KR101175334B1 - Process for preparing lyocell filament fiber, lyocell filament fiber, and tire cord - Google Patents

Abstract

The present invention comprises the steps of spinning a lyocell manufacturing dope, solidifying the spinning dope to produce a filament, passing the filament to the traction unit, washing the filament passing through the traction unit in the water washing unit, and It relates to a method for producing a lyocell filament fiber, a lyocell filament fiber, and a tire cord comprising the step of drying the washed filament, the coagulation draft ratio of the filament is 1 or less.

The present invention by effectively controlling the coagulation draft ratio of the filament in the traction and the washing part during the spinning process of the lyocell filament fiber, it is possible to manufacture the lyocell filament fiber having excellent properties and improve the stretching characteristics and processability of the fiber .

Tire cord, lyocell, spinning, towing, flush, solidification draft

Description

Process for producing lyocell filament fiber, lyocell filament fiber, and tire cord {PROCESS FOR PREPARING LYOCELL FILAMENT FIBER, LYOCELL FILAMENT FIBER, AND TIRE CORD}

The present invention relates to a method for producing lyocell filament fibers, lyocell filament fibers, and tire cords.

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.

Commonly used materials for the cord currently include rayon, nylon, polyester, steel, and aramid, and rayon and polyester are used for body plies (also called carcasses) (6 in FIG. 1), and nylon is mainly a cap. In the ply (4 in FIG. 1), and steel and aramid are mainly used in 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 and shape stability in the related art, a study on improving the rigidity and low elongation of the structure of lyocell filament fibers is required.

The present invention is to provide a method for producing a lyocell filament fiber to improve the stretching properties and processability of the lyocell filament fiber.

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

The present invention comprises the steps of spinning dope for lyocell manufacturing; Solidifying the spun dope to produce a filament; Passing the filament through a traction; Washing the filament passing through the towing unit in a water washing unit; And drying the washed filaments and providing a method for producing lyocell filament fibers having a coagulation draft ratio of the filament represented by the following Formula 1 being 1 or less:

[Equation 1]

Coagulation Draft Ratio = V ₂ / V ₁

In the formula, V ₁ is the traveling speed of the filament coming out of the traction, and V ₂ is the traveling speed of the filament entering the water washing.

The present invention also provides lyocell filament fibers having an elongation at break of 6-15%.

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

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

The lyocell filament fibers to be developed in the present invention have optimal properties for use in the use of tire cords, and in particular, have improved characteristics in elongation and strength.

The present inventors effectively control the coagulation draft ratio of the filament passing through the traction part in the pre-washing step of the lyocell filament spinning process, ensuring the excellent spinning stability and can produce a lyocell filament fiber having excellent elongation and modulus It has been found and the present invention has been completed.

Figure 2 is a schematic diagram showing an example of a spinning device for producing a lyocell filament fiber according to an embodiment of the present invention. Referring to the configuration of Figure 2, the general type lyocell multifilament manufacturing apparatus is a gear pump 11 for supplying a spinning spinning stock solution at a constant pressure, spinning spinning spinning spinning stock solution supplied from the extruder in the form of fibers A first coagulation bath 14 for solidifying the mold 12 and the uncoagulated fiber 13 discharged from the spinneret may be provided, and a second coagulation bath 15 may be further provided if necessary. The filament having passed through the coagulation baths 14 and 15 moves to the water washing part by driving the traction part 16, and removes the solvent from the water washing part 17. Subsequently, the filament washed with the washing part may be dried in the drying part 18 and then wound to obtain a final lyocell filament.

3 is an enlarged view illustrating a towing unit 16 and a water washing unit 17 according to an embodiment of the present invention, and a filament traveling speed V ₁ and the water washing unit in the towing unit 16. The coagulation draft ratio can be adjusted by adjusting the filament traveling speed (V ₂ ) in (17).

The present invention is characterized in that the coagulation draft ratio of the filament represented by the following formula 1 between the traction unit 16 and the water washing unit 17 is adjusted to 1 or less, the elongation and modulus to the final lyocell filament fibers Can give an improvement:

[Equation 1]

Coagulation Draft Ratio = V ₂ / V ₁

In the formula, V ₁ is the traveling speed of the filament coming out of the traction, and V ₂ is the traveling speed of the filament entering the water washing.

