JP2023077082A - Vulcanized rubber-metal complex and tire, hose, and crawler - Google Patents

Abstract

To provide a vulcanized rubber-metal complex that excels in low loss and adhesion between a vulcanized rubber and metal, and a tire that comprises the vulcanized rubber-metal complex and excels in low loss, a hose, and a crawler.SOLUTION: A vulcanized rubber-metal complex comprises a metal, and a vulcanized rubber that coats the metal. The vulcanized rubber is a vulcanized rubber of a rubber composition that comprises a rubber component, a filler, a thermosetting resin, and a methylene donor, with a content of a cobalt-containing compound being 0.01 pts.mass or less being relative to 100 pts.mass of the rubber component. The metal is a metal having a steel cord surface being coated with ternary plating of copper, zinc, and iron.SELECTED DRAWING: None

Description

This invention relates to vulcanized rubber-metal composites and tires, hoses, and crawlers.

Rubber products such as tires, belts and hoses are reinforced with reinforcing materials such as steel cords and organic fibers. These rubber products are required to strongly bond the rubber composition and the reinforcing material, especially the rubber composition and the steel cord.
As the steel cord coating rubber composition, 0.12 parts by mass or more of zinc bis(benzoate) and/or zinc bis(t-butylbenzoate) and cobalt element cobalt salt are added to 100 parts by mass of the rubber component. A rubber composition containing 0.03 to 0.30 parts by mass in terms of , a total of less than 0.5 parts by mass of a fatty acid having 16 to 22 carbon atoms and a fatty acid having 16 to 22 carbon atoms derived from a fatty acid cobalt salt known (see Patent Document 1).

In addition, as a rubber composition for coating steel cords, a rubber composition produced using a wet masterbatch obtained by mixing a slurry solution in which carbon black is dispersed and rubber latex, wherein the carbon black is , The dibutyl phthalate oil absorption (mL/100 g) measured based on JIS K 6217-4: 2008 is 60 mL/100 g or more and 90 mL/100 g or less, and the statistical thickness specific surface area measured based on JIS K6217-7: 2013 ( m ² /g) is 100 m ² /g or more and 150 m ² /g or less, and a rubber composition is known in which 35 parts by mass or more and 80 parts by mass or less of the carbon black is blended with 100 parts by mass of the rubber latex. (see Patent Document 2).

Also, a rubber cord composite comprising a steel cord made of a plated wire and a rubber coating the steel cord, wherein the plated wire has copper (Cu), zinc (Zn), A ternary plating layer made of cobalt (Co) is provided, and the ternary plating layer has a plating surface region with a depth of up to 15 nm from the surface, and the composition of the plating surface region is copper (Cu): 64 to 68 at%. , cobalt (Co): 0.5 to 7.0 at %, a steel cord-rubber composite is disclosed (see Patent Document 3).
Thus, it was known to complement the adhesion of the steel cord-rubber composite by plating the steel cord with cobalt.

US Pat. No. 5,300,001 discloses a steel cord with an iron particle-rich brass coating that allows the use of ternary alloy coatings even with cobalt-free compounds.

JP 2018-053244 A JP 2016-37547 A JP 2014-19974 A WO2020/156967

However, Patent Documents 1 to 3 do not discuss the vulcanized rubber-metal adhesion when the cobalt compound is excluded. In addition, the vulcanized rubber-metal composite described in Patent Document 4 has room for further improvement in terms of low loss properties.

In view of the above circumstances, the present invention provides a vulcanized rubber-metal composite with excellent low-loss properties and adhesion between vulcanized rubber and metal, and tires, hoses, and crawlers with excellent low-loss properties using the same. The purpose is to solve the purpose.

<1> A vulcanized rubber-metal composite comprising a metal and a vulcanized rubber covering the metal,
The vulcanized rubber contains a rubber component, a filler, a thermosetting resin, and a methylene donor, and the content of the cobalt-containing compound is 0.01 parts by mass or less per 100 parts by mass of the rubber component. A vulcanized rubber of a rubber composition,
The metal is a vulcanized rubber-metal composite in which the surface of the steel cord is coated with ternary plating of copper, zinc, and iron.

<2> The vulcanized rubber-metal composite according to <1>, wherein the amount of the iron in the coating is 1% by mass or more and less than 10% by mass of the total mass of the copper, the zinc and the iron.
<3> The vulcanized rubber-metal composite according to <1> or <2>, wherein the amount of phosphorus in the coating is more than 0 mg/m ² and not more than 4 mg/m ² .
<4> The vulcanized rubber-metal composite according to any one of <1> to <3>, wherein the steel cord is drawn with a diamond die.

<5><1> to <4>, wherein the rubber composition further contains at least one vulcanization accelerator selected from the group consisting of a thiuram-based vulcanization accelerator and a sulfenamide-based vulcanization accelerator. The vulcanized rubber-metal composite according to any one.
<6> The additive according to any one of <1> to <5>, wherein the rubber composition further contains 0.5 to 8 parts by mass of a reinforcing resin with respect to 100 parts by mass of the rubber component. Sulfur rubber-metal composite.

<7> The rubber composition contains carbon black, and the content of carbon black is 35 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the rubber component of the rubber composition <1> to <6 > The vulcanized rubber-metal composite according to any one of >.
<8> The vulcanization according to <7>, wherein the carbon black has a nitrogen adsorption specific surface area of 70 m ² /g or more and 90 m ² /g or less, and a dibutyl phthalate absorption amount of 50 mL/100 g or more and 110 mL/100 g or less. Rubber-metal composite.

<9> The additive according to any one of <1> to <8>, wherein the content of the cobalt-containing compound in the rubber composition is 0.00 parts by mass with respect to 100 parts by mass of the rubber component. Sulfur rubber-metal composite.
<10> Any one of <1> to <9>, wherein the content of the thermosetting resin in the rubber composition is more than 4 parts by mass and 20 parts by mass or less with respect to 100 parts by mass of the rubber component A vulcanized rubber-metal composite according to one.

<11> The vulcanized rubber-metal composite according to any one of <6> to <10>, wherein the reinforcing resin is syndiotactic-1,2-polybutadiene.
<12> Any one of <5> to <11>, wherein the mass ratio (thiuram-based vulcanization accelerator/thermosetting resin) in the rubber composition is 0.02 or more and less than 0.12 Vulcanized rubber-metal composite.
<13> The vulcanized rubber-metal composite according to <12>, wherein the thermosetting resin contains a phenolic resin.
<14> The vulcanized rubber-metal composite according to any one of <7> to <13>, wherein the filler contains the carbon black and silica.

<15> The vulcanized rubber-metal composite according to <14>, wherein the content of the silica in the rubber composition is more than 0 parts by mass and 15 parts by mass or less with respect to 100 parts by mass of the rubber component.
<16> The vulcanized rubber-metal composite according to any one of <5> to <15>, wherein the rubber composition contains N-cyclohexyl-2-benzothiazolylsulfenamide.

<17 The vulcanized rubber-metal composite according to any one of <13> to <16>, wherein the phenolic resin contains two or more phenolic resins and at least an alkylphenolic resin.

<18> The vulcanized rubber-metal composite according to <17>, wherein the phenol resin comprises an unmodified phenol-formaldehyde resin and an alkylphenol-formaldehyde resin.
<19> A tire comprising the vulcanized rubber-metal composite according to any one of <1> to <18>.
<20> The tire according to <19>, wherein the cobalt atom content is 1% by mass or less.
<21> A hose comprising the vulcanized rubber-metal composite according to any one of <1> to <18>.
<22> A crawler comprising the vulcanized rubber-metal composite according to any one of <1> to <18>.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a vulcanized rubber-metal composite having excellent low-loss property and adhesiveness between vulcanized rubber and metal, and a tire, hose, and crawler having excellent low-loss property using the same. .

It is Figure 3a of Patent Document 4.

The present invention will be described in detail below based on its embodiments. In the following description, the description of "A to B" indicating a numerical range represents a numerical range including A and B, which are end points, and "A or more and B or less" (when A < B), or "A hereinafter B or more” (when A>B).
Parts by mass and % by mass are synonymous with parts by weight and % by weight, respectively.

<Vulcanized rubber-metal composite>
The vulcanized rubber-metal composite of the present invention is a vulcanized rubber-metal composite comprising a metal and a vulcanized rubber covering the metal.
Here, the vulcanized rubber contains a rubber component, a filler, a thermosetting resin, and a methylene donor, and the content of the cobalt-containing compound is 0.01 parts by mass or less per 100 parts by mass of the rubber component. It is a vulcanized rubber of a rubber composition.
The vulcanized rubber is sometimes referred to as "the vulcanized rubber of the present invention".
The rubber composition from which the vulcanized rubber of the present invention is based is sometimes referred to as the "rubber composition of the present invention". The rubber composition is in an unvulcanized state, and the rubber component contained in the rubber composition is also in an unvulcanized state.
In the vulcanized rubber-metal composite of the present invention, the metal is a metal whose steel cord surface is coated with ternary plating of copper, zinc and iron (ternary plated metal).
The vulcanized rubber-metal composite in which the vulcanized rubber having the above structure and the metal having the above structure are bonded is the vulcanized rubber-metal composite of the present invention, or the vulcanized rubber of the present invention according to the first embodiment. - referred to as metal composites.

