KR100591682B1 - Capply Cord of Pneumatic Tire for a Passenger Car - Google Patents

Abstract

Cap ply code of the pneumatic tire for a passenger car of the present invention is twisted number of polyethylene naphthalate (PEN): polyvinyl alcohol (PVA) in the ratio of 1: 1 to 2 to 1 to 2: 1 200 ~ 600TPM (Twist Per Meter) It is characterized by consisting of a composite fiber.

In addition, the present invention is characterized in that the code array density (EPI) of the cap ply is 10 to 40 per inch.

In addition, the present invention is characterized in that the polyethylene naphthalate and polyvinyl alcohol is 100 ~ 2000 denia (denia).

As described above, polyethylene naphthalate (PEN) having excellent structural stability and polyvinyl alcohol (PVA) having excellent adhesive performance and structural stability are twisted together to form a composite fiber, which is used as a cord for a cord cap of a tire. Significantly improved ride comfort with improved rubber-to-rubber adhesion, tire durability and uniformity performance.

Cap ply, polyethylene naphthalate, polyvinyl alcohol

Description

Cord fly cord for passenger car {Capply Cord of Pneumatic Tire for a Passenger Car}             

1 shows the molecular structure of polyethylene naphthalate (PEN) according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap fly cord for a pneumatic tire for a passenger car. In particular, polyethylene naphthalate (PEN) having excellent structural stability, adhesiveness, and structural stability in order to improve the durability and uniformity performance of the tire. The present invention relates to a cap fly cord for a pneumatic tire for a passenger car in which excellent polyvinyl alcohol (PVA) is twisted together to form a composite fiber.

In recent years, with high-speed driving in accordance with the luxury of passenger cars, high-speed driving stability and high-speed durability are also very important. In particular, in the tire having a low flat ratio, the above performance is more important, and in order to satisfy such performance, nylon 66 (hereinafter referred to as 'N-66 cord') is frequently applied as a cap fly material.

The low flat tire is generally applied to the cap fly code to design for excellent high-speed driving performance, the cap fly affects the radial run-out (RRO) and durability performance.

Looking at the existing patent for improving the uniformity, there is a Japanese Patent Application Publication (Patent Publication No. Hei 6-32110, the name of the invention: the structure of winding the belt reinforcement in the tire).

The contents of the Japanese Unexamined Patent are as follows.

The cap ply is embedded in the fiber cord in the longitudinal direction in a rubber sheet about 10 mm wide. In addition, the cap ply is wound symmetrically around both ends of the belt, and the winding method includes a method of winding from the inside to the outside or from the outside to the inside.

The cap ply wound as described above is wound in a tire circumferentially inclined state, and when the lift is applied in the vulcanization process, the belt width change becomes uneven to the circumferential tire circumference to improve the unwinding of the uniformity. Improved to be uniformly wound.

However, the Japanese Laid-Open Patent improves the tire uniformity by improving the method of winding the cap ply, but there is a problem of causing tire deformation during vulcanization due to shrinkage of the fiber cord used for the cap ply. That is, the most widely used material as a cap fly fiber cord is a nylon-66 cord, and the cord has a problem of changing the belt width due to large shrinkage during vulcanization.

In addition, looking at the existing patent for improving the durability, there is a Korean patent (patent registration number: 10-0372749-0000, tire cap fly cord consisting of polyethylene naphthalate-nylon).

Looking at the contents of the Korean registered patent, the cap fly code was improved by applying a composite cord consisting of a PEN code having excellent structural stability and a nylon having excellent adhesion. In this way, the durability is improved, but there is a limit to increase the uniformity performance by applying a nylon code with poor structural stability (high shrinkage).

For reference, referring to the chemical structure of the N-66 code, H- (HN- (CH ₂ ) ₄ -NH-CO- (CH ₂ ) ₆ )) CO) _N -OH.

