KR100522549B1 - High tenacity lyocell tire cord and tire producted by the same - Google Patents

Abstract

The present invention relates to a tire cord using a high-strength lyocell filament and a method for manufacturing a tire. More specifically, i) N-methyl morpholine N-oxide (hereinafter referred to as NMMO) / water mixed solvent for cellulose and PVA mixed powder Dissolving in to prepare a spinning solution (Dope); ii) an orifice having a diameter of 100 to 300 µm and a length of 200 to 2,400 µm, the spinneret including an orifice having a ratio of diameter to length (L / D) of 2 to 8 times and an interval between 2.0 and 5.0 mm between orifices; Extruding the spinning stock solution through the fibrous spinning stock solution to allow the fibrous spinning stock solution to pass through an air layer to reach a conical upper coagulation bath, and then coagulate to obtain a multifilament; iii) introducing the obtained multifilament back into the lower coagulation bath, changing the direction of travel thereof, and introducing it into a water washing bath to wash it; And iv) winding and drying the multifilament washed with water, and v) twisting the wound yarn with a twister to produce a raw cord, and then weaving it to immerse it in a dipping liquid. It relates to a manufacturing method of.

   The lyocell tire cord manufactured using the lyocell filament manufactured as described above has an elongation at specific load of 14.0 to 35.0 kg, a total denier 3000 to 6000 denier, a twist constant of 0.30-0.95, and a tensile load of 4.5 kg. As the sum of load and dry heat shrinkage (ES) is 1.0 to 4.0, and the adhesive strength to rubber is 8.0 to 15.0 kg, the elongation is low and the strength and modulus are excellent. It is characterized by providing a tire.

Description

High tenacity lyocell tire cord and tire producted by the same}

The present invention relates to a tire cord using a high-strength lyocell filament and a method for manufacturing a tire. More specifically, i) a cellulose and PVA mixed powder is used as an N-methylmorpholine N-oxide (hereinafter referred to as NMMO) / water mixed solvent. Dissolving in to prepare a spinning solution (Dope); ii) an orifice having a diameter of 100 to 300 μm and a length of 200 to 2,400 μm, including several orifices having a ratio of diameter to length (L / D) of 2 to 8 times and an interval between orifices of 2.0 to 5.0 mm Extruding the spinning stock solution through a nozzle to allow the fibrous spinning stock to pass through an air layer to reach a conical top coagulation bath, and then coagulate to obtain a multifilament; iii) introducing the obtained multifilament back into the lower coagulation bath, changing the direction of travel thereof, and introducing it into a water washing bath to wash it; And iv) winding and drying the multifilament washed with water, and v) twisting the wound yarn with a twister to produce a raw cord, and then weaving it to immerse it in a dipping liquid. It relates to a manufacturing method of.

Tire cords, which are used as the skeleton inside a tire, are currently used in various materials, including polyester cords, nylon cords, aramid cords, rayon cords, and steel cords.The essential basic performance of these cord materials is (1 ) High strength and initial modulus (2) Heat resistance, not brittle in dry and wet heat (3) Fatigue resistance (4) Form stability (5) Excellent adhesion to rubber, etc. Reference: Fukuyuan (纖維 and 工業, 1980 Vol. 36, pp 290) However, all currently known tire cords do not satisfy all of the above-mentioned various functions. It is used.

For example, in the case of high-speed radial tires for passenger cars, which require initial modulus, heat resistance, and shape stability among the above-mentioned performances, tires made of rayon fibers having low shrinkage and excellent shape stability due to the intrinsic properties of the fibers themselves Code is mainly used. Initial modulus is expressed as the slope of the load to produce a level of elongation, which is the slope of the elongation-load curve in the elongation test. Tires with a large modulus tire cord have less tire deformation under a certain level of load, resulting in improved tire fatigue performance, heat generation, and durability. This results in improved steering stability. Particularly, in the case of the rayon cord, since there is almost no physical property deterioration in the range of the actual tire running temperature (80 to 100 ° C.), excellent steering stability is shown compared to other cord materials for passenger car tires.

However, in case of the existing rayon tire cord, the strength is somewhat low and the modulus deterioration due to moisture absorption is severe, which makes it difficult to control water and process during tire production, and also moisture penetrates due to damage to the surface of the tire even after the tire is produced. In this case, there are disadvantages such as deterioration of tire performance due to a decrease in strength and modulus. Therefore, not only the strength is excellent, but also the strength and modulus that can be maintained at the time of moisture absorption that may occur in the production process is required.

On the other hand, lyocell fiber, which is an artificial fiber made of cellulose, has low elongation, high strength, excellent morphological stability, and low moisture content, so that the strong retention rate is more than 80% even when wet. Therefore, it has a merit of lowering the change in shape while having a relatively strong deterioration than rayon (60%), and may be considered as an alternative to the above requirement, but as described below, the radiation to the tire cord is still a problem. Until now, tire cords that use them do not exist.

Textiles used in tire cords or industrial materials sectors differ in the fields of apparel where color expression and handling are important, and the physical properties of fibers such as strength and modulus determine their value.

In accordance with this trend, fiber makers continue to improve fiber quality by utilizing various fiber manufacturing techniques to maximize the physical properties of the fiber. Among various methods for improving fiber properties, when the polymer has a structure oriented along the fiber axis, it is possible to provide a fiber having good properties for clothing and industrial use. In most cases, the orientation is achieved by stretching, and the stretching step has the greatest influence on the mechanical properties of the fibers.

