KR20130035738A - Dope for spinning lyocell, method for preparing lyocell filament fiber, and lyocell filament fiber prepared therefrom - Google Patents

Abstract

The present invention provides a lyocell spinning dope, a method for producing a lyocell filament fiber using the same, and a lyocell filament prepared therefrom, which can provide a lyocell fiber exhibiting high strength and elongation with low fibrillation degree without additional processing. It is about a fiber. The lyocell spinning dope includes a first cotton linter pulp having a polymerization degree of 600 to 1200, a second cotton linter pulp having a polymerization degree of 1300 to 1800, or a wood pulp having a polymerization degree of 600 to 1200. Mixed pulp)); And N-methylmorpholine-N-oxide (NMMO) aqueous solution.

Description

Lyocell spinning dope, method for manufacturing lyocell filament fiber using the same, and lyocell filament fiber manufactured therefrom TECHNICAL FIELD

The present invention relates to a lyocell spinning dope, a method for producing a lyocell filament fiber using the same and a lyocell filament fiber produced therefrom. More specifically, the present invention provides a lyocell spinning dope, lyocell filament fiber using the same and lyocell fiber dope that can provide a lyocell fiber exhibiting high strength and elongation with low fibrillation without additional processing It relates to a lyocell filament fiber produced.

Fiber means a natural or artificial linear object that is flexible and thin when viewed in shape and has a large length to thickness ratio. These fibers are divided into long fibers, brisket fibers, and short fibers in terms of their shape, and are divided into natural fibers and artificial fibers in terms of raw materials.

In the past, textiles have been closely related to human life, and natural fibers such as cotton, hemp, wool and silk fibers have been used as the main raw material for coating. With the development of science and technology after the Industrial Revolution, textiles have been used not only for coating materials but also for industrial applications. To meet the demand of fibers, which have rapidly increased with the development of culture and population, the artificial fiber field has become a new fiber material. Pioneered.

The regenerated fibers in these artificial fibers not only have excellent touch and fit, but also have a much faster moisture absorption and discharge ability than cotton, and thus have been widely used as raw materials for coating. In particular, the rayon fiber of the regenerated fiber has excellent gloss and color development and can realize a touch equivalent to that of natural fibers, and has been widely used in the past because it is recognized as a material harmless to the human body. However, these rayon fibers had the characteristics of materials that shrink and wrinkle well, and many chemicals are used in the manufacturing process and the process of melting wood pulp, resulting in environmental pollution during operation and wastewater treatment. Had a problem causing.

Accordingly, researches on fibers that are harmless to the environment and the human body and which have excellent physical properties than other fibers have been conducted. Recently, lyocell fibers manufactured from natural pulp and amine oxide hydrates have been introduced. These lyocell fibers have superior tensile properties and tactile properties compared to conventional recycled fibers, and do not generate any contaminants in the production process, and the amine oxide solvents used are recyclable and biodegradable when disposed. As an eco-friendly fiber, it is used in various fields.

However, lyocell fibers have excessive fibrils formed on the surface due to high orientation and weak bonding force between fibrils, and thus, the surface texture of the fibers and the quality of the final product are deteriorated. In addition, additional steps such as acidic cellulase treatment are required to remove fibrils, which leads to complicated manufacturing processes, increased production costs, and a decrease in fabric weight and fiber properties during fibril removal. .

In addition, in order to more preferably use the lyocell fibers as industrial yarns, attempts have been made to improve the overall physical properties such as strength and elongation thereof.

Accordingly, while maintaining the properties of the eco-friendly lyocell fibers, it is possible to provide a high quality fiber with a low degree of fibrillation, but with improved strength and elongation by a simple process without adding a step for removing fibrils. Development of the method is required.

The present invention is to provide a lyocell spinning dope that enables the provision of lyocell fibers exhibiting high strength and elongation with low fibrillation without additional processing.

