KR20170090689A

KR20170090689A - The Radial Tire for Passenger Car

Info

Publication number: KR20170090689A
Application number: KR1020160011358A
Authority: KR
Inventors: 이경하; 우진; 박진경; 남윤희
Original assignee: 주식회사 효성
Priority date: 2016-01-29
Filing date: 2016-01-29
Publication date: 2017-08-08

Abstract

Disclosed is a radial pneumatic tire having a flatness ratio of 0.65 or less, comprising a pair of parallel bead cores, at least one radial carcass layer wound around the bead cores, a belt layer laminated on the outer circumferential side of the carcass layer, and a circumferential cap ply formed on the outer circumferential side of the belt layer. The cap ply has two layers wherein aramid cords are located within a circumference and nylon 66 cords are located in an upper part of the aramid cords in the form of enveloping all or part of the aramid cords. The radial tire of the present invention overcomes the disadvantage conventional nylon 66 fibers may cause by forming standing waves at high speed due to a low modulus and cause flat spots. As a result, the radial tire of the present invention may maintain high shape stability and high steering performance at high temperature and reduce the incidence of flat spots.

Description

[0001] The Radial Tire for Passenger Car [0002]

The present invention relates to a radial pneumatic tire having a flatness ratio of 0.65 or less, wherein the layer of the cap ply is made of two layers so that the aramid cord is located inside the circumference, and the nylon 66 cord encapsulates the aramid cord in whole or in part, And a radial tire for a passenger car manufactured by being positioned at an upper portion of a cord.

In recent years, the performance of tires has been continuously improved according to improvement of the road environment and the performance of the vehicle. Especially, as the weight of the vehicle increases and the speed of the vehicle increases, safety is regarded as an important factor for the tires. In order to meet such a demand for increasing safety of tires, a method of imparting cap ply to a tire for a passenger car has been widely used as a method for imparting safety to a tire. Particularly recently, such a cap ply tire has been generalized and widely applied In fact. The cap ply is a part between the tire tread and the part and the steel cord layer for reinforcing the belt continuously wound continuously in the circumferential direction of the tire to maintain the shape stability of the tire. Especially, It is generally reinforced. When the vehicle travels, a load is applied in the axial direction of the tire cord, and the tire cord is repeatedly deformed and restored in the axial direction by the load. In this deformation-recovery, the tensile- The curve occurs along the other curve, where the tire cord itself is lost due to the difference in the recovery curve when the strain due to the tensile load and the load are removed. This work loss contributes to a rise in the temperature of the tire and the tire cord. In addition, since the tire rotates due to this work loss, energy loss occurs during running. This energy loss leads to the rotation resistance of the vehicle. In general, when a material having a characteristic of energy loss is used, an increase in the fuel economy of the vehicle due to an increase in the rotational resistance of the tire and a rise in temperature of the tire due to traveling do. The role of the cap ply material is to prevent the size of the tire from increasing during travel as the cap ply shrinks when the temperature of the tire rises due to vehicle travel. In this case, since the size of the tire is not increased, the increase in the rotational inertia of the tire is prevented. As a result, the energy consumption is reduced and the heat generation of the tire is suppressed, thereby increasing the fatigue life and increasing the durability.

In general, the most widely used material for cap-ply materials is nylon 66, which is known to be due to the high shrinkage of nylon 66. The portion where the cap ply is reinforced is known as the portion where the temperature is highest during running in the tire. In addition to the heat shrinkage force, a material having heat resistance, that is, a property of lowering the physical properties due to heat is required. In addition, Materials must be used. Nylon 66 is the material used for tire cords with these properties. Researches are also under way to apply to cap ply using other materials such as PET and PEN. However, these materials are weak to heat, and in particular, there is a limit to the application to cap ply because of the large deterioration of adhesion due to heat.

Other materials used for cap fly include aramid, but the use of aramid has different characteristics than using nylon 66. An aramid fiber is an aromatic polyamide fiber, which is a polyamide fiber having a benzene ring in a repeating unit. It is a material that shows stable physical properties even at high temperatures. When applied to tire cap ply, it can not be expected to exhibit shrinking force at high temperatures. However, since the deterioration of physical properties is extremely low even at high temperatures, the deformation itself is suppressed and is similar to the result of applying nylon 66 cap ply It has the characteristic of acting. Therefore, the use of such aramid fibers is also increasing.

