KR20160038800A - Crimped Lyocell Fiber - Google Patents

Abstract

The present invention relates to a crimped lyocell fiber manufactured by crimping a lyocell multifilament which is manufactured by spinning a lyocell spinning dope comprising cellulose pulp and an N-methylmorpholine-N-oxide (NMMO) aqueous solution. The crimped lyocell fiber has blooming index of 800 to 2,000.

Description

Crimped Lyocell Fiber < RTI ID = 0.0 >

The present invention relates to lyocell fibers, and more particularly to lyocell crimp fibers.

Fiber refers to a linear object with a very large fineness, ie, a ratio of length to thickness, which is flexible and thin when viewed in shape. Such fibers can be classified into long fibers, semi-long fibers and short fibers in terms of morphology, and natural fibers and man-made fibers in terms of raw materials.

Previously, fibers had a close relationship with human life. Early fibers were mainly used as raw materials for covering as natural fiber forms such as cotton, hemp, wool, and silk fibers. However, due to the development of science and technology since the Industrial Revolution, the use of fibers has expanded not only for covering materials but also for industrial use, and the field of artificial fibers has been newly opened to meet the rapidly increasing demands of culture and population.

In the case of man-made fibers, not only is the touch and feel comfortable with natural fibers, but also has excellent strength and quick moisture absorption and excretion function, it is steadily loved by people. Especially, in the case of regenerated fibers synthesized from natural materials such as wood pulp among synthetic fibers, it realizes almost the same tactile feeling as natural fibers, and is perceived to be harmless to the human body, so that interest in regenerated fibers is gradually increasing.

Among the regenerated fibers, viscose rayon has been widely used in the past as fibers having excellent glossiness and colorability comparable to silk. However, since viscose rayon has a somewhat complicated manufacturing process and many chemicals are used in the process of melting wood pulp and the like, there has been no controversy regarding environmental problems and wastewater treatment. Recycled fibers such as rayon-based regenerated fibers and cellulose acetate, which replace conventional viscose rayon fibers such as cupra-rayon and lyocell, have begun to stand out.

In particular, the lyocell fibers produced from natural pulp and amine oxide hydrates exhibit excellent tensile properties and feel compared to conventional regenerated fibers, and amine oxide-based solvents used in the production of lyocell fibers can be recycled and biodegradable The present inventors have not been able to generate any contaminants in the production process, and research on lyocell fibers has recently become more active as eco-friendly regenerated fibers.

Such a method of producing a lyocell fiber can be produced, for example, by spinning a spinning dope in which cellulose is dissolved in amine oxide (NMMO) as described in U.S. Patent Nos. 4,416,698 and 4,246,221, , Washing, drying, and processing. In addition, the lyocell fibers are not naturally crimped and can be useful for compressing the wet fibers according to the process described in European Patent No. 797,696, or using dry steam according to the process described in EP 703,997 Crimp can be imparted by stuffer box crimping.

However, in the case of conventional lyocell fibers, the bulgeability due to the formation of the crimp was not excellent. In addition, since research on most of the lyocell fibers has only been made to improve the physical properties such as strength improvement, technical researches that can effectively improve the lyophilicity of the lyocell fibers are steadily required.

Accordingly, it is desired to provide a lyocell crimped fiber having excellent crimp water and crimp stability and improved swelling characteristics through the present invention.

A preferred embodiment according to the present invention is a lyocell multifilament prepared by spinning a lyocell radial dope comprising an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO) Characterized in that the inflating index, defined by the following formula 1, is 800 to 2,000.

(Equation 1)

In this case, the expansion factor in the above equation (1) is defined by the following equation (2).

(Equation 2)

According to this embodiment, the lyocell spinning dope comprises 6 to 16% by weight of cellulose pulp based on the total spinning dope weight; And 84 to 94% by weight of an aqueous solution of N-methylmorpholine-N-oxide.

At this time, the cellulose pulp may have an alpha-cellulose content of 85 to 97% by weight based on the total weight of the pulp and a degree of polymerization (DPw) of 600 to 1700.

Also, according to the embodiment, the lyocell crimp fiber may have a crimp number (CN) per inch of 25 to 39 per inch and an inflation factor (BF) of 30 to 50 as defined by the formula 2.

According to this embodiment, the lyocell multifilament may be composed of a lyocell monofilament having a tensile strength of 2.0 to 3.5 g / d.

