KR100524795B1 - Lyocell tire cord having good adhesion - Google Patents

Abstract

The present invention relates to a tire cord having excellent adhesion to rubber using high-strength lyocell filaments. More specifically, A) cellulose and PVA (polyvinyl alcohol) mixed powder is N-methylmorpholine N-oxide (hereinafter, NMMO) / water in the mixed solvent to prepare a spinning stock solution (Dope); B) extruding the spinning stock solution through a spinning nozzle including 500 to 1,500 orifices, and then solidifying it to obtain a multifilament; C) introducing the obtained multifilament into a washing bath to wash it, and drying and emulsifying the washed multifilament, and d) twisting the wound yarn with a twister to prepare a raw cord, and then weaving it into a dip It relates to a tire cord manufactured by the method comprising the step of immersing in ping liquid.

   The lyocell tire cord manufactured using the lyocell filament manufactured as described above has an elongation at specific load and dry heat shrinkage when the cutting load is 14.0 to 35.0 kg, a total denier 3000 to 6000 denier, and a tensile load of 4.5 kg. The sum (ES) of the shrinkage (ES) is 1.0 to 4.0, in particular, the adhesive strength with the rubber is more than 10.0kg, it is characterized by using it to provide a passenger car tire excellent in shape stability and steering stability.

Description

Lyocell tire cord having good adhesion

The present invention relates to a tire cord using a lyocell filament having excellent adhesive strength containing polyvinyl alcohol.

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. (Ref .: 福 原 (纖維 和 工業, 1980 Vol. 36, pp 290). However, all known tire cords do not satisfy all of the above-mentioned various functions. 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 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. 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, 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 having a relatively low deterioration and less change in shape 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 have different physical properties such as strength, modulus and adhesion to rubber, unlike textiles where color expression and handling are important.

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 addition, 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 the improvement of physical properties by stretching and solidifying through an air layer when preparing aramid fibers, and US Pat. No. 4,501,886 describes cellulose triacetate using an air layer. It starts spinning. U.S. Patent No. 4,261,943 also discloses spraying non-solvent water to prevent adhesion of filaments to air layers 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 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 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 No. 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. Filament is only 50 strands. Considering the fact that a tire cord filament is usually made of several hundred strands of filament around 1,500 denier, it is difficult to secure the required physical properties of the tire cord after the twisting and dipping. In fact, in spinning of fibers, it is more difficult to control the cooling, drying, and washing conditions of fibers during spinning of the denier fibers than the spinning of the denier fibers, which results in a certain level of physical properties and overall uniformity of the filaments. Since it is difficult to do it, it is difficult to apply it to an industrial company simply by 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.

U.S. Patent No. 5,252,284 used the filament number from 800 to 1,900, but as a result of spinning under the condition of short air layer within 10mm and the winding speed of 45m / min., The elongation was 15.4% due to the low stretching orientation. As 47.8 cN / tex, it is difficult to be used 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 and extracting a mixture of cellulose and polyvinyl alcohol 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 adhesion and the strength of the fiber are 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 there is still a need for a high strength lyocell fiber which is more adhesive than the conventional rayon fiber.

Conventionally, various methods for improving the adhesiveness of a tire cord to rubber are known.

In general, a representative method for imparting adhesiveness with rubber to a tire cord is a reaction product of a halogenated phenol and resorcinol, and a reaction product of a halogenated phenol and formaldehyde as RFL (initial condensation of resorcinol and formaldehyde). It is a method of using what was mixed with the liquid which consists of water, rubber latex, etc. (reference patent: 46-11251). An example of the halogenated phenol is 2,6-bis (2 ', 4'dihydroxyphenylmethyl) -4-chlorophenyl (commonly abbreviated as' package').

However, in the case of giving the tire cord adhesiveness with the rubber in this manner, a sufficient amount of adhesive adhered to the tire cord can be obtained. In addition, halogenated phenols, such as capsules, must use alkaline ammonia water to increase the adhesion between tire cords and rubber. At this time, a large amount of alkali used remains in the fiber, and the remaining alkali hydrolyzes the tire cord. In particular, when the rubber reinforcement tire cords manufactured by the above method are thermally aged, hydrolysis of the tire cords by alkali is promoted by heat, so that the adhesive strength between the tire cord and the rubber is significantly lowered under high temperature. .