The present invention has been made to solve the above problems, its purpose is to twist the polyethylene naphthalate (PEN) with excellent structural stability and polyvinyl alcohol (PVA) with excellent adhesion and structural stability into a composite fiber The present invention provides a pneumatic tire for a passenger car, which is formed and used as a cord for a tire cap fly, thereby improving tire durability and uniformity performance.

In order to achieve the above object, the cord for a cap ply of a pneumatic tire for a passenger car of the present invention has a twist number of polyethylene naphthalate (PEN): polyvinyl alcohol (PVA) at a ratio of 1: 1 to 2 to 1 to 2: 1. ~ 600TPM (Twist Per Meter) is characterized by consisting of a composite fiber.

In the above polyethylene naphthalate: polyvinyl alcohol composite fiber composition 1 to 2 polyvinyl alcohol per polyethylene naphthalate or 1 to 2 polyethylene naphthalate per polyvinyl alcohol If the number of fibers constituting more than three is because the structure is complex and the physical properties fall.

When the twisted number of the composite fiber is less than 200TPM, it is difficult to maintain the straightness of the cord when applying the low denia, and if the twisted number of the composite fiber exceeds 600TPM, it is not preferable because the physical properties are sharply decreased at the high denia.

In addition, the present invention is characterized in that the code array density (EPI) of the cap ply is 10 to 40 per inch.

If the code array density of the cap ply is applied to less than 20 EPI (End per inch) in the above, the code spacing is large and the code array becomes uniform when the tire is formed, which causes a problem of reducing tire uniformity. Application of a density in excess of 40 EPI (End per inch) is not preferable because the spacing between the cords is too narrow, which makes the tire manufacturing difficult.

In addition, the present invention is characterized in that the polyethylene naphthalate and polyvinyl alcohol is 100 ~ 2000 denia (denia).

Applying polyethylene naphthalate and polyvinyl alcohol to less than 100 denia in the above is too small for a tire cord use, the cost is greatly increased, and practical practical problems occur, and polyethylene naphthalate and polyvinyl are Application of alcohol in excess of 2000 denia (denia) is not preferable because the thickness of the cord is too large to cause a problem that the tire weight increases a lot.

Excellent structural stability in tire cap ply cord properties means less intermediate elongation and less shrinkage. In other words, the small middle elongation means that the resistance to tension is large, and growth can be suppressed during tire running, which is advantageous for durability. In addition, if the heat shrinkage rate is small, the deformation of the tire during tire vulcanization is reduced, which is advantageous for tire uniformity performance.

Referring to Figure 1, when looking at the molecular structure of polyethylene naphthalate (PEN), there are two benzene groups based on the polyester group is very excellent in the stability of the structure due to heat and tension, while the polyunsortic It is composed of ester group and benzene path, which is very unfavorable for adhesion

On the other hand, in the case of polyvinyl alcohol (PVA) cord, there are many alcohol groups in the unit molecule, which has a very advantageous structure for chemical adhesion, and also the structural stability due to heat and tension is also very excellent.

Therefore, in the present invention, a polyethylene naphthalate (PEN) -polyvinyl alcohol (PVA) composite fiber cord composed of polyethylene naphthalate (PEN) having excellent structural stability and polyvinyl alcohol (PVA) having excellent adhesion and structural stability is used. When applied to the cap ply, both polyethylenenaphthalate (PEN) and polyvinyl alcohol (PVA) are excellent cords in terms of structural stability. It can improve tire durability performance and uniformity performance.

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

Comparative Example 1

Twisted 1000 Denia PEN and 840 Denia Nylon (N-66 or N-6) with a twist of 300 TPM and an array density of 28 to produce a code for a cap fly code 1000D / 840D PEN-Nylon composite fiber cord, 195 / 50R The composite fiber cord was applied to a tire for a passenger car having 15 specifications with a full cap ply once to measure the strength, the median elongation, and the heat shrinkage. The results are summarized in Table 1 below.