In the case of melt spinning, stretching is carried out in a thermoplastic state with good fluidity of the molecule. In the case of solution spinning, a solution consisting of a solvent, a non-solvent, and a polymer three component may be prepared, and then wet or dry spinning may be used. In the case of dry spinning, stretching may be performed while the solvent is evaporated. In the case of wet spinning, stretching is mainly performed in the process of solidification based on the coagulation solution concentration and temperature.

On the other hand, the spinning solution consisting of three components of NMMO / water / cellulose commonly used for the production of lyocell fiber is a high temperature in the range of 80 to 130 ℃, so as to immerse the spinning nozzle in a coagulation bath to spin it, as in general wet spinning Due to the rapid solidification, it is difficult to secure sufficient stretching performance and physical properties, and high viscosity cellulose solution of about 10,000 poise is difficult to expect solvent evaporation only by dry spinning.

On the other hand, there is a wet and dry spinning method as a technique to improve the physical properties and radioactivity by utilizing the air gap (hereinafter, the air layer) between the spinning nozzle and the solidification bath interface to the maximum.

For example, EP-A-259,672 discloses an aesthetic improvement by a method of drawing and solidifying through an air layer when preparing aramid fibers, and US Pat. No. 4,501,886 spins cellulose triacetate using an air layer. It is starting to do. In addition, Mitsubishi Rayon's Japanese Patent No. 81,723 discloses high-speed spinning of PAN fibers using an air layer, while East German Patent No. 218,124 uses filament adhesion in spinning cellulose solution using a tertiary amine oxide-based aqueous solution. In order to prevent the use of the air layer is disclosed, US Patent No. 4,261,943 discloses spraying non-solvent water in the air layer in the range of 50 ~ 300mm to prevent the adhesion of the filaments.

The above technique can increase the orientation of the fiber spun by utilizing the air layer, but when applied directly to the production of lyocell multifilament for tire cords, there is an unstable process such as filament mutual adhesion due to the increase in the number of filaments It is difficult to realize satisfactory spinning workability, and in particular, lyocell fibers obtained by the above methods exhibit strength and elongation not suitable for use as tire cords in terms of physical properties.

In addition, H. Chanzy et al. (Polymer, 1990 Vol. 31, pp 400-405) added a salt such as ammonium chloride or calcium chloride to NMMO in a solution of DP 5,000 in cellulose. After spinning, a fiber having a strength of 56.7 cN / tex and an elongation at break of 4% was produced, but it is difficult to commercialize due to the problem of recovering the coagulant added with salt.

According to U.S. Patent 5,942,327, a fiber having a single yarn fineness of 1.5 dtex having a strength of 50 to 80 cN / tex and an elongation of 6 to 25% was prepared by performing air layer spinning with a solution in which cellulose of DP 1,360 was dissolved in NMMO hydrate. Only 50 strands. Considering the fact that a tire cord filament is usually made of several hundred strands of filament to be around 1,500 denier, it is determined that it is difficult to secure the required physical properties of the tire cord after twisting and dipping. Actually, in spinning of fibers, it is more difficult to control cooling, drying, and washing conditions of fibers during spinning of denier fibers than spinning of denden fibers. Therefore, it is possible to express more than a certain level of physical properties and overall uniformity of the filaments. Since it is difficult, it is difficult to apply it to industrial companies simply referring to the fiber properties of about 50 strands. In addition, since the process stability and cooling efficiency for the adhesion of the filaments discharged to the spinning nozzle vary with the increase in the number of filaments, the outer diameter of the spinning nozzle, the orifice diameter, the orifice spacing, the air bed length, the cooling air supply condition, and the coagulating liquid. A new design is needed to consider the drying conditions according to the direction of travel and the spinning speed, which can lead to the difference in properties.

In U.S. Patent 5,252,284, the number of filaments is 800 to 1,900, but it was radiated under the condition of short air layer within 10mm and winding speed of 45m / min. As a result of low stretching orientation, the elongation was 15.4%. / tex is difficult to use as a tire cord yarn in terms of strength and productivity.

In addition, the following techniques are known in the conventional method for producing a solution of cellulose and a polymer mixture using an NMMO solvent.

US Patent No. 3447939 proposes a method for preparing a solution in which cellulose and polyvinyl alcohol are dissolved in NMMO. US Patent No. 3508941 proposes a method for dissolving cellulose and polyvinyl alcohol mixture in NMMO. U.S. Patent No. 4255300 discloses excellent fiber elongation when the composition ratio of cellulose and polyvinyl alcohol is 4: 1 to 2: 1 and the ratio of polymer to solvent is 20% or less, but polyvinyl alcohol is added to cellulose. It is not disclosed that the strength of the fiber is thereby improved.

In addition, U.S. Patent No. 6245837 suggests that a mixture of cellulose and polyethylene, polyethylene glycol, polymethylmethacrylate, polyacrylamide, and the like can be dissolved in NMMO solution to produce a fiber having a strength of 27 cN / tex. The disadvantage is that the strength is low for use in industrial or tire cords.

Therefore, it can be said that the cellulose solution for producing high strength cellulose fibers is still required by solving the problems of the prior art.

In response to these demands, the present inventors can produce fibrillated cellulose fibers when cellulose / polyvinyl alcohol / NMMO solution is formed by spinning method and produce cellulose fibers with excellent flexibility and particularly high strength, for industrial or tire cords. It was found to be suitable and came to complete the present invention.