At this time, the lyocell monofilament may have a fineness of 1.0 to 8.0 denier and an elongation of 5 to 13%.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a lyocell crimp fiber having an improved swellability. The lyocell crimp fiber according to the present invention is excellent in the effect of improving the bulkiness and has excellent shape stability of the crimp. As a result, it is possible to expect a physical property equal to or higher than that of the conventional art even with a small amount of fibers when it is applied to clothing and industrial materials.

According to one aspect of the present invention, a lyocell multifilament prepared by spinning a lyocell radial dope comprising an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO) And has a swell index of 800 to 2,000 as defined by the following formula (1).

(Equation 1)

In this case, the expansion factor in the above equation (1) is defined by the following equation (2).

(Equation 2)

[Expansion factor and bulge index]

Generally, crimping refers to a process of imparting a crimp to a filament, which is also referred to as crimping. It is also referred to as crimping. In order to impart a natural fiber-like texture to a synthetic fiber produced by artificially spinning in the form of a fiber, . Since the crimped fibers have a space in which air can be present between the fiber bundles, a large volume can be formed even with the same weight, thereby ensuring a soft feeling and warmth. Further, the air permeability can be ensured and the antibacterial effect according to the ensuring of air permeability can be exhibited. Furthermore, if the fiber itself is an environmentally friendly biodegradable material like the lyocell of the present invention, the effect can be doubled.

Accordingly, the crimped lyocell fiber can be used as a textile material for winter clothes, quilts, medical fibers, hygienic materials including outdoor, innerwear, hats, sports socks and underwear, It can also be used for MRG (Mechanical Rubber Good) such as tire cord, various filters and hose reinforcement, cement reinforcements, automotive interior reinforcements and so on.

In the present invention, the inflating index defined by Equation 1 is a value determined by the inflation factor, which is the rate of change of the length of the crimp per inch formed in the lyocell fiber and the rate of change in length before and after permanent deformation, The larger the value, the greater the swelling factor or the number of crimps per inch. Accordingly, when the inflating index is less than 800, it is difficult to satisfactorily satisfy both the crimp count and the inflating factor, and the inflating index exceeds 2000, the technical Since the limit may exist, it is preferable that the inflation index satisfies the above range.

In order to satisfy such a bulge index range in the present invention, it is more preferable that the bulging factor defined as a percentage value of the width change ratio with respect to the fiber length change before and after the permanent deformation is in the range of 30 to 50 , And the crimp number (CN) measured per inch may preferably be 25 to 39 / inch.

As used herein, the term "permanent deformation" as used herein means a point in time when a crimped fiber is not pulled back and restored to its original shape when pulled and laid. In the present invention, Since the behavior of the permanent deformation at the load of. f is shown, the present invention can set the tensile at the load of 4 kgf as a reference for the permanent deformation.

If the crimped fiber is well formed, the number of crimps per inch is sufficient so that the fiber is well inflated by the crimp before the permanent deformation, but after the permanent deformation, the degree of swelling is significantly reduced, . On the other hand, if the crimp is not properly formed, there is not much difference in the degree of bulge caused by the crimp before and after the permanent deformation. As described above, the larger the bulging factor, the more the bulgeability can be interpreted as being excellent due to the sufficient crimping, and as a result, a satisfactory level of bulge index value can be obtained.

However, since the number of crimp per inch and inflation factor can not account for inversely conceptual behavior, the inflation factor may be greater than 30, considering the minimum number of crimps to be secured (25 / inch), and the number of crimps can be increased indefinitely It is difficult to exceed the swelling factor of 50 because there is not.

On the other hand, the lyocell crimped fiber of the present invention having the above-mentioned inflating characteristics can be manufactured through the steps (S1) to (S5).

[Step (S1)] [

(SI) step is a step of radiating a lyocell radial dope comprising an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO). According to a preferred embodiment of the present invention, the lyocell radial dope comprises 6 to 16% by weight of a cellulose pulse; And 84 to 94% by weight of an aqueous solution of N-methylmorpholine-N-oxide, wherein the cellulose pulp has an alpha-cellulose content of 85 to 97% by weight and a degree of polymerization (DPw) of 600 to 1700 have.

If the content of the cellulose pulp is less than 6% by weight, it is difficult to realize the fibrous shape and properties. If the content is more than 16% by weight, the cellulose pulp is difficult to dissolve in the aqueous solution and the tensile strength may be unnecessarily high. If the content of the aqueous solution of N-methylmorpholine-N-oxide is less than 84% by weight, the solubility of the resin is undesirably increased, and if it exceeds 94% by weight, the spinning viscosity is significantly lowered, It can be difficult.

