JP2002338749A - Composite of steel cord with rubber composition and tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel cord/rubber composite which has improved the initial adhesion and deterioration-resistant adhesive properties between a steel cord and a rubber composition and the economy of the production cost. SOLUTION: The composite 10 of a steel cord with a rubber composition is composed of a steel cord consisting of a coating layer and a steel cord 1 and a rubber composition, and the coating layer is constituted of an inner coating layer 2 which is composed of a composition comprising a rubber component, a cobalt compound, and sulfur and directly covers the above steel cord and an outer coating layer 3 which is composed of a rubber composition having contents of the cobalt compound and sulfur smaller than those in the inner coating layer and envelopes the outside of the above inner coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for coating a steel cord and a composite of a steel cord and a rubber composition using the same. The present invention relates to a rubber composition for steel cord coating with improved economic efficiency, and a composite of a steel cord and a rubber composition comprising the rubber composition and a steel cord.

[0002]

2. Description of the Related Art In general, steel cords are used as reinforcing materials in rubber products such as automobile tires and conveyor belts in order to improve their performance.
In particular, the demand for safety, high-speed running and durability of automobile tires is increasing more and more, but the adhesive layer between the steel cord and rubber used as tire reinforcing material is generated by the heat generated during tire running. If destroyed, it can cause serious tire failure. Therefore, it is desired to further improve the adhesiveness between the steel cord and the rubber.

[0003] Conventionally, this steel cord is usually plated with brass, which is an alloy of copper and zinc, in order to increase the adhesive strength with rubber and enhance its reinforcing effect, and react with sulfur in the rubber composition. The direct bonding method is generally used. However, in a composite of a steel cord and a rubber composition, the incorporation of a large amount of sulfur in the rubber significantly deteriorates the heat aging characteristics of the rubber composition after vulcanization. For this reason, a method of reducing the compounding amount of the sulfur component, using a bismaleimide compound as a crosslinking agent in place of the compound, and improving the heat aging characteristics of the rubber composition has been proposed.
Reducing the sulfur in the rubber composition or blending a bismaleimide compound would significantly reduce the initial adhesion with conventional brass-plated steel cords, making it difficult to apply to tires There was a problem.

[0004] On the other hand, the coating rubber composition in contact with the steel cord has a
As the adhesion promoter, a cobalt salt of an organic acid is usually blended. However, when a large amount of the organic acid cobalt salt is used, the adhesiveness immediately after vulcanization, that is, the initial adhesiveness, is excellent, but the organic acid cobalt salt and the vulcanization accelerator in the rubber composition and aging prevention Reacting with the agent, etc., to promote thermal deterioration of the rubber and the generation of water thereby, there is a disadvantage that the deterioration resistance is inferior, further, the molecular chain of the rubber is cut in an unvulcanized state, There is a disadvantage that the performance of rubber as a tire material is reduced, and the cobalt salt of an organic acid is very expensive, so that there is a problem in terms of economic efficiency.

[0005] When a metal salt of another organic acid is blended in place of the cobalt salt of an organic acid, the adhesive strength immediately after vulcanization is inferior, and the metal salt of an organic acid instead of cobalt has come to practical use. It is not the fact.

[0006] Accordingly, a composite of a steel cord and a rubber composition, which is excellent in initial adhesiveness and obtains stable deterioration-resistant adhesiveness even when the amount of sulfur is reduced, and further, the addition of a cobalt salt of an organic acid. There is a need for a composite of a steel cord and a rubber composition that is excellent in initial adhesion even when the amount is reduced, and that provides stable degradation-resistant adhesion.

[0007] Under such demands, various techniques have been disclosed for improving the adhesion between the steel cord and the rubber.

