KR20150113902A - Lyocell Fiber - Google Patents

Abstract

The present invention relates to a lyocell fiber and, more specifically to a lyocell fiber capable of showing physical properties to a level equal to or higher than a conventional lyocell fiber, even if a little amount is used, by increasing a specific surface of the fiber by controlling a cross sectional shape of a monofilament included in the lyocell fiber.

Description

Lyocell fiber {Lyocell Fiber}

The present invention relates to lyocell fibers.

Fiber means a natural or artificial linear object that is flexible and thin when viewed in shape and has a large length to thickness ratio. These fibers are divided into long fibers, quasi-long fibers, and short fibers. The fibers are divided into natural fibers and man-made fibers.

Previously, fibers had a close relationship with human life, and natural fibers such as cotton, hemp, wool, and silk fiber were used as the main raw materials for the fabrics. Since the industrial revolution, the textile has expanded its application not only to the covering materials but also to the industrial use. In order to meet the rapidly increasing demand of the fiber with the development of the culture and the population, It was pioneered.

Among these man-made fibers, regenerated fibers are not only excellent in feel and fit, but also have moisture absorbing and discharging ability much faster than cotton, and thus they have been widely used as raw materials for coating. Particularly, among these regenerated fibers, rayon fibers have excellent gloss and coloring property and can not only realize a feeling equivalent to that of natural fibers but also have been widely used in the past as they are recognized as harmless materials to human body. However, these rayon fibers have characteristics of shrinkage and creasing. Since the manufacturing process is complicated and a lot of chemicals are used in the process of melting wood pulp and the like, environmental pollution And the like.

As a result, research has been conducted on fibers that are harmless to the environment and human body and have superior physical properties and superior to other conventional fibers. Recently, Lyocell fibers produced from natural pulp and amine oxide hydrates have been introduced. These lyocell fibers have excellent tensile properties and tactile properties as compared with conventional regenerated fibers, and do not generate any contaminants in the production process. The amine oxide-based solvent used is recyclable and biodegradable upon disposal , And are used in various fields as environmentally friendly fibers.

However, at present, it is expected that the lyocell fiber can be produced only in the form of a circular cross-section, and it is expected that it can exhibit various physical properties depending on the cross-sectional shape of the lyocell fiber. Research is required.

The present invention aims to provide a lyocell fiber having a large specific surface area.

Accordingly, the present invention provides, as a first preferred embodiment, a method of producing a lyocell multi-cell lyophilized product prepared by spinning a lyocell radial dope containing an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO) Filaments comprising monofilaments whose cross-section is an unmodified cross-section, the modified cross-section comprising a plurality of projections, the plurality of projections comprising a virtual first circle and a virtual first circle Wherein the virtual second circle is in contact with the imaginary second circle included in the virtual circle and has a shape that is integrally formed with the imaginary second circle as a central portion and has a shape in which its end is in contact with the imaginary first circle do.

The lyocell spinning dope according to this embodiment may comprise 6 to 16% by weight of cellulose pulp; And 84 to 94% by weight of an aqueous solution of N-methylmorpholine-N-oxide.

The cellulose pulp according to the embodiment may have an alpha-cellulose content of 85 to 97% by weight and a degree of polymerization (DPw) of 600 to 1700.

The lyocell fiber according to the embodiment may have a space occupancy of 150 to 400% defined by the following formula (1).

<Formula 1>

Space occupancy (%) = (area of imaginary first circle / cross-sectional area of monofilament contained in lyocell fiber) x 100

The imaginary first circle according to the embodiment may have a radius of 8 to 30 占 퐉.

The imaginary second circle according to the embodiment may have a radius of 3 to 12 占 퐉.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a large lyocell fiber having a specific surface area and, when it is used in a garment, a building material or an automobile reinforcing material, it can exhibit physical properties equal to or higher than those of conventional lyocell fibers It is effective.

FIG. 1 is a schematic cross-sectional view of a monofilament included in a lyocell fiber according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a lyocell fiber fabricated according to an embodiment of the present invention. FIG. 2 (a) Fig. 3 is a cross-sectional photograph of the lyocell fiber obtained in Example 1;

Hereinafter, the present invention will be described in more detail.

The present invention relates to a lyocell multifilament prepared by spinning a lyocell radial dope comprising an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO), wherein the multifilament Wherein the plurality of protrusions comprises a virtual first circle and a virtual second circle included in the virtual first circle and the virtual second circle includes a plurality of protrusions, And the lyocell fiber is integrally formed with the circular second circle as a central portion, and has a shape in which the distal end thereof is in contact with the imaginary first circle.

