KR20040057550A - Method for preparing Lyocell multi-filament for tire cord and the Lyocell multi-filament prepared by the Method - Google Patents

Abstract

PURPOSE: Lyocell multi-filament is capable of producing tire cord having excellent physical properties. The tire cord has low elongation, increased strength, increased modulus, excellent drive stability, shape stability and uniformity. A manufacturing method thereof is characterized by increasing productivity. The lyocell multi-filament is useful for a tire for a passenger car. CONSTITUTION: Lyocell multi-filament is obtained by the steps of: (i) dissolving mixed powder of cellulose and PVA in a solvent mixed N-methyl morpholine N-oxide(NMMO) and water to prepare dope; (ii) spinning the dope through a spinning nozzle containing many orifices; passing fiber of the dope through air; coagulating the fiber into an upper part of a conic coagulating bath to manufacture multi-filament; (iii) change a course of the filament in a lower part of the coagulating bath; washing the filament in a washing bath; and then (iv) drying, oiling and winding the filament. The orifices has 100-300μm of diameter, 200-2400μm of length, 2-8times of the ratio of the diameter to the length, and 2.0-5.0mm of intervals between the orifices.

Description

Method for preparing lyocell multi-filament for tire cords, and lyocell multi-filament produced by the same {Method for preparing Lyocell multi-filament for tire cord and the Lyocell multi-filament prepared by the Method}

The present invention relates to a method for manufacturing a lyocell multifilament for a tire cord, and a lyocell multifilament produced by the same, a tire cord and a tire for a passenger car using the same, and more specifically, a spinning method using a two-stage solidification method, ) 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, 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 its progression, and introducing it into a washing bath to wash it; And iii) relates to a method for producing a lyocell multi-filament for tire cords comprising the step of winding and washing the multi-filament is washed with water.

Tire cords, which are used as the skeleton that forms the inside of tires, are currently using tire cords of various materials, including polyester cords, nylon cords, aramid cords, rayon cords, and steel cords. In terms of performance, (1) the strength and initial modulus are large (2) heat resistant and not brittle in dry and wet heat (3) fatigue resistance (4) form stability (5) excellent adhesion to rubber, etc. (Cf. 福 原 (纖維 和 工業, 1980 Vol. 36, pp 290). However, all known tire cords do not satisfy all of the various functions required above, so the uniqueness of each cord material can be avoided. Therefore, the use is determined and used.

For example, in the case of a high speed radial tire for a passenger car, which requires initial modulus, heat resistance, and shape stability among the above-mentioned performances, a tire made of rayon fiber having a low shrinkage rate and excellent shape stability due to the intrinsic properties of the fiber itself The 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. In particular, tire lateral stiffness increases. 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. In addition, not only the strength is excellent, but also strong and modulus characteristics that can be maintained during the moisture absorption that can occur in the production process is required.

On the other hand, lyocell fiber, 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, the modulus lower than the rayon (60%) has the advantage of low morphological change, can be considered as an alternative to the above needs, but as described later, the radiation for the TIO cord is problematic There is no tire cord yet.

Textiles used in tire cords or industrial materials have different physical properties such as strength and modulus. In line with this trend, fiber makers continue to improve fiber quality by utilizing a variety of fiber manufacturing techniques to maximize the performance of each material. 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 performed 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 during the solidification process based on the coagulation solution concentration and temperature.

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

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-295,672 discloses the improvement of the physical properties by the method of drawing and solidifying through the air layer during the manufacture of aramid fibers, US Patent 4,501,886 is used to radiate cellulose triacetate using the 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 the tertiary amine oxide-based aqueous solution to spin cellulose solutions. The use of an air layer to prevent sticking is disclosed, and US Pat. No. 4,261,943 discloses spraying non-solvent water to prevent sticking between filaments in an air layer in the range of 50 to 300 mm. The above technique can increase the orientation of the fiber spun by utilizing the air layer, but when directly applied to the production of lyocell multifilament for tire cords, there are process anxiety factors 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 an air layer by adding salts such as ammonium chloride or calcium chloride to a solution in which DP 5,000 cellulose was dissolved in NMMO. Although fiber of 56.7 cN / tex and 4% elongation after spinning was prepared, 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 the tire cord filament is made of several hundred strands of filament to be around 1,500 denier, 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 from 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 conditions for applying cooling air, and the coagulating fluid. A new design is needed to consider the drying conditions according to the direction of travel and the spinning speed.

