KR101175332B1 - Dope for spinning lyocell, method for preparing lyocell filament fibers therefrom, lyocell filament fibers prepared therefrom, and tire cord comprising the same - Google Patents

Abstract

The present invention is a lyocell spinning dope comprising cellulose, pore-forming material, N-methylmorpholine-N-oxide (NMMO) and water, a method for producing a lyocell filament fiber using the same, It relates to a lyocell filament fiber produced therefrom, and a tire cord comprising the filament fiber.

The lyocell spinning dope of the present invention has an effect of improving elongation by forming a pore in the lyocell filament fiber by removing the pore-forming material in the dope and then spinning it by washing with water.

Tire cord, lyocell, polyethylene glycol

Description

DELOP FOR SPINNING LYOCELL, METHOD FOR PREPARING LYOCELL FILAMENT FIBERS THEREFROM, LYOCELL FILAMENT FIBERS PREPARED THEREFROM , AND TIRE CORD COMPRISING THE SAME}

The present invention relates to a lyocell spinning dope, a method for producing a lyocell filament fiber using the same, a lyocell filament fiber produced therefrom, and a tire cord comprising the same.

The tire is a composite of fiber / steel / rubber and generally has a structure as shown in FIG. 1. In other words, steel and fiber cords serve to reinforce rubber and form a basic skeletal structure in the tire. In other words, compared to the human body is a bone-like role.

The performance required for the cord as a tire reinforcement is fatigue resistance, shear strength, durability, resilience and adhesion to rubber. Therefore, a cord of appropriate material is used according to the performance required for the tire.

Currently commonly used materials for the cord include rayon, nylon, polyester, steel, and aramid, and rayon and polyester are used for body ply (also called carcass) (6 in FIG. 1), and nylon is mainly used. In the cap ply (4 in FIG. 1), and steel and aramid are mainly used for the tire belt portion (5 in FIG. 1).

The following briefly illustrates the tire structure and its characteristics shown in FIG. 1.

Tread (1): This part is to be in contact with the road surface to provide the necessary frictional force for braking and driving, to have good abrasion resistance, to withstand external shocks, and to generate little heat.

Body Ply (or Carcass) (6): A layer of cord inside the tire, which must support loads, withstand impacts, and be resistant to fatigue during rolling.

Belt (5): Located between the body plies, consisting of steel wires in most cases to mitigate external shocks and maintain a wide tread ground to provide excellent driving stability.

Side Wall (3): refers to the rubber layer between the lower part of the shoulder (2) from the bead (9) and serves to protect the body ply (6) inside.

BEAD (9): A square or hexagonal wire bundle with rubber coating on the wire that rests and secures the tire to the rim.

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

CAP PLY (4): A special cord paper placed on the belt of some passenger radial tires that minimizes belt movement when driving.

APEX (8): A triangular rubber filler used to minimize the dispersion of beads, to mitigate external impacts, to protect the beads, and to prevent the ingress of air during molding.

Generally used tire cord material is nylon, polyester, rayon and the like. These materials are limited in size and use, etc. of the tires used due to their advantages and disadvantages.

Nylon fiber has high tensile elongation and high strength, and is mainly used for tires used on curved roads such as heavy trucks and unpaved roads. However, the nylon fiber is not suitable for a tire for a passenger car in which concentrated heat accumulation occurs inside the tire, and a low modulus is used to travel at high speed or require a ride comfort.

Polyester fiber has better shape stability and price competitiveness than nylon, and strength and adhesion are improved due to continuous research, and its usage is increasing in the tire cord field. However, it is not suitable for high-speed running tires because of limitations in heat resistance and adhesive strength.

Rayon fiber, a regenerated cellulose fiber, exhibits excellent strength retention and shape stability at high temperatures. Therefore, rayon fiber is known as an optimal tire cord material. However, due to the strong deterioration due to moisture, thorough moisture management is required during tire manufacturing, and due to the nonuniformity in yarn manufacturing, the rate of defective products is high. Above all, its price / performance ratio is very low compared to other materials, and it is mainly applied only to high speed or expensive tires.

Therefore, in the manufacture of tire cords having excellent high-speed driving properties and shape stability in the related art, research on the improvement of the rigidity and low elongation of the structure of lyocell filament fibers is required.

The present invention is to solve the above problems, it is an object of the present invention to provide a lyocell spinning dope for improving the problem of low elongation of lyocell filament fiber.

It is also an object of the present invention to provide a method for producing lyocell filament fibers using the lyocell spinning dope and lyocell filament fibers produced therefrom.

It is another object of the present invention to provide a tire cord comprising the lyocell filament fibers and having excellent physical properties.

The present invention provides a lyocell spinning dope comprising cellulose, a pore-forming material, N-methylmorpholine-N-oxide (NMMO) and water to achieve the above object.

The present invention also provides lyocell filament fibers and tire cords prepared from the lyocell spinning dope.

