JP7312628B2 - Rubber composition and rubber products - Google Patents

Description

The present invention relates to rubber compositions and rubber products.

Rubber products are used in a wide variety of applications, including tires for automobiles and aircraft, materials for civil engineering and construction, materials for various industrial products, and general-purpose daily necessities. Among these, rubber materials used for automobile tires and the like are required to have a high elastic modulus.
For example, Patent Literature 1 discloses a rubber composition using a phenolic resin having a specific structure from the viewpoint of obtaining a rubber vulcanizate for tires with high elastic modulus and high strength.

JP 2007-269843 A

Here, in a tire using a rubber composition, it is known that the tire as a whole undergoes deflection deformation at the ground contact portion during running, constantly repeating deformation and recovery, thereby causing hysteresis loss. That is, a tire using a rubber composition with small hysteresis loss has low rolling resistance and good fuel efficiency.
On the other hand, in the technique disclosed in Patent Document 1, although the elastic modulus can be increased by blending a phenolic resin into the rubber composition, the hysteresis loss tends to be insufficient.

As a result of intensive studies from the viewpoint of achieving both a high elastic modulus and a good hysteresis loss, the inventors found that it is effective to combine a specific phenolic resin and a specific tetrazine compound, and completed the present invention.

［式（１）中、Ｘ^１及びＸ^２は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。]
を有する、ゴム組成物を提供する。 The present invention
a phenolic resin having an unsaturated bond;
a tetrazine compound represented by the general formula (1) or a salt thereof;

[In Formula (1), X ¹ and X ² are the same or different and represent a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
To provide a rubber composition having

The present invention also provides a rubber product using the above rubber composition.

The present invention also provides a tire using the above rubber composition.

Further, the present invention provides a step (X) of mixing raw material components containing a rubber component, a phenolic resin having an unsaturated bond, and a tetrazine compound represented by the general formula (1) or a salt thereof;
a step (Y) of mixing the mixed raw material components with a vulcanizing agent;
including
The step (X) is
The step (X-1) of simultaneously mixing the rubber component, the tetrazine compound or its salt represented by the general formula (1), and the phenolic resin having an unsaturated bond, or the step (X-2) of mixing the mixture obtained by mixing the rubber component and the phenolic resin having the unsaturated bond with the tetrazine compound or its salt represented by the general formula (1).
A method for producing a rubber composition is provided.

［式（１）中、Ｘ^１及びＸ^２は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。]
を有する、ゴム組成物を提供する。

[In Formula (1), X ¹ and X ² are the same or different and represent a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
To provide a rubber composition having

ADVANTAGE OF THE INVENTION According to this invention, the rubber composition which can make high elastic modulus and favorable hysteresis loss compatible is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed typically a part of cross section of the tire of this embodiment. 1 is a ¹ H-NMR chart of phenol resin 1. FIG. 1 is a ¹ H-NMR chart of phenol resin 2. FIG. 1 is a ¹ H-NMR chart of phenolic resin 3. FIG. 1 is a ¹ H-NMR chart of phenol resin 4. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
<Rubber composition>
The rubber composition of the present embodiment contains at least a phenolic resin (A) having an unsaturated bond (hereinafter also referred to as "phenolic resin (A)") and a tetrazine compound represented by general formula (1) or a salt thereof (hereinafter also referred to as "tetrazine compound (B)").

[Phenolic resin (A)]
In this embodiment, the phenolic resin (A) has an unsaturated bond. The phenolic resin (A) having an unsaturated bond includes, for example, those in which a substituent having an unsaturated bond is bonded to an aromatic ring, a compound in which a compound having an unsaturated bond is bonded instead of a hydrogen atom of a hydroxyl group, or a substituent derived from an aldehyde as a raw material having an unsaturated bond.

By having an unsaturated bond, the phenol resin (A) can cause an addition reaction with the tetrazine compound (B) described below. Since the skeleton of the phenolic resin (A) is rigid, it is possible to achieve a high elastic modulus of the vulcanizate, while the tetrazine compound (B) enters between the three-dimensional structures of the vulcanizate of the phenolic resin (A). As a result, it is presumed that the characteristics of rubber are maintained and appropriate viscoelasticity is secured, resulting in good hysteresis loss characteristics.

Moreover, the phenol resin (A) preferably has at least one or more structural units represented by the following general formula (2).

［式（２）中、Ｒ^１は不飽和結合を有する置換基を示す。］

[In Formula (2), R ¹ represents a substituent having an unsaturated bond. ]

In this embodiment, it is known that the hysteresis loss in the frequency domain that affects the rolling resistance of the tire is generally correlated with tan δ of dynamic viscoelasticity at 60°C, and can be evaluated using tan δ of dynamic viscoelasticity at 60°C. The lower the tan δ at 60°C, the lower the hysteresis loss that affects the rolling resistance of the tire and the better the fuel efficiency.

In formula (2), the unsaturated bond of R ¹ is preferably a carbon-carbon unsaturated bond (a carbon-carbon double bond and a carbon-carbon triple bond). Further, R ¹ is more preferably a hydrocarbon group having a linear or branched unsaturated bond having 2 to 25 carbon atoms, and any of the hydrogen atoms bonded to the carbon atoms may be substituted with an atom other than a hydrogen atom. These may be used individually by 1 type, and may be used in mixture of 2 or more types.

Moreover, the phenol resin (A) preferably has at least one or more structural units represented by the following general formula (3).

［式（３）中、Ｒ^２は不飽和結合を有する置換基を示す。Ｒ^３は、水素、アルキル基、アリール基、水酸基、エーテル基、アミノ基、カルボキシル基、エステル基、アルデヒド基、スルフィド基、チオール基、またはメチロール基のいずれかを示す。］

[In Formula (3), R ² represents a substituent having an unsaturated bond. ^R3 represents hydrogen, alkyl group, aryl group, hydroxyl group, ether group, amino group, carboxyl group, ester group, aldehyde group, sulfide group, thiol group, or methylol group. ]

In formula (3), the unsaturated bond of R ² is preferably a carbon-carbon unsaturated bond (a carbon-carbon double bond and a carbon-carbon triple bond). Further, R ² is more preferably a hydrocarbon group having a linear or branched unsaturated bond with 2 to 25 carbon atoms, and any of the hydrogen atoms bonded to the carbon atoms may be substituted with an atom other than a hydrogen atom. These may be used individually by 1 type, and may be used in mixture of 2 or more types.
The alkyl group in R ³ is preferably a straight-chain or branched hydrocarbon group having 1 to 25 carbon atoms, and any of the hydrogen atoms bonded to the carbon atoms may be substituted with an atom other than a hydrogen atom.