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 has the disadvantage of being difficult to use as a tire cord yarn in terms of strength and productivity.

Therefore, there is a need in the art to solve the above problems and to develop a method for producing a lyocell yarn that can be used as a tire cord.

The present inventors have made a thorough study to prepare a lyocell yarn of the type that can be used as a tire cord to solve the above problems, using a two-stage solidification method, and mixed the cellulose and PVA powder as a spinning stock solution N-methylmorpholine N -Dissolve in oxide (NMMO) / water mixed solvent to prepare a spinning stock solution (Dope) by spinning the spinning stock solution through an orifice of a specific structure, the fibrous spinning stock solution through the air layer conical top coagulation bath After reaching, the solidified to obtain a multifilament, the obtained multifilament is introduced into the lower coagulation bath again, the direction of travel thereof is introduced into the water washing bath, washed with water, and the water washing completes the multifilament and In the case of winding by emulsion treatment, it is confirmed that the lyocell multifilament for tire cords having excellent physical properties can be manufactured. It came to invention.

After all, the present invention is to provide a method for producing a tire cord lyocell yarn with excellent strength and modulus, which can provide a tire for passenger cars with improved steering stability, shape stability, and uniformity with high productivity.

1 is a diagram schematically showing a process for producing a spinning stock solution in the manufacturing method according to the present invention.

2 is a schematic diagram schematically showing a spinning process according to the present invention.

Figure 3 is a schematic diagram schematically showing the structure of a tire for a passenger car manufactured using the lyocell multifilament according to the present invention.

One aspect of the present invention for achieving the above object is a spinning method using a two-stage solidification method, i) spinning cellulose and PVA mixed powder by dissolving in N-methyl morpholine N-oxide (hereinafter referred to as NMMO) / water mixed solvent Preparing a stock solution (Dope); Ii) an orifice having a diameter of 100 to 300 µm and a length of 200 to 2,400 µm, comprising a plurality of orifices having a ratio (L / D) of the diameter to length of 2 to 8 times and a spacing 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 lyocell multifilament; Iii) introducing the obtained multifilament back into the lower coagulation bath, changing its direction of introduction into the washing bath, and washing it; And iii) relates to a method for producing a lyocell multi-filament for tire cords comprising the step of winding and washing the multi-filament is washed with water.

Another aspect of the present invention relates to a lyocell multifilament having a total denier range of 1,000 to 2,500 and a cutting load of 9.0 to 15.0 kg, produced by the manufacturing method. The multifilament is composed of 500 to 1500 individual filaments having a fineness of 0.5 to 4.0 denier.

Another aspect of the present invention relates to a tire cord for a passenger car manufactured using the lyocell multifilament and a tire for a passenger car including the lyocell multifilament.

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. It is generally known that lignin has an amorphous structure and hemicellulose has a low crystalline structure. Therefore, in order to manufacture high quality cellulose fibers, it is preferable to minimize such components and use a high α-cellulose content. Excellent properties can be expected by high orientation structure and high crystallization using cellulose molecules having a high degree of polymerization. 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 production of spinning stock solution, NMMO uses NMMO monohydrate whose water content is adjusted to the 13wt% range.

