method involves the step of crimping the oil-treated lyocell multifilament by applying steam and pressure, and after step (S5), a crimped tow can be obtained.

The term "crimping" used throughout this specification primarily refers to the application of wrinkles to filaments to impart a bulk feel to the fibers. The crimping process in the present invention may be performed through a stuffer box equipped with a press roller. The press roller may also be a nip roller.

The lyocell tow for cigarette filters presented in this invention has a range of crimper draft ratios during the tow manufacturing process to achieve optimal filter properties.

According to a preferred embodiment, in the crimping process, the lyocell tobacco filter tow may be subjected to a process draft condition of 1.01 to 1.3 times the filament calculated by Equation 1 in order to impart crimping.

The crimper draft conditions also change the machine conditions for uniform crimping, and the change factors adjust the pressure supplied to the steam box in front of the crimper, the pressure applied to the crimper rolls, and the pressure conditions of the doctor blade.

For example, a steam box for steam treatment of the filament tow is provided upstream of the stuffer box, and the steam pressure supplied to the steam box can be controlled to satisfy the following conditions: 0.1 to 3.0 kgf/ ^cm2 , the pressure applied to the press roller of the crimping device can be controlled to satisfy the following conditions: 1.5 to 4 kgf/ ^cm2 , and the doctor blade pressure can satisfy the following conditions: 0.1 to 3 kgf/ ^cm2 . By controlling the above conditions, a uniform crimp can be applied.

If the steam pressure is less than 0.1 kgf/ ^cm2 , the modulus of the filaments is not reduced to a level suitable for the process, and crimps are not smoothly formed. If the steam pressure exceeds 3.0 kgf/ ^cm2 and an excessively large amount of steam is supplied, the modulus of the filaments can be minimized, but the required number of crimps cannot be uniformly imparted due to the excessive moisture content.

In addition, if the pressure applied by the press rollers is less than 1.5 kgf/ ^cm2 , the thickness of the input filament cannot be uniformly imparted, and the desired number of crimps cannot be uniformly formed. If the pressure exceeds ⁴ kgf/cm2, the pressing force is so strong that the content of water or oil in the tow is rapidly reduced, and the filament cannot smoothly pass through the stuffer box. In addition, it is preferable that the gap between the press rollers is maintained at 0.01 to 3.0 mm. If the gap between the press rollers is less than 0.01 mm, the pressure of the filament by the rollers becomes too high, making it impossible to form a crimp, or after formation, damage occurs due to surface friction of the filament. If the gap exceeds 3.0 mm, a filament slip phenomenon occurs between the press rollers, making it difficult to form a uniform crimp.

In addition, the doctor blade moves up and down to provide uniform crimping after passing through the press roller. If the pressure of the doctor blade is less than 0.1 kgf/ ^cm2 , the upper plate is not fixed due to the pressure inside the stuffer box, and the tow is retained in the stuffer box for a long period of time, so that the continuity of the process is not maintained or the appropriate retention time cannot be provided, making it impossible to control the desired number of crimps of the tow. If the pressure exceeds 3.0 kgf/ ^cm2 , the tow is not smoothly discharged into the stuffer box, resulting in an irregular crimp shape.

Under such conditions, the crimped tow can secure and maintain 25 to 50 crimps/inch, or 30 to 45 crimps/inch. When it is formed into a filter rod with a mono filter diameter and a composite filter diameter of 24.2 mm and 24.5 mm, it can show a draw resistance of about 240 to 590 PD ( _mmH2O ) according to the KS H ISO 6565 measurement standard. The filter is applied with various draw resistance values depending on the cigarette product. Thus, the lyocell crimped tow of the present invention is not only environmentally friendly because it is biodegraded and removed within a short time, but also can satisfy the required physical properties such as draw resistance, filter strength, filter removal ability, etc. more effectively than before when it is manufactured into a cigarette filter, and can maximize its effect.

[Step (S6)]
Step (S6) is a step of drying the crimped tow obtained in step (S5) at a constant temperature.

Specifically, the oil that is uniformly soaked into the filament tow in the oil treatment bath is picked up to a level that allows a uniform number of crimps to be imparted in the crimping process.

The crimped tow is then dried through a continuous drying device to produce the final Lyocell crimped tow that contains a uniform amount of oil.

The step of drying the crimped tow can be carried out using a continuous drying device at 105 to 135°C for 15 to 45 minutes, or at 110 to 130°C for 20 to 40 minutes.