Korean Patent Publication No. 10-1205944 Korean Patent Publication No. 10-2013-0079257 Korean Patent Publication No. 10-2014-0028711 Japanese Patent Application Laid-Open No. 2003-516263

The present invention relates to a radial tire in which conventional nylon 66 fibers and aramid fibers are applied to a cap ply. In applying the nylon 66 and aramid cords to a cap ply, an aramid cord is placed on the inside of the circumference, Thereby improving the steering stability and riding comfort of the tire, and improving the shape stability at the time of high-speed traveling.

In order to achieve the above object, the present invention provides a radial pneumatic tire having a flatness ratio of 0.65 or less, comprising: a pair of parallel bead cores; at least one radial carcass layer wound around the bead cores; And a cap ply in a circumferential direction formed on an outer circumferential side of the belt layer, wherein the cap ply layer has a two-layer structure in which an aramid cord is positioned inside a circumference, The radial pneumatic tire is manufactured by placing the pneumatic tire at the upper part of the aramid cord in the form of wrapping all or part of the cord.

Further, in the present invention, it is preferable that the carcass layer is a polyethylene terephthalate dip cord.

Further, in the present invention, it is preferable that the nylon 66 cord is 1260d / 2p and the aramid cord is 1000d / 2p.

In the present invention, the cap ply has two layers, the aramid cords are located inside the circumference, and the nylon 66 cords are located in the upper part of the aramid cords in the form of wrapping all or part of the aramid cords, Standing wave phenomenon can occur at high speed due to low modulus. It can overcome the disadvantage that it can cause flat spot, so it can maintain high shape stability, high handling performance at high temperature and reduce flat spot phenomenon.

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. .

Fig. 1 shows a structure of a tire for a passenger car.

The nylon 66 yarn and the aramid yarn for the production of the dip-cord-use dipped cord according to the present invention can be produced through the following processes.

First, the nylon 66 high-strength fiber used in the present invention will be described in detail. The nylon 66 high-strength fiber is obtained by spinning a melt of Nylon 66 melted in an extruder, spinning it, passing it through a multistage roller, Can be manufactured by a spin-draw process.

In the case of producing a nylon 66 high-strength yarn by the spin-draw method, a nylon 66 copolymer chip having a relative sulfuric acid viscosity of 2.7 to 3.4 was melted in an extruder and transferred to a spinneret through a gear pump. Then, an emulsion is applied using an emulsion applying device, and the emulsion is radiated at a spinning speed of 400 to 1,000 m / min, and then stretched, heat fixed, and relaxed while passing through a plurality of pairs of high-defect rollers. At this time, the free draw ratio between the first and second high-deflection rollers and the second high-deflection roller is 1.01 to 1.08, the first-stage stretching ratio between the second and third high-deflection rollers is 2.5 to 3.5, The stretching ratio between the rollers and the fourth felt rollers is 1.5 to 2.5, the total stretching ratio is adjusted to a level of 4.0 to 6.0, and the stretching ratio is adjusted to a level of 0 to 6% at a speed of 2,500 to 4,000 m / min . The temperature of the first high detent roller is at room temperature, the temperature of the second high detent roller is in a range of from room temperature to 90 DEG C, the temperature of the third high detent roller is in a range of 120 to 200 DEG C, the temperature of the fourth high detent roller is in a range of 180 to 230 DEG C, It is preferable that the temperature of the fifth high deterioration roller is from room temperature to 150 deg.

Here, the elasticity of the broken portion is set to 40 g / d or less by setting the relaxation rate to 4 to 5% in the yarn manufacturing process and the relaxation temperature to 240 to 280 ° C. Since the tenacity of the yarn is closely related to the slope of the yarn breakage region, it is preferable to fabricate the nylon 66 high strength fiber so that the modulus of elasticity at the breaking site is 40 d / g or less. If the relaxation rate is less than 4% or the relaxation temperature range is less than 240 ° C, the strength decreases, and when the relaxation rate exceeds 5% or the relaxation temperature range exceeds 280 ° C, there arises a problem that the radiation workability deteriorates .

Next, the method for producing the aramid yarn used in the present invention will be described in detail.

An aromatic polyamide polymer can be prepared by polymerizing an aromatic diamine and a dicarboxylic acid halide.