For example, a technique is disclosed in which a rubber component contains a cobalt salt of an organic acid and sulfur, and a cobalt plating layer is provided on the surface of a steel cord (Japanese Patent Laid-Open No. 64-31).
No. 837), and a further improved technology, in which a rubber component contains a cobalt salt of an organic acid, sulfur and a bismaleimide compound, and a cobalt plating layer is provided on the surface of a steel cord (Japanese Patent Laid-Open No. Hei 4- 11637
Publication), acetylacetone cobalt,
A technique in which sulfur is contained and a brass plating layer is provided on the surface of the steel cord so that the ratio of copper / zinc is 60/40 to 65/35 (JP-A-5-65370), a rubber component before vulcanization Water content in the range of 0.2 to 0.
7% and a technique of providing a cobalt plating layer on the surface of the steel cord (Japanese Patent Laid-Open No. 5-24)
No. 7271), a technique of adhering an organic solvent containing a diene rubber component and a cobalt compound to a galvanized steel cord and vulcanizing and bonding with a rubber composition containing no cobalt compound (Japanese Patent Application Laid-Open No. Hei 10-324753). Technology for adhering a reaction mixture mainly composed of a cobalt salt of an organic carboxylic acid and boron metal soap to a steel cord (Patent 2
823857), a technique in which rosin or a rosin derivative, sulfur, a cobalt salt of an organic acid, or an organic chlorine compound is contained in a rubber component, and a galvanized layer is provided on the surface of a steel cord (Japanese Patent Laid-Open No. 11-21389). ), The rubber component has a nitrogen adsorption specific surface area (BET) of 1
A technique for containing silica powder of 50 m ² / g or less (JP-A-2000-7839), a technique for containing a porous inorganic filler in a rubber component (JP-A-2000-7838), and the like are disclosed. .

[0009] However, according to the above-mentioned technology, the initial adhesion and the deterioration-resistant adhesion between the rubber and the steel cord are sufficiently ensured, and an economical tire using the composite of the steel cord and the rubber composition is obtained. It was difficult to provide.

[0010]

SUMMARY OF THE INVENTION The present invention provides a rubber composition for a steel cord coating which has improved initial adhesion and deterioration-resistant adhesion to a steel cord under such circumstances, and a steel using the same. It is an object of the present invention to provide a composite of a cord and a rubber composition.

[0011]

The bonding reaction between the steel cord and the rubber composition is performed at a thickness of about several tens to several hundreds of mm at the bonding interface, and the bonding characteristics here are important. From this, the present inventors have found that when bonding a steel cord and a rubber composition, it is sufficient that the rubber composition having excellent adhesion performance with the steel cord only exists as a thin film at the bonding interface between the two. Focused attention, as a result of intensive studies to solve the above problems, the rubber composition by using a composite of steel cord and rubber composition consisting of an inner coating layer and an outer coating layer and a steel cord each having a different composition, The present invention has found that it is possible to provide an economical tire using a composite of a steel cord and a rubber composition, while ensuring good initial adhesion and deterioration-resistant adhesion to a steel cord. Was completed.

That is, the invention according to claim 1 is a composite of a steel cord and a rubber composition comprising a coating layer and a steel cord, wherein the coating layer comprises a rubber component, a cobalt compound, sulfur, An inner coating layer comprising a rubber composition comprising: a rubber composition having a content of cobalt compound and sulfur smaller than that in the inner coating layer; And a rubber composition comprising a steel cord and an outer coating layer enclosing the rubber composition.

According to a second aspect of the present invention, in the composite of the steel cord and the rubber composition according to the first aspect, the rubber composition constituting the inner coating layer comprises a cobalt compound based on 100 parts by weight of the rubber component. 0.5 to 5 parts by weight of sulfur and 3 to 8 parts by weight of sulfur.

According to a third aspect of the present invention, in the composite of the steel cord and the rubber composition according to the first or second aspect, the cobalt compound is a cobalt salt of an organic acid.

According to a fourth aspect of the present invention, in the composite of the steel cord and the rubber composition according to any one of the first to third aspects, the thickness of the inner coating layer of the rubber composition is 0.1 to 1%. 0.5 mm.

According to a fifth aspect of the present invention, there is provided a tire using the composite of the steel cord and the rubber composition according to any one of the first to fourth aspects.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The composite of the steel cord and the rubber composition according to the present invention,
It is characterized by comprising a steel cord and a coating layer of a rubber composition containing a rubber component, a cobalt compound, and sulfur.

As the rubber component in the rubber composition of the present invention, natural rubber (NR) or synthetic rubber is used. As the synthetic rubber, for example, polybutadiene rubber (BR), polyisoprene rubber (IR), styrene / butadiene rubber (SBR), butyl rubber (IIR), halogenated butyl rubber, chloroprene rubber (CR), and the like are preferable. Butyl rubber having a paramethylstyrene group (specifically, a copolymer of isobutylene and p-halogenated methylstyrene, etc.), acrylonitrile-
Butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM) and the like can also be mentioned as suitable ones.