The phenolic resin (A) is a condensate of phenols and aldehydes, and as a method of obtaining a phenolic resin having an unsaturated bond, for example, it may be obtained by reacting a phenol having an unsaturated bond or an aldehyde having an unsaturated bond, or reacting a phenolic resin having no unsaturated bond with a compound having an unsaturated bond to introduce an unsaturated bond. These methods may be used singly or in combination.

Phenols having an unsaturated bond include those having an unsaturated bond in the side chain. Examples include vinylphenol, allylphenol, eugenol, curcumin, coumaric acid, hydroxycinnamic acid and its derivatives, cardanol and its unpurified cashew nut shell liquid, urushiol and its unpurified lacquer, thithiol, and laccol. Vinylphenol, allylphenol, cardanol and cashew nut shell liquid are preferred, and cardanol and cashew nut shell liquid are particularly preferred. These may be used alone or in combination, and may be used in combination with phenols containing no unsaturated bond. Examples of phenols containing no unsaturated bond include, but are not limited to, phenol, cresol, xylenol, dihydroxybenzene, naphthol, saturated alkylphenols such as ethylphenol, propylphenol, butylphenol, pentylphenol, hexylphenol, octylphenol, and nonylphenol, bis(hydroxyphenyl)methane, bis(hydroxyphenyl)ethane, bis(hydroxyphenyl)propane, bis(hydroxyphenyl)butane, bis(hydroxyphenyl)cyclohexane, bis(hydroxyphenyl)sulfone, and bis(hydroxyphenyl). bisphenols such as propylbenzene and bis(hydroxyphenyl)ketone; Moreover, when obtaining a phenolic resin containing unsaturated bonds by other methods, only phenols containing no unsaturated bonds may be used. Preferred phenols containing no unsaturated bond are phenol, cresol, xylenol, dihydroxybenzene, naphthol, butylphenol, octylphenol, bis(hydroxyphenyl)methane and bis(hydroxyphenyl)propane. These may be used singly or in combination.

Aldehydes having an unsaturated bond include, for example, acrolein, allylaldehyde, crotonaldehyde and the like. These may be used alone or in combination, and may be used in combination with aldehydes containing no unsaturated bond. Aldehydes containing no unsaturated bond include, but are not limited to, formaldehyde, paraformaldehyde, trioxane, tetraoxymethylene, polyoxymethylene, hexamethylenetetramine, acetaldehyde, paraldehyde, propionaldehyde, butyraldehyde, caproaldehyde, octylaldehyde, chloral, furfural, glyoxal, benzaldehyde, phenylacetaldehyde, o-tolualdehyde, hydroxybenzaldehyde, and the like. Alternatively, p-xylylene dichloride, p-xylylene dimethyl ether, and furfuryl alcohol, which react with phenols like aldehydes, may be used. When obtaining a phenolic resin containing unsaturated bonds by other methods, only aldehydes containing no unsaturated bonds may be used. The aldehydes containing no unsaturated bond are preferably formaldehyde, paraformaldehyde, hexamethylenetetramine, benzaldehyde, hydroxybenzaldehyde, furfural, furfuryl alcohol, paraxylylene dichloride, and paraxylylene dimethyl ether, and particularly preferably formaldehyde, paraformaldehyde, and hexamethylenetetramine. These may be used singly or in combination.

Conditions for reacting phenols and aldehydes to obtain a phenolic resin (A) having an unsaturated bond are not particularly limited, but examples include a method of heating the above phenols and aldehydes at 50°C to 200°C. The molar ratio of phenols and aldehydes (F/P molar ratio) is not particularly limited, but for example, aldehydes may be 0.1 mol to 4.0 mol, preferably 0.2 mol to 2.0 mol, particularly preferably 0.3 mol to 1.0 mol, per 1 mol of phenol. As a catalyst, the reaction is preferably carried out in the presence of an organic acid, phosphoric acid, organic phosphonic acids, transition metal salt, or basic catalyst. Organic acids include, for example, acetic acid, oxalic acid, formic acid, lactic acid, and malic acid. Examples of organic phosphonic acids include aminopolyphosphonic acids such as ethylenediaminetetrakismethylenephosphonic acid, ethylenediaminebismethylenephosphonic acid, aminotrismethylenephosphonic acid, β-aminoethylphosphonic acid N,N-diacetic acid, aminomethylphosphonic acid N,N-diacetic acid, 1-hydroxyethylidene-1,1′-diphosphonic acid, and 2-phosphonobutane-1,2,4-tricarboxylic acid. Examples of transition metal catalysts that can be used include inorganic salts and organic acid salts of transition metals such as titanium, iron, zinc, nickel, cobalt, copper, chromium, and manganese. Examples of basic catalysts that can be used include amines such as sodium hydroxide, lithium hydroxide, potassium hydroxide, aqueous ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, methylethylamine and triethylamine, oxides and hydroxides of alkaline earth metals such as calcium, magnesium and barium, and alkaline substances such as sodium carbonate and hexamethylenetetramine. The apparatus for producing the phenolic resin (A) having unsaturated bonds is not particularly limited. For example, the reaction may be carried out in a vessel such as a reactor equipped with a heater, a cooler and a stirrer, or the reaction may be carried out continuously using a continuous mixer or the like.