The present inventors solved the above problem and produced a lyocell yarn of the type that can be used as a tire cord as follows. As a spinning stock solution, cellulose and PVA mixed powders were dissolved in N-methylmorpholine N-oxide (hereinafter, NMMO) / water mixed solvent to prepare a spinning stock solution (Dope), and the spinning stock solution was extruded through an orifice having a specific structure. After the fibrous spinning stock reaches the conical upper coagulation bath, it solidifies to obtain multifilament, and the multifilament obtained is introduced into the lower coagulation bath again, and the direction of travel thereof is changed to wash water. Introduced in water, washed with water, and dried and emulsified by washing the multi-filament is washed with water, it was confirmed that the lyocell multi-filament for tire cords with excellent physical properties can be produced and led to the present invention. The present invention provides a tire cord and a lyocell yarn with excellent strength and modulus, which can provide a tire cord having improved steering stability, shape stability, and uniformity using a lyocell multifilament manufactured as described above. It is to provide a method for producing with high productivity.

The present invention for achieving the above object is i) dissolving cellulose and PVA mixed powder in N-methyl morpholine N-oxide (hereinafter NMMO) / water mixed solvent to prepare a spinning stock solution (Dope); ii) an orifice having a diameter of 100 to 300 μm and a length of 200 to 2,400 μm, including several orifices having a ratio of diameter to length (L / D) of 2 to 8 times and an interval between orifices of 2.0 to 5.0 mm Extruding the spinning stock solution through a nozzle to allow the fibrous spinning stock to pass through an air layer to reach a conical top coagulation bath, and then coagulate to obtain a multifilament; iii) introducing the obtained multifilament back into the lower coagulation bath, changing the direction of travel thereof, and introducing it into a water washing bath to wash it; And iv) winding and drying the multifilament washed with water, and v) twisting the wound yarn with a twister to produce a raw cord, and then weaving it to immerse it in a dipping liquid. It relates to a manufacturing method of.

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

In the method according to the present invention, in step iii), a cellulose and PVA mixed powder is dissolved in an N-methylmorpholine N-oxide (hereinafter, NMMO) / water mixed solvent to prepare a spinning stock solution (Dope).

In order to manufacture the lyocell multifilament for tire cords according to the present invention, pulp having high purity of cellulose should be used. In general, lignin is known to have an amorphous structure and hemicellulose (hemicelluose) has a low crystalline structure, so in order to manufacture high quality cellulose fibers, it is preferable to minimize these components and use a high α-cellulose content. By using high cellulose molecules with high orientation structure and high crystallization, excellent physical properties can be expected. Preferably, DP 800 or 1,200, soft wood pulp (soft wood pulp) of 93% or more α-cellulose content is used.

In order to manufacture the lyocell multifilament for tire cords according to the present invention, polyvinyl alcohol (PVA) is added to cellulose in order to improve fibril resistance of lyocell fibers and to improve flexibility and strength to prepare spinning stock solutions. In addition, polyvinyl alcohol serves to increase the fluidity of the solution by lowering the viscosity of the cellulose solution to increase the uniformity of the solution. By producing a highly homogeneous cellulose solution, the spinning property can be improved and a filament excellent in physical properties can be produced.

In the method according to the present invention, N-methylmorpholine N-oxide (NMMO) / water mixed solvent is used as a solvent in the spinning stock solution, NMMO is a water content in the range of 10 to 20 wt%, more preferably 13 NMMO hydrate adjusted to wt% is used.

In the method according to the present invention, preparing a high homogeneous high concentration spinning stock solution by increasing the penetration of the solvent is an essential element for producing a fiber having excellent physical properties, for this purpose, a device capable of imparting high shear stress is required. Appropriate dissolution temperatures in the range of 80 to 130 ° C. should be formed. If the melting temperature is higher than 130 ℃, there is a disadvantage that the molecular chain end groups increase due to the molecular weight decrease by the thermal decomposition of cellulose, which lowers the mechanical properties and disadvantages that cause the decomposition of NMMO, if less than 80 ℃ required for sufficient dissolution There are disadvantages of increasing the time and energy to be prepared and producing a low concentration of cellulose solution.

In addition, in order to prepare a homogeneous spinning solution containing no cellulose particles undissolved, a step of uniformly mixing the cellulose / PVA mixed powder with the liquid NMMO prior to the dissolution process and then infiltrating the liquid NMMO into the inside of the cellulose powder must be swelled. need.

The method for preparing a homogeneous cellulose solution for this purpose is to inject powdered cellulose mixed with polyvinyl alcohol into a kneader with concentrated liquid NMMO, and then mix it in the kneader to disperse, shear, compress, tension, The superposition is repeated, and then the swollen cellulose / PVA mixed powder is pasted and dissolved by continuous injection into the extruder connected to the kneader. It is possible to produce a highly homogeneous cellulose / PVA spinning stock solution as described above.

More specifically, the cellulose is mixed in a powder mixer with a cellulose powder having a mean particle size (average size of cellulose particles) of 500 μm or less and a polyvinyl alcohol powder having a polymerization degree of 1,000 to 4,000. The content of polyvinyl alcohol in the cellulose / polyvinyl alcohol mixed powder is 0.5 to 30% by weight, more preferably 1 to 10% by weight. When the content of the polyvinyl alcohol is less than 0.5% by weight, it does not contribute to not only fibrillation resistance but also physical property improvement, and when the content of the polyvinyl alcohol is greater than 30% by weight, elution occurs in the coagulation bath after spinning, which increases the recovery cost of NMMO. .