It is not clear why the vulcanized rubber-metal composite of the present invention has low loss and excellent adhesiveness between vulcanized rubber and metal, but the surface of the steel cord is coated with a copper-zinc-iron ternary plated metal. It has been found that the effect can be achieved by using the vulcanized rubber of the rubber composition of the present invention having the above structure as the rubber.

The vulcanized rubber-metal composite of the present invention is not particularly limited as long as it satisfies the requirements of the vulcanized rubber-metal composite of the present invention according to the first embodiment. 3. It may be a vulcanized rubber-metal composite according to the fourth embodiment.

The vulcanized rubber-metal composite of the present invention according to the second embodiment is
A vulcanized rubber-metal composite comprising a metal and a vulcanized rubber covering the metal,
The vulcanized rubber contains a rubber component, a filler, a thermosetting resin, more than 4 parts by mass and 20 parts by mass or less per 100 parts by mass of the rubber component, a methylene donor, and a vulcanization accelerator. A vulcanized rubber of a rubber composition having a reinforcing resin content of 2 parts by mass or more and 8 parts by mass or less and a cobalt compound content of 0.01 part by mass or less per 100 parts by mass of the rubber component. can be,
The metal is a metal whose steel cord surface is coated with ternary plating of copper, zinc, and iron.
The vulcanized rubber-metal composite of the present invention according to the second embodiment has excellent low-loss properties and adhesion between the vulcanized rubber and metal, and when used for tire production, the obtained tire is , excellent handling stability, fuel efficiency and crack growth resistance.

The vulcanized rubber-metal composite of the present invention according to the third embodiment is
A vulcanized rubber-metal composite comprising a metal and a vulcanized rubber covering the metal,
The vulcanized rubber contains a rubber component, a filler, a thermosetting resin, a methylene donor, a thiuram-based vulcanization accelerator, and a sulfenamide-based vulcanization accelerator, and the rubber component is 100 mass. A vulcanized rubber of a rubber composition having a cobalt compound content of 0.01 parts by mass or less per part,
The metal is a metal whose steel cord surface is coated with ternary plating of copper, zinc, and iron.
The vulcanized rubber-metal composite of the present invention according to the third embodiment has excellent low-loss properties and adhesion between the vulcanized rubber and metal, and when used for tire production, the resulting tire is , Excellent crack growth resistance and fuel efficiency.

The vulcanized rubber-metal composite of the present invention according to the fourth embodiment is
A vulcanized rubber-metal composite comprising a metal and a vulcanized rubber covering the metal,
The vulcanized rubber contains a rubber component, a filler, a phenolic resin, and a methylene donor, and further has a cobalt compound content of 0.01 parts by mass or less per 100 parts by mass of the rubber component. A vulcanized rubber of a rubber composition,
The metal is a metal whose steel cord surface is coated with ternary plating of copper, zinc, and iron.
The vulcanized rubber-metal composite of the present invention according to the fourth embodiment has excellent low-loss property and adhesion between vulcanized rubber and metal, and further has excellent wet heat adhesion between vulcanized rubber and steel cord. .

The rubber composition and metal of the present invention are described below.
The rubber composition constituting the vulcanized rubber of the vulcanized rubber-metal composite of the present invention according to the second embodiment is referred to as the "rubber composition according to the second embodiment"; The rubber composition constituting the vulcanized rubber of the vulcanized rubber-metal composite of the present invention is the “rubber composition according to the third embodiment”; the vulcanized rubber-metal composite of the present invention according to the fourth embodiment The rubber composition constituting the vulcanized rubber of the body may be referred to as "the rubber composition according to the fourth embodiment".

[Rubber composition]
The rubber composition of the present invention contains a rubber component, a filler, a thermosetting resin, and a methylene donor, and the content of the cobalt-containing compound is 0.01 parts by mass or less per 100 parts by mass of the rubber component. is.
The rubber composition of the present invention may further contain a vulcanization accelerator, stearic acid, zinc white and the like.

(rubber component)
A diene rubber is usually used as the rubber component.
Examples of diene rubbers include isoprene rubbers, polybutadiene rubbers (BR), styrene-butadiene copolymer rubbers (SBR), and modified rubbers thereof. Moreover, the rubber component may contain a non-diene rubber as long as it does not impair the effects of the present invention.
Only one kind of rubber component may be used, or two or more kinds may be mixed and used.
Among the above, the rubber component preferably contains an isoprene-based rubber from the viewpoint of further improving the low loss property of the vulcanized rubber-metal composite and the vulcanized rubber-metal adhesiveness.

Isoprene rubbers include natural rubber (NR), polyisoprene rubber (IR), butadiene-isoprene copolymer rubber (BIR), styrene-isoprene copolymer rubber (SIR), styrene-butadiene-isoprene copolymer rubber. (SBIR), etc., and modified rubbers thereof. Only one type of isoprene-based rubber may be used, or two or more types may be mixed and used.
Among the above, from the viewpoint of further improving the low loss property of the vulcanized rubber-metal composite and the vulcanized rubber-metal adhesion, the isoprene-based rubber is one selected from the group consisting of natural rubber and polyisoprene rubber. The above are preferable, and natural rubber is more preferable. As natural rubber, epoxidized natural rubber, deproteinized natural rubber and other modified natural rubbers may be used.

Examples of natural rubber include natural rubber grades such as RSS#1, RSS#3, TSR20, and SIR20.
As the epoxidized natural rubber, those having a degree of epoxidation of 10 to 60 mol % are preferable, and ENR25 and ENR50 manufactured by Kumpuran Guthrie can be exemplified.
As the deproteinized natural rubber, deproteinized natural rubber having a total nitrogen content of 0.3% by mass or less is preferable.
Other modified natural rubbers contain polar groups obtained by reacting natural rubber with 4-vinylpyridine, N,N-dialkylaminoethyl acrylate such as N,N-diethylaminoethyl acrylate, 2-hydroxy acrylate, etc. in advance. A modified natural rubber that can be used is used as necessary.

The content of isoprene-based rubber in the rubber component is preferably greater than 50% by mass, preferably 70% by mass or more, more preferably 90% by mass or more, and may be 100% by mass. .
In particular, in the rubber composition according to the third embodiment, 55% by mass of natural rubber is used from the viewpoint of achieving both low loss of vulcanized rubber and high wet heat adhesion between steel cord and vulcanized rubber. The content is preferably 65% by mass or more, more preferably 75% by mass or more, and still more preferably 75% by mass or more. The upper limit of the ratio of natural rubber in the rubber component is 100% by mass.

(filler)
The rubber composition of the present invention contains a filler.
The inclusion of a filler in the rubber composition can improve the mechanical strength of the vulcanized rubber.
The filler is preferably a reinforcing filler that reinforces the rubber composition.
Examples of reinforcing fillers include carbon black; metal oxides such as silica, alumina, titania and zirconia; metal carbonates such as magnesium carbonate and calcium carbonate; and aluminum hydroxide.
Only one filler may be used, or two or more fillers may be used.

[Carbon black]
From the viewpoint of improving the reinforcing properties of the vulcanized rubber of the present invention and obtaining a vulcanized rubber-metal composite having excellent adhesion between the metal and the vulcanized rubber, the filler preferably contains carbon black.
The type of carbon black is not particularly limited and can be appropriately selected according to the purpose. For example, carbon blacks of FEF, SRF, HAF, ISAF, and SAF grades are preferred, HAF, ISAF, and SAF grades are more preferred, and HAF grades are even more preferred. Only one type of carbon black may be used, or two or more types may be used.

By using carbon black with a low dibutyl phthalate absorption (DBP absorption), that is, a carbon black with a low structure, the low loss property of the vulcanized rubber can be improved. In addition, from the viewpoint of improving tire durability, carbon black has a nitrogen adsorption specific surface area (N ₂ SA) of 70 m ² /g or more and 90 m ² /g or less, and a dibutyl phthalate absorption amount (DBP absorption amount) of It is preferably 50 mL/100 g or more and 110 mL/100 g or less.