The compound having an unsaturated bond in the case of obtaining a phenolic resin (A) having an unsaturated bond by reacting a phenolic resin having no unsaturated bond with a compound having an unsaturated bond includes, for example, an epoxy compound having an unsaturated bond, a chloride, an isocyanate compound, and a drying oil. Examples of epoxy compounds having unsaturated bonds include vinyl glycidyl ether and allyl glycidyl ether. Examples of chlorides having unsaturated bonds include vinyl chloride and allyl chloride. Examples of isocyanate compounds having unsaturated bonds include methacryloyl isocyanate, methacryloyloxyethyl isocyanate, isocyanatoethyl methacrylate, and isocyanatoethyl acrylate. Examples include perilla oil, safflower oil, sunflower oil and the like. These may be used alone or in combination.

In addition, the phenolic resin (A) having unsaturated bonds may be modified with oil. Examples of oils used for modification include rosin oil, tall oil, and the like.

The ratio of peaks (peaks at 4.5 to 6.0 ppm) derived from unsaturated bonds in the ¹ H-NMR spectrum of the phenolic resin (A) is preferably 0.5% or more and 20% or less, more preferably 0.7% or more and 15% or less, more preferably 1% or more and 10% or less, of the total integrated value of peaks (peaks at 0.2 to 7.5 ppm) derived from hydrogen bonded to carbon atoms.
When the numerical value is equal to or higher than the above lower limit value, the reactivity becomes good, and by making the numerical value equal to or lower than the above upper limit value, good handleability can be maintained.

The number average molecular weight of the phenolic resin (A) is preferably 400-3000, more preferably 800-2000, even more preferably 1000-1800. Thereby, a resin having good handleability can be stably obtained.
By setting the number average molecular weight of the phenol resin (A) to the above lower limit or more, it is possible to improve compatibility with other compounding agents and maintain good handleability. On the other hand, by setting the number average molecular weight of the phenol resin (A) to the above upper limit or less, it is possible to prevent the viscosity from becoming too high, and to easily obtain good solubility in solvents.
The number average molecular weight is calculated by measuring with a differential refractometer as a detector under predetermined conditions using GPC (gel permeation chromatography) in the liquid chromatography method, and then converting with standard polystyrene.

The content of the phenol resin (A) is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, even more preferably 1 to 10% by mass, relative to the entire rubber composition.
By setting the content of the phenol resin (A) to the above lower limit or more, the elastic modulus of the vulcanized rubber composition can be increased.
On the other hand, the hysteresis loss of the vulcanized rubber can be kept low by setting the content of the phenol resin (A) to the above upper limit or less.

[Tetrazine compound (B)]
The tetrazine compound (B) is represented by general formula (1). This makes it possible to obtain a suitable hysteresis loss in rubber products using the rubber composition.

［式（１）中、Ｘ^１及びＸ^２は、同一または異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、またはアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。］

[In Formula (1), X ¹ and X ² are the same or different and represent a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]

Examples of the above alkyl groups include linear, branched or cyclic alkyl groups, and specific examples include linear or branched alkyl groups having 1 to 6 carbon atoms (especially 1 to 4 carbon atoms) such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 1-ethylpropyl, n-pentyl, neopentyl, n-hexyl, isohexyl, and 3-methylpentyl groups; cyclopropyl, cyclobutyl, cyclopentyl, Cyclic alkyl groups having 3 to 8 carbon atoms (especially 3 to 6 carbon atoms) such as cyclohexyl, cycloheptyl, cyclooctyl, and the like are included. Among them, linear or branched alkyl groups having 1 to 6 carbon atoms are preferred, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and n-pentyl groups are more preferred, and methyl or ethyl groups are even more preferred.

The above-mentioned alkylthio groups include linear, branched or cyclic alkylthio groups, such as methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, isobutylthio, s-butylthio, t-butylthio, 1-ethylpropylthio, n-pentylthio, neopentylthio, n-hexylthio, isohexylthio, and 3-methylpentylthio. thio group; cyclic alkylthio groups having 3 to 8 carbon atoms (especially 3 to 6 carbon atoms) such as cyclopropylthio, cyclobutylthio, cyclopentylthio, cyclohexylthio, cycloheptylthio, and cyclooctylthio groups; Among them, a methylthio, ethylthio, isopropylthio, or isobutylthio group is preferable, and a methylthio group or an ethylthio group is more preferable.

Examples of the above aralkyl groups include benzyl, phenethyl, trityl, 1-naphthylmethyl, 2-(1-naphthyl)ethyl, 2-(2-naphthyl)ethyl groups and the like. Among them, a benzyl group or a phenethyl group is preferable, and a benzyl group is more preferable.

Examples of the above aryl groups include phenyl, biphenyl, naphthyl, dihydroindenyl, 9H-fluorenyl groups, and the like. Among them, a phenyl group or a naphthyl group is preferable, and a phenyl group is more preferable.

Examples of the above arylthio groups include phenylthio, biphenylthio, and naphthylthio groups.