In more detail, the spinning stock solution is prepared by concentrating a 50 wt% NMMO aqueous solution in a conventional manner to lower the water content to 10 to 20 wt%, which is simultaneously injected into the kneader together with the cellulose / PVA powder. Here, NMMO is used to swell the cellulose / polyvinyl alcohol mixed powder in the kneader, so that the NMMO temperature during transport to the kneader is maintained at 70 to 100 ° C, more preferably at 80 to 90 ° C. The prepared cellulose / polyvinyl alcohol powder and the concentrated NMMO solution were injected into a kneader maintained at 65 to 90 ° C., more preferably 75 to 80 ° C., and the cellulose / polyvinyl alcohol mixed powder content for NMMO was determined by the degree of polymerization of the cellulose polymer. According to the final concentration of 5 to 20% by weight, more preferably 9 to 14% by weight. The injected cellulose / polyvinyl alcohol powder and liquid NMMO produce uniformly dispersed cellulose / polyvinyl alcohol paste through repeated compression, tension, overlap, and shearing processes in the kneader. Maintain at 80 ° C. Spinning stock solution is prepared by dissolving the cellulose / polyvinyl alcohol paste forcedly transferred to the extruder at a predetermined speed at 85 to 105 ° C.

In step ii) of the method according to the present invention, an orifice having a diameter of 100 to 300 µm and a length of 200 to 2.400 µm, wherein the ratio (L / D) of the diameter to the length is 2 to 8 times and the spacing between the orifices is 2.0 to The spinning stock solution is extruded through a spinning nozzle including a plurality of orifices of 5.0 mm, so that the fibrous spinning stock passes through the air layer to reach a conical upper coagulation bath, and then coagulates to obtain a multifilament.

FIG. 1 schematically shows a spinning process according to the present invention. When the cellulose solution is quantitatively supplied from the gear pump 1 in FIG. 1, the radiation source solution extracted through the spinning nozzle 2 is an air layer in a vertical direction. Pass 3) to reach the interface of the coagulating solution. The spinning nozzle 2 used is usually circular in shape, having a nozzle diameter of 50 to 160 mm, more preferably 80 to 130 mm. If the nozzle diameter is less than 50mm, the distance between the orifices is too short, which reduces the cooling efficiency of the solution and may cause adhesion before the discharged solution solidifies. If the nozzle diameter is too large, peripheral devices such as the spinning pack and the nozzle may become large, which is disadvantageous in terms of equipment. . In addition, if the diameter of the nozzle orifice is less than 100 μm, a large number of trimmings occur during spinning, which adversely affects radioactivity. If the nozzle orifice exceeds 300 μm, the solidification rate of the solution in the coagulation bath after spinning becomes slow. Defensive becomes difficult. In addition, if the length of the nozzle orifice is less than 200㎛ bad orientation of the solution is bad physical properties, if it exceeds 2,400㎛ there is a disadvantage that excessive cost and effort in the manufacture of the nozzle orifice.

Considering the tire cord and the industrial in terms of use, in consideration of the orifice spacing for uniform cooling of the solution, the number of orifices is 500 to 1,500, more preferably 800 to 1,200. Until now, the development of industrial lyocell fibers has been attempted, but there have been no reports on the development of high strength filaments such as tire cords, because the more the number of filaments radiated, the greater the impact on radioactivity and high spinning technology is required. In order to solve this problem, the present invention employs a spinneret 2 including an orifice that satisfies the above-described specific condition within the above range. If the number of orifices is less than 500, the fineness of each filament becomes thick, so that NMMO is not sufficiently released in a short time, so that solidification and washing are not completed. If the number of orifices is more than 1,500, it is easy to produce close filaments and close-ups in the air layer section, and the stability of each filament decreases after spinning. Can cause.

When the fibrous spinning stock solution passing through the spinning nozzle 2 solidifies in the upper coagulating solution, the larger the diameter of the fluid, the greater the difference in the coagulation rate between the surface and the inside, so that it is difficult to obtain a dense and uniform fiber. It gets hard. Therefore, even when the cellulose solution is spun, the same discharge amount can be obtained into the coagulating solution with a smaller diameter by maintaining the appropriate air layer 3. Too short air gap distances increase the rate of micropores generated during rapid surface layer solidification and desolvation, which hinders the increase in elongation ratio, while too long air gap distances are associated with the effects of filament adhesion, ambient temperature, and humidity. It is difficult to maintain process stability by receiving a lot. The air layer is preferably 20 to 300 mm, more preferably 30 to 200 mm.

When passing through the air layer (3), the filament is cooled and solidified to prevent fusion and at the same time to supply cooling air to increase the penetration resistance to the coagulating liquid, to supply the cooling air to grasp the atmosphere of the air layer (3) A sensor 5 is attached between the inlet of the device 6 and the filament to monitor temperature and humidity to adjust the temperature and humidity. In general, the temperature of the supplied air is maintained in the range of 5 ℃ to 20 ℃. If the temperature is less than 5 ° C is filament solidification is accelerated to disadvantage the high-speed spinning, if the temperature is higher than 20 ° C, the penetration resistance to the coagulation liquid interface is poor, and trimming may occur.

In addition, the moisture content in the air is an important factor that can affect the filament coagulation process, the relative humidity in the air layer (3) should be adjusted to RH 10% to RH 50%. More specifically, RH 10% to 30% of dried air near the nozzle and RH 30% to 50% of wet air near the coagulating liquid improve stability in terms of filament solidification rate and fusion of the spinneret surface. Can be. Cooling air is blown horizontally on the side of the filament discharged vertically, the wind speed is advantageously in the range of 1 to 10 m / sec, more preferably in the range of 2 to 7 m / sec. If the wind speed is too low, the cooling air cannot prevent other atmospheric conditions around the filament discharged to the air layer and cause the difference of solidification rate and trimming of the filament where the cooling air reaches the latest on the spinning nozzle, making it difficult to produce uniform filament. If too high, the filament yarn shakes, causing the risk of sticking and impeding uniform coagulating fluid flow, thus impairing the radiostability.

The composition of the upper coagulation bath used in the present invention is such that the concentration of the NMMO aqueous solution is 5-20%.