From the viewpoint of further improving the low loss property and durability of vulcanized rubber, the nitrogen adsorption specific surface area of carbon black is more preferably 70 m ² /g or more and 85 m ² /g or less, and more preferably 73 m ² /g or more and 83 m ² /g or less is more preferable.
Similarly, the dibutyl phthalate absorption amount of carbon black is more preferably 65 mL/100 g or more and 110 mL/100 g or less, more preferably 90 mL/100 g or more and 110 mL/ It is preferably 100 g or less.
In addition, since the adhesion durability of the tire is improved by suppressing heat generation (loss), the grade of carbon black is preferably HAF grade (HAF, HAF-LS), which is a grade with low heat generation (low loss property). .
The carbon black may be used singly or in combination of two or more kinds selected from those mentioned above.

The N ₂ SA of carbon black is determined by Method A of JIS K 6217-2:2001 (Determination of specific surface area--nitrogen adsorption method--single point method). The DBP absorption of carbon black is measured by the method described in JIS K 6217-4:2001 "Determination of DBP absorption", and is indicated by the volume ml of dibutyl phthalate (DBP) absorbed per 100 g of carbon black. be.

The content of the filler in the rubber composition is preferably 30 to 60 parts by mass with respect to 100 parts by mass of the rubber component. part of carbon black is preferably contained.
The rubber composition contains 30 to 60 parts by mass of a filler with respect to 100 parts by mass of the rubber component, thereby improving the reinforcing properties of the vulcanized rubber of the present invention and improving the adhesion between the metal and the vulcanized rubber. An excellent vulcanized rubber-metal composite can be easily obtained.

In the rubber composition according to the second embodiment, the content of carbon black is preferably 30 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the rubber component, and 35 parts by mass or more and 60 parts by mass. It is more preferably 35 parts by mass or more and 50 parts by mass or less.

In the rubber composition according to the third embodiment, the content of carbon black is preferably 30 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the rubber component, and 30 parts by mass or more and 70 parts by mass. It is more preferably 35 parts by mass or more and 60 parts by mass or less, and particularly preferably 35 parts by mass or more and 50 parts by mass or less. By reducing the carbon black content, it is possible to improve the low-loss properties of the vulcanized rubber.

In the rubber composition according to the fourth embodiment, the content of carbon black is 35 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the rubber component from the viewpoint of further improving the durability of the tire. , more preferably 37 parts by mass or more and 50 parts by mass or less, and even more preferably 37 parts by mass or more and 48 parts by mass or less.

(silica)
The filler may contain silica.
In particular, the rubber composition according to the fourth embodiment preferably contains silica as a filler. Since the rubber composition according to the fourth embodiment contains silica, the reaction of the phenolic resin is promoted, and the low loss property of the vulcanized rubber obtained from the rubber composition and the wet heat adhesion of the vulcanized rubber to steel cords are improved. improve more.

The type of silica is not particularly limited, and includes wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), colloidal silica, and the like. Silica may be used individually by 1 type, and may use 2 or more types together.

The cetyltrimethylammonium bromide (CTAB) specific surface area of silica is preferably 80 m ² /g or more and 250 m ² /g or less, more preferably 100 m ² /g or more and 200 m ² /g or less, and 120 m ² /g More preferably, it is at least 180 m ² /g or less.
When the CTAB specific surface area of silica is in the above range, the low loss of vulcanized rubber and the adhesion of vulcanized rubber to metal (especially steel cord) (vulcanized rubber according to the fourth embodiment-metal composite In this case, wet heat adhesion) can be further improved.
The CTAB specific surface area of silica can be measured by a method conforming to the method of ASTM-D3765-80.
The rubber composition of the present invention may further contain a silane coupling agent in order to improve the dispersibility of silica and improve the reinforcing properties and low heat build-up of the vulcanized rubber.

From the viewpoint of further improving the low-loss properties of the vulcanized rubber and the wet heat adhesion of the vulcanized rubber to metals (especially steel cords), the content of silica in the rubber composition is, per 100 parts by mass of the rubber component, It is preferably more than 0 parts by mass and 15 parts by mass or less. When the content of silica is more than 0 parts by mass with respect to 100 parts by mass of the rubber component, the reaction of the thermosetting resin (especially phenolic resin) is promoted, and when it is 15 parts by mass or less, the rubber composition Suppresses the viscosity of The content of silica in the rubber composition is more preferably 0.5 parts by mass or more and 12 parts by mass or less, and more preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the rubber component. is more preferred. The content of silica in the rubber composition may be less than 5 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of processability of the rubber composition.

(Thermosetting resin)
The rubber composition of the present invention contains a thermoplastic resin.
By containing a thermoplastic resin in the rubber composition, the vulcanized rubber obtained from the rubber composition has excellent low-loss property and excellent adhesiveness (especially wet heat adhesiveness) to metals of the vulcanized rubber.
The thermosetting resin is not particularly limited as long as it contains phenol, resorcin, etc. as a structural unit, but a phenol resin is preferably used.

The phenol resin is not particularly limited and can be appropriately selected according to the required performance. Examples thereof include those produced by condensation reaction of phenols such as phenol, cresol, resorcinol and tert-butylphenol or mixtures thereof with formaldehyde in the presence of an acid catalyst such as hydrochloric acid and oxalic acid.
The phenolic resin may be unmodified or modified.
Examples of unmodified phenol resins include phenol resins and phenol-formaldehyde resins.
The modified phenol resin has a structure obtained by modifying an unmodified phenol resin with an oil such as rosin oil, tall oil, cashew oil, linoleic acid, oleic acid, or linolenic acid, and a hydrocarbon group is added to the phenol skeleton of the phenol resin. (for example, an alkyl group, etc.).
In the present invention, a phenol resin having an alkyl group on the phenol skeleton of the phenol resin is referred to as an alkylphenol resin. The number of alkyl groups (number of bonds to the phenol skeleton) and the number of carbon atoms in the alkyl group of the alkylphenol resin are not particularly limited, but the number of alkyl groups is usually 1 to 3, and the number of carbon atoms per alkyl group is 1. ~15 is preferred, and 5-10 is preferred. The alkyl group may be linear, branched, or cyclic, preferably branched.
The rubber composition of the present invention can contain one type of phenol resin alone, or can contain a mixture of two or more types.

In the rubber composition according to the fourth embodiment, from the viewpoint of further improving the low loss property of the vulcanized rubber obtained from the rubber composition, the phenol resin contains two or more phenol resins, and at least an alkylphenol resin is preferably included. That is, as the containing form, (1) one type of alkylphenol resin is included, and one or more types of alkylphenol resins different from the alkylphenol resin (other alkylphenol resins) are included, and (2) one type of alkylphenol resin is included. , a form containing one or more phenolic resins other than alkylphenol resins (other phenolic resins), (3) a form containing one alkylphenol resin, one or more other alkylphenol resins, and one or more other phenolic resins, etc. is mentioned.
Among them, from the viewpoint of further improving the low loss property of the vulcanized rubber obtained from the rubber composition according to the fourth embodiment, (2) a form containing one alkylphenol resin and one or more other phenol resins is preferred, and a form containing one type of alkylphenol resin and one or more types of unmodified phenolic resin is more preferred.
Specifically, it is preferable to use a phenol-formaldehyde resin and an alkylphenol-formaldehyde resin together.

The content of the thermosetting resin in the rubber composition is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the rubber component, more than 4 parts by mass and preferably 20 parts by mass or less, It is more preferably more than 4 parts by mass and 18 parts by mass or less, more preferably more than 4 parts by mass and 16 parts by mass or less, and particularly preferably more than 4 parts by mass and 14 parts by mass or less. .
If the content of the thermosetting resin according to the present invention exceeds 4 parts by mass with respect to 100 parts by mass of the rubber component, sufficient adhesiveness (particularly, adhesiveness after wet heat deterioration) can be obtained.
If the amount of the thermosetting resin is 20 parts by mass or less with respect to 100 parts by mass of the rubber component, the adhesion reaction during vulcanization does not proceed excessively, so the adhesion (especially, the adhesion after wet heat deterioration It is possible to prevent the deterioration of

In particular, in the rubber composition according to the fourth embodiment, the content of the phenolic resin in the rubber composition (the total amount of phenolic resin) is 100 parts by mass of the rubber component from the viewpoint of improving the low-loss property of the vulcanized rubber. is preferably 1 to 20 parts by mass, more preferably 3 to 15 parts by mass.
The content of the alkylphenol resin in the rubber composition according to the fourth embodiment is 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of improving the low loss property of the vulcanized rubber. is preferable, 0.3 to 5 parts by mass is more preferable, and 0.5 to 3 parts by mass is even more preferable.
In addition, when an unmodified phenol resin and an alkyl phenol resin are used in combination, the total content of both in the rubber composition is 1 to 20 parts by mass with respect to 100 parts by mass of the rubber component, and Modified phenol resin: Alkyl phenol resin is preferably 2:1 to 10:1 on a mass basis

The softening point of the thermosetting resin according to the present invention is preferably 150° C. or lower, more preferably in the range of 80° C. or higher and 150° C. or lower, and further preferably in the range of 80° C. or higher and 140° C. or lower. It is preferably 90° C. or higher and 140° C. or lower, particularly preferably.
Since the softening point of the thermosetting resin is 150 ° C. or less, when the thermoplastic resin is blended into the rubber composition during kneading of the rubber composition, the decrease in dispersion of the thermoplastic resin in the rubber composition is suppressed. and does not easily impair the adhesion between vulcanized rubber and metal. Blocking is suppressed when the softening point of the thermoplastic resin is 80° C. or higher.