[Multi lobal]

In the present invention, the modified cross section means a shape including a plurality of protrusions. Specifically, as shown in FIG. 1, the modified cross section means a cross section having a plurality of projections formed integrally with one central portion 1 as a center.

Specifically, the modified cross section includes a virtual first circle 11 connecting the end points of each of the plurality of projections, and a virtual second circle 12 included within the virtual first circle 11, Can define its size and shape. The imaginary first circle 11 and the imaginary second circle 12 are arranged such that the imaginary first circle 11 has a larger radius than the virtual second circle 12, May have the same center but may not have the same center.

And a plurality of protrusions are formed integrally with the central portion 1 overlapping with the imaginary second circle 12, and the ends 5 of each of the protrusions are formed by the virtual And the concave portion 4 formed between the projections is in contact with the imaginary second circle 12.

In the present invention, in terms of maximizing the specific surface area of the lyocell fiber, the modified cross section may include three protrusions.

The virtual first circle may have a radius of 8 to 30 占 퐉 and the imaginary second circle may have a radius of 3 to 12 占 퐉.

If the radius of the imaginary first circle is 8 탆 or more, a monolithic cross-sectional shape can be realized. If the radius is 30 탆 or less, a monofilament having a fineness suitable for a fiber product can be formed. If the radius of the imaginary second circle is 3 탆 or more, a monolithic cross-sectional shape can be realized. If the radius is 12 탆 or less, a monofilament having a fineness suitable for a fiber product can be formed.

The monofilament included in the lyocell fiber according to the present invention has a modified cross-section as described above, and the lyocell fiber may have a space occupancy of 150 to 400% defined by Equation 1 below.

<Formula 1>

Space occupancy (%) = (area of imaginary first circle / cross-sectional area of monofilament contained in lyocell fiber) x 100

Here, the space occupancy means the ratio of the space in which the monofilaments are substantially occupied in the fibers due to the protrusions of the mold section. That is, when the cross section of the monofilament included in the lyocell fiber is a circular cross-section, since the cross-sectional area of the actual monofilament is equal to the area of the imaginary first circle, the space occupancy defined above is 100% In the case of fibers having a deformed cross section, the actual area occupied by the fibers is increased by the projections. Therefore, as the space occupancy increases, the specific surface area of the fibers increases.

The lyocell fiber of the present invention has a space occupancy of 150 to 400%, preferably 300 to 400, as defined in the above formula 1, in terms of improving various properties such as swelling property, interfacial adhesion property, %.

The present invention also provides a method for producing a lyocell radial dope comprising the steps of: (S1) spinning a lyocell radial dope comprising an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO); (S2) solidifying the lyocell radiation dope radiated in the step (S1) to obtain a lyocell multifilament; (S3) washing the lyocell multifilament obtained in the step (S2); And (S4) emulsion-treating the lyocell multifilament washed in the step (S3), wherein the multifilament is made of monofilaments whose cross-section is an aliphatic cross-section, Wherein the deforming cross-section includes a plurality of protrusions, wherein the plurality of protrusions contact a virtual first circle and a virtual second circle contained within the virtual first circle, And having a shape in which the distal end thereof is in contact with the imaginary first circle.

[Step (S1)] [

(S1) is a step of radiating a lyocell spinning dope containing an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO).

The lyocell spinning dope comprises 6 to 16% by weight of cellulose pulp; 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 in the lyocell radial dope is less than 6% by weight, it is difficult to realize the fiber property. If the content is more than 16% by weight, it may be difficult to dissolve in the aqueous liquid.

If the content of the aqueous solution of N-methylmorpholine-N-oxide in the lyocell radial dope is less than 84% by weight, the solubility of the solution is undesirably large, and if it exceeds 94% by weight, It may be difficult to produce a uniform fiber.

The weight ratio of N-methylmorpholine-N-oxide and water in the N-methylmorpholine-N-oxide aqueous solution may be 93: 7 to 85:15. When the weight ratio of N-methylmorpholine-N-oxide and water is more than 93: 7, the dissolution temperature is high and the cellulose may be decomposed upon dissolving cellulose. When the weight ratio is less than 85:15, And the dissolution of cellulose may be difficult.

The above-described radiation dope is used to discharge it from the spinneret of the spinneret. At this time, the spinneret serves to discharge the spinning dope on the filament as a coagulating solution in the coagulation bath through the air gap section. The step of discharging the spinning dope from the spinneret can be performed at a spinning temperature of 80 to 130 캜.

The spinneret may be a spinneret having a plurality of unit holes formed when a plurality of holes are set as one unit hole in the shape of the spinneret. At this time, the number of the plurality of holes included in the unit hole may be the same as the number of the protrusions of the deforming section. For example, in order to produce a lyocell fiber including monofilaments having a modified cross section including three projections, the number of holes included in the unit holes may be three.

