JP7045181B2 - Metal cord-rubber complex, tire belts, tire carcass and tires - Google Patents

Description

The present invention relates to metal cord-rubber complexes, tire belts, tire carcass and tires.

Conventionally, for rubber articles such as tires, conveyor belts, rubber crawlers, hoses, etc., which require strength, a metal cord such as a steel cord is coated with a rubber composition for the purpose of reinforcing the rubber and improving the strength and durability. A metal cord-rubber composite is used. Here, in order for the metal cord-rubber composite to exhibit high strength and durability, it is necessary to strongly bond the metal cord and the rubber composition.

For example, in a tire, a metal cord-rubber formed by twisting a plurality of brass-plated steel wires or by coating a steel cord made of a single wire of steel wires with a rubber composition (coated rubber). The composite is applied to tire belts and carcass, and is mainly reinforced with steel cords. Here, in order to utilize the steel cord as a reinforcing material for a tire, it is necessary to firmly bond the steel cord to the rubber covering the steel cord, and for this purpose, brass (brass:: brass:) is formed on the peripheral surface of the wire constituting the steel cord. Cu, Zn) plating is usually applied. The adhesiveness between the brass plating layer and the coated rubber is developed by forming an adhesive layer (a layer containing CuS ₂ or CuS) between the ff plating layer and the coated rubber in the coated rubber during vulcanization. It is known. However, the adhesiveness may not be sufficient only by applying brass plating to the peripheral surface of the steel wire.
On the other hand, in order to improve the adhesiveness between the steel cord and the coated rubber, it has been proposed to add an organic cobalt salt to the rubber composition for the coated rubber. However, the organic cobalt salt has a problem that it is expensive and easily deteriorates the unvulcanized rubber.

On the other hand, according to International Publication No. 2014/192811 (Patent Document 1), a metal cord-rubber composite obtained by coating a rubber composition on a metal cord has two N atoms on the surface of the metal cord. A metal cord-rubber composite characterized by having an atomic% or more and 60 atomic% or less and a Cu / Zn ratio of 1 or more and 4 or less is disclosed, and the metal cord-rubber composite is rubber-deteriorated. It is also disclosed that the rubber has excellent initial adhesiveness, water and oxygen deterioration resistance, and adhesiveness after being left in the treat, without causing problems such as crack growth resistance and rubber physical properties.

International Publication No. 2014/192811

However, as a result of examination by the present inventor, even in the metal cord-rubber composite described in Patent Document 1, when the content of the organic cobalt salt in the coated rubber is low, between the metal cord and the coated rubber. On the other hand, when the content of the organic cobalt salt in the coated rubber is increased, the crack resistance of the coated rubber is lowered, so that the initial adhesiveness between the metal cord and the coated rubber and the coating are reduced. It was found that it is necessary to develop a technology that is highly compatible with the crack resistance of rubber.

Therefore, the present invention solves the above-mentioned problems of the prior art, and is capable of highly achieving both the initial adhesiveness between the metal cord and the coated rubber and the crack resistance of the coated rubber. The subject is to provide a complex.
Further, it is a further object of the present invention to provide a tire belt, a tire carcass and a tire having excellent durability using such a metal cord-rubber composite.

The gist structure of the present invention for solving the above problems is as follows.

The metal cord-rubber complex of the present invention is a metal cord-rubber composite obtained by coating a metal cord with a rubber composition.
The N atom on the surface of the metal cord is 2 atomic% or more and 60 atomic% or less, and the Cu / Zn ratio is 1 or more and 4 or less on a mass basis.
The rubber composition is characterized by containing a rubber component, a filler, and a bismaleimide compound.
The metal cord-rubber composite of the present invention can highly achieve both the initial adhesiveness between the metal cord and the rubber composition (coated rubber) and the crack resistance of the coated rubber.

In a preferred example of the metal cord-rubber complex of the present invention, the rubber composition further comprises a tackifier. In this case, the workability of the metal cord-rubber complex is excellent.

Here, the tackifier is preferably a phenolic resin. In this case, the workability of the metal cord-rubber complex is further improved.

In the metal cord-rubber composite of the present invention, the rubber composition preferably has a cobalt content of 0 to 1 part by mass with respect to 100 parts by mass of the rubber component. In this case, the crack resistance of the metal cord-rubber complex is sufficiently good.

In another preferred example of the metal cord-rubber complex of the present invention, the bismaleimide compound is 4,4'-diphenylmethane bismaleimide. In this case, the initial adhesiveness between the metal cord and the rubber composition (coated rubber) is further improved.

Further, the tire belt of the present invention is characterized in that the above-mentioned metal cord-rubber composite is used. The tire belt of the present invention has excellent durability.

Further, the carcass for a tire of the present invention is characterized in that the above-mentioned metal cord-rubber composite is used. The carcass for tires of the present invention is excellent in durability.

Further, the tire of the present invention is characterized in that the above-mentioned metal cord-rubber composite is used. The tire of the present invention has excellent durability.