Another conventional method is a method in which a tire cord is primarily treated with a mixed solution of an epoxy compound and a diisocyanate, and secondly, with a liquid composed of RFL (reference: US Patent No. 3,234,067). The diisocyanate used is blocked with caprolactam or phenol. In this way, if the tire cord is attached with rubber, the adhesive treatment process (hereinafter referred to as the "dipping process") is performed in two stages, which is cumbersome, and the obtained deep cord is hard. There are disadvantages such as poor.

In response to these demands, the present inventors have completed the present invention by finding that they are suitable for use in industrial or tire cords by adding polyvinyl alcohol to the cellulose / NMMO solution to produce cellulose fibers with excellent adhesion to rubber. It came to the following.

The present inventors solved the above problem and produced a lyocell yarn of a type that can be used as a tire cord having excellent adhesion 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. When the fibrous spinning solution passes through the air layer to obtain a multifilament, the obtained multifilament is introduced into a water washing bath, washed with water, and the multifilament having been washed with water is dried and tanned and wound up as a reinforcing material in the tire. It was confirmed that the lyocell multifilament that maintains excellent adhesion even in a high temperature environment for a long time in the used state, and led to the present invention.

It is a technical object of the present invention to provide a tire cord and a tire for a passenger car having improved steering stability, shape stability, and uniformity using the lyocell multifilament manufactured as described above.

The present invention for achieving the above object is A) preparing a spinning solution (Dope) by dissolving the cellulose and PVA mixed powder in N-methyl morpholine N-oxide (hereinafter, NMMO) / water mixed solvent; B) extruding the spinning stock solution through a spinning nozzle including 500 to 1,500 orifices, and then solidifying it to obtain a multifilament; C) introducing the obtained multifilament into a washing bath to wash it, and drying and emulsifying the washed multifilament, and d) twisting the wound yarn with a twister to prepare a raw cord, and then weaving it into a dip It relates to a tire cord comprising the step of immersing in ping liquid.

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

In the tire cord of the present invention, in step A), 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, it is known that lignin has an amorphous structure and hemielluose 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. 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 60 to 130 ° C. should be formed. When the dissolution temperature is higher than 130 ° C, there are disadvantages in that the molecular chain end groups increase due to the molecular weight decrease by thermal decomposition of cellulose, which lowers mechanical properties and disadvantages that cause decomposition of NMMO. There are disadvantages of increasing the time and energy required for the preparation and preparing 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.

Method for preparing a high homogeneous cellulose solution for this purpose is to supply the powdered cellulose mixed with polyvinyl alcohol continuously to the extruder maintained at 65 to 105 ℃ with concentrated liquid NMMO, homogeneous by mixing, swelling and dissolving in the extruder Prepared with one cellulose solution.

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 extruder together with cellulose / PVA powder. Here, the cellulose / polyvinyl alcohol mixed powder content for NMMO is such that the final concentration is 5 to 20% by weight, more preferably 9 to 16% by weight, depending on the degree of polymerization of the cellulose polymer.

In step B) of the method according to the invention, an orifice having a diameter of 100 to 300 μm and a length of 200 to 2.400 μm, wherein the ratio of diameter to length (L / D) is 2 to 8 times, and the spacing between 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 1 schematically shows a spinning process according to the present invention, when the cellulose solution is quantitatively supplied from the gear pump 1 in Figure 1, the radiation source solution extracted through the spinning nozzle (2) in the vertical direction of the air layer ( 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 the radioactivity. If the diameter of the nozzle orifice exceeds 300 µm, the solidification rate of the solution in the coagulation bath after spinning is slow, and NMMO water washing Becomes hard. If the length of the nozzle orifice is less than 200 μm, the orientation of the solution is poor, and the physical properties are bad. If the length of the nozzle orifice is more than 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, considering 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. On the other hand, if the number of orifices is more than 1,500, adjacent filaments and affixes are likely to occur in the air layer section, and the stability of each filament decreases after spinning, resulting in 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 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 filament adhesion, atmospheric 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, filament solidification is promoted, which is disadvantageous for high-speed spinning, and if the temperature is higher than 20 ° C, the permeation 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 it is difficult to produce a uniform filament by causing a difference in solidification rate and trimming of the filament where the cooling air reaches the latest on the spinning nozzle. If too high, the filament yarn shakes, which hinders the risk of sticking and the 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%.

