KR101472098B1 - Manufacturing method of cellulose fiber using ionic liquid - Google Patents

Abstract

The present invention relates to a method for manufacturing a uniform cellulose fiber by manufacturing a cellulose solution using a solvent including an ionic liquid and containing constant moisture. To this end, provided is a method for manufacturing a uniform cellulose fiber comprising the steps of: dissolving an ionic liquid in which the moisture content of cellulose is 1 to 20% and manufacturing a cellulose solution; extruding and discharging the cellulose solution through a discharge nozzle and manufacturing discharge yarn; and passing the discharge yarn through an air layer, reaching a coagulation bath, coagulating, and washing and drying the same, and manufacturing the cellulose fiber.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing cellulose fibers using an ionic liquid,

The present invention relates to a method for producing cellulose fibers, and more particularly, to a method for producing cellulose fibers using an ionic liquid.

Cellulose is the most important renewable raw material and represents an important starting material for the textile, paper and nonwoven industries, for example. It also includes cellulose ethers such as methylcellulose and carboxymethylcellulose, cellulose esters based on organic acids such as cellulose acetate, cellulose butyrate and also cellulose esters based on inorganic acids such as cellulose nitrate, And as a raw material for derivatives and variants of cellulose. Such derivatives and variants have a variety of uses, for example in the food industry, the construction industry and the surface coating industry.

Cellulose fibers, such as cotton, rayon, and lyocell, are also used in the manufacture of fabrics and nonwoven fabrics.

Cellulose has a very high affinity with other materials but is difficult to dissolve in a general solvent due to a crystal structure formed by strong hydrogen bonding in a molecular chain or chain. Among the solvents capable of producing a solution by destroying this structure, NMMO (N-methylmorpholine-N-oxide).

The production process of cellulose fiber using NMMO solvent is more than 99% recovery of solvent and it is very high compared to other wet spinning. Very low concentration of NMMO is discharged from the process to the outside, but NMMO itself has low toxicity and is environmentally friendly, Point and manufactured fibers and films have high mechanical strength and are thus widely used in the manufacturing process of products made of cellulose. Many such methods have been proposed starting from US Pat. No. 3,447,935.

In U.S. Patent Nos. 4,142,913, 4,144,080, 4,196,282 and 4,246,221, NMMO aqueous solution containing not more than 50% water is subjected to vacuum distillation of water from NMMO aqueous solution containing cellulose swelling and swelling cellulose, And then extruded to make fibers.

US Pat. No. 4,416,698 and PCT International Publication No. WO 1997/47790, which disclose a method for producing a cellulose solution, have proposed a method for producing a cellulose solution through mixing, swelling and dissolution in an extruder.

However, as described above, cellulose fibers prepared by using NMMO as a solvent have a problem of low solubility and high crystallinity, and a high degree of crystallinity is a problem in that the solidification becomes rapid in a state where NMMO is spread at a very high rate in water during solidification .

An object of the present invention is to provide a method for producing a uniform cellulose fiber by preparing a cellulose solution containing an ionic liquid and containing a certain amount of water.

In order to accomplish the above object, the present invention provides a method for producing a cellulose solution, comprising: dissolving cellulose in an ionic liquid having a water content of 1 to 20% to prepare a cellulose solution; Extruding and spinning the cellulosic solution through a spinning nozzle to produce a discharged yarn; And passing the discharged yarn through an air layer to reach a coagulation bath, followed by coagulation and washing with water to produce a cellulose fiber.

Here, it is preferable that the ionic liquid has a water content of 5 to 10%.

In addition, the content of the cellulose powder is preferably 6 to 25% based on the total content of the cellulose solution.

In addition, the cellulose powder is preferably selected from the group consisting of wood pulp, cellulose, hemicellulose, linter, cotton and paper.

The ionic liquid may be at least one selected from the group consisting of dibutyl imidazolium acetate, dipentyl imidazolium acetate, dihexyl imidazolium acetate, dipropyl imidazolium octanoate Dipropylimidazolium octanoate, Dibutyl imidazolium octanoate, 1-Ethyl-3-methylimidazolium heptanoate, 1-ethyl-3-methyl Ethyl-3-methylimidazolium nonanoate, 1-ethyl-3-methylimidazolium octanoate, 1-ethyl- Ethyl-3-methyl imidazolium decanoate, 1-ethyl-3-methyl imidazolium undecanoate, 1-ethyl- 1-Ethyl-3-methyl imidazoli < / RTI > 1-ethyl-3-methyl imidazolium diethyl phosphate, diethyl imidazolium octanoate, 1-decyl-3-methylimidazolium diethyl phosphate, At least one liquid selected from the group consisting of 1-decyl-3-methyl imidazolium acetate and 1-ethyl-3-methyl imidazolium acetate desirable.