[Step S2]

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

In the step (S1), after the spinning dope is discharged through the spinneret, it can be passed through the air gap section of the space between the spinneret and the coagulation bath. In such an air gap section, cooling air is supplied from the air cooling part located inside the detachment of the donut type to the outside from the inside of the detent, which can be primary solidified by air quenching which supplies the cooling air to the radiation dope.

At this time, 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 캜, the surface of the spinneret cools, the cross-section of the lyocell multifilament becomes uneven and the spinning processability becomes poor. If the temperature is more than 15 캜, The radiation fairness becomes poor.

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 insufficient and the spinning durability is poor and the spinning dope is generated. If the air velocity exceeds 50 m / s, It is shaken by the air and the radiation fairness becomes poor.

After primary coagulation by air quenching, the spinning dope is supplied to the coagulation bath containing the coagulation solution and secondary coagulation can proceed. On the other hand, the temperature of the coagulating solution may be 30 DEG C or less for the progress of proper secondary coagulation. This is so that the secondary solidification temperature is not higher than necessary, so that the solidification rate is properly maintained. Herein, the coagulating solution is not particularly limited as 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 and then introduced into a water bath to be washed with water.

In the washing step of the filament, a washing solution at 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 further included.

[Step (S4)] [

(S4) is a step of tanning the lyocell multifilament washed in the step (S3), and may be dried after emulsion treatment.

The emulsion treatment takes the form that the multifilament is buried in the emulsion completely, and the amount of the emulsion adhered to the filament by the rollers on the entrance roll of the emulsion treatment apparatus and the discharge roll is kept constant. The emulsion serves to reduce the friction generated when the filaments contact with the drying roller, the guide, and the crimping step.

The lyocell fiber as described above is biodegradable and therefore environmentally friendly.

In addition, the lyocell fiber shows a shape of a modified cross section in which the monofilament includes a large number of projections. The lyocell fiber exhibits a property equivalent to or higher than that of a conventional circular cross-section lyocell fiber even if a small amount is used. Can be manufactured.

Particularly, since the lyocell fiber according to the present invention has a large non-target area, when used in a garment, a building, or a reinforcing material for an automobile field, it has an effect of exhibiting physical properties equal to or higher than those of conventional lyocell fibers have.

When the lyocell fiber according to the present invention is used for clothing, it exhibits excellent moisture-absorbing and quick-drying property due to its large specific surface area, so that even when sweat is discharged, there is no wrapping around the body and the skin is always kept in a pleasant state, have. Furthermore, since the cooling speed is excellent, rapid cooling can be maintained when sweat is continuously discharged. Specifically, the range of application for clothing may include outdoor wear, sports wear, T-shirts, golf wear, men's and women's wear, functional innerwear, hats, sports socks and undergarments.

When the lyocell fiber according to the present invention is used as a reinforcing material, the larger the contact area with the material to be reinforced, the greater the reinforcing function. It is applicable to MRG (mechanical rubber good) such as tire cord and hose reinforcement, cement reinforcement material, .

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for describing the present invention in more detail and that the scope of the present invention is not limited by these embodiments.

Example 1

Degree of polymerization (DPw) 820, an alpha cellulose content of 93.9% were mixed in a cellulose content of 0.01% by weight of propyl gallate NMMO / H ₂ 0 mixture solvent (weight ratio 90/10) pulp, lyocell fiber spinning for producing a concentration of 12% by weight Dope.

First, the spinning dope was maintained at a spinning temperature of 110 ° C in a spinneret of a spinneret having a plurality of unit holes including three holes. The discharge amount and the spinning speed of the spinning dope were adjusted so that the fineness of the filament was 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 filaments and then squeezed again so that the filament had an emulsion content of 0.2 % And dried at 150 ° C on a drying roller to prepare a lyocell fiber including multifilaments composed of monofilaments having a modified cross section including three projections.

Example 2

A lyocell fiber including a multifilament composed of monofilaments having a modified cross section including three protrusions was prepared in the same manner as in Example 1 except that the filament had a fineness of 3.58 denier.

Example 3

A lyocell fiber including a multifilament composed of monofilaments having a modified cross section including three projections was prepared in the same manner as in Example 1 except that the filament had a fineness of 14.82 denier.

Comparative Example 1

A monofilament having a circular cross section was prepared in the same manner as in Example 1, except that one circular hole was used as a unit hole, and a spinneret having a plurality of unit holes was used and the fineness of the filament was 1.73 denier Lt; RTI ID = 0.0 &gt; of &lt; / RTI &gt; multifilament.