When the filament passes through the upper coagulation bath 4, if the spinning speed increases by 50 m / min or more, the shaking of the coagulation solution is severed by friction between the filament and the coagulation solution. In order to improve productivity by extending the excellent physical properties and spinning speed through the stretching orientation, such a phenomenon is a factor that impairs process stability, it is necessary to minimize it. Therefore, a donut-shaped mesh network 7 is installed on the surface 4 of the upper coagulation bath, and the coagulation bath is designed to flow the coagulating liquid downward in the same direction as the filament traveling direction, so that the stretching orientation is naturally Allow it to proceed.

In the step iii) of the method according to the invention, the obtained multifilament is introduced again into the lower coagulation bath 8, the direction of travel thereof is introduced into the water washing bath, and the lower coagulation bath 8 is the upper coagulation bath ( In 4), the coagulating liquid 10 flowing down along with the filament is collected, and a roller 9 for converting in the horizontal direction is installed inside the lower coagulation bath 8. The roller 9 is rotated to reduce the frictional resistance. The concentrations of the upper coagulation bath 4 and the lower coagulation bath 4 are the same by setting up and circulating a control bath separately so that the concentrations of the upper coagulation bath 4 and the coagulation liquid are the same or within 0.5%. Or within 0.5%. As the filament passes through the upper coagulation bath (4) and the lower coagulation bath (8), the desolvent and the stretching are performed at the same time, which has a great influence on the formation of physical properties. The filament that has passed through the lower coagulation bath 8 is washed in the washing bath. The washing method follows a conventional method known in the art.

In the step iii) of the method according to the invention, the multifilament having been washed with water is dried and wound by winding. Drying, tanning and winding processes are in accordance with known conventional methods. After drying and winding process, it is supplied as tire cord and industrial filament yarn.

The cellulose fibers produced by the process according to the invention are lyocell multifilaments with a total denier range of 1,000 to 2,500 and a cutting load of 9.0 to 15.0 kg. The multifilament is composed of 500 to 1500 individual filaments having a fineness of 0.5 to 4.0 denier.

The present invention overcomes the limitation of wet spinning of the lyocell multifilament by the method as described above when lyocell filament spinning, when the method according to the invention, the spinning speed can be up to 250m / min. That is, according to the present invention, in spite of the large number of orifices of the nozzles, not only a homogeneous cellulose solution is produced, but also cooling air of appropriate temperature and humidity is improved to improve radioactivity and to minimize friction generated in the coagulation bath. High speed spinning can be achieved.

In step v) of the method according to the present invention, the wound yarn is twisted with a twister to produce a raw cord, and then weaved and immersed in a dipping liquid to provide a tire cord and a tire.

When explaining the twisting process of the present invention in more detail, the lyocell multifilament manufactured by the above method is to twist the two wound yarns with a direct twisting machine in which the twisting and joining is carried out at the same time 'raw cord (Raw Cord) for the tire cord Manufacture. Raw cords are manufactured by adding Ply Twist to the lyocell yarn for tire cords and then adding them together with Cable Twist. In general, the upper and lower ends are subjected to the same or different years as needed.

An important result of the present invention is that the physical properties of the cord, such as elongation, mesophilic, fatigue resistance, depending on the level (twist) of the twist applied to the lyocell multifilament. In general, when the twist is high, the strength decreases, and the trunk and the body tend to increase. The fatigue fatigue tends to improve with the increase of twist. The soft water of the lyocell tire cord manufactured in the present invention was manufactured at 300/300 TPM to 500/500 TPM at the same time as the upper and lower edges, and giving the same upper and lower edges to the same value does not indicate rotation or twist. It is for maximizing physical expression by making it easy to maintain a straight line, without. At this time, if less than 300/300 TPM, the extension of the raw cord is reduced and fatigue fatigue is easy to fall, and if it exceeds 500/500 TPM, the strength is largely unsuitable for the tire cord.

In the present invention, if the number of years of upper / lower smoke may be given differently, the upper edge is adjusted to 350TPM to 550TPM, and the lower edge is adjusted to 300TPM to 550TPM to produce a live cord with different numbers of upper and lower edges, respectively. The reason why the upper and lower stations are differently produced is that the lower the number of stations within the optimum properties of the raw cord, the lower the cost of the yarn and the more the economic benefits. A "twist constant" has been proposed as a constant for evaluating such kinks.

Raw cord is manufactured by using a weaving machine, and the obtained fabric is immersed in a dipping solution, and then cured to produce a tire cord having a resin layer attached to the surface of the raw cord. Make a 'Dip Cord'.

In more detail, the dipping process of the present invention, dipping is achieved by impregnating the surface of the fiber with a resin layer called RFL (Resorcinol-Formaline-Latex), which is inferior to the original rubber, To improve the disadvantages. In general, rayon fiber or nylon is subjected to one bath dipping, and in the case of using PET fiber, since the reactor on the surface of PET fiber is less than that of rayon fiber or nylon fiber, the surface of the PET is activated first and then the adhesive treatment is performed. (2 bath dipping). The lyocell multifilament according to the present invention uses one bath dipping. The dipping bath uses a known dipping bath for the tire cord.

The deep cord manufactured according to the above-described method has a total denier of 3000 to 6000 days, a twisting constant of 0.67 to 0.85, a cutting load of 14.0 to 35.0 kg, and can be advantageously used as a tire cord for a passenger car. .

