KR101627768B1 - Process for preparing lyocell filament fiber, lyocell filament fiber, and tire cord - Google Patents

Abstract

The present invention relates to a method for producing a lyocell, comprising the steps of spinning a dope for making a lyocell, producing a filament by solidifying the dope to be radiated, washing the filament, drying the washed filament, and winding the dried filament And a process for loosening and maintaining the moisture content of the filament at 10% or less between the drying step and the winding step. The present invention also relates to a method for manufacturing a lyocell filament, a lyocell filament fiber, and a tire cord.

The present invention relates to a process for producing a lyocell filament fiber having excellent properties by improving the stretching property and processability of the fiber by performing the relaxation process by effectively controlling the moisture content of the filament between the drying step and the winding step in the spinning process of the lyocell filament fiber .

Tire cord, lyocell, spinning, drying, coiling, moisture, relaxation rate

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a lyocell filament fiber, a lyocell filament fiber, and a tire cord,

The present invention relates to a method for producing a lyocell filament fiber, a lyocell filament fiber, and a tire cord.

The tire is a composite of fiber / steel / rubber and has a structure as shown in Fig. That is, steel and fiber cords reinforce the rubber and form the basic skeleton structure within the tire. In other words, it is like a bone in comparison with a human body.

Performance requirements for cords as tire reinforcement are fatigue resistance, shear strength, durability, rebound resilience and adhesion to rubber. Therefore, a proper material cord is used according to the performance required for the tire.

The rayon and polyester are used for body fly (also referred to as carcass) (6 in Fig. 1), nylon is mainly used for cap In the ply (4 in Fig. 1), and steel and aramid are mainly used in the tire belt section (5 in Fig. 1).

The following is a brief description of the tire structure shown in Fig. 1 and its characteristics.

Tread (1): It is a part that comes into contact with the road surface, it should provide friction force necessary for braking and driving, good abrasion resistance, able to withstand external impact, and low heat generation.

Body Ply (or Carcass) (6): It is a coil layer inside the tire. It should support the load and resist the impact.

Belt (5): It is located between the body fly, and it is made of steel wire in most cases, it alleviates the external impact and keeps the ground surface of the tread wide to improve the running stability.

Side Wall (3): A rubber layer between the lower portion of the shoulder (2) and the bead (9), and protects the inner body ply (6).

BEAD (9): A square or hexagonal wire bundle with rubber coated wire to seat and fix the tire on the rim.

Inner Liner (7): Located inside the tire instead of the tube, it prevents air leakage and enables pneumatic tires.

CAP PLY (4): It is a special cloth paper placed on the belt of the radial tires for some passenger cars, minimizing the movement of the belt when driving.

APEX (8): It is a triangular rubber filling material used to minimize the dispersion of beads, protect the beads by mitigating external impact, and prevent the inflow of air during molding.

Materials commonly used for tire cords include nylon, polyester, and rayon. Due to the advantages and disadvantages of each of these materials, the specifications and applications of the tire to be used are limited.

Nylon fibers have high tensile elongation and strength and are mainly used in heavy trucks subjected to heavy loads and tires used on bendy roads such as unpaved roads. However, the nylon fiber is not suitable for passenger car tires, which have intensive heat accumulation inside the tire, are low in modulus, travel at high speed, or are required to ride comfortably.

Polyester fibers are superior in shape stability and price competitiveness compared to nylon, and their strength and adhesion are improved due to continuous research, and the use of polyester fibers is increasing in the field of tire cords. However, since heat resistance and adhesive force are still limited, it is not suitable for high-speed driving tires.

Rayon fibers, which are regenerated cellulose fibers, exhibit excellent strength retention and shape stability at high temperatures. Therefore, rayon fiber is known as an optimal tire cord material. However, because of the strong drop in strength due to moisture, it is necessary to thoroughly control the moisture in tire manufacturing, and the generation rate of defective products is high due to nonuniformity in the production of yarn. Above all, it has a very low price / performance ratio compared to other materials and is mainly applied to high-speed or high-priced tires.

Therefore, research on improving rigidity and low elongation of the structure of the lyocell filament fiber is needed in the production of a tire cord excellent in high-speed running property and shape stability in the past.

The present invention provides a method for producing lyocell filament fibers which improves the stretching properties and processability of the lyocell filament fibers and prevents damage to the filaments.