The rubber component in the rubber composition of the present invention comprises:
Depending on the use of the rubber product using a steel cord as a reinforcing material, one or two or more types are appropriately selected from natural rubber and the above-mentioned synthetic rubber and used. From the viewpoint of characteristics and the like, a rubber component containing natural rubber and / or synthetic isoprene rubber in a proportion of 50% by weight or more is preferable.

In the present invention, as the cobalt compound, cobalt stearate, cobalt naphthenate, cobalt oleate, cobalt linoleate, cobalt neodecanoate, cobalt orthoborate, cobalt octylate, rosin cobalt, tall oil, which are familiar with rubber, are used. Cobalt acid or a cobalt salt of an organic acid such as a cobalt boron complex can be suitably used. This is because the cobalt salt of an organic acid has good affinity with oil and rubber, and can keep good adhesion between the steel cord and rubber.

In general, a cobalt salt of an organic acid is used as a liquid phase oxidation catalyst. A method of adding a cobalt acetate solution to an aqueous solution of an alkali soap of a corresponding organic acid to cause double decomposition precipitation, a method of preparing an organic acid and cobalt (II) oxide And a method of adding an aqueous solution of cobalt sulfate or cobalt nitrate to a benzine solution of an organic acid.

In the present invention, the content of the cobalt compound in the inner coating rubber composition is desirably 0.5 to 5 parts by weight per 100 parts by weight of the rubber component. If the content of the cobalt compound is less than 0.5 part by weight, the initial adhesion and the deterioration resistance adhesion between the steel cord and the rubber composition tend to decrease, while the content of the cobalt compound is 5 parts by weight. When the amount exceeds the above, no improvement in the initial adhesiveness is recognized for the amount, and the production cost increases with an increase in the content of the cobalt compound, and the cobalt salt of the organic acid and the rubber composition in the rubber composition This is because a rubber accelerator reacts with a vulcanization accelerator, an antioxidant, or the like, and promotes thermal deterioration of the rubber and generation of water therefrom, so that the deterioration resistance of the rubber composition tends to decrease.

In the present invention, the outer coating rubber composition comprises:
It is desirable that the content of the cobalt compound is less than the content of the cobalt compound in the inner coating rubber composition, or that the cobalt compound is not contained at all. When the content of the cobalt compound in the outer coating rubber composition exceeds the content of the cobalt compound in the inner coating rubber composition, the production cost increases due to the increase in the content of the cobalt compound, and the organic acid Reacts with the vulcanization accelerator and anti-aging agent in the rubber composition to promote the thermal deterioration of the rubber and the formation of water thereby reducing the deterioration resistance of the rubber composition. This is because there is a tendency. Also, since the outer coating rubber composition does not directly contact the steel cord,
Even if it does not contain a cobalt compound, there is no particular effect on the adhesion between the steel cord and the rubber composition.

In the present invention, in the inner coating rubber composition
The sulfur content is 3 to 8 per 100 parts by weight of the rubber component.
A range of parts by weight is preferred. Sulfur content less than 3 parts by weight
Then, Cu which is the source of the adhesive strength_XS (Steel cord
It is formed by the reaction between copper and sulfur during brass plating. )
Can not supply enough sulfur for the production of
It may be insufficient. On the other hand, the sulfur content is eightfold
If the amount exceeds _XHypertrophy due to excessive generation of S
Cu_XCohesive failure of S occurs, lowering adhesive strength
Along with this, the heat aging resistance as a rubber property tends to decrease
Can be seen.

In the present invention, the outer coating rubber composition comprises:
It is desirable that the content of sulfur is smaller than the content of sulfur in the inner coating rubber composition, and it is particularly desirable that the content be 3 parts by weight or less per 100 parts by weight of the rubber component. When the content of the cobalt compound in the outer coating rubber composition exceeds the content of the cobalt compound in the inner coating rubber composition,
This is because excessive generation of Cu _X S causes cohesive failure of the enlarged Cu _X S, which tends to reduce the heat aging resistance as rubber physical properties.

The rubber composition of the present invention may contain, if necessary, a compounding agent usually used in the rubber industry in a usual amount, in addition to the above components, within a range not to impair the object of the present invention. They can be appropriately blended. Specifically, softeners such as process oils, guanidines such as diphenylguanidine, thiazoles such as mercaptobenzothiazole,
Vulcanization accelerators such as sulfenamides such as N, N'-dicyclohexyl-2-benzothiazolylsulfenamide, thiurams such as tetramethylthiuram disulfide, and vulcanization accelerators such as zinc oxide (zinc white) , Amine-based,
Phenol-based or wax-based antioxidants,
It is also possible to add a compounding agent such as a filler such as carbon black, silica or calcium carbonate.

