KR20180085858A - Eco-friendly addititives containing lyocell fibers - Google Patents

Abstract

The present invention relates to a method for producing an additive-containing lyocell fiber, which comprises the following steps: pulverizing cellulose by moisture management of a pulp sheet; swelling NMMO in an intermediate state between a liquid phase and a solid phase and powdered cellulose infinitely in a twin-screw extruder in the presence of additives; dissolving the mixture at a relatively low temperature within a short time using high shear force of the twin-screw extruder; and producing the mixture into a fiber. The additives added in the production of a cellulose dope give a change in the cross-sectional shape and a microstructure of yarn. Particularly, increased porosity increases the fatigue resistance of cellulose yarn and fibers.

Description

[0001] Eco-friendly addititives containing lyocell fibers [0002]

The present invention relates to a cellulose solution for producing cellulose fibers with improved fatigue resistance and a method for producing cellulose fibers, and more particularly, to a method for producing cellulose fibers by mixing NMMO and cellulose powder to prepare a cellulose dope, To a process for producing the same.

Cellulose has a very high affinity with other materials, but it is difficult to dissolve in a general solvent due to a crystal structure formed by a strong hydrogen bond in a molecular chain or a chain. NMMO is widely used as a solvent capable of producing a solution by destroying this structure .

Conventionally, the following technique is known as a method for producing a cellulose solution using NMMO hydrate.

U.S. Patent Nos. 4,142,913 and 4,144,080 disclose a method in which a solution in which cellulose is dissolved by distillation of celluloses swelled and dispersed in NMMO hydrate is obtained and cooled to prepare a solid precursor (a kind of chips) and then dissolved in an extruder to obtain cellulose Lt; / RTI > solution. Although this method can simplify the melting process by using an extruder, time and energy consumption are large due to the preceding process for chip formation, and there is a problem in temperature and humidity management of the precursor.

U.S. Patent No. 5,584,919 discloses a method for preparing a solid phase NMMO having a moisture content of 5 to 17%, followed by stirring in powdered cellulose and a horizontal cylindrical high-speed mixer to prepare a precursor on a granule and then dissolving in an extruder. This method has a problem that the particle size of the granule produced is large and the yield is low, which shows a larger dispersion as the capacity is increased and a complicated cooling device must be attached for transportation and storage. There is also the problem of preparation and storage of solid phase NMMO solvent.

U.S. Patent Nos. 5,094,690, 5,534,113 or 5,603,883 disclose a slurry in which cellulose is dispersed in NMMO containing 40% moisture, from a forced thin-film distillation apparatus capable of forming a thin film solution layer of 1.5 to 5.0 mm in excess water And then preparing a solution. In this method, evaporation and melting occur as the slurry descends downward due to the rotation of the rotor, so that it is difficult to give a sufficient shear force due to the short residence time as it is downstream in the vertical direction. It is inevitable to use a complicated vacuum distillation apparatus to evaporate the water to the required level within the solution retention time and the problem of inefficiency. This method has a problem of producing high-strength fibers because of low energy consumption due to a long time for the whole solution manufacturing process and low purification efficiency due to decomposition of cellulose and discoloration of NMMO.

According to U.S. Patent Nos. 5,421,525, 5,456,748, 5,534,113, or 5,888,288, pulverized pulp with non-uniform platelets and NMMO having a moisture content of 22% are mixed and swollen in a horizontal cylindrical mixer and then stored A method of dissolving water in a high-viscosity solution supplied to a forced thin-film evaporator while evaporating it is disclosed. In this method, the dust pulp generated in the production of the plate-like pulp must be separately managed, and the horizontal cylinder type mixer is difficult to discharge the swelling solution. In US Pat. No. 5,921,675, a conveyor screw A method of attaching the same has been disclosed.

According to U.S. Patent No. 5,948,905, NMMO hydrate having a moisture content of about 23% and water are evaporated in a cellulosic mixture to form a cellulose solution. The mixture is instantly vacuum evaporated while passing through a nozzle having a diameter of 1.5 to 6.0 mm In this case, in the first chamber, the nozzle diameter is increased and the number of holes is decreased. As the chamber stage is increased, the nozzle diameter is decreased and the number of holes is increased to increase the evaporation efficiency of the solution by increasing the cross- . The last step, Step 8, discloses a method of using an extruder. This method has a disadvantage in that the configuration of each chamber is different, and the number of screw and vacuum processing steps for chamber transfer is so large that the apparatus becomes complicated.