(methylene donor)
The rubber composition of the present invention contains a methylene donor.
As a methylene donor, hexamethoxymethylmelamine (HMMM), modified etherified methylolmelamine resin, hexamethylenetetramine (HMT), pentakis(methoxymethyl)methylolmelamine, tetrakis(methoxymethyl)dimethylolmelamine and the like are commonly used in the rubber industry. You can mention what is used.
Among them, hexamethoxymethylmelamine alone, modified etherified methylolmelamine resin alone, or a mixture containing them as main components is preferred. These methylene donors can be used alone or in combination of two or more.

The content of the methylene donor in the rubber composition is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, and 1 part by mass or more with respect to 100 parts by mass of the rubber component. It is more preferably 8 parts by mass or less, and particularly preferably 1 part by mass or more and 6 parts by mass or less. If the content is 0.5 parts by mass or more with respect to 100 parts by mass of the rubber component, the thermosetting resin can be cured, and if it is 10 parts by mass or less, the vulcanization speed of the rubber composition is too fast. You can prevent it from happening.

(Reinforcing resin)
The rubber composition of the present invention may contain a reinforcing resin.
In particular, the rubber composition according to the second embodiment preferably contains a reinforcing resin.
The reinforcing resin refers to a resin composite material in which a reinforcing resin or a reinforcing crystal is mixed with and dispersed in a thermoplastic resin. Examples of the reinforcing resin include syndiotactic-1,2-polybutadiene and highly crystalline resins made from acetal copolymers. Examples of the resin composite material include potassium titanate fibers (for example, Otsuka A resin composite material in which TISMO (trade name, manufactured by Kagaku Co., Ltd.) is blended and dispersed in a thermoplastic resin is exemplified.
Among these reinforcing resins, syndiotactic-1,2-polybutadiene (hereinafter sometimes abbreviated as SPB) is preferred. This is because it melts at the masterbatch kneading temperature of the rubber composition and satisfactorily disperses the rubber composition.
The content of the reinforcing resin in the rubber composition is preferably 0.5 to 8 parts by mass, more preferably 2.5 to 7.5 parts by mass, with respect to 100 parts by mass of the rubber component. preferable. The content of the reinforcing resin in the rubber composition is more preferably 3 parts by mass or more, more preferably 7.0 parts by mass or less, and 6.5 parts by mass with respect to 100 parts by mass of the rubber component. It is more preferably not more than parts by mass.

[Syndiotactic-1,2-polybutadiene (SPB)]
Syndiotactic-1,2-polybutadiene (SPB) is a polybutadiene-based thermoplastic elastomer, and the 1,2 bond content in SPB is preferably 88% by mass or more, more preferably 90% by mass or more. It is preferably 92% by mass or more, more preferably 93% by mass or more, and particularly preferably 93% by mass or more.
The melting point of SPB is preferably 130° C. or lower from the viewpoint of melting at the masterbatch kneading temperature of the rubber composition, and preferably 65° C. or higher from the viewpoint of blocking prevention.
The melting point of SPB is more preferably 80° C. or higher and 130° C. or lower, and still more preferably 100° C. or higher and 130° C. or lower.
Commercially available SPBs can also be used. content: 93 wt%, melting point: 105°C), trade name “RB820” (1,2 bond content: 92 wt%, melting point: 95°C), trade name “RB810” (1,2 bond content: 90 wt%, Melting point: 71°C), trade name “AT400” (1,2 bond content: 94% by mass, melting point: 126°C), trade name “AT300” (1,2 bond content: 93% by mass, melting point: 105°C), etc. is mentioned.

When polybutadiene rubber is contained in the rubber component of the rubber composition, a polybutadiene rubber-syndiotactic-1,2-polybutadiene composite (BR-SPB composite) in which SPB is dispersed in polybutadiene rubber is used. good too. Commercially available BR-SPB complexes may be used, for example, VCR412 (SPB crystal content: 12.0% by mass, matrix polymer cis content: 98% by mass), VCR617 manufactured by Ube Industries, Ltd. (SPB crystal content: 12.0 mass%, matrix polymer cis content: 98 mass%), VCR450 (SPB crystal content: 3.8 mass%, matrix polymer cis content: 98 mass%), VCR800 (SPB crystal content: 5.3% by mass, cis content of matrix polymer: 98% by mass), and the like.

(Vulcanization accelerator)
The rubber composition of the present invention preferably contains a vulcanization accelerator.
Examples of vulcanization accelerators include thiazole-based vulcanization accelerators and thiuram-based vulcanization accelerators described on pages 412-413 of Rubber Industry Handbook <4th Edition> (January 20, 1994, published by the Japan Rubber Association). Examples include vulcanization accelerators, sulfenamide vulcanization accelerators, and guanidine vulcanization accelerators.
Among the above, from the viewpoint of improving the low-loss property of the vulcanized rubber, the rubber composition contains at least one vulcanization accelerator selected from the group consisting of thiuram-based vulcanization accelerators and sulfenamide-based vulcanization accelerators. It preferably contains an agent.
In particular, the rubber composition according to the second embodiment and the rubber composition according to the fourth embodiment preferably contain a sulfenamide-based vulcanization accelerator, and the rubber composition according to the third embodiment , a thiuram-based vulcanization accelerator and a sulfenamide-based vulcanization accelerator.

[Thiuram-based vulcanization accelerator]
Thiuram-based vulcanization accelerators include tetrakis(2-ethylhexyl)thiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide, tetrabenzylthiuram disulfide, and the like. is mentioned.
Commercially available thiuram-based vulcanization accelerators may be used, and examples of tetrakis(2-ethylhexyl) thiuram disulfide include Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Noxeler TOT"; examples of tetraethylthiuram disulfide include , Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Noccellar TET"; Tetramethylthiuram disulfide, for example, Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Noccellar TT"; Tetrabutyl thiuram disulfide, for example , Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Nocceler TBT"; Tetramethylthiuram monosulfide, for example, Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Nocceler TS"; dipentamethylene thiuram tetrasulfide Examples thereof include Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Nocceler TRA"; and Kawaguchi Chemical Co., Ltd. trade name, "Accel TBZT" as tetrabenzylthiuram disulfide.

[Sulfenamide vulcanization accelerator]
Sulfenamide vulcanization accelerators include N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide, N-tert-butyl-2- benzothiazolylsulfenamide (BBS), N-oxydiethylene-2-benzothiazolylsulfenamide, N-methyl-2-benzothiazolylsulfenamide, N-ethyl-2-benzothiazolylsulfenamide, N-propyl-2-benzothiazolylsulfenamide, N-butyl-2-benzothiazolylsulfenamide, N-pentyl-2-benzothiazolylsulfenamide, N-hexyl-2-benzothiazolylsulfenamide amide, N-heptyl-2-benzothiazolylsulfenamide, N-octyl-2-benzothiazolylsulfenamide, N-2-ethylhexyl-2-benzothiazolylsulfenamide, N-decyl-2-benzo Thiazolylsulfenamide, N-dodecyl-2-benzothiazolylsulfenamide, N-stearyl-2-benzothiazolylsulfenamide, N,N-dimethyl-2-benzothiazolylsulfenamide, N,N -diethyl-2-benzothiazolylsulfenamide, N,N-dipropyl-2-benzothiazolylsulfenamide, N,N-dibutyl-2-benzothiazolylsulfenamide, N,N-dipentyl-2- benzothiazolylsulfenamide, N,N-dihexyl-2-benzothiazolylsulfenamide, N,N-diheptyl-2-benzothiazolylsulfenamide, N,N-dioctyl-2-benzothiazolylsulfenamide amide, N,N-di-2-ethylhexylbenzothiazolylsulfenamide, N,N-didecyl-2-benzothiazolylsulfenamide, N,N-didodecyl-2-benzothiazolylsulfenamide, N, and N-distearyl-2-benzothiazolylsulfenamide.
Among these, the rubber composition more preferably contains at least N-cyclohexyl-2-benzothiazolylsulfenamide.