The present invention also provides a lyocell filament fiber excellent in durability and stability and a tire cord comprising the same.

The present invention relates to a method for producing a lyocell, Solidifying the emitted dope to produce a filament; Washing the filament with water; Drying the washed filament; And winding the dried filament, wherein the step of loosening and maintaining the moisture content of the filament at 10% or less between the drying step and the winding step is provided.

The present invention also provides a lyocell filament fiber having a tensile strength of 5 to 9 g / d and an elongation of 6 to 9%.

The present invention also provides a tire cord comprising the lyocell filament fibers.

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

In the present invention, a filament bundle comprising a plurality of filament fibers is referred to as a 'multifilament,' and a raw cord produced from the upper and lower margins (or lower and upper margins) of the multifilament is referred to as' A dip cord treated with an adhesive for a tire cord in the composite yarn is referred to as a " tire cord " or a " cord ".

The lyocell filament fiber to be developed in the present invention has an optimum physical property for use as a tire cord, and has particularly improved elongation and strength.

The present inventors have conducted a relaxation process while maintaining the moisture content of the filament (moisture weight ratio relative to the dried yarn) at 10% or less between the drying step and the winding step in the spinning process of the lyocell filament, thereby ensuring excellent spinning stability, The present inventors have found out that a Lyocell filament fiber having a modulus can be produced, and the present invention has been completed.

Hereinafter, a method of manufacturing a lyocell filament fiber according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

The method of producing the lyocell filament fiber of the present invention is not particularly limited to the following preferred embodiments, and it will be understood by those skilled in the art that various modifications and equivalents may be made thereto There will be.

Accordingly, the scope of the present invention is not particularly limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the claims are also within the scope of the present invention.

FIG. 2 is a schematic view showing an example of a spinning device for producing lyocell filament fibers according to an embodiment of the present invention. 2, the apparatus for manufacturing a lyocell multifilament according to the present invention comprises a gear pump 11 for supplying a radial dope at a constant pressure, a spinning and spinning mechanism for spinning the spinning dope supplied from the extruder in the form of fibers, (12), and a first coagulation bath (14) for coagulating the non-coagulated filament fibers (13) discharged from the spinneret, and further includes a second coagulation bath (15) if necessary. The filaments that have passed through the coagulation baths 14 and 15 remove solvents and the like contained in the spin doses and the like by water in the flushing device 17 by driving the rollers 16 of the towing section. Then, the filament that has passed through the flushing apparatus is dried in the drying device 18, and then wound to wind the filament, thereby obtaining the final lyocell filament.

According to an embodiment of the present invention, there is a feature that the moisture content of the filament is maintained at 10% or less and relaxed between the drying device 18 and the winding step. When the moisture content of the filament exceeds 10%, sufficient elongation and strength can not be imparted to the lyocell filament fiber. In particular, when the moisture content exceeds 10%, further relaxation due to moisture may occur, resulting in fluctuation of the filament during the subsequent process, resulting in lowering of the working efficiency and lowering process stability. Further, excess moisture is evaporated in a subsequent step to relax the relaxed state and the filament is pulled, thereby reducing the relaxation rate, which may deteriorate physical properties such as elongation of the lyocell filament fiber. However, conventionally, the water content of the filament fibers is not controlled, and the physical properties of the lyocell filaments are lowered. However, in the present invention, by controlling the moisture content of the filament fibers within a specific threshold range as described above, it is possible to secure the excellent physical properties of the fibers while improving the stretching property and the coarseness of the fibers.

In the present invention, the moisture content of the filament may be controlled to be less than 10% by controlling drying process conditions, or may be controlled using a heating bar after the drying process.

More specifically, the method of controlling the moisture content of the filament can be controlled by winding the filament fibers sequentially by hot rolls of different temperatures at various temperatures using a Nelson type hot roll immediately before winding, and then loosening the filament fibers. That is, the filament fiber may be wound on a hot roll having a temperature of 120 to 150 ° C of the Nelson type immediately before winding, loosened and rewound, and the moisture content may be adjusted.

Also, in the present invention, the relaxation process can impart a relaxation rate of 1 to 5% to the filament by using a difference in advancing speed of the filament in two or more rolls.

