KR101551426B1 - High performance radial tire - Google Patents

Abstract

The present invention relates to a radial pneumatic tire having a flatness ratio of 0.70 or less, comprising a pair of parallel bead cords, at least one radial carcass ply wound around the bead cores, a belt layer laminated on the outer periphery of the carcass ply, And a circumferential belt reinforcing layer formed on the outer peripheral side of the belt layer, wherein the carcass ply includes a dipped cord made of polyether terephthalate fibers, the polyether terephthalate fibers having the following properties And at the same time an elongation of less than 2.5% when subjected to an initial stress of 2.0 g / d, an initial modulus value of 80 to 120 g / d, elongation of less than 7.5% when subjected to 6.0 g / And a force-deformation curve extending from the tensile strength of 9.5 g / d until the yarn is cut.

(1) an intrinsic viscosity of 0.90 to 1.05, (2) a strength of 9.5 g / d or more, (3) an elongation of 12% or more, (4) a birefringence of 0.20 or more, (5) a density of 1.381 to 1.398, Shrinkage of 8%

Radial tires, Carcass, Ultra high strength, Polyethylene terephthalate, Fiber

Description

[0002] High performance radial tires [0003]

TECHNICAL FIELD [0001] The present invention relates to a high performance radial tire in which a polyethelene terephthalate cord having excellent shape stability at a high temperature and high strength is applied to a carcass ply, and more particularly to a radial pneumatic tire having a flatness of 0.70 or less, At least one radial carcass ply wound around the bead core, a belt layer laminated on the outer periphery side of the carcass ply, and a circumferential belt reinforcing layer formed on the outer circumferential side of the belt layer, The carcass ply comprises a dipped cord made of polyether terephthalate fibers, said polyether terephthalate fibers having less than 2.5% elongation when subjected to an initial stress of 2.0 g / d and having an initial Modulus value, elongation of less than 7.5% when subjected to a mid-term stress of 6.0 g / d, and tensile strength of 9.5 g / d Extending, force-directed to a radial pneumatic tire, characterized in that it has a variation curve.

Conventional radial tires consisted of a carcass ply reinforced with rubber with a fiber cord such as regular polyester, rayon or aramid, and a belt structure reinforced with steel cord.

The bead wire is reinforced at the contact portion between the tire and the rim to prevent the tire from coming off the rim and to maintain stability, and this bead wire also serves to fix the carcass ply.

In the first pneumatic tires, cotton canvas paper was used as carcass material, and fiber cords such as rayon, nylon, and regular polyester were used as carcass ply material according to the development of man-made fibers. Recently, Code and so on.

Regular polyesters are generally used as air-fed radial tires, and more specifically, as carcass ply materials for air inlet radial tires having a flatness ratio of 0.65 to 0.82, and in addition, they have a low flatness ratio, more specifically, a flatness ratio of less than 0.70 Rayon is used as a carcass ply reinforcement of high-speed air inlet radial tires.

In recent years, some of regular polyesters have been used in radial tires having a low flatness ratio at high speed, but their application is limited due to their low temperature properties and shape stability compared to rayon.

In addition, since general rayon has disadvantages in terms of production method, physical properties, and tire production process, it has been restricted in application to general radial tires. In general, conventional rayon has been produced using indirect substitution method and has many problems due to complicated manufacturing process and environmental effects. Therefore, it has many problems in view of recent trends that emphasize environmental impacts.

In addition, from the viewpoint of physical properties, the wet strength is too low, which is not suitable for a tire cord, and when applied to a tire, there is a disadvantage that the strength of the tread is lowered due to cracks or water penetration due to scratches, thereby decreasing the durability of the tire.

In addition, there is a problem that the water content should be controlled to 2% or less in tire production.

Due to the above-described problems, conventional tires using rayon as carcass have been limited in their use despite their excellent shape stability and high temperature properties.

It is an object of the present invention to provide a high performance radial tire in which a polyethelene terephthalate cord excellent in high temperature shape stability and deep cord strength is applied to a carcass ply.

