JP6403794B2 - Lyocell fiber - Google Patents

Description

  The present invention relates to lyocell fibers.

Fiber, when viewed in shape, means a natural or man-made linear object that is soft and thin and has a large ratio of length to thickness. Such fibers are classified into long fibers, semi-long fibers, and short fibers according to their shapes, and are classified into natural fibers and artificial fibers according to raw materials.

Since ancient times, fibers have been closely related to human life, but natural fibers such as cotton, hemp, wool and silk fibers have been used as the main raw material for clothing. Since the industrial revolution, with the development of science and technology, textiles have been used not only for clothing materials but also for industrial use. In addition, the artificial fiber field has been pioneered as a new fiber material to meet the rapidly increasing demand for fibers with the development of culture and population.

Among such artificial fibers, regenerated fibers not only have excellent touch and comfort, but also have a moisture absorption and discharge ability much faster than cotton, and have been used as raw materials for clothing. In particular, among such recycled fibers, rayon fibers have not only been able to realize the same feel as natural fibers, but also have excellent gloss and color development properties, and have been recognized as a harmless material for the human body in the past. Have been used extensively since. However, such rayon fibers have the characteristics of a material that often shrinks and wrinkles, and the manufacturing process is complicated, and many chemicals are used in the process of dissolving wood pulp and the like. It had the problem of causing environmental pollution in the process of environmental problems and wastewater treatment.

As a result, research has been conducted on fibers that are harmless to the environment and human body, and have better physical properties than other conventional fibers. Recently, lyocell fibers produced from natural pulp and amine oxide hydrate have been introduced. It was done. Such lyocell fiber has excellent fiber properties such as tensile properties and feel compared to conventional recycled fibers, but does not generate any contaminants in the production process, and the amine oxide solvent used is It is recyclable, biodegraded at the time of disposal, and used in various fields as an environmentally friendly fiber.

At present, however, only products with a circular cross-section can be produced as lyocell fibers, but it is expected that various physical properties can be exhibited depending on the cross-sectional shape of lyocell fibers. Is required.

An object of this invention is to provide a lyocell fiber with a large specific surface area.

Therefore, the present invention provides a lyocell produced by spinning a lyocell spinning dope comprising cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO) as a preferred first embodiment. The multifilament includes a monofilament having an irregular cross section, the irregular cross section includes a plurality of protrusions, and the plurality of protrusions includes a virtual first circle and an interior of the virtual first circle. In contact with the virtual second circle included in the center, but is formed integrally with the virtual second circle as a central part, and the end thereof has a shape in contact with the virtual first circle, Provide lyocell fiber.

The lyocell spinning dope according to the embodiment may include 6 to 16% by weight of cellulose pulp and 84 to 94% by weight of an aqueous N-methylmorpholine-N-oxide solution.

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 space occupancy defined by the following formula 1 may be 150 to 400% in the lyocell fiber according to the embodiment.
<Formula 1>
Space occupancy (%) = (imaginary first circle area / cross-sectional area of monofilament contained in lyocell fiber) × 100

The virtual first circle according to the embodiment may have a radius of 8 to 30 μm.

The virtual second circle according to the embodiment may have a radius of 3 to 12 μm.

According to the present invention, a lyocell fiber having a large specific surface area can be provided. Therefore, when this is used for a reinforcing material in the clothing, construction, or automobile fields, a smaller amount than that of a conventional lyocell fiber is used. Has the effect of exhibiting physical properties of the same level or higher.

The cross section of the monofilament contained in the lyocell fiber which concerns on one Embodiment of this invention is shown typically. It is a photograph which shows the cross section of the lyocell fiber manufactured by Example 1 of this invention. It is a photograph which shows the cross section of the lyocell fiber manufactured by Example 2 of this invention. It is a photograph which shows the cross section of the lyocell fiber manufactured by Example 3 of this invention.