The relaxation step is to adjust the first in the mounted first roll filament running speed (V ₁₎ and the advancing speed the filaments in a second roll mounted subsequently (V ₂₎ from among the at least two rolls mounted between the drying step and the winding step A relaxation rate can be imparted to the filament. Further, the present invention can provide an effective relaxation rate to the filament by adjusting the filament traveling speed (V ₁ ) of the first roll to be greater than the filament traveling speed (V ₂ ) of the second roll subsequently mounted.

As shown in FIG. 2, in the present invention, the filament running speed V ₁ of the first roll may be the advancing speed of the filament in the last roll of the drying device 18 before the dried filament is discharged, The filament traveling speed V ₂ of the _two rolls can be represented by the traveling speed V ₂ at which the dried filament is wound on the wind-up roll 19 mounted on the following winding portion. Also, the relaxation rate of the filament may be adjusted by controlling the speed of the at least one roll of the drying apparatus shown in Fig. For example, adjusting the first mounting of the first traveling speed in the drying roll filament (V ₁₎ in a drying apparatus, and by controlling the filament running speed (V ₂₎ in the second drying rolls mounted subsequently, relaxation of the filament fiber Rate can be given.

Also, in the present invention, the relaxation process may be performed by further attaching a towing device including at least one tow roll between the drying step and the winding step.

Meanwhile, the lyocell filament fiber of the present invention is prepared by dissolving cellulose in a mixed solvent of N-methylmorpholine-N-oxide (hereinafter referred to as NMMO) and water using the above-described production apparatus to prepare spinning dope; Spinning a cellulose-based filament from the spinning solution using a spinning device equipped with a spinning nozzle; And washing and drying the irradiated cellulose-based filaments.

The dope for preparing the lyocell according to the present invention may be any spinning solution commonly used in the production process of the lyocell filament fiber, and may be cellulose, N-methylmorpholine-N-oxide, or the like. NMMO) and water can be used.

The spinning dope can be prepared according to a conventional method, and is not particularly limited. However, cellulose is added to an NMMO aqueous solution containing N-methylmorpholine-N-oxide (NMMO) and water in a weight ratio of 93: 7 to 85:15 By weight to 7 to 18% by weight. In addition, the viscosity of the spinning dope is preferably maintained at 8,000 to 25,000 Poise.

The spinning process using the spinning dope can be carried out according to a generally known method, preferably by spinning the spinning dope at a temperature in the range of 80 ° C to 130 ° C. Further, the filament spun through the spinneret is solidified by passing through a coagulating solution. In this case, the temperature of the coagulating solution may be from -20 ° C to 30 ° C in terms of controlling the coagulation speed of the filament, have.

In the present invention, the coagulating solution is not particularly limited as it can be prepared and used in a conventional composition in the technical field. Preferably, N-methylmorpholine-N-oxide (NMMO) And water may be used. In the coagulating solution, the weight ratio of NMMO and water in the coagulating solution may be adjusted to 5:95 to 25 to maximize the spinning efficiency of the filament so that the melting point of the solvent is increased or the coagulation temperature is appropriately maintained. : 75 can be used.

In the present invention, the filament may be passed through a coagulating solution and then further processed without a separate additional coagulating bath. If necessary, after passing the filament through a first coagulating solution as shown in Fig. 2, And further passing through the step of passing. At this time, the temperature and composition of the second coagulating liquid are the same as those of the above-described temperature and composition of the coagulating bath.

Thereafter, the filaments solidified in the coagulation bath are applied to the flushing apparatus 17 so as to remove the remaining NMMO, and NMMO can be removed with the flushing liquid in consideration of the ease of recovery and reuse of the solvent after flushing. At this time, water may be used as the washing liquid, and other additional components may be further included if necessary.

Then, the filament that has passed through the water washing device 17 is dried through a drying device 18, and then wound to wind the filament, thereby obtaining a final lyocell filament.

At this time, the present invention is characterized in that the present invention includes a step of loosening and maintaining the moisture content of the filament at 10% or less between the drying step and the winding step, wherein the relaxation step is performed by using the filament running speed difference in two or more rolls So that the filament can be imparted with a relaxation rate of 1 to 5%. When a relaxation ratio is given between the drying step and the winding step, it is possible to prevent the fiber from being damaged and to exhibit excellent physical properties in the cord.