Further, the step of discharging the spinning dope from the spinneret using the spinning dope may be performed at a spinning temperature of 80 to 130 캜. The spinneret serves to discharge the spinning dope on the filament as a coagulating solution in the coagulation bath through the air gap section. When the spinning temperature deviates from the spinning temperature, the flowability of the spinning dope is poor or the spinning dope viscosity is low, It can be difficult.

[Step S2]

(S2) is a step of solidifying the lyocell radial dope radiated in the step (S1) to obtain a lyocell multifilament, wherein the solidification in the step (S2) is performed by supplying quenching air to the radiation dope, (Air Quenching, Q / A); And a secondary coagulation step in which the primary coagulated radial dope is immersed in the coagulating liquid to coagulate.

After the spinning dope is discharged through the spinneret in the step (S1), it can be passed through the air gap section which is a space between the spinneret and the coagulation bath. In such an air gap section, cooling air is supplied from the inner air cooling portion located inside the detachment of the donut type to the outer side of the detachment, and primary coagulation can be achieved by air quenching which supplies the cooling air to the radiation dope.

In this case, the factor affecting the physical properties of the lyocell multifilament obtained in the step (S2) is the temperature and the wind speed of the cooling air in the air gap section, and the solidification in the step (S2) The cooling air having a wind speed of 50 m / s may be supplied to the spinning dope to solidify. If the temperature of the cooling air during the primary solidification is less than 4 ° C, the surface of the spinneret will cool down quickly, and the lyocell multifilament will also coagulate unevenly, resulting in poor spinning processability. If the temperature exceeds 15 ° C, This can also be adversely affecting the radiation fairness.

If the air velocity of the cooling air during the first solidification is less than 5 m / s, the primary coagulation due to the cooling air is not sufficiently carried out, resulting in poor yarn fairness and yarn splicing. If the air velocity exceeds 50 m / s, May be shaken by the air and radiation fairness may be reduced.

After primary coagulation by air quenching, the spinning dope is supplied to a coagulation bath containing the coagulation solution, and secondary coagulation can proceed. For proper secondary solidification, the temperature of the coagulating solution is preferably 30 DEG C or less, but the solidifying temperature can not be higher than necessary, so that the solidifying rate can be appropriately controlled. The coagulating solution is not particularly limited because it can be manufactured and used in a conventional composition in the technical field to which the present invention belongs.

[Step (S3)] [

(S3) is washing the lyocell multifilament obtained in the step (S2). Specifically, the lyocell multifilament obtained in the step (S2) may be introduced into a traction roller, introduced into a water bath, and then washed with water. In the washing step of the filament, a washing solution having a temperature of 0 to 100 ° C may be used in consideration of the ease of recovery and reuse of the solvent after washing with water. Water can be used as the washing solution, May be included.

[Step (S4)] [

(S4) is a step of tanning the lyocell multifilament washed in the step (S3), and it is preferable that drying after the tanning is performed. The tanning process can be carried out in such a way that the multifilament is completely submerged in the emulsion, and the jaws attached to the entry roll and the discharge roll of the tanning apparatus keep the amount of filaments touched by the emulsion by the rollers. The emulsion contributes to reducing the friction generated during the contact of the filament with the drying roller and the guide or crimping step, so that the crimp can be formed well.

According to a preferred embodiment of the present invention, the strength of the lyocell monofilament constituting the lyocell multifilament manufactured through steps (S1) to (S4) is preferably 2.0 g / d to 3.5 g / d. Herein, the monofilament refers to a single filament which is discharged from various filaments of a spinneret and separated from a fibrous multifilament after being subjected to a coagulation, washing and emulsion treatment step. The strength of the monofilament is determined by separating the fibrous multifilament It can mean the strength of an all-filament filament.

Generally, in the case of a fiber to which a crimp is imparted, the physical properties such as tactile feeling, bulkiness, warmth, and absorbency are often improved. Therefore, it is not necessary that the fiber has a minimum strength but an excessively strong strength. That is, if the strength of the lyocell monofilament is less than 2.0 g / d, the spinning processability may be deteriorated. If the lyocell monofilament is more than 3.5 g / d, not.

In addition, the lyocell monofilament preferably has a fineness of 1.0 to 8.0 deg in consideration of the swelling property. If the fineness of the monofilament is lower than 1.0de (denier), twisting phenomenon may occur between neighboring monofilaments upon crimping to increase the crimp number. If the monofilament fineness is higher than 8.0de, the crimp number is increased It is not desirable in terms of energy efficiency because the steam and pressure must be given more and the weight of the final product can be relatively increased even in the same inflow.