International Patent 97/47790 relates to a process for preparing a cellulose solution by directly dissolving a cellulose powder in a liquid NMMO solvent in a biaxial extruder. In this method, liquid NMMO having a moisture content of 12% is injected into the first barrel of the twin-screw extruder at a temperature of 100 ° C., and powdered cellulose of a third barrel adjusted to 75 ° C. is fed to a side feeder, The solution is prepared by raising the temperature. This method already occupies three barrels for the supply of cellulose and NMMO, and for the dissolution of cellulose in the extruder, a separate barrel for melting must be occupied. There is a short swelling zone in which swelling and dissolution almost coincide with each other. Therefore, there is a high possibility that undissolved cellulose particles are generated due to incomplete swelling of the pulp powder. It may be effective to prepare a small amount of the solution. However, when the amount of the cellulose solution produced increases, there is a problem in that excessive emission of the filter system and shortening of the radiation period are caused due to generation of a large amount of unhulled solution. If the swelling zone is increased, the melting zone is shortened and the barrel of the biaxial extruder is excessively increased. Even if the screw L / D is increased by increasing the block, since the same driving shaft is used, it is difficult to simultaneously control the swelling condition and the melting condition have. That is, the production of a solution with low-apparent-gravity powdery cellulose by a low-free-volume low-biaxial extruder may cause a problem in productivity.

Many patents and documents have been disclosed since Graenacher and Sallman in US Pat. No. 2,179,181 in 1939, and tertiary amine oxide as the most powerful solvent of cellulose by Johnson in British Patent No. 1,144,048 in 1966. Of these, NMMO is the most commonly used, and the oxygen group of the N-O group, which is an active part of NMMO, is easily intermolecularly bonded to a hydroxy-rich substance such as cellulose, thereby facilitating penetration into the crystal lattice of cellulose. In addition, Chanzy et al. Point out that NMMO has a difference in activity of reacting with cellulose depending on water and hydration degree and temperature.

However, as a factor affecting the reaction activity force, the inventors of the present invention have found that, in addition to the temperature, there is a relationship between the cellulose concentration, the DP of cellulose, the contact method and apparatus of cellulose and NMMO and the reaction active power depending on whether the NMMO is a liquid phase, .

As described above, in the conventional method, NMMO containing 20 to 40% of water is contacted with cellulose for the first time, and water is evaporated by using various types of evaporators to swell and dissolve. At this time, there are problems in transferring a high viscosity solution and a device for securing a sufficient residence time for evaporating water from a high viscosity solution, a vacuum device, and the like, which leads to a problem of large capacity and energy consumption. In addition, a method of directly dissolving by using liquid NMMO containing about 13% of water has been proposed. However, when it comes into contact with the cellulose at a temperature of about 80 ° C or more, which is the NMMO crystallization temperature at this time, It is dissolved immediately without swelling so that the un-dissolved components remain.

Morphology of the cellulose fibers of the pulp for dissolution shows that the pores through which water, called pits, pass and the thickness of the cell walls are not uniformly uniformed, so that it is difficult to locally penetrate and difficult to penetrate And the permeability of NMMO differs within a limited time. This tendency differs depending on the type of wood fiber used in pulp manufacture and the pulp manufacturing method. Therefore, in order to produce a homogeneous cellulose solution, the solvent used must sufficiently penetrate the entire surface of the cellulose fiber to relax or swell. Otherwise, there is a local difference in solubility in the cellulose fibers or between the fibers, so that complete dissolution does not occur and only limited dissolution occurs, resulting in unneeded cellulose remaining. In addition, fibrous celluloses are generally clustered in the manufacturing process. At this time, in the case of directly dissolving cellulose using a high concentration of NMMO, the dense state of the cellulose is a factor that affects the solubility. When the dense state of the cellulose is high, even if a strong shearing force is given or the NMMO swells or melts the outer surface of the cellulose bundle beforehand even if heated to a high temperature, it is difficult to further penetrate and remains as a cosolvent. From this viewpoint, it is an important technology for preparing a cellulose solution to control the dense state of cellulose and the reaction active power of NMMO.