In the present invention, the drying may be performed at a temperature of 90 to 200 ° C or 100 to 150 ° C. The drying step may be a one-stage drying step, or may be divided into a plurality of sections and may be performed in a multi-stage drying step with different drying process conditions. The drying conditions of each step in the multi-step drying step may be arbitrarily selected within the above-mentioned temperature range, and conditions other than the above conditions may be used in the technical field of the present invention.

The lyocell filament fibers of the present invention produced by the above method have a total fineness of 200 to 3000 denier, a tensile strength of 5 to 9 g / d, preferably 6.5 to 7.5 g / d, an elongation of 6 to 9% Preferably 6.5 to 8.5%, and these lyocell fibers can be used as industrial fibers such as materials for tire cords and the like.

The tire cord of the present invention comprises said lyocell filament fiber. The tire cord may include the lyocell filament fibers in the form of a combined filament of 2 to 3 ply having a total filament number of 400 to 6000, a total fineness of 400 to 9000 denier, and a twist number of 200 to 600 TPM.

The lyocell tire cord of the present invention is excellent in shape stability and durability and can be applied to a body fly of a pneumatic tire or a cap fly.

The tire cord of the present invention is produced by twisting the lyocell filament fibers to produce a combined yarn of 2 to 3 ply, treating the combined yarn with an adhesive solution for a tire cord according to a conventional dipping method, Followed by heat treatment.

The adhesive solution may be a conventional tire cord impregnating solution, preferably a resorcinol-formaldehyde-latex (RFL) adhesive solution.

The cords passing through the adhesive solution are made from a tire cord through a drying process and a heat treatment process. The drying process is performed at a temperature of 105 to 160 ° C for 1 to 10 minutes at a tensile force of 20 to 2000 g / cord, and the heat treatment process is performed at a tensile force of 20 to 2000 g / cord at 105 to 220 ° C for 1 to 10 minutes can do.

In the drying process, moisture present in the lyocell is dried. In the heat treatment process, an impregnating solution is reacted to give adhesion force to the tire cord.

In the present invention, matters other than those described above can be added or subtracted as required, and therefore, the present invention is not particularly limited thereto.

The process of producing a lyocell filament according to the present invention is to control the moisture content of the filament between the drying step and the winding step to thereby ensure a good radiation stability and prevent damage to the yarn, The cords exhibit excellent elongation and strength properties.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Example  One

A pulp having a degree of polymerization (DPw) of 1,200 and an a-cellulose content of 97% was mixed with an NMMO / H ₂ O mixed solvent (weight ratio 90/10) having a propyl gallate content of 0.01% by weight to prepare a dope for preparing a lyocell with a concentration of 11% .

The lyocell filament fiber was prepared by spinning, coagulating, washing with water, and drying using a spinning apparatus based on the same configuration as shown in FIG. 2.

The preparation dope was maintained at a spinning temperature of 110 ° C. in the spinning nozzle of the spinneret 12 and the spinning rate was adjusted by controlling the discharge amount and spinning speed so that the final filament fineness was 1,650 denier.

Uncoagulated fibers 13 discharged from the spinning nozzle were radiated to a first coagulation bath 14 and a second coagulation bath 15. The coagulated liquid was conditioned at a temperature of 25 캜 and at a concentration of 85% by weight of water, 15% by weight of NMMO %. At this time, the coagulating liquid concentration of the coagulating bath was continuously monitored using a sensor and an refractometer.

The filaments passing through the coagulating solution were dried in a roll of the drying unit 18 and then taken up to produce a lyocell filament fiber by removing the remaining NMMO by the wash liquid sprayed in the water washing unit 17. At this time, the moisture content of the filament was adjusted to be about 9% between the drying step and the winding step.

The moisture content of the filaments was controlled by winding the filament fibers around the hot rolls in different stages at different temperatures using a Nelson-type hot roll immediately before winding, and then loosening the filaments. That is, the filament fiber was wound on a hot roll having a temperature of 120 to 150 ° C of the Nelson type immediately before winding, loosened and rewound, and the moisture content was adjusted.

2, the filament running speed V ₁ of the last drying roll (first roll) of the drying apparatus was adjusted to 105 m / s, and the winding roll (second roll) mounted on the succeeding winding section The filament running speed (V ₂ ) was adjusted to 100 m / s, and the filament was given a relaxation rate of 5% using the speed difference of the drying roll.