According to the present invention, it is possible to provide a metal cord-rubber composite capable of highly achieving both the initial adhesiveness between the metal cord and the coated rubber and the crack resistance of the coated rubber.
Further, according to the present invention, it is possible to provide a tire belt, a tire carcass and a tire having excellent durability using such a metal cord-rubber composite.

Hereinafter, the metal cord-rubber composite, the tire belt, the tire carcass, and the tire of the present invention will be illustrated in detail based on the embodiments thereof.

<Metal cord-rubber complex>
The metal cord-rubber composite of the present invention is a metal cord-rubber composite in which the metal cord is coated with a rubber composition, and the N atoms on the surface of the metal cord are 2 atomic% or more and 60 atomic% or less. Moreover, the Cu / Zn ratio is 1 or more and 4 or less on a mass basis, and the rubber composition is characterized by containing a rubber component, a filler, and a bismaleimide compound.

In the metal cord-rubber composite of the present invention, since a metal cord having an N atom on the surface of 2 atomic% or more and 60 atomic% or less and a Cu / Zn ratio of 1 or more and 4 or less on a mass basis is used, it is usually used. The initial adhesion between the metal cord and the rubber composition is higher than when the metal cord of the above is used. Further, in the metal cord-rubber composite of the present invention, the initial adhesiveness between the metal cord and the coated rubber is further improved by containing the bismaleimide compound in the rubber composition (coated rubber) that coats the metal cord. do.
Further, in the metal cord-rubber composite of the present invention, the initial adhesiveness between the metal cord and the coated rubber is sufficiently high, so that the rubber composition (coated rubber) does not need to contain an organic cobalt salt. Therefore, in the metal cord-rubber composite of the present invention, it is possible to reduce the blending amount of the organic cobalt salt in the rubber composition (covered rubber) or not to blend the organic cobalt salt, whereby the rubber composition can be blended. The crack resistance of (coated rubber) can be improved.
Therefore, according to the metal cord-rubber composite of the present invention, it is possible to highly achieve both the initial adhesiveness between the metal cord and the coated rubber and the crack resistance of the coated rubber.

In the metal cord-rubber composite of the present invention, the metal cord has N atoms on the surface of 2 atomic% or more and 60 atomic% or less, and a Cu / Zn ratio of 1 or more and 4 or less on a mass basis.
As the metal cord, one made by twisting a plurality of metal wires (metal steel wires) or one made of a single metal wire is preferable.
The metal wire is not particularly limited, and examples thereof include wires such as iron, steel (stainless steel), lead, aluminum, copper, brass, bronze, Monel metal alloy, nickel, and zinc.
Further, the metal wire preferably has a plating layer produced by a conventional method on its surface, and the plating layer is not particularly limited, but for example, a zinc plating layer, a copper plating layer, or a brass plating layer. And so on. Among these, a brass plating layer is preferable from the viewpoint of initial adhesiveness to the rubber composition and wet-heat adhesiveness.
The bulk brass plating composition constituting the brass plating layer contains 40 to 80% by mass of Cu (copper) and 20 by mass of Zn (zinc) from the viewpoint of workability of the steel cord and adhesion to the coated rubber. It is preferably ~ 60% by mass, more preferably 55 to 70% by mass of Cu and 30 to 45% by mass of Zn.

As the metal wire, a steel wire will be mentioned and will be described in more detail.
The steel wire is steel, that is, a linear metal containing iron as a main component (the mass of iron exceeds 50% by mass with respect to the total mass of the metal steel wire). The metal may contain a metal other than iron.
From the viewpoint of workability and durability, the steel wire preferably has a wire diameter of 0.1 mm to 5.5 mm, more preferably 0.15 mm to 5.26 mm. Here, the wire diameter of the steel wire means the longest length between two points on the outer circumference in a cross-sectional shape perpendicular to the axis of the steel wire. The cross-sectional shape perpendicular to the axis of the steel wire is not particularly limited and may be elliptical, rectangular, triangular, polygonal or the like, but is generally circular. When a steel cord, which is a metal reinforcing cord obtained by twisting the steel wire into a tire carcass or belt, is used, the cross-sectional shape of the steel wire is circular and the wire diameter is 0.1 mm to 0.5 mm. When used for a bead core of a tire, the cross-sectional shape is similarly circular, and the wire diameter is preferably 1 mm to 1.5 mm. Further, the steel wire preferably has a brass plating layer having the above composition on its surface, and the thickness of the plating layer is not particularly limited, but is generally 100 to 300 nm, for example.

In the present invention, for example, a plurality of metal wires such as steel wires having the above-mentioned brass plating on the peripheral surface are twisted together, for example, by twisting them into a 1 × 3 structure, a 1 × 5 structure, or the like, by a conventional method. A metal cord consisting of can be obtained.
The metal cord suitable for reinforcing a rubber article such as a steel cord is preferably at least one selected from the group consisting of a belt cord for a tire, a carcass cord and a bead cord.

