JP2001140142A - Cord fabric and ply material for tire cord using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cord fabric capable of preventing cord from being disordered in arrangement when vulcanized and molded, improving uniformity of a tire, and achieving decrease in weight of the tire. SOLUTION: This cord fabric is woven from a warp 4 obtained by using a tire cord and a weft 5, wherein the weft 5 is made of a radiation- disintegration type polymer which is disintegrated by irradiation of radioactive rays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be suitably used as a ply material such as a carcass ply or a belt ply of a pneumatic tire, suppresses a disorder of a cord arrangement, and contributes to improvement of tire uniformity and weight reduction. The present invention relates to a woven fabric and a ply material for a tire using the same.

[0002]

2. Description of the Related Art FIG.
As shown in (A), the front and back of a woven fabric C woven with a warp A using a tire cord and a thin weft B entangled with the warp A at a relatively coarse interval were covered with a topping rubber G. A cloth D with rubber is generally used. The weft yarn B is mainly used to prevent the warp yarn A from being loosened when the warp yarn A is subjected to an adhesive application treatment (so-called dip treatment).

[0003]

However, when a tire is produced using such a cloth D with rubber,
At the time of vulcanization molding, as shown in FIG. 5 (B), warp yarns A are not arranged on one plane but in a staggered arrangement due to the extension of weft yarns B. As a result, in order to minimize the coating thickness t of the tire cord with the topping rubber G, an extra rubber thickness is required for the step d due to the staggered arrangement of the warp yarns A, which leads to an increase in cost and weight. There is a problem of inviting. Weft B
This prevents uniform inflation and cord arrangement at the time of vulcanization molding, and causes a reduction in tire uniformity.

In order to avoid the above-mentioned adverse effects caused by the weft yarn B, for example, Japanese Patent Application Laid-Open No.
It has been proposed to cut a weft thread by applying an unreasonable tension to a weft thread B of a cloth D with rubber by using a weft thread cutting device E as schematically shown in FIG. However, in the cutting by such an apparatus, the cut length and frequency of the weft yarn B may become uneven, and it is difficult to sufficiently improve the uniformity of the tire by making the warp (tire cord) interval uneven. .

Accordingly, the present invention is based on the fact that the weft is formed using a radiation-degradable polymer, and the tensile strength at break of the weft itself can be remarkably reduced by radiation irradiation. Aiming to provide a cord fabric and a ply material for tires using the same, which have almost no binding force, suppress the disorder of cord arrangement at the time of vulcanization molding, and can achieve improvement of tire uniformity and weight reduction, etc. And

[0006]

In order to achieve the above object, a first invention of the present application is a cord fabric, which is woven by a warp using a tire cord and a weft, and wherein the weft is a radiation weave. Characterized by being composed of a radiation decay type polymer that is decayed by irradiation.

The radiation-degradable polymers include polyisobutylene, poly-α-methylstyrene, polymethacrylamide, polymethacrylonitrile, polyvinylidene chloride, polychlorinated ethylene trifluoride, polyfluoroethylene monochloride, It can be selected from the group consisting of methacrylic acid and its esters, epichlorohydrin rubber, and isobutylene-isoprene copolymer rubber.

A second invention of the present application is a ply material for a tire, characterized in that the ply material is made of a rubber-attached cloth in which at least one surface of the cord fabric is covered with topping rubber.

[0009] The rubber-attached cloth can break the weft yarn by radiation irradiation treatment. The radiation irradiation treatment is preferably an electron beam irradiation treatment for absorbing an electron beam of 1 to 5 Mrad.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a cord fabric of the first invention of the present application will be described with reference to an embodiment of the present invention together with an embodiment of a ply material for a tire of the second invention. In FIG.
The ply material 1 for a tire is formed from a cloth 3 with a rubber coated with a topping rubber G on at least one surface of a cord fabric 2, in this example, both surfaces.

The cord fabric 2 is woven by warp yarns 4 using tire cords and weft yarns 5. In the present invention, the weft yarns 5 are particularly formed by using a radiation-degradable polymer. Has features.

Here, as the warp 4, various conventional tire cords such as a metal fiber cord such as a steel cord or an organic fiber cord such as nylon, polyester, rayon and aromatic polyamide can be suitably used. The material, twist structure, thickness, etc. are required for tire performance,
It can be set freely according to the site to be used, the purpose, and the like.