Commercially available sulfenamide-based vulcanization accelerators may be used, and as N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), for example, Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Noxeller CZ"; N-tert-butyl-2-benzothiazolylsulfenamide (BBS), for example, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Noxcellar NS"; N-oxydiethylene-2-benzothia Examples of solylsulfenamide include those manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. under the trade name of "Noccellar MSA" and those manufactured by Kawaguchi Kagaku Kogyo Co., Ltd. under the trade name of "Accel NS".

[Thiazole-based vulcanization accelerator, guanidine-based vulcanization accelerator, etc.]
Thiazole-based vulcanization accelerators include, for example, 2-mercaptobenzothiazole (MBT) and dibenzothiazyl disulfide (MBTS).
Guanidine vulcanization accelerators include, for example, diphenylguanidine (DPG), 1,3-di-o-tolylguanidine (DOTG), 1-o-tolylbiguanide (OTBG) and the like.
In addition, vulcanization accelerators such as thiourea-based vulcanization accelerators such as trimethylthiourea (TMU), N,N'-diethylthiourea (DEU) and N,N'-diphenylthiourea may be used.

The amount of the vulcanization accelerator used is not particularly limited, but is preferably in the range of 0.5 parts by mass to 10 parts by mass, and 0.5 parts by mass to 8 parts by mass, based on 100 parts by mass of the rubber component. is more preferable, the range of 0.5 parts by mass or more and 7 parts by mass or less is more preferable, and the range of 0.5 parts by mass or more and 6 parts by mass or less is particularly preferable.
In particular, in the rubber composition according to the fourth embodiment, from the viewpoint of improving the low heat build-up of the vulcanized rubber and the wet heat adhesion of the vulcanized rubber to the steel cord, the rubber composition contains a vulcanization accelerator. The amount is preferably 0.5 parts by mass or more and 3.0 parts by mass or less, more preferably 0.8 parts by mass or more and 2.0 parts by mass or less with respect to 100 parts by mass of the rubber component.

In addition, in the rubber composition according to the third embodiment, the content of the thiuram-based vulcanization accelerator is preferably 0.1 parts by mass or more and 0.2 parts by mass or more with respect to 100 parts by mass of the rubber component. , 5 parts by mass or less, 3 parts by mass or less, 2 parts by mass or less, 1 part by mass or less, and less than 0.7 parts by mass.
The content of the sulfenamide-based vulcanization accelerator in the rubber composition according to the third embodiment is 0.3 parts by mass or more and 8 parts by mass with respect to 100 parts by mass of the rubber component with respect to 100 parts by mass of the rubber component. The range of 0.4 parts by mass or more and 7 parts by mass or less is more preferable, the range of 0.4 parts by mass or more and 6 parts by mass or less is even more preferable, and the range of 0.4 parts by mass or more and 5 parts by mass or less is preferable. Ranges are particularly preferred.
Furthermore, it preferably contains 0.1 parts by mass or less of a vulcanization accelerator N,N-dicyclohexyl-2-benzothiazolylsulfenamide, and more preferably does not contain it.
The mass ratio (sulfenamide vulcanization accelerator/thiuram vulcanization accelerator) is preferably greater than 1 and 10 or less, more preferably 1.1 to 8, still more preferably 1.2 to 6, and 1.2 to 5 is even more preferred.

Furthermore, in the rubber composition according to the third embodiment, the mass ratio (thiuram-based vulcanization accelerator/thermosetting resin) in the rubber composition is preferably 0.02 or more and less than 0.12. This is because the curing reaction of the thermosetting resin can be accelerated and the crack propagation resistance can be improved. From this point of view, if the mass ratio is 0.02 or more, it is preferable because the curing reaction of the thermosetting resin is accelerated. It is preferable because the number of sulfide crosslinks does not increase excessively. The mass ratio (thiuram-based vulcanization accelerator/thermosetting resin) is more preferably 0.03 or more and 0.10 or less, and even more preferably 0.05 or more and 0.08 or less.
The rubber composition according to the third embodiment preferably contains N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) as a sulfenamide vulcanization accelerator.
The content of N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) in the rubber composition according to the third embodiment is 0.1 parts by mass or more and 8.0 parts by mass with respect to 100 parts by mass of the rubber component. 0.2 parts by mass or more and 6.0 parts by mass or less is more preferable, 0.3 parts by mass or more and 5.0 parts by mass or less is even more preferable, and 0.4 parts by mass or more and 4.0 parts by mass or less is particularly preferred.

(Cobalt-containing compound)
The content of the cobalt-containing compound in the rubber composition of the present invention is 0.01 parts by mass or less per 100 parts by mass of the rubber component. This means that the rubber composition of the present invention is substantially free of cobalt-containing compounds.
Examples of cobalt-containing compounds include organic acid cobalt salts and cobalt metal complexes.
Organic acid cobalt salts include, for example, cobalt naphthenate, cobalt stearate, cobalt neodecanoate, cobalt rosinate, cobalt versatate, cobalt tallate, cobalt oleate, cobalt linoleate, cobalt linolenate, cobalt palmitate, and the like. can be mentioned. Cobalt metal complexes include, for example, cobalt acetylacetonate.
It is preferable that the rubber composition of the present invention does not contain a cobalt-containing compound, that is, the content of the cobalt-containing compound in the rubber composition is 0.00 parts by mass with respect to 100 parts by mass of the rubber component.

In the past, a cobalt-containing compound was used to obtain the effect of adhesion between vulcanized rubber and metal. Even without it, the adhesion between vulcanized rubber and metal is excellent, and the loss is also excellent. Moreover, since the rubber composition does not contain a cobalt-containing compound, it is possible to suppress metal corrosion and reduce the burden on the environment.

(Various components)
The rubber composition of the present invention may optionally contain various chemicals commonly used in the rubber industry, such as vulcanizing agents, vulcanization retarders, process oils, anti-aging agents, etc., as long as the effects of the present invention are not impaired. Zinc oxide, stearic acid and the like may be included.

[Vulcanizing agent]
Sulfur etc. are mentioned as a vulcanizing agent. Sulfur components include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur. Insoluble sulfur and powdered sulfur are generally preferred.
The amount of the vulcanizing agent to be used is preferably 1 part by mass or more and 12 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, and still more preferably 1.0 part by mass in terms of sulfur content relative to 100 parts by mass of the rubber component. 8.0 parts by mass or less. When the amount is 1 part by mass or more, the breaking strength, wear resistance, and fuel efficiency of the vulcanized rubber are less likely to be impaired, and when the amount is 12 parts by mass or less, the rubber elasticity of the vulcanized rubber is less likely to be impaired.

[Anti-aging agent]
Examples of anti-aging agents include those described on pages 436 to 443 of "Rubber Industry Handbook <4th Edition>" edited by the Japan Rubber Association. Specifically, for example, amine-based, quinoline-based, quinone-based, phenol-based, imidazole-based compounds, and anti-aging agents such as metal carbamates can be used.

Examples of the amine anti-aging agent include phenylenediamine anti-aging agents having a phenylenediamine skeleton (--NH--Ph--NH--).
Specifically, for example, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (sometimes referred to as 6PPD or 6C), N-isopropyl-N'-phenyl-p- Phenylenediamine (sometimes referred to as 3C), N,N'-diphenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl- p-phenylenediamine, N,N'-bis(1-methylheptyl)-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N'-dicyclohexyl- p-phenylenediamine, N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N-4-methyl-2-pentyl-N'-phenyl-p-phenylenediamine, N,N '-diaryl-p-phenylenediamine, hindered diaryl-p-phenylenediamine, phenylhexyl-p-phenylenediamine, phenyloctyl-p-phenylenediamine and the like.

Among them, it is preferable to have no double bond other than the phenylenediamine moiety (-NH-Ph-NH-). Specifically, the following formula (1) (R ¹ -NH-Ph-NH-R ² ) An amine anti-aging agent represented by is preferred.

In formula (1) above, R ¹ and R ² are each independently a monovalent saturated hydrocarbon group.
R ¹ and R ² may be the same or different, but are preferably the same from the viewpoint of synthesis.

The monovalent saturated hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, and particularly preferably 6 and 7 carbon atoms. When the number of carbon atoms in the saturated hydrocarbon group is 20 or less, the number of moles per unit mass increases, so that the anti-aging effect increases and the ozone resistance of the vulcanized rubber of the rubber composition improves.
From the viewpoint of further improving the ozone resistance of the vulcanized rubber of the rubber composition, R ¹ and R ² in the above formula (1) each independently represent a linear or cyclic monovalent monovalent compound having 1 to 20 carbon atoms. A saturated hydrocarbon group is preferred.