The N (nitrogen) atom on the surface of the metal cord needs to be 2 atomic% or more and 60 atomic% or less, and the Cu / Zn ratio needs to be 1 or more and 4 or less on a mass basis, preferably a metal. The N atoms on the surface of the cord are 2.1 atomic% or more and 55.0 atomic% or less, and the Cu / Zn ratio is 1.1 or more and 3.5 or less.
By setting the ratio of N atoms on the surface of the metal cord to 2 atomic% or more, the initial adhesiveness with the coated rubber is improved, while when it is less than 2 atomic%, the treat leaving property is deteriorated, and 60 atomic% is used. If it exceeds, the initial adhesiveness with the coated rubber deteriorates. Further, by setting the Cu / Zn ratio on the surface of the metal cord to 1 or more, the initial adhesiveness with the coated rubber is improved, while when it is less than 1, the initial adhesiveness is not sufficient, and when it is 4 or less. , The initial adhesiveness becomes good, and if it exceeds 4, the wet heat deterioration property becomes insufficient.
The adjustment to adjust the N (nitrogen) atom on the surface of the metal cord to 2 atomic% or more and 60 atomic% or less is, for example, treatment with a triazole compound (rust inhibitor), specifically, contact with an aqueous solution of the triazole compound, etc. It can be carried out by a suitable combination of the surface treatments of. Further, the adjustment to make the Cu / Zn ratio on the surface of the metal cord 1 or more and 4 or less can be performed, for example, by subjecting a treatment suitablely combining the pH of the acidic buffer solution and the concentration of the triazole aqueous solution. The lower the pH, the higher the Cu / Zn ratio of the metal cord can be obtained.

Examples of the acid buffer include an acetate buffer having a pH of 5.0 to 7.2, a phosphate buffer solution, a citrate buffer solution and the like, and an acetate buffer solution having a pH of 5.0 to 7.2 is preferable. When the pH is less than 5.0, it becomes difficult to make the Cu / Zn ratio 4 or less, and when the pH exceeds 7.2, it becomes difficult to make the Cu / Zn ratio 1 or more. The surface treatment time with this buffer solution can be, for example, 0.5 to 20 seconds when an acetate buffer solution having a pH of 5.0 to 7.2 is used.

Examples of the triazole aqueous solution include 1,2,4-triazole, 1,2,3-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole. Examples thereof include an aqueous solution containing one or more triazole compounds selected from benzotriazole, tolyltriazole, and 3-mercapto-1,2,4-triazole. Among these, the water-soluble substances of 1,2,4-triazole, 1,2,3-triazole, 3-amino-1,2,4-triazole and 4-amino-1,2,4-triazole should be used. Is preferable. The concentration of the triazole aqueous solution is preferably 0.01 to 20 g / L, and the treatment time can be 0.1 to 30 seconds, although it varies depending on the concentration.

In the present invention, the "surface" is a surface layer region up to a depth of 5 nm inward in the radial direction of a metal wire such as a steel wire. The measurement of N atoms on the surface of the metal cord and the measurement of the Cu / Zn ratio are performed after obtaining the metal cord, performing cleaning treatment, drying and the like as necessary, and before coating with the rubber composition. It measures the surface of a metal cord.
Further, in the present invention (including examples described later), the N atom on the surface of the metal cord is measured by the X-ray photoelectron spectroscopy (XPS) method. The atom is measured, and the Cu / Zn ratio on the surface of the metal cord is measured by the above-mentioned photoelectron spectroscopy to measure the Cu / Zn ratio on the surface of the metal cord.

In the metal cord-rubber composite of the present invention, the rubber component of the rubber composition (hereinafter, may be referred to as “coated rubber”) that coats the metal cord is not particularly limited, and is, for example, natural rubber or polybutadiene. Rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, ethylene-propylene copolymer rubber, ethylene-propylene-dienter polymer rubber, butyl rubber, halogenated butyl rubber, alkylated chlorosulfonated Examples thereof include polyethylene rubber, isobutylene-isoprene copolymer rubber, and diene rubber such as polychloroprene rubber. Among these rubber components, natural rubber and polyisoprene rubber are preferable from the viewpoint of crack resistance of the coated rubber. These rubber components may be used alone or in combination of two or more.

In the metal cord-rubber composite of the present invention, the rubber composition covering the metal cord contains a filler. The filler is not particularly limited, and examples thereof include carbon black, silica, aluminum hydroxide, alumina, clay, calcium carbonate and the like. Among these, carbon blank and silica are preferable, and carbon black is particularly preferable, from the viewpoint of crack resistance of the coated rubber.
The carbon black is not particularly limited, and examples thereof include GPF, FEF, HAF, ISAF, and SAF grade carbon black. The silica is not particularly limited, and examples thereof include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate.
The blending amount of the filler is preferably in the range of 20 to 100 parts by mass, more preferably in the range of 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component. When the blending amount of the filler is 20 parts by mass or more with respect to 100 parts by mass of the rubber component, the strength of the rubber composition is sufficiently improved, and when it is 100 parts by mass or less, the rubber composition is mixed. Good workability in kneading.

