KR101041670B1 - Hybrid Cord for Tire Reinforcing Belt and Air Injection Tire Comprising The Same - Google Patents

Abstract

The present invention relates to a hybrid cord for a tire reinforcement belt and a pneumatic tire including the same, more particularly, comprising a high modulus code and a low modulus code and having a final tangent coefficient / initial tangent. The present invention relates to a hybrid cord for a tire reinforcing belt having a coefficient of 7 or more and a pneumatic tire including the same. The pneumatic tire to which the hybrid cord of the present invention is applied as a reinforcing belt simultaneously improves low-speed and high-speed endurance performance and steering stability. It has excellent characteristics.

Tire reinforcement belt, hybrid cord, high modulus, low modulus, breaking strength, heat resistance adhesion, pneumatic tire.

Description

Hybrid Cord for Tire Reinforcing Belt and Air Injection Tire Comprising The Same}

The present invention relates to a hybrid cord for tire reinforcement belts and pneumatic tires comprising the same, more particularly comprising a high modulus cord and a low modulus cord, the final tangent modulus / initial tangent The present invention relates to a hybrid cord for a tire reinforcing belt having a coefficient of 7 or more and a pneumatic tire including the same.

In general, typical performance demands of high-performance tires along with improved performance of the vehicle include high speed durability, steering stability, ride comfort, and noise.

In a tire, a belt is a very important factor that distributes the stress transmitted from the ground while driving and maintains the tire's grounding shape so that it has excellent driving, wear and braking performance. Particularly, the reinforcing belt catches the flow of the belt and maintains the optimum belt shape during driving so that the tire always maintains a good belt shape to have good tire performance.

The main characteristics required for the cord for the reinforcing belt is heat-resistant adhesion, shrinkage, modulus at room temperature and high temperature. Among these, the heat-resistance force is the property that is most relevant to the durability of the tire because it is located between the tread and the belt that generate the most heat in the tire due to the nature of the position where the reinforcing belt is used, and is subject to aging due to high temperature during driving. have.

In addition, modulus is generally a physical property highly correlated with ride comfort, steering stability, and the like. In other words, a tire cord with a large modulus plays an advantageous role in reducing the change in the shape of the belt due to the force transmitted from the outside, and the shape maintenance from the external force can maintain the performance of the originally designed tire. affect. In addition, if a high cutting force cord is simply used to reinforce the modulus, the tire may not absorb the shock while driving, and the vehicle may receive vibration and noise directly, thereby causing high stress to the driver.

Another factor that can affect the running performance of the tire is the heat generated when the tire is running. In general, all materials decrease in modulus with increasing temperature. The modulus of the reinforcement belt also decreases as the tire's running speed increases as the internal temperature increases.As the decrease in modulus at high temperatures leads to the deterioration of tire performance at high temperatures, it is very important to maintain the modulus at high temperatures. It can be said to be a required characteristic of.

In general, widely used cords for passenger car tires include rayon, polyethylene terephthalate (PET) and nylon. However, PET cords are disadvantageous in terms of heat-resistant adhesion and have a low modulus at high temperatures, making it difficult to use reinforcing belts. In addition, there is no shrinkage-related behavior in the case of rayon, and it is difficult to use the cord because it does not hold the belt due to the length of the cord rather at a high temperature. Meanwhile, the most widely used nylon currently uses nylon 66, which is more excellent in heat resistance than nylon 6. Nylon 66 is excellent in heat adhesiveness and exhibits low modulus at high temperatures compared to PET or nylon 6. As an advantage, it is the most reinforcing belt material used so far in the world. However, due to the nature of nylon, the basic modulus is very low, there is some limitation in terms of improved steering stability.

The present invention is to solve the problems of the prior art as described above, one object of the present invention is excellent in the heat-resistant adhesion, by improving the modulus at room temperature and the problem of lowering the modulus at high temperature, It is to provide a hybrid cord for tire reinforcement belt that can simultaneously improve the durability and steering stability at high speed.