The present invention can produce uniform cellulosic fibers by using an ionic liquid as a solvent and containing a certain amount of water, reduce the energy cost in the concentration process due to the solvent reuse, can do.

Hereinafter, the present invention will be described.

The present invention relates to a method for producing cellulose by dissolving cellulose in an ionic liquid having a water content of 1 to 20% to prepare a cellulose solution; Extruding and spinning the cellulosic solution through a spinning nozzle to produce a discharged yarn; And passing the discharged yarn through an air layer to reach a coagulation bath, followed by coagulation and washing with water to produce a cellulose fiber.

The method for producing the cellulose fiber according to the present invention will be described in detail as follows.

First, a cellulose solution is prepared by mixing, swelling and dissolving an ionic liquid and a cellulose powder.

Here, the cellulose is not particularly limited as long as it is a cellulosic material. Examples of suitable cellulose materials include fibrous cellulose, hemicellulose, wood pulp, paper, linter, cotton Cotton), and the like, and mixtures thereof, but are not limited thereto.

The ionic liquid preferably has a water content of 1 to 20%, more preferably 5 to 10%. Thus, by dissolving the cellulose using an ionic liquid as a solvent, a uniform cellulose solution can be produced. In addition, by containing a certain amount of water in the solvent, energy loss can be prevented and process control can be facilitated.

On the other hand, the ionic liquid is not particularly limited, and examples thereof include dibutyl imidazolium acetate, dipentyl imidazolium acetate, dihexyl imidazolium acetate, dipropyl imidazolium acetate, Dipropylimidazolium octanoate, Dibutyl imidazolium octanoate, 1-Ethyl-3-methylimidazolium heptanoate, 1- (3-methylimidazolium heptanoate) Ethyl-3-methylimidazolium nonanoate, 1-ethyl-3-methylimidazolium octanoate, 1-ethyl- 3-methyl imidazolium decanoate, 1-ethyl-3-methyl imidazolium undecanoate, 1-ethyl-3-methylimidazolium undecanoate, -3-methylimidazolium dodecanoate < / RTI > Ethyl-3-methyl imidazolium dodecanoate, 1-ethyl-3-methyl imidazolium diethyl phosphate, diethyl imidazolium octylate, 3-methyl imidazolium acetate, 1-ethyl-3-methyl imidazolium acetate, and 1-ethyl-3-methyl imidazolium acetate. Lt; / RTI >

Such an ionic liquid has a high polarity and can change the rigid molecular structure of the cellulose, thereby improving the physical properties of the fiber.

On the other hand, the cellulose solution can be prepared by dissolving the cellulose powder in the ionic liquid and then adding a liquid for the non-solvent (for example, a liquid in which the cellulose is substantially insoluble, but can be miscible with the ionic liquid) .

The cellulose powder may be mixed with other polymer materials or additives. Examples of the polymer material include, but are not limited to, polyethylene, polyethylene glycol, polymethyl methacrylate, viscosity enhancer, titanium dioxide, silica dioxide, carbon, carbon nanotubes and inorganic nano clays. , Silica, carbon dioxide, carbon nanotubes, inorganic nano clay, and the like.

On the other hand, the content of the cellulose powder is preferably 6 to 25% by weight based on the total content of the cellulose solution, but is not limited thereto. When the content of the cellulose powder is in the above range, the efficiency of the spinning process described later can be increased.

By using the ionic liquid as a solvent, the cellulose solution prepared by the above method can form a large number of microstructures of the fiber because of its low solidification rate as compared with the case of using NMMO solvent and achieves a low degree of crystallinity .

Thereafter, the cellulosic solution is extruded and spun through a spinning nozzle to produce a discharged yarn.

The spinning nozzle is not particularly limited, but is an orifice having a diameter of 70 to 300 μm and a length of 140 to 2400 μm, wherein the ratio of the diameter to the length (L / D) is 2 to 10 times, and the distance between the orifices is 1.0 to Preferably a spinneret including a plurality of orifices having a diameter of 6.0 mm.

Further, the shape of the spinning nozzle is generally circular, and the nozzle diameter is 50 to 200 mm, more preferably 80 to 130 mm. When the nozzle diameter is less than 50 mm, the distance between the orifices is too short to lower the cooling efficiency of the solution, and the adhesion may occur before the discharged solution coagulates. If the nozzle diameter is too large, peripheral devices such as spinning packs and nozzles become large, . If the diameter of the nozzle orifice is less than 70 탆, a large number of yarn breaks occur at the time of spinning, which adversely affects radioactivity. If the diameter exceeds 300 탆, the coagulation speed of the solution in the spinning coagulation bath is slow, do. If the length of the nozzle orifice is less than 140 mu m, the orientation of the solution is poor and the physical properties are poor. If the length is more than 2,400 mu m, the manufacturing cost of the nozzle orifice is disadvantageously increased.