In the method according to the present invention, to prepare 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 a high shear stress is required, 80 to Appropriate dissolution temperatures in the range of 130 ° C should be established. 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 produce a homogeneous spinning stock solution in which undissolved cellulose particles are not present, a process in which the cellulose / PVA mixed powder is uniformly mixed with the liquid NMMO before the dissolution process and the liquid NMMO penetrates and swells inside the cellulose powder is essential. Do. To this end, a method for producing a homogeneous cellulose solution 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, and tension. , The superposition is repeated, and then the swollen cellulose / PVA mixed powder is pasted and dissolved by continuous injection into an 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. If 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. Since NMMO is used to swell the cellulose / polyvinyl alcohol mixed powder in the kneader, the NMMO temperature during transport to the kneader is maintained at 80 to 90 ° C. The prepared cellulose / polyvinyl alcohol powder and the concentrated NMMO solution were injected into the kneader maintained at 75 to 80 ° C., and the mixed cellulose / polyvinyl alcohol powder content for NMMO was 5 to 20% by weight depending on the degree of polymerization of the cellulose polymer. 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, stretching, overlapping and shearing processes in the kneader, and the temperature is reduced to 75 to 75 during the transfer to the extruder. 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. Figure 2 schematically shows a spinning process according to the present invention, when the cellulose solution is quantitatively supplied from the gear pump 1 in the figure, the spinning stock solution discharged through the spinning nozzle 2 is passed through the air layer 3 in the vertical direction. A solid liquid interface is reached. The spinning nozzle used is usually circular in shape and has 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, so the cooling efficiency of the solution may be reduced and adhesion may occur before the discharged solution is solidified. If the nozzle diameter is too large, peripheral devices such as the spinning pack and the nozzle may become large, which is disadvantageous to the equipment surface. . 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 is slow, and NMMO water washing Is hard. If the length of the nozzle orifice is less than 200 μm, the orientation of the solution is not good, so the physical properties are bad. If the length of the nozzle orifice exceeds 2,400 μm, there is a disadvantage in that excessive cost and effort are required to manufacture the nozzle orifice.

Considering the tire cord and the industrial in terms of use, in consideration of the orifice interval 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 greater the number of filaments radiated, the greater the impact on radioactivity and the need for advanced spinning technology. In order to solve this problem, the present invention uses a spinneret including the number of orifices satisfying the above-described specific conditions within the above range. If the number of orifices is less than 500, the fineness of each filament becomes thick, so that NMMO cannot be sufficiently released within a short time, so that solidification and washing cannot be completed completely. In addition, if the number of orifices exceeds 1,500, it is easy to generate close filaments and close-ups in the air layer section, and the stability of each filament decreases after spinning, which leads to deterioration of physical properties and subsequent problems in the twisting and heat treatment process for application to tire cords. Can cause.

When the fibrous spinning stock solution passed through the spinning nozzle 2 is solidified 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, making it difficult to obtain a dense and uniform fiber. . Therefore, even when the cellulose solution is spun, the same discharge amount can be obtained into the coagulating liquid with a smaller diameter by maintaining the appropriate air layer 3. Too short air gap distances increase the rate of micropore generation during rapid surface layer solidification and desolvation, which impedes the increase of 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, and to determine the atmosphere of the air layer and the inlet of the cooling air supply device 6 Sensor 5 is attached between the filaments to monitor the 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, filament solidification is promoted, which is disadvantageous for high-speed spinning, and 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 may affect the solidification process of the filament, the relative humidity in the air layer should be adjusted to RH10% to RH50%. More specifically, RH 10% to 30% of dried air in the vicinity of the nozzle and RH 30% to 50% of humid air in the vicinity of the coagulating solution can increase stability in terms of filament solidification rate and fusion of the spinneret surface. have. The cooling air is blown horizontally on the side of the filament discharged vertically, and 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 it is difficult to produce a uniform filament by causing the difference of solidification rate and trimming of the filament where the cooling air reaches the latest on the spinning nozzle. If it is too high, the filament yarn shakes, which hinders the risk of adhesion and 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. Accordingly, a donut-shaped mesh network 7 is installed on the surface of the upper coagulation bath, and the coagulation bath is designed to flow down the coagulating solution in the same direction as the direction of the filament so that the stretching orientation may proceed naturally.

In step iii) of the method according to the invention, the obtained multifilament is introduced again into the lower coagulation bath, the direction of travel thereof is switched to introduce a water bath, and this is washed with water. More specifically, in FIG. 2, the lower coagulation bath 8 recovers the coagulating liquid 10 flowing down along with the filament in the upper coagulation bath, and the roller 9 is installed inside the coagulation bath to switch in the horizontal direction. Roller 9 rotates to reduce frictional resistance. The concentrations of the upper coagulation bath and the coagulation fluid are equal or less than 0.5%, and a control bath is installed separately to circulate so that the concentrations of the upper coagulation bath 4 and the lower coagulation bath 8 are the same or within 0.5%. Have a car. As the filament passes through the upper coagulation bath and the lower coagulation bath, the desolvent and the stretching are performed at the same time, which greatly affects the formation of physical properties. The filaments that have passed through the bottom coagulation bath are washed in the water 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.

