KR100787761B1 - Complicated steel code and radial tire using the same - Google Patents

Abstract

A composite steel cord is provided to improve rubber penetration and to improve durability of a tire by reducing fretting. A composite steel cord is constructed with a first core(1) having a fabric filament, a second core(2) having three steel filaments(2a), and a third core(3) having eight or seven filaments(3a). The second core and the third core wrap around the first core and are twisted in the same direction with the same frequency. The diameter of the filaments of the second and third cores is 1~5 times the diameter of the filament of the first core.

Description

Complex steel code and radial tire using the same}

1 is a steel cord for tire reinforcement of a conventional two-layer structure.

2 is a cross-sectional view showing a composite steel cord including one fiber filament according to an embodiment of the present invention.

3 is a cross-sectional view showing a steel cord wrapped on the steel cord of FIG. 2 as another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1: 1st layer core 2: 2nd layer core

3: 3rd layer core 4: lapping core

1a: fiber filament, 2a: steel filament constituting the second layer core

3a: steel filament constituting the third layer core

4a: steel filament constituting the wrapping core

1b: steel filament constituting the one-layer core in the prior art

2b: steel filament constituting the one-layer core in the prior art

The present invention relates to a composite steel cord for reinforcing tires and a radial tire using the same. More specifically, the twist direction and the twisting period of the first layer core composed of one fiber filament and the second and third layer cores surrounding the same The present invention relates to a composite steel cord for reinforcing tires and a radial tire using the same.

Typically, steel is used for reinforcing rubber products in carcass, bead and belt parts of heavy duty radial tires for truck buses. In particular, steel cords used for the carcass and belt parts are generally brass-plated and drawn on carbon steel with a carbon content of 0.7 to 1.00% by weight to produce filaments of a desired diameter. 2 + 5, 2 + 7, 3 + 6, 3 + 8, 3 + 9, 3 + 9 + 15 and the like).

Currently, 3 + 9 + 15 + w (wrapping) structure is commonly used for truck bus tires. To explain the manufacturing method of the tire, first, three steel filaments are twisted in one of the left and right directions to form the first layer. A core is formed, and nine steel filaments are twisted in the same direction as the first layer core, and have a different twisting cycle with the first layer core to form a second layer core to wrap and integrate the first layer core. Subsequently, the 15 layered steel filaments are twisted in a direction opposite to the first layer core and the second layer core, and have a different twisting cycle with the second layer core to form a third layer core so that the third layer core wraps and integrates the second layer core. Be sure to Then, the lapping core is formed at a predetermined twisting period by twisting one steel filament in a direction opposite to the third layer core, and the lapping core is integrated to surround the third layer core to complete the wrapped three-layer steel cord.

The wrapped three-layered steel cord is used as a steel cord for reinforcing the carcass or belt part of a large tire such as a truck or a bus because the three-layer steel cord has a high strength by a large number of filaments and a large binding force between the filaments due to the lapping treatment. have. However, the wrapped three-layer steel cord has different twisting directions and / or twisting cycles of the first, second, and third layer cores, so that mechanical friction between the filaments and moisture Fretting fatigue, which causes chemical corrosion at the same time due to salinity, is large, and the durability of the wrapped steel cord and the tire to which the tire is applied is greatly reduced, and the first, second, and third layers are also reduced. Since the core and the wrapping core have to be twisted separately in a separate process, there is a problem that productivity is lowered and product cost is increased.

In order to solve the above problems, Korean Patent No. 305503 discloses a steel cord for tire reinforcement having a 3/7 or 3/8 structure in which the twist directions of the filaments constituting the core layer are the same. Figure 1 schematically shows a cross section of a steel cord of this structure.

Referring to FIG. 1, the 3/7 or 3/8 structure includes a first layer core 1 composed of three filaments 1b and seven or eight filaments 2b to form a first layer core. It is made of a wrapping second layer core (2), the twisting direction of the first layer core and the second layer core is the steel cord for tire reinforcement of the two-layer structure.