Examples of the monovalent saturated hydrocarbon group include an alkyl group and a cycloalkyl group. The alkyl group may be linear or branched, and the cycloalkyl group may further include an alkyl group as a substituent. etc. may be combined.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, 1,2-dimethylbutyl group, 1,3- dimethylbutyl group, 2,3-dimethylbutyl group, n-pentyl group, isopentyl group, neopentyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1,2 -dimethylpentyl group, 1,3-dimethylpentyl group, 1,4-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,4-dimethylpentyl group, n-hexyl group, Examples include 1-methylhexyl group, 2-methylhexyl group, various octyl groups, various decyl groups, various dodecyl groups, etc. Among these, 1,4-dimethylpentyl group is preferred.
Examples of the cycloalkyl group include a cyclopentyl group, a methylcyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, etc. Among these, a cyclohexyl group is preferred.

The amine anti-aging agent represented by formula (1) may be carried on any carrier. For example, the amine anti-aging agent represented by formula (1) may be carried on inorganic fillers such as silica and calcium carbonate.
Moreover, the amine anti-aging agent represented by Formula (1) may constitute a masterbatch together with the rubber component. Here, the rubber component used in forming the masterbatch is not particularly limited, and may be diene rubber such as natural rubber (NR), ethylene-propylene-diene rubber (EPDM), or the like. .
Moreover, the amine anti-aging agent represented by Formula (1) may be a salt with an organic acid. Here, the organic acid used for forming the salt is not particularly limited, but stearic acid and the like can be mentioned.

A quinoline anti-aging agent can also be suitably used. ), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (sometimes referred to as AW), and the like.
Alternatively, a high temperature condensate of diphenylamine and acetone may be used.
The above anti-aging agents may be used alone or in combination of two or more.
Among the above, the anti-aging agent preferably contains one or more selected from the group consisting of an amine-based anti-aging agent and a quinoline-based anti-aging agent, and more preferably includes at least an amine-based anti-aging agent.

The amount of anti-aging agent used is preferably 0.1 to 8.0 parts by mass, more preferably 0.1 to 6.0 parts by mass, and 0.3 to 5.0 parts by mass with respect to 100 parts by mass of the rubber component. Part is particularly preferred.

(Preparation of rubber composition)
The rubber composition of the present invention is obtained by kneading the various components and additives described above using a kneader such as an open kneader such as a roll or a closed kneader such as a Banbury mixer.
The rubber composition of the present invention is, for example, in the first stage of kneading (masterbatch kneading stage), a rubber component, a filler, a thermosetting resin, a reinforcing resin, and other masterbatch compounding agents. After kneading, in the final stage of kneading, the vulcanizing agent, vulcanization accelerator, methylene donor and, if necessary, other compounding ingredients are mixed.

〔metal〕
The metal contained in the rubber-metal composite of the present invention is a metal whose steel cord surface is coated with three-dimensional plating of copper, zinc, and iron (three-dimensionally plated metal).
Steel cords may be steel monofilaments or multifilaments (twisted cords or aligned bundled cords), and are not limited in shape. When the steel cord is a twisted cord, the twisted structure is not particularly limited, and examples thereof include a single twisted structure, a double twisted structure, a layered structure, and a composite structure consisting of a double twisted structure and a layered structure.

Since the steel cord has a ternary plating layer of copper, zinc, and iron, the components that make up the plating layer can play a role in increasing the adhesion between the rubber and the steel cord. Even when the content of the cobalt compound in the composition is small (0.01 parts by mass or less per 100 parts by mass of the rubber component), high adhesion can be achieved.
The steel cord may be further subjected to surface treatment such as adhesive treatment from the viewpoint of suitably ensuring adhesion to the rubber composition. When using an adhesive treatment, for example, an adhesive treatment such as the trade name "Chemlock" (registered trademark) manufactured by Lord Co. is preferable.

Alternatively, for example, a steel filament having a surface N atom content of 2 atomic % or more and 60 atomic % or less and a surface Cu/Zn ratio of 1 or more and 4 or less can be used. Also, in the metal filament 1, the amount of phosphorus contained as an oxide up to 5 nm of the outermost layer of the filament radially inward of the filament is 7.0 atomic % or less in terms of the total amount excluding the amount of C. is mentioned.

The metal contained in the rubber-metal composite of the present invention is a metal whose steel cord surface is coated with three-dimensional plating of copper, zinc, and iron (three-dimensionally plated metal). More specifically, the metal is a steel cord containing one or more steel filaments as described above, wherein the filaments include a steel filament base material and a coating (plating) that partially or wholly coats the steel filament base material. layer), wherein the coating comprises brass consisting of copper and zinc, the coating is reinforced with iron, the iron is present in the brass as particles, the particles are 10-10000 nano More preferred are steel cords characterized by having metric sizes. More preferably, said particles have a size between 20 and 5000 nanometers. By "iron-reinforced" is meant that the iron is not derived from the filamentary steel substrate.
Here, the brass is composed of copper and zinc, preferably contains at least 63% by mass of copper, the remainder being zinc, more preferably 65% by mass or more of copper, 67% by mass or more of copper.
In addition, the amount of iron in the coating (plating layer) is 1% or more by mass compared to the total mass of brass and iron, and preferably less than 10% by mass. More preferably the amount is at least 3% by weight and less than 9% by weight compared to the total weight of brass and iron.
More preferably, the steel cord is characterized in that said coating is substantially free of zinc-iron alloys.

In the steel cord comprising one or more steel filaments as described above, the amount of phosphorus present on the surface of the filaments, in other words, the amount of phosphorus in the coating (plating layer) is P _s , and the amount of phosphorus on the surface of the filaments is The amount of iron present, in other words the amount of iron in the coating (plating layer) is Fe _s and the amount of (P _s +Fe _s ) is the amount of phosphorus and It is determined by gently etching the surface of the filament with a weak acid that dissolves iron.
(a) About 5 grams of steel cord is weighed, cut into pieces of about 5 cm and introduced into a test tube.
(b) Add 10 ml of 0.01 molar hydrochloric acid HCl.
(c) Shake the sample with the acid solution for 15 seconds.
(d) Measure the amount present in solution by ICP-OES.
Here, ICP-OES means (0;0;0), (2;0.02;1), (5;0.1;2), (10;0.5; 5) Refers to optical emission spectroscopy (ICP-OES) using all standard solutions of (Cu; Fe; Zn) in mg/L.
(e) Shows the mass of (P _s +Fe _s ) per unit of filament steel surface area in milligrams per square meter (mg/m ² ). The result is sometimes called (Fe _s +P _s ).
The amount of phosphorus present on the surface of the filament, in other words, the amount of phosphorus in the coating (plating layer) is 4 mg/m ² or less, but preferably greater than zero to improve adhesion. That is, 0<P _s ≦4 mg/m ² . More preferably, the amount of phosphorus (P _s ) is less than 4 mg/m ² (P _s <4 mg/m ² ).
Higher amounts of phosphorus _Ps reduce adhesion layer growth. The amount of phosphorus _Ps may be lower than 3 mg/m ² , and even better lower than 1.5 mg/m ² .
In a further preferred embodiment, the amount of iron present on the surface of the filaments is preferably 30 mg/m ² or more, more preferably when more than 35 mg/m ² of iron is present on the surface, more than 40 mg/m ² Even more preferred is when the iron is present on the surface.
Also, the mass ratio (Fe _s /P _s ) of the amount of iron present on the surface of the filament to the amount of phosphorus present on the surface of the filament is preferably greater than 27.
The filament surface coating mass SCW is the sum of the masses of brass and iron present in the coating per unit of surface area, the coating mass is expressed in grams per square meter, and the mass ratio [Fe _s /(SCW ×P _s )] is preferably greater than 13.
A method of obtaining steel filaments in which the iron is present as particles in the brass involves wet wire drawing an intermediate wire having a brass coating reinforced with iron particles, followed by wet wire drawing the wire through a smaller die in a lubricant. to a final diameter of 0.28 mm to obtain a steel filament.
Lubricants generally contain high pressure additives containing phosphorus in an organic compound.
Here, the dies to be used may be Set-D dies in which at least the head die is a sintered diamond die and the remaining dies are tungsten carbide dies. The steel cord is preferably wire-drawn with a diamond die.

Since the rubber composition of the present invention can suppress metal corrosion even after a certain period of time has passed since the metal is coated, for example, the product is distributed in a state where the metal cord is coated with the rubber composition, and the product is distributed at the distribution destination. It can be vulcanized to produce a vulcanized rubber-metal composite. In addition, the vulcanized rubber-metal composite produced in this way has suppressed corrosion of the metal, so that the vulcanized rubber-metal adhesion is less likely to be impaired, and the composite is excellent in durability.