Of these, fillers such as carbon black and silica are used to increase the vulcanized rubber's tensile strength, breaking strength, tensile stress, hardness, etc., and to enhance abrasion resistance and tensile resistance. As a vulcanization accelerator, zinc oxide is known as a vulcanization accelerating aid which forms a complex compound with a fatty acid to enhance the vulcanization accelerating effect.

The carbon black used in the rubber composition of the present invention is preferably HAF, ISAF, SAF or the like. The content of carbon black is preferably in the range of 40 to 80 parts by weight per 100 parts by weight of the rubber component.

The content of other components used in the rubber composition of the present invention is as follows:
3 to 10 parts by weight of zinc oxide (zinc white), antioxidant 0.5
The range is preferably from 3 to 3 parts by weight, and from 0.5 to 2 parts by weight of the vulcanization accelerator.

The steel cord to which the rubber composition of the present invention is applied is plated with brass, zinc, or an alloy containing nickel or cobalt to improve the adhesion to rubber. It is particularly preferable that the substrate is plated with brass. When the Cu content in the brass plating of the steel cord is 75% by weight or less, preferably 40 to 70% by weight, good and stable adhesion can be obtained. The twist structure of the steel cord is not particularly limited.

The present invention provides a composite of a steel cord and a rubber composition comprising the above-mentioned rubber composition for steel cord coating and a steel cord, and the composite may be, for example, an automobile tire or a conveyor belt. It is suitably used as a reinforcing material for improving the performance of industrial rubber products.

The thickness of the inner coating rubber layer of the present invention is preferably in the range of 0.1 to 1.5 mm (average of two places, 0 to 180 °). When the thickness of the inner coating rubber layer is less than 0.1 mm, the inner coating rubber layer is difficult to be uniform, and sometimes the substrate may be exposed. 0.5mm
If it exceeds 300, it exceeds the thickness of the rubberized sheet, which is not preferable in terms of production efficiency and cost.

The thickness of the outer coating rubber layer of the present invention is not particularly limited. Depending on the intended use of the steel cord-rubber composition composite of the present invention, an outer covering rubber layer having various thicknesses can be topped.

In the present invention, the rubber composition of the outer coating layer, which is directly coated on the surface of the steel cord or steel wire, by coating the rubber composition of the inner coating layer on the surface of the steel cord or steel wire. The cobalt salt of the organic acid contained in the material can be removed or reduced to a very small amount. Rubber compounding of the outer coating layer that can suppress deterioration and increase in manufacturing cost has become possible.

In order to maintain stable heat-resistant adhesiveness, the rubber composition of the outer coating layer has a relatively large amount (3 to 8 parts by weight) of sulfur, which is conventionally contained in the rubber composition. It was possible to suppress the decrease in the heat aging resistance of the rubber material of the outer coating layer due to the excessive addition of sulfur, and the crack propagation resistance was greatly improved.

FIG. 1 illustrates a cross section of a typical embodiment of a composite of a steel cord and a rubber composition according to the present invention. Three steel wires 1 coated with the rubber composition 2 of the inner coating layer according to the present invention are twisted to form a composite of a steel cord and a rubber composition. Further, the rubber composition 3 of the outer coating layer according to the present invention is further topped on the outer side of the composite to constitute the composite 10 of the steel cord and the rubber composition according to the present invention. In addition,
In this embodiment, the number of twists of the steel wire 1 is not limited to three.

FIG. 2 illustrates a cross section of another embodiment of a composite of a steel cord and a rubber composition according to the present invention. A steel cord in which three steel wires 21 are twisted is coated with the rubber composition 22 of the inner coating layer according to the present invention, and forms a composite of the steel cord and the rubber composition. And the rubber composition 23 of the outer coating layer according to the present invention is further topped on the outside of the composite,
Composite 20 of steel cord and rubber composition according to the present invention
Is composed. In this embodiment, the number of twists of the steel wires 21 is not limited to three.