Examples of the above heterocyclic groups include 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrazinyl, 2-pyrimidyl, 4-pyrimidyl, 5-pyrimidyl, 3-pyridazyl, 4-pyridazyl, 4-(1,2,3-triazyl), 5-(1,2,3-triazyl), 2-(1,3,5-triazyl), 3-(1,2,4-triazyl), 5-(1,2,4-triazyl), 6-(1,2,4-triazyl), 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl, 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl, 2-quinoxa Lyl, 3-quinoxalyl, 5-quinoxalyl, 6-quinoxalyl, 7-quinoxalyl, 8-quinoxalyl, 3-cinnolyl, 4-cinnolyl, 5-cinnolyl, 6-cinnolyl, 7-cinnolyl, 8-cinnolyl, 2-quinazolyl, 4-quinazolyl, 5-quinazolyl, 6-quinazolyl, 7-quinazolyl, 8-quinazolyl, 1-phthalyl Radyl, 4-phthalazyl, 5-phthalazyl, 6-phthalazyl, 7-phthalazyl, 8-phthalazyl, 1-tetrahydroquinolyl, 2-tetrahydroquinolyl, 3-tetrahydroquinolyl, 4-tetrahydroquinolyl, 5-tetrahydroquinolyl, 6-tetrahydroquinolyl, 7-tetrahydroquinolyl, 8-tetrahydroquinolyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-furyl, 3-furyl, 2 -thienyl, 3-thienyl, 1-imidazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isoxazolyl, 4-isoxazolyl, 5- isoxazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 4-(1,2,3-thiadiazolyl), 5-(1,2,3-thiadiazolyl), 3-(1,2,5-thiadiazole), 2-(1,3,4-thiadiazole), 4-(1,2,3-oxadiazolyl), 5-(1,2,3-oxadiazolyl), 3-(1,2,4- oxadiazolyl), 5-(1,2,4-oxadiazolyl), 3-(1,2,5-oxadiazolyl), 2-(1,3,4-oxadiazolyl), 1-(1,2,3-triazolyl), 4-(1,2,3-triazolyl), 5-(1,2,3-triazolyl), 1-(1,2,4-triazolyl), 3-(1,2,4-triazolyl), 5- (1,2,4-triazolyl), 1-tetrazolyl, 5-tetrazolyl, 1-indolyl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl, 7-indolyl, 1-isoindolyl, 2-isoindolyl, 3-isoindolyl, 4-isoindolyl, 5-isoindolyl, 6-isoindolyl, 7-isoindolyl, 1-benzimidazolyl, 2-benzimidazolyl, 4-benzoy Midazolyl, 5-benzimidazolyl, 6-benzimidazolyl, 7-benzimidazolyl, 2-benzofuranyl, 3-benzofuranyl, 4-benzofuranyl, 5-benzofuranyl, 6-benzofuranyl, 7-benzofuranyl, 1-isobenzofuranyl, 3-isobenzofuranyl, 4-isobenzofuranyl, 5-isobenzofuranyl, 6-isobenzofuranyl, 7-isobenzofuranyl, 2-benzothienyl, 3-benzothienyl , 4-benzothienyl, 5-benzothienyl, 6-benzothienyl, 7-benzothienyl, 2-benzoxazolyl, 4-benzoxazolyl, 5-benzoxazolyl, 6-benzoxazolyl, 7-benzoxazolyl, 2-benzothiazolyl, 4-benzothiazolyl, 5-benzothiazolyl, 6-benzothiazolyl, 7-benzothiazolyl, 1-indazolyl, 3-indazolyl, 4-indazolyl, 5-yne Dazolyl, 6-indazolyl, 7-indazolyl, 2-morpholyl, 3-morpholyl, 4-morpholyl, 1-piperazyl, 2-piperazyl, 1-piperidyl, 2-piperidyl, 3-piperidyl, 4-piperidyl, 2-tetrahydropyranyl, 3-tetrahydropyranyl, 4-tetrahydropyranyl, 2-tetrahydrothiopyranyl, 3-tetrahydrothiopyranyl, 4-tetrahydrothiopyranyl nil, 1-pyrrolidyl, 2-pyrrolidyl, 3-pyrrolidyl, 2-tetrahydrofuranyl, 3-tetrahydrofuranyl, 2-tetrahydrothienyl, 3-tetrahydrothienyl and the like. Among them, pyridyl, furanyl, thienyl, pyrimidyl or pyrazyl is preferred, and pyridyl is more preferred.

In formula (1), X ¹ and X ² are preferably heterocyclic groups, and the heterocyclic groups are more preferably pyridyl groups, furanyl groups, 2-pyridyl groups and 3-pyridyl groups.

The salt of the tetrazine compound represented by formula (1) is not particularly limited, but examples thereof include inorganic acid salts such as hydrochlorides, sulfates and nitrates; organic acid salts such as acetates and methanesulfonates; alkali metal salts such as sodium salts and potassium salts; alkaline earth metal salts such as magnesium salts and calcium salts;

Furthermore, specific tetrazine compounds (B) include, for example, the following.
1,2,4,5-tetrazine, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3,6-bis(3-pyridyl)-1,2,4,5-tetrazine, 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine, 3,6-diphenyl-1,2,4,5-tetrazine, 3,6-dibenzyl-1,2,4,5-tetrazine, 3, 6-bis(2-furanyl)-1,2,4,5-tetrazine, 3-methyl-6-(3-pyridyl)-1,2,4,5-tetrazine, 3,6-bis(3,5-dimethyl-1-pyrazolyl)-1,2,4,5-tetrazine, 3,6-bis(2-thienyl)-1,2,4,5-tetrazine, 3-methyl-6-(2-pyridyl)-1,2,4,5- tetrazine, 3,6-bis(4-hydroxyphenyl)-1,2,4,5-tetrazine, 3,6-bis(3-hydroxyphenyl)-1,2,4,5-tetrazine, 3,6-bis(2-pyrimidinyl)-1,2,4,5-tetrazine, 3,6-bis(2-pyrazyl)-1,2,4,5-tetrazine and the like.

The rubber composition of the present embodiment may further contain the following components.

[Rubber component (C)]
The rubber component (C) includes natural rubber (NR), ethylene-propylene copolymer rubber (EPM), acrylic rubber (ACM), chlorinated polyethylene (CM), epichlorohydrin rubber (CO, ECO), chlorosulfonated polyethylene (CSM), isoprene rubber (IR), butyl rubber (IIR), nitrile rubber (NBR), and diene rubber.

As the diene-based rubber, any rubber containing a diene monomer as at least a part of the monomers constituting the rubber may be used. Specifically, natural rubber (NR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber {chlorinated butyl rubber (CI-IIR), brominated butyl rubber (Br-IIR), etc.}, ethylene-propylene-diene terpolymer rubber (EPDM), ethylene -Butadiene copolymer rubber (EBR), propylene-butadiene copolymer rubber (PBR), etc. can be used. These may be used individually by 1 type, and may be used in mixture of 2 or more types.
Of these, natural rubber, IR, SBR, BR, or a mixture of two or more selected from these is preferred.

The rubber composition of the present embodiment preferably contains 0.1 to 30 parts by mass of the phenol resin (A) and 0.01 to 10 parts by mass of the tetrazine compound (B), more preferably 0.5 to 20 parts by mass of the phenol resin (A) and 0.02 to 8 parts by mass of the tetrazine compound (B), and further comprises 1 to 10 parts by mass of the phenol resin (A) and 0.05 to 5 parts by mass of the tetrazine compound (B). Preferred.