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

The present invention comprises a lyocell multifilament produced by spinning a lyocell spinning dope comprising cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO), the multifilament comprising: The cross section is formed of a monofilament having a deformed cross section, and the deformed cross section includes a plurality of protrusions, and the plurality of protrusions includes a virtual first circle and a virtual second circle included in the virtual first circle. The present invention relates to a lyocell fiber, which is in contact with a circle but is formed integrally with the virtual second circle as a central part, and has a shape in contact with the virtual first circle.

[Multi-shaped cross section]
In the present invention, the irregular cross section means a shape including a large number of protrusions. Specifically, as shown in FIG. 1, the cross section has a large number of protrusions formed integrally with one central portion 1 as the center. It means a cross section.

Specifically, the deformed cross section is within a range of a virtual first circle 11 connecting the end points of each of a large number of protrusions and a virtual second circle 12 included in the virtual first circle 11. You can define its size and shape. At this time, the virtual first circle 11 and the virtual second circle 12 are circles in which the virtual first circle 11 has a larger radius than the virtual second circle 12 and have the same center. Although preferred, it need not have the same center.

The deformed cross section includes a plurality of protrusions, and the plurality of protrusions are formed integrally with the central portion 1 that overlaps the virtual second circle 12, but the end 5 of each protrusion is the virtual first circle. The indented portion 4 that is in contact with the one circle 11 and is formed between the protrusions has a shape that is in contact with the virtual second circle 12.

In the present invention, from the viewpoint of maximizing the specific surface area of the lyocell fiber, the irregular cross section may include three protrusions.

The virtual first circle has a radius of 8 to 30 μm, and the virtual second circle has a radius of 3 to 12 μm.

When the radius of the virtual first circle is 8 μm or more, it is possible to realize an irregular cross-sectional shape. When the radius of the virtual first circle is 30 μm or less, a monofilament having a fineness suitable as a fiber product is obtained. Can be formed. Moreover, when the radius of the virtual second circle is 3 μm or more, it is possible to realize an irregular cross-sectional shape, and when the radius of the virtual second circle is 12 μm or less, it has a fineness suitable as a textile product. Monofilaments can be formed.

The monofilament contained in the lyocell fiber according to the present invention has an irregular cross section as described above, and the lyocell fiber may have a space occupancy defined by the following formula 1 of 150 to 400%.

<Formula 1>
Space occupancy (%) = (imaginary first circle area / cross-sectional area of monofilament contained in lyocell fiber) × 100
Here, the space occupancy means the proportion of the space that the monofilament substantially occupies in the fibers due to the projections of the irregular cross section. That is, when the cross section of the monofilament contained in the lyocell fiber is a circular cross section, the cross sectional area of the actual monofilament and the area of the virtual first circle are the same, so the space occupancy defined as described above is In the case of a fiber having an irregular cross section including a protrusion, the actual area occupied by the fiber is increased by the protrusion. Therefore, it can be seen that the specific surface area of the fiber increases as the space occupancy increases.

The lyocell fiber of the present invention has a space occupancy rate defined by the above formula 1 of 150 from the viewpoint that various properties such as swelling characteristics, interfacial adhesion characteristics, and quick drying characteristics are excellent due to the effect of increasing the specific surface area. It is -400%, Preferably it is 300-400%.

On the other hand, the present invention comprises (S1) spinning a lyocell spinning dope containing cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO), and (S2) said (S1) Solidifying the lyocell spinning dope spun in the step to obtain a lyocell multifilament; (S3) washing the lyocell multifilament obtained in the step (S2) with water; and (S4) in the step (S3). A method of producing lyocell fibers comprising the step of emulsion treatment of water-washed lyocell multifilaments, wherein the multifilament comprises a monofilament having a cross-section of a cross-section, wherein the cross-section includes a plurality of protrusions, The protrusions of the virtual first circle and the virtual first circle In contact with the virtual second circle included in the center, but is formed integrally with the virtual second circle as a central part, and the end thereof has a shape in contact with the virtual first circle, The present invention relates to a method for producing lyocell fiber.

[Step (S1)]
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 includes 6 to 16% by weight cellulose pulp and 84 to 94% by weight N-methylmorpholine-N-oxide aqueous solution, and the cellulose pulp has an alpha cellulose content of 85 to 97% by weight. %, And the degree of polymerization (DPw) may be 600-1700.