As described above, in the conventional method, the complicated process which is disadvantageous for mass production, the decomposition of cellulose due to a long time for producing the solution, the burden of the purification process due to discoloration of NMMO, the decomposition of cellulose due to high temperature, the low homogeneity of the cellulose solution . The problem to be solved is the problem of low fatigue according to low power. In order to solve the above problems, it is ideal that the NMMO solvent is sufficiently infiltrated into the microstructure of the cellulose and the microstructure for a short time, low temperature and low shear force, swollen indefinitely, and then melted to prepare the cellulose solution for lyocell. In addition, the fatigue resistance can be improved by changing the cross-sectional shape and microstructure of the yarn by injecting the fatigue additive in the dope production process. In addition, it is an important technical task to produce a highly homogeneous, low-disintegration, and high-fatigue cellulose solution for lyocell fiber by avoiding complicated device structure for commercialization, dissolving large amounts of cellulose in a short time, and minimizing utility .

According to one embodiment of the present invention, a method for preparing a cellulose fiber using an NMMO / water mixed solvent includes the steps of: (a) preparing a concentrated liquid NMMO solution; (b) drying and pulverizing the cellulose sheet to prepare a cellulose powder maintained at 1 to 10% moisture; (c) measuring the additives of the liquid NMMO solution, cellulose powder and soybean oil, respectively, and injecting the mixture into a biaxial extruder, swelling and dissolving the cellulose to prepare a cellulose solution; (d) spinning the cellulose solution to prepare a cellulose filament.

According to another embodiment of the present invention, the additive for the soybean oil includes at least 3 and at most 15 epoxy groups in the molecular structure, and at least three alkyl group chains having at least 10 carbon atoms And the additive is added in an amount of 5% or less based on the total amount of the cellulose solution.

According to another embodiment of the present invention, there is provided a cellulose fiber produced by the method of claim 1, wherein the cross-sectional porosity of the cellulose fiber yarn is 0.5 to 50%.

According to another embodiment of the present invention, the cellulose solution prepared using the NMMO / water mixed solvent contains soybean oil additives in an amount of 5% or less based on the total amount of the solution, (a) a concentrated liquid NMMO solution Lt; / RTI > (b) drying and pulverizing the cellulose sheet to prepare a cellulose powder maintained at 1 to 10% moisture; (c) measuring the additives of the liquid NMMO solution, cellulose powder and soybean oil, respectively, and injecting the mixture into a biaxial extruder in the same direction to swell and dissolve.

The present invention relates to a process for pulverizing cellulose by pulverizing moisture of a pulp sheet, endless swelling of NMMO and powdered cellulose in a liquid phase and a solid phase in a twin-screw extruder in the presence of an additive, and then using a high shear force of the twin- At a relatively low temperature.

In particular, since the evaporation device for water by separate decompression is not necessary by directly injecting 86.5 wt% of concentrated NMMO, the structure of the device is simple. Also, by controlling the size and moisture of the powdery cellulose, swelling and dissolution of only the coating of the cellulose due to entanglement of the powdery cellulose can be prevented from becoming uncooled cellulose particles, thereby reducing the replacement period of the filter. By using a biaxial extruder having a high shear efficiency, the dissolution time and the melting temperature can be lowered and the degradation of the original pulp polymerization degree can be minimized. Therefore, the high cellulose lignocellulosic fiber can be produced with high molecular weight. The additives added in the preparation of the cellulose dope also change the cross-sectional shape and microstructure of the yarn. In particular, porosity increases, which increases the fatigue resistance of cellulose yarn and fibers.

FIG. 1 is a graph showing a state transition of NMMO according to the present invention.
FIG. 2 is a view showing a manufacturing process of a cellulose fiber according to an embodiment of the present invention.
3 is a view illustrating a process of manufacturing a cellulose solution according to an embodiment of the present invention.
4 is a SEM photograph of a fiber cross-section according to Example 1 of the present invention.
5 is a SEM photograph of a fiber cross-section according to Comparative Example 1 of the present invention

Hereinafter, preferred embodiments of the present invention will be described in detail. The present invention is not limited to the scope of the present invention, but is merely an example, and various modifications can be made without departing from the technical gist of the present invention.

In order to produce homogeneous lyocell fibers in which degradation of cellulose is minimized and unhulled cellulose particles are not present, it is necessary to uniformly mix the cellulose powder with the liquid phase of NMMO at a low temperature within a short time to sufficiently penetrate the NMMO into the cellulose powder A swelling process is indispensable.

