KR100865135B1 - Production Method of Lyocell Filament for the Clothes - Google Patents

Abstract

The present invention is a lyocell filament for garments having a single yarn fineness of 0.5 to 3.0 denier, 20 to 300 denier yarn fineness, (a) when the lyocell filament measured in the dry state is subjected to an initial stress of 2.0 g / d 2 (B) lyocell filaments having a force-strain curve that stretches by at least% and stretches by at least 5% at 4.0 g / d.

Lyocell, N-methylmorpholine N-oxide, long fiber yarn, DP degradation rate, force-strain curve

Description

Production Method of Lyocell Filament for Clothing {Production Method of Lyocell Filament for the Clothes}

1 is a graph showing a stress-strain (SS) curve of a lyocell filament, (a) is a lyocell filament of Comparative Example 1, (b) is an SS curve of the lyocell filament of Example 1 It is shown.

2 is a schematic view showing a lyocell manufacturing process.

The present invention relates to a garment lyocell filament having a single yarn fineness of 0.5 to 3.0 denier, 20 to 300 denier yarn fineness, and a manufacturing method thereof, in particular by adjusting the force-strain curve of the lyocell filament according to the manufacturing process, A lyocell filament having strength and modulus suitable for use.

Cellulose fibers exhibiting excellent properties such as texture and luster, dyeability and drape of natural fibers have been proposed, including rayon fibers. However, in the case of the rayon fiber, the strength and modulus of the moisture are largely lowered, and thus, the fastness and the weather resistance of the fibers are evaluated. In addition, there is a disadvantage that the manufacturing process harmful to the human body by causing environmental pollutants such as sulfur dioxide (CS ₂ ), hydrogen sulfide (H ₂ S) at the time of manufacture. However, lyocell fibers manufactured using cellulose and N-methylmorpholine N-oxide (NMMO) solvents are pollution-free processes due to the recovery and reuse of the entire amount of the solvent, and the fibers and films produced have high mechanical strength. It is widely used in the production process of cellulose-based products, such a method for producing a lyocell fiber has been proposed a number of methods starting from US Patent No. 3,447,939.

US Patent Nos. 4,142,913, 4,144,080, 4,196,282 and 4,246,221 swell cellulose in an NMMO aqueous solution containing up to 50% water and distillate under reduced pressure from an aqueous NMMO aqueous solution containing swollen cellulose. After preparing the extrusion method was proposed to make a fiber. Since these methods take a long time from dissolution to spinning, the degradation rate of the degree of polymerization (DP) is increased by pyrolysis, which may result in a high fibrillation tendency. In addition, the amount of energy used is high, which can be a factor in increasing the manufacturing cost.

International Publication No. WO95 / 035399 discloses a method for producing fabrics by bleaching lyocell fibers in an aqueous sodium hypochlorite solution and then treating them with steam to reduce the degree of polymerization of the fibers by 200 or more to induce fibrils. However, this method is a method of producing staple fibers for fabrics.

According to this prior art, it can be seen that in order to obtain lyocell fibers having excellent physical properties, it is important to control the fibrillation tendency, particularly to suppress fibrils.

Therefore, in the present invention, the force-strain curve of the lyocell filament is adjusted to show high elongation under the initial stress, and the solution is prepared in a short time by directly dissolving the pulp in the liquid-concentrated NMMO to minimize the DP decrease rate, thereby reducing DP. By suppressing the generation of fibrils generated by the present invention, not only the strength and modulus were excellent, but also the lyocell filament for garments having excellent washing fastness, touch, gloss, and drape properties.

An object of the present invention is to provide a lyocell filament having a force-strain curve exhibiting high elongation under initial stress, thereby providing a lyocell fiber for garments excellent in washing fastness, feel, gloss and drape.

In addition, the present invention is to prepare a NMMO solution in a short time by dissolving 5.0 ~ 25.0% by weight of cellulose powder in the liquid concentrated NMMO, suppressing the generation of fibrils caused by DP lowering, clothing excellent in physical properties such as strength and modulus To provide a lyocell filament for.