[Filler (D)]
Examples of the filler (D) include, but are not limited to, inorganic fillers such as carbon black, silica, calcium carbonate, magnesium carbonate, alumina, magnesium oxide, aluminum hydroxide, magnesium hydroxide, talc, clay, and mica, and organic fillers. These may be used individually by 1 type, and may use 2 or more types together. Among these, from the viewpoint of increasing the elastic modulus, inorganic fillers are preferred, and carbon black and silica are more preferred.

The content of the filler (D) is preferably 20 to 100 parts by mass, more preferably 40 to 80 parts by mass, per 100 parts by mass of the rubber composition.
By making the content of the filler (D) equal to or more than the above lower limit value, the hardness of the rubber can be increased, and by making it equal to or less than the above upper limit value, fluidity can be easily obtained.

[Curing agent]
A curing agent is used to vulcanize the phenolic resin (A). The curing agent is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include hexamethylenetetramine, benzoxazine, resol-type phenolic resins, initial condensates of melamine/formaldehyde, and methyl etherified products of initial condensates of melamine/formaldehyde, such as hexamethoxymethylmelamine and pentamethoxymethylmelamine. These may be used individually by 1 type, and may be used in mixture of 2 or more types.

The content of the curing agent is preferably 1 to 60 parts by mass, more preferably 3 to 50 parts by mass, based on 100 parts by mass of the phenolic resin (A).
By making the content of the curing agent equal to or higher than the above lower limit, the vulcanization efficiency of the phenolic resin (A) and the rubber component is improved. On the other hand, by setting the content of the curing agent to the above upper limit or less, it is possible to suppress the remaining unreacted curing agent and maintain a high elastic modulus.

In the rubber composition of the present embodiment, as other optional components, compounding agents commonly used in the rubber industry, such as softeners, anti-aging agents, vulcanization accelerators, vulcanization accelerator auxiliaries, and coupling agents, etc., can be appropriately selected and blended within a range that does not impair the purpose of the present invention.

The method for producing a rubber composition of the present embodiment includes a step (X) of mixing raw material components including a rubber component (C), a phenolic resin (A), and a tetrazine compound (B), and a step (Y) of mixing the mixed raw material components and a vulcanizing agent, wherein the step (X) is a step (X-1) of simultaneously mixing the rubber component (C), the tetrazine compound (B), and the phenolic resin (A), or the rubber component (C) and the phenolic resin (A). with the tetrazine compound (B), which is any of the step (X-2).
That is, by adding the tetrazine compound (B) together with the phenolic resin (A) or adding the tetrazine compound (B) after the phenolic resin (A) during rubber kneading, a rubber composition capable of achieving both a high elastic modulus and a good hysteresis loss can be effectively and stably obtained. Then, the phenolic resin (A), the tetrazine compound (B) and other optional components are mixed and masticated, then a vulcanizing agent such as sulfur is blended, and the desired rubber composition is obtained by kneading, heating, extruding, etc. using a Banbury mixer, a roll, an intensive mixer, or a twin-screw extruder. By such a method, the phenol resin (A) and the tetrazine compound (B) react efficiently during the production of the rubber composition, and the elastic modulus of the rubber can be stably improved.
The reaction temperature between the phenol resin (A) and the tetrazine compound (B) is preferably 80° C. or higher and 250° C. or lower, more preferably 90° C. or higher and 200° C. or lower, even more preferably 100° C. or higher and 170° C. or lower. Thereby, both can be made to react stably.

The reaction between the phenolic resin (A) and the tetrazine compound (B) in the rubber composition of the present embodiment can be confirmed by diffracting ^{the 13} C-NMR spectrum. That is, in the ¹³ C-NMR spectrum, a new saturated aliphatic carbon-derived peak (around 25 ppm), which was not observed in the phenolic resin (A), is observed in the region (0 to 80 ppm) where the saturated aliphatic carbon-derived peak appears.
In addition, the present inventors assumed the thermal history applied during kneading of the rubber, and diffracted the ¹³ C-NMR spectrum of the modified phenol resin obtained by mixing the phenol resin (A) and the tetrazine compound (B) at 120 ° C. for 3 minutes using a kneader, and confirmed that a new saturated aliphatic carbon-derived peak that was not observed in the phenol resin (A) was observed in the region (0 to 80 ppm) where the saturated aliphatic carbon-derived peak appeared.

<Rubber products>
Rubber products obtained by vulcanizing the rubber composition of the present embodiment are applied to applications such as semiconductor parts, aircraft parts, automobile parts, castings, industrial machine parts, electronic parts, electrical parts, and mechanical parts. The method of molding the rubber product is not particularly limited, and examples thereof include known methods such as injection molding, compression molding, extrusion molding and cast molding. The form of the rubber product may be any form, and may be an intermediate molded product or a final molded product.

Above all, from the viewpoint of exhibiting the effect of achieving both high elastic modulus and hysteresis loss, the rubber product is preferably applied to automobile parts, more preferably tire members. Specifically, it can be suitably used for at least one of the tread portion, sidewall portion, carcass portion, belt portion, bead portion, rim cushion portion, run-flat reinforcing liner portion and other reinforcing rubber portions. When the rubber product of the present embodiment is used, for example, in the tread of a tire, the rubber composition of the present embodiment is extruded in the unvulcanized stage into the shape of the tread portion of the tire, and the unvulcanized tire is formed by laminating them together on a tire molding machine by a conventional method. After that, the unvulcanized tire can be heated and pressurized in a vulcanizer to obtain a tire. The molding temperature is preferably about 100 to 220°C, more preferably about 120 to 200°C, even more preferably about 130 to 190°C. If the molding temperature exceeds 190°C, the rubber may deteriorate, and if it is less than 100°C, molding may not be possible.

