KR20180077801A - Lyocell Fiber - Google Patents

Abstract

The present invention relates to a lyocell fiber, and more specifically, to a lyocell fiber which is a flat yarn having a flat cross section of monofilaments by controlling the cross-sectional shape of the monofilaments contained in the lyocell fiber, or is a flat yarn having curvature. The lyocell fiber of the present invention has excellent bending properties and good texture to be applied to clothes and interior products.

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

It is an object of the present invention to provide a lyocell fiber in which the cross section of the monofilament is flat or has a curvature, thereby providing a lyocell fiber having excellent curvature characteristics for industrial material use, good texture and soft gloss for clothing or interior use, , Skin adhesion, solvent absorbency and retention such as moisture, smooth surface touch, and the like.

The monofilament constituting the multifilament has a cross-section of a center long axis (L1) and a center long axis (L1). The monofilament is formed by spinning a lyocell radial dope containing a cellulose pulp and a solvent. Wherein a ratio of a length of the center major axis (L1) to a center minor axis (S1) is 3.0 to 6.0: 1 and a ratio of a length of the center long axis (L1) L2) length of the lyocell is 1.0 to 1.5: 1.

In this embodiment, the length of the center long axis L1 of the monofilament may be 12 to 42 mu m, and the length of the center short axis S1 may be 4 to 7 mu m.

In the above-described embodiment, the monofilament may have a fineness of 1.0 to 4.0 denier and a value obtained by dividing the peripheral length of the monofilament by the fineness of 22 mu m / denier or more.

INDUSTRIAL APPLICABILITY The present invention can exhibit physical characteristics that can not be provided by conventional circular cross-sectioned lyocell fibers by providing a lyocell fiber in which the cross section of monofilaments is flat or has a curvature, It has become possible to provide an effect having excellent physical properties such as bending property, good feel and soft gloss property for clothing or interior use, and solvent absorption property and water retention property such as transparency, skin adhesion, moisture and smooth surface tackiness for use in a mask pack nonwoven fabric.

FIG. 1 is a schematic cross-sectional view of a monofilament included in a lyocell fiber according to an embodiment of the present invention.
2 is a photograph showing a cross section of a lyocell fiber produced according to an embodiment of the present invention.

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 a cellulose pulp and a solvent, wherein the monofilament constituting the multifilament has a cross section having a center long axis (L1) and a center short axis (S1) Wherein a ratio of a length of the center long axis L1 to a center short axis S1 is 3.0 to 6.0: 1 and a ratio of a length of the center long axis L1 to a length of a straight line L2 at both ends of the center long axis 1.0 to 1.5: 1.

The lyocell fiber of the present invention comprises a monofilament having a flat cross section, the cross section of which is shown in Fig.

That is, the length of the center long axis L1 is at least three times longer than the length of the center short axis S1, and is at most six times less than the length of the center short axis S1, so that the cross section becomes flat with a flat shape. And the length of the straight line L2 at both ends of the central longitudinal axis is 1: 1, the straight line becomes a straight line. If the ratio exceeds 1: 1, the straight line having a curvature becomes a flat line will be.

As described above, since the cross section of the monofilament is flat or curved and flattened, it is possible to exhibit the physical characteristics that the conventional circular cross-section of the lyocell fiber could not exhibit. In particular, excellent bending It is possible to exhibit excellent physical properties such as a good feel and smooth gloss property for a clothing, an interior use, and a mask pack nonwoven fabric, such as transparency, skin adhesion, solvent absorbency and retention, and smooth surface touch.

The length ratio between the center major axis L1 and the center minor axis S1 should satisfy the range of 3.0 to 6.0: 1, with the center major axis L1 and the center minor axis S1, It is difficult to exhibit properties significantly different from those of the circular cross section yarns. When the ratio exceeds 6.0: 1, the desired fineness of the final fiber can not be attained.

The ratio of the length of the central longitudinal axis (L1) to the length of the straight line (L2) at both ends of the central longitudinal axis is 1.0 to 1.5: 1. When the ratio of the curvature exceeds 1.5: 1, The effect of the flat yarn is reduced because the interfiber adhesion is lowered.

The monofilament of the present invention is characterized in that the length of the center long axis L1 is 12 to 42 mu m and the length of the center short axis S1 is 4 to 7 mu m, The range of fiber production is within the fineness range of 1.0 to 4.0 denier.