Thereafter, the discharged yarn is passed through an air layer to reach a coagulation bath, followed by coagulation, washing with water and drying to produce a cellulose fiber.

In this case, when the fibrous spinning solution (cellulose solution) passing through the spinning nozzle coagulates in the upper coagulating solution, the larger the diameter of the fluid, the greater the difference in the coagulation speed between the surface and the inside. It is difficult to obtain fibers.

Therefore, when the cellulose solution is spun, the spun fibers can be obtained in a coagulating solution having a smaller diameter while maintaining an appropriate air gap even at the same discharge amount. It is difficult to increase the air gap because too short air gap distance hinders the increase of the stretching ratio due to an increase in the micro void generation fraction generated during the rapid solidification of the surface layer and the desolvation process. On the other hand, when the air gap is too long, It is difficult to maintain process stability due to a relatively large influence of adhesion, atmospheric temperature, and humidity.

When passing through the air gap, the filaments are solidified to prevent fusion, and at the same time, air for maintaining a constant temperature and humidity is supplied in order to increase resistance to penetration into the coagulating solution, and an atmosphere of an air gap , Sensors are attached between the inlet of the feeder and the filament to monitor temperature and humidity to control temperature and humidity. In general, the temperature of the supplied air is maintained in the range of 5 ° C to 50 ° C. If the temperature is less than 5 ° C, the filament solidification is promoted, which is not only disadvantageous to high-speed spinning but also requires excessive cost for cooling. If the temperature exceeds 50 ° C, have.

The obtained multifilament is introduced into a washing bath and is then washed with water. As the filament passes through the coagulation bath, the desolvation and stretching, which have a great influence on the formation of the physical properties, are carried out at the same time, so the temperature and concentration of the coagulating liquid should be constantly controlled. The filament that has passed through the coagulation bath is flushed with a water bath, and the flushing method is not particularly limited as long as it is a method known in the art.

The washed multifilament is dried and emulsion-treated and wound. The drying, emulsion treatment and winding process are not particularly limited as long as they are methods known in the art. And is provided as the cellulose fiber through the above drying and winding process.

Hereinafter, the present invention will be described in detail with reference to examples. However, these examples are for illustrating the present invention specifically, and the scope of the present invention is not limited to these examples.

Example 1

A cellulose solution was prepared by dissolving 44 g of pulp in a solvent containing 356 g of 1-ethyl-3-methylimidazolium acetate and having a water content of 10%. Thereafter, the cellulose solution was extruded and spun through a spinning nozzle to produce a cellulose yarn.

Comparative Example 1

A cellulose yarn was prepared in the same manner as in Example 1, except that the pulp was dissolved in a solvent of 356 g containing 100% of 1-ethyl-3-methylimidazolium acetate.

Evaluation example

The uniformity of the cellulose solution prepared in Example 1 and Comparative Example 1 was visually observed and classified into excellent, normal, and insufficient. The results are shown in Table 1 below.

Moisture Content in Ionic Liquid (%) Dope uniformity Example 1 8 Great Comparative Example 1 0 usually

Claims (5)

Dissolving cellulose in an ionic liquid having a water content of 1 to 20% to prepare a cellulose solution;
Extruding and spinning the cellulosic solution through a spinning nozzle to produce a discharged yarn; And
Passing the discharged yarn through an air layer to reach a coagulation bath, coagulating and washing with water to prepare a cellulose fiber
≪ / RTI >
The method according to claim 1,
Wherein the ionic liquid has a moisture content of 5 to 10%.
The method according to claim 1,
Wherein the content of the cellulose powder is 6% to 25% based on the total content of the cellulose solution.
The method according to claim 1,
Wherein the cellulose powder is selected from the group consisting of wood pulp, cellulose, hemicellulose, linter, cotton, and paper.
The method according to claim 1,
The ionic liquid may be selected from the group consisting of Dibutyl imidazolium acetate, Dipentylimidazolium acetate, Dihexyl imidazolium acetate, Dipropylimidazolium acetate, octanoate, dibutyl imidazolium octanoate, 1-ethyl-3-methylimidazolium heptanoate, 1-ethyl-3-methylimidazole Ethyl-3-methylimidazolium nonanoate, 1-ethyl-3-methylimidazolium octanoate, 1-ethyl-3-methyl imidazolium nonanoate, Ethyl-3-methyl imidazolium decanoate, 1-ethyl-3-methyl imidazolium undecanoate, 1-ethyl-3-methyl imidazolium decanoate, 1-Ethyl-3-methyl imidazolium dodec anoate, 1-ethyl-3-methyl immidazolium diethyl phosphate, diethyl imidazolium octanoate, 1-decyl-3-methyl At least one liquid selected from the group consisting of 1-decyl-3-methyl imidazolium acetate and 1-ethyl-3-methyl imidazolium acetate And the crystallization degree can be controlled according to the solidification rate.