The present invention also provides a method for producing lyocell filament fibers using the lyocell spinning dope and lyocell filament fibers produced therefrom.

The present invention is a mixture comprising a first cotton linter pulp having a degree of polymerization of 600 to 1200 and a second cotton linter pulp having a degree of polymerization of 1300 to 1800 or a wood pulp having a degree of polymerization of 600 to 1200. pulp; And it provides a lyocell spinning dope comprising N-methylmorpholine-N-oxide (NMMO) aqueous solution.

In addition, the present invention comprises the steps of discharging the spinning dope from the spinneret; Passing the discharged dope through a coagulation bath to solidify the filament; Washing the filament having passed through the coagulation bath; And it provides a method for producing a lyocell filament fiber comprising the step of drying the washed filament.

The present invention also provides a lyocell filament fiber produced from the spinning dope.

Hereinafter, a lyocell spinning dope, a lyocell filament fiber manufacturing method, and a lyocell filament fiber according to a specific embodiment of the present invention will be described in detail.

According to one embodiment of the invention, a first cotton linter pulp having a polymerization degree of 600 to 1200 and a second cotton linter pulp having a polymerization degree of 1300 to 1800 or a wood pulp having a polymerization degree of 600 to 1200 pulp), including pulp); And a lyocell spinning dope comprising an aqueous N-methylmorpholine-N-oxide (NMMO) solution.

The inventors of the present invention are working to solve the biggest problem of lyocell fibers, high orientation and excessive fibrils formed on the fiber surface, and low elongation compared to viscose rayon, for example, a predetermined degree of polymerization of 600 to 1200. Applying a lyocell spinning dope containing a cotton linter pulp having a to a specific manufacturing method described below, the lyocell fiber has a low degree of orientation and fibrillation, and has a higher strength and elongation than ordinary lyocells using wood pulp The invention has been completed and confirmed that it can be provided. When the lyocell spinning dope is used, the amount of fibrils formed on the surface of the lyocell fiber or the degree of fibrillation is reduced, so that not only the surface texture of the fiber and the quality of the final product can be improved. By eliminating additional follow-up processes, the manufacturing process can be simplified and production costs can be reduced. In addition, the lyocell fiber obtained by using the lyocell spinning dope may have excellent strength and elongation, and thus may be applied to a fiber for tire cord.

In addition, by using the second side linter pulp having a polymerization degree of 1300 to 1800 together with the first side linter pulp having a polymerization degree of 600 to 1200, or using wood pulp having a polymerization degree of 600 to 1200 together, It was confirmed that various physical properties such as strength and elongation of the final lyocell fiber can be further improved.

Thus, the spinning dope according to one embodiment of the invention enables the provision of lyocell fibers exhibiting high strength and elongation with low fibrillation degree without additional processing.

Hereinafter, the spinning dope of one embodiment will be described in more detail.

The above-mentioned spinning dope includes a first side linter pulp having a predetermined degree of polymerization, or together with a second side linter pulp.

In general, cotton that has a long length of fiber separated primarily from seeds is called lint, and cotton that has a second length separated by fiber is called linter. Such printers typically have a fiber length of 3 to 5 mm and can be obtained from annual cotton, which is advantageous in terms of supply and demand of raw materials. The pulp obtained from this cotton linter may be referred to as cotton linter pulp, and in one embodiment, may be classified into first or second cotton linter pulp according to the degree of polymerization (DP).

The spinning dope may also comprise wood pulp with a first side linter pulp having a predetermined degree of polymerization. In this case, the wood pulp may refer to pulp derived from wood that has been generally used for the production of lyocell fibers. Such wood pulp includes softwood pulp, hardwood pulp, and the like. In one embodiment, the spinning dope includes softwood pulp.