In order to accomplish the above object, the present invention provides a method for producing a highly homogeneous cellulose solution for a lyocell, which uses a cellulose molecule having a high degree of polymerization to induce a high orientation structure and a high crystallinity, thereby achieving high strength and elasticity. In order to produce high-quality cellulose fibers, it is preferable to use cellulose having a high? -Cellulose content. Therefore, the cellulose used in the present invention is characterized in that pulp having a degree of polymerization (DPw) of 800 or more and an? -Cellulose content of 92% or more is used. The prepared cellulose sheet is passed through a dryer and then pulverized to obtain powdered cellulose containing 1 to 10 wt% or less, more preferably 1 to 5 wt% or less of water, and concentrated liquid NMMO in an amount of 50 to 100 At a rotating speed of 100 to 250 rpm, and swelling and dissolving the cellulose solution to prepare a cellulose solution for a lyocell.

If the moisture content is less than 1 wt%, the economical efficiency is deteriorated. If the moisture content is more than 10 wt%, the mechanical properties are deteriorated.

The cellulosic solution may comprise an additive of soybean oil. The additive of soybean oil plays a role in increasing fatigue resistance.

The present invention also relates to a process for preparing a concentrated liquid NMMO solution comprising: (a) preparing a concentrated liquid NMMO solution; (b) drying and pulverizing the cellulose sheet to prepare a cellulose powder maintained at a constant water content; (c) measuring the additives of the liquid NMMO solution, cellulose powder and soybean oil, respectively, and injecting the mixture into a twin-screw extruder to swell and dissolve the cellulose acylate solution.

More specifically, the highly homogeneous cellulose solution according to the present invention comprises

(a) concentrating 25% by weight of NMMO hydrate collected from wash liquor with 86.5% by weight of liquid NMMO (monohydrate) by means of a thin film drawdown condenser;

(b) After passing through a dryer while passing through a cellulose sheet on a roll, the cellulose sheet is treated to adjust the drying temperature so that the cellulose sheet has a moisture content of 7%. The cellulose sheet is immediately cooled with dry air and injected into a pulverizer. Preparing powdered cellulose;

(c) feeding the liquid NMMO and the cellulose powder prepared in (a) and (b) above to a twin-screw extruder adjusted to a temperature ranging from 50 to 100 ° C by adding an additive of soybean oil and dissolving Lt; / RTI > In particular, the twin-screw extruder prepared at this time minimizes the decomposition of the cellulose by arranging the screw to have a narrow residence time distribution.

U.S. Pat. No. 4,416,698 and International Publication No. WO 1997/47790 disclose a method of preparing a cellulose solution by injecting liquid NMMO and cellulose powder into an extruder, followed by mixing, swelling and dissolving, and Korean Patent Registration No. 10-0365867 The present invention relates to a method of dissolving NMMO in liquid phase and solid phase and cellulosic powder in which water content is not controlled and a cellulosic powder having no moisture content simultaneously in a single screw extruder. The mixture is first kneaded, kneaded and swollen, and then continuously swollen and dissolved in a twin-screw extruder. Thus, the manufacturing method and principle of the solution differ from those of the conventional patent.

The present invention also provides a method of preparing a liquid NMMO solution, comprising: (a) preparing a concentrated liquid NMMO solution; (b) drying and pulverizing the cellulose sheet to prepare a cellulose powder maintained at a constant water content; (c) measuring the additives of the liquid NMMO solution, the cellulose powder and the soybean oil, respectively; (e) injecting the cellulose paste into a biaxial extruder and swelling and dissolving the cellulose paste to prepare a cellulose solution; (f) spinning the cellulose solution to prepare a cellulose filament. The present invention also provides a method for producing a cellulose fiber.

The present invention also provides a cellulose fiber produced by the above production method. The cellulosic fibers produced according to the present invention are characterized in that the cross-sectional porosity of the yarn is 0.5 to 50%, more preferably 1 to 30%. As the porosity increases, the turnover increases and fatigue increases. When the porosity is less than 1%, the fatigue is decreased and it is not appropriate. When the porosity is more than 30%, the strength of the fiber is decreased, which is not suitable.

Hereinafter, a highly homogeneous cellulose solution for a lyocell according to the present invention and a method for producing the fiber will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a graph showing changes in the melting point-related phase of NMMO depending on the water content and temperature of the NMMO-water solvent system as disclosed by H. Chanzy in Carbohydrate Polymer 2. (1982) - It represents the process of swelling and dissolving as it spreads from the middle phase of the solid phase to the liquid phase. The 86.5 wt.% NMMO used in the present invention is already present in the liquid phase and the solid phase intermediate phase in the range of about 40-74 DEG C, as H. Chanzy has already shown in the OXIDE SYSTEMS document. Therefore, in the present invention, a novel homogeneous cellulose solution which can swell and dissolve by using a temperature rise and a shear force without a process of removing moisture at a temperature of 40 to 74 ° C. in which 86.5% by weight of NMMO has a mid- A manufacturing method is proposed.