In this embodiment, the tire means a pneumatic tire, which can be used for passenger cars, trucks, buses, heavy machinery, and the like.
FIG. 1 is a cross-sectional view schematically showing a cross section of a tire. As shown in FIG. 1, the tire 100 includes a tread portion 11 that directly contacts the road surface during running, a shoulder portion 12 that serves as a shoulder portion of the tire 100 and protects the carcass 15, a sidewall portion 13 that serves as a side surface of the tire 100 and protects the carcass 15, a bead portion 14 for fixing the tire 100 to a rim portion provided on a wheel and fixing both ends of the carcass 15, a carcass 15 that forms the skeleton of the tire 100, and a belt portion 16. have An inner liner 18 is arranged inside the tire 100 . The belt portion 16 is arranged between the tread portion 11 and the carcass 16 and used to reinforce the tread portion 11 . Specifically, the belt portion 16 is arranged outside the crown portion of the carcass 15 and serves to increase the rigidity of the tread portion 11 . Further, the beat portion 14 of the tire 100 is provided with a beat core 17 for engaging the end portion of the carcass 15 so as to fold it and for receiving the tension of the carcass 15 during running and fixing it to the rim portion. A pneumatic tire is obtained by fixing the tire 100 to the rim portion of the wheel and retaining air between the tire 100 and the wheel.

［式（１）中、Ｘ ^１ 及びＸ ^２ は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。]
を有する、ゴム組成物。
２． 前記フェノール樹脂が一般式（２）で表される構造単位を、少なくとも１個以上有する１．に記載のゴム組成物。

［式（２）中、Ｒ ^１ は不飽和結合を有する置換基を示す。］
３． 式（２）中、前記不飽和結合が炭素－炭素不飽和結合である、２．に記載のゴム組成物。
４． 前記フェノール樹脂が一般式（３）で表される構造単位を、少なくとも１個以上有する１．に記載のゴム組成物。

［式（３）中、Ｒ ^２ は不飽和結合を有する置換基を示す。Ｒ ^３ は、水素、アルキル基、アリール基、水酸基、エーテル基、アミノ基、カルボキシル基、エステル基、アルデヒド基、スルフィド基、チオール基、またはメチロール基のいずれかを示す。］
５． 式（３）中、前記不飽和結合が炭素－炭素不飽和結合である、４．に記載のゴム組成物。
６． ^１ Ｈ－ＮＭＲスペクトルにおける前記不飽和結合に由来するピーク（４．５～６．０ｐｐｍのピーク）の割合が、炭素原子に結合した水素に由来するピーク（０．２～７．５ｐｐｍのピーク）の積算値合計の０．５％以上、２０％以下である、１．乃至５．いずれか一つに記載のゴム組成物。
７． 式（１）中、Ｘ ^１ 及びＸ ^２ が、複素環基である、１．乃至６．いずれか一つに記載のゴム組成物。
８． 前記ゴム組成物はゴム成分を含むものであって、前記ゴム成分１００質量部に対して、前記フェノール樹脂を０．１～３０質量部、前記テトラジン化合物またはその塩を０．０１～１０質量部含む、１．乃至７いずれ一つに記載のゴム組成物。
９． 前記ゴム成分が、ジエン系ゴムである、８．に記載のゴム組成物。
１０． タイヤ用部材に用いられる、１．乃至９．いずれか一つに記載のゴム組成物。
１１． １．乃至１０．いずれか一つに記載のゴム組成物を用いて成形されたゴム製品。
１２． １０．に記載のゴム組成物を用いて成形されたタイヤ用トレッド部材。
１３． １０．に記載のゴム組成物を用いて成形されたタイヤ用サイドウォール部材。
１４． １０．に記載のゴム組成物を用いて成形されたタイヤ用ビード部材。
１５． １０．に記載のゴム組成物を用いて成形されたタイヤ用ベルト部材。
１６． １０．に記載のゴム組成物を用いて成形されたタイヤ用カーカス部材。
１７． １０．に記載のゴム組成物を用いて成形されたタイヤ用ショルダー部材。
１８． １０．に記載のゴム組成物を用いて成形されたタイヤ補強層。
１９． ８．に記載のゴム組成物を用いて成形されたタイヤ。
２０． ゴム成分と、不飽和結合を有するフェノール樹脂と、一般式（１）で表されるテトラジン化合物又はその塩と、を含む原料成分を混合する工程（Ｘ）と、
混合された前記原料成分と、加硫剤とを混合する工程（Ｙ）と、
を含み、
前記工程（Ｘ）が、
前記ゴム成分と、前記一般式（１）で表されるテトラジン化合物又はその塩と、前記不飽和結合を有するフェノール樹脂とを、同時に混合する工程（Ｘ－１）、または
前記ゴム成分および前記不飽和結合を有するフェノール樹脂を混合して得られた混合物と、前記一般式（１）で表されるテトラジン化合物又はその塩と、を混合する工程（Ｘ－２）
のいずれかである、ゴム組成物の製造方法。

［式（１）中、Ｘ ^１ 及びＸ ^２ は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。] Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can also be adopted.
Examples of reference forms are added below.
1. a phenolic resin having an unsaturated bond;
a tetrazine compound represented by the general formula (1) or a salt thereof;

[In Formula (1), X ¹ and X ² are the same or different and represent a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
A rubber composition.
2. 1. The phenol resin has at least one structural unit represented by the general formula (2). The rubber composition according to .

[In Formula (2), R ¹ represents a substituent having an unsaturated bond. ]
3. 2. In formula (2), the unsaturated bond is a carbon-carbon unsaturated bond; The rubber composition according to .
4. 1. The phenol resin has at least one structural unit represented by the general formula (3). The rubber composition according to .