If the cellulose pulp content in the lyocell spinning dope is less than 6% by weight, it is difficult to realize the fiber characteristics, and if it exceeds 16% by weight, it may be difficult to dissolve in the aqueous solution.

Further, in the lyocell spinning dope, when the content of the N-methylmorpholine-N-oxide aqueous solution is less than 84% by weight, the melt viscosity is significantly increased, which is not preferable, and when it exceeds 94% by weight, The spinning viscosity is greatly reduced, and it may be difficult to produce uniform fibers at the spinning stage.

The weight ratio of N-methylmorpholine-N-oxide to water in the N-methylmorpholine-N-oxide aqueous solution may be 93: 7 to 85:15. When the weight ratio of the N-methylmorpholine-N-oxide is more than 93, the dissolution temperature may be high and cellulose may be decomposed when dissolving the cellulose, and the weight ratio is less than 85. In such a case, the dissolution performance of the solvent may be reduced, making it difficult to dissolve the cellulose.

Using the spinning dope described above, this is discharged from the spinning nozzle of the spinneret. At this time, the spinneret serves to discharge the filamentous spinning dope into the coagulating liquid in the coagulating tank 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 ° C.

The spinneret may be a spinneret in which a large number of unit holes are formed when a large number of holes are set as one unit hole. At this time, the number of the many holes included in the unit hole may be the same as the number of the protrusions having the irregular cross section. For example, in order to manufacture a lyocell fiber including a monofilament having a modified cross section including three protrusions, the number of holes included in a unit hole may be three.

[Step (S2)]
The step (S2) is a step of solidifying the lyocell spinning dope spun in the step (S1) to obtain a lyocell multifilament, wherein the solidification in the step (S2) is performed by supplying cooling air to the spinning dope. A primary coagulation step by air quenching (Q / A) to be coagulated and a secondary coagulation step in which the primary coagulated spinning dope is immersed in a coagulation liquid and coagulated can be included.

In the step (S1), after the spinning dope is discharged from the spinneret, it can be passed through the air gap section between the spinneret and the coagulation tank. In such an air gap section, cooling air is supplied from the inside of the base to the outside from the air cooling portion located inside the donut-shaped base, and air quenching for supplying such cooling air to the spinning dope The primary coagulation can be performed by (air quenching).

At this time, the factors affecting the physical properties of the lyocell multifilament obtained in the (S2) stage are the temperature and the wind speed of the cooling air in the air gap section, and the solidification in the (S2) stage is performed at a temperature of 4 to 15 ° C. and 5 to 5 ° C. Cooling air having a wind speed of 50 m / s may be supplied to the spinning dope and solidified.

When the temperature of the cooling air is less than 4 ° C. during the primary solidification, the surface of the die is cooled, the cross-section of the lyocell multifilament becomes non-uniform, the spinning processability is deteriorated, and the temperature of the cooling air is When the temperature exceeds 15 ° C., the primary solidification by the cooling air is not sufficiently performed, so that the spinning processability is deteriorated.

Also, if the air velocity of the cooling air is less than 5 m / s during the primary solidification, the primary solidification by the cooling air is not sufficiently performed, so that the spinning processability is deteriorated and yarn breakage occurs, resulting in 50 m / s. In the case of exceeding the range, the spinning dope discharged from the die is swayed by air, so that the spinning processability is deteriorated.

After the primary coagulation by air quenching, the spinning dope is supplied to a coagulation tank containing a coagulation liquid so that secondary coagulation can proceed. On the other hand, the temperature of the coagulation liquid may be 30 ° C. or less for proper secondary coagulation. This is because the secondary solidification temperature is not higher than necessary, so that the solidification rate is maintained appropriately. Here, the coagulating liquid is not particularly limited because it can be manufactured and used with a normal composition in the technical field to which the present invention belongs.

[(S3) stage]
Step (S3) is a step of washing the lyocell multifilament obtained in step (S2) with water.

Specifically, after introducing the lyocell multifilament obtained in the step (S2) into the pulling roller, it can be introduced into a water washing bath and washed with water.