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

In the present invention, a filament bundle including a plurality of filament fibers is referred to as a 'multi filament', and a raw cord manufactured by upper and lower edges (or lower and upper edges) of the multifilament is referred to as 'ply twisted yarn', The dip cord treated with the adhesive for tire cord in the twisted yarn is referred to as 'tire cord' .

The lyocell spinning dope according to the present invention includes cellulose, a pore-forming material, N-methylmorpholine-N-oxide (NMMO) and water.

The cellulose may be conventional in the art to which the present invention pertains, but may be used in an amount of 96% or more of alpha-cellulose to improve physical properties of the fiber. In particular, southern pine pulp containing 96% alpha-cellulose can be used.

The lyocell spinning dope of the present invention may include 5 to 35% by weight of cellulose in consideration of spinning properties, and may also be included as 7 to 18% by weight.

In the present invention, the pore-forming material is to form voids in the fiber to obtain the effect of improving the lyocell filament elongation, in consideration of the dope solvent and affinity, such as polyethylene glycol, polybutylene glycol Alkylene glycol can be used.

In particular, the polyalkylene glycol has excellent affinity with the dope solvent, it is maintained in a solid state at room temperature and changes from a high temperature to a liquid phase, so that the polyalkylene glycol is present in the solid phase in the fiber during the lyocell filament fiber manufacturing process and washed at high temperature By eluting in, it is possible to form voids in the fiber and at the same time, a small amount of residual polyethylene glycol serves as a plasticizer to obtain an excellent effect of improving lyocell filament elongation.

For the elongation and excellent strength characteristics of the lyocell filament fibers, the polyalkylene glycol may be a compound having a number average molecular weight of 1,000 to 20,000.

The lyocell spinning dope according to the present invention may include 0.1 wt% or more of the pore-forming material to impart sufficient elongation to the lyocell filament fibers to be manufactured, and to maintain excellent strength characteristics. It may be included in the wt% or less.

In addition, the solvent included in the spinning dope of the present invention is a mixed solvent containing N-methylmorpholine-N-oxide (NMMO): water, the weight ratio of NMMO and water in the mixed solvent is the melting point of the solvent is increased or prepared It may be 93: 7 to 85:15 in order to prevent excessively high temperature and at the same time to ensure the minimum solubility and swelling of the cellulose. The mixed solvent may be included in the dope 60 to 94.9% by weight, but is not necessarily limited thereto.

In the spinning dope of the present invention, after swelling polyethylene glycol and cellulose in a mixed solvent containing N-methylmorpholine-N-oxide (NMMO): water in a weight ratio of 90:10 to 50:50, N-methylmorpholine -N-oxide (NMMO): water by weight ratio of 93: 7 to 85:15, the final content of cellulose is 5 to 35% by weight, more preferably 7 to 18% by weight according to the process for removing water Can be.

In addition, the present invention is spinning, coagulation, washing, and drying the lyocell spinning dope containing cellulose, pore-forming material, N-methylmorpholine-N-oxide (NMMO) and water It provides a method for producing a lyocell filament fiber comprising the step of.

In particular, the method for producing a lyocell filament fiber of the present invention comprises the steps of producing a filament by spinning the spinning dope through a spinning nozzle, the step of solidifying the filament, washing the solidified filament with a washing solution, and It may be prepared according to a manufacturing method comprising the step of drying the washed filament, and the step of removing the pore-forming material using the washing liquid in the washing step.

At this time, the extrusion spinning temperature can be maintained at 70 to 130 ℃.

Solidification of the spun filament is carried out in a coagulation bath, the coagulation temperature may be 45 ℃ or less. This means that the solidification temperature is 45 ° C. or lower so that the temperature is not too high than necessary so that the solidification rate is properly maintained. Here, the coagulation bath is not particularly limited because it can be prepared and used in a conventional composition in the art.

Subsequently, the prepared multifilament is washed with water and dried.

According to the present invention, in consideration of the ease of recovery and reuse of the solvent after washing, NMMO first with a washing liquid, and then in the last step of washing with water to remove the pore-forming material by using water of 30 ℃ to 100 ℃ Can be. At this time, water may be used as the washing liquid, and other additives may be further included if necessary.

The drying temperature of the filament can be adjusted to 90 to 200 ℃, or 100 to 150 ℃. The drying step may be carried out in a one-step drying process, it may also be carried out in a multi-stage drying process to vary the drying process conditions by dividing the interval. Specific drying conditions of each step in the drying step of the multi-stage can be arbitrarily selected as necessary within the above temperature range, in addition to the above conditions, can be used in the technical field to which the present invention belongs.

The lyocell filament fibers of the present invention prepared through the composition and preparation method as described above have an intensity of 5 g / d to 10 g / d and an elongation of 6% to 15%.

On the other hand, the present invention provides a tire cord made from the lyocell filament fibers.

The tire cord of the present invention comprises the lyocell filament fibers. The tire cord may comprise a composite yarn of 2-3 plies having a total number of filaments of 400 to 6000, a total fineness of 400 to 9000 deniers, 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 applications such as body plies or cap plies of pneumatic tires.