[In Formula (3), R ² represents a substituent having an unsaturated bond. R3 represents hydrogen, alkyl group, aryl group, hydroxyl group, ether group, amino group, carboxyl group, ester group, aldehyde group, sulfide group, thiol group, or methylol group ^. ]
5. 4. In formula (3), the unsaturated bond is a carbon-carbon unsaturated bond; The rubber composition according to .
6. 1. The proportion of the peak (4.5 to 6.0 ppm peak) derived from the unsaturated bond in the 1 H-NMR spectrum is 0.5% or more and 20% or less of the total integrated value of the peak (0.2 to 7.5 ppm peak) derived from hydrogen bonded to carbon atoms ^. to 5. The rubber composition according to any one.
7. 1. In formula (1), X ¹ and X ² are heterocyclic groups. to 6. The rubber composition according to any one.
8. 1. The rubber composition contains a rubber component, and contains 0.1 to 30 parts by mass of the phenol resin and 0.01 to 10 parts by mass of the tetrazine compound or a salt thereof per 100 parts by mass of the rubber component. 7. The rubber composition according to any one of items 1 to 7.
9. 8. The rubber component is a diene rubber; The rubber composition according to .
10. 1. used for tire members; to 9. The rubber composition according to any one.
11. 1. to 10. A rubber product molded using the rubber composition according to any one of the above.
12. 10. A tread member for a tire molded using the rubber composition according to 1.
13. 10. A sidewall member for a tire molded using the rubber composition according to 1.
14. 10. A bead member for a tire molded using the rubber composition according to 1.
15. 10. A tire belt member molded using the rubber composition according to 1.
16. 10. A carcass member for a tire molded using the rubber composition according to 1.
17. 10. A shoulder member for a tire molded using the rubber composition according to 1.
18. 10. A tire reinforcing layer molded using the rubber composition according to 1.
19. 8. A tire molded using the rubber composition described in .
20. A step (X) of mixing raw material components containing a rubber component, a phenolic resin having an unsaturated bond, and a tetrazine compound represented by the general formula (1) or a salt thereof;
a step (Y) of mixing the mixed raw material components with a vulcanizing agent;
including
The step (X) is
a step (X-1) of simultaneously mixing the rubber component, the tetrazine compound represented by the general formula (1) or a salt thereof, and the phenolic resin having an unsaturated bond, or
A step (X-2) of mixing a mixture obtained by mixing the rubber component and the phenolic resin having an unsaturated bond with the tetrazine compound represented by the general formula (1) or a salt thereof.
A method for producing a rubber composition.

[In Formula (1), X ¹ and X ² are the same or different and represent a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the content of the present invention is not limited to the examples.

[Synthesis of Phenolic Resin 1]
In a reactor equipped with a stirrer, a reflux condenser and a thermometer, 1000 parts of phenol, 425 parts of cashew nut shell liquid (CNSL, manufactured by Tohoku Kako Co., Ltd.), 20 parts of oxalic acid dihydrate, and 820 parts of a 37% formalin aqueous solution were reacted at 100 ° C. for 3 hours. Thereafter, the temperature was raised to 180° C. over 90 minutes at a vacuum of 40 torr to remove water by distillation, and unreacted phenol was removed by distillation while blowing steam at 180° C. for 30 minutes to obtain phenol resin 1. The number average molecular weight of phenol resin 1 was 1200, and the amount of unsaturated bonds was 6.3 (%).

[Synthesis of Phenolic Resin 3]
Phenolic resin 3 was obtained by the same process except that 600 parts of the cashew nut shell liquid of Example 1, 850 parts of 37% formalin aqueous solution, and 10 parts of 97% sulfuric acid were used instead of oxalic acid dihydrate. Phenol resin 3 had a number average molecular weight of 1,100 and an unsaturated bond content of 1.2 (%).

[Synthesis of Phenolic Resin 4]
Using the same apparatus as in Example 1, 1000 parts of phenol, 10 parts of oxalic acid dihydrate and 650 parts of 37% formalin aqueous solution were reacted at 100° C. for 2 hours. After that, the temperature was raised to 220° C. at a degree of vacuum of 40 torr, and water and unreacted phenol were removed by distillation. After cooling to 150° C., 9 parts of triphenylphosphine and 180 parts of allyl glycidyl ether were added and allowed to react for 2 hours. The number average molecular weight of phenol resin 4 was 1200, and the amount of unsaturated bonds was 7.1 (%).

<Examples, Comparative Examples>
[Preparation of rubber composition]
Using the following materials, rubber compositions were prepared so as to have the compositions shown in Tables 1 and 2.
In Tables 1 and 2, the numerical value indicating the mixing ratio of each component is "parts by weight".
<Material>
Phenolic resin (A)
• Phenolic resin 1: The one obtained by the synthesis described above was used.
Phenolic resin 2: PR-12686, cashew-modified phenolic resin without unsaturated bonds, manufactured by Sumitomo Bakelite Co., Ltd. (number average molecular weight 1100, unsaturated bond content 0%)
• Phenolic resin 3: The one obtained by the synthesis described above was used.
• Phenolic resin 4: The one obtained by the synthesis described above was used.
Tetrazine compound (B)
・Tetrazine compound 1: 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, manufactured by Otsuka Chemical Co., Ltd.
Rubber component (C)
・Rubber component 1: diene rubber, Nipol 1723, oil-extended styrene-butadiene rubber, manufactured by Nippon Zeon Co., Ltd. ・Rubber component 2: diene rubber, natural rubber, RSS3, inorganic filler (D) manufactured by Tochi Co., Ltd.
・Silica: NipsilAQ, manufactured by Tosoh Silica Co., Ltd. ・Carbon black 1: Seast 6, ISAF grade, manufactured by Tokai Carbon Co., Ltd. ・Carbon black 2: Seast 3, HAF grade, manufactured by Tokai Carbon Co., Ltd. Others ・Coupling agent: Si75 (bis (triethoxysilylpropyl) disulfide, manufactured by EVOIC INDUSTRIES)
・Stearic acid: manufactured by Tokyo Chemical Industry Co., Ltd. ・Zinc oxide: manufactured by Tokyo Chemical Industry Co., Ltd. ・HMMM (hexamethoxymethyl melamine): Sumikanol 508, manufactured by Taoka Chemical Co., Ltd. ・Hexamethylenetetramine: manufactured by Tokyo Chemical Industry Co., Ltd. ・Vulcanization accelerator (CZ): N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Tokyo Chemical Industry Co., Ltd. ・Vulcanization accelerator (DPG): 1,3-diphenylguanidine, manufactured by Tokyo Chemical Industry Co., Ltd. ・Vulcanization accelerator (DM): Di-2-benzothiazolyl disulfide, manufactured by Tokyo Chemical Industry Co., Ltd. Sulfur: manufactured by Tokyo Chemical Industry Co., Ltd.