The method for producing a composite of a steel cord and a rubber composition according to the present invention comprises the steps of: adhering the rubber composition of the inner coating layer to the steel wire; and twisting the steel wire. And, further outside the inner coating layer, the content of the cobalt compound and sulfur is lower than the rubber composition of the inner coating layer, or the content of the cobalt compound is not contained, and the sulfur content is lower than that of the rubber composition of the inner coating layer. An outer coating layer adhering step of adhering a lower outer coating layer rubber composition.

In order to produce a composite of a steel cord and a rubber composition having the form shown in FIG. 1, first, in a step of attaching an inner coating layer, a rubber component, a cobalt compound, sulfur,
Is attached to a steel wire.
Thereafter, in a twisting step, the steel wire-rubber composite obtained through the above-mentioned attaching step is twisted to produce a composite of a steel cord and a rubber composition in the form shown in FIG. In this manufacturing method, the number of twists of the steel wire 1 is not limited to three.

In order to produce a composite of a steel cord and a rubber composition in the form shown in FIG. 2, first, in a twisting step, a steel cord is produced by twisting steel wires. Then, in the attaching step, a rubber composition containing a rubber component, a cobalt compound, and sulfur is attached to the steel cord, thereby producing a composite of the steel cord and the rubber composition in the form shown in FIG. In addition, also in this manufacturing method, the number of twists of the steel wire 21 is not limited to three.

In the inner coating layer adhering step, a rubber composition containing a rubber component, a cobalt compound and sulfur may be simultaneously extruded and adhered to a steel wire or a steel cord. A method in which the composition dissolved in an organic solvent is applied to a steel wire or a steel cord, sprayed, and a method of removing the organic solvent by spraying with hot air after being immersed is also excellent in terms of uniformity of the adhesion amount and simplicity. I have.

In the twisting step, the twist structure of the steel cord and the number of steel wires to be twisted are not particularly limited. The wire diameter and the cord diameter of the steel cord are appropriately selected according to their use when the composite is bonded to the rubber composition of the present invention.

FIG. 3 is a diagram illustrating an example of a method for producing a composite of a steel cord and a rubber composition having the form shown in FIG. 1 according to the present invention. Three unwinding rolls 4A, 4B, and 4C are provided in total, and a steel wire is prepared for each unwinding roll. Unwinding roll 4
In a passing line from A, 4B, 4C to the drum 5, each steel wire is coated with a rubber composition containing a rubber component, a cobalt compound, and sulfur dissolved in an organic solvent. . In drum 5,
The three steel wire-rubber composites are twisted,
A composite of steel cord and rubber composition is produced. Then, the composite of the steel cord and the rubber composition is applied to the drum 6
After passing through A and 6B, the drum passes through drums 7A, 7B, 7C and 7D and drums 8A and 8B, and is wound by a winding drum 9.

On the outside of the composite of the steel cord and the rubber composition of the inner coating layer manufactured through the series of steps of FIG.
The content of the cobalt compound and sulfur is lower than the rubber composition of the inner coating layer, or does not include the cobalt compound,
The content of sulfur is lower than that of the rubber composition of the inner coating layer, the rubber composition of the outer coating layer is topped, and then vulcanized under known conditions to obtain a composite of the steel cord and the rubber composition of the present invention. The body is manufactured.

The tire according to the present invention uses the composite of the steel cord and the rubber composition according to the present invention as a reinforcing material. The composite of a steel cord and a rubber composition according to the present invention can be used in any part using a reinforcing material, and can be suitably used for, for example, a carcass, a breaker, a band, and the like.

As a specific example, in a radial tire for an automobile, a toroidal carcass comprising a composite of a steel cord and a rubber composition according to the present invention, which is arranged substantially parallel to the meridional section of the tire, is used. , Arranged outside the carcass crown and inside the tread,
The use of the belt made of the composite of the steel cord and the rubber composition according to the present invention can greatly improve the durability life of the automotive radial tire.

The composite of a steel cord and a rubber composition according to the present invention can be suitably used as a reinforcing material for industrial rubber products such as a conveyor belt. For example,
When the steel cord-rubber composite according to the present invention is used as a reinforcing material for a steel cord conveyor belt often used in a high-temperature and high-humidity environment, extremely long-term reliability can be obtained, and inspection, repair, etc. Maintenance costs and labor can be reduced. In addition, it can be used as a reinforcing material for hoses, crawler belts, marine hoses and the like.