As the weft yarn 5, a so-called multifilament cord in which a plurality of filaments made of a radiation-degradable polymer are twisted with each other, or a monofilament cord composed of one filament is used.

As is well known, the radiation-degradable polymer is a polymer material having a property that bonds between molecules in the main chain are destroyed by irradiation with radiation, for example, polyisobutylene, poly-α-methylstyrene, Examples thereof include polymethacrylamide, polymethacrylonitrile, polyvinylidene chloride, polychlorinated ethylene trifluoride, polymonochlorofluoroethylene, polymethacrylic acid and its esters, epichlorohydrin rubber, and isobutylene-isoprene copolymer rubber. Any polymer selected from these groups can be suitably used as the material of the weft yarn 5 of the present invention. In addition, it is also possible to form the filaments by using different kinds of polymers selected from the above-mentioned groups, respectively, and form the weft yarn 5 as a composite cord obtained by twisting them into one.

The cord fabric 2 is made of a well-known conventional cord weaving machine using a warp array 4A in which a plurality of the warp yarns 4 are aligned in parallel with each other, and the weft yarns oriented in a direction substantially perpendicular to the warp yarns 4. 5 can be formed.

Then, the topping rubber G is added to the cord fabric 2.
After applying an adhesive application treatment (so-called dip treatment) for strengthening the adhesive force with the rubber and drying it, at least one surface, in this example, both surfaces in this example, is covered with the topping rubber G to form the rubber-attached cloth 3. The ply material 1 can be formed. The topping rubber G can be coated by using a well-known conventional topping device 21 having, for example, four roll-type calendars 20, as illustrated in FIG.

Here, as the topping rubber G, it is preferable to use a radiation cross-linkable rubber which does not collapse by the radiation irradiation. Examples of the radiation crosslinked rubber include isoprene rubber (IR), natural rubber (NR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), nitrile rubber (NBR), ethylene propylene rubber (EPDM), Examples include chloroprene rubber (CR), acrylic rubber, silicon rubber (Q), fluorine-based rubber, chlorinated polyethylene (CPE), and the like.
Among them, a rubber in which one or two or more kinds selected from IR, NR, BR, and SBR are mixed is preferable from the viewpoint of tire performance, adhesiveness with a tire constituent member, and the like.
Table 1 shows an example of a preferable rubber composition for the topping rubber G.

[0018]

[Table 1]

In the present embodiment, the ply material 1 covered with the topping rubber G is once wound on a roll 22 and then transferred to a radiation irradiation apparatus 23 as schematically shown in FIG. The irradiated ply material 1A in which the weft yarn 5 is broken down by the radiation irradiation treatment is processed. The irradiated ply material 1A is wound around the roll body 24 as a top anti-aperture 24A for forming a tire ply, and is stored or transferred to the next step.

In the figure, 30 is a device for rewinding the ply material 1 from the roll 22, 31 is a device for winding the irradiated ply material 1 A onto the roll 24, and 32 is a radiation irradiation device 23. Material 1 in the barrier 23A
A transport device 33 for transporting at a predetermined processing speed is an accumulator for adjusting the processing speed and the winding speed or the rewinding speed.

In the radiation irradiation apparatus 23, the ply material 1 passing through the barrier 23A is irradiated with the radiation
Irradiation is performed from 3B.

Examples of the radiation include X-rays, γ-rays, electron beams, proton beams, deuteron beams, α-rays, β-rays and the like. It is preferable because it is easy. The irradiation amount or absorbed dose of electron beam irradiation needs to be at a level at which the weft yarn 5 can be broken down to some extent by electron beam irradiation to reduce its tensile strength, and preferably the absorbed dose is 1.0 M
rad or more. Irradiation beyond 5.0 Mrad is not preferable because it is economically inefficient and may reduce the strength of the warp yarn 4. Therefore, the upper limit of the absorbed dose is preferably 5.0 Mrad or less, more preferably 3.0 Mrad or less. The acceleration voltage at this time is usually about 300 to 700 kV.