According to a suitable embodiment of the present invention, there is provided a method for producing a cellulose sheet, the method comprising the steps of: (A) making a cellulose sheet into a cellulose powder: and supplying the cellulose powder and liquid concentrated N-methylmorpholine N-oxide (NMMO) to the extruder; Preparing a swelled and homogenized cellulose solution through an extruder in which screws are arranged to impart dispersion, mixing, shearing, kneading, dissolving and metering performance in the extruder, (B) the orifice number of After extruding through ˜200 spinning nozzles, the air passing through the air layer to reach the coagulation bath, (C) inside the coagulation bath is provided with a roller 7 for converting the filament in the horizontal direction, the roller ( 7) clothing comprising the step of adjusting the width of the filament in contact with the surface 500 to 2,000 mm ² to obtain the filament, and (D) washing, drying and tanning and winding while imparting shrinkage to the obtained filament A method for producing a lyocell filament for use is provided.

According to another suitable embodiment of the present invention, (1) 20 to 200 filaments, (2) 0.5 to 3.0 denier of single yarn fineness, 20 to 300 denier of yarn fine yarn, (3) 0.1 to 1.5 kgf of cutting load, ( 4) lyocell filaments with an elongation at break of 3.0 to 10.0%, and (5) a pulp-to-fiber DP reduction rate of 300 or less.

According to another suitable embodiment of the present invention, the cellulose powder is preferably 5000 µm or less in size.

According to another suitable embodiment of the present invention, the residence time in the extruder and the solution line of the step (a) is preferably within 30 minutes.

According to another suitable embodiment of the present invention, in the step (b), the air layer has a length of 10 ~ 200mm, the temperature of the air is 5 ℃ ~ 30 ℃, the relative humidity in the air layer is RH10% ~ RH50%, and the wind speed is It is preferable that it is 0.5-10 m / sec.

According to another suitable embodiment of the present invention, lyocell filaments having a fibril index of 4 or less may be provided.

Hereinafter, a method for preparing cellulose fibers, including the steps of preparing a solution, spinning, washing, drying and winding for the present invention, will be described in more detail.

The lyocell filament of the present invention is a lyocell filament composed of 20 to 200 filaments, and (a) the lyocell filament measured in the dry state is elongated by 2% or more when subjected to an initial stress of 2.0 g / d, and (b At 4.0 g / d, it has a force-strain curve that extends by at least 5%. The lyocell filaments having the force-strain curve of the present invention exhibit high elongation under initial stress, and thus have very good hand and drape as a garment fiber.

The present invention is to prepare a lyocell filament having a force-strain curve as described above, (A) the cellulose sheet to a cellulose powder: and cellulose powder and liquid-concentrated N-methylmorpholine N-oxide (NMMO) Feed to extruder; Preparing a swelled and homogenized cellulose solution through an extruder in which screws are arranged to impart dispersion, mixing, shearing, kneading, dissolving and metering performance in the extruder, (B) the orifice number of After extruding through ˜200 spinneret, reaching the coagulation bath by passing through the air layer, (C) inside the coagulation bath is provided with a roller (7) for switching the filament in the horizontal direction, the roller (7) The area of the filament in contact with the surface is 500 ~ 2,000 mm ² Adjusting to obtain a filament, and (D) washing and drying with water, drying and emulsifying while winding up the obtained filament.

In the present invention, a cellulose solution was prepared by dissolving a cellulose powder having a size of 5000 μm or less in a liquid concentrated NMMO using a twin screw extruder. At this time, the temperature of the swelling / kneading section was adjusted to 65-85 ° C. to induce swelling sufficiently, and the temperature of the dissolving section was adjusted to 90-110 ° C. to uniformly dissolve. In addition, the total residence time of the solution in the extruder and the solution line is adjusted to within 30 minutes to minimize the rate of DP degradation.

In the spinning process, an orifice having a diameter of 100 to 300 µm and a length of 200 to 2400 µm, wherein the ratio of the diameter to the length (L / D) is 2 to 8 times, and the number of orifices is 20 to 200 The spinning stock solution was extruded and spun.

When the fibrous spinning stock solution passed through the spinning nozzle is solidified in the upper coagulating solution, the larger the diameter of the fluid, the greater the difference in the coagulation rate between the surface and the inside, thus making it difficult to obtain a dense and uniform fiber. Therefore, when spinning the cellulose solution, even the same discharge amount can be obtained into the coagulating liquid with a smaller diameter while maintaining the appropriate air layer. Too short air gap distances increase the fraction of microvoids that occur during rapid surface layer solidification and desolvation, increasing the ratio of elongation, making it difficult to increase spinning speed, while too long air gap distances can affect the filament's adhesion, ambient temperature, and humidity. It is difficult to maintain process stability because it is relatively high.