In the washing step of the filament, after washing with water, considering the ease of solvent recovery and reuse, a washing solution of 0 to 100 ° C. can be used, and water can be used as the washing solution, If necessary, other additive components may be further included.

[(S4) stage]
Step (S4) is a step in which the lyocell multifilament washed in step (S3) is subjected to an emulsion treatment, and can be dried after the emulsion treatment.

The emulsion treatment takes a form in which the multifilament is completely immersed in the emulsion, and the amount of the emulsion attached to the filament is kept constant by a pressing roller attached to the entry roll and the discharge roll of the emulsion treatment apparatus. The emulsion serves to reduce the friction that occurs when the filament contacts the drying roller and guide during the crimping stage.

The lyocell fiber as described above is environmentally friendly because it is biodegradable.

In addition, the lyocell fiber has a deformed cross-sectional shape in which the monofilament includes a large number of protrusions, so that the specific surface area is increased, and even if a small amount is used compared to the conventional lyocell fiber having a circular cross section, the lyocell fiber is equal to or higher than the same level. A lyocell fiber exhibiting physical properties can be produced.

In particular, the lyocell fiber according to the present invention has a large specific surface area. Therefore, when used in a reinforcing material for clothing, construction, or the automotive field, the lyocell fiber is equivalent or higher even if a small amount is used compared to the conventional lyocell fiber. There is an effect that can show the physical properties of.

When the lyocell fiber according to the present invention is used for clothing, it has excellent moisture absorption and quick drying due to the characteristic of large specific surface area, so there is no entanglement phenomenon on the body even if sweat is discharged, and the skin is always comfortable The state can be maintained to reduce discomfort. Furthermore, since it has an excellent cooling rate, rapid cooling can be maintained when sweat is continuously discharged. Specifically, the applicability range for clothing can include not only outdoor, sports, T-shirts, golf, men's and women's clothing, but also functional innerwear, hats, sports socks, underwear and the like.

When the lyocell fiber according to the present invention is used for a reinforcing material, the larger the contact area with the material to be reinforced, the greater the reinforcing function. MRG (Mechanical Rubber Good) such as tire cords and hose reinforcing materials, cement It can be applied to reinforcing materials, automobile interior materials and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. It will be apparent to those skilled in the art to which the present invention pertains that these examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention. It is.

Example 1
A cellulose pulp having a degree of polymerization (DPw) 820 and an alpha cellulose content of 93.9% was mixed with a NMMO / H ₂ O mixed solvent (weight ratio 90/10) having a propyl gallate content of 0.01% by weight to a concentration of 12% by weight. % Spinning dope for lyocell fiber production.

  First, the spinning dope maintains a spinning temperature from a spinning nozzle of a spinneret in which a large number of unit holes including three holes are formed at 110 ° C., and a single filament fineness is 3.37 denier. Spinning was performed by adjusting the discharge rate and spinning speed. The filamentous spinning dope discharged from the spinning nozzle was supplied to the coagulating liquid in the coagulating tank through the air gap section. At this time, in the air gap section, the cooling air primarily solidifies the spinning dope at a temperature of 8 ° C. and a wind speed of 10 m / s.

  As the coagulation liquid, one having a temperature of 25 ° C. and a concentration of 85% by weight of water and 15% by weight of NMMO was used.

At this time, the concentration of the coagulation solution was continuously monitored using a sensor and a refractometer.

The filament stretched in the air layer through the pulling roller is washed with a washing solution sprayed from a washing device to remove residual NMMO, and the emulsion is uniformly adhered to the filament, and then further squeezed to obtain the filament. The lyocell fiber containing multifilaments composed of monofilaments having a modified cross section including three protrusions was produced by maintaining the emulsion content with respect to that of 0.2% at 150 ° C. with a drying roller.

Example 2
A lyocell fiber including a multifilament made of a monofilament having a deformed cross section including three protrusions was produced in the same manner as in Example 1 except that the single fineness of the filament was 3.58 denier.