According to a preferred embodiment of the present invention, there is provided a radial pneumatic tire having a flatness of 0.70 or less, comprising: a pair of parallel bead cords; and at least one radial crown wound around the bead cores, And a circumferential belt reinforcing layer formed on an outer peripheral side of the belt layer, wherein the carcass ply includes a deep cord made of polyether terephthalate fiber Wherein said polyether terephthalate fibers have the following physical properties and at the same time elongate less than 2.5% when subjected to an initial stress of 2.0 g / d, having an initial modulus value of 80 to 120 g / d, A tensile strength of less than 7.5% when subjected to mid-range stress, and a force-strain curve extending from the tensile strength of 9.5 g / d until the yarn is cut. A pneumatic tire is provided.

(1) an intrinsic viscosity of 0.90 to 1.05, (2) a strength of 9.5 g / d or more, (3) an elongation of 12% or more, (4) a birefringence of 0.20 or more, (5) a density of 1.385 to 1.395, Shrinkage of 8%

According to another preferred embodiment of the present invention, there is provided a radial pneumatic tire characterized in that the carcass ply is used as one or two layers.

According to another preferred embodiment of the present invention, the radial pneumatic tire is characterized in that the dipped cord reinforcement density in the carcass ply is 20 to 40 EPI.

According to another preferred embodiment of the present invention, the dip cord has a twist number of 300 to 500 TPM.

According to another preferred embodiment of the present invention, the dip cord has a radial pneumatic tire of E ^2.25 (elongation at ^2.25 g / d) + FS (free shrinkage) of 6.5% or less.

The present invention can prepare an ultrahigh strength poly (ethylene terephthalate) fiber by improving the stretchability in the stretching step by controlling the force-strain curve and microstructure of the unstretched filament by applying a solvent emulsion excellent in stretchability and thermal efficiency, The processing cord formed from warp yarns is excellent in dimensional stability and strength and can be usefully used as a reinforcing material for rubber products such as tire and belt or for other industrial applications. Further, by applying the ultrahigh-strength polyethylene terephthalate cord of the present invention to a carcass ply of a high-performance radial tire, satisfactory results can be obtained with respect to durability, ride comfort, steering stability, and the like of the tire. Further, by applying ultra-high strength poly (ethylene terephthalate) fibers, a lighter weight tire can be provided.

The present invention can be applied to a tire cord 13 for reinforcing a carcass ply in a carcass ply 12 of a tire 11 as shown in Fig. 4 by applying a polyethelene terephthalate dip cord having a high- will be.

In the present invention, as a pre-stage for producing a polyethelene terephthalate dip cord to be applied to a carcass ply, a high-strength poly (ethylene terephthalate) fiber is produced using the following process.

(A) extruding a discharged yarn containing 85 mol% or more of ethylene terephthalate units and having an intrinsic viscosity in the range of 0.90 to 1.05 at a temperature of 280 to 305 ° C, and (B) passing the molten discharged yarn (C) a step of applying a solvent emulsion having excellent extensibility and thermal efficiency while reducing the coefficient of friction between filaments, (D) a step of stretching a polyester filament part (hereinafter referred to as "POY yarn" ) Is less than 6% when subjected to an initial stress of 0.5 g / d and has an initial modulus of 20 to 100 g / d with a force-strain curve of at least 150% elongation when subjected to 3.5 g / d And winding the yarn at a spinning speed such that the birefringence is 0.02 to 0.05; and (D) a step of multi-step stretching the wound yarn at a total mullion ratio of 3.0 or less, thereby producing a polyethylene terephthalate multifilament yarn .

The present invention also meets the following properties and at the same time elongates less than 2.5% when subjected to an initial stress of 2.0 g / d, has an initial modulus value of 80 to 120 g / d and is subjected to a mid-stress of 6.0 g / d To a tensile strength of 9.5 g / d, until the yarn is cut. ≪ Desc / Clms Page number 7 > The present invention relates to a polyethylene terephthalate stretching yarn having a force-

(1) an intrinsic viscosity of 0.90 to 1.05, (2) a strength of 9.5 g / d or more, (3) an elongation of 12% or more, (4) a birefringence of 0.20 or more, (5) a density of 1.381 to 1.398, Shrinkage of 8%

The polyethylene terephthalate polymer used in the present invention contains at least 85 mol% of ethylene terephthalate units, and preferably consists only of ethylene terephthalate units.