2 schematically shows a process for producing the cellulose fiber of the present invention. 2, the pulp sheet 1 is pulled by the nip roller 5 and fed to the pulverizer 6. At this time, the pulp sheet 1 passes through the drying chamber 2 adjusted to a constant temperature, (3) and kept at 25 ° C. The drying temperature of the drying chamber 2 is controlled so that the water content does not exceed 7% by using the contact type moisture content measuring device 4 before passing through the nip roller 5. Generally, the pulp supplied has a moisture content of about 8 to 10%, but exhibits a variation in the moisture content of the powdered cellulose stored in the storage tank 10 after crushing according to seasonal humidity and temperature changes. If the water content is high, it is likely that the pulp is agglomerated and it is difficult to obtain a homogeneous solution. In addition, since the compositional deviation of the NMMO / cellulose / water is shown, the thickness of the fiber radiated through the nozzle 25 is also varied, so that uniform quality can not be obtained. The length of the powdered cellulose can be adjusted according to the size of the screen sieve mounted inside the knife-equipped grinder 6, and it is preferable to use a powder having a size of 500 μm or less, preferably 300 μm or less. When the thickness is 500 μm or more, the pulp agglomeration tends to occur when mixed with NMMO, which is an inhibiting factor for producing a homogeneous solution. The powdered cellulose having passed through the screen of the pulverizer 6 is supplied to the bag filter 8 through the air blower 7 so that the air is discharged to the outside and the powdered cellulose is discharged through the rotary valve 9 into the powdered cellulose reservoir 10 ). This powdered cellulose is fed into the extruder through a precise weight type metering device 11.

The 25 wt% NMMO aqueous solution is produced from a regeneration tank 15 recovered from a coagulation bath 13 and a water bath 14 and the regeneration tank 15 and the coagulation bath 13 are continuously exchanged, Concentration is maintained by% NMMO. The 25 wt% NMMO aqueous solution thus prepared is supplied to a purification column 17 using an ion exchange resin to remove ionic substances and carbonized impurities and is stored in the feed tank 18 of the concentrating column. And then supplied from the concentrating tower feeding tank to the three thin film descending type concentrating tower 19 in a sequential manner to prepare a final 86.5 wt% NMMO aqueous solution. The NMMO concentrated to 86.5% by weight is supplied to a jacketed storage tank 20 maintained at 90 캜, and is supplied to the extruder through a gear pump 21 in a quantitative manner.

The additive for soybean oil is a structure having at least three and no more than 15 epoxy groups in the molecular structure and at least three alkyl group chains having at least 10 carbon atoms and the additive is a cellulose solution Is added in an amount of 5% or less based on the total amount. An additive comprising an alkyl group having less than 3, more than 15, or less than 10 carbon atoms in the epoxy group or containing less than 3 alkyl chain is undesirable because it lowers the strength of the cellulose fiber, Are also undesirable because they degrade the strength of the cellulose fibers. The internal temperature of the twin-screw extruder is adjusted from 50 ° C to 100 ° C to dissolve after complete swelling by temperature rise and shear force. The dissolved cellulose solution passes through the filter 24 and the solution discharged through the nozzle 25 is formed into cellulose fibers after being subjected to the water washing 16 and the drying process 26.

3 is a schematic process drawing briefly showing a method for producing a cellulose solution of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

The solutions and fibers prepared in the examples were evaluated in the following manner.

(a) Weight average degree of polymerization (DPw)

The intrinsic viscosity [IV] of the dissolved cellulose was measured in a concentration range of 0.1 to 0.6 g / dl at 25 DEG C with a 0.5 M cupriethylenediamine hydroxide solution prepared according to ASTM D539-51T using a Ube load viscometer. The intrinsic viscosity is obtained by extrapolating the non-viscosity according to the concentration and substituting this into the Mark-Houwink equation to determine the degree of polymerization.

[IV] = 0.98 ^{- 2} DPw ^{0 .9}

(b) porosity (%)

The section of the yarn was photographed by SEM and calculated as the cross-sectional area of the void relative to the cross-sectional diameter area.