Further, the elongation of the lyocell monofilament may be 5 to 13%, and if the elongation is less than 5%, the fiber may easily be cut off during carding after crimp formation, and the yield may be lowered. It is not only difficult to control it to exceed 13%, but also it is not necessary to satisfy a superior elongation in consideration of the application field of the fiber which gives the crimp.

[Step (S5)] [

The step (S5) of the present invention is a step of crimping the lyocell multifilament treated in the step (S4). In the case of the lyocell crimp fiber of the present invention, the swellability can be determined in step (S5), and the crimp can be formed by applying steam to the lyocell multifilament and applying pressure thereto. The specific crimping means is a stuffer box, which may be a means including a steam box and a press roller.

Specifically, in the crimp method, it is preferable that the temperature of the filament is increased by passing the lyocell multifilament through a steam box and applying steam at 0.1 to 1.0 kgf / cm 2. At this time, if the supply amount of steam of the steam box is less than 0.1 kgf / cm 2, the shape can not be maintained because the press roller does not smoothly form the crimp or the crimp is formed, and if it exceeds 1.0 kgf / The temperature rises to 120 DEG C or higher, and the filaments stick together, so that they can not pass through the stopper box.

After passing through the steam box, the lyocell multifilament is supplied to a press roller and compressed at a pressure of 1.5 to 2.0 kgf / cm 2 to form a crimp. If the pressure applied to the press roller is less than 1.5 kgf / cm < 2 >, the desired crimp number is not formed. If the pressure is greater than 2.0 kgf / cm < 2 >, the pressing force is too strong and the filament may not pass through the stopper box.

In the present invention, the number of crimps formed while passing through the stopper box is very important, and the number of crimps is preferably 25 to 39 per inch / inch. When the number of crimps is less than 25 / inch, carding is not easy and the bulge factor defined by the above-mentioned formula 1 is less than 30, so that the bulging property in the width direction may be lowered, and even if the pressure of the press roller is increased, To be formed in excess of 39 / inch may be limited.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for the purpose of illustrating the present invention more specifically, and the present invention is not limited thereto.

Production Example 1

A cellulose pulp having a degree of polymerization (DPw) of 820 and an alpha-cellulose content of 93.9% was mixed with an NMMO / H20 mixed solvent (weight ratio 90/10) having a propylate content of 0.01% by weight to prepare a spinning dope for producing a lyocell fiber having a concentration of 12% Respectively.

First, the spinning dope was maintained at a spinning temperature of 110 ° C in a spinneret of the spinneret, and the discharge amount and spinning speed of the spinning dope were controlled to be 3.37 denier so that the filament had a fineness of 3.37 denier. The spinning dope on the filament discharged from the spinning nozzle was supplied to the coagulating solution in the coagulation bath through the air gap section. At this time, the cooling air in the air gap section is first coagulated with the spinning dope at a temperature of 8 캜 and a wind speed of 10 m / s.

The coagulating solution used was one with a temperature of 25 캜 and a concentration of 85% by weight of water and 15% by weight of NMMO. At this time, the concentration of the coagulating solution was continuously monitored using a sensor and an refractometer. The filament drawn in the air layer through the traction roller was washed with a wash water sprayed in a water washing device to remove the remaining NMMO and the filaments were allowed to uniformly adhere to the filament, and then squeezed again to give an emulsion content of 0.2 % And dried at 150 DEG C on a drying roller to prepare a lyocell filament.

The thus-prepared lyocell multifilament was passed through a stuffer box (press roller pressure: 1.5 kgf / cm 2), and a steam was not applied to the lyocell multifilament but the crimp was applied only by a press roller, Fiber.

The prepared lyocell crimped fiber was cut into a length of 200 mm in a tension free state, and then fixed at the first point (0 mm position) and the middle point (100 mm position), respectively. Then, a tensile force was applied at a distance of 200 mm to stretch the length to 50% (50 mm), and the end point was fixed at the extended position. The crimp number (CN) formed per 10 mm was obtained by dividing the tension by loosening the fixation at the point of 100 mm and taking a photograph of the microscope. The crimp number (CN) was calculated and converted into CPI (counts per inch) Was measured at 7 (ea / inch).

Manufacturing example  2 to 6

The lyocell crimp fiber was prepared by applying the same method as in Preparation Example 1 except that the number of crimps was 15 (ea / inch), 20 (ea / inch), 25 (ea / inch, 30 (ea / inch) and 39 (ea / inch), respectively. However, even when the press roller pressure was changed, the number of crimps was not increased any more, and thus, the manufacturing example was limited to the case that the crimp number was 39 ea / inch.