Alternatively, the polyethylene terephthalate may incorporate a small amount of units derived from one or more ester-forming components other than ethylene glycol and terephthalene dicarboxylic acid or derivatives thereof as a copolymer unit. Examples of other ester forming components that can be copolymerized with the polyethylene terephthalate unit include glycol such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and the like, and polyhydric alcohols such as terephthalic acid, isophthalic acid, hexahydroterephthalic acid, Dicarboxylic acids such as dicarboxylic acid, bibenzoic acid, adipic acid, sebacic acid and azelaic acid.

Preferably, the polyethylene terephthalate chip according to the present invention is produced by melt-mixing terephthalic acid (TPA) and an ethylene glycol raw material at a ratio of 1.1 to 2.0, and transesterifying and polycondensation of the molten mixture to obtain an intrinsic viscosity of 0.60 to 0.70 Solid phase polymerized to have an intrinsic viscosity of 1.00 to 1.20 and a water content of 20 ppm or less at 235 to 245 캜 and under vacuum at a temperature of 235 to 245 캜.

If the intrinsic viscosity of the chip is lower than 1.00, the intrinsic viscosity of the final stretch yarn is lowered and the ultrahigh strength can not be exhibited as a treated cord after heat treatment. If the intrinsic viscosity of the chip is higher than 1.20, excessive heat generation and screw load So that melt spinning becomes impossible. When the moisture content of the chips exceeds 20 ppm, hydrolysis is induced during melt spinning.

In the present invention, as an optional polymerization catalyst, an antimony compound, preferably antimony trioxide, can be added in an amount such that the residual amount of the antimony metal in the final polymer is 180 to 300 ppm, When the amount is less than 300 ppm, more than necessary amount of antimony metal acts as a foreign substance, thereby deteriorating spinning and drawing workability.

The thus prepared polyethylene terephthalate chip is fiberized according to the method of the present invention, and Fig. 1 schematically shows a manufacturing process according to one embodiment of the present invention.

In step (A), the polyethylene terephthalate chip is passed through the pack 1 and the nozzle 2, preferably at a spinning temperature of 280 to 305 占 폚, preferably 500 to 1000, The linear velocity at the linear velocity / the linear velocity at the nozzle), it is possible to prevent the viscosity of the polymer from being lowered by pyrolysis and hydrolysis. If the radiation draft ratio is less than 500, the uniformity of the filament cross section becomes worse and the drawing workability deteriorates remarkably. If it exceeds 1000, filament breakage occurs during spinning, and normal yarn is difficult to produce.

In the step (B), the molten discharge yarn 4 of the step (A) is quenched and solidified by passing through the cooling zone 3, and if necessary, the distance from the bottom of the nozzle 2 to the starting point of the cooling zone 3 That is, a length (L) of the hood.

This zone is referred to as a delay cooling zone or a heating zone, which has a length of 30 to 120 mm and a temperature of 320 to 400 ° C (air contact surface temperature).

In the cooling zone 3, an open quenching method, a circular closed quenching method, and a radial outflow quenching method can be applied according to a method of blowing cooling air, . Then, the emulsion applying device 5, in which the solidified discharged yarn 4 passes through the cooling zone 3 while reducing the frictional coefficient between the filaments and applying the solvent emulsion excellent in stretchability and thermal efficiency, You can ring.

In step (C), POY elongates less than 5% when subjected to an initial stress of 0.5 g / d, has an initial modulus of 20 to 100 g / d, has a minimum elongation of 150% when subjected to 3.5 g / d The yarn is wound at a spinning speed having a force-deformation curve and a birefringence of 0.02 to 0.05, and a preferable spinning speed is 1800 to 2,800 m / min.

In the present invention, the force-strain curve and the birefringence of POY yarn are used as factors for controlling the microstructure of the POY yarn.