[0048]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

EXAMPLE 1 A steel wire drawn to a diameter of 0.27 mm was coated with copper 6
A brass plating of 3% by mass and 37% by mass of zinc was applied, and a mineral oil was sprayed. After that, three steel wires were twisted to have a cord diameter of 0.58 mm to produce a steel cord.

Subsequently, the steel cord was immersed in a toluene solution containing 10% by mass of the rubber composition of Formulation A shown in Table 1 and dried, and the thickness of the coated rubber layer was 0.1 to 1.5.
A composite (composite (I)) of a steel cord having a thickness of 0.5 mm (average thickness: 0.5 mm) and a rubber composition constituting the inner coating layer was prepared.

[0051]

[Table 1]

Subsequently, in the form shown in FIG.
The composite (I) 12 was topped with the outer coating rubber composition 33, 33a of Formulation B shown in Table 1 and vulcanized at 165 ° C. for 18 minutes to prepare a wet heat bonding sample (I).

Further, the complex (I) was mixed with the compound B shown in Table 1
And a top layer was formed with a rubber layer having a thickness of 1.15 mm to form a belt layer. Using the belt layer, a tire (I) was prototyped under the conditions shown in Table 2.

[0054]

[Table 2]

The end means the number of embedded steel cord / rubber composition composites per 5 cm of ply.

[0056] Comparative Example 1 Comparative Example 1, and the steel cord, a rubber composition constituting the inner coating layer, the complex of (complex (II)), were prepared under the same conditions as all complexes (I) .

Further, the composite (II) was topped with the outer coating rubber composition of Formulation A shown in Table 1, vulcanized at 165 ° C. for 18 minutes, and wet-heat bonded in the same manner as in Example 1. A sample for use (II) was prepared.

Further, the composite (II) was topped with the outer coating rubber composition of Formulation A shown in Table 1 so as to have a gauge of 1.15 mm to form a belt layer. Using the belt layer, a tire (II) was prototyped under the conditions shown in Table 2.

[0059] Comparative Example 2 Comparative Example 2, the steel cord, a rubber composition constituting the inner coating layer, the complex (complex (III)), the rubber compounding B of the inner coating layer shown in Table 1 Except for being composed of the composition, all were prepared under the same conditions as the composite (I).

Further, the composite (III) was topped with the outer coating rubber composition of Formulation B shown in Table 1 and 165 ° C.
Under the conditions of vulcanization for 18 minutes, in the same manner as in Example 1,
A sample (III) for wet heat bonding was prepared.

Further, the composite (III) was topped with the outer coating rubber composition of Formulation B shown in Table 1 so as to have a gauge of 1.15 mm to form a belt layer. Then, using the belt layer under the conditions shown in Table 2, the tire (III)
Was prototyped.

[0062] Example 2 Example 2, and steel cord, and a rubber composition constituting the inner coating layer, the complex (complex (IV)), the point thickness of the inner coating layer is 0.05mm Except for the above, all were prepared under the same conditions as the complex (I).

Further, the composite (IV) was topped with the outer coating rubber composition of Formulation B shown in Table 1 and vulcanized at 165 ° C. for 18 minutes. An adhesion sample (IV) was prepared.

Further, the composite (IV) was topped with the outer coating rubber composition of Formulation B shown in Table 1 so as to have a gauge of 1.15 mm to form a belt layer. Using the belt layer, a tire (IV) was prototyped under the conditions shown in Table 2.

Example 3 In Example 3, the composite (composite (V)) of the steel cord and the rubber composition constituting the inner coating layer was such that the inner coating layer had a thickness of 2.0 mm. Except for the above, all were prepared under the same conditions as the complex (I).

Further, the composite (V) was mixed with the compound B shown in Table 1
, And vulcanized for 18 minutes at 165 ° C. to prepare a wet heat bonding sample (V) in the same manner as in Example 1.

Further, the complex (V) was mixed with the compound B shown in Table 1
And a top layer was formed with a rubber composition having a thickness of 1.15 mm to form a belt layer. Using the belt layer, a tire (V) was prototyped under the conditions shown in Table 2.

Comparative Example 3 In Comparative Example 3, the steel cord was not provided with an inner coating layer.

Then, the steel cord was directly topped with the outer coating rubber composition of Formulation B shown in Table 1,
The sample was vulcanized at 5 ° C. for 18 minutes to prepare a wet heat bonding sample (VI) in the same manner as in Example 1.