If the drying temperature is below 105°C, the tow is not completely dried and the moisture content cannot be adjusted to the required level, and if it is above 135°C, yellowing occurs, resulting in a low whiteness. If the drying time is less than 15 minutes, irregular undried areas are produced, and if it is more than 45 minutes, excessive drying time causes damage to the tow surface and yellowing occurs, resulting in a low whiteness.

After the drying process, the final tow produced may have a thickness range of 25,000 to 45,000 denier (De) for lyocell tow for cigarette filters.

In this case, when the thickness range of the lyocell tow is less than 25,000 De or more than 45,000 De, it is difficult to ensure the processability and physical properties of the cigarette filter.

The thickness range of the lyocell tow can be obtained by adjusting the single fineness of the lyocell multifilament to a range of 2.0 to 2.8 denier in the spinning process in step (S1) and by adjusting the crimper draft ratio in step (S5).

Lyocell Material for Cigarette Filters According to another embodiment of the present invention, a lyocell material for cigarette filters may be provided, which includes a crimped tow formed using a lyocell multifilament spun from a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO), and the crimped tow is a lyocell tow having a thickness in the range of 25,000 to 45,000 De.

The number of crimps in the lyocell tow can be formed to be 25 to 50 per inch.

The lyocell spinning dope also contains 8 to 13% by weight of cellulose pulp and 87 to 92% by weight of an aqueous solution of N-methylmorpholine-N-oxide.

The cellulose pulp has an α-cellulose content of 85 to 99% by weight and a degree of polymerization (DPw) of 600 to 1,700.

In another embodiment of the present invention, a cigarette filter can be provided that contains the lyocell material for cigarette filters as lyocell tow.

The tobacco filter is not limited in its composition, except for the lyocell tow.

For example, the cigarette filter may include a cylindrical lyocell tow containing a plurality of lyocell fibers, a plasticizer, a hardener, and the like.

The plurality of lyocell fibers can be connected to each other by a hardener, and can exhibit an interconnected structure in which the fiber surfaces are in contact with the hardener.

The hardener is a well-known substance used to improve filter hardness. For example, the hardener may include polymer resins such as cellulose derivatives, vinyl derivatives, vinyl emulsion resins, natural polymers including sodium alginate, starch, and starch derivatives.

Therefore, the present invention can provide a lyocell tobacco filter tow that can achieve the same level of filter performance (manufacturing processability, filter properties) as CA, a currently used cigarette filter material. In addition, this specification also describes how currently used CA cigarette butts (filters) can be manufactured using a more environmentally friendly method than conventional methods.

In addition, by applying the lyocell tow produced by the above-mentioned method, regular-type cigarette filters can be produced uniformly, and the required physical properties (filter circumference, drawing resistance) can be uniformly achieved.

According to the present invention, it is possible to set the optimal fineness range of crimped lyocell tow that can achieve filter properties equivalent to those of CA, a currently used cigarette filter, and ensure optimal processability for cigarette filter manufacturing.

In addition, cigarette filters manufactured using the lyocell tow can achieve the draw resistance required for a variety of cigarettes, and can express their physical properties (filter circumference, draw resistance).

In addition, the present invention provides lyocell tow in an environmentally friendly manner, thereby replacing conventional CA cigarette filters and reducing the environmental pollution caused by discarded cigarette butts.

In other words, the present invention is excellent in biodegradability, processability, and physical properties, and can replace conventional cigarette filter materials, demonstrating economical benefits.

The present invention will be described in more detail below with reference to examples. However, the following examples are merely intended to aid in the understanding of the present invention and are not intended to limit the scope of the invention.

Example 1
A cellulose pulp having a degree of polymerization (DPw) of 820 and an α-cellulose content of 93.9% was mixed with a mixed solvent of N-methylmorpholine-N-oxide (NMMO)/H ₂ O (weight ratio: 90/10) having a propyl gallate content of 0.01% by weight to prepare a spinning dope for producing a tow for cigarette filters having a concentration of 12% by weight. First, the spinning dope was spun in a spinning nozzle while maintaining a spinning temperature of 110° C. and adjusting the discharge amount and spinning speed so that the filament fineness was 2.4 denier.

The filament-shaped spinning dope discharged from the spinning nozzle was supplied to the coagulation liquid in the coagulation tank through the air gap section. In the air gap section, the spinning dope was primarily coagulated with cooling air at a temperature of 8°C and an air volume of 100 L/ ^m3 . The coagulation liquid had a temperature of 25°C and a concentration of 75% by weight of water and 25% by weight of N-methylmorpholine-N-oxide (NMMO). The concentration of the coagulation liquid was continuously monitored using a sensor and a refractometer.