Particularly, in the present invention, POY is elongated to less than 5% when subjected to an initial stress of 0.5 g / d, has an initial modulus of 20 to 100 g / d, is elongated at least 150% And a force-strain curve.

It is possible to maximize the stretchability in the stretching process in which the POY yarn having the force deformation curve continuously proceeds thereafter.

In the present invention, the birefringence of the POY yarn is used as a factor controlling the microstructure of the unstretched phase together with the force-strain curve.

In particular, in the present invention, as described above, excellent extensibility in the stretching process can be obtained even when the POY yarn force variation curve and the birefringence satisfy the ranges described above. This is because if the birefringence of POY is less than 0.02, the crystallization rate becomes too slow in the stretching step and can not sufficiently induce the formation of a tie chain between crystals. If the birefringence exceeds 0.05, crystallization proceeds too rapidly during stretching, It is difficult to manufacture ultrahigh-strength yarn because the stretchability deteriorates.

In the step (D), the yarn passed through the first stretching roller 6 is passed through a series of stretching rollers 7, 8, 9 and 10 by a spin draw method, Is stretched 2.0 to 3.0 times to obtain the final drawn yarn 11.

In the present invention, the POY yarn is stretched in three stages and each stretching temperature is made to be 95 ° C or lower than the glass transition temperature of POY yarn. If the stretching temperature is lower than the glass transition temperature, ° C., the crystallization during drawing proceeds rapidly, and the three-stage stretching is difficult.

The drawn polyethylene terephthalate fibers prepared according to the process of the present invention meet the following physical properties and at the same time elongate less than 2.5% when subjected to an initial stress of 2.0 g / d and have an initial modulus value of 80 to 120 g / d , Elongation of less than 7.5% when subjected to a mid-term stress of 6.0 g / d, and elongation until the yarn is cut from a tensile strength of at least 9.5 g / d.

(1) an intrinsic viscosity of 0.90 to 1.05, (2) a strength of 9.5 g / d or more, (3) an elongation of 12% or more, (4) a birefringence of 0.20 or more, (5) a density of 1.381 to 1.398, Shrinkage of 8%

In the present invention, ultrahigh-strength poly (ethylene terephthalate) fibers satisfying the above physical properties are prepared by twisting with a twisted yarn to produce a raw cord, then weaving the same into a dipping solution to provide a polyether terephthalate dip cord.

Hereinafter, the twisting, weaving and dipping processes of the present invention will be described in more detail.

The polyether terephthalate stretched yarn produced by the above method is obtained by twisting two wound yarns with a direct twisted yarn in which twisted yarn and twin yarn are simultaneously wound to form a yarn for a tire cord Cord) '. The raw cord is manufactured by applying a ply twist to a polyether terephthalate yarn for a tire cord and then applying and twisting the cable twist. Generally, the upper and lower rims are subjected to the same training or different training as required .

An important result of the present invention is that the physical properties such as the strength of the cord, the tensile strength and the fatigue resistance of the cord are changed according to the degree of twisting (number of years) given to the poly (ethylene terephthalate). Generally, when the twist is high, the strength is decreased, and the mid- and long-spirals tend to increase. My fatigue shows a tendency to improve with increasing kinks. The softening temperature of the polyether terephthalate tire cord prepared in the present invention was 300/300 TPM to 500/500 TPM at the same time as the upper and lower tires. It is easy to maintain a straight line image without showing twist and the like, thereby maximizing the manifestation of physical properties. At this time, when the temperature is less than 300/300 TPM, the loss of the cord is decreased and the fatigue is easily deteriorated. If the TPM is higher than 500/500 TPM, the strength is deteriorated.

In the present invention, the upper and lower hearths may be alternately arranged at different temperatures. The upper and lower hearths may be adjusted to 350 TPM to 450 TPM, and the lower and upper halves may be adjusted to 300 TPM to 450 TPM, respectively. The reason why the training is different is that the lower the annual training within the optimal physical property range of the raw code, the less the cost of the training and the economic profit. A "twist constant" is proposed as a constant for evaluating this twist.