In the present invention by using the prepared deep cord manufactures a tire for a passenger car. Specifically, a cord as shown in FIG. 2 is produced. More specifically, the carcass cord 13 using the lyocell has a total denier of 3,000 d to 6,000 d. The carcass ply 12 includes at least one layer of carcass ply reinforcement tire cords 13. The carcass ply 12 having the radially outer fly turnup 14 preferably comprises a carcass cord of one layer to two layers. The reinforcing carcass cord 13 is oriented at an angle of 85 ° -90 ° with respect to the circumferential intermediate surface of the tire 11. In the particular embodiment shown, the reinforcing carcass cord 13 is arranged at 90 ° with respect to the circumferential intermediate plane. For fly turnup 14, it is preferred to have a height of 40-80% relative to the tire maximum cross-sectional height. If the fly turn-up is less than 40%, the stiffness complementary effect of the tire sidewall is too low, and if it is 80% or more, the tire sidewall stiffness is too high, which adversely affects the riding comfort.

Figure 2 schematically shows the structure of a tire for a passenger car manufactured using the lyocell multifilament according to the present invention.

Hereinafter, FIG. 2 will be described in more detail as follows.

The bead regions 15 of the tire 11 each have an annular bead core 16 that is inextensible. The bead core is preferably made of a single or single filament steel wire wound continuously. In a preferred embodiment, high strength steel wires of 0.95 mm-1.00 mm diameter form a 4x4 structure, and it is also possible to form a 4x5 structure.

In a particular embodiment of the invention, the bead region also has a bead filler 17, in the case of the bead filler, it is necessary to have a hardness of at least a certain level, preferably Shore A hardness of 40 or more is preferred.

In the present invention, the tire 11 is reinforced with the crown portion by the belt 18 and the cap ply 19 structure. The belt structure 18 comprises two cutting belt plies 20 and the cords 21 of the belt plies are oriented at an angle of about 20 degrees with respect to the circumferential central surface of the tire. The cord ply 21 of the belt ply is arranged opposite to the direction of the cord 22 of the other belt ply in a direction opposite the circumferential central plane. However, the belt 18 may comprise any number of plies and may preferably be arranged in the range of 16-24 °. The belt 18 serves to provide lateral rigidity to minimize the rise of the tread 23 from the road surface during operation of the tire 11. The cords 21 and 22 of the belt 18 are made of steel cords and have a 2 + 2 structure, but can be produced in any structure. The cap ply 21 and the edge ply 24 are reinforced on the upper portion of the belt 18. The cap ply cord 25 in the cap ply 19 is reinforced in parallel to the circumferential direction of the tire, resulting in high speed rotation of the tire. It serves to suppress the change in the size of the circumferential direction, and a cap fly cord 25 having a large heat shrinkage stress at a high temperature is used. One layer of cap ply 19 and one layer of edge ply 21 may be used, but preferably, 1-2 layers of cap ply and also 1-2 layers of edge ply are reinforced.

In the present invention, as an example of the adhesive solution for the adhesion of the lyocell cord and the rubber can be prepared and used using the following method. The examples described below are only intended to more clearly understand the present invention and are not intended to limit the present invention.

29.4 wt% Resorcinol 45.6

Pure 255.5

37% formalin 20

10wt% sodium hydroxide 3.8

After preparing the solution, the reaction was stirred at 25 ° C for 5 hours, and then the following components were added.

40wt% VP-Latex 300

Pure 129

28% ammonia water 23.8

After the ingredient is added, the mixture is aged at 25 degrees for 20 hours to maintain a solid concentration of 19.05%.

After the drying, the adhesive liquid is applied. In order to adjust the amount of adhesion of the adhesive liquid, it is preferable to add a stretch of 0-3%, and more preferably, a stretch of 1-2% is required. If the stretch is too high, the adhesion amount of the adhesive solution can be controlled, but the result is a decrease in the elongation, resulting in a decrease in fatigue resistance, and if the stretch is too low, for example, less than 0%, the lyocell Dip fluid penetrates into the cord, making it impossible to control the DPU.

The adhesive amount is preferably 4% -6% by weight of the fiber based on the solid content. After passing through the adhesive liquid is dried at 120-150 ℃. Dry for 180 to 220 seconds. When drying the cord, it is important to dry the cord with 1% -2% stretch. In the case of lack of stretch, the cord's middle body and extension increase, which leads to insufficient physical properties for the tire cord. When the stretch is over 3%, the body's level is appropriate but the body's length is too low. Will occur.

After drying, heat treatment is performed in a temperature range of 130 to 170 ° C. The stretch during the heat treatment is maintained between -2-0%, the heat treatment time is appropriate 50 seconds-90 seconds. If the heat treatment is less than 50 seconds, the reaction time of the adhesive liquid is insufficient, resulting in low adhesive strength. If the heat treatment is longer than 90 seconds, the hardness of the adhesive liquid is increased, resulting in a decrease in fatigue resistance of the cord. Will be imported.

The present invention mainly describes the case of dipping using a two-bath dipping machine, but those skilled in the art will be able to perform heat treatment under the same conditions using a one-bath dipping machine.

Hereinafter, the structure and effect of the present invention will be described in more detail with specific examples and comparative examples, but these examples are only intended to more clearly understand the present invention, and are not intended to limit the scope of the present invention. In Examples and Comparative Examples, properties of the tire cord and the like were evaluated in the following manner.

(a) Tire cord strength (kgf) and middle elongation (%)

After drying at 107 ° C. for 2 hours, Instron's low-strength tensile tester was used. After twisting at 80 Tpm (80 twist / m), the sample was measured at 250 mm and a tensile speed of 300 m / min. The elongation at specific load imposed here represents the elongation at the point of 4.5 kg load.