In this manner, the ply material 1 is subjected to the radiation irradiation treatment without damaging the topping rubber G and the warp yarns 4 and without impairing the uniformity of the arrangement of the warp yarns 4. The strength is significantly reduced, and the binding force on the warp yarn 4 can be almost eliminated. Therefore, when a tire is formed using this irradiated ply material 1A, the staggered arrangement of the tire cords in the vulcanization molding is suppressed, and the topping rubber G can be formed with a minimum thickness. Weight and cost reductions can be achieved.
In addition, it does not hinder inflation in the mold and can ensure a high uniformity of the tire.

Further, in the present embodiment, the radiation irradiation treatment causes the topping rubber G to crosslink to some extent and the modulus to be increased appropriately. Accordingly, even when the binding force to the warp yarns 4 has been lost, the warp arrangement is prevented from being disturbed during the subsequent handling such as transfer, and the quality accuracy can be maintained high.

As shown in FIG. 4, the ply material 1A is cut into sheet pieces 25 at an inclination angle α with respect to the warp yarns 4 and the edges e, e of the sheet pieces 25 are successively connected to form a tire. Code (warp 4) to tire equator CO
After forming the tire plies 26 arranged at the inclination angle α, the tire plies 26 are put into a tire forming apparatus in order to manufacture a green tire. Therefore, the timing of performing the irradiation treatment
Any method may be used as long as it is between the time when the topping rubber G is adhered to the cord fabric and the ply material 1 is formed and the time when the material is put into the tire forming apparatus.

[0026]

EXAMPLE A ply material obtained by covering the front and back of a woven fabric with a topping rubber was prototyped based on the specifications shown in Table 2, and the weft tension in the irradiated ply material obtained by subjecting the sample ply material to radiation irradiation. The breaking strength was measured.

A pneumatic tire using the irradiated ply material as a carcass was formed. Then, the tire was disassembled after vulcanization, and the step difference d (shown in the figure) when the warps were staggered in the carcass was measured.

[0028]

[Table 2]

As shown in Table 2, the ply materials of the examples are:
Radiation irradiation treatment can significantly reduce the tensile breaking strength of the weft. As a result, it was confirmed that the restraining force on the warp was almost eliminated, and staggered arrangement in the warp could be effectively prevented.

[0030]

As described above, in the present invention, since the weft yarn is formed using a radiation-degradable polymer, the tensile breaking strength of the weft yarn itself is significantly reduced by radiation irradiation, and the binding force on the warp yarn is lost. It becomes possible. As a result, it is possible to suppress the disorder of the cord arrangement at the time of vulcanization molding, and to improve the uniformity and weight of the tire.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a ply material of the present invention together with a cord fabric.

FIG. 2 is a diagram schematically illustrating an example of a topping device.

FIG. 3 is a diagram schematically illustrating an example of a radiation irradiation processing apparatus.

FIG. 4 is a diagram illustrating formation of a tire ply from the top side.

FIG. 5A is a front view illustrating a conventional ply material,
(B) is a cross-sectional view explaining the problem.

FIG. 6 is a sectional view showing a conventional technique.

[Explanation of symbols]

 1, 1A tire ply material 2 cord fabric 3 rubber cloth 4 warp 5 weft G topping rubber

Claims (5)

[Claims] 1. A cord fabric woven by a warp yarn and a weft yarn using a tire cord, wherein the weft yarn is made of a radiation-disintegrable polymer that disintegrates upon irradiation with radiation. 2. The radiation-degradable polymer includes polyisobutylene, poly-α-methylstyrene, polymethacrylamide, polymethacrylonitrile, polyvinylidene chloride, polychlorinated ethylene trifluoride, polyfluoroethylene monochloride, polymethacrylic acid. The cord fabric according to claim 1, wherein at least one selected from the group consisting of acids and esters thereof, epichlorohydrin rubber, and isobutylene-isoprene copolymer rubber. 3. A ply material for a tire, comprising a rubber-coated cloth wherein at least one surface of the cord fabric of claim 1 or 2 is covered with topping rubber. 4. The ply material for a tire according to claim 3, wherein the cloth with rubber has the weft broken by radiation irradiation treatment. 5. The ply material for a tire according to claim 4, wherein the radiation irradiation treatment is an electron beam irradiation treatment for absorbing an electron beam of 1 to 5 Mrad.