As a method for coating the steel cord with the rubber composition, for example, the following methods can be used.
A predetermined number of ternary-plated steel cords are arranged in parallel at predetermined intervals, and the steel cords are coated from above and below with an uncrosslinked rubber sheet having a thickness of about 0.5 mm made of the rubber composition of the present invention. to obtain the precursor. The resulting precursor (unvulcanized rubber-metal composite) is vulcanized. The vulcanization conditions are, for example, a temperature of about 160° C. for about 20 minutes; or a temperature of about 145° C. for about 40 minutes.
The composite of vulcanized rubber and steel cord thus obtained has excellent vulcanized rubber-metal adhesion.

The vulcanized rubber-metal composite of the present invention, which has excellent adhesiveness, is suitably used as a reinforcing material for rubber articles that require strength, such as various automobile tires, crawlers, and hoses. In particular, it is suitably used as a reinforcing member for belts of various automobile radial tires, carcass plies, wire chafers, and the like.

<Tire>
The tire of the invention comprises the vulcanized rubber-metal composite of the invention.
Therefore, the tire of the present invention is excellent in fuel efficiency.
The method for manufacturing the tire of the present invention is not particularly limited as long as it is a method capable of manufacturing the tire so that the vulcanized rubber-metal composite of the present invention is included in the tire.
In general, a rubber composition containing various components is processed into each member in an unvulcanized stage, and then pasted and molded on a tire molding machine by an ordinary method to form a green tire. The raw tire is heated and pressurized in a vulcanizer to produce a tire. For example, after kneading the rubber composition of the present invention, the resulting rubber composition is used to rubberize three-dimensionally plated steel cords to form unvulcanized belt layers, unvulcanized carcasses, and other unvulcanized belt layers. A tire is obtained by laminating the vulcanized members and vulcanizing the unvulcanized laminate.
The gas to be filled in the tire may be normal air, air with adjusted oxygen partial pressure, or inert gas such as nitrogen, argon, or helium.
The content of cobalt atoms in the tire of the present invention is preferably 1% by mass or less. The content of cobalt atoms in the tire can be said to be 0% by mass if the rubber composition used for tire production does not contain a cobalt-containing compound and the metal of the vulcanized rubber-metal composite does not contain cobalt. The content of cobalt atoms in the tire can be measured, for example, by a method of measuring the element content of each member constituting the tire.

<Crawler, hose>
The crawlers and hoses of the present invention comprise the vulcanized rubber-metal composite of the present invention.
The vulcanized rubber of the present invention - a chemical product containing a metal composite contains the vulcanized rubber of the present invention - a metal composite, so it is excellent in low loss properties.
Examples of chemical products include rubber products for chemical products other than tires containing vulcanized rubber-metal composites, and specific examples include rubber products requiring strength such as crawlers and hoses.

[Preparation of rubber composition]
(Example 1, Comparative Examples 1, 2, 5)
According to the compounding recipe shown in Table 1, first, ingredients other than the methylene donor, zinc oxide, sulfur and vulcanization accelerator are kneaded in a Banbury mixer, and the mixture is discharged when the temperature reaches 160°C. Next, a methylene donor, zinc oxide, sulfur and a vulcanization accelerator are added and mixed to the resulting mixture using a Kansai Roll 6-inch open roll kept at 70°C to prepare a rubber composition for steel cord coating. . However, in Comparative Example 1, an organic acid cobalt salt is blended. The unit of numerical values in the compounding recipes in Table 1 is parts by mass.

(Comparative Examples 3 and 4)
According to the compounding recipe shown in Table 1, first, ingredients other than the methylene donor, zinc oxide, sulfur and vulcanization accelerator were kneaded in a Banbury mixer, and the mixture was discharged when the temperature reached 160°C. Next, a methylene donor, zinc oxide, sulfur and a vulcanization accelerator were added and mixed to the resulting mixture using a Kansai Roll 6-inch open roll kept at 70°C to prepare a rubber composition for steel cord coating. bottom. However, in Comparative Example 4, an organic acid cobalt salt was blended. The unit of numerical values in the compounding recipes in Table 1 is parts by mass.

(1) Natural rubber: SMR-CV60
(2) Carbon black: HAF grade carbon black, manufactured by Asahi Carbon Co., Ltd., trade name “Asahi #70L”, DBP absorption: 75 cm ³ /100 g, nitrogen adsorption specific surface area: 84 m ² /g
(3) Silica: manufactured by Tosoh Silica Co., Ltd., trade name “Nip Seal AQ” (CTAB specific surface area = 155 m / g)
(4) Organic acid cobalt salt: OMG Co., Ltd., "Manobond C" (composite salt in which part of the organic acid in the cobalt salt of the organic acid is replaced with boric acid, cobalt content: 22.0% by mass)
(5) Phenolic resin: manufactured by Sumitomo Bakelite Co., Ltd., trade name “Sumilite Resin PR-50235”
(6) Hexamethoxymethylmelamine (HMMM): methylene donor, manufactured by ALLNEX, trade name "CYREZ 964LF"
(7) SPB: syndiotactic polybutadiene, manufactured by JSR Corporation, trade name "RB840"
(8) Zinc oxide: manufactured by Seido Chemical Industry Co., Ltd., trade name “zinc oxide type 2”
(9) Sulfur: insoluble sulfur: manufactured by Flexis, trade name “Cristex HS OT-20”
In addition to the components shown in Table 1, the rubber composition contains anti-aging agents, vulcanization accelerators, stearic acid, and alkylphenol resins as other components.

[Preparation of vulcanized rubber-metal composite]
(Example 1, Comparative Examples 3 and 5)
A steel cord whose surface is coated with ternary plating of copper, zinc, and iron and contains about 1% by mass of iron can be used as the metal. This ternary plated steel cord is obtained using a Set-D die, and more specifically, manufactured by the method described in paragraphs [0065] to [0070] of WO 2020/156967. .
The ternary plated steel cord is coated with the prepared rubber composition to produce an unvulcanized rubber-metal composite (unvulcanized steel cord topping product).
A vulcanized rubber-metal composite can be produced by vulcanizing an unvulcanized rubber-metal composite.

(Comparative Examples 1 and 2)
The steel filament is plated repeatedly with Cu, Zn, and Co in this order so that the Cu content in the plating is 67.0% by mass, the Zn content is 29.0% by mass, and the Co content is 4.0% by mass. alloy plated steel filament. Furthermore, after that, only the extreme surface of the ternary alloy plating layer is subjected to heavy working (surface treatment) by wire drawing with a diamond die, and then a steel cord, which is a twisted cord, is produced.

(Comparative Example 4)
A steel cord whose surface was coated with brass plating (copper-zinc plating) was used as the metal.
The brass-plated steel cord was coated with the prepared rubber composition to produce an unvulcanized rubber-metal composite (unvulcanized steel cord topping product).
The unvulcanized rubber-metal composite was vulcanized to prepare a vulcanized rubber-metal composite.

<Evaluation>
1. Adhesion (1) Initial adhesion Vulcanized rubber immediately after vulcanization when vulcanization is performed at half the vulcanization time of normal vulcanization conditions (time to reach TC90 plus 5 minutes) - steel from metal composite pull out the code. The coating state of the vulcanized rubber adhering to the steel cord was observed by visual observation. The coating amount of the vulcanized rubber of the example is expressed as an index of adhesion (initial adhesion). Table 1 shows the results. The acceptable range is 100 or more. TC90 means the time for a specific rubber to reach 90% of the maximum torque on the rheometer curve at the vulcanization temperature.

(2) Wet heat deterioration The vulcanized rubber-metal composite immediately after vulcanization is stored in a steam environment at 120°C for 2 days, and the steel cord is pulled out from the vulcanized rubber-metal composite after storage. The coating state of the vulcanized rubber adhering to the steel cord was observed by visual observation. The coating amount of the vulcanized rubber of the example is expressed as an index of adhesion (wet heat deterioration). Table 1 shows the results. The allowable range is 500 or more, preferably 980 or more.

2. Low heat build-up (low loss) and steering stability (Example 1, Comparative Examples 1, 2, 5)
The rubber composition is vulcanized at 160°C for 15 minutes to obtain a vulcanized rubber. Using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd., the tan δ (loss tangent) of the vulcanized rubber at 25° C. is measured under conditions of an initial load of 1600 mN, a strain of 1%, and a frequency of 52 Hz. The reciprocal of the tan δ of the sample of Comparative Example 4 being 100, the evaluation result is expressed as a low heat build-up index. Table 1 shows the results. A larger value indicates lower rolling resistance and lower loss. The allowable range is 100 or less.
The storage modulus (E') is measured under the same conditions. The index when E' of the sample of Comparative Example 4 is 100 is shown as the steering stability index. It is considered that the larger the steering stability index, the larger the E' value and the better the steering stability. Table 1 shows the evaluation results.