On the other hand, the spinning dope of one embodiment is a first cotton linter pulp having a polymerization degree of 600 to 1200 and a second cotton linter pulp having a polymerization degree of 1300 to 1800 or a wood pulp having a polymerization degree of 600 to 1200 ( wood pulp), including mixed pulp. In this case, the degree of polymerization of each pulp may refer to the number of cellulose repeat units, that is, the degree of polymerization of cellulose repeat units in the polymer forming each pulp.

In this way, by including the first surface linter pulp together with the second surface linter pulp having a higher degree of polymerization, the physical properties such as strength and elongation of the initially produced lyocell fibers can be further improved. In addition, by including the wood pulp having a predetermined degree of polymerization together with the first surface linter pulp, providing a lyocell fiber exhibiting a relatively low fibrillation degree, excellent strength and elongation while reducing the production cost of lyocell fiber You can do it.

In addition, in the mixed pulp included in the spinning dope, the cotton linter pulp may include alpha-cellulose in a high content, for example, 99% by weight or more, and thus may exhibit a low degree of fibrillation, and It can be used as a fabric for high-quality apparel by containing a small amount. Furthermore, due to the high alpha-cellulose content of the cotton linter pulp, the mixed pulp may also comprise at least 97% by weight, preferably at least 98% by weight and more preferably at least 99% by weight of alpha-cellulose. With low fibrillation degree, it becomes possible to provide lyocell fibers exhibiting excellent overall physical properties.

On the other hand, the lyocell spinning dope may comprise 6 to 16% by weight of the mixed pulp described above. If the content of the mixed pulp is less than 6% by weight can not implement the fibrous properties, when it exceeds 16% by weight it may be difficult to dissolve in the aqueous phase.

In addition, the mixed pulp may include 50 to 90% by weight of the first cotton linter pulp, 10 to 50% by weight of the second cotton linter pulp, or 20 to 80% by weight of the first cotton linter pulp, and 20 to 80%. By weight woodpulp. When the mixed pulp contains an excessively high content of the second cotton linter pulp, the manufacturing processability of the lyocell fiber may be lowered due to the high degree of polymerization of the second cotton linter pulp. In addition, when the mixed pulp comprises an excessively high content of wood pulp, it may be difficult to provide lyocell fibers with low fibrillation, high strength and elongation.

In addition, the above-described lyocell spinning dope may include only the first and second facet linter pulp or two types of pulp of the first facet linter pulp and the wood pulp, but the wood together with the first and second facet linter pulp. Three or more pulp may be included, including pulp. In this case, the pulp content may be appropriately adjusted in consideration of the physical properties of the lyocell fiber to be obtained.

In addition, the lyocell spinning dope may contain 84 to 94% by weight of the aqueous solution N-methylmorpholine-N-oxide as a solvent component. When the content of the N-methylmorpholine-N-oxide aqueous solution is less than 84% by weight is not preferable because the melt viscosity is significantly high, if the content exceeds 94% by weight spinning yarn is significantly lowered to produce a uniform fiber in the spinning step Can be difficult.

The weight ratio of N-methylmorpholine-N-oxide and water in the N-methylmorpholine-N-oxide aqueous solution may be 91: 9 to 83:17. When the weight ratio of the N-methylmorpholine-N-oxide and water is greater than 91: 9, the dissolution temperature is increased, so that decomposition of cellulose may occur when dissolving cellulose, and when the weight ratio is less than 83:17, the solvent dissolution performance is low. It may be lowered and the dissolution of cellulose may be difficult.

The lyocell spinning dope is a mixture of pulp described above in an N-methylmorpholine-N-oxide aqueous solution containing N-methylmorpholine-N-oxide (NMMO) and water in a weight ratio of 90:10 to 50:50. After swelling, the weight ratio of N-methylmorpholine-N-oxide (NMMO): water is 93: 7 to 85:15, and the final content of the mixed pulp is 6 to 16% by weight, more preferably 10 to 14% by weight. It may be prepared according to a process of removing water if possible.