Porosity (%) = total cross-sectional area of void / yarn cross-sectional area X 100

≪ Examples 1-2 >

A cellulose sheet having a weight-average degree of polymerization of 960 to 980 (Buckeye V-81) was passed through a drying chamber and adjusted to a moisture content of 6.5 to 10%, and then passed through a pulverizer equipped with a screen- A cellulose powder having a moisture content of 3.5 to 7% is prepared, and liquid NMMO at 90 ° C, which is concentrated to 86.5% by weight through a thin film concentrating tower, is injected into a coaxial twin-screw extruder through a gear pump. At this time, 0.001% by weight of an antioxidant is added to and dissolved in concentrated liquid NMMO in the concentration process. The cellulose powder is quantitatively measured with a precision weight measuring device and then injected into a coaxial twin-screw extruder in the same direction so that the final concentration of cellulose dope becomes 11% by weight. At this time, soybean oil having 10 epoxy groups in the molecular structure and three alkyl chain having 15 carbon atoms is added as an additive to prepare a dope. The additive is added in an amount of 0.6 to 3.0% by weight based on the total weight of the dope. At this time, the biaxial extruder used was swollen and dissolved by keeping the barrel temperature of the initial supply part at 75 DEG C and the barrel temperature at the final discharge part at 95 to 105 DEG C, then passed through the filter and supplied to the nozzle through the gear pump . At this time, for the homogeneity evaluation of the solution, sampling was performed on the solution transfer line immediately after being discharged from the twin-screw extruder. The spinning conditions were applied as needed to industrial fibers. A nozzle having an orifice diameter of 150 mu m, an orifice gap of 1.5 mm and an orifice number of 900 was used. The length of the air layer was maintained at 80 mm. The temperature and relative humidity of the cooling air blown to the filament in the air layer were 20 ° C. and 45 RH%, respectively, and the air velocity was adjusted to 10 m / sec. The filaments flowing into the coagulating bath from the air layer were washed, washed, dried and emulsified. The fineness of the resulting multifilament was adjusted to 1500 denier. At this time, the concentration of the coagulating solution was 25% by weight of NMMO aqueous solution, and the coagulating solution temperature was 20 캜. The properties of the prepared cellulose solution and fiber were evaluated and are shown in Table 1 below.

≪ Comparative Example 1 &

Without adding additives The same method as in Example 1 was used. The properties of the prepared cellulose solution and fiber were evaluated and are shown in Table 1 below.

Figs. 4 to 5 are SEM photographs of fiber cross-sections according to Example 1 and Comparative Example 1. Fig.

division Additive ratio (wt%) Weight average degree of polymerization Porosity
(%) Yarn
Doubt (%) Example 1 0.6 980 One 6.3 Example 2 3.0 960 7 6.8 Comparative Example - 1090 0 6.1

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

1: pulp sheet 2: drying chamber
3: Dry air 4: Contact type water content measuring device
5: nip roller 6: crusher
7: blower 8: bag filter
9: Rotary valve 10: Storage tank
11: Weight type weighing device
13: Coagulation bath 14: Washing bath
15: regulating tank 16: water tank
17: refining tower 18: feed tank
19: concentrated tower 20: jacketed storage tank
21: Gear pump
23: Twin screw extruder 24: Filter
25: nozzle 26: dryer

Claims (4)

A method for continuously producing cellulose fibers using an N-methylmorpholine N-oxide (NMMO) / water mixed solvent,
(a) preparing a concentrated liquid NMMO solution;
(b) drying and pulverizing the cellulose sheet to prepare a cellulose powder maintained at 1 to 10% moisture;
(c) injecting the liquid NMMO solution, cellulose powder and soybean oil additives into a biaxial extruder, swelling and dissolving the solution to prepare a cellulose solution;
(d) spinning the cellulose solution to prepare a cellulose filament. The method according to claim 1,
The additive for the soybean oil is a structure having at least three and no more than 15 epoxy groups in the molecular structure and at least three alkyl group chains having at least 10 carbon atoms and the additive is a cellulose By weight based on the total weight of the solution. A cellulosic fiber produced by the method of claim 1, wherein the cellulosic fiber yarn has a cross-sectional porosity of 0.5 to 50%. In a cellulose solution prepared by using N-methylmorpholine N-oxide (NMMO) / water mixed solvent,
Characterized in that the solution contains not more than 5% of the additive of soybean oil in the total amount of the solution and is prepared by the following steps.
(a) preparing a concentrated liquid NMMO solution;
(b) drying and pulverizing the cellulose sheet to prepare a cellulose powder maintained at 1 to 10% moisture;
(c) adding the liquid NMMO solution and the cellulose powder to a twin-screw extruder by adding an additive of soybean oil to swell and dissolve the liquid NMMO solution;

Images