The produced 'Raw Cord' is woven using a weaving machine, and the resultant fabric is dipped in the dipping solution and then cured to form a tire cord with a resin layer on the 'Raw Cord' surface 'Dip Cord' is manufactured.

The dipping process of the present invention will be described in more detail. The dipping process is achieved by impregnating the surface of the fiber with a resin layer called RFL (Resorcinol-Formaline-Latex) . In the case of using PET fiber, since the reactors on the surface of the PET fiber are smaller than those of the rayon fiber or the nylon fiber, the PET surface is first activated before the adhesion treatment is performed (2 bath dipping). The ultrahigh strength poly (ethylene terephthalate) yarn according to the present invention uses two-bath dipping. Dip bathing uses a known dip bath for tire cords.

The present invention relates to a material for a carcass ply of an air inlet radial tire, which comprises a high-tenacity polyethelene terephthalate fiber produced by the above-described method, a high-temperature physical property, The present invention provides a high performance air inlet radial tire having improved shape stability and fatigue performance and a flatness ratio of 0.70 or less.

Particularly, according to the present invention, the polyether terephthalate fiber used in the carcass ply should have an elongation of less than 2.5% at a stress of 2.0 g / d or less. If the elongation is more than 2.5%, a severe deformation of the carcass ply The handling stability is remarkably reduced. Also, in the present invention, it is necessary to have a force-strain curve that elongates less than 7.5% when subjected to a stress of 6.0 g / d. If elongation exceeds 7.5%, deformation of the carcass easily occurs, Falls.

Specifically, a tire as shown in Fig. 4 is manufactured. More specifically, the carcass ply reinforcing cord 13 using the ultrahigh-strength polyethelene terephthalate dip cord manufactured according to the present invention has a total denier of 2,000 d to 8,000 d. The carcass ply 12 includes at least one layer of carcass ply reinforcing tire cord 13. It is preferable that the dipped cord reinforcing density of the carcass ply 12 is 20 to 40 EPI. If the reinforcing density is less than 20 EPI, the mechanical properties of the carcass ply drop sharply. If the reinforcing density is more than 40 EPI, to be.

The carcass ply 12 having radially outer flyturn 14 preferably comprises carcass cords of one to two layers. The carcass ply reinforcement cord 13 is oriented at an angle of 85 ° to 90 ° with respect to the circumferential intermediate surface of the tire 11. In the particular embodiment shown, the carcass ply reinforcement cord 13 is arranged at 90 degrees with respect to the circumferential intermediate plane. In the case of the fly turn-up 14, it is preferable to have a height of about 40 to 80% with respect to the maximum cross-sectional height of the tire. If the fly turn-up is less than 40%, the stiffening effect of the tire side wall is too low. If the fly side turn-up is less than 40%, the tire side wall stiffness is too high.

4 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 non-stretchable. The bead core is preferably made of a single or single filament wire wound continuously. In a preferred embodiment, a high strength steel wire having a diameter of 0.95 mm to 1.00 mm forms a 4x4 structure, and it is also possible to form a 4x5 structure.

In a specific embodiment of the present invention, the bead region also has a bead filler 17, which, in the case of the bead filler, needs to have a hardness above a certain level, preferably a Shore A hardness of at least 40 Is preferred.

In the present invention, the crown portion is reinforced by the belt 18 and the cap ply 19 structure. The belt structure 18 includes two cut belt ply 20 and the cord 21 of the belt ply is oriented at an angle of about 20 degrees with respect to the circumferential center plane of the tire. The cord 21 of the belt ply is disposed opposite to the direction of the cord 22 of the other belt ply, in the direction opposite the circumferential center plane. However, the belt structure 18 may comprise any number of plys, and may preferably be arranged in the range of 16 ° to 24 °. The belt structure 18 serves to provide lateral stiffness to minimize the rise of the tread 23 from the road surface during operation of the tire 11. [ The belt cords 21, 22 of the belt structure 18 are made of steel cords and have a 2 + 2 structure, but can be made of any structure. The cap ply 19 and the edge ply 24 are reinforced on the upper portion of the belt 18 so that the cap ply cords 25 in the cap ply 19 are reinforced parallel to the circumferential direction of the tire, The cap fly cords 25 having a function of suppressing the size change in the circumferential direction and having a large heat shrinking stress at a high temperature are used. One layer of cap ply 19 and one layer of edge ply 24 may be used, but preferably one or two layers of cap ply and also one or two layers of edge ply are reinforced.