In step C) 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 switched to introduce a 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 greatly affects 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 step C) of the method according to the present 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 lyocell 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 D) 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. The raw cord is manufactured by adding Ply Twist to the lyocell yarn for tire cords and then adding them together with Cable Twist, and 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, elongation, mesothelioma, fatigue resistance, etc. change depending on the level of twisting (years) 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 the upper and lower edges were given the same value. It is for maximizing physical property expression, making it easy to maintain a straight line without showing. 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 strong degradation is large and is not suitable for the tire cord.

In the present invention, if the number of years of upper / lower smoke may be given differently, in this case, the upper lead is adjusted to 350TPM to 550TPM, and the lower lead is adjusted to 300TPM to 550TPM to produce a live cord with different stations. 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.

Raw cord is manufactured 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 a surface of the fiber with a resin layer called RFL (Resorcinol-Formaline-Latex), which is a disadvantage of the fibers for tire cords that are inherently poor in adhesion to rubber. Is carried out to improve.

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 scope of 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 ° C. for 20 hours to maintain a solid concentration of 19.05%.

After the drying, the adhesive liquid is imparted. In order to adjust the adhesion amount 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 2% to 8% by weight of the fiber based on the solid content. After passing through the adhesive liquid, it is dried at 100 to 200 ℃. Drying is performed for 100 seconds to 300 seconds, and when the cord is dried, it is important to dry the cord with a stretch of about 1 to 3%. In the case of lack of stretch, the cord's middle body and extension increase, which leads to insufficient physical properties to apply to the tire cord. When the stretch is over 3%, the middle body level is appropriate but the body's length is too low. Will occur.

After drying, heat treatment is performed in a temperature range of 100 to 200 ° C. Stretch during heat treatment is maintained between -2 to 0%, the heat treatment time is appropriate 50 seconds to 300 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 300 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.

The deep cord manufactured according to the above-described method has an adhesive force of 10 kg or more, preferably 10 to 30 kg, total denier of 2000 to 6000 dare, and a cutting load of 14.0 to 35.0 kg. It can be used advantageously.

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 2,000 d to 6,000 d. The carcass ply 12 comprises at least one layer of carcass ply reinforcement tire cords 13. The carcass ply 12 with 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 present 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 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 to the circumferential center 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.

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 in 20g stop 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'.

E-S = Elongation at 4.5kg + Shrinkage

(d) 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 immersion in a tetra chloro ethylene solution for 24 hours to swell the rubber and then separated 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.

(f) adhesion

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

Example 1

Pulp with a degree of polymerization (DPw) of 1,200 (α-cellulose content; 97%) and a powder obtained by mixing 20: 1 polyvinyl alcohol having a weight average degree of polymerization of 1700 and a saponification degree of 99.5% by weight with NMMO.1H ₂ Inject the extruder into a cellulose solution with a concentration of 11.5% by using 0 to swell the cellulose powder sufficiently with a residence time of 7 minutes in the cellulose swelling zone, and then maintain each block temperature at 80 to 95 ° C in the melting zone of the extruder The screw was operated at 200 rpm to completely dissolve, and then spun through a nozzle to adjust the final filament fineness to 1,650 deniers.

The solution discharged during spinning was a homogeneous state containing no undissolved cellulose particles, and the degree of cellulose polymerization in the discharged solution was 980.

 The filament yarns were twisted with 39/39 soft water each by using a direct weaving machine, and then immersed in a conventional RFL solution and heat-treated to prepare a deep cord, thereby evaluating physical properties.

