KR20050094681A - Pneumatic tire with steel capply - Google Patents

Abstract

According to the present invention, in the pneumatic tire to which the cap ply is applied to the belt layer, the cord applied to the cap ply is a microfiber steel cord, and the microfiber steel cord has a filament thickness of 0.07 mm to 0.14 mm and a carbon content of 0.70 parts by weight to It is characterized by being 0.95 parts by weight.

As described above, the cords applied to the cap plies (full cap plies, edge cap plies, etc.) of the tires may be made of microfiber steel cords instead of the conventional nylon-66, thereby improving tire durability, uniformity, and sensory index. .

Description

Pneumatic tire with steel capply}

The present invention relates to a pneumatic tire to which the cap ply is applied to the belt layer, and more particularly to the pneumatic tire to improve tire durability and uniformity performance by using a microfiber steel cord instead of nylon-66. It's about tires.

In recent years, high-speed driving is frequently performed according to the luxury of passenger cars and the development of roads, and thus, the stability and high-speed durability of tires have become very important.

In particular, in the tire having a low flat ratio, the above performances are more important, and a cap ply is applied to the upper portion of the belt layer in order to design such an excellent performance.

For high speed performance of the tire, not only the tensile strength of the cord should be excellent, but also the shrinkage of the cord material should be low for excellent tire uniformity performance.

Conventionally, nylon-66 was applied as the code material of the cap ply.

The nylon-66 has excellent tensile strength, but has a problem in that the shrinkage ratio is large, resulting in poor uniformity performance.

Thus, various methods for improving the problem of falling performance of the above-described uniformity have been proposed.

Among them, there is a Japanese patent publication (Publication No. 10-1994-032110), which relates to a method for improving a capply application method.

Looking at the method in more detail, the cap ply is made so that the fiber cord is embedded in the longitudinal direction in a rubber sheet about 10 mm wide. The cap ply manufactured as described above is wound symmetrically around both ends of the belt, and the winding method includes a method of winding from the inside of the belt to the outside or from the outside to the inside.

The cap fly wound as described above is wound in a tire circumferentially inclined state, and when the lift is applied in the vulcanization process, the change in the belt width becomes uneven to the tire circumference, resulting in poor uniformity.

The Japanese Laid-Open Patent could improve the problem, that is, the fall of the uniformity of the tire by improving the cap fly-winding method.

However, the Japanese Laid-open Patent still remains a problem of causing tire deformation during vulcanization due to shrinkage of the fiber cord used in the capply rubber sheet. The most widely used material for the cap fly fiber cord is nylon-66 cord, and the cord has a problem of causing a change in belt width due to large shrinkage during vulcanization.

The present invention has been made to solve the above problems, the purpose of the tire is applied to the cap ply (full cap ply and edge cap ply, etc.) of the fine-fiber steel cord instead of nylon-66, the durability of the tire To improve uniformity and sensory index.

In order to achieve the above object, the present invention provides a pneumatic tire to which a cap ply is applied to a belt layer. The cord applied to the cap ply is a microfiber steel cord, and the microfiber steel cord has a thickness of 0.07 mm to 0.14 mm, and carbon It is characterized in that the content is 0.70 parts by weight to 0.95 parts by weight.

The microfiber steel cord may have a tensile strength of 25 kgf to 29 kgf, and a cord thickness of 0.34 mm to 0.40 mm, particularly if there is no thermal contraction rate.

The structure of the microfiber steel cord is 1 + 5 + 10 * 0.1, 7 * 3 * 0.08, 2 + 7 + 11 * 0.08, 4 + 10 * 0.1, 1 * a + 6 * a (a = 0.06 ~ 0.14mm ), 12 * b (b = 0.06 ~ 0.13mm), 1 * c + 0.18 * c (c = 0.06 ~ 0.13mm).

In the steel cord according to the present invention, the carbon content of the filament is preferably 0.70 parts by weight to 0.95 parts by weight.