Hereinafter, the constitution and effects of the present invention will be described in more detail with reference to specific examples and comparative examples. However, these examples are merely intended to clarify the present invention and are not intended to limit the scope of the present invention. Properties of the tire cord and the like in Examples and Comparative Examples were evaluated by the following methods.

(1) Intrinsic viscosity (I.V.)

Phenol and 1,1,2,3-tetrachloroethanol in a weight ratio of 6: 4 were dissolved in a reagent (90 ° C) for 90 minutes so that the concentration of the sample became 0.4 g / 100 ml, and then Ubbelohde ) Was transferred to a viscometer and maintained at 30 ° C in a thermostatic chamber for 10 minutes, and the falling seconds of the solution were obtained by using a viscometer and an aspirator. The number of drops of the solvent was also determined by the same method, and the RV value and the IV value were calculated by the following equations (1) and (2).

(2) Tire cord strength (kgf) and elongation at break (%)

The sample was allowed to stand at 25 ° C and 65% RH for 24 hours and then subjected to a low speed elongation tensile tester manufactured by INSTRON Co., which was measured at a sample length of 250 mm and a tensile speed of 300 m / min after twisting 80 TPM (twist 80 m) do. The elongation at specific load represents the elongation at a point of load of 6.8 kg.

(3) Dry Heat Shrinkage (%, Shrinkage)

The ratio of the length (L ₀ ) measured in a stationary state of 20 g to the length (L ₁ ) after being treated with a static load of 20 g for 30 minutes at 150 ° C after leaving at 25 ° C and 65% RH for 24 hours was used to calculate the dry heat shrinkage .

S (%) = (L ₀ - L ₁ ) / L ₀ 100

(4) E-S

The elongation under a constant load is referred to as intermediate elongation (E) in the present invention, where the load means 6.8 kg. In particular, the reason for evaluating the elongation at a load of 6.8 kg is that the maximum load per tire cord is taken into consideration. S 'means the dry heat shrinkage rate in the above item (d), and the sum of the elongation modulus E and the dry heat shrinkage rate S is referred to as' E-S' in the present invention. Generally, as the tire vulcanizes, the shrinkage moderate elongation of the cord changes. The sum of shrinkage and modulus of elongation is similar to the modulus concept of the code after the tire is fully fabricated. That is, when the value of 'E-S' is low, the modulus becomes higher. If the modulus is high, it is easier to steer because of the large amount of force generated due to the deformation of the tire. On the other hand, it is possible to make a small deformation to produce the same tensile force. . Therefore, the value of 'E-S' is used as a property to judge the superiority of code performance in the tire manufacturing. In addition, since the amount of deformation caused by heat is small in a tire having a low E-S value in the manufacture of a tire, the uniformity of the tire is improved, thereby improving the uniformity of the tire as a whole. Therefore, in the case of a tire using a code having a low E-S value, it is possible to improve the tire performance because the uniformity of the tire is higher than that of a tire using a high code.

E-S = elongation at 6.8 kg + dry shrinkage

(5) Twist constant (R)

The torsional constant (R) is obtained by the following equation. Codes with the same twist constant mean that the combined single yarns are reinforced at the same angle with respect to the longitudinal direction of the cord:

(Where R is the tangent constant, N is the number of twists per 10 cm, D is the total denier, and rho is the specific gravity).

(6) My fatigue

The fatigue resistance of the tire cord was measured by measuring the residual strength after fatigue test using a Goodrich Disc Factigue Tester, which is commonly used in fatigue testing of tire cords. The fatigue test conditions were 120 ℃, 2500RPM, compression 12% and elongation 6%. After the fatigue test, the rubber was swelled by tetrachlorethylene solution for 24 hours, Were measured. The residual strength was measured according to the above (3) method using a normal tensile strength tester.

