LYOCELL MATERIAL FOR CIGARETTE FILTER AND METHOD FOR MANUFACTURING SAME

Abstract

The present disclosure relates to a lyocell material for a cigarette filter and a method of manufacturing the same, in which, by setting the optimal total denier range of crimped lyocell tow, which may realize filter properties equivalent to cellulose acetate (CA) currently used as a cigarette filter, the optimal processability for manufacturing a cigarette filter may be secured, and due to the excellent biodegradability thereof, environmental pollution factors caused by conventional discarded cigarette butts may be reduced.

Claims

1. A method of manufacturing a lyocell material for a cigarette filter, the method comprising: (S1) spinning a lyocell spinning dope comprising cellulose pulp and an N-methylmorpholine-N-oxide (NMMO) aqueous solution; (S2) coagulating the lyocell spinning dope spun in the step (S1) to obtain lyocell multi-filaments; (S3) water-washing the lyocel multifilaments obtained in the step (S2); (S4) oil-treating the lyocell multi-filaments water-washed in the step (S3); (S5) crimping the lyocell multifilaments oil-treated in the step (S4) to obtain a crimped tow; and (S6) drying the crimped tow, wherein the step (S5) is performed by crimping the lyocell multifilaments oil-treated in the step (S4) at the crimper draft ratio of 1.01 to 1.3 calculated by Equation 1 below, and the crimped tow has a fineness range of 25000 to 45000 De:
Crimper draft ratio=V1/V0[Equation 1] wherein in Equation 1, V0 is a speed immediately before feeding the oil-treated lyocell multi-filaments to a crimper M/C, and V1 is a roller rotation speed of the crimper M/C to provide crimps to the oil-treated lyocell multi-filaments.

2. The method of claim 1, wherein the lyocell multi-filaments obtained in the step (S2) have a single fiber fineness of 2.0 to 2.8 denier.

3. The method of claim 1, wherein the lyocell tow is formed to have a number of crimps of 25 to 50 per inch.

4. The method of claim 1, wherein the step (S5) is performed by using a stuffer box of the crimper M/C.

5. The method of claim 4, wherein the stuffer box is controlled to satisfy conditions of a steam pressure of 0.1 to 3.0 kgf/cm.sup.2, a pressure of 1.5 to 4 kgf/cm.sup.2 applied to a press roller of the crimper M/C, and a doctor blade pressure of 0.1 to 3.0 kgf/cm.sup.2.

6. The method of claim 1, wherein the drying of the crimped tow obtained in step (S6) is performed by using a continuous drying device at a temperature of 105 to 135? C. for 15 minutes to 45 minutes.

7. The method of claim 1, wherein the coagulating in step (S2) is performed by supplying cooling air to the spinning dope at a temperature of 4 to 15? C. and at an airflow rate of 50 to 250 L/m.sup.3.

8. The method of claim 1, wherein the lyocell spinning dope of (S1) comprises 8 to 13 wt % of the cellulose pulp and 87 to 92 wt % of the N-methylmorpholine-N-oxide aqueous solution.

9. The method of claim 1, wherein the cellulose pulp comprises 85 to 99 wt % of alpha-cellulose and has a degree of polymerization (DPw) of 600 to 1700.

10. A lyocell material for a cigarette filter, comprising a crimped tow formed of lyocell multi-filaments spun from a lyocell spinning dope comprising cellulose pulp and an N-methylmorpholine-N-oxide (NMMO) aqueous solution, wherein the crimped tow has a fineness range of 25000 to 45000 De.

11. The lyocell material for a cigarette filter of claim 10, wherein the crimped tow is formed to have a number of crimps of 25 to 50 per inch.

12. The lyocell material for a cigarette filter of claim 10, wherein the lyocell spinning dope comprises 8 to 13 wt % of the cellulose pulp and 87 to 92 wt % of the N-methylmorpholine-N-oxide aqueous solution.

13. The lyocell material for a cigarette filter of claim 10, wherein the cellulose pulp comprises 85 to 99 wt % of alpha-cellulose and has a degree of polymerization (DPw) of 600 to 1700.