で表される化合物が好ましい。
ここで、式（１）中、Ｘは、炭素数２～４のアルキレン基、フェニレン基、又は芳香族環を１～４有する炭素数６～２９の２価の炭化水素基を表し、Ｒ^１～Ｒ^４は、それぞれ独立して、水素原子、炭素数１～５のアルキル基、－ＮＨ_２基又は－ＮＯ_２基を表す。 In the metal cord-rubber composite of the present invention, the rubber composition covering the metal cord contains a bismaleimide compound. The bismaleimide compound has an action of improving the initial adhesiveness between the metal cord and the coated rubber. The bismaleimide compound has the following formula (1):

The compound represented by is preferable.
Here, in the formula (1), X represents an alkylene group having 2 to 4 carbon atoms, a phenylene group, or a divalent hydrocarbon group having 6 to 29 carbon atoms having 1 to 4 aromatic rings, and R ¹ ~ R ⁴ independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, _two -NH groups or _two -NO groups.

In the above formula (1), examples of the alkylene group having 2 to 4 carbon atoms which are X include an ethylene group, a propylene group, a propane-2,2-diyl group and the like. Examples of the divalent hydrocarbon group having 1 to 4 aromatic rings and 6 to 29 carbon atoms include a methylenebis (phenylene) group, a phenylenebis (methylene) group, and a phenoxyphenyl group. Further, this aromatic ring may be bonded by -O-, -S-, -SS-, -SO _2- or the like. Among the above X, a hydrocarbon group having 1 or 2 phenylene groups and an aromatic ring and having 8 to 17 carbon atoms is preferable, and a hydrocarbon having 1 or 2 phenylene groups or an aromatic ring and having 8 to 13 carbon atoms is preferable. Groups are more preferred. In the above formula (1), X may have a substituent. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms, -NH ₂ , -NO ₂ , -F, -Cl, -Br and the like.

Further, in the above formula (1), examples of the alkyl group having 1 to 5 carbon atoms represented by R ¹ to R ⁴ include a methyl group, an ethyl group, a propyl group and the like. As R ¹ to R ⁴ , a hydrogen atom is preferable.

Preferable examples of the bismaleimide compound include, for example, 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, N, N'-1,2-ethylene bismaleimide, N, N'-1,2-propylene. Bismaleimide, bis (3-ethyl-5-methyl-4-maleimidephenyl) methane, 2,2'-bis [4- (4-maleimidephenoxy) phenyl] propane, m-phenylenebis (methylene) bismaleimide, m -Phenylene bis (methylene) biscitraconimide, 1,1'-(methylenedi-4,1-phenylene) bismaleimide and the like can be mentioned. These bismaleimide compounds may be used alone or in combination of two or more.
Among these, 4,4'-diphenylmethanebismaleimide and m-phenylenebismaleimide are preferable, and 4,4'-diphenylmethanebismaleimide is preferable from the viewpoint of initial adhesion between the metal cord and the rubber composition (coated rubber). Is particularly preferable.

The blending amount of the bismaleimide compound is preferably in the range of 0.05 to 5.5 parts by mass, more preferably in the range of 0.05 to 3.5 parts by mass, and 0.1 by mass with respect to 100 parts by mass of the rubber component. The range of ~ 1.0 part by mass is even more preferable. When the blending amount of the bismaleimide compound is 0.1 part by mass or more with respect to 100 parts by mass of the rubber component, the effect of improving the initial adhesiveness becomes large, and when it is 5.5 parts by mass or less, the rubber The elastic modulus of the composition can be increased, and the wet-heat adhesion of the metal cord-rubber composite can be improved.

The rubber composition covering the metal cord preferably further contains a tackifier. When the rubber composition covering the metal cord contains a tackifier, the workability of the metal cord-rubber complex is improved. More specifically, when the rubber composition contains a tackifier, it is possible to provide a rubber composition having excellent tackiness when adhering to other members during molding of a tire or the like, and to improve the productivity of the tire or the like. Connect.

Various natural resins and synthetic resins can be used as the tackifier, and specifically, rosin-based resin, terpene-based resin, petroleum-based resin, phenol-based resin, coal-based resin, xylene-based resin and the like can be used. It is preferable to use. These tackifiers may be used alone or in combination of two or more.

In the natural resin, examples of the rosin-based resin include gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, modified rosin glycerin, and pentaerythritol ester.
In the natural resin, examples of the terpene-based resin include α-pinene-based, β-pinene-based, and dipentene-based terpene resins, aromatic-modified terpene resins, terpene phenol resins, and hydrogenated terpene resins.
Among these natural resins, polymerized rosin, terpene phenol resin, and hydrogenated terpene resin are preferable from the viewpoint of fracture resistance of the blended rubber composition.