(7) Adhesion

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

(8) Birefringence

Is measured by the following method using a polarizing microscope equipped with a Berek compensator.

· Place the polarizer and the analyzer in the vertical position (→ orthogonal polarization)

• Insert a compensator into the analyzer at an angle of 45 ° (45 ° in the N-S direction of the microscope).

• Place the sample on the stage and place it in diagonal position (nγ-direction: 45 ° angle with the polarizer) (black compensation band appears at this position)

• Rotate the Compensator's micrometer screw to the right to read the scale at the point where the center of the sample is darkest.

· As you rotate it in the opposite direction again, read the scale at the darkest point.

· Divide the difference between the readings of the scale above by 2 and refer to the table made by the manufacturer to obtain the retardation (γ, nm).

• Remove the compensator and analyzer and measure the thickness (d, nm) of the sample using an eyefilar micrometer.

· Calculate the birefringence (Δn) of the sample by substituting the measured retardation and thickness into the following equation.

 ? N =? / D

[Example 1]

A solid phase polymerized polyethylene terephthalate chip having an intrinsic viscosity (I.V.) of 1.14 and a water content of 10 ppm containing 220 ppm of antimony metal was prepared. The produced chip was melt-spun using an extruder at a discharge temperature of 290 DEG C at a discharge rate of 900 g / min and a radiation draft ratio of 850. Then, the discharged yarn was solidified by passing through a heating zone (atmosphere temperature 340 ° C) of 60 mm directly below the nozzle and a cooling zone (blowing of cooling air having a wind velocity of 0.5 m / sec at 20 ° C) of 500 mm in length, Containing 70% paraffin oil component). The POY yarn was wound at a spinning speed of 2200 m / min. The first stage stretching was performed at 1.9 times at 60 DEG C, the second stage stretching at 1.2 DEG C at 60 DEG C, the third stretching at 1.3 DEG C at 75 DEG C, C and then 2.5% relaxed and then wound to produce a final drawn yarn (yarn) of 1500 denier.

The prepared cord yarn was wound up and down at 370 turns / m to prepare a cord yarn. The cord yarn was immersed in an adhesive liquid (PCP resin + RFL) in a dipping tank and then subjected to 1.5% , Dried for 150 seconds at 240 ° C in a hot stretching zone, and then heated and fixed for 150 seconds under 4.5% stretching. Subsequently, the film was immersed in RFL and then dried at 170 ° C for 100 seconds. The film was thermally fixed for 40 seconds at 240 ° C under -5.5% .

The properties of the thus-prepared drawn yarn and dipped cord were evaluated and are shown in Table 2 below.

[Examples 2 to 3 and Comparative Examples 1 to 3]

Experiments were conducted in the same manner as in Example 1 while varying the intrinsic viscosity, the spinning temperature, the length or the temperature of the heating zone, or the birefringence index of the POY yarn as shown in Table 1 to prepare a drawn yarn and a dip cord .

The properties of the thus-prepared drawn yarn and dipped cord were evaluated and are shown in Table 2 below.

 ■: Appearance defect, ■■: Appearance is extremely bad, meaning no manufacturing of treated cord.

[Example 4]

A radial tire manufactured using the ultra high tenacity polyethylene terephthalate dip cord manufactured by Example 1 of the present invention has a carcass ply having a radially outer side fly turnup, The prepared ultra high strength poly (ethylene terephthalate) dip cord was installed so as to include one to two layers. At this time, the specifications of the carcass cords were as shown in Table 4 below, and were oriented at an angle of 90 degrees 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 cross-sectional height of the tire. The bead portion 5 has a bead core 6 having a 4 x 4 high strength steel wire having a diameter of 0.95 to 1.00 mm and a bead filler 7 having a hardness of 40 or more and a shore A hardness of 40 or more. The belt 8 is reinforced by a belt reinforcing layer consisting of one layer of cap ply 9 and one layer of edge ply 14 at the top so that the cap ply cords in the cap ply 9 are parallel to the circumferential direction of the tire Respectively.