Further, a steel cord was directly topped with the outer coating rubber composition of Formulation B shown in Table 1 so as to have a gauge of 1.15 mm to form a belt layer. And
Tire (VI) using the belt layer under the conditions shown in Table 2.
Was prototyped.

[0071] Comparative Example 4 Comparative Example 4, a steel cord, a rubber composition constituting the inner coating layer, the complex of (complex (VII)), rubber inner coating layer formulation C in Table 1 Except for being composed of the composition, all were prepared under the same conditions as the composite (I).

Further, the composite (VII) was topped with the outer coating rubber composition of Formulation B shown in Table 1 and 165 ° C.
Under the conditions of vulcanization for 18 minutes, in the same manner as in Example 1,
A sample for wet heat bonding (VII) was prepared.

Further, the composite (VII) was topped with an outer coating rubber composition of Formulation B shown in Table 1 so as to have a gauge of 1.15 mm to form a belt layer. Then, using the belt layer, the tire (VII) was obtained under the conditions shown in Table 2.
Was prototyped.

Example 4 In Example 4, the composite (composite (VIII)) of the steel cord and the rubber composition constituting the inner coating layer was a rubber having the inner coating layer of the compound D shown in Table 1. Except for being composed of the composition, all were prepared under the same conditions as the composite (I).

Further, the composite (VIII) was topped with the outer coating rubber composition of Formulation B shown in Table 1 and 165
The sample was vulcanized for 18 minutes under the condition of ° C., and a wet heat bonding sample (VIII) was prepared in the same manner as in Example 1.

Further, the composite (VIII) was topped with the outer coating rubber composition of Formulation B shown in Table 1 so as to have a gauge of 1.15 mm to form a belt layer. And
Using the belt layer, a tire (VII) was used under the conditions shown in Table 2.
I) was prototyped.

Example 5 In Example 5, the composite (composite (IX)) of the steel cord and the rubber composition constituting the inner coating layer was a rubber having the inner coating layer of the compound E shown in Table 1. Except for being composed of the composition, all were prepared under the same conditions as the composite (I).

Further, the composite (IX) was topped with the outer coating rubber composition of Formulation B shown in Table 1 and vulcanized at 165 ° C. for 18 minutes. A sample for bonding (IX) was prepared.

Further, the composite (IX) was topped with the outer coating rubber composition of Formulation B shown in Table 1 so as to have a gauge of 1.15 mm to form a belt layer. Using the belt layer, a tire (IX) was prototyped under the conditions shown in Table 2.

Example 6 In Example 6, the composite (composite (X)) of the steel cord and the rubber composition constituting the inner coating layer was obtained by mixing the rubber of the compound F shown in Table 1 with the inner coating layer. Except for the composition,
All were prepared under the same conditions as complex (I).

Further, the complex (X) was mixed with the compound B shown in Table 1
, And vulcanized for 18 minutes at 165 ° C. to prepare a wet heat bonding sample (X) in the same manner as in Example 1.

Further, the complex (X) was mixed with the compound B shown in Table 1
And a top layer was formed with a rubber composition having a thickness of 1.15 mm to form a belt layer. Using the belt layer, a tire (X) was prototyped under the conditions shown in Table 2.

Performance Evaluation <Peeling Test> After the prepared wet heat bonding samples (I) to (X) were left in an oven at 80 ° C. and a relative humidity of 95% for 120 hours, a cut 14 was made as shown in FIG. And peeling was started from the peeling position 16 to perform a peeling test. The peel test was also performed after leaving the prepared sample for wet heat bonding for 0 hour.

The peeled surface 18 shown in FIG. 4B was visually observed, and the results of the peel test were evaluated based on the evaluation criteria shown in Table 3.
It is shown in Tables 4 and 5 as a single-digit number. Table 4,
In Table 5, the rubber composition of the inner coating layer, the thickness of the inner coating layer, and the rubber composition of the outer coating layer, which constitute the composite of the steel cord and the rubber composition, are also shown.

[0085]

[Table 3]

[0086]

[Table 4]

[0087]

[Table 5]

<High-speed running durability test> A high-speed running durability test was performed using the prototype tires (I) to (X). Using a drum tester, adjust the ambient temperature to 25 ± 5 ° C., attach the tires (I) to (X) to the rim, and set the internal pressure to 280.
Running speed of 170k under kPa and load of 492kg
The speed is increased step by step at a speed of 10 km / h every 10 minutes, and the vehicle is driven until a failure occurs. Then, the running distance until the occurrence of the failure is indicated by an index with Comparative Example 1 being 100. The higher the index, the better the high-speed running durability. The test results are shown in Tables 6 and 7. Tables 6 and 7 also show the rubber composition of the inner coating layer, the thickness of the inner coating layer, and the rubber composition of the outer coating layer, which constitute the composite of the steel cord and the rubber composition.