In the synthetic resin, the petroleum-based resin is a decomposed oil distillate containing unsaturated hydrocarbons such as olefins and diolefins that are by-produced together with basic petrochemical raw materials such as ethylene and propylene by, for example, thermal decomposition of naphtha in the petrochemical industry. Is obtained by polymerizing the mixture as it is with a Friedelcraft type catalyst. The petroleum-based resin includes an aliphatic petroleum resin (so-called C5 _- based resin) obtained by (copolymerizing) a C5 distillate obtained by thermal decomposition of naphtha, and C ₉ obtained by thermal decomposition of naphtha _. An aromatic petroleum resin (so-called C9-based resin) obtained by (co) polymerizing a distillate, and a copolymerized petroleum resin (so-called so-called _{C9 -} based resin) obtained by copolymerizing the C5 distillate and the _C9 distillate. C5- _{C9 -} based resin), alicyclic compound-based petroleum resin such as hydrogenated or dicyclopentadiene-based, styrene, substituted styrene, or styrene-based resin such as a copolymer of styrene and another monomer. Be done.

The C5 distillate obtained by thermal decomposition of naphtha is usually olefinic such as 1 _- pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene. Diolefin hydrocarbons such as hydrocarbons, 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene and 3-methyl-1,2-butadiene are included. The aromatic petroleum resin obtained by (co) polymerizing the _C9 distillate is a resin obtained by polymerizing an aromatic having 9 carbon atoms having vinyltoluene and indene as main monomers, and is obtained by thermal decomposition of naphtha. Specific examples of the obtained _C9 distillate include styrene homologues such as α-methylstyrene, β-methylstyrene and γ-methylstyrene, and inden homologues such as indene and kumaron. Examples of the petroleum-based resin include petrodin manufactured by Mitsui Petrochemical Co., Ltd., petrite manufactured by Mikuni Chemical Co., Ltd., neopolymer manufactured by Nippon Petrochemical Co., Ltd., and petroleum manufactured by Toyo Soda.

It is also preferable to use a modified petroleum resin obtained by modifying the petroleum resin composed of the _C9 distillate. Examples of the modified petroleum resin include a _C9 -based petroleum resin modified with an unsaturated alicyclic compound, a _C9 -based petroleum resin modified with a compound having a hydroxyl group, and a _C9 -based petroleum resin modified with an unsaturated carboxylic acid compound. Can be mentioned.

Preferred unsaturated alicyclic compounds include cyclopentadiene, methylcyclopentadiene and the like. Further, as the unsaturated alicyclic compound, a Diels-Alder reaction product of alkylcyclopentadiene is also preferable, and as the Diels-Alder reaction product of the alkylcyclopentadiene, a dicyclopentadiene and a cyclopentadiene / methylcyclopentadiene codimiation product are used. , Tricyclopentadiene and the like. Dicyclopentadiene is particularly preferable as the unsaturated alicyclic compound. The dicyclopentadiene-modified _C9 -based petroleum resin can be obtained by thermal polymerization or the like in the presence of both the dicyclopentadiene and the _C9 fraction. Examples of the dicyclopentadiene-modified _C9 -based petroleum resin include Neopolymer 130S (manufactured by Nippon Petrochemicals Co., Ltd.).

Examples of the compound having a hydroxyl group include an alcohol compound and a phenol compound. Specific examples of the alcohol compound include alcohol compounds having a double bond such as allyl alcohol and 2-butene-1,4diol. As the phenol compound, alkylphenols such as phenol, cresol, xylenol, p-tert-butylphenol, p-octylphenol and p-nonylphenol can be used. These compounds having a hydroxyl group may be used alone or in combination of two or more. Further, the _C9 -based petroleum resin having a hydroxyl group is a method of thermally polymerizing a (meth) acrylic acid alkyl ester or the like together with an petroleum distillate to introduce an ester group into the petroleum resin, and then reducing the ester group. It can be produced by a method of hydrating the double bond after the double bond remains or is introduced therein. As the _C9 -based petroleum resin having a hydroxyl group, those obtained by various methods as described above can be used, but from the viewpoint of performance and production, it is preferable to use a phenol-modified petroleum resin or the like. The phenol-modified petroleum resin is obtained by cationically polymerizing a _C9 fraction in the presence of phenol, is easy to modify, and is inexpensive. Examples of the phenol-modified _C9 petroleum resin include neopolymer E-130 (manufactured by Nippon Petrochemicals Co., Ltd.).

Further, the _C9 -based _petroleum resin modified with the unsaturated carboxylic acid compound can be modified with an ethylenically unsaturated carboxylic acid. Typical examples of such ethylenically unsaturated carboxylic acid include (maleic) maleic acid, fumaric acid, itaconic acid, tetrahydro (anhydrous) futal acid, (meth) acrylic acid and citraconic acid. The unsaturated carboxylic acid-modified _C9 -based petroleum resin can be obtained by thermally polymerizing a _C9 -based petroleum resin and an ethylene-based unsaturated carboxylic acid. Examples of the unsaturated carboxylic acid-modified _C9 petroleum resin include Neopolymer 160 (manufactured by Shin Nihon Petrochemical).