(Comparative Examples 3 and 4)
The rubber composition was vulcanized at 160°C for 15 minutes to obtain a vulcanized rubber. Using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd., the tan δ (loss tangent) of the vulcanized rubber at 25° C. was measured under conditions of an initial load of 1600 mN, a strain of 1%, and a frequency of 52 Hz. The reciprocal of the tan δ of the sample of Comparative Example 4 being 100, the evaluation result was expressed as a low heat build-up index. Table 1 shows the results. A larger value indicates lower rolling resistance and lower loss. The allowable range is 100 or less.
The storage modulus (E') was measured under the same conditions. The index when E' of the sample of Comparative Example 4 is 100 is shown as the steering stability index. It is considered that the larger the steering stability index, the larger the E' value and the better the steering stability. Table 1 shows the evaluation results.

3. Crack growth resistance (Example 1, Comparative Examples 1, 2, 5)
The rubber composition is vulcanized at 160° C. for 15 minutes to prepare a vulcanized rubber sheet having a thickness of 2 mm, and the crack propagation resistance after deterioration of each vulcanized rubber is evaluated.
The deterioration condition is to leave the rubber composition in an oven at 100° C. for 24 hours.
After the above deterioration, the vulcanized rubber sheet is subjected to a constant stress fatigue test using a fatigue tester FT-3100 manufactured by Ueshima Seisakusho, and the number of times until the vulcanized rubber sheet breaks is measured. The results are shown as an index (crack growth resistance index) with Comparative Example 4 being 100. A larger index value indicates that the vulcanized rubber sheet is more excellent in crack propagation resistance after deterioration. The acceptable range is 100 or more.
Table 1 shows the results.

(Comparative Examples 3 and 4)
The rubber composition was vulcanized at 160° C. for 15 minutes to prepare a vulcanized rubber sheet having a thickness of 2 mm, and the crack propagation resistance after deterioration of each vulcanized rubber was evaluated.
The deterioration condition is to leave the rubber composition in an oven at 100° C. for 24 hours.
After the above deterioration, the vulcanized rubber sheet was subjected to a constant stress fatigue test using a fatigue tester FT-3100 manufactured by Ueshima Seisakusho, and the number of times until the vulcanized rubber sheet fractured was measured. The results are shown as an index (crack growth resistance index) with Comparative Example 4 being 100. A larger index value indicates that the vulcanized rubber sheet is more excellent in crack propagation resistance after deterioration. The acceptable range is 100 or more.
Table 1 shows the results.

In Table 1, "BX" in the "Steel cord type" column is a ternary plated steel cord in which the metal of the vulcanized rubber-metal composite is coated with ternary plating of copper, zinc, and iron on the surface. indicates that there is "T/L" in the same column indicates that the metal of the vulcanized rubber-metal composite is ternary plated steel cord coated with ternary platings of copper, zinc, and cobalt. "B" in the same column indicates that the metal of the vulcanized rubber-metal composite is steel cord coated with brass plating (copper-zinc plating).

As is clear from Table 1, the vulcanized rubber-metal composite of Example 1 is superior in adhesion to the vulcanized rubber-metal composites of Comparative Examples 1-5.
In the example of Patent Document 3 (WO 2020/156967), as shown in FIG. 1 (Fig. 3a of Patent Document 4), as the amount of iron in the coating by ternary plating increases, Vulcanized rubber-metal adhesion is reduced. On the other hand, the vulcanized rubber-metal composite according to Example 1 can improve the vulcanized rubber-metal adhesion, so regardless of the increase or decrease in the amount of iron in the coating, vulcanization of a certain level or more Rubber-to-metal adhesion can be achieved.
In FIG. 1, "1-W" etc. on the horizontal axis refer to the samples shown in Table II of paragraph number [0075] of Patent Document 4, and the larger the number, the larger the amount of iron in the coating. Also, the Z-Score on the vertical axis indicates the superiority or inferiority of adhesion, and the larger the value, the better the vulcanized rubber-metal adhesion.

In addition, as is clear from Table 1, the vulcanized rubber-metal composite of Example 1 has better steering stability, low loss and resistance than the vulcanized rubber-metal composites of Comparative Examples 1-5. Each index of crack growth is large. This means that if the vulcanized rubber-metal composite of Example 1 is used for manufacturing a tire, the steering stability, fuel efficiency and crack growth resistance of the tire are improved in a well-balanced manner.

The rubber composition according to the present invention has a cobalt compound content of 0.01 parts by mass or less per 100 parts by mass of the rubber component, thereby contributing to reduction of environmental load.

The vulcanized rubber-metal composite of the present invention is excellent in vulcanized rubber-metal adhesion and low loss, so it can be used as a reinforcing material for rubber articles that particularly require strength, such as various automobile tires, crawlers, and hoses. It is preferably used. Among them, it is suitably used as a reinforcing member for various automotive radial tire belts, carcass plies, wire chafers, etc., and the vulcanized rubber-metal composite of the present invention is used to produce tires that are excellent in fuel efficiency. .

Claims (22)

A vulcanized rubber-metal composite comprising a metal and a vulcanized rubber covering the metal,
The vulcanized rubber contains a rubber component, a filler, a thermosetting resin, and a methylene donor, and the content of the cobalt-containing compound is 0.01 parts by mass or less per 100 parts by mass of the rubber component. A vulcanized rubber of a rubber composition,
The metal is a vulcanized rubber-metal composite in which the surface of the steel cord is coated with ternary plating of copper, zinc, and iron. The vulcanized rubber-metal composite according to claim 1, wherein the amount of said iron in said coating is 1% by mass or more and less than 10% by mass of the total mass of said copper, said zinc and said iron. 3. The vulcanized rubber-metal composite according to claim 1 or 2, wherein the amount of phosphorus in the coating is more than 0 mg/m ² and not more than 4 mg/m ² . The vulcanized rubber-metal composite according to any one of claims 1 to 3, wherein the steel cord is wire-drawn with a diamond die. 5. The rubber composition according to any one of claims 1 to 4, further comprising at least one vulcanization accelerator selected from the group consisting of thiuram-based vulcanization accelerators and sulfenamide-based vulcanization accelerators. A vulcanized rubber-metal composite as described. The vulcanized rubber-metal composite according to any one of claims 1 to 5, wherein the rubber composition further contains 0.5 to 8 parts by mass of a reinforcing resin with respect to 100 parts by mass of the rubber component. body. Any one of claims 1 to 6, wherein the rubber composition contains carbon black, and the content of carbon black is 35 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the rubber component of the rubber composition. The vulcanized rubber-metal composite according to Item. The vulcanized rubber-metal according to claim 7, wherein the carbon black has a nitrogen adsorption specific surface area of 70 m ² /g or more and 90 m ² /g or less, and a dibutyl phthalate absorption amount of 50 mL/100 g or more and 110 mL/100 g or less. Complex. The vulcanized rubber-metal composite according to any one of claims 1 to 8, wherein the content of the cobalt-containing compound in the rubber composition is 0.00 parts by mass with respect to 100 parts by mass of the rubber component. body. The content of the thermosetting resin in the rubber composition is more than 4 parts by mass and 20 parts by mass or less with respect to 100 parts by mass of the rubber component, according to any one of claims 1 to 9. Vulcanized rubber-metal composite. The vulcanized rubber-metal composite according to any one of claims 6 to 10, wherein the reinforcing resin is syndiotactic-1,2-polybutadiene. The vulcanized rubber-metal according to any one of claims 5 to 11, wherein the mass ratio (thiuram-based vulcanization accelerator/thermosetting resin) in the rubber composition is 0.02 or more and less than 0.12. Complex. The vulcanized rubber-metal composite according to any one of claims 1 to 12, wherein the thermosetting resin comprises a phenolic resin. The vulcanized rubber-metal composite according to any one of claims 7 to 13, wherein the filler contains the carbon black and silica. 15. The vulcanized rubber-metal composite according to claim 14, wherein the silica content in the rubber composition is more than 0 parts by mass and 15 parts by mass or less with respect to 100 parts by mass of the rubber component. The vulcanized rubber-metal composite according to any one of claims 5 to 15, wherein said rubber composition comprises N-cyclohexyl-2-benzothiazolylsulfenamide. The vulcanized rubber-metal composite according to any one of claims 13 to 16, wherein the phenol resin contains two or more phenol resins and at least an alkylphenol resin. 18. The vulcanized rubber-metal composite of claim 17, wherein the phenolic resin comprises an unmodified phenol-formaldehyde resin and an alkylphenol-formaldehyde resin. A tire comprising the vulcanized rubber-metal composite according to any one of claims 1-18. 20. The tire according to claim 19, wherein the content of cobalt atoms is 1% by mass or less. A hose comprising the vulcanized rubber-metal composite according to any one of claims 1-18. A crawler comprising the vulcanized rubber-metal composite according to any one of claims 1-18.

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