In the present invention, the traveling speed (V ₁ ) of the filament coming out of the traction unit 16 is more specifically, the running speed of the filament in the final last traction roll of the traction unit 16 before applying the solidified filament to the washing process , The traveling speed (V ₂ ) of the filament entering the water washing unit 17 is more specifically the running speed of the filament in the first washing roll applying the filament passed through the towing unit 16 in the washing process.

The coagulation draft ratio of the present invention can be adjusted to 1 or less, preferably 0.8 to 0.99, more preferably 0.95 to 0.99. If the coagulation draft ratio exceeds 1, sufficient elongation cannot be imparted to the lyocell filament fibers.

For the lyocell manufacturing dope in the present invention, any spinning stock solution commonly used in the lyocell filament fiber manufacturing process may be used, such as cellulose, N-methylmorpholine-N-oxide (N-methylmorpholine-N-oxide; NMMO) and spinning stock containing water may be used.

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

The spinning process using the spinning stock solution can be carried out according to a generally known method, except for the step of spraying the coagulating liquid in the bottom of the coagulation bath, preferably spinning dope at a temperature in the range of 80 ℃ to 130 ℃ Spinning, cooling the non-coagulated fiber through the air gap section, a coagulating solution section for solidifying the cooled uncoagulated fiber, and a washing section for removing residual N-methylmorpholine-N-oxide (NMMO) from the coagulated fiber. And, after passing the drying section, it is preferable to include the step of winding up.

Solidification of the filament spun through the spinneret in the present invention is carried out by passing through the air gap section to the coagulation solution, in terms of controlling the coagulation rate of the filament, the temperature of the coagulation solution is -20 ℃ to 30 ℃, preferably May be performed at 0 ° C to 30 ° C.

In addition, the coagulating solution in the present invention is not particularly limited because it can be prepared and used in the conventional composition in the art, preferably N-methylmorpholine-N-oxide (N-methylmorpholine-N-oxide: NMMO ) And NMMO aqueous solution containing water may be used, and the concentration of NMMO in the coagulation solution may be 5% by weight or more, in order to optimize the coagulation draft ratio in the pre-washing step, 5 to 30% by weight of NMMO aqueous solution may be used. .

In addition, in the present invention, after passing the filament through the coagulation solution, the process may be carried out without additional coagulation bath, and if necessary, after passing the filament through the first coagulation solution as shown in FIG. It may further comprise the step of further passing through the coagulating solution.

Subsequently, the prepared lyocell filament is passed through a towing unit, followed by washing and drying.

The filament that has passed through the coagulation bath has a state in which the internal structure is not fixed yet, and in this state, by adjusting the coagulation draft ratio represented by the formula 1 as described above, the elongation of the fiber can be adjusted to the optimum range.

According to the present invention, in consideration of the ease of recovery and reuse of the solvent after washing, NMMO can be removed with a washing solution. At this time, water may be used as the washing liquid, and other additives may be further included if necessary.

The filament fibers thus obtained can be carried out by adjusting to a temperature of 90 to 200 ℃, or 100 to 150 ℃ in the drying step. 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 by varying 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 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 have a tensile strength of 5 g / d or more, preferably 6 g / d or more, more preferably 6 to 9 g / d, and a single yarn fineness variation of 2% or less, and total fineness. 200 to 3000 denier, cutting strength and cutting elongation fluctuation (CV%) is 8% or less, uniformity (U%) is 3% or less, more preferably 2.5% or less, and cutting elongation is 6-15%. Such lyocell fibers can be used as industrial fibers, such as tire cord materials.

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 deep cord treated with the adhesive for the tire cord in the twisted yarn is referred to as 'tire cord' or 'code'.

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, the twisted yarn is treated with an adhesive solution for the tire cord according to a conventional dipping method, and dried And 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 manufacturing process of the present invention can secure excellent spinning stability and improve spinning performance by adjusting the coagulation draft ratio to the filament passing the coagulation bath in the pre-washing step, and the lyocell filament fiber and tire cord of the present invention Excellent elongation and strength properties.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

Example  One

A pulp with a degree of polymerization (DPw) of 1,200 and 97% of α-cellulose is mixed with an NMMO / H ₂ 0 mixed solvent (weight ratio 90/10) having a propylgallate content of 0.01% by weight, to prepare a lyocell dope having a concentration of 11% by weight. Prepared.