The aromatic diamines that can be used in the present invention include aromatic diamines such as paraphenylenediamine, 4,4-diaminobiphenyl, 2-methyl-paraphenylenediamine, 2-chloropaphenylenediamine, 2,6- 5-naphthalene diamine, 4,4-diaminobenzanilide, and the like, but it is preferable to use p-phenylenediamine.

In addition, the aromatic dicarboxylic acid halide may be at least one selected from the group consisting of terephthaloyl chloride (TPC), 4,4-benzoyl chloride, 2-chloroterephthaloyl chloride, 2,5-dichloroterephthaloyl chloride, , 2,6-naphthalenecarboxylic acid chloride, 1,5-naphthalenecarboxylic acid chloride, and the like, but terephthaloyl chloride is preferably used.

In the present invention, an aromatic polyamide polymer having an intrinsic viscosity (I.V.) of 5.5 to 7.0 prepared by low temperature polycondensation of p-phenylenediamine and terephthaloyl chloride is used. If it is less than 5.5, the strength of the fiber decreases. If it exceeds 7.0, the solubility decreases.

Wet, dry, dry and wet spinning can be used, but it is possible to manufacture aromatic polyamide fibers with a uniform structure in dry-wet spinning, so that it is possible to manufacture high strength fibers.

The dry wet spinning process according to the present invention will be described in detail. When the aromatic polyamide solution is quantitatively supplied from the gear pump, the spinning stock solution discharged through the spinning nozzle passes through the air layer in the vertical direction and reaches the interface of the coagulating solution . The shape of the spinning nozzle used is usually circular. Considering the tire cord and industrial use in terms of application, considering the nozzle spacing for uniform cooling of the solution, the number of nozzles is preferably 200 to 1,500.

In the present invention, the hole interval of the spinneret is preferably 1.1 to 1.4 mm, more preferably 1.3 to 1.4 mm. If the hole spacing is less than 1.1 mm, the filaments are closely adhered to each other during high-speed spinning to deteriorate the physical properties. If the hole spacing is more than 1.4 mm, the diameter of the spinneret increases.

In the present invention, the spinning speed is preferably 300 to 1,200 m / min. If the spinning speed is less than 300 m / min, the productivity deteriorates. If the spinning speed exceeds 1,200 m / min, the properties of the filament deteriorate sharply.

When the fiber stock solution passing through the spinning nozzle coagulates in the coagulating solution, the larger the diameter of the fluid becomes, the greater the difference in the coagulation speed between the surface and the inside becomes, so that it becomes difficult to obtain a dense and uniform tissue fiber. Therefore, when the aromatic polyamide solution is spun, even if the same discharge amount is maintained, a fiber having a smaller diameter can be obtained in the coagulating solution by keeping an appropriate air layer. It is difficult to increase the spinning speed because the too short air layer distance increases the micropore generation rate due to the rapid surface layer coagulation and desolvation process, and it is difficult to increase the spinning speed. On the other hand, the too long air layer distance is affected by the adhesion of the filament, It is difficult to maintain process safety by receiving large amounts. The air layer is preferably 3 to 20 mm.

(Twisting process) in which a cord is twisted with a nylon-66 yarn and an aramid yarn manufactured by the above-described method, respectively.

The softened tire cord manufactured by the present invention can be manufactured at 300/300 TPM to 500/500 TPM at the same time as the upper / lower tires, and the upper and lower tires are given the same numerical values, It is easy to maintain a straight line image without showing twist and the like so as to maximize physical property manifestation. If it is less than 300/300 TPM, the output of the live cord is reduced and the fatigue resistance is likely to decrease. On the other hand, if it exceeds 500/500 TPM, the strength drop is too large to be suitable for tire cords.

The produced raw cord is woven using a weaving machine, and the obtained fabric is dipped and cured in the dipping solution to produce a dip cord for a tire cord to which a resin layer is attached to the raw cord surface.

In the manufacturing process according to the present invention, dipping refers to impregnating a resin layer called RFL (Resorcinol-Formaline-Latex) on the surface of the fiber. The dipping process is carried out in order to improve the disadvantage of the tire cord fabric which has poor adhesion to rubber.

In the present invention, an adhesive liquid for bonding a cap plastic cord and rubber can be manufactured by the following method.

Method of manufacturing adhesive liquid

29.4 wt% Resocinol 45.6 parts by weight; 255.5 parts by weight of distilled water; 37% formalin 20 parts by weight; And 3.8 parts by weight of 10 wt% sodium hydroxide was prepared and reacted at 25 DEG C for 5 hours with stirring, and the following components were added.