14. A cigarette filter comprising the lyocell material for a cigarette filter according to claim 10.

Description

BEST MODE

[0099] Hereinafter, the present disclosure will be described in more detail with reference to the following examples. However, the following examples are merely presented to exemplify the present disclosure, and the scope of the present disclosure is not limited thereto.

Example 1

[0100] Cellulose pulp having a degree of polymerization (DPw) of 820 and including 93.9% of alpha-cellulose was mixed with a NMMO/H.sub.2O mixed solvent (weight ratio of 90/10) including 0.01 wt % of propyl gallate to prepare a spinning dope for preparing a tow for a cigarette filter with a concentration of 12 wt %. First, the spinning dope was maintained at a spinning temperature of 110? C. in a spinning nozzle and spun by adjusting a discharge amount and a spinning rate such that a single fiber fineness of filaments was adjusted to 2.4 De.

[0101] The spinning dope in the form of filaments discharged from the spinning nozzle was supplied to a coagulation solution contained in a coagulation bath through an air gap zone. In this case, the spinning dope was primarily coagulated in the air gap zone using cooling air at a temperature of 8? C. and an airflow rate of 100 L/m.sup.3. A coagulation solution including 75 wt % of water and 25 wt % of NMMO was used at 25? C. In this case, a concentration of the coagulation solution was continuously monitored by using a sensor and a refractometer.

[0102] The coagulated filaments were washed by a water-wash solution sprayed by a water-washing device via a draw roller to remove NMMO remaining in the filaments.

[0103] Subsequently, the water-washed filaments were immersed in an oil bath made-up of 2 wt % of oil.

[0104] The filaments immersed in the bath were treated at a pressure of 2 kgf/cm.sup.2 by using a nip roller provided at a release portion of the bath and fed into a crimper M/C to form crimps.

[0105] In this regard, a ratio of providing crimps, i.e., crimper draft ratio, was set to 1.1 times, the tow was prepared by supplying steam to the steam box at 0.3 kgf/cm.sup.2, setting a roller pressure of the crimper M/C roller to 2.5 kgf/cm.sup.2, and setting a doctor blade pressure to 1.0 kgf/cm.sup.2. The prepared tow passed through a continuous drying device set to a temperature of 120? C. to obtain a dried tow product.

[0106] The obtained tow was used to prepare a filter for a cigarette filter by targeting a regular filter suction resistance of 450?12% (mmH.sub.2O).

Example 2

[0107] A lyocell tow for a cigarette filter was prepared in the same manner as in Example 1, except that the single fiber fineness was adjusted to 2.6 De, and the crimper draft ratio was adjusted to 1.05 times.

Example 3

[0108] A lyocell tow for a cigarette filter was prepared in the same manner as in Example 1, except that the single fiber fineness was adjusted to 2.8 De, and the crimper draft ratio was adjusted to 1.2 times.

Comparative Example 1

[0109] A lyocell tow for a cigarette filter was prepared in the same manner as in Example 1, except that the crimper draft ratio was adjusted to 1.0 times.

Comparative Example 2

[0110] A lyocell tow for a cigarette filter was prepared in the same manner as in Example 1, except that the crimper draft ratio was adjusted to 1.35 times.

Comparative Example 3

[0111] A lyocell tow for a cigarette filter was prepared in the same manner as in Example 1, except that the crimper draft ratio was adjusted to 1.5 times.

Comparative Example 4

[0112] A lyocell tow for a cigarette filter was prepared in the same manner as in Example 1, except that the single fiber fineness was adjusted to 3.0 De, and the crimper draft ratio was adjusted to 1.1 times.

Experimental Example

[0113] Physical properties of the lyocell tows of the examples and comparative examples described above were measured according to the following method, and the results are shown in Table 1.

Method of Measuring Physical Property

(1) Measurement of Tow Fineness

[0114] A sample of the tow to be measured was collected in a size of 2 m and allowed to stand in a constant temperature and humidity room at 20? C. with a humidity of 65%. After fixing one end of the stabilized tow, the other end thereof was mounted with a 2 kg-weight. After stabilizing the tow elongated by the weight for 5 seconds, the sample was cut to a size of 90 cm and weighed. The fineness of the tow was converted into a measured weight?10000 value according to a denier conversion method.