That is, the length of the center short axis of less than 4 탆 is difficult to realize due to the limitations of the cage manufacturing processing technology, and the fineness of the central long axis must be larger than 42 탆.

The monofilament of the present invention has a fineness of 1.0 to 4.0 denier and a value obtained by dividing the end face circumferential length of the monofilament by the fineness of 22 mu m per denier or more, When applied to a product, can be applied to an effective field. For example, the mask pack nonwoven fabric can have an advantage of excellent absorbency and retention of essence.

As described above, the lyocell fibers as described above are biodegradable, and thus environmentally friendly. Further, the lyocell fibers of the present invention show a monofilament having a straight flat cross section or a curved flat cross section, Compared to the cross section, the bending property to withstand the external force becomes strong, and the fiber strand becomes a mirror-like mirror-like reflection, so that the surface is shiny and shiny. In addition, the tactile feeling can be applied to various fields such as a car seat cover, a car seat cover, a carpet, a curtain, various industrial materials such as a garment, and a garment use, because of a special section effect.

In particular, when the lyocell fiber according to the present invention is produced in the form of staple fiber and used in a mask pack nonwoven fabric sheet, the most important property of the mask pack nonwoven fabric is transparency, skin adhesion, essence absorbency and retention, It has an effect of exhibiting very excellent physical properties.

When the fiber cross-section is flat, the thickness of the fiber becomes small, and when the nonwoven fabric is manufactured, the thickness of the nonwoven fabric becomes thinner than that of a general circular cross-section fiber at the same unit weight. Therefore, when dipped in a cosmetic solvent such as essence, .

In addition, since the specific surface area is larger than that of the circular cross-section fibers having the same fineness, the absorbency to solvents such as essence is high, and the essence holding power is also excellent, which is a great advantage compared to other materials applied to the mask pack nonwoven fabric.

The present invention relates to (S1) radiating a lyocell radial dope comprising a cellulose pulp and a solvent; (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) a step of emulsifying the lyocell multifilament washed in the step (S3), wherein the monofilament constituting the multifilament has a cross section of the center long axis L1, Wherein a ratio of a length of the center major axis (L1) to a center minor axis (S1) is 3.0 to 6.0: 1 and a ratio of a length of the center long axis (L1) L2) is 1.0 to 1.5: 1 in terms of the length of the lyocell fiber.

The lyocell fiber of the present invention can be prepared by dissolving a cellulose pulp in a solvent to prepare a lyocell spinning dope and then spinning the spinning dope to prepare a lyocell fiber. (NMMO) aqueous solution or an ionic solvent. Hereinafter, a method for producing the lyocell fiber of the present invention using an aqueous solution of NMMO Will be described in detail.

[Step (S1)] [

(S1) is a step of radiating a lyocell spinning dope comprising cellulose pulp and an NMMO aqueous solution.

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 spinneret may have a slit-shaped hole formed in a long and flat shape with a cantilever shape bent in a C-shape.

It is also important that the arresting of detention holes be very important and that all holes may be in contact with the cooling air during air quenching and should not interfere with each other.

The step of discharging the spinning dope from the spinneret can be performed at a spinning temperature of 80 to 130 캜.

[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 10 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.

In addition, the flat yarn is very sensitive to the air quenching velocity during spinning. 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 sufficient, If it is more than 10m / s, the radial dope discharged from the cage is flattened, so that the length of the center short axis is shortened, and it is shaken by air quenching,

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 tanning process takes the form that the multifilament is buried as it passes over the surface of the roller bearing the tanning agent and adjusts the amount of tanning agent applied to the filament by the speed of the tanning roller. The tanning agent serves to reduce the friction generated when the filaments come into contact with the drying roller and the guide, the winding or the crimping step.

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

A cellulose pulp having a degree of polymerization (DPw) of 820 and an alpha-cellulose content of 93.9% was mixed with an NMMO / H ₂ O mixed solvent (weight ratio 90/10) having a propyl gallate content of 0.01% by weight to prepare a lyocell fiber Dope.

First, the spinning dope was maintained at a spinning temperature of 110 캜 in a spinneret of a spinneret having a plurality of flat slit-shaped unit holes having a curvature, and the discharge amount of the spinning dope was adjusted to be 2.0 denier The emission rate was adjusted to emit. 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 firstly solidified by spinning dope at a temperature of 8 캜 and a wind speed of 7 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 filaments drawn in the air layer through the traction roller were washed with a wash water sprayed in a water washing device to remove the remaining NMMO and the emulsion was uniformly applied to the filaments so that the emulsion content was maintained at 0.2% And dried at 150 캜 to prepare a lyocell fiber including multifilaments composed of monofilaments having a curvilinear flat section.