Next, 300 parts by weight of 40 wt% VP-latex; 129 parts by weight of distilled water; And 23.8 parts by weight of 28% ammonia water were added thereto, followed by aging at 25 DEG C for 20 hours to maintain the solid content concentration at 19.05%.

The adhesive liquid is applied after drying the cappla usage cord. In order to control the amount of adhesion of the adhesive liquid, the cappella cord is stretched to 1 to 5%, preferably 2 to 4%. If the elongation percentage is too high, the adhesion amount of the adhesive liquid can be adjusted but the yield is reduced and the fatigue resistance is reduced as a result. On the other hand, when the elongation percentage is too low, for example, when the elongation ratio is lowered to less than 1%, it is impossible to adjust the amount of dephosphorization due to penetration of the dipping liquid into the cord.

The adhesion amount of the adhesive is preferably 4 to 6% based on the weight of the fibers based on the solid content. After passing through the adhesive solution, the dip cords using Capra are dried at 120-150 ° C. The drying is carried out for 180 seconds to 220 seconds, and the dip-cord for dip coating can be stretched to about 1 to 2% in the drying process. If the elongation ratio is low, the cords and the cord of the cord increase, which may result in a property that is difficult to apply to the tire cord. On the other hand, if the elongation ratio is more than 2%, the level of the medium is adequate but the turnover is too small and fatigue can be reduced.

After drying, heat treatment is performed at a temperature range of 130 to 240 캜. The stretching ratio in the heat treatment may be -2 to 0%, and the heat treatment time is preferably 50 to 90 seconds. If the heat treatment is performed for less than 50 seconds, the reaction time of the adhesive solution is insufficient and the adhesive force is lowered. If the heat treatment is performed for more than 90 seconds, the hardness of the adhesive solution becomes high and the fatigue resistance of the cord may be decreased have.

The nylon 66 and aramid dipped cord produced through this process is applied to two layers of cap ply and is used for the manufacture of tires for passenger cars.

Fig. 1 shows a structure of a tire for a passenger car.

1, the bead region 35 of the tire 31 becomes an annular bead core 36 which is non-stretchable. The bead core 36 is preferably made of a single filament wire wound continuously. Preferably, a high strength steel wire having a diameter of 0.95 mm to 1.00 mm may be formed in a 4x4 structure or a 4x5 structure.

In an embodiment of the tire cord according to the present invention, the bead region 35 may have a bead filler 37, the bead filler 37 should have a hardness above a certain level, preferably a Shore A hardness Shore A hardness) Hardness of 40 or more.

According to the invention, the crown portion can be reinforced by the belt structure 38 and the cap ply 39. The belt structure 38 includes a cut belt ply 40 comprised of two belt cords 41 and 42 and the belt cords 41 of the belt ply 40 comprise about 20 Lt; / RTI > One belt cord 41 of the belt ply 40 may be disposed opposite the direction of the belt cord 42 of the other belt ply 40 in a direction opposite the circumferential center plane. However, the belt structure 38 may comprise any number of ply. The belt structure 38 serves to provide lateral stiffness to minimize the rise of the tread 33 from the road surface during operation of the tire 31. [ The belt cords 41, 42 of the belt structure 38 can be made of steel cords and have a 2 + 2 structure, but can be made of any structure. The cap ply 39 and the edge ply 44 are reinforced on the upper portion of the belt structure 38 so that the cap ply cords 45 of the cap ply 39 are reinforced in parallel with the circumferential direction of the tire, The cap ply cords 45 of the cap ply 39 having a large heat shrinking stress at a high temperature are used. The cap ply 39 of the present invention has two layers, the aramid cord is located inside the circumference, and the nylon 66 cord is placed in the upper part of the aramid cord in such a manner that the aramid cord is entirely or partially enclosed. The present invention relates to radial tires for passenger cars.

Reference numerals 32 and 34, which are not illustrated in FIG. 1, represent the carcass layer 32 and the fly turn 34. And reference numeral 33 denotes a carcass layer reinforcing cord 33. [

Hereinafter, the structure and effects of the present invention will be described in more detail with reference to examples.

[Example 1]

Nylon 66 yarn and aramid yarn were respectively obtained according to the above-described method for producing tire reinforcing fibers.