On the other hand, according to another embodiment of the invention, the step of discharging the above-mentioned lyocell spinning dope from the spinneret; Passing the discharged dope through a coagulation bath to solidify the filament; Washing the filament having passed through the coagulation bath; And it may be provided a method for producing a lyocell filament fiber comprising the step of drying the washed filament.

The inventors have found that applying the lyocell spinning dope comprising the mixed pulp described above to a particular manufacturing method solves the biggest problem of lyocell fibers, the high degree of orientation and excessive fibrils formed on the fiber surface and improved strength. Through experiments confirmed that it can provide an eco-friendly lyocell fiber showing the elongation and completed the invention. According to such a method for producing lyocell filament fibers, since a lyocell fiber having a very small amount of fibrils formed on the surface or a degree of fibrillation can be obtained, there is no need to install an additional process for removing fibrils. The process can be simplified and production costs can be reduced. In addition, according to the manufacturing method, it is possible to obtain a lyocell filament fiber having high strength and elongation and applicable to a tire cord which is an industrial material.

Since the content of the lyocell spinning dope has been described above, a detailed description thereof will be omitted.

The spinneret serves to discharge the filamentous filaments through the air duct to the coagulating solution. Discharging the spinning dope from the spinneret may be performed at 80 to 130 ° C.

In addition, after the spinning dope is discharged, the step of passing it through the air gap may be additionally performed. At this time, the air gap serves to pre-quench the liquid dope by supplying air to the dope discharged from the spinneret. At this time, since the drawing viscosity of the dope is higher than that of a general dope, the temperature of the supplied air is preferably 5 to 30 ° C, It may be 10 to 20 ℃.

In addition, the air volume of the air provided in the air gap may be 10 to 300 m ³ / hr, preferably 30 to 100 m ³ / hr. When the air flow rate is excessively small, it is not preferable to cut off due to non-uniform stretching. When the air flow rate is excessively large, cutting due to cooling of the spinneret occurs, which is not preferable.

The dope discharged from the spinneret and selectively passed through the air gap is solidified in the coagulation bath to form a filament, and the temperature of the coagulation bath may be 30 ° C. or less. This means that the solidification temperature is 30 ° C. or lower so that the solidification rate is properly maintained because the temperature is not too high. Here, the coagulation bath is not particularly limited because it can be prepared and used in a conventional composition in the art.

On the other hand, the lyocell filament fiber manufacturing method may include the step of washing the filament passed through the coagulation bath, and the step of drying the washed filament.

In the step of washing the filament passed through the coagulation bath, in consideration of the ease of recovery and reuse of the solvent after washing, it can be used as a washing liquid of 0 to 100 ℃ temperature, water may be used as the washing liquid, If necessary, other additives may be further included.

Drying the washed filaments may comprise applying a tension to the filaments at 0.1 to 2 g / d, preferably 0.2 to 0.5 g / d, at 80 to 200 ° C., preferably 100 to 150 ° C. Can be. The drying step may be carried out in a drying process of one step, it may also be proceeded to a multi-stage drying process to vary the drying process conditions by dividing the interval. Specific drying conditions of each step in the multi-stage drying process can be arbitrarily selected as necessary within the tension and temperature range, in addition to the above conditions, can be used in the technical field to which the present invention belongs.

On the other hand, Fig. 1 briefly illustrates an example of a spinning apparatus that can be used for producing lyocell filament fibers. Referring to the configuration of FIG. 1, the apparatus for manufacturing a lyocell multifilament of a general type includes a gear pump 11 for supplying spinning spinning solution at a constant pressure, and spinning caps spinning spinning spinning spinning solution from the extruder in the form of fibers. (12) A first coagulation bath (14) for solidifying the uncoagulated fiber (13) discharged from the spinneret is provided, and a second coagulation bath (15) is further provided if necessary. The filament that has passed through the coagulation baths 14 and 15 removes the solvent and the like contained in the spinning dope and the like by water in the washing device 17 by the driving of the traction roller 16. Subsequently, the filament passed through the washing apparatus may be dried in the drying apparatus 18 and then wound to obtain a final lyocell filament. However, this spinning device is only one example that can be used in the production of lyocell filament fibers, and the manufacturing method and manufacturing apparatus applicable to the present invention are not limited to the above description and FIG. 1.