It is a lyocell multifilament with a total denier range of 1,000 to 2,500 and a cutting load of 9.0 to 15.0 kg produced by the method according to the invention. The multifilament is composed of 500 to 1500 individual filaments having a fineness of 0.5 to 4.0 denier. At this time, the strength of the multi-filament is 6.0 to 9.5 g / d, elongation is 3.5 to 5.7%, elongation is 0.5 to 4.0% when the load is 4.5kg, modulus is 250 to 400 g / d, for passenger cars It can be advantageously used as a tire cord.

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.

The lyocell multifilament manufactured by the above method is twisted with two wound yarns by a direct weaving machine in which both twisting and joining are performed simultaneously to produce a 'raw cord' for a tire cord. The raw material cord is manufactured by adding Ply Twist to a tire cord yarn and then adding it to Cable Twist, and in general, the upper and lower ends are applied with the same degree. To give the upper and lower edges at the same value makes it easier for the manufactured tire cords to maintain a straight line without showing rotation or twisting. Physical properties change. In general, when the kink is high, the strength decreases, and the body and the body tend to increase. The fatigue fatigue tends to improve with the increase of twist. A "twist constant" has been proposed as a constant for evaluating such kinks. Manufactured 'raw code

(Raw Cord) is a 'deep cord' for tire cords that is woven using a high speed weaving machine, the obtained fabric is immersed in a dipping liquid, and then cured to attach a resin layer to the surface of the 'Raw Cord'. (Dip Cord) '. Dipping RFL to the surface of the fiber

It is achieved by impregnating a resin layer called (Resorcinol-Formaline-Latex), which is carried out to remedy the disadvantages of the fibers for tire cords, which are inherently poor in adhesion with rubber. 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, and a cutting load of 14.0 to 28.0 kg, which can be advantageously used as a tire cord for a passenger car. .

A tire for a passenger car is manufactured using the prepared deep cord. Specifically, a code as shown in FIG. 3 is produced. More specifically, the carcass code 13 using the lyocell has a total denier of 3,000 d to 6,000 d. The carcass ply 12 includes at least one carcass ply reinforcement tire cord 13. The carcass ply 12 with radially outer fly turnup 14 preferably comprises a carcass cord of one layer to two layers. The reinforcement 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 about 40-80% of the maximum tire cross-sectional height. If the fly turn-up is less than 40%, the stiffness complementary effect of the tire side wall is too low. If the fly turn-up is more than 80%, the tire side wall stiffness is too high, which adversely affects the riding comfort.

As shown in FIG. 2, 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 by the crown portion by the belt 18 and the cap fly structure 19. 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 21 of the belt ply is arranged opposite to the direction of the cord 22 of the other belt ply in a direction opposite to the circumferential center plane. However, 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 the 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 manufactured in any structure.

Cap ply 21 and edge ply 24 are reinforced on the upper part of the belt 18.

The cap fly code 25 in 19 reinforces in parallel to the circumferential direction of the tire to suppress the size change in the circumferential direction due to the high-speed rotation of the tire, and uses the cap fly code 25 having a large heat shrinkage stress at a high temperature. One layer of cap fly 19 and one layer of edge fly 24 may be used, but preferably, 1-2 layers of cap fly and also 1-2 layers of edge fly are reinforced.

EXAMPLE

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, characteristics of the spinning solution, lyocell multifilament, and the like were evaluated by the following method.

(a) Degree of Polymerization (DP _w ):

The intrinsic viscosity [IV] of the dissolved cellulose was measured in a concentration range of 0.1 to 0.6 g / dl at 25 ± 0.01 ° C. with 0.5M cupriethylenediamine hydroxide solution made according to ASTM D539-51T using a Uberod viscometer. . Intrinsic viscosity is obtained by extrapolating specific viscosity according to concentration and substituting it into the equation of Mark-Houwink to obtain polymerization degree.

[IV] = 0.98 × 10 ^-2 DP _w ^0.9

(b) filament adhesion

Cut five pieces of filament yarn into 1M units and cut only 0.1M of them, make five samples, dry them at 107 ℃ for 2 hours under no load, and check the adhesion of the filaments through the tube through the image analyzer. At this time, it is determined as "fail (F)" when even one strand is stuck, and "pass (P)" otherwise.