Example  2

The filament running speed (V ₁ ) was adjusted to 103 m / s in the first drying roll of the drying part, and the filament progressing speed was adjusted in the second drying roll The same procedure as in Example 1 was repeated to adjust the speed (V ₂ ) to 100 m / s and to give a 3% relaxation rate to the filament using the speed difference of the drying roll, .

Example  3

The filament running speed (V ₁ ) was adjusted to 101 m / s in the first drying roll of the drying section, and the filament running speed in the second drying roll The same procedure as in Example 1 was repeated except that the speed (V ₂ ) was adjusted to 100 m / s and the filament was given a relaxation rate of 1% by using the speed difference of the above-mentioned drying roll to prepare a lyocell filament fiber Respectively.

Comparative Example  One

The same procedure as in Example 1 was repeated except that the moisture content of the filaments was adjusted to about 11% between the drying step and the winding step, thereby producing the lyocell filament fibers.

Comparative Example  2

The same procedure as in Example 1 was repeated except that the water content of the filaments was adjusted to about 13% between the drying step and the winding step and the filament running speed was set to be the same between the drying step and the winding step, Fibers were prepared (no relaxation rate).

Experimental Example

The properties of the dope and filament fibers prepared according to Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated by the following methods.

(a) Strength (g / d) and elongation (%)

The specimens were dried at 110 ° C for 2 hours to preliminarily dry to a process water content of less than 24 hours and then allowed to reach equilibrium in the moisture state in the standard state (25 ° C, 65RH%) of KSK 0901 And then dried at 105 DEG C for 2 hours.

The dried test pieces were measured for tensile strength and elongation at a sample length of 250 mm and a tensile speed of 300 m / min using a low speed stretching type tester manufactured by In-rlton Co., Ltd. according to KSK 0412. The tensile strength and elongation at this time mean the tensile strength and elongation at the time of cutting in the S-S curve.

The physical properties measured according to the above method are summarized in Table 1 below.

 division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Moisture content (%) 9 7 5 11 13 Tensile strength (g / d) 6.8 7.0 7.2 6.5 6.2 Shinto (%) 7.5 7.0 6.5 7.5 4.0

As shown in Table 1, when the moisture content of the filament is maintained at 10% or less between the drying step and the winding step according to the manufacturing method of the present invention, It can be seen that the tensile strength and elongation are superior to the lyocell fibers of Examples 1 and 2.

On the other hand, in the case of Comparative Examples 1 and 2, shrinkage and expansion due to water evaporation or the like occur during winding and storage, and may be separated from the paper tube. In addition, since Comparative Examples 1 and 2 cause property deterioration during storage, high-speed running properties and shape stability can be lowered when a tire cord is produced.

The present invention improves the properties and fairness of the yarn such as the strength, elongation and modulus of the yarn by optimizing the moisture content of the filament between the drying step and the winding step in the production of the lyocell filament fiber, A tire cord having excellent productivity can be manufactured.

1 is a partially cutaway perspective view showing a structure of a general tire.

2 is a schematic view illustrating an example of a spinning device for producing lyocell filament fibers according to an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE SYMBOLS

11: Gear pump

12: spinning detention

13: Non-coagulating filament fiber

14: First coagulation bath

15: Second coagulation bath

16: Roller of traction part

17: Flushing device

18: Drying device

19: Winding roll

Claims (7)

Radiating a dope for preparing a lyocell; Solidifying the emitted dope to produce a filament; Washing the filament with water; Drying the washed filament; And And winding the dried filament, And a step of maintaining the water content of the filament at 10% or less between the drying step and the winding step and relaxing the filament. The method according to claim 1, Wherein the relaxation step imparts a relaxation rate of 1 to 5% to the filament by using a difference in advancing speed of the filament in two or more rolls. 3. The method of claim 2, The relaxation process is given a relaxation rate of the filaments in a manner that larger than the filament running speed (V ₂₎ of the second roll equipped with a filament running speed (V ₁₎ of the first roll is first mounted from the two or more rolls are subsequently Wherein the filament yarn is a filament yarn. The method according to claim 1, Wherein the relaxation process is performed by additionally attaching at least one traction roll between the drying step and the winding step. delete delete delete

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