Meanwhile, according to another embodiment of the present invention, lyocell filament fibers prepared from the lyocell spinning dope may be provided.

As described above, it has been found through experiments that lyocell spinning dope comprising at least one type of cotton linter pulp can be applied to a specific manufacturing method to provide lyocell fibers with low orientation and fibrillation. .

The lyocell fibers obtained by applying the lyocell spinning dope to a specific manufacturing method have a small amount of fibril or a degree of fibrillation formed on the surface. Such lyocell fibers, for example, because the degree of fibrillation is three or more, preferably one or more, not only the surface feel of the fiber and the quality of the final product, but also can have a low initial modulus It can be easily applied to high-quality garment fibers such as lining of clothes and undergarments.

The degree of fibrillation refers to the degree of fibril generation on the surface of the filament. Specifically, fibril is generated by rubbing the fibers with each other for a certain time based on the fibers in a state of being deposited in water, and the fibrillation is observed by an optical microscope. It may mean a value measured from the image obtained by. This "fibrillation degree" may be represented by the following general formula (1), and the lower the number of fibrils generated, the higher the degree of fibrillation that is closer to zero grade.

[Formula 1]

Fibrillation degree (grade) = number of fibrils per filament length (0.1 mm)

Class 0 = Fibrill 0

Grade 1 = number of fibrils <10

Tier 2 = number of fibrils <20

Tier 3 = number of fibrils <50

Grade 4 = number of fibrils <100

Grade 5 = number of fibrils> 100

※ In the fibrillation degree (grade), 0 grade is the highest grade.

As shown in Experimental Example 1 to be described later, the lyocell filament fibers may have an initial modulus of 150 to 250 g / d. In addition, the lyocell filament fibers may have a strength of 5 to 8 g / d and an elongation of 6.2 to 8.0%. The initial modulus, strength and elongation may be measured after drying the lyocell filament fibers prepared from the lyocell spinning dope in an oven at 105 ° C. for 2 hours.

According to the present invention, the fibrillation degree can be realized without an additional process, and has a high strength and elongation, and has a lyocell spinning dope that can provide a lyocell fiber that can be easily applied to high-grade garment fibers and industrial companies. Methods of making lyocell filament fibers and lyocell filament fibers made therefrom are provided.

1 is a simplified illustration of an example of a spinning apparatus that may be used to make lyocell filament fibers.

The invention is explained in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

Example: Preparation of lyocell filament fibers from cotton linter mixed pulp

Example 1

A first-side cotton linter pulp (provided by Minding) of a degree of polymerization (DP) 1200 was placed in a mill equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

A second cotton linter pulp (provided by Mint) of polymerization degree (DP) 1600 was put in a mill equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

The pulp powders DP1200 and DP1600 were mixed at a weight ratio of 8: 2.

The mixed pulp powder was swollen in 50 wt% NMMO aqueous solution. At this time, the content of pulp in the NMMO aqueous solution is 6% by weight, antioxidant was added to 0.01% by weight relative to the mixed pulp.

The swollen pulp slurry was maintained at an internal temperature of 90 ° C. and injected into a kneader maintained at an absolute pressure of 50 mmHg at a rate of 16 kg / hour using a rotary valve pump, while 50% by weight of NMMO aqueous solution was 89% by weight of aqueous NMMO solution. After the pulp was completely dissolved while removing excess water, the spinning dope was discharged through the discharge screw.

The spinning dope was adjusted so that the final filament total fineness was 1,650 denier, and was spun using a nozzle having 1000 nozzles and a nozzle cross-sectional area of 0.47 mm 2. At this time, an air gap of 30 mm was provided between the nozzle and the coagulation bath, and in the air gap, 15 ° C. cooling air was supplied to the dope discharged at a flow rate of 30 m ³ / hr.