In the synthetic resin, examples of the phenol-based resin include phenol formaldehyde resin, alkylphenol formaldehyde resin and its rosin modified product, alkylphenol acetylene resin, modified alkylphenol resin, and terpenephenol resin. Specific examples of the phenolic resin include OR-50235 (phenol formaldehyde resin) manufactured by Sumitomo Bakelite, Hitanol 1502 (novolak type alkylphenol resin) manufactured by Hitachi Chemical Industries, and choresin (p-tert-) manufactured by BASF. Butylphenol acetylene resin) and the like.

In the synthetic resin, examples of the coal-based resin include kumaron inden resin, and examples of the xylene-based resin in the synthetic resin include xylene formaldehyde resin. In addition, other polybutenes can also be used as a resin having adhesiveness.

Among the tackifiers, it is obtained by (co) polymerizing a copolymer resin of C5 fraction and _C9 fraction, and _C9 fraction from the viewpoint of workability ₍ tackiness) of the blended rubber composition. Aromatic petroleum resins, phenolic resins and Kumaron inden resins are preferred. Further, from the viewpoint of workability (tackiness) of the metal cord-rubber complex, a phenolic resin is preferable, and an alkylphenol resin is particularly preferable.

The blending amount of the tackifier is preferably in the range of 0.1 to 10 parts by mass, more preferably in the range of 0.1 to 5 parts by mass, and 0.1 to 3 parts by mass with respect to 100 parts by mass of the rubber component. Is even more preferred, and the range of 0.3 to 1.0 parts by mass is even more preferred. When the content of the tackifier is 0.1 part by mass or more with respect to 100 parts by mass of the rubber component, the workability (tackiness) of the rubber composition is sufficiently improved, and when it is 10 parts by mass or less. For example, the tackiness does not become too high, and the crack resistance of the rubber composition can be sufficiently improved.

In the metal cord-rubber composite of the present invention, the rubber composition covering the metal cord may or may not contain cobalt. Here, the content of cobalt in the rubber composition is preferably in the range of 0 to 1 part by mass, more preferably in the range of 0 to 0.5 part by mass, and 0 part by mass with respect to 100 parts by mass of the rubber component. The range of more than 0.1 parts by mass is even more preferable. In the metal cord-rubber composite of the present invention, even if the content of cobalt in the rubber composition covering the metal cord is 0 parts by mass, sufficient initial adhesiveness is obtained due to the above-mentioned compounding effect of the bismaleimide compound. Is obtained. On the other hand, when the content of cobalt in the rubber composition covering the metal cord is 1 part by mass or less with respect to 100 parts by mass of the rubber component, the crack resistance of the metal cord-rubber composite can be sufficiently improved.

When the rubber composition contains cobalt, the cobalt can be contained in the rubber composition as an organic cobalt salt. Here, examples of the organic cobalt salt include cobalt fatty acid salts such as cobalt naphthenate, cobalt stearate, cobalt neodecanoate, cobalt loginate, cobalt versatic acid, and cobalt tall oil. The cobalt fatty acid salt may be a complex salt in which a part of the fatty acid portion is replaced with boric acid or the like.

The rubber composition covering the metal cord preferably further contains a vulcanizing agent. Examples of the vulcanizing agent include sulfur and the like.
The content of the vulcanizing agent is preferably in the range of 1 to 10 parts by mass and more preferably in the range of 3 to 8 parts by mass as the sulfur content with respect to 100 parts by mass of the rubber component. If the content of the vulcanizing agent is 1 part by mass or more as the sulfur content with respect to 100 parts by mass of the rubber component, the crack resistance of the coated rubber is improved, and if it is 10 parts by mass or less, the rubber Sufficient elasticity can be secured.

In addition to the above-mentioned components, a compounding agent usually used in the rubber industry may be appropriately added to the rubber composition covering the metal cord as long as the object of the present invention is not impaired. Examples of such compounding agents include vulcanization accelerators, antiaging agents, zinc oxide (zinc oxide), stearic acid, softeners and the like.
The rubber composition can be produced by blending a rubber component with a filler and a bismaleimide compound, as well as various compounding agents appropriately selected as necessary, and kneading, heating, extruding, or the like.

In the production of the metal cord-rubber composite of the present invention, for example, the metal cord subjected to each of the above surface treatments is subjected to a cleaning treatment by a conventional method as necessary, and then the metal cord and the above coating are used. It can be manufactured through a step of adhering it to a rubber composition. Here, as a method of adhering the metal cord and the rubber composition, for example, a method of vulcanizing and adhering the metal cord and the rubber composition under pressure and heating can be mentioned. The vulcanization conditions are not particularly limited, but the pressure is preferably 2 MPa to 15 MPa, more preferably 2 MPa to 5 MPa, and the temperature is preferably 120 to 200 ° C., more preferably 130 to 170 ° C. The vulcanization time is not particularly limited, but is preferably 3 minutes to 60 hours.