However, since the twisting cycles of the first layer core 1 and the second layer core 2 are the same, the manufacturing process of the steel cord is simplified, but the contact area due to the same twisting length and the twisting cycle is maximized to three filaments. Since the rubber penetration is not completely made up to the inner layer of the first layer, if the tire is repeatedly bent by an external force while driving the vehicle, there is a possibility that the fretting fatigue occurs, and the durability of the tire is applied. do.

One object of the present invention for solving the above-mentioned problems of the prior art is a first layer core composed of one fiber filament and twisting to wrap it so as to improve rubber permeability and at the same time reduce frets and improve tire durability. A composite steel cord and a radial tire using the same include a second layer and a third layer core having the same direction and twist period.

One aspect of the present invention for achieving the above object is

A first layer core composed of one fiber filament,

A second layer core consisting of three steel filaments, and

A steel cord including a third layer core composed of seven or eight steel filaments, wherein the second layer core surrounds the first layer core and the third layer core surrounds the second layer core. And a twist direction and a twist cycle of the second layer core and the third layer core are the same.

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

The composite steel cord for tire reinforcement of the present invention is a steel comprising a first layer core composed of one fiber filament, a second layer core composed of three steel filaments, and a third layer core composed of seven or eight steel filaments. The cord includes a structure in which the second layer core surrounds the first layer core, the second layer core surrounds the third layer core, and a twisting direction and twist between the second layer core and the third layer core. The cycle is characterized by the same. The composite steel cord includes a wrapping core composed of one steel filament surrounding the third layer core, and the twisting direction of the wrapping core may be opposite to the twisting directions of the second layer core and the third layer core.

FIG. 2 shows an example of a steel cord according to the present invention. Referring to this, the steel cord according to the present invention includes a first layer (1) core composed of one fiber filament (1a) and three steel filaments (2a). A second layer core (2) consisting of a third layer core (3) consisting of eight (or seven) filaments (3a), and a second layer core (2) and a third layer core ( 3) is integrated while surrounding the 1st layer core 1, and the twisting direction and twisting cycle of the 2nd layer core 2 and the 3rd layer core 3 become the same.

Fiber filaments constituting the first layer core include nylon-6 dipped in a resorcinol (M-dihydroxybenzene) -formaldehyde layer. It is preferably nylon-66, polyester, rayon, aramid, glass fiber or carbon fiber. By dipping a resorcinol formaldehyde layer or the like on the fiber filament, adhesion with rubber becomes possible.

The filament constituting the first layer core 1 of the present invention is composed of one filament 1a of fiber, the diameter d1 of which is 0.10 to 0.40 mm, and the second layer core 2 and the third layer core. The diameters d2 and d3 of the filaments 2a and 3a constituting (3) are preferably in the range of 0.8 to 5 times the diameter d1 of the first layer core filament 1a.

 The twisting period of the second layer core 2 and the third layer core 3 having the same twisting direction and twisting cycle is 20 to 100 times the filament diameter d3 constituting the third layer core 3. .

Resorcinol formaldehyde layer dipped nylon-6 that meets these conditions. The first layer core consisting of one filament of nylon-66, polyester, rayon, aramid, glass fiber, carbon fiber, etc. is a space where rubber can penetrate inside the second layer core when topping rubber into steel cord It provides the effect of improving the rubber adhesion and reducing the fretting wear compared to the case where the first layer core is made of steel, thereby improving the durability of the tire.

3 is a diagram illustrating another example according to the present invention, which is a schematic cross-sectional view of a steel cord wrapped with the steel cord of FIG. 2, wherein the resorcinol formaldehyde layer constituting the first layer core 1 is dipped. The diameters of the steel filaments 2a and 3a constituting the fiber filament 1a, the second layer core 2, and the third layer core 3 and their relations are shown in FIG. The twisting direction of the steel filament 4a of the wrapping core 4 is opposite to that of the second and third layers, and the twisting period is 2 to 10 mm.