The multifilament solidified in the coagulation bath after passing through the air gap was washed with water in a five-stage washing equipment, and then dried in a three-stage drying roll of an undried multifilament yarn having a water content of 170%. To obtain a lyocell multifilament yarn. At this time, the tension between the first and second stages of the drying roll was adjusted to 0.2 g / d, and the tension between the second and third stages was adjusted to 0.5 g / d, and the temperature of each drying roll was sequentially set to 100 ° C, 130 ° C, and 150 ° C. Adjusted to.

The filament number of the lyocell filament fibers produced by the above method was 1000 and the average fineness was 1.5 d.

Example 2

A first-side cotton linter pulp (provided by Mint) of a degree of polymerization (DP) 800 was placed in a grinder equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

A second cotton linter pulp (provided by Mint) of polymerization degree (DP) 1600 was put in a mill equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

The pulp powders DP800 and DP1600 were mixed at a ratio of 8: 2.

The lyocell multifilament fibers were obtained in the same manner as in Example 1 except that the first cotton linter pulp of the degree of polymerization (DP) 800 was used.

Example: Preparation of lyocell filament fibers from pulp mixed with cotton linter pulp and wood pulp

Example 3

A first-side cotton linter pulp (provided by Minding) of a degree of polymerization (DP) 1200 was placed in a mill equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

A softwood pulp sheet (V81 from Buckeye, polymerization degree 1200) was placed in a grinder equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

The two pulp powders above were mixed at a ratio of 5: 5.

The mixed pulp powder was swollen in 50 wt% NMMO aqueous solution. At this time, the content of pulp in the NMMO aqueous solution is 6% by weight, antioxidant was added to 0.01% by weight relative to the mixed pulp.

The swollen pulp slurry was maintained at an internal temperature of 90 ° C. and injected into a kneader maintained at an absolute pressure of 50 mmHg at a rate of 16 kg / hour using a rotary valve pump, while 50% by weight of NMMO aqueous solution was 89% by weight of aqueous NMMO solution. After the pulp was completely dissolved while removing excess water, the spinning dope was discharged through the discharge screw.

The spinning dope was adjusted so that the final filament total fineness was 1,650 denier, and was spun using a nozzle having 1000 nozzles and a nozzle cross-sectional area of 0.47 mm 2. At this time, an air gap of 30 mm was provided between the nozzle and the coagulation bath, and in the air gap, 15 ° C. cooling air was supplied to the dope discharged at a flow rate of 30 m ³ / hr.

The multifilament solidified in the coagulation bath after passing through the air gap was washed with water in a five-stage washing equipment, and then dried in a three-stage drying roll of an undried multifilament yarn having a water content of 170%. To obtain a lyocell multifilament yarn. At this time, the tension between the first and second stages of the drying roll was adjusted to 0.2 g / d, and the tension between the second and third stages was adjusted to 0.5 g / d, and the temperature of each drying roll was sequentially set to 100 ° C, 130 ° C, and 150 ° C. Adjusted to.

The filament number of the lyocell filament fibers produced by the above method was 1000 and the average fineness was 1.5 d.

Example 4

A first-side cotton linter pulp (provided by Mint) of a degree of polymerization (DP) 800 was placed in a grinder equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

A softwood pulp sheet (buckeye V-60, polymerization degree 800) was put in a mill equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

The two pulp powders above were mixed at a ratio of 5: 5.

The lyocell multifilament fibers were obtained in the same manner as in Example 3 except that the first cotton linter pulp of the degree of polymerization (DP) 800 was used.

Comparative Example: Fabrication of lyocell filament fibers from softwood pulp sheet

Comparative Example 1

A softwood pulp sheet (V81 from Buckeye, polymerization degree 1200) was placed in a grinder equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less.