[Comparative Example 4]

A tire was produced in the same manner as in Example 4, except that the cord material for tire fabrication was made of the polyether terephthalate dip cord manufactured in Comparative Example 3. [

[Comparative Example 5]

A tire was produced in the same manner as in Example 4, except that rayon was used as a cord material for tire production.

The 225/60 R15 V tire manufactured according to Example 4 and Comparative Example 4-5 was mounted on a 2000cc class passenger car and was driven at a speed of 60 km / h to measure the noise generated in the vehicle, (dB). Steering stability and ride quality were evaluated by a skilled driver on a test course and evaluated in units of 5 points out of 100 points, and the results are shown in Table 5 below. The durability was measured in accordance with the P-metric tire endurance test of FMVSS 109 at a temperature of 38 degrees Celsius (3 degrees Celsius), 85, 90 and 100% h for a total of 34 hours and it was judged as OK (OK) when no traces of bead separation, cord cutting, belt separation, etc. were found in any part such as tread, sidewall, carcass cord, inner liner, bead .

division Example 4 Comparative Example 4 Comparative Example 5 Tire Weight (kg) 9.85 9.89 10.12 Ride comfort 100 94 95 Steering stability 100 95 95 durability OK OK OK Uniformity 100 93 97 Noise (dB) 60.3 63.2 63.2

From the results of the tests of Table 5, it can be seen that the tire according to the present invention (Example 4) reduces the weight of the tire compared to the case where rayon code is applied to carcass (Comparative Example 5) Can be reduced. Also, from the viewpoint of performance, the present invention using the ultrahigh-strength polyethelene terephthalate cord produced by the present invention as a carcass has excellent effects on riding comfort, steering stability and noise reduction, It can be seen that it is improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the appended claims. .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram schematically illustrating the spinning process of a poly (ethylene terephthalate) fiber according to the present invention.

Fig. 2 is an example of the force-strain curve of the polyether terephthalate POY yarn of the present invention.

Figure 3 is an example of the force-strain curves of the inventive poly (ethylene terephthalate) stretchers.

4 is a schematic view schematically showing the structure of a tire for a passenger car manufactured using a high-strength polyethelene terephthalate dip cord according to the present invention.

* A brief description of key symbols in the drawings

11: Tire 12: Carcass fly

13: Carcass ply reinforcement cord 14: Fly turn-up

15: bead region 16: bead core

17: bead filler 18: belt structure

19: cap fly 20: belt fly

21, 22: belt cord 23: tread

24: edge fly 25: cap fly cord

Claims (4)

A radial pneumatic tire having a flatness ratio of more than 0 and not more than 0.70, At least one radial carcass ply wound around the bead core, a belt layer laminated on the outer circumferential side of the carcass, and a circumferential belt reinforcing layer formed on the outer circumferential side of the belt layer , Said carcass ply comprising a dipped cord made of polyether terephthalate fibers, The polyethylene terephthalate fiber is oil-lubricated with a solvent emulsion and satisfies the following physical properties and 2.0 to 2.5% elongation when subjected to an initial stress of 2.0 g / d, having an initial modulus value of 80 to 120 g / d, Characterized in that it has a force-strain curve that elongates by at least 12% until a yarn is cut from a tensile strength of 9.5 g / d, with 6.5 to 7.5% elongation when subjected to 6.0 g / tire. (1) an intrinsic viscosity of 0.90 to 1.05, (2) a strength of 9.5 to 9.8 g / d, (3) an elongation of 12% to 12.8%, (4) a birefringence index of 0.30 to 0.45, Density, (6) shrinkage of 6.2 to 7.1% The radial pneumatic tire according to claim 1, wherein the carcass ply is used as one or two layers, and the dipped cord reinforcing density is 20 to 40 EPI. The radial pneumatic tire according to claim 1, wherein the dip cord has a twist number of 300 to 500 TPM. The radial pneumatic tire according to claim 1, wherein the dipped cord has an E2.25 (elongation at 2.25 g / d) + FS (free shrinkage) of not less than 0 and not more than 6.5%.

Images