The lyocell dope was spun, coagulated, washed with water and dried using a spinning device based on the configuration as shown in FIG. 2 to prepare lyocell filament fibers.

The production dope was maintained at a spinning temperature of 110 ℃ in the spinning nozzle of the spinneret (12), spinning by adjusting the discharge amount and spinning speed so that the final filament fineness is 1,650 denier.

The uncoagulated fiber 13 discharged from the spinning nozzle was spun into the coagulation baths 14 and 15, and the coagulating solution was used at a temperature of 25 ° C., at a concentration of 85% by weight of water and 15% by weight of NMMO. At this time, the coagulant concentration of the coagulation bath was continuously monitored using a sensor and a refractometer.

The filament passed through the coagulation solution was passed through the towing unit 16 based on the configuration as shown in FIG. At this time, the solidification draft ratio (V ₂ / V ₁ ) of the traveling speed (V ₁ ) of the filament in the last roll of the tow portion 16 and the traveling speed (V ₂ ) of the filament in the first flush roll of the water washing unit (17) ) Is 0.99.

Subsequently, the filaments were removed with NMMO using water in the washing device 17, and dried in the drying device 18 and then wound to prepare lyocell filament fibers.

Example  2

Example 1 except that the coagulation draft ratio (V ₂ / V ₁ ) of the filament running speed (V ₂ ) in the water washing unit in the traction unit 16 compared to the traveling speed (V ₁ ) of the filament The same procedure was repeated to produce lyocell filament fibers.

Example  3

Example 1 except that the coagulation draft ratio (V ₂ / V ₁ ) of the filament running speed (V ₂ ) to the filament running water (V ₁ ) in the traction unit 16 is 0.95 The same procedure was repeated to produce lyocell filament fibers.

Comparative example  One

The lyocell filament fibers were prepared by repeating the same procedure as in Example 1 except that the filament speeds of the tow portion 16 and the flush portion 17 were the same.

The physical properties of the lyocell-doped dope and filament fiber prepared according to Examples 1 to 3 and Comparative Example 1 were evaluated by the following method.

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

The test piece was dried at 110 ° C for 2 hours, preliminarily dried below the process moisture content, and then left at the standard state (25 ° C, 65RH%) of KSK 0901 (fiber test room) for at least 24 hours to reach a water equilibrium state. Then, it dried at 105 degreeC for 2 hours.

The dried test piece was measured according to the KSK 0412 standard at a sample length of 250 mm and a tensile speed of 300 m / min using an Instron low speed tensile tester. Physical properties measured according to the above method are summarized in Table 1 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Cutting strength (g / d) 6.8 6.7 6.5 6.8 Elongation at break (%) 6.4 7.1 7.5 5.6

As shown in Table 1, the lyocell fiber prepared by adjusting the coagulation draft ratio in the pre-washing step according to the manufacturing method of the present invention can be seen that the elongation is superior to the lyocell fiber of Comparative Example 1.

The present invention ensures excellent post-treatment (washing and drying) stability by effectively controlling the coagulation draft ratio of the traction part and the water washing part during the spinning process of the lyocell filament fiber, and the properties and processability of the fiber such as elongation and modulus of the fiber. It can be improved to produce a lyocell yarn filament having excellent physical properties.

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

Figure 2 is a schematic diagram showing an example of a spinning device for producing a lyocell filament fiber according to an embodiment of the present invention.

3 is an enlarged view illustrating a towing unit and a water washing unit in the radiation device of FIG. 2;

Claims (6)

Spinning dope for lyocell manufacturing; Solidifying the spun dope to produce a filament; Passing the filament through a traction; Washing the filament passing through the towing unit in a water washing unit; And Drying the washed filaments / RTI > Method for producing a lyocell filament fiber having a coagulation draft ratio of filament represented by the following Formula 1 is 1 or less: [Equation 1] Coagulation Draft Ratio = V ₂ / V ₁ Where V ₁ is the traveling speed of the filament coming out of the towing section and V ₂ is the traveling speed of the filament entering the flush section. The method of claim 1, The method for producing a lyocell filament fiber of the coagulation draft ratio is 0.8 to 0.99. The method of claim 1, The method of producing a lyocell filament fiber is to use a coagulation bath having a concentration of 5 to 30% by weight of NMMO in the coagulation step. delete delete delete

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