Therefore, the air layer of this invention becomes like this. Preferably it is 10-200 mm, More preferably, it is 20-100 mm. When passing through the air layer, the filament is cooled and solidified to prevent fusion and at the same time to supply cooling air to increase the penetration resistance to the coagulating liquid, between the inlet of the cooling air supply device and the filament to grasp the atmosphere of the air layer Sensors are attached 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 30 ° C. If the temperature is less than 5 ℃ filament solidification is promoted not only disadvantageous to the high-speed spinning, but also excessive cost for cooling, and if it exceeds 30 ℃ the cooling effect of the discharge solution is likely to be easily broken.

In addition, the moisture content in the air is an important factor that can affect the filament coagulation process, the relative humidity in the air layer should be adjusted to RH10% ~ RH50%. More specifically, RH10% to RH30% of dried air in the vicinity of the nozzle and RH30% to RH50% of wet air in the vicinity of the coagulating solution can increase stability in terms of filament solidification rate and fusion of the spinneret surface. . The cooling air is blown horizontally on the side of the filament discharged vertically, and the wind speed is advantageously in the range of 0.5 to 10 m / sec, more preferably in the range of 1 to 7 m / sec. If the wind speed is too low, the cooling air cannot prevent other atmospheric conditions around the filament discharged to the air layer, and it is difficult to produce a uniform filament by causing a difference in the rate of solidification and trimming of the filament at which the cooling air reaches the latest on the spinning nozzle. If it is too high, the yarn filament shakes, causing the risk of sticking and impeding the uniform flow of coagulant, thus impairing the radiation stability.

The composition of the coagulation bath used in the present invention is such that the concentration of the NMMO aqueous solution is 5-40%. When the filament passes through the coagulation bath, if the spinning speed increases by 50 m / min or more, the coagulation fluid shakes due to friction between the filament and the coagulation solution. In order to improve productivity by increasing the excellent physical properties and spinning speed through the stretching orientation, this phenomenon is a factor that impairs process stability. Therefore, the design of the coagulation bath considering the size and shape of the coagulation bath and the flow and amount of coagulation fluid It needs to be minimized.

In the washing step according to the present invention, in order to impart a contraction, rollers having respective drive motors are positioned at the top and the bottom thereof so that the filament may travel and impart contraction by the speed difference between the upper and lower rollers at each stage. Adjusted.

The washed filament is dried and wound by winding. Drying, tanning and winding processes are in accordance with known conventional methods. It is used as a lyocell filament for clothing after drying and winding.

The lyocell filaments prepared according to the present invention have a force-strain curve that stretches at least 2% when the lyocell filaments measured in the dry state are subjected to an initial stress of 2.0 g / d, and at least 5% at 4.0 g / d. Has The lyocell filament having the force-strain curve of the present invention is initially prepared at an initial rate of 2.0 g / d by organically combining the filament manufacturing conditions presented above, in particular, the solution line residence time, air layer length, cooling wind velocity, cooling humidity and temperature. A lyocell filament with a force-strain curve of a yarn suitable for apparel yarns stretching at least 2% when stressed and at least 5% at 4.0 g / d is completed.

The factor influencing the force-strain curve of the present invention is the crystal orientation of the filament. The crystal orientation is preferably 0.80 or more, and more preferably 0.90 or more. If the crystal orientation is less than 0.8, it is impossible to have the force-strain curve of the present invention due to insufficient molecular chain orientation and due to the strong fall of the filament. Process factors affecting the crystal orientation include the concentration of lyocells to the solvent, the length / diameter ratio of the orifice, the cooling conditions, the coagulation bath temperature, the stretching temperature and the stretching ratio, and the like. By appropriately adjusting these various process factors, the crystal orientation of the filament can be adjusted to 0.80 or more.

Another factor influencing the force-strain curve of the present invention is the density of the filaments. It is preferable that the density of a filament is 1.25-1.34g / cm <^3> , More preferably, it is 1.29-1.32g / cm <^3> . If there are many voids in the filament, or excessively developed into a skincore structure, the filament has a density of less than 1.25 g / cm ³ and thus lacks compactness and strength and thus does not have the force-strain curve of the present invention. Exceeding 1.34 g / cm ³ leads to an excessive reduction in cord elongation. In particular, process factors affecting the density of the filament include the concentration of lyocells to the solvent, the diameter / length ratio of the nozzle, the air layer length, the cooling conditions, the solidification bath composition ratio, and the solidification bath temperature. By appropriately adjusting these various process factors, the density of the filament can be adjusted in the above preferred range.