Another object of the present invention is to provide a pneumatic tire having excellent low-speed and high-speed durability and steering stability and excellent ride comfort by applying the hybrid cord as described above to the tire reinforcing belt.

One aspect of the present invention for achieving the above object comprises a high modulus code and a low modulus code, the final tangent coefficient / initial tangent coefficient ratio of the hybrid cord for a tire reinforcement belt, characterized in that 7 or more It is about.

In the hybrid cord for a tire reinforcing belt according to an embodiment of the present invention, the high modulus cord has a breaking strength of 20 g / Denier or more, and the low modulus cord has a breaking strength of 2 g / Denier or more.

Another aspect of the present invention for achieving the above object relates to a pneumatic tire to which the hybrid cord of the present invention as described above is applied to a reinforcing belt.

The hybrid cord for a tire reinforcing belt according to the present invention and the pneumatic tire using the same have excellent heat resistance and improve the modulus at room temperature and the decrease in modulus at high temperature, thereby improving durability and steering stability at low and high speeds. At the same time there is an effect to improve.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings, examples, and the like.

1 is a cutaway view of a pneumatic tire according to one embodiment of the invention. Referring to FIG. 1, a pneumatic tire typically comprises a rubber layer 1, a reinforcing belt portion 2, belts 3 and 4 and a carcass portion 5.

The cord for a tire reinforcing belt according to an embodiment of the present invention is made of a hybrid code of a high modulus code-a low modulus code, and a final tangent coefficient / initial tangent coefficient ratio is 7 or more.

When the ratio of the final tangent coefficient / initial tangent coefficient is less than 7, the cord is too low, so that the driving performance such as uniformity is excellent when the tire is running, but the riding comfort is reduced due to the running noise of the tire.

The hybrid cord according to an embodiment of the present invention may be manufactured using different modulus cords in a cord twisting process, wherein the high modulus cord of the hybrid cord has a breaking strength of 20 g / Denier or more, and a low modulus cord It is preferable that it is 2 g / Denier or more.

If the breaking strength of the high modulus cord according to the embodiment of the present invention is less than 20 g / Denier, there is a problem that the impact on the tire performance is minimal when the hybrid cord is applied, if the breaking strength of the low modulus cord is less than 2 g / Denier The hybrid code is too short, so there is a performance problem.

In the hybrid code, the high modulus code and the low modulus code may each have a quantitative fineness of 500 to 5,000 denier, but is not limited thereto.

In the hybrid cord according to the embodiment of the present invention, the twist number of the high modulus cord and the low modulus cord is not particularly limited, but preferably has a twist number of 120 to 480 TPM.

If the number of twist is less than 120 TPM, there is a problem of deterioration of ride comfort and external shock absorption due to tire noise due to lower cutting elongation, and if more than 480 TPM, the multifilament of the twisted part between cords is broken due to excessive twisting, which lowers the cutting strength. There is this.

The high modulus code according to an embodiment of the present invention is not limited thereto, but any one of PBO (poly (p-phenylene-2,6-benzobisoxazole)), aramid, or carbon fiber It is preferable to use PBO. In addition, the low modulus cord may be any one of nylon 6, nylon 66, nylon 46, polyester, rayon, or lyocell, but is not limited thereto. It is good to use.

Another aspect of the invention relates to a pneumatic tire comprising the hybrid cord for the tire reinforcement belt.

The pneumatic tire to which the reinforcement belt made of the high modulus / low modulus hybrid cord according to the embodiment of the present invention is excellent in heat resistance and the hybrid cord of the reinforcement belt improves the modulus at room temperature and at high temperature while driving. By improving the modulus deterioration problem, the low speed and high speed endurance performance and the steering stability can be improved simultaneously.

The method of manufacturing a hybrid cord for a tire reinforcing belt according to an embodiment of the present invention may be manufactured by a conventional hybrid cord manufacturing method known in the art, and a schematic process thereof is as follows.