The filaments solidified by the pulling rollers were washed with water sprayed from a water washing device to remove any N-methylmorpholine-N-oxide (NMMO) remaining in the filaments.

The water-washed filament was then immersed in an oil treatment bath with a make-up of 2% oil by weight.

The filaments immersed in the bath were treated at a pressure of 2 kgf/ ^cm2 using a nip roller installed at the discharge part of the bath, and then fed into a Crimper M/C for crimping.

At this time, the crimping ratio, i.e., the crimper draft ratio, was set to 1.1 times, steam was supplied to the steam box at 0.3 kgf/ ^cm2 , the crimp M/C roller pressure was set to 2.5 kgf/ ^cm2 , and the doctor blade pressure was set to 1.0 kgf/ ^cm2 to produce the tow. The produced tow passed through a continuous drying device set at 120°C to obtain a dried tow product.

The obtained tow was used to manufacture a cigarette filter having a target regular filter suction resistance of 450±12% mmH ₂ O.

Example 2
A lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the monofilament size was 2.6 denier and the crimper draft ratio was 1.05 times.

Example 3
A lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the monofilament size was 2.8 denier and the crimper draft ratio was 1.2 times.

Comparative Example 1
A lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the crimper draft ratio was adjusted to 1.0 times.

Comparative Example 2
A lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the crimper draft ratio was adjusted to 1.35 times.

Comparative Example 3
A lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the crimper draft ratio was adjusted to 1.5 times.

Comparative Example 4
A lyocell tow for cigarette filters was produced in the same manner as in Example 1, except that the monofilament size was 3.0 denier and the crimper draft ratio was 1.1 times.

[Experimental Example]
For the lyocell tows of the Examples and Comparative Examples, the tow physical properties were measured by the following methods, and the results are shown in Table 1.

Physical property measurement method (1) Tow fineness measurement A 2m sample of the tow to be measured is taken and left in a constant temperature and humidity room at a temperature of 20°C and a humidity of 65% for 24 hours. One end of the stabilized tow is fixed, and a weight of 2 kg is attached to the other end. The tow in the elongated state by the load is stabilized for 5 seconds, and then cut to 90 cm to obtain a sample, and the weight is measured. The tow fineness is converted to the weight measured by the denier conversion method x 10,000.

(2) Crimp Count Measurement: After taking 20 samples with undamaged crimps measured according to the KS K 0326 standard, a glossy test piece (with a clearance of 25 mm) was prepared in advance and attached to each single fiber with a 4-5% celluloid amyl acetate adhesive so that the fiber was stretched 25±5% of the attachment length, and then the adhesive was left to dry. A crimp tester was used to apply an initial load equivalent to 1.96/1,000cN (=2mgf) per De to each sample, and the number of crimps at 25 mm was calculated, and the average value was shown excluding the decimal point.

(3) Crimp Shape Measurement The crimp shape was measured by sampling in the same manner as in measuring the number of crimps, and then visually inspecting the uniformity using an optical microscope.

(4) Tobacco filter manufacturing processability Tobacco filter manufacturing processability was confirmed by feeding tow into a tobacco filter manufacturing facility and confirming process maintainability until one batch of samples was completely consumed.

(5) Measurement of draw resistance and circumference of cigarette filter Tobacco filter rods were manufactured using the tows manufactured through the above-mentioned Examples and Comparative Examples, and the draw resistance of each rod was measured using a draw resistance and circumference measuring device according to the KS H ISO 6565 standard.

As shown in Table 1, in the cases of Examples 1 to 3, the number of crimps was uniformly formed due to the tow manufacturing conditions, and the tow manufactured by setting the equipment conditions during cigarette filter manufacturing was able to achieve the physical properties required for cigarette filters.

However, in the case of Comparative Example 1, the tow production conditions were not appropriate, and even with the conditions set during the manufacturing process, it was not possible to produce tow, and the filter performance could not be confirmed.

In the cases of Comparative Examples 2 to 4, tow could be produced, but due to unreasonable production conditions, it was difficult to produce uniform tow.