Looking at the type of tensyl corresponding to the carbon content is as follows.

First, there is normal tensile having a carbon content of 0.70 to 0.75 of the filament of the steel cord. In the present invention, the carbon content of the normal tensyl is most preferably 0.72 parts by weight.

Second, there is a high tensile having a carbon content of 0.80 to 0.85 of the filament of the steel cord. In the present invention, the carbon content of the high tensil is most preferably 0.82 parts by weight.

Third, there is a super high tensile having a carbon content of 0.86 to 0.89 of the filament of the steel cord. In the present invention, the carbon content of the super high tensyl is most preferably 0.86 parts by weight.

Fourth, there is an ultra high tensile having a carbon content of 0.90 to 0.94 of the filament of the steel cord. In the present invention, the ultra high tensyl carbon content is most preferably 0.92 parts by weight.

In the microfiber steel cord, when the carbon content of the filament is less than 0.70 parts by weight, there is a problem that the strength of the cap ply reinforcement is not sufficient or the weight is excessively increased, and when the carbon content of the filament exceeds 0.95 parts by weight, the diameter ( When φ) is drawn to a microfiber of 0.14 mm or less, a problem arises that the disconnection rate increases rapidly and becomes difficult to industrialize. Therefore, in the present invention, the filament thickness of the microfiber steel cord is preferably 0.07 mm to 0.14 mm.

In the microfiber steel cord, when the filament thickness is less than 0.07 mm, the cutting strength of the filament is lower than the friction force when the wire is drawn. Therefore, the disconnection is increased. In the present invention, since the fatigue fatigue performance is rapidly reduced in fatigue stress conditions, the thickness of the filament of the microfiber steel cord is preferably 0.07 mm to 0.14 mm.

Table 1 compares the code physical properties used in the prior art and the present invention.

<Table 1> Code Property Comparison by Material

Item Nylon -66 (8400D / 2P) twist = 32tpi Steel cord (1 * 0.13 + 6 * 0.12ht) Tensile strength (kgf) 15 27 Cord thickness (mm) 0.52 0.37 Modulus of elasticity (GPa) 0.9 to 1.0 3.1 to 3.5 Heat Shrinkage (%) (177 ° C × 2min, 84g) 5.5 0

With reference to Figure 1 will be described the physical properties of the cord applied to the cap ply of the tire. Here, nylon-66 was used in the conventional invention, and steel cord was used in the present invention.

First, looking at the tensile strength of the same diameter of the cord, the present invention (steel cord) is about twice as compared to the conventional invention (nylon-66). Accordingly, the present invention can lower the cost of the code.

Second, steel cords are thinner than nylon-66, making the capply rubber topping gauge significantly lower than conventional materials. Accordingly, the tire of the present invention can reduce the weight of the conventional tire, it is advantageous in terms of tire durability as the heat release is advantageous when running the tire.

Third, the steel cord has a higher elastic modulus than that of nylon-66, thereby minimizing a standing wave phenomenon when the tire is running. Accordingly, the present invention can improve tire steering stability and durability.

Fourth, compared to nylon-66, steel cord has no heat shrinkage at high temperature, thereby improving tire uniformity.

Hereinafter, the present invention will be described by the following comparative examples and examples. However, these do not limit the technical scope of the present invention.

Comparative Example 1

As shown in Table 2, the cord structure is 840D / 2P, and one piece of nylon-66 with a cord array density (EPI) of 30 is applied to a full cap ply of a tire 235 / 40R 17ZR standard so that the top gauge is 1.0 mm. Durability, uniformity, steering stability (sensor index) and dimensional nonuniformity were measured, and the results are summarized in Table 4 below.