A factor which greatly affects the filament force-strain curve of the present invention is the contact area of the yarns in the roller 7 which switches in the horizontal direction inside the solidification bath 6. By adjusting the contact area of the yarns, a desirable force-strain curve of the filament of the present invention can be obtained. The multifilament introduced into the coagulation bath 6 has a contact area of a constant width with the roller 7 installed inside the coagulation bath. The area where the multifilament yarns contact the roller surface is preferably 500 to 2,000 mm ² . If the area where the multifilament yarn contacts the surface of the roller 7 is smaller than 500 mm ² , the percentage of micropores generated during the desolvation of the solvent present in the multifilament is excessively increased and the density of the monofilament is too low, making it difficult to stretch. On the contrary, if the area where the multifilament yarn contacts the surface of the roller 7 is larger than 2,000 mm ² , problems such as pin yarn caused by the contact between the roller 7 and the filament may occur, resulting in poor process stability. Therefore, the filament must be adjusted properly so as to have a proper contact area to obtain maximum elongation.

In order to adjust the area in which the multifilament yarns contact the roller surface, it is possible to adjust the yarn width wound on the roller by applying a guide of a certain shape to maintain a constant spread of the yarn on the roller. For example, if the guide shape is a narrow v-groove, the width of the yarn is reduced, and thus the contact area is reduced. If the guide is flat, the width of the yarn is increased and the contact area is increased.

Hereinafter, the configuration and effects of the present invention will be described in detail with specific examples and comparative examples, but these examples are only intended to clearly understand the present invention and are not intended to limit the scope of the present invention. The physical properties of the yarns prepared in Examples and Comparative Examples were evaluated in the following manner.

(a) Degree of polymerization (DP _w )

Intrinsic viscosity [IV] of dissolved cellulose is 0.5M cupriethylenediamine hydroxide solution made according to ASTM D539-51T using Uberod viscometer at 25 ± 0.01 ℃ and concentration range of 0.1 ~ 0.6 g / dl Measured. Intrinsic viscosity is obtained by extrapolating specific viscosity according to concentration, and substituting this into Mark-Houwink's formula to obtain polymerization degree.

^{[IV] = 0.98 × 10 -2} DP w 0 .9

(b) cutting load (kgf) and cutting elongation (%)

After standing at 20 ° C. and 65% RH for at least 24 hours, the sample was dried at 107 ° C. for 2 hours, and then measured at 200 mm and a tensile rate of 200 mm / min using an Instron low speed tensile tester.

(c) fibril index

The cellulose fiber prepared in the present invention was evaluated for the fibrillation index (F.I.) using the following method. To force fibrils into a 250 ml Erlenmeyer Flask (narrow neck) containing 25 ° C water, 50 multifilaments 10 mm in length and 10 magnetic 5 mm metal balls The fibrillation index (FI) was evaluated through an optical microscope after rotating for 30 minutes at 10 rpm using a stirrer (magnetic bar 40L x 10 mmφ).

Samples of the fibers were arranged according to the increase in fibrillation. From each sample, the reference fiber length is measured, the number of fibrils according to the reference field is counted, the length of each fibrils is measured, the average fibrillation length is calculated, and the value obtained by multiplying the number of fibrils is determined for each fiber. It was.

The fiber showing the highest value is the most fibrillated fiber, the fibrillation index 10 is set to any value as a reference, the fibrillation index is set to 0 for the fibers that are not fibrillated as a whole, and the rest The fibers were arranged in a range of 1 to 10 by setting appropriate values according to the degree of fibrillation.

<Examples 1, 2, 3>

A V-60 cellulose sheet of Buckeye, USA having a weight average degree of polymerization of 850 was placed in a grinder equipped with a 100 mesh size filter to prepare a cellulose powder having a size of 5000 µm or less, and the cellulose powder was dissolved in NMMO. At this time, the antioxidant for preventing oxidation of NMMO and solution was dissolved to 0.075% by weight based on the final cellulose.

Using the extruder as a screw feeder, the cellulose solution was allowed to rise to 65-85 ° C. in the extruder swelling zone to sufficiently swell the cellulose powder in the NMMO solution, and then each block temperature in the dissolution zone of the extruder was 95-110 ° C. The screw was operated at 200 rpm to dissolve completely and then discharged through the nozzle.

At this time, the DP reduction rate was minimized by adjusting the residence time of the solution from the extruder to the spinning nozzle.