Example 2

In the same Example 1, a pulp having a degree of polymerization (DPw) of 1,200 (α-cellulose content; 97%) and a polyvinyl alcohol having a weight average degree of polymerization of 1700 and a saponification degree of 99.5% were mixed at a weight of 10: 1 by weight. In the same manner as the cellulose solution was prepared and discharged through a nozzle. The concentration of the discharged solution was 11.5% by weight, homogeneous in the absence of undissolved cellulose particles, and the degree of cellulose polymerization in the discharged solution was 950.

The filament yarns were twisted with 39/39 soft water each by using a direct weaving machine, and then immersed in a conventional RFL solution and heat-treated to prepare a deep cord, thereby evaluating physical properties.

Example 3

Polyvinyl alcohol having a degree of polymerization of 2500 and a degree of saponification of 99% of polyvinyl alcohol was dissolved in liquid NMMO, a cellulose solution was prepared in the same manner as in Example 1, and discharged through a nozzle. The concentration of the discharged solution was 11.5% by weight, homogeneous in the absence of undissolved cellulose particles, and the degree of cellulose polymerization in the discharged solution was 950.

The filament yarns were twisted with 39/39 soft water each by using a direct weaving machine, and then immersed in a conventional RFL solution and heat-treated to prepare a deep cord, thereby evaluating physical properties.

Comparative Example 1

After cellulose with a weight average degree of polymerization of 1000 was injected into a twinscrew extruder with a liquid NMMO (monohydrate) of 89 ° C, which was ground to 500 µm or less in diameter, each block temperature was kept at 95 ° C and dissolved. It was discharged and spun.

The concentration of the solution was 11.5% by weight. When the solution was observed under a polarizing microscope, an undissolved powder having a diameter of 50 to 100 μm was present, and the degree of cellulose polymerization was 740.

The filament yarns were twisted with 39/39 soft water each by using a direct weaving machine, and then immersed in a conventional RFL solution and heat-treated to prepare a deep cord, thereby evaluating physical properties.

TABLE 1

Deep Code Properties Example 1 Example 2 Example 3 Comparative Example 1 Strong (kg) 21.1 23.4 22.6 18.1 Dry heat shrinkage (%) 0.2 0.3 0.2 0.4 E-S 2.3 2.4 2.3 3.0  Adhesion to rubber (kg) 15.6 18.5 17.4 11.7 Fatigue resistance (%) 83 84 86 73 Beauty Analysis ¹⁾ 0 0 0 23 Fibril Index One One One 6

1) Number of undissolved distribution in the area of 5 × 5 ㎜

Example 4

The radial tire manufactured using the lyocell dip cord manufactured by Example 2 of the present invention has a carcass layer having a radially outer fly turn up, and the carcass layer is a lyocell dip prepared by Example 4. The code was installed to include the first floor. At this time, the specifications of the carcass cord were as shown in Table 2 below, and were oriented at a 90 degree angle with respect to the circumferential intermediate surface of the tire. The fly turn up 4 has a height of 40 to 80% with respect to the maximum tire cross-sectional height. The bead part 5 had a bead core 6 having a high strength steel wire having a diameter of 0.95 to 1.00 mm 4 × 4 and a bead filler 7 having a shore A hardness of 40 or more. The belt 8 is reinforced by a belt reinforcement layer with a top layer of cap ply 9 and a first layer of edge ply 14 so that the cap fly cord in the cap ply 9 is parallel to the circumferential direction of the tire. Placed.

Comparative Example 2

A tire was manufactured in the same manner as in Example 4, except that the lyocell deep cord manufactured according to Comparative Example 1 of the present invention was used as a cord material for manufacturing a tire. At this time, the specifications of the carcass cord were as shown in Table 2 below, and were oriented at a 90 degree angle with respect to the circumferential intermediate surface of the tire.

Comparative Example 3

A tire was manufactured in the same manner as in Example 4 except for using a conventional viscose rayon as a cord material for manufacturing a tire. At this time, the specifications of the carcass cord were as shown in Table 2 below, and were oriented at a 90 degree angle with respect to the circumferential intermediate surface of the tire.