The metal cord-rubber composite of the present invention is not particularly limited, but is not limited to tires for automobiles, dynamic transmission belts, industrial belts such as conveyor belts, rubber crawler, hoses, and rubber bearings for seismic isolation. It can be widely used for various rubber products and parts such as.

<Tire belt>
The tire belt of the present invention is characterized in that the above-mentioned metal cord-rubber composite is used. The tire belt of the present invention uses the metal cord-rubber composite which can highly achieve both the above-mentioned initial adhesion between the metal cord and the coated rubber and the crack resistance of the coated rubber. Therefore, it has excellent durability.

<Carcass for tires>
The carcass for a tire of the present invention is characterized by using the above-mentioned metal cord-rubber composite. In the tire carcass of the present invention, the above-mentioned metal cord-rubber composite capable of highly achieving both the initial adhesiveness between the metal cord and the coated rubber and the crack resistance of the coated rubber is used. Therefore, it has excellent durability.

<Tire>
The tire of the present invention is characterized by using the above-mentioned metal cord-rubber complex. Since the tire of the present invention uses the metal cord-rubber composite which can highly balance the above-mentioned initial adhesiveness between the metal cord and the coated rubber and the crack resistance of the coated rubber. Has excellent durability. Here, in the tire of the present invention, examples of the application site of the metal cord-rubber complex include a belt, a carcass, a bead core, and the like.

The tire of the present invention may be obtained by vulcanization after molding using an unvulcanized rubber composition or a metal cord-rubber composite, or an unvulcanized rubber composition, depending on the type of tire to be applied. It may be obtained by molding using a semi-crosslinked rubber composition (semi-vulcanized rubber) that has undergone a preliminary vulcanization step or the like together with a substance or a metal cord-rubber composite, and then further performing main vulcanization. Here, when the rubber composition covering the metal cord contains a tackifier, the metal cord-rubber composite is excellent in adhesiveness (tackiness) with a rubber member made of an unvulcanized rubber composition, and is used in the molding process. Because of the high workability in the tire, the productivity of the tire can be improved.
The tire of the present invention is preferably a pneumatic tire, and as the gas to be filled in the pneumatic tire, an inert gas such as nitrogen, argon, or helium is used in addition to normal or adjusted oxygen partial pressure. Can be used.

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

(Making metal cord)
A steel cord having a 1 × 3 structure was produced by twisting brass-plated steel wires having the compositions shown in Table 1 (plating layer thickness 0.2 μm, wire diameter 0.3 mm). Next, this code was washed with a treatment liquid consisting of treatment 1: acetate buffer and treatment 2: rust preventive (triazole compound), which is a treatment method shown below, and dried at 50 ° C. for 1 minute. The N amount (outermost surface N amount: atomic%) and Cu / Zn ratio (outermost surface Cu / Zn ratio, mass standard) of the wire-plated surface of the steel cord after this cleaning process are determined by the X-ray photoelectron spectrometer (ULVAC-PHI). It was measured by Quantera) manufactured by Quantera Co., Ltd. The results are shown in Table 1.
The measurement conditions by X-ray photoelectron spectroscopy are as follows.
X-ray source: Monochromatic Al-Kα ray Measurement area: 50 μmΦ
Measurement peaks: C1s, O1s, N1s, P2p, Cu2p2 / 3, Zn2p2 / 3
Data processing: Multipak (manufactured by ULVAC-PHI, Inc.)
Quantitative: Quantitative from the obtained peak area using the relative sensitivity coefficient method * Cu / Zn ratio is the ratio of the quantitative values of Cu2p2 / 3 and Zn2p2 / 3.

<Treatment 1: Treatment with acetate buffer>
As a treatment with an acetate buffer, the prepared steel cord was washed with a treatment solution prepared by adjusting 0.1N sodium acetate with acetic acid to have the pH shown in Table 1 for a treatment time of 10 seconds, and surface treatment was performed. rice field.

<Treatment 2: Treatment with triazole compound (rust inhibitor)>
As a treatment with a triazole compound (rust inhibitor), the prepared steel cord was washed with a triazole compound aqueous solution adjusted to each concentration using the triazole compound shown in Table 1 for a treatment time of 10 seconds for surface treatment. Was done.

(Metal cord-rubber complex fabrication and evaluation)
A rubber composition was produced using a normal Banbury mixer according to the formulation shown in Table 1. A metal cord-rubber complex was prepared using the obtained rubber composition and the steel cord subjected to the above-mentioned cleaning treatment, and by the following methods, (1) initial adhesiveness, (2) crack resistance and (3) Workability was evaluated. The results are shown in Table 1.