Procedure: Phenolic resin (A), tetrazine compound (B), rubber component (C), inorganic filler (D), vulcanization accelerator and other components other than sulfur were kneaded at 120° C. for 5 minutes using a 250 cc internal Banbury mixer. After kneading, the mixture was discharged out of the mixer and cooled to room temperature. Subsequently, the kneaded product was placed in the same Banbury mixer again, a vulcanization accelerator and sulfur were further added, and the mixture was kneaded for 5 minutes to obtain a rubber composition.

[Preparation of rubber vulcanizates]
By heating at a temperature of 160° C. for 30 minutes, a test piece press-vulcanized to a thickness of 2 mm was evaluated for hardness and 60° C. tan δ in a dynamic viscoelasticity test as described below. The following measurements and evaluations were performed using the rubber vulcanizate thus obtained. Tables 1 and 2 show the results.

<Measurement/Evaluation>
- Hardness Durometer A hardness was evaluated according to JIS K 6253 using a durometer (manufactured by Toyo Seiki Co., Ltd.). Evaluation results are shown in Tables 1 and 2. A larger value indicates better hardness. Note that the units are dimensionless.

・Dynamic viscoelasticity: tan δ at 60°C
A test piece having a width of 10 mm and a length of 40 mm was cut out from a 2 mm thick vulcanized sheet, and a dynamic viscoelasticity tester (ARES G2, manufactured by TA Instruments Co., Ltd.) was used to evaluate tan δ at 60 ° C. at a span of 22 mm, a strain of 2%, and a frequency of 10 Hz. A smaller value indicates a lower hysteresis loss and a better result. Note that the units are dimensionless.

[Measurement of phenolic resin]
The number average molecular weights and unsaturated bond amounts of phenol resins 1 to 4 were measured according to the following procedures. ¹ H-NMR charts are shown in FIGS. 2 to 5, respectively.
Number average molecular weight: Measured by GPC (gel permeation chromatography) using Tosoh TSKgel G1000HXL (1 bottle), G2000HXL (2 bottles), and G3000HXL (1 bottle), using tetrahydrofuran as a solvent, at a column temperature of 40°C, and at a flow rate of 1 ml/min. The number average molecular weight was calculated in terms of polystyrene.
· Unsaturated bond amount: The peak derived from the unsaturated bond in the ¹ H-NMR spectrum (peak of 4.5 to 6.0 ppm) and the peak derived from hydrogen bonded to carbon atoms (peak of 0.2 to 7.5 ppm) were measured, and the ratio (%) of the peak derived from the unsaturated bond to the peak derived from hydrogen bonded to the carbon atom was calculated except for the peak derived from the heavy solvent.
The NMR measurement was performed using JNM-AL300 manufactured by JEOL Ltd. with a deuterated acetone solvent and 64 times of integration.

Claims (19)

a phenolic resin having an unsaturated bond;
a tetrazine compound represented by the general formula (1) or a salt thereof;

[In the formula (1), X ¹ and X ² represent a pyridyl group . ]
A rubber composition. The rubber composition according to claim 1, wherein the phenol resin has at least one structural unit represented by general formula (2).

[In Formula (2), R ¹ represents a substituent having an unsaturated bond. ] The rubber composition according to claim 2, wherein the unsaturated bond in formula (2) is a carbon-carbon unsaturated bond. The rubber composition according to claim 1, wherein the phenol resin has at least one structural unit represented by general formula (3).

[In Formula (3), R ² represents a substituent having an unsaturated bond. ^R3 represents hydrogen, alkyl group, aryl group, hydroxyl group, ether group, amino group, carboxyl group, ester group, aldehyde group, sulfide group, thiol group, or methylol group. ] The rubber composition according to claim 4, wherein the unsaturated bond in formula (3) is a carbon-carbon unsaturated bond. The ratio of the peak (4.5 to 6.0 ppm peak) derived from the unsaturated bond in the ¹ H-NMR spectrum is 0.5% or more and 20% or less of the total integrated value of the peak (0.2 to 7.5 ppm peak) derived from hydrogen bonded to carbon atoms. The rubber composition according to any one of claims 1 to 5. The rubber composition contains a rubber component, and contains 0.1 to 30 parts by mass of the phenol resin and 0.01 to 10 parts by mass of the tetrazine compound or a salt thereof relative to 100 parts by mass of the rubber component. The rubber composition according to any one of claims 1 to 6 . The rubber composition according to claim 7 , wherein the rubber component is a diene rubber. The rubber composition according to any one of claims 1 to 8 , which is used for a tire member. A rubber product molded using the rubber composition according to any one of claims 1 to 9 . A tire tread member molded using the rubber composition according to claim 9 . A tire sidewall member molded using the rubber composition according to claim 9 . A tire bead member molded using the rubber composition according to claim 9 . A tire belt member molded using the rubber composition according to claim 9 . A tire carcass member molded using the rubber composition according to claim 9 . A tire shoulder member molded using the rubber composition according to claim 9 . A tire reinforcing layer molded using the rubber composition according to claim 9 . A tire molded using the rubber composition according to claim 7 . A step (X) of mixing raw material components containing a rubber component, a phenolic resin having an unsaturated bond, and a tetrazine compound represented by the general formula (1) or a salt thereof;
a step (Y) of mixing the mixed raw material components with a vulcanizing agent;
including
The step (X) is
The step (X-1) of simultaneously mixing the rubber component, the tetrazine compound or its salt represented by the general formula (1), and the phenolic resin having an unsaturated bond, or the step (X-2) of mixing the mixture obtained by mixing the rubber component and the phenolic resin having the unsaturated bond with the tetrazine compound or its salt represented by the general formula (1).
A method for producing a rubber composition.

[In the formula (1), X ¹ and X ² represent a pyridyl group . ]

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