<Example 1>

As shown in Table 2, the cord structure is 1 * 0.13 + 6 * 0.12ht, and the steel cord with cord array density (EPI) of 16 is attached to the tire 235 / 40R 17ZR full cap ply so that the top gauge is 0.7mm. Chapter 1 was applied to measure the durability performance, uniformity, control stability (sensor index) and dimensional non-uniformity, and the results are summarized in Table 4 below.

Comparative Example 2

As shown in Table 3, the cord structure is 840D / 2P, and two sheets of nylon-66 with a cord array density (EPI) of 30 are applied to the edge cap ply of the tire 205 / 55R 15VR standard so that the top gauge is 1.0 mm. The durability performance, uniformity, control stability (sensor index), dimensional nonuniformity was measured, and the results are summarized in Table 5 below.

<Example 2>

As shown in Table 3, the cord structure is 1 * 0.13 + 6 * 0.12ht, and the steel ply with cord array density (EPI) of 16 is placed on the edge ply of tire 205 / 55R 15VR standard so that the top gauge is 0.7mm. Chapter 1 was applied to measure the durability performance, uniformity, control stability (sensor index) and dimensional non-uniformity, and the results are summarized in Table 5 below.

Table 2 Code Specifications Used in Comparative Example 1 and Example 1

Item Comparative Example 1 Example 1 Code material Nylon-66 steal Code structure 840D / 2P 1 * 0.13 + 6 * 0.12ht EPI (Array Density) 30 16 Topping Gauge 1.0mm 0.7mm How to apply cap fly 1 full CAP 1 full CAP

Table 3 Code Specifications Used in Comparative Example 2 and Example 2

Item Comparative Example 2 Example 2 Code material Nylon-66 steal Code structure 840D / 2P 1 * 0.13 + 6 * 0.12ht EPI (Array Density) 30 16 Topping Gauge 1.0mm 0.7mm How to apply cap fly Edge CAP 2 Chapter One Edge CAP

<Test Example>

The cords of Comparative Examples and Examples were tested for durability, uniformity, and sensory index of cap plies (full cap plies and edge cap plies) of each tire standard, and the results are summarized in Tables 4 and 5 below. Indicated.

Table 4 Test Results of Comparative Example 1 and Example 1

Item Comparative Example 1 Example 1 Code material Nylon-66 steal Durability (ECER-30) 1 hour 30 minutes 2 hours 10 minutes Sensory index 6.0 7.5 Radial run-out 1.2 mm 0.8mm

TABLE 5 Test results of Comparative Example 2 and Example 2

Item Comparative Example 2 Example 2 Code material Nylon-66 steal Durability (ECER-30) 1 hour 22 minutes 1 hour 54 minutes Sensory index 5.5 6.5 Radial run-out 1.2 mm 0.8mm

* ECER-30: European tire durability standard test method.

** The smaller the radial run-out (RRO) value, the better the uniformity performance (uniformity).

As can be seen from the result of the test example, the cord applied to the tire cap ply (full cap ply and edge cap ply, etc.) is used as a microfiber steel cord instead of the conventional nylon-66 to improve the durability, uniformity and sensory index of the tire. Can be improved.

Claims (3)

In a pneumatic tire having a cap ply applied to the belt layer, the cord applied to the cap ply is a microfiber steel cord, and the microfiber steel cord has a filament thickness of 0.07 mm to 0.14 mm and a carbon content of 0.70 part by weight to 0.95 part by weight. Pneumatic tire, characterized in that. The pneumatic tire according to claim 1, wherein the microfiber steel cord has a tensile strength of 25 kgf to 29 kgf and a cord thickness of 0.34 mm to 0.40 mm. The microfiber steel cord has a structure of 1 + 5 + 10 * 0.1, 7 * 3 * 0.08, 2 + 7 + 11 * 0.08, 4 + 10 * 0.1, 1 * a + 6 *. A pneumatic tire comprising a (a = 0.06 to 0.14 mm), 12 * b (b = 0.06 to 0.13 mm), and 1 * c + 0.18 * c (c = 0.06 to 0.13 mm).