(c) strength (kgf) and elongation (%)

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

(d) 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

(e) 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 (d), 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 intermediate elongation is similar to the concept of modulus in the cord after the tire has been completely manufactured. In other words, if the value of 'E-S' is low, the modulus increases. If the modulus is high, it is easier to control due to the large force generation due to the deformation of the tire, and on the contrary, it is possible to use less deformation in order to create the same degree of tension. 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

(f) 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).

(g) even with fatigue

The fatigue strength was compared by measuring the residual strength after the fatigue test using the Goodrich Disc Fatigue Tester which is commonly used for the fatigue test of tire cords. Fatigue test conditions were 120 ℃, 2500RPM, elongation + 2.5% / compression 12% conditions, after immersion in a tetra chloro ethylene solution for 24 hours after the fatigue test to swell the rubber and to separate the rubber and cord 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 (c) above.

Example 1

A cellulose solution having a concentration of 11.5% was prepared using 0.01 wt% of NMMO.1H ₂ O and propyl gallate together with pulp and PVA mixed powder having a degree of polymerization (DP _W ) of 1,200 (α-cellulose content; 97%). Spinning nozzles having a diameter of 120 mm and an orifice number of 800, 1000, and 1200 were used, and an orifice diameter of 150 μm was used. At this time, the nozzle of all orifice diameter and length (L / D) of 4 was used. The solution discharged from the spinning nozzle (head temp; 110 ° C) gives cooling air with a temperature and humidity of 20 ° C / 40% RH at a wind speed of 4m / sec when the air gap distance passes 50mm. Spinning was performed by adjusting the discharge amount and spinning speed so that the filament fineness became 1,500 to 2,000 denier. The coagulation solution temperature was 20 ℃, the concentration was adjusted to 80% water, NMMO 20% circulating the coagulation liquid of the upper coagulation bath and lower coagulation bath. At this time, the concentration of cooling air and coagulant was continuously monitored using a sensor and a refractometer. The remaining NMMO of the filament leaving the coagulation bath was removed by washing with water and wound up after drying, and the filament yarn physical properties at this time are shown in Table 1.

There was no problem in the number of nozzle orifices in the radioactivity. In terms of physical properties, the strength increased slightly as the number of orifices increased, and the middle and cut elongations were lowered. On the modulus side, the orifice number was highest at 1200. When the filament denier was controlled from 1,500 to 2,000 by controlling the discharge amount and spinning speed, the adhesiveness during spinning was not significantly affected. In terms of physical properties, the strength decreased but the elongation increased as the filament denier increased.

Example 2

Using 0.01 wt% NMMO · 1H ₂ O, propyl gallate with a mixture of pulp and PVA with a degree of polymerization (DP _W ) of 800 (α-cellulose content; 97%) and 1,200 (α-cellulose content; 97%) A cellulose solution was prepared.

At this time, the concentration of pulp having a polymerization degree of 800 was 13.5%, and the pulp having a polymerization degree of 1,200 was adjusted to 11.5%. Spinning nozzles with a diameter of 120 mm and an orifice number of 1,000 were used, and three types of orifice diameters were used, including 120 μm, 150 μm, and 200 μm, respectively. At this time, the ratio (L / D) of the orifice diameter and the length was all 5 nozzles. Cooling air was applied to the air layer under the same conditions as in Example 1, and the discharge amount and the spinning speed were adjusted so that the final filament fineness was 1,500 denier. The filament yarn physical properties at this time are shown in Table 2. The filament yarn manufactured was twisted with 40 times / 10cm lower edge in Z direction, 40 times / 10cm upper edge in 2 direction or upper edge / low edge 34/34, 3 mixture in direct direction with a direct twisting machine, and then Dip cord was prepared by immersion and heat treatment, and the physical properties are shown in Table 2.

We used pulp with DP of 800 and 1,200 using nozzles with 1,000 orifices.

As the nozzle orifice diameter increased, the strength tended to increase generally, but the change was much larger when pulp with a DP of 800 was used. Elongation decreased, modulus tended to increase and the highest strength and modulus were achieved when pulp with DP of 1200 and nozzle orifice diameter of 200. Dip Cord was prepared after heat treatment and the physical property was confirmed that the strength of the 16--18.3kgf in the case of 2 go, 27.3kgf in the case of 3 go.