Comparative Example 2

A lyocell fiber including a multifilament composed of a monofilament having a circular cross section was prepared in the same manner as in Comparative Example 1, except that the filament had a fineness of 2.97 denier.

The cross-sectional shape, fineness and space occupancy of the monofilaments contained in the lyocell fibers prepared in Examples and Comparative Examples were measured and calculated in the following manner. The results are shown in Table 1 below .

(1) Cross-sectional shape of the monofilament contained in the lyocell fiber

A small amount of fiber bundle was sampled and cut with a black cotton pad to make it thin. The cut was inserted into the hole of the plate, and cut with a razor blade so that the cross section was not pushed.

The images were enlarged (× 200) using an optical microscope (BX51, Olympus) and images were recorded with a digital camera. Cross-sectional images of the fibers were determined using the Olympus soft imaging solution program and the radius and area were analyzed.

(2) Fineness

The fineness of the lyocell fiber was calculated by the following formula 2 using the cross-sectional area of the monofilament of the actual lyocell fiber obtained from the cross-sectional analysis and the density of the lyocell fiber.

Density of lyocell fiber = 1.49 g / cm &lt; ³ &gt;

<Formula 2>

Fineness (De) = [density of the lyocell monofilament cross-sectional area of the fiber (㎛ ²⁾ × lyocell fiber ^{(g / cm 3) × 9000} (m)] / 1000000

(3) Space occupancy

The space occupancy of the lyocell fibers was calculated by the following formula (1).

<Formula 1>

Space occupancy (%) = (area of imaginary first circle / cross-sectional area of monofilament contained in lyocell fiber) x 100

The cross-sectional shape of the monofilaments contained in the lyocell fiber
Fineness
(De)

L1 / L2
space
Share
(%) A virtual first circle
radius
(L1, 占 퐉)
A virtual second circle
radius
(L2, 占 퐉)
A virtual first circle
Area (㎛ ² )
Actual cross-sectional area of the monofilament of the Lyocell fibers (탆 ² ) Example 1 16.75 3.87 881 251.6 3.37 4.33 350 Example 2 11.44 6.16 411 266.6 3.58 1.86 154 Example 3 27.78 11.61 2423 1105 14.82 2.40 219 Comparative Example 1 6.4 6.4 129 129 1.73 One 100 Comparative Example 2 8.4 8.4 222 222 2.97 One 100

As shown in Table 1, the lyocell fibers of Examples 1 to 3 made of monofilaments having a modified cross-section had a smaller space occupancy rate than the lyocell fibers of Comparative Example 1 and Comparative Example 2, which were composed of monofilaments having a circular cross- . Here, the cross-sections of the lyocell fibers of Examples 1 to 3 are as shown in Figs. 2 (a) to 2 (c), respectively.

From these results, it can be seen that the lyocell fibers of Examples 1 to 3 have a large specific surface area, and that they can be widely applied to fields requiring a fiber having a large specific surface area.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereto will be. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

1: center portion, 2: projection, 3: long axis of projection, 4: concave portion of projection, 5: end of projection
11: virtual first circle, 12: virtual second circle

Claims (7)

Cell multifilament prepared by spinning a lyocell radial dope comprising an aqueous solution of cellulose pulp and N-methylmorpholine-N-oxide (NMMO)
Wherein the multifilament is composed of monofilaments whose cross section is an irregular cross section,
Wherein the modified cross-section includes a plurality of projections,
Wherein the plurality of protrusions are formed integrally with the imaginary first circle and the imaginary second circle included in the imaginary first circle, with the imaginary second circle as a central portion, Of the lyocell fibers are in contact with the first circle of the lyocell fiber.
The method according to claim 1,
The lyocell spinning dope comprises 6 to 16% by weight of cellulose pulp; And 84-94 wt% aqueous solution of N-methylmorpholine-N-oxide.
3. The method of claim 2,
Wherein the cellulose pulp has an alpha-cellulose content of 85 to 97% by weight and a degree of polymerization (DPw) of 600 to 1,700.
The method according to claim 1,
Wherein the lyocell fiber has a space occupancy of 150 to 400% defined by the following formula 1:
<Formula 1>
Space occupancy (%) = (area of imaginary first circle / cross-sectional area of monofilament contained in lyocell fiber) x 100
The method according to claim 1,
Wherein the virtual first circle has a radius of 8 to 30 占 퐉.
The method according to claim 1,
Wherein the imaginary second circle has a radius of from 3 to 12 占 퐉.
The method according to claim 1,
Wherein the imaginary first circle and the imaginary second circle have the same center.

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