Example 2

A lyocell fiber including a multifilament made of a monofilament having a curvilinear flat section was prepared in the same manner as in Example 1, except that the monofilament had a fineness of 1.66 denier.

Example 3

A lyocell fiber including a multifilament made of a monofilament having a curved flattened cross section was prepared in the same manner as in Example 1, except that the monofilament had a fineness of 2.39 denier.

Comparative Example 1

The same procedure as in Example 1 was carried out except that one circular hole was used as a unit hole and a spinneret having a plurality of unit holes was used and the air quenching air velocity was 15 m / To prepare a lyocell fiber comprising multifilaments composed of monofilaments having a circular cross section with a cross-section diameter of 13.78 mu m.

Comparative Example 2

A lyocell fiber including a multifilament composed of monofilaments having a circular cross section with a diameter of 15.06 mu m was produced in the same manner as in Comparative Example 1, except that the monofilament had a fineness of 2.39 denier.

The cross-sectional shapes, cross-sectional areas, fineness and fiber thickness of the monofilaments contained in the lyocell fibers were measured and calculated for the lyocell fibers prepared in the Examples and Comparative Examples as follows, Respectively.

(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 (× 500) using an optical microscope (BX51, Olympus), and images were stored with a digital camera. The cross-sectional images of the fibers were analyzed using the Olympus soft imaging solution program and the lengths and areas of the major and minor axes, the fiber thicknesses, and the circumferential lengths were analyzed.

(2) Fineness

The monofilament cross-sectional area of the actual lyocell fibers obtained from the cross-sectional analysis and the density of the lyocell fibers (1.49 g / cm ³ ) were calculated to calculate the fineness of the lyocell fibers.

<Formula 1>

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

Sectional shape of the monofilament
Fineness
(De)
(占 퐉) / Fineness (De) L1 / S1 L1 / L2 Remarks Center long axis length
(L1, 占 퐉)
Center short axis length
(S1, 占 퐉)
Connection length of center long axis end
(L2, 占 퐉)
Circumferential length
(탆) Actual cross-sectional area of the monofilament of the Lyocell fibers (탆 ² ) Example 1 23.89 5.98 19.84 61.02 148.94 2.0 30.5 4.0 1.2 Flat cross section Example 2 20.28 5.89 18.21 53.81 124.11 1.66 32.4 3.4 1.1 Flat cross section Example 3 29.05 6.20 21.06 69.75 178.42 2.39 29.2 4.7 1.4 Flat cross section Comparative Example 1 Circular cross-section diameter: 13.78 43.26 149.00 2.0 21.6 Circular section Comparative Example 2 Circular cross section diameter: 15.06 47.35 178.00 2.39 19.8 Circular section

As shown in Table 1, the lyocell fibers of Examples 1 to 3 made of monofilaments having a flattened cross-section with a curvature were made from the lyocell fibers of Comparative Example 1 and Comparative Example 2 made of monofilaments having circular cross- The circumferential length was larger at the same fineness. This means that the specific surface area of the fiber is large, so that excellent physical properties as described above can be realized. Also, since the fiber thickness is small at the same fineness, this can also realize excellent physical properties.

Here, the cross-sectional shape of the lyocell fiber of Example 1 is as shown in Fig.

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

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 exemplary and that the scope of the invention is not limited thereby. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

L1: center long axis length, S1: center short axis length,
L2: connecting straight line length of the center long axis end

Claims (3)

Cellulose pulp and a lyocell multifilament prepared by spinning a lyocell radial dope comprising a solvent,
Wherein the monofilament constituting the multifilament has a cross section having a central longitudinal axis (L1) and a central minor axis (S1), a length ratio between the central longitudinal axis (L1) and the central minor axis (S1) is 3.0 to 6.0: 1, Wherein the ratio of the length of the center long axis (L1) to the length of the straight line (L2) at both ends of the center long axis is 1.0 to 1.5: 1. The method according to claim 1,
Wherein the length of the center long axis (L1) of the monofilament is 12 to 42 mu m and the length of the center short axis (S1) is 4 to 7 mu m. The method according to claim 1,
Wherein the monofilament has a fineness of 1.0 to 4.0 denier and a value obtained by dividing a peripheral length of the monofilament by a fineness of 22 占 퐉 / denier or more.

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