Example 3

In Example 2, a cellulose solution having a concentration of 11.5% was prepared using a pulp / PVA mixed powder having a polymerization degree (DP _W ) of 1,200, and then a nozzle having a diameter of 120 mm, an orifice number of 1,000, and an orifice diameter of 150 μm was used. Cooling air was imparted to the air layer under the same conditions as in Example 2, and discharged by adjusting the discharge amount and spinning speed so that the final filament fineness was 1,500 denier, and wound up after washing with water and drying after coagulation. The filament yarn was twisted using a direct weaving machine in the lower edge of 35 to 47 times / 10cm in the Z direction, the upper edge double or 35/47 times / 10cm in the S direction, or the upper edge / lower edge 37 to 42/37 to 42, 3 After immersing in a conventional RFL solution and heat-treated to prepare a 'Dip Cord', Table 3 shows the physical properties.

As the number of years increased from 35 times / 10cm to 47 times / 10cm under the condition of 2, the elongation increased but the strength decreased significantly, and the E-S value also decreased. However, due to the increase in elongation, fatigue resistance improved. In the case of 3 go, as strength increased from 37 times / 10cm to 42 times / 10cm, strength decreased, but elongation and fatigue fatigue increased.

Comparative Example 1

As in Example, a pulp having a degree of polymerization (DP _W ) of 1,200 (α-cellulose content; 97%) was used, and the physical properties of the filaments with respect to the number of orifices of the nozzle were examined when the orifice diameter of the nozzle was 150 µm. When the orifice number is 400, there is no problem of radioactivity, but the rate of solution discharge from the nozzle is very fast compared to the take-up speed.

(The ratio of winding speed / solution discharging speed) dropped, causing a problem of lowering the strength. Table 4 shows the spinning results using a nozzle with an orifice number of 1,000 and adjusting the denier of the entire filament to 800 and 2,300. If the Deyer is 800, the strength is very low, and greatly falls short of the strength required when the tire cord is applied later, and when the Deyer is 2,300, it becomes a big problem because the excess cord amount is required for the tire. As a result of experiments by changing the nozzle orifice diameter, when the nozzles with 90㎛ and 350㎛ were used, the radiation was not good and the single yarn occurred. Especially, when 350㎛, the adjacent filament and the adhesive generated a lot, so the physical properties of the filament after spinning Markedly reduced.

According to the present invention, a tire of 235 / 45R17 95W was manufactured, and the weight of the tire was 11.9 Kg. After tire manufacturing, RFV and LFV measurements resulted in a 25% improvement over conventional rayon cord tires, resulting in improved uniformity.

When using the method according to the invention, it is possible to obtain lyocell multifilaments with excellent physical properties (for example, lower elongation, improved strength and modulus) as tire cords. Used to provide a tire for a passenger car with improved steering stability, shape stability and uniformity.

Claims (10)

A spinning method using a two-stage solidification method, i) dissolving cellulose and PVA mixed powder in an 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, with 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 its progression, and introducing it into a washing bath to wash it; And iii) drying and emulsifying the multi-filament having been washed with water, and winding the lyocell multifilament for a tire cord. The method of claim 1, wherein 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. Manufacturing method. The method of claim 1, wherein in the step (ii), the air layer is present at intervals of 20 to 300mm, supplying cooling air to the air layer and the temperature thereof is 5 ℃ to 20 ℃, the relative humidity RH in the air layer is Maintaining between 10% and 50%. The method of claim 1, wherein in (ii), the orifice is 500 to 1500 in the spinning nozzle. A lyocell multifilament made by the method according to claim 1 with a total denier range of 1,000 to 2,500 and a cutting load of 9.0 to 15.0 kg. The multifilament has a strength of 6.0 to 9.5 g / d, an elongation of 3.5 to 5.7%, an elongation of 0.5 to 4.0% when the load is 4.5 kg, and a modulus of 250 to 400 g / d. Lyocell multifilament, characterized in that. A raw cord for a tire cord is manufactured by twisting two or three lyocell multifilaments of claim 5 or 6 with a direct weaving machine, weaving them in a high-speed loom, and then dipping them into a dipping liquid. Dip cord for tire cord obtained by curing after dipping. The dip cord according to claim 7, wherein the dip cord has a total denier of 3000 to 6000 days, a twisting constant of 0.67 to 0.85, and a cutting load of 14.0 to 28.0 kg. A tire for a passenger car comprising the lyocell multifilament of claim 5 or 6. A tire comprising the deep cord of claim 7.