(2) Measurement of Number of Crimps

[0115] According to the KS K 0326 standards, samples of 20 strands where crimps were not damaged were collected and each strand was added onto a previously prepared glossy paper sheet (spacing distance of 25 mm) with a celluloid 4 to 5% amyl acetate adhesive to be stretched by 25?5% relative to a length of a single strand, and then was left stand for drying the adhesive. The number of crimps of each sample was counted by applying a primary load of 1.96/1000 cN (=2 mgf) per 1 De to each strand using a crimp tester and the number of crimps in 25 mm was determined and averaged by excluding decimal places.

(3) Measurement of Shape of Crimp

[0116] A shape of crimps was visually identified using an optical microscope after sampling in the same manner as in the measurement of the number of crimps.

(4) Processibility of Cigarette Filter Manufacturing

[0117] Processibility of the cigarette filter manufacturing process was identified by evaluating processibilty maintainability until a sample of one batch was completely consumed after feeding the tow to a cigarette filter manufacturing facility.

(5) Measurement of Suction Resistance and Circumference of Cigarette Filter

[0118] Cigarette filter rods were prepared by using the tows prepared in the above-described examples and comparative examples, and suction resistance thereof was measured according to the KS H ISO 6565 standards and suction resistance of each rod was measured using a circumference measurer.

TABLE-US-00001 TABLE 1 Number Filter Filter Finness of crimps cigarette filter suction circum- of tow of tow Crimp Processibility resistance ference (De) (per inch) shape of manufacture (mmH.sub.2O) (mm) Example 1 36200 36~40 good good 446~454 24.22 (no breakage) Example 2 34500 30~34 good good 446~454 24.18 (no breakage) Example 3 39600 40~43 good good 446~454 24.24 (no breakage) Comparative impossible to impossible to Example 1 manufacture measure Comparative 37000 34~46 poor poor 375~420 24.52 Example 2 (impossible to continuously manufacture) Comparative 38400 32~50 poor poor 220~400 24.55 Example 3 (impossible to continuously manufacture) Comparative 45500 28~52 poor poor 200~380 24.58 Example 4 (impossible to continuously manufacture)

[0119] As shown in Table 1, in the case of Examples 1 to 3, the number of crimps was uniform according to the tow manufacturing conditions, and the tows manufactured by setting the conditions of the facility during manufacturing of cigarette filters had physical properties required for cigarette filters.

[0120] However, in the case of Comparative Example 1, conditions for manufacturing a tow were not appropriate, and thus tows could not be manufactured even by setting the conditions of the manufacturing process, and filter performance could not be identified.

[0121] In addition, although the tows were manufactured in the case of Comparative Examples 2 to 4, the tows were non-uniformly formed due to inappropriate manufacturing conditions.

[0122] That is, in Comparative Examples 1 to 3, the crimper draft ratio was out of the range of the present disclosure, so that it was impossible to manufacture the tow. Even when the tow was manufactured, the shape of crimps was poor, so that the cigarette filter was not able to be continuously manufactured, and accordingly suction resistance thereof was lower than those of the examples. In addition, in the case of spinning the spinning dope of Comparative Example 4, the filaments had a single fiber fineness of 3.0 De, which exceeded the range of the single fiber fineness of the filaments of the present disclosure, so that the fineness range of the tow exceeded 4000 De, and thus it was confirmed that processibility and physical properties of the cigarette filter thereof were inferior to those of Examples 1 to 3.

[0123] Therefore, it was confirmed that processibility was not maintained due to non-uniformity of the tow during manufacturing of the cigarette filter to which the tow manufactured according to the comparative examples, and it was difficult to realize filter performance due to non-uniformity of the tow.

[0124] On the contrary, in Example 1 to 3, the lyocell cigarette filter tow may have a fineness range of 25000 to 45000 De capable of realizing optimal cigarette filter performance by adjusting the crimper draft ratio in the crimping process. Therefore, according to the present disclosure, optimal processibilty for manufacturing a cigarette filter may be obtained by providing the lyocell tow having crimps capable of realizing physical properties of the cigarette filter equivalent to those of CA currently used in the art.