(b) Dry heat shrinkage (%, Shrinkage)

After drying for 24 hours at 25 ° C and 65% RH, dry heat shrinkage was determined using the ratio of the length (L ₀ ) measured at 20g static load and the length (L ₁ ) after treatment at 20g static load for 30 minutes at 150 ° C. Indicates.

S (%) = (L ₀ -L ₁ ) / L ₀ × 100

(c) E-S

Elongation under constant load is referred to as intermediate elongation (E) in the present invention, where the load means 4.5 kg. The reason for evaluating elongation at 4.5kg is because it considers the maximum load per tire cord. And 'S' means the dry heat shrinkage of the above (b), the sum of the median elongation (E) and dry heat shrinkage (S) is referred to in the present invention as 'E-S'. In general, once the tire is vulcanized, the shrinkage and intermediate elongation of the cord change. The sum of shrinkage and median elongation is similar to the concept of modulus in the cord after the tire is fully manufactured. In other words, if the value of 'E-S' is low, the modulus increases. If the modulus is high, the force generation amount due to the deformation of the tire is easy, so it is easier to maneuver. On the contrary, it is possible to produce the same tension even with a small deformation. Can be. Therefore, the value of 'E-S' is used as a physical property value to determine the superiority of the code performance in tire manufacturing. In addition, when the tire is manufactured, the tire having a low E-S value has an effect of improving the uniformity of the tire since the amount of deformation due to heat is small, thereby improving the uniformity of the entire tire. Therefore, in the case of a tire using a cord having a low E-S value, since tire uniformity is more effective than a tire using a high cord, it is possible to improve tire performance.

E-S = Elongation at 4.5kg + Shrinkage

(d) Twisting constant (R)

The twist constant (R) is obtained by the following equation. Cords with the same twist constant mean that the joined single yarn is reinforced at the same angle relative to the length of the cord:

(Wherein R is the twist constant, N is the twist number D per 10 cm, and den is the total denier).

(e) Even with fatigue

The fatigue strength of the tire cord was measured by using the Goodrich Disc Factigue Tester which is commonly used for fatigue testing of tire cords. Fatigue test conditions were 120 ℃, 2500RPM, compression 10% and 18% conditions, and after the fatigue test was swelled in a tetra cholore ethylene solution for 24 hours to swell the rubber and the rubber and the cord was separated to measure the residual strength. The residual strength was measured after drying at 107 degrees for 2 hours using a conventional tensile strength tester according to the method (a) above.

(f) adhesion

Adhesion was measured by the H-test method based on ASTM D4776-98 method.

Example 1

Cellulose with a concentration of 11.5% using NMMO · 1H ₂ 0, propy1 gallate 0.01wt% together with pulp with a degree of polymerization (DPw) of 1,200 (α-cellulose content; 97%) and a powder of PVA 20: 1 by weight. After preparing the solution, the final filament fineness was adjusted to 1,650 denier and spun.

 The filament yarns were prepared by direct weaving machine and twisted into two joints as shown in Table 1 with the same number of upper and lower edges, respectively, and then immersed in a conventional RFL solution and heat treated to prepare 'Dip Cord' to evaluate physical properties.

TABLE 1

Example 1 sample A-1 A-2 A-3 A-4 A-5 A-6 A-7 Dip Cord    Soft water (TPM) up / down 360/360 400/400 420/420 450/450 470/470 500/500 520/520    Construction (Ply) 2 2 2 2 2 2 2    Twisting Constant (R) 0.63 0.71 0.75 0.86 0.87 0.92 0.93    Strong (kgf) 22.5 21.1 19.5 18.1 16.8 15.8 15.1    Intermediate Elongation (%) 1.7 1.8 2.0 2.2 2.2 2.3 2.5    Dry heat shrinkage (%) 0.2 0.2 0.3 0.3 0.4 0.4 0.4    E-S 1.9 2.0 2.3 2.5 2.6 2.7 2.9    Adhesion 11.0 12.8 12.9 13.3 14.5 14.5 14.8    Fatigue resistance (%) 85 85 86 87 87 88 90

Upper and lower stations are the same number of years. The raw cord was produced by two combinations. As the number of dips increased, the strength decreased and the median elongation and endothelial tendency increased.

Example 2

The filament yarns prepared as in Example 1 were twisted in two or three joints with different soft water using a direct twisting machine, and then immersed in a conventional RFL solution and heat-treated to prepare 'Dip Cord'. Evaluated.

TABLE 2

Example 2 sample B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8 Dip Cord    Soft water (TPM) up / down 420/320 420/470 420/520 470/420 320/520 420/320 420/470 420/520    Construction (Ply) 2 2 2 2 2 3 3 3    Twisting Constant (R) 0.63 0.71 0.75 0.86 0.87 0.60 0.67 0.71    Strong (kgf) 22.5 21.1 19.5 18.1 20.8 30.1 28.4 27.7    Intermediate Elongation (%) 1.7 1.8 2.0 2.2 2.2 1.8 2.1 2.3    Dry heat shrinkage (%) 0.2 0.2 0.3 0.3 0.4 0.1 0.3 0.3    E-S 1.9 2.0 2.3 2.5 2.6 1.9 2.4 2.6    Adhesion 11.0 12.8 12.9 13.3 14.5 13.3 14.5 15.1    Fatigue resistance (%) 85 88 92 87 91 87 88 90

In the case of two consecutive joints with different stations, the strength decreased and the fatigue resistance increased as the lower edge increased. However, even if the staging increased (420/520, 320/520) under the same lower combustion conditions, there was little change in fatigue resistance. In the case of three-ply joints, the strength was decreased and the middle elongation and fatigue were increased as the lower margin increased.