Examples 1 to 3

The same procedure as in Preparation Example 4 (1) was repeated except that steam was applied to the steam box at a pressure of 1.0 kgf / cm 2 (120 ° C) in order to heat-set the lyocell fibers in the stuffer box before passing them through the press roller. (Examples 1 to 3) having crimp numbers of 25 (ea / inch), 30 (ea / inch) and 39 (ea / inch) were respectively applied.

Comparative Examples 1 to 3

The cuff counts were 7 (ea / inch), 15 (ea / inch), and 15 (ea / inch), respectively, by applying the same method as Production Examples 1 to 3 except that steam treatment was performed in the stuffer box as in Examples 1 to 3 20 (ea / inch). Comparative Examples 1 to 3 were prepared.

Measurement example

All of the above Production Examples 1 to 6, Examples 1 to 3 and Comparative Examples 1 to 3 were allowed to stand under the conditions of constant temperature and humidity (temperature: 22 ° C, humidity: 55%) for 48 hours and then subjected to UTM (Universal Testing Machine, 5566, test mode: Tension test). As a result of the tensile strength test, when the load was 4 kgf, the permanent deformation of the crimped fiber began to appear. The length (I.length) and the width (I.width) of the sample before the tensile strength test and the sample The length (A.length) and the width (A.width) of the resin were substituted into the following equation (1) to calculate the Blooming Factor (BF).

Equation 1)

Change of fiber length before and after permanent deformation: ΔL = | (A.length) - (I.length) |

Variation of fiber width before and after permanent deformation: ΔW = | (A.width) - (I.width) |

In addition, as shown in the following equation 2, the embossing index is obtained by multiplying the crimp number of each of Examples 1 to 2 and Comparative Examples 1 and 2 by the measured swollen factor, and the values are reflected in Table 1 below.

Equation 2)

Sample Heat fix treatment
The presence or absence Cr. No.
(CN) ? L ¹⁾ ΔW ²⁾ Blooming
Factor Bulge
Indices
(BFxCN) Production Example 1 X 7 80 4 5.0 35.0 Production Example 2 X 15 77 5 6.5 97.5 Production Example 3 X 20 76 7 9.2 184.0 Production Example 4 X 25 70 10 14.3 357.5 Production Example 5 X 30 68 10 14.7 441.0 Production Example 6 X 39 65 10 15.4 600.6 Comparative Example 1 O 7 78 4 5.1 35.7 Comparative Example 2 O 15 73 5 6.8 102.0 Comparative Example 3 O 20 65 7 10.7 214.0 Example 1 O 25 62 22 35.4 885.0 Example 2 O 30 60 24 40.0 1,200.0 Example 3 O 39 58 27 46.5 1,813.5

1) ΔL: length of fiber before and after permanent deformation

2) ΔW: Width change of fiber before and after permanent deformation

As can be seen from Table 1, when the results of the bulge factor and the bulge index are compared, when the number of crimps per inch is 25 or more, the bulge factor and the index increase remarkably. Especially, when the bulge index is 800 , And thus it was confirmed that the lyocell crimp fiber had a very good swellability.

In particular, even if the number of crimp is more than 25, the inflation factor does not reach 30 and the inflation index does not increase any further. If the crimp number is less than 25, the inflation factor and inflation index are both high It is difficult to secure.

Claims (7)

Cellulose multifilament prepared by spinning a lyocell radial dope containing an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO)
Characterized in that the swelling index defined by the following formula 1 is 800 to 2,000;
(Equation 1)

In this case, the expansion factor in the formula (1) is defined by the following formula (2).
(Equation 2)

The method of claim 1, wherein the lyocell spinning dope comprises 6 to 16% by weight of a cellulose pulp based on the total weight of the spinning dope; And 84-94 wt% aqueous solution of N-methylmorpholine-N-oxide.
The lyocell crimped fiber according to claim 2, wherein the cellulose pulp has an alpha-cellulose content of 85 to 97% by weight based on the total weight of the pulp, and a polymerization degree (DPw) of 600 to 1,700.
The lyocell crimped fiber according to claim 1, wherein the lyocell crimp fiber has a crimp count per inch of from 25 to 39 per inch and a swelling factor of from 30 to 50 as defined by the formula 2.
The lyocell crimped fiber of claim 1, wherein the lyocell multifilament comprises a lyocell monofilament having a tensile strength of 2.0 to 3.5 g / d.
6. The lyocell crimp fiber according to claim 5, wherein the lyocell monofilament has a fineness of 1.0 to 8.0 denier.
6. The lyocell crimped fiber of claim 5, wherein the lyocell monofilament has an elongation of 5-13%.