(1) Initial Adhesiveness The above-cleaned steel cords are arranged in parallel at 12.5 mm intervals, the steel cords are coated with a rubber composition from above and below, and vulcanized at 160 ° C. for 7 minutes to obtain a rubber composition. By adhering to the steel cord, a metal cord-rubber composite was obtained in which the steel cord was embedded in a rubber sheet having a thickness of 1 mm (the steel cord was in the center of the rubber sheet in the thickness direction, on the sheet surface, 12). They are lined up at intervals of 5.5 mm).
Then, in accordance with ASTM D 2229, the steel cord was pulled out from each sample immediately after vulcanization, and the coverage of the rubber adhering to the steel cord was determined visually at 0 to 100% to determine the initial adhesiveness. It was used as an index. The larger the numerical value (coverage), the better the initial adhesiveness.

(2) Crack resistance Each sample was subjected to a constant stress fatigue test using a fatigue tester manufactured by Ueshima Seisakusho, and the number of times until it broke was measured. The evaluation is shown as an index when the number of breaks in Comparative Example 3 is 100. The larger the exponential value, the better the crack resistance.

(3) Workability
Using "RII-2CC" manufactured by Kodaira Seisakusho Co., Ltd., adjust the unvulcanized rubber composition to 1.0 kg and a rubber thickness of 3 mm, roll for 3 minutes, and then make a 5 cm wide sheet. A notch was made in the rubber on the roll, and the sheet was peeled off from the roll with only a spring, and the maximum value of the peeling force between the roll surface and the rubber was measured. The evaluation is shown as an index when the maximum value of the peeling force of Comparative Example 1 is 100. The larger the index value, the better the workability (tackiness).

* 1 Natural rubber: RSS # 3
* 2 Polyisoprene rubber: JSR, product name "IR2200"
* 3 Carbon black: HAF grade carbon black, manufactured by Asahi Carbon Co., Ltd., product name "Asahi # 70L"
* 4 Anti-aging agent: N-Phenyl-N'-(1,3-dimethylbutyl) -p-phenylenediamine, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Nocrack 6C"
* 5 Vulcanization accelerator: N, N'-dicyclohexyl-2-benzothiazolyl sulfenamide, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Noxeller DZ"
* 6 Cobalt fatty acid salt: manufactured by DIC Corporation, trade name "DICNAME NBC-II"
* 7 Bismaleimide compound A: 4,4'-diphenylmethane bismaleimide (BMI), manufactured by Daiwa Kasei Kogyo Co., Ltd., trade name "BMI-1000"
* 8 Bismaleimide compound B: m-phenylene bismaleimide (PBM), manufactured by Daiwa Kasei Kogyo Co., Ltd., trade name "BMI-3000"
* 9 Adhesive A: Alkylphenol adhesive (tack fire), manufactured by SI-Group, trade name "SP1068"
* 10 Adhesive-imparting agent B: Petroleum-based resin, manufactured by Mitsui Petrochemical Co., Ltd., trade name "Highlets G-100X"

From Table 1, it can be seen that the metal cord-rubber composite of the embodiment according to the present invention has a high degree of compatibility between the initial adhesiveness between the metal cord and the coated rubber and the crack resistance of the coated rubber.
On the other hand, in Comparative Example 1 and Comparative Example 2 in which the rubber composition for the coated rubber does not contain the bismaleimide compound, the initial adhesiveness is low, and in order to improve the initial adhesiveness, the rubber composition for the coated rubber is used. In Comparative Example 3 and Comparative Example 4 in which the cobalt fatty acid salt was blended, the crack resistance of the coated rubber was low, and both of them showed the initial adhesiveness between the metal cord and the coated rubber and the crack resistance of the coated rubber. It turns out that they are highly incompatible.
Further, from Examples 2 to 6, it can be seen that the workability is improved by adding the tackifier to the rubber composition for the coated rubber.

The metal cord-rubber composite of the present invention can be used for tires, industrial belts such as motion transmission belts and conveyor belts, rubber crawlers, hoses, rubber bearings for seismic isolation, and the like.

Claims (6)

A metal cord-rubber complex in which a metal cord is coated with a rubber composition.
The N atom on the surface of the metal cord is 2 atomic% or more and 60 atomic% or less, and the Cu / Zn ratio is 1 or more and 4 or less on a mass basis.
The rubber composition contains a rubber component, a filler, a bismaleimide compound, and a tackifier .
The tackifier is a phenolic resin and
A metal cord-rubber complex, wherein the content of cobalt in the rubber composition is in the range of 0 to 0.5 parts by mass with respect to 100 parts by mass of the rubber component. The metal cord-rubber composite according to claim 1 , wherein the content of cobalt in the rubber composition is in the range of 0 parts by mass or more and less than 0.1 parts by mass with respect to 100 parts by mass of the rubber component. The metal cord-rubber complex according to claim 1 or 2 , wherein the bismaleimide compound is 4,4'-diphenylmethane bismaleimide. A tire belt, wherein the metal cord-rubber complex according to any one of claims 1 to 3 is used. A carcass for a tire, wherein the metal cord-rubber complex according to any one of claims 1 to 3 is used. A tire using the metal cord-rubber complex according to any one of claims 1 to 3 .