<Example 1>

1000 Denia PEN and 1000 Denia PVA are twisted to have a twist of 300 TPM and an array density of 28, to manufacture a code for the cap fly code 1000D / 1000D PEN-PVA composite fiber cord, which is pulled on a tire for a passenger car having a 195 / 50R 15 specification. Applying the composite fiber cord as a cap ply once to measure the strength, medium elongation, heat shrinkage and summarized the results in Table 1 below.

Comparative Example 2

Twisted 1500 Denia PEN and 1260 Denia Nylon (N-66 or N-6) with a twist of 300 TPM and an array density of 28 to produce a code for a cap fly code 1500D / 1260 PEN-Nylon composite fiber cord, 215 / 45R The composite fiber cord was applied to a tire for a passenger car having 17 specifications with a full cap ply once to measure the strength, the median elongation, and the heat shrinkage. The results are summarized in Table 2 below.

<Example 2>

The 1500D / 1500D PEN-PVA composite fiber cord is manufactured by twisting 1500 Denia PEN and 1500 Denia PVA to 300TPM and having an array density of 28, and is applied to a passenger car tire having 215 / 45R 17 standard. Applying the composite fiber cord as a cap ply once to measure the strength, median elongation, heat shrinkage and summarized the results in Table 2 below.

<Table 1> Measurement results of the physical properties of Comparative Example 1 and Example 1

Item Comparative Example 1 Example 1 Strong (kg) 15.5 16.8 Medium elongation (4.5kg) (%) 3.5 2.5 Heat Shrinkage (%) (177 ℃ × 2min, free) 2.5 0.5

<Table 2> Measurement results of the physical properties of Comparative Example 2 and Examples 2,3

Item Comparative Example 1 Example 1 Strong (kg) 24.5 30.2 Medium elongation (6.8kg) (%) 6.5 3.5 Heat Shrinkage (%) (177 ℃ × 2min, free) 3.5 0.7

<Test Example 1>

The cords of Comparative Examples 1 and 1 were tested on the full-cap ply of the passenger car tire standard, and the adhesion between the cord and rubber, durability, and uniformity, and the results are summarized in Table 3 below. It is shown.

Table 3 Test Results of Comparative Example 1 and Example 1

Item Comparative Example 1 Example 1 Adhesive force (cord-rubber, H-TEST) 12.5 kg 14.2 kg Durability (ECER-30) 1 hour 30 minutes 1 hour 52 minutes Unity 100% 98%

Table 4 Test Results of Comparative Example 2 and Example 2

Item Comparative Example 2 Example 2 Adhesive force (cord-rubber, H-TEST) 18 kg 18.2kg Durability (ECER-30) 1 hour 40 minutes 1 hour 55 minutes Unity 100% 130%

* Adhesive force (H-TEST) is ASTM standard adhesion test standard method.

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

* The uniformity of Examples 1 and 2 is a relative percentage based on Comparative Examples 1 and 2.

As can be seen from the results of Tables 3 and 4, the adhesion between the cord and the rubber, durability, and uniformity (uniformity) can be seen that the Example is superior to the Comparative Example.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

As can be seen from the results of the test example, according to the present invention, polyethylene naphthalate (PEN) having excellent structural stability and polyvinyl alcohol (PVA) having excellent adhesive performance and structural stability are twisted together to form a composite fiber, which is a cap of a tire. As a fly cord, the adhesion between the cord and rubber, tire durability and uniformity have been greatly improved, resulting in a significantly improved ride comfort.

Claims (3)

In the cord for a cap ply of a pneumatic tire for a passenger car, the cord has a twist ratio of polyethylene naphthalate (PEN): polyvinyl alcohol (PVA) at a ratio of 1: 1 to 2 to 1 to 2: 1 and 200 to 600 TPM (Twist Per). Cap ply code for pneumatic tires for passenger cars, characterized in that the composite fiber (meter). The cord ply cord for passenger pneumatic tires according to claim 1, wherein the cord arrangement density (EPI) of the tire cap ply is 10 to 40 per inch. [Claim 3] The cord of claim 1 or 2, wherein polyethylene naphthalate (PEN) and polyvinyl alcohol (PVA) are 100 to 2000 denia.

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