The pulp powder was swollen in 50 wt% NMMO aqueous solution. At this time, the content of pulp in the NMMO aqueous solution is 6% by weight, antioxidant was added to 0.01% by weight relative to the softwood pulp.

The swollen pulp slurry was maintained at an internal temperature of 90 ° C. and injected into a kneader maintained at an absolute pressure of 50 mmHg at a rate of 16 kg / hour using a rotary valve pump, while 50% by weight of NMMO aqueous solution was 89% by weight of aqueous NMMO solution. After the pulp was completely dissolved while removing excess water, the spinning dope was discharged through the discharge screw.

The spinning dope was adjusted so that the final filament total fineness was 1,650 denier, and was spun using a nozzle having 1000 nozzles and a nozzle cross-sectional area of 0.47 mm 2. At this time, an air gap of 30 mm was provided between the nozzle and the coagulation bath, and in the air gap, 15 ° C. cooling air was supplied to the dope discharged at a flow rate of 30 m ³ / hr.

The multifilament solidified in the coagulation bath after passing through the air gap was washed with water in a five-stage washing equipment, and then dried in a three-stage drying roll of an undried multifilament yarn having a water content of 170%. To obtain a lyocell multifilament fiber. At this time, the tension between the first and second stages of the drying roll was adjusted to 0.2 g / d, and the tension between the second and third stages was adjusted to 0.5 g / d, and the temperature of each drying roll was sequentially set to 100 ° C, 130 ° C, and 150 ° C. Adjusted to.

The filament number of the lyocell filament fibers produced by the above method was 1000 and the average fineness was 1.5 d.

Comparative Example 2

A softwood pulp sheet (buckeye V-60, polymerization degree 800) was put into a grinder equipped with a 100 mesh filter to prepare pulp powder having a diameter of 1700 μm or less, and lyocell filament fibers were prepared in the same manner as in Comparative Example 1.

<Experimental Example> Measurement of physical properties of lyocell filament fibers of Examples and Comparative Examples)

Experimental Example 1 Measurement of Tensile Strength, Tensile Elongation and Initial Modulus

In accordance with the American Society for Testing and Materials (ASTM) D-885, the strength and elongation of the lyocell filament fibers obtained in the above Examples and Comparative Examples were measured at room temperature using a universal testing machine (Model 5566, Instron). For this measurement, the lyocell filament fibers obtained in Examples and Comparative Examples were dried in an oven at 105 ° C for 2 hours.

In addition, the initial modulus of elasticity of each lyocell filament fiber was measured under the conditions described below.

Specific measurement conditions are as follows, and the measurement results are expressed as the average value of 10 replicates.

 (1) tensile strength

1) Crosshead Speed: 300mm / min

2) Experimental error: ± 1 MPa

(2) Initial modulus

1) Head Speed: 300mm / min

2) Grip Distance: 250mm

3) 25 ℃ and 60RH% atmosphere

Experimental Example 2 Measurement of Alpha-cellulose Content in Raw Pulp

The pulp powder in Examples and Comparative Examples was immersed in a 17.5% NaOH solution at 20 ° C. for 20 minutes, and then the weight of the undissolved material was dried. At this time, the material that does not dissolve is alpha cellulose, the content was calculated according to the following general formula (2).

[Formula 2]

Alphacellulose content (%) of raw pulp = W / S x 100

[W = dry fiber dry weight (g), S = dry weight of pulp sample (g)]

Experimental Example 3 Measurement of Fibrillation

After injecting 0.1 g of a filament cut into 5 mm and a pure water 1 ml into a cylindrical cylinder having a diameter of 10 mm and a length of 30 mm and sealing it, the blood of the lyocell filament fibers obtained in the examples and the comparative example was obtained by using a device for reciprocating 10 times per second. The degree of fibrillation was measured. Specific measurement methods and conditions are as follows.