[0089]

[Table 6]

[0090]

[Table 7]

<Cost evaluation> In addition, the prototype tire (I) ~
For (X), the production cost was also evaluated. Tables 6 and 7 show the results of the evaluation. The cost evaluations in Tables 6 and 7 are indicated as very low (◎), low (○), high (△), and very high (×).

<Evaluation Results> From the results of the peeling test, it was found that the composite of the steel cord and the rubber composition according to the present invention had good initial adhesion and deterioration-resistant adhesion between the steel cord and the rubber composition. all right. From the results of the high-speed running durability test, it was found that the tire using the composite of the steel cord and the rubber composition according to the present invention as a reinforcing material had excellent durability. Further, from the results of the cost evaluation, it was also found that the tire using the composite of the steel cord and the rubber composition according to the present invention as a reinforcing material can reduce the manufacturing cost.

The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0094]

The composite of a steel cord and a rubber composition according to the present invention is a composite of a steel cord and a rubber composition comprising a coating layer and a steel cord, wherein the coating layer comprises
A rubber component, a cobalt compound, and an inner coating layer which is made of a rubber composition containing sulfur and directly coats the steel cord, the content of the cobalt compound and sulfur is smaller than the content in the inner coating layer. It has a unique structure characterized by being composed of a rubber composition and an outer coating layer wrapping the outside of the inner coating layer.With such a structure, the initial adhesion to the steel cord of the rubber composition and It has become possible to ensure good degradation resistance. The tire using the composite of the steel cord and the rubber composition has excellent durability and economical production cost.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating one embodiment of a steel cord according to the present invention.

FIG. 2 is a diagram illustrating another embodiment of the steel cord according to the present invention.

FIG. 3 is a diagram illustrating a process of manufacturing a steel cord according to the present invention.

FIG. 4 (A) illustrates a method for preparing a wet heat bonding sample for evaluating the performance of a composite of a steel cord and a rubber composition according to the present invention, and (B) illustrates a method for a peel test of the wet heat bonding sample. FIG.

[Explanation of symbols]

1,21 steel wire, 2,22 inner coating layer,
3, 23 outer coating layer, 4A, 4B, 4C unwind drum, 5, 6A, 6B, 7A, 7B, 7C, 7D, 8A,
8B drum, 9 winding drum, 10, 20 Composite of steel cord and rubber composition, 12 Steel cord or composite of steel cord and rubber composition, 14 Cut, 16 Peeling position, 18 Peeling surface, 33, 33a
Outer coating rubber composition.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor: Attack Toda 3-6-9, Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo F-term (reference) 4F100 AB03A AL05B AL05C AN00B AN00C BA03 BA10B BA10C BA27 CA02B CA02C GB90 JL11 YY00B YY00C 4J002 AC001 AC011 AC061 AC091 BB151 BB181 DA048 DA086 EG047 FA046 FB266 FD148 FD207 GN01

Claims (5)

[Claims] 1. A composite of a steel cord and a rubber composition comprising a coating layer and a steel cord, wherein the coating layer comprises:
A rubber component, a cobalt compound, and an inner coating layer which is made of a rubber composition containing sulfur and directly coats the steel cord, the content of the cobalt compound and sulfur is smaller than the content in the inner coating layer. A composite of a steel cord and a rubber composition, comprising a rubber composition and an outer coating layer surrounding the outside of the inner coating layer. 2. The rubber composition constituting the inner coating layer contains 0.5 to 5 parts by weight of a cobalt compound and 3 to 8 parts by weight of sulfur based on 100 parts by weight of a rubber component. A composite of the steel cord according to claim 1 and a rubber composition. 3. A composite of a steel cord and a rubber composition according to claim 1, wherein the cobalt compound is a cobalt salt of an organic acid. 4. The method according to claim 1, wherein the thickness of the inner coating layer of the rubber composition is 0.1 to 1.5 mm.
A composite of the steel cord and the rubber composition according to any one of claims 1 to 3. 5. A tire using the composite of the steel cord and the rubber composition according to claim 1.