Example 3
A lyocell fiber including a multifilament made of a monofilament having a modified cross section including three protrusions was produced in the same manner as in Example 1 except that the single fineness of the filament was 14.82 denier.

Comparative Example 1
A single circular hole is used as a unit hole, and a spinneret in which a large number of the unit holes are formed is used, except that the single fineness of the filament is 1.73 denier, as in Example 1, A lyocell fiber including a multifilament made of a monofilament having a circular cross section was produced.

Comparative Example 2
A lyocell fiber containing a multifilament made of a monofilament having a circular cross section was produced in the same manner as in Comparative Example 1 except that the single filament fineness was 2.97 denier.

For the lyocell fibers produced in Examples and Comparative Examples, the cross-sectional shape, fineness and space occupancy of the monofilament contained in the lyocell fibers were measured and calculated by the following methods, and the results are shown in Table 1 below. Show.

(1) Cross-sectional shape of monofilament contained in lyocell fiber A small amount of fiber bundles are sampled, wound together with black cotton, thinned, inserted into a hole in a plate that can cut the cross section, and then a razor It was cut so that the cross-section was not pushed by the blade.

The cross section was magnified (× 200) using an optical microscope (BX51, manufactured by Olympus), and the image was stored with a digital camera. As the cross-sectional image of the fiber, the cross-section to be obtained was designated using the Olympus soft imaging solution program, and the radius and area were analyzed.

(2) Using the actual monofilament cross-sectional area of lyocell fiber and the density of lyocell fiber obtained by fineness cross-sectional analysis, the fineness of lyocell fiber was calculated by the following formula 2.
Density of lyocell fiber = 1.49 g / cm ³
<Formula 2>
Fineness (De) = [Lyocell fiber monofilament cross-sectional area (μm ² ) × Lyocell fiber density (g / cm ³ ) × 9000 (m)] / 1,000,000
(3) Space Occupancy The space occupancy of lyocell fiber was calculated by the following formula 1.

<Formula 1>
Space occupancy (%) = (imaginary first circle area / cross-sectional area of monofilament contained in lyocell fiber) × 100

As shown in Table 1, the lyocell fibers of Examples 1 to 3 composed of monofilaments having irregular cross sections have a space occupancy ratio as compared with the lyocell fibers of Comparative Examples 1 and 2 composed of monofilaments having a circular cross section. It turned out to be big. At this time, the cross sections of the lyocell fibers of Examples 1 to 3 are as shown in FIGS. 2a to 2c, respectively.

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

Although specific portions of the contents of the present invention have been described in detail above, such specific descriptions are merely preferred embodiments and are not intended to limit the scope of the present invention. It will be clear to those who have knowledge. Therefore, the substantial scope of the present invention should be defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1 Center part 2 Protrusion 3 Long axis of protrusion 4 Recessed part 5 End of protrusion 11 Virtual 1st circle 12 Virtual 2nd circle

Claims (3)

Comprising lyocell multifilament produced by spinning a lyocell spinning dope comprising cellulose pulp and an aqueous solution of N-methylmorpholine-N-oxide (NMMO),
The multifilament is composed of a monofilament with a cross section having an irregular cross section,
The profile section includes a number of protrusions;
The plurality of protrusions are in contact with a virtual first circle and a virtual second circle included in the virtual first circle, but are formed integrally with the virtual second circle as a central portion. , The end of which has a shape in contact with the virtual first circle,
The lyocell spinning dope comprises 6 to 16% by weight cellulose pulp and 84 to 94% by weight N-methylmorpholine-N-oxide aqueous solution ,
The virtual first circle has a radius of 8 to 30 μm,
The virtual second circle has a radius of 3 to 12 μm;
The virtual first circle and the virtual second circle have the same center,
The lyocell fiber characterized by the above-mentioned. The lyocell fiber according to claim 1, 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. The lyocell fiber according to claim 1, wherein the lyocell fiber has a space occupancy defined by the following formula 1 of 150 to 400%.
<Formula 1>
Space occupancy (%) = (imaginary first circle area / cross-sectional area of monofilament contained in lyocell fiber) × 100

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