An image of fibrils generated by an optical microscope was analyzed to determine the number of fibrils generated per unit length. This "fibrillation degree" can be represented by the following general formula (1).

[Formula 1]

Fibrillation degree (grade) = number of fibrils per filament length (0.1mm) _

Class 0 = Fibrill 0

Grade 1 = number of fibrils <10

Tier 2 = number of fibrils <20

Tier 3 = number of fibrils <50

Grade 4 = number of fibrils <100

Grade 5 = number of fibrils> 100

The results of Experimental Examples 1 to 3 are shown in Table 1 below.

Spinning dope raw material Pulp degree of polymerization
(DP) Pulp
Mixing rate
(%) The tensile strength
(g / d)
Elongation
(%) Initial modulus
(g / d) Alpha-cellulose content of the raw pulp (wt%) Fibrillation degree Example 1 Cotton linter 1200 + 1600 80:20 7.9 7.8 240 99.5 One Example 2 Cotton linter 800 + 1600 80:20 7.6 7.3 225 99.5 One Example 3 Cotton Linter + Softwood Pulp 1200 + 1200 50:50 7.1 7.0 250 98.3 3 Example 4 Cotton Linter + Softwood Pulp 800 + 800 50:50 5.1 6.3 230 97.5 3 Comparative Example 1 soft
Wood pulp 1200 100 6.8 6.8 260 97.1 4 Comparative Example 2 soft
Wood pulp 800 100 4.7 5.9 240 95.5 5

Referring to Table 1, the lyocell filament fibers of Examples 1 to 4, while showing a low fibrillation degree compared to Comparative Examples 1 and 2, it was confirmed that the excellent tensile strength and tensile elongation, and also the initial modulus is low.

11: gear pump
12: Radiation Detention (12)
13: uncoagulated fiber
14: the first coagulation bath
15: Second coagulation bath
16: towing roller
17: flushing device
18: drying apparatus

Claims (11)

A first cotton linter pulp having a degree of polymerization of 600 to 1200,
Mixed pulp including second cotton linter pulp having a degree of polymerization of 1300 to 1800 or wood pulp having a degree of polymerization of 600 to 1200; And
A lyocell spinning dope comprising an aqueous N-methylmorpholine-N-oxide (NMMO) solution.
The method of claim 1,
6-16% by weight of mixed pulp; And
A lyocell spinning dope comprising 84-94 wt% of N-methylmorpholine-N-oxide aqueous solution.
The method of claim 1,
The mixed pulp is lyocell spinning dope comprising 50 to 90% by weight of the first cotton linter pulp, 10 to 50% by weight of the second cotton linter pulp.
The method of claim 1,
The mixed pulp is lyocell spinning dope comprising 20 to 80% by weight of the first cotton linter pulp, and 20 to 80% by weight of wood pulp.
The method of claim 1,
The wood pulp is lyocell spinning dope comprising soft wood pulp.
The method of claim 1,
The lyocell spinning dope in which the weight ratio of N-methylmorpholine-N-oxide and water in the N-methylmorpholine-N-oxide aqueous solution is 91: 9 to 83:17.
The method of claim 1,
The lyocell spinning dope wherein the mixed pulp contains 97% by weight or more of alpha-cellulose.
Discharging the spinning dope of any one of claims 1 to 7 from a spinneret;
Passing the discharged dope through a coagulation bath to solidify the filament;
Washing the filament having passed through the coagulation bath; And
Method for producing a lyocell filament fiber comprising the step of drying the washed filament.
The method of claim 8,
Discharging the spinning dope from the spinneret is a method for producing a lyocell filament fiber at 80 to 130 ℃.
9. The method of claim 8,
Drying the washed filament is a method of producing a lyocell filament fiber comprising the step of imparting a tension of 0.1 to 1 g / d to the filament at 80 to 200 ℃.
A lyocell filament fiber made from the spinning dope according to any one of claims 1 to 7.

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