With the cellulose solution, the final filament fineness was adjusted to 50 to 200 denier and was wet and dry spinning.

Detailed spinning conditions and fiber characteristics analysis results are shown in Table 1.

TABLE 1

sample Example 1 Example 2 Example 3  Cellulose Concentration (%) 9.5 10.5 12.0  Extruder Swelling Section Temperature (℃) 63 72 81  Extruder final block temperature (℃) 95 97 102  Solution residence time (min) 15 20 26  Fiber denier after spinning 55 70 150  Degree of filament polymerization after spinning 590 680 640  Filament Cutting Load (kgf) 0.22 0.32 0.56  Filament Cutting Elongation (%) 6.2 6.8 8.8  Fibril Index 4 4 4  % Elongation at 2.0 g / d 2.5 2.7 3.2  % Elongation at 4.0 g / d 6.1 6.4 6.7  Crystallization Orientation 92 93 96  density 1.295 1.298 1.302 Roller and Four-contact Area (mm ² ) 1200 1500 800

<Comparative example 1, 2, 3>

In Comparative Examples 1 and 2, the contact area between the roller and the yarn was 2500 and 400 mm ² , respectively. It was manufactured under the same conditions as in Example 2 except for changing.

Comparative Example 3 was prepared under the same conditions as in Example 2 except that the solution residence time was changed to 34 minutes.

TABLE 2

sample Comparative Example 1 Comparative Example 2 Comparative Example 3  Cellulose Concentration (%) 10.5 10.5 10.5  Extruder Swelling Section Temperature (℃) 72 72 72  Extruder final block temperature (℃) 97 97 97  Solution residence time (min) 20 20 34  Fiber denier after spinning 70 70 70  Degree of filament polymerization after spinning 680 680 680  Filament Cutting Load (kgf) 0.35 0.37 0.38  Filament Cutting Elongation (%) 4.5 4.8 4.6  Fibril Index 6 7 8  % Elongation at 2.0 g / d 1.9 1.6 1.8  % Elongation at 4.0 g / d 4.9 4.4 4.4 Crystallization Orientation 88 82 73 density 1.260 1.268 1.260 Roller and Four-contact Area (mm ² ) 2500 400 1500

The present invention directly dissolves 5.0-25.0% by weight of cellulose powder in liquid-concentrated N-methylmorpholine N-oxide (NMMO) and shortens the residence time in the solution line within 30 minutes to prevent the lowering of DP. It is possible to manufacture the lyocell filament for garments with suppressed generation. In addition, the lyocell filaments of the present invention (a) when the lyocell filament measured in the dry state subjected to the initial stress of 2.0g / d elongated by 2% or more, (b) at 4.0g / d elongated by 5% or more Since it has a force-strain curve, that is, exhibits high elongation under initial stress, it can have very good hand and drape as a garment fiber. In addition, the lyocell filament for garments produced according to the present invention may have excellent physical properties, for example, touch, gloss, strength retention during moisture absorption, and the like.

Claims (3)

(A) making the cellulose sheet into cellulose powder, and feeding the cellulose powder and liquid concentrated N-methylmorpholine N-oxide (NMMO) to the extruder, dispersing, mixing, shearing, kneading, dissolving in the extruder and Preparing a swelled and homogenized cellulose solution through an extruder in which screws are arranged to impart metering performance; (B) extruding the cellulose solution through a spinning nozzle having an orifice number of 20 to 200, and then passing the air layer to reach a coagulation bath; (C) In the coagulation bath, a roller 7 for converting the filament in the horizontal direction is provided, and the width of the filament in contact with the surface of the roller 7 is 500 to 2,000 mm ^2. Adjusting to obtain a filament; And (D) a method for producing a lyocell filament for clothing comprising the step of winding by washing, drying and emulsion treatment while imparting shrinkage to the obtained filament. The method of claim 1, The residence time in the extruder and the solution line in the step (A) is characterized in that less than 30 minutes. (a) the lyocell filaments measured in the dry state elongate at least 2% when subjected to an initial stress of 2.0 g / d, and (b) have a force-strain curve elongating at least 5% at 4.0 g / d. A lyocell filament having the physical properties of the. (1) Filament number 20 to 200, (2) Single thread fineness 0.5 to 3.0 denier, Yarn fineness 20 to 300 denier, (3) Cutting load 0.1 to 1.5 kgf, (4) Cutting elongation 6.0 to 10.0%, (5) Pulp DP lower from fiber to fiber less than 300 (6) Fibrillation index 4 or less

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