On the other hand, the steel cord according to the present invention can be used as a reinforcing steel cord of one or more of the carcass portion, belt portion and sieving portion of the pneumatic radial tire.

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  One

Example 1 is a steel cord having a 1 + 3/8 structure according to the present invention, in which a resorcinol formaldehyde layer dipped polyester fiber is used for a first layer core filament and a carbon content is used as a second and third layer core. Using 0.82wt% filament, the first layer core was 0.15mm in diameter and the first strand, the second and third layer cores were 0.35mm, respectively. The twist length of the three-layer core was the same as 18.0 mm to prepare a steel cord.

Example  2

Example 2 is also a steel cord having a 1 + 3/8 structure according to the present invention, and is carried out in the same manner as in Example 1, except that resorcinol formaldehyde layer dipped nylon-66 fibers are used for the first layer core filament. To produce a steel cord.

Comparative example  One

Comparative Example was prepared in the same manner as in Example 1 except that the first layer core filament was not used as shown in FIG.

Steel cords prepared in Examples 1 and 2 and Comparative Example 1 were tested by the following physical property evaluation method, and the results are shown in Table 1 below.

Property evaluation method

* Fatigue limit stress was measured by RBT (Rotating Beam Tester, made in Bekaert) (rotation of 1 million times or more at fatigue limit stress).

* Initial rubber adhesion was measured by ASTM D2229-99 of Instron at 150 ° C x 30min vulcanization conditions.

* The heat aging property was determined by an oven ratio of 100 ° C., the moisture resistance was determined by the ratio of adhesive strength after aging at 70 ° C. and 96% RH, respectively, and the adhesion was measured by ASTM D2229-99 of Instron.

* The hot water resistance was determined at 70 ° C., and the salt water resistance was determined by the ratio of adhesion after aging at 20% NaCl. The adhesion was measured by Instron's ASTM D2229-99.

As can be seen from Table 1, the 1 + 3/8 structure comprising the resorcinol formaldehyde layer dipped fiber one-layer core of Examples 1 and 2 according to the present invention is compared throughout durability including initial adhesion It can be seen that the effect is superior to the 3/8 structure of Example 1.

Composite steel cord according to the present invention can improve the rubber permeability and at the same time reduce the fritting to improve the tire durability can be used to produce excellent radial tires.

Claims (7)

A first layer core composed of one fiber filament, A second layer core consisting of three steel filaments, and A steel cord including a third layer core composed of seven or eight steel filaments, wherein the second layer core surrounds the first layer core and the third layer core surrounds the second layer core. The twist direction and twist period of the second layer core and the third layer core are the same, and The diameter of the steel filament constituting the second layer and the third layer core is 1 to 5 times the diameter of the first layer core, composite steel cord for tire reinforcement. 2. The composite steel cord of claim 1, wherein the composite steel cord comprises a wrapping core composed of one steel filament surrounding the third layer core, wherein the twisting direction of the wrapping core is twist of the second layer core and the third layer core. Composite steel cord for tire reinforcement, characterized in that the opposite direction. The nylon-6 according to claim 1, wherein the fiber filaments constituting the first layer core are dipped in a resocinol formaldehyde layer. Nylon-66, polyester, rayon, aramid, glass fiber or carbon fiber composite steel cord characterized in that the carbon fiber The composite steel cord for tire reinforcement according to claim 1, wherein the diameter of the resorcinol formaldehyde layer dipped fiber filaments constituting the first layer core is 0.10 to 0.40 mm. The composite steel cord for tire reinforcement according to claim 4, wherein a twisting period of the second layer and the third layer core is 20 to 100 times the diameter of the filaments constituting the third layer core. The composite steel cord for tire reinforcement according to claim 2, wherein a twisting period of the wrapping core is 2 to 10 mm. The pneumatic radial tire according to any one of claims 1 to 6, wherein the steel cord is applied to the reinforcing steel cord of at least one of a carcass portion, a belt portion, and a piercing portion.

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