[Table 2]

Example 4 Comparative Example 2 Comparative Example 3 Carcass Material Lyocell (Example 2) Lyocell (Comparative Example 1) Rayon Specification (d / ply twisted yarn) 1650d / 2 1650d / 2 1650d / 2 Strong (Kg) 23.4 18.1 17.0 Modulus of elasticity (g / d) 120 105 60 Cap fly Material nylon nylon nylon Specification (d / ply twisted yarn) 1260d / 2 1260d / 2 1260d / 2 Strong (Kg) 24 24 24 Modulus of elasticity (g / d) 30 30 30 tire Flat ratio 0.60 0.60 0.60 Carcass floors One One One Cap fly floor 2 2 2

The 215/60 R15 V tire manufactured according to Example 4 and Comparative Examples 2 and 3 was mounted on a 2000cc class passenger car, and the noise generated in the vehicle was measured while driving at a speed of 60 km / h, thereby preventing noise in the audible frequency range. (dB), and the steering stability and ride comfort were evaluated by an experienced driver by driving a test course in units of 5 out of 100 points, and the results are shown in Table 3 below. Durability is based on FMVSS 109's P-metric tire endurance test method, measuring 38 degrees Celsius (± 3 degrees) and 85, 90, 100% of the tire's nominal load. A total of 34 hours was used to determine the pass (OK) when no trace of bead separation, cord cutting, belt separation, etc. was found in any part of the tread, sidewall, carcass cord, inner liner, or bead. .

Table 3

division Example 4 Comparative Example 2 Comparative Example 3 Tire weight (kg) 9.95 10.04 10.12 Ride 100 90 95 Steering stability 100 95 95 durability OK OK OK Uniformity 100 95 97 Noise (dB) 61.4 64.5 63.2

According to the test results of Table 3, the tire according to the present invention (Example 4) is compared to the case of applying the lyocell manufactured by Comparative Example 1 and the conventional rayon cord to carcass (Comparative Examples 2 and 3). It can be seen that the weight of the tire is reduced, so that the rolling resistance can be reduced. In addition, the performance of the present invention using the lyocell deep cord manufactured by the present invention in the carcass in terms of performance was excellent in terms of riding comfort, steering stability and noise reduction, and the tire uniformity is also improved. have.

The lyocell tire cord manufactured using the lyocell filament manufactured as described above is particularly excellent in adhesive strength with rubber of 10.0 kg or more, cutting load of 14.0 to 35.0 kg, total denier 2000 to 6000 denier, and tensile load of 4.5 kg. The sum (e) of elongation at specific load and dry heat shrinkage ratio (ES) is 1.0 to 4.0, by which it is characterized by providing a passenger car tire having excellent shape stability and steering stability.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims. .

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 (4)

A) dissolving cellulose and PVA mixed powder in N-methylmorpholine N-oxide (hereinafter NMMO) / water mixed solvent to prepare a spinning stock solution (Dope), B) extruding the spinning stock solution through a spinning nozzle including 500 to 1,500 orifices, and then solidifying it to obtain a multifilament, C) introducing the obtained multifilament into a water washing bath to wash it, and drying and emulsifying the multifilament having been washed with water, winding up; D) manufactured by a method comprising the step of twisting the wound yarn with a twisting machine to produce a raw cord, weaving it soaked in a dipping liquid, a deep cord for a cord having excellent adhesive properties having the following physical properties. (1) 12.0 kg or more of adhesion to rubber, (2) 14.0 to 35.0 kg of cutting load, (3) 2,000 to 6,000 deniers of fineness, (4) 80% or more of fatigue resistance, and (5) elongation at 4.5 kg of tensile load ( Sum of elongation at specific load and dry heat shrinkage (ES) 1.0 to 4.0 The method of claim 1, In step A), 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, A deep cord for a cord, characterized in that the adhesive force with the rubber is 13 to 25 kg. A tire comprising the carcass layer with a deep cord for a cord according to any one of claims 1 to 3.