Twisted twist yarns were prepared by applying twist of 450 TPM to two nylon 66 yarns (1,260D), and the twist yarns were folded in two, and the twist yarns were stitched with 450 TPM to produce a cord. The obtained nylon 66 raw cord was dried at 100 캜 for 130 seconds, and then passed through an adhesive liquid prepared by the following method to give an adhesive liquid. A 2% stretch was applied during drying to prevent unevenness of raw cord due to heat shrinkage.

Twisted twist yarns were prepared by applying twist of 450 TPM to each of two aramid yarns (1,000 D), and the twist yarns were folded in two, and the yarns were streaked at 450 TPM to produce a cord. The obtained aramid cord was dried at 100 DEG C for 130 seconds, and then passed through an adhesive liquid prepared by the following method to give an adhesive liquid. A 2% stretch was applied during drying to prevent unevenness of raw cord due to heat shrinkage.

Method of manufacturing adhesive liquid

29.4 wt% Resocinol 45.6 parts by weight; 255.5 parts by weight of distilled water; 37% formalin 20 parts by weight; And 3.8 parts by weight of 10 wt% sodium hydroxide was prepared and reacted at 25 DEG C for 5 hours with stirring, and the following components were added. Next, 300 parts by weight of 40 wt% VP-latex; 129 parts by weight of distilled water; And 23.8 parts by weight of 28% ammonia water were added thereto, followed by aging at 25 DEG C for 20 hours to maintain the solid content concentration at 19.05%.

[Comparative Example 1]

The raw cord and treated cord were prepared in the same manner as in the above example, except that the nylon 66 yarn was twisted at 1,260 denier / twin.

[Comparative Example 2]

The raw cord and treated cord were prepared in the same manner as in the above example, except that aramid yarn was spun at 1,000 denier / two.

The dip cords prepared according to Example 1 and Comparative Examples 1 and 2 were used in the cap ply layers of the tires as shown in Table 1 to produce 215/65 R16 V tires. The tires were mounted on a 2000cc class passenger car, and a skilled driver ran the test course, and the stability and ride comfort were evaluated on a scale of 100 points to 5 points. The results are shown in Table 1 below. The durability was measured according to the FMVSS (Federal Motor Vehicle Safety Standard) according to the 109 P-metric tire endurance test method at a temperature of 38 ° C (° C) , 90%, 100%, running at a speed of 80 km / h for a total of 34 hours to show signs of bead separation, cord cutting, belt separation, etc. on any part such as tread, sidewall, carcass cord, inner liner, If it can not be found, it is judged as OK (OK).

Comparative Example 1 Comparative Example 2 Example One Tire Kakas PET 1,500D / 2 PET 1,500D / 2 PET 1,500D / 2 Cap fly Nylon 1,260D / 2 Aramid 1,000D / 2 Nylon 1,260D / 2
Aramid 1,000D / 2 Flat rate 0.6 0.6 0.6 Number of carcass layers One One One Cap fly layer number 2 One 2 Ride comfort 90 95 100 Steering stability 90 100 100 durability OK OK OK Uniformity 88 93 100

As a result of the test shown in Table 1, the cap ply according to the present invention has two layers, the aramid cords are located inside the circumference, and the nylon 66 cords encircle all or part of the aramid cords. It can be seen that the performance of the tire manufactured in the upper layer (Example 1) in terms of ride comfort, steering stability, and uniformity is improved compared to Comparative Example 1 in which only the nylon 66 cord is used for the cap ply, 2, the performance in terms of ride comfort and unity is improved.

31: Tire 32: Carcass layer
33: Carcass layer reinforcement cord 34: Fly turn-up
35: bead region 36: bead core
37: bead filler 38: belt structure
39: cap fly 40: belt fly
41, 42: belt cord 43: tread
44: edge fly 45: cap fly cord

Claims

1. A radial pneumatic tire having a flatness ratio of 0.65 or less, comprising: a pair of parallel bead cores; at least one radial carcass layer wound around the bead cores; a belt layer laminated on the outer circumferential side of the carcass layer; And a circumferential cap ply formed on an outer peripheral side of the cap ply,
Characterized in that the cap ply has two layers and the aramid cords are located inside the circumference and the nylon 66 cords are located in the upper part of the aramid cords in the form of enveloping all or part of the aramid cords. tire.

The method according to claim 1,
Wherein the carcass layer is a polyethylene terephthalate dip cord.

The method according to claim 1,
Wherein the nylon 66 cord is 1260d / 2p and the aramid cord is 1000d / 2p.