First, high modulus and low modulus drawn yarns are manufactured in separate processes, and high modulus drawn yarns and low modulus drawn yarns are produced in a tire cord drawing process, respectively. Then, the hybrid cord is manufactured by twisting, weaving and heat treatment under similar conditions as in the manufacture of a conventional tire cord.

There is a two-stage twisting method for twisting the lower stage and twisting the upper stage in two stages, and a method of manufacturing the cord in one stage, which manufactures the upper and lower edges in the same machine at one time. It is possible to increase the number of twists during the 1st stage of inferior work, and in case of applying the 1st stage continuous system, it is possible to manufacture the product by performing the pretreatment by the difference between the upper and lower edges by using another injector before the injector. It is possible. At this time, the number of twists of the high modulus stretched yarn and the low modulus stretched yarn is not particularly limited, but preferably has a twist number of 120 to 480 TPM.

 CS hybrid method according to an embodiment of the present invention may be applied to any of the two-step method and one-step method.

Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples. However, this is for the purpose of explanation and the present invention is not limited thereto.

Example

High modulus cord with break strength 21g / Denier PBO (poly (p-phenylene-2,6-benzobisoxazole)) and low modulus cord with break strength 8 g / Denier nylon 66 with twist 480 TPM 1: 1 ( D / 1) Weaved and subjected to heat treatment and heat treatment under conditions similar to those of conventional nylon cord fabrication to produce a hybrid cord (D / 2) having a final tangent / initial tangent coefficient of 8.

Comparative Example 1

Nylon 66 cord, which is currently commonly used, was used as Comparative Example 1.

Comparative Example 2

A hybrid cord was prepared in the same manner as in the example except that the final tangent / initial tangent coefficient was 5 .

Table 1 shows the results of the physical property experiments of Examples and Comparative Examples 1 and 2.

Table 1

Comparative Example 1 Comparative Example 2 Example Nylon 66 PBO hybrid PBO hybrid Hybrid code - PBO-Nylon 66 PBO-Nylon 66 Final Tangent / Initial Tangent Coefficient
(Hybrid cord) - 5 8 rescue 840 D / 2 PBO 840 D / 1 +
Nylon 66 840 D / 1 PBO 840 D / 1 +
Nylon 66 840 D / 1 Corpse%
(at 9.1kgf Load) Room temperature 14 ↓ 2.0 ↓ 2.2 ↓ 120 DEG C 16 ↑ 2.2 ↑ 2.3 ↑ Breaking strength (g / D)  8 ↑  14 ↑  14 ↑ Elongation at break (%) 15 ↑ 3.8 ↑ 4.3 ↑ Heat adhesive force (kg) 14 ↑ 13 ↑  13.5 ↑

Property evaluation

(1) breaking strength measurement

The force of the cord when the fracture occurs in the elongation test is divided by the quantitative fineness, and the test method is in accordance with ASTM D885.

(2) cutting elongation

The elongation at which fracture occurs when the cord is stretched and the test method is in accordance with ASTM D885.

(3) heat-resistant adhesion

Adhesion test specimen and test method according to H-test ASTM D4776, and after 4 hours aging at 180 ℃ in relation to the heat resistance was measured for adhesion.

As shown in the results of Table 1, when the modulus is lowered due to the rise of the temperature of the tire while driving, the elongation is increased, resulting in distortion of the tire and the like, resulting in inferior adjustment stability. The hybrid cord according to the present invention shows that the hybrid cord according to the present invention is superior to the hybrid cord according to the present invention, as compared to Comparative Example 1, in which the percentile at a normal temperature and 120 ° C. (at 9.1kgf Load) is a nylon cord. It can be seen that there is little change in the physical properties of the cord.

On the other hand, the heat-resistant adhesive strength related to the durability, the cord made of conventional nylon 66 (Comparative Example 1) and the PBO hybrid cord according to an embodiment of the present invention showed the same level of heat-resistant adhesive strength.