Example 3

From the same cellulose solution as in Example 1, the total denier of the filament was spun to 1000 denier and 2200 denier, and then twisted in two bonds using a direct yarn. The prepared raw cord was immersed in a conventional RFL solution and heat-treated to prepare a 'Dip Cord' to evaluate physical properties.

TABLE 3

Example 3 Sample condition C-1 C-2 C-3 C-4 C-5 C-6    Filament denier 1000 1000 1000 2200 2200 2200    Construction (Ply) 2 2 2 2 2 2    Soft water (TPM) up / down 350/350 400/400 470/470 300/300 350/350 420/420    Twisting Constant (R) 0.34 0.39 0.45 0.50 0.57 0.67    Strong (kgf) 18.5 15.7 13.7 27.1 26.4 23.8    Intermediate Elongation (%) 2.7 3.2 3.4 2.1 2.8 2.9    Dry heat shrinkage (%) 0.2 0.2 0.3 0.3 0.3 0.4    E-S 2.9 3.4 3.7 2.4 3.1 3.3    Fatigue resistance (%) 78 83 85 79 85 88

In case of two-ply yarns using lyocell filaments with denier of 1000 and 2200, the strength decreased significantly as the number of years increased, but the median elongation and fatigue fatigue tended to increase. On the other hand, dry heat shrinkage did not change significantly.

Comparative Example 1

By using the lyocell filament manufactured as in Example 1, the soft water was adjusted to 250/250, 300/300, and 520/520 in the same manner as in Table 4, and then immersed in a conventional RFL solution. 'Dip Cord' was prepared by heat treatment to evaluate physical properties.

TABLE 4

Comparative Example 1 Sample condition D-1 D-2 D-3    Filament denier 1650 1650 1650    Construction (Ply) 2 2 2    Training (TPM) 250/250 300/300 520/520    Twisting Constant (R) 0.42 0.51 0.96    Strong (kgf) 23.5 22.7 13.7    Intermediate Elongation (%) 0.7 0.1 3.4    Dry heat shrinkage (%) 0.2 0.2 0.3    E-S 2.9 3.4 3.7    Fatigue resistance (%) 50 53 94

When the service life is 250/250, 300 / 300TPM, the strength is very high (23.5kg, 22.7kg), but the fatigue resistance is remarkably low, indicating unsuitable physical properties as a tire cord. If the service life is 520/520, the fatigue resistance is high as 94%, but the strength is low, which is insufficient for proper strength as a tire cord.

According to the present invention, a tire of 235 / 45R17 95W was manufactured, and the weight of the tire was 11.9 Kg. In the present invention, when the tire is manufactured, the expansion process after vulcanization is omitted, and the RFV (Radial Force Variation) and LFV (Lateral Force Varition) are improved by 55 to 100% compared to the conventional polyester cord tires using the post-vulcanization expansion process. The results showed that the uniformity was improved. In addition, the present invention can prevent unnecessary waste of tire production and bring about energy saving.

Using tire cords with lyocell multifilaments with excellent physical properties (e.g., lower elongation and shrinkage, improved strength and modulus) as a tire cord is a tire for passenger cars with improved steering stability, shape stability and uniformity. To provide. In addition, the fatigue performance was confirmed to be improved compared to a tire using a conventional rayon tire cord. In particular, the present invention was confirmed that the growth of the outer radius is reduced by more than 10% compared to the case of the tire using a conventional rayon tire cord has excellent shape stability.

1 is a schematic representation of a spinning process according to the invention.

Figure 2 is a schematic diagram showing the structure of a tire for a passenger car manufactured using the lyocell multifilament according to the present invention.

Claims (5)

i) dissolving cellulose and PVA mixed powder in N-methylmorpholine N-oxide (hereinafter NMMO) / water mixed solvent to prepare a spinning stock solution (Dope); ii) an orifice having a diameter of 100 to 300 µm and a length of 200 to 2,400 µm, the spinneret including an orifice having a ratio of diameter to length (L / D) of 2 to 8 times and an interval between 2.0 and 5.0 mm between orifices; Extruding the spinning stock solution through the fibrous spinning stock solution to allow the fibrous spinning stock solution to pass through the air layer to reach a conical upper coagulation bath, and then solidify it to obtain a multifilament; iii) introducing the obtained multifilament back into the lower coagulation bath, changing the direction of travel thereof, and introducing it into a water washing bath to wash it; And iv) drying and emulsifying the multi-filament washed with water, v) manufactured by the method comprising the step of twisting the wound yarn with a twisting machine to produce a raw cord, weaving it immersed in a dipping liquid, a deep cord for a tire cord having the following physical properties. (1) Cutting load 14.0 to 35.0 kg, (2) Fineness 3,000 to 6,000 denier, (3) Resistance to fatigue more than 80%, (4) Adhesion to rubber 8.0 to 15.0 kg, (5) Twisting constant 0.30 to 0.95 ( 6) Sum of elongation at specific load and dry heat shrinkage at a tensile load of 4.5 kg (ES) 1.0 to 4.0 The method of claim 1, In the step iii), the PVA in the cellulose / PVA mixed powder is a polyvinyl alcohol having a polymerization degree of 1,000 to 4,000, and the content of the polyvinyl alcohol in the mixed powder is 0.5 to 30% by weight. The method of claim 1, The deep cord for the tire cord, characterized in that the soft water in the twisting step of step v) is 300/300 TPM to 500/500 TPM at the same time. The method of claim 1, The soft cord in the twisting step of step v) is characterized in that the upper cord is adjusted to 350TPM to 550TPM, and the lower lead is 300TPM to 550TPM, the number of years of the upper / lower lead is different. A tire comprising the deep cord for a tire cord according to any one of claims 1 to 4.