That is, Comparative Examples 1 to 3 were outside the crimper draft ratio range of the present invention, and therefore it was impossible to produce a tow, or even if a tow was produced, the crimp shape was poor and continuous production of cigarette filters was impossible, and as a result, the drawing resistance was lower than in the Examples. In addition, in Comparative Example 4, the filament single fineness during spinning using the spinning dope was 3.0 denier, which is beyond the filament single fineness range of the present invention, and the tow fineness range was over 4,000 denier (De), and it was confirmed that the processability and physical properties of the cigarette filter were inferior to those of Examples 1 to 3.

Therefore, in the comparative example, it was confirmed that when the produced tow was used to manufacture cigarette filters, the processability could not be maintained due to the non-uniformity of the tow, and it was difficult to achieve filter performance due to the non-uniformity of the tow.

Meanwhile, in the first to third embodiments, the crimper draft ratio can be adjusted in the crimping process during the preparation of the lyocell tobacco filter tow to achieve optimal cigarette filter performance, resulting in a thickness range of 25,000 to 45,000 De. Thus, the present invention provides a crimped lyocell tow that can achieve cigarette filter physical properties equivalent to those of currently used CA, thereby ensuring optimal processability for cigarette filter preparation.

Claims (14)

(S1) spinning a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO);
(S2) coagulating the spun lyocell spinning dope to obtain a lyocell multifilament;
(S3) washing the obtained lyocell multifilament with water;
(S4) treating the washed lyocell multifilament with an oil agent;
(S5) crimping the oil-treated lyocell multifilament to obtain a crimped tow;
(S6) drying the crimped tow;
The step of obtaining the crimped tow includes a step of crimping the oil-treated lyocell multifilament so that a crimper draft ratio calculated by the following Equation 1 satisfies 1.01 to 1.3 times,
The crimped tow has a thickness range of 25,000 to 45,000 De.
[Formula 1]
Crimper draft ratio = V1/V0
In the above formula 1, V0 is the speed (V0) immediately before the oil-treated lyocell multifilament is fed into the Crimper M/C, and V1 is the roller rotation speed of the Crimper M/C for applying the oil-treated lyocell multifilament. The method for manufacturing a lyocell material for cigarette filters according to claim 1, wherein the lyocell multifilament in step (S2) has a single fineness of 2.0 to 2.8 denier. The method for manufacturing a lyocell material for cigarette filters according to claim 1, wherein the number of crimps in the lyocell tow is 25 to 50 per inch. The method for manufacturing a lyocell material for a cigarette filter according to claim 1, wherein the step (S5) is performed through a stuffer box of a crimping device. The method for producing the lyocell material for cigarette filters according to claim 4, wherein the stuffer box is controlled to satisfy the following conditions: steam pressure is 0.1-3.0 kgf/ ^cm2 , pressure applied to the press roller of the crimping device is 1.5-4 kgf/ ^cm2 , and pressure of the doctor blade is 0.1-3.0 kgf/ ^cm2 . The method for manufacturing a lyocell material for cigarette filters according to claim 1, wherein the step of drying the crimped tow in step (S6) is carried out using a continuous drying device at 105 to 135°C for 15 to 45 minutes. 2. The method of claim 1, wherein the solidification step (S2) is performed by supplying cooling air at a temperature of 4 to 15° C. and a volume of 50 to 250 L/ ^m3 to the spinning dope. The method for producing a lyocell material for cigarette filters according to claim 1, wherein the lyocell spinning dope in step (S1) contains 8 to 13% by weight of cellulose pulp and 87 to 92% by weight of an aqueous solution of N-methylmorpholine-N-oxide. The method for producing a lyocell material for cigarette filters according to claim 1, wherein the cellulose pulp has an α-cellulose content of 85 to 99% by weight and a degree of polymerization (DPw) of 600 to 1,700. A crimped tow formed using a lyocell multifilament spun from a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO),
The crimped tow is a lyocell tow having a thickness range of 25,000 to 45,000 De. The lyocell material for cigarette filters according to claim 10, wherein the number of crimps in the crimped tow is 25 to 50 per inch. The lyocell material for cigarette filters according to claim 10, wherein the lyocell spinning dope contains 8 to 13% by weight of cellulose pulp and 87 to 92% by weight of an aqueous solution of N-methylmorpholine-N-oxide. The lyocell material for cigarette filters according to claim 10, wherein the cellulose pulp has an α-cellulose content of 85 to 99% by weight and a degree of polymerization (DPw) of 600 to 1,700. A cigarette filter comprising the lyocell material for cigarette filters according to any one of claims 10 to 13.