In addition, the pneumatic tire was manufactured in the configuration as shown in Table 2 by applying the code according to the above Examples and Comparative Examples.

[Table 2]

Comparative Example 1 Comparative Example 2 Example Tire specification 225 / 45ZR17 225 / 45ZR17 225 / 45ZR17 code Nylon 66 PBO hybrid PBO hybrid Final Tangent / Initial Tangent Coefficient
(Hybrid cord) - 5 8 Fiber structure 840 D / 2 PBO 840 D / 1 +
Nylon 66 840 D / 1 PBO 840 D / 1 +
Nylon 66 840 D / 1 Reinforcement Belt Layer Count 2 2 2 Reinforcement belt form Front cover
(Full Cover) Front cover
(Full Cover) Front cover
(Full Cover) Code array density 35 35 35

The high-speed driving durability evaluation (ECER 30) and the initial adjustment stability evaluation, the running stability evaluation after the high-speed driving of the pneumatic tire manufactured in the configuration as shown in Table 2, the results are shown in Table 3 below.

[Table 3]

Comparative Example 1 Comparative Example 2 Example Remarks Tire specification 225 / 45ZR17 225 / 45ZR17 225 / 45ZR17 High speed running durability 1 hour 55 minutes 2 hours 50 minutes 2 hours 51 minutes Adjustment stability (initial) 100 117 116 Adjustment stability
(After high speed driving) 75 114 114 Initial tire diameter 100 98 99 Tire diameter at high speeds (200km) 104 100 99 noise 100 * 103 95 Index conversion Ride 100 * 94 105 Index conversion Cloud resistance 100 * 98 93 Index conversion

* Noise Index: Excellent <100 * <Low

      * Steering stability and ride comfort: Experienced drivers take the test course and evaluate it based on 100.

As shown in the results of Table 3, the hybrid cord according to the embodiment of the present invention to which the PBO hybrid cord is applied to the reinforcing belt is excellent in high-speed running durability, low-speed and high-speed driving stability compared to conventional nylon cords. The results are shown.

On the other hand, in terms of noise and ride comfort, the hybrid cord of the present invention having a final tangent modulus / initial tangent modulus ratio of 8 has a more favorable result than Comparative Example 2 having a ratio of the existing nylon cord and final tangent modulus / initial tangent modulus of 5. This means that when the final / initial coefficient ratio is 8, the elongation of the hybrid cord increases due to the influence of the low modulus cord, resulting in higher shock absorption during external impact shock and less hard feeling during driving, resulting in better riding comfort. Tire noise is reduced.

1 is a partial cutaway view of a pneumatic tire according to one embodiment of the invention.

[Description of main part of drawing]

1: rubber layer, 2: reinforcing belt layer 3: belt layer

4: belt layer 5: carcass layer

Claims (7)

A hybrid cord for a tire reinforcement belt comprising a high modulus cord and a low modulus cord, The hybrid cord has a final tangent modulus / initial tangent modulus ratio of 7 or more, wherein the high modulus cord is selected from the group consisting of PBO, aramid, or carbon fiber, and the low modulus cord is nylon 6, nylon 66, nylon 46, poly The high modulus cord has a breaking strength of 20 g / Denier or more, and the low modulus cord has a breaking strength of 2 g / Denier or more. code. delete delete The hybrid cord of claim 1, wherein the high modulus cord is PBO and the low modulus cord is nylon 66. The hybrid cord for a tire reinforcing belt according to claim 1, wherein the high modulus cord and the low modulus cord each have a quantitative fineness of 500 to 4,000 denier. The hybrid cord for a tire reinforcing belt according to claim 1, wherein the high modulus cord and the low modulus cord each have a twist number of 140 to 480 TPM. A pneumatic tire, characterized by applying the hybrid cord of claim 1 to a reinforcing belt.

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