Tire cord of the present invention by twisting the lyocell filament fibers to produce a ply twisted yarn of 2 to 3 ply (ply), the twisted yarn is treated with an adhesive solution for tire cord according to a conventional dipping method, and dried and It can be produced by heat treatment.

In addition, the adhesive solution may be a conventional tire cord impregnation solution, preferably a resorcinol-formaldehyde-latex (RFL) adhesive solution may be used.

The cord passing through the adhesive solution is manufactured as a tire cord through a drying process and a heat treatment process. The drying process is carried out with a tension of 20 to 2000 g / cord for 1 minute to 10 minutes at 105 to 160 ℃, the heat treatment process is carried out with a tension of 20 to 2000 g / cord for 1 minute to 10 minutes at 105 to 220 ℃ can do.

In the drying step, moisture existing in the lyocell is dried, and in the heat treatment step, the impregnation solution is reacted to impart adhesion 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 lyocell filament fibers and tire cords made with the lyocell spinning dope of the present invention exhibit excellent elongation 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

The cellulose sheet (buckeye V-81) was put into a grinder equipped with a 100 mesh filter to prepare a cellulose powder having a diameter of 1700 μm or less.

The cellulose powder and polyethylene glycol (PEG) having a number average molecular weight of 1000 were swollen in a 50 wt% NMMO aqueous solution. In this case, the content of cellulose in the NMMO aqueous solution is 6.5% by weight, and the content of polyethylene glycol was added to 0.06% by weight.

The swelled cellulose 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 NMMO aqueous solution. After dissolving the cellulose completely while removing excess moisture, the spinning dope was discharged through the discharge screw. At this time, the cellulose concentration of the discharged spinning dope was 11% by weight, the content of the polyethylene glycol was 0.1% by weight, it was confirmed that the homogeneous state does not contain undissolved cellulose particles.

The cellulose 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 0.047 mm 2. At this time, an air layer of 30 mm was placed between the nozzle and the coagulation bath.

NMMO was removed by spraying a flushing liquid on the discharged and solidified multifilament. In addition, polyethylene glycol was eluted and removed using a 60 ° C washing solution at the last step of the washing process.

After the water washing step, the undried multifilament was dried on a drying roll to obtain a lyocell multifilament yarn.

The dry strength (cutting strength) of the lyocell filament yarn prepared by the above method was 7.0 g / d, and the breaking elongation was 7%.

Example  2

A lyocell filament fiber was prepared in the same manner as in Example 1, except that a spinning dope having a polyethylene glycol content of 1% by weight was used.

The dry strength (cutting strength) of the lyocell filament yarn prepared by the above method was 6.8 g / d, and the cutting elongation was 7.4%.

Example  3

A lyocell filament fiber was prepared in the same manner as in Example 1, except that a spinning dope having a polyethylene glycol content of 5% by weight was used.

The dry strength (cutting strength) of the lyocell filament yarn prepared by the above method was 5.9 g / d, and the breaking elongation was 7.9%.

Example  4

The lyocell filament was used in the same manner as in Example 1 except for using a spinning dope containing 1 wt% of polyethylene glycol having a number average molecular weight of 10000 in the dope, and using a wash solution at 80 ° C. at the end of the washing process. Fibers were prepared.

The dry strength (cutting strength) of the lyocell filament yarn prepared by the above method was 6.2 g / d, and the cutting elongation was 7.5%.

Example  5

The lyocell filament was used in the same manner as in Example 1, except that a dope for spinning containing 1 wt% of polyethyleneglycol having a number average molecular weight of 20000 was used in the dope, and a washing solution at 100 ° C. was used at the end of the washing process. Fibers were prepared.

The dry strength (cutting strength) of the lyocell filament yarn prepared by the above method was 6 g / d, and the cutting elongation was 8%.

Comparative example  One

A lyocell filament fiber was prepared in the same manner as in Example 1 except that polyethylene glycol was not added at the time of dope preparation.

The dry strength (cutting strength) of the lyocell filament yarn prepared by the above method was 7.2 g / d, and the breaking elongation was 6%.

In the above Examples and Comparative Examples, the dry strength and the elongation at break was performed at room temperature using an Instron tensile tester (Model 5566), wherein the crosshead speed was 20 mm / min. Dry strength and elongation values were determined as averages of at least 10 replicates.

The lyocell filament fiber prepared from the lyocell spinning dope according to the present invention is a useful technology that can contribute to industrial development by improving the elongation to produce a high-speed running tire cord.

1 is a partial cutaway perspective view showing a configuration of a general tire.

Claims (10)

delete delete delete delete delete delete Preparing a filament by spinning a spinning dope comprising cellulose, a pore-forming material, N-methylmorpholine-N-oxide (NMMO) and water; Solidifying the filament; Washing the solidified filament with a washing solution having a temperature of 30 to 100 ° C. to remove pore-forming material; And Method for producing a lyocell filament fiber comprising the step of drying the washed filament. delete A lyocell filament fiber made according to claim 7. A tire cord comprising lyocell filament fibers according to claim 9.

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