JP6808545B2 - Rubber composition and tires - Google Patents

Description

The present invention relates to rubber compositions and tires.

In recent years, due to consideration for the environment, carbon dioxide emission regulations have become stricter worldwide, and the demand for fuel efficiency of automobiles has increased significantly. The efficiency of the drive system such as the engine and the transmission system contributes greatly to the fuel efficiency, but the rolling resistance of the tire is also greatly involved, and it is important to reduce the rolling resistance to reduce the fuel efficiency of the automobile. ..

As a method for reducing the rolling resistance of a tire, it is known to apply a rubber composition having low heat generation to the tire. Examples of such a low heat-generating rubber composition include (1) a rubber composition containing a functionalized polymer having an enhanced affinity with carbon black as a filler and silica (Patent Document 1); (2). ) A rubber composition containing a diene elastomer, an inorganic filler as a reinforcing filler, an alkoxysilane polysulfide as a coupling agent, 1,2-dihydropyridine, and a guanidine derivative (Patent Document 2); (3) Rubber component, aminopyridine derivative. And rubber compositions containing an inorganic filler (Patent Document 3); (4) rubber compositions containing a terminally modified polymer and an inorganic filler (Patent Documents 4 and 5) and the like.

According to the inventions described in Patent Documents 1 to 5, the heat generation of the rubber composition can be lowered by increasing the affinity between the filler and the rubber component, and as a result, hysteresis loss (rolling) can be achieved. A tire with low resistance) can be obtained.

However, even if the rubber compositions of Patent Documents 1 to 5 are used, the improvement of low heat generation is insufficient.

The demand for fuel efficiency of automobiles is increasing, and the development of tires with extremely low heat generation is eagerly desired.

Japanese Unexamined Patent Publication No. 2003-514079 Special Table 2003-523472 Japanese Unexamined Patent Publication No. 2013-108004 Japanese Unexamined Patent Publication No. 2000-169631 JP-A-2005-220323

An object of the present invention is to provide a rubber composition capable of exhibiting low heat generation.

Another object of the present invention is to provide a tire having excellent low heat generation.

As a result of diligent studies to solve the above problems, the present inventors reduced the content of butyl rubber in the rubber component and mixed the rubber component with a specific amount of the tetrazine compound to obtain the above. I found that I could solve the problem of. The present inventors have completed the present invention as a result of further studies based on such findings.
The present invention provides the rubber composition, tire, etc. shown below.
Item 1.
Rubber component and the following general formula (1):

[In the formula, X ¹ and X ² represent heterocyclic groups that may have substituents. ]
A rubber composition containing a tetrazine compound represented by (1) or a salt thereof.
Butyl-based rubber is contained in a proportion of less than 30 parts by mass in 100 parts by mass of the rubber component.
A rubber composition containing 0.1 to 10 parts by mass of the tetrazine compound or a salt thereof with respect to 100 parts by mass of the rubber component.
Item 2.
Item 2. The rubber composition according to Item 1, further comprising an inorganic filler and / or carbon black.
Item 3.
Item 2. The rubber composition according to Item 2, wherein the total amount of the inorganic filler and / or carbon black is 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component.
Item 4.
Item 2. The rubber composition according to any one of Items 1 to 3, wherein 70 parts by mass or more of diene-based rubber is contained in 100 parts by mass of the rubber component.
Item 5.
Item 4. The rubber composition according to Item 4, wherein the diene rubber is at least one selected from the group consisting of natural rubber, isoprene rubber, styrene-butadiene copolymer rubber, and butadiene rubber.
Item 6.
The rubber composition according to any one of Items 2 to 5, wherein the inorganic filler is silica.
Item 7.
Item 6. The rubber composition according to Item 6, wherein the silica is a wet silica having a BET specific surface area (m ² / g) in the range of 40 to 350.
Item 8.
Item 2. The rubber composition according to any one of Items 2 to 7, wherein the amount of the inorganic filler blended is 20 to 150 parts by mass with respect to 100 parts by mass of the rubber composition.
Item 9.
Item 2. The rubber composition according to any one of Items 2 to 8, wherein the amount of carbon black blended is 2 to 150 parts by mass with respect to 100 parts by mass of the rubber composition.
Item 10.
Item 6. The rubber composition according to any one of Items 1 to 9 used for the tread portion.
Item 11.
A tire tread produced by using the rubber composition according to any one of Items 1 to 9.
Item 12.
A tire sidewall produced by using the rubber composition according to any one of Items 1 to 9.

According to the present invention, it is possible to provide a rubber composition capable of exhibiting low heat generation by combining a specific rubber component with a tetrazine compound represented by the general formula (1) or a salt thereof.

Further, by producing a tire using the rubber composition of the present invention, the rolling resistance of the tire can be reduced and the heat generation of the tire can be reduced, so that a fuel-efficient tire can be provided.

The present invention will be described in detail below.

1. 1. Rubber Composition In the present invention, the rubber component and the following general formula (1):

[In the formula, X ¹ and X ² represent heterocyclic groups that may have substituents. ]
A rubber composition containing a tetrazine compound represented by (hereinafter, also referred to as "tetrazine compound (1)") or a salt thereof.
Butyl-based rubber is contained in a proportion of less than 30 parts by mass in 100 parts by mass of the rubber component.
A rubber composition containing 0.1 to 10 parts by mass of the tetrazine compound or a salt thereof with respect to 100 parts by mass of the rubber component.

Rubber component The rubber component to be blended in the rubber composition of the present invention is not particularly limited, and is, for example, a diene-based rubber such as natural rubber (NR), synthetic diene-based rubber, and a mixture of natural rubber and synthetic diene-based rubber. Examples include rubber and other non-diene rubbers including butyl rubbers.

Natural rubber includes natural rubber latex, technical rating rubber (TSR), smoked sheet (RSS), rattling, Tochu-derived natural rubber, Guayur-derived natural rubber, Russian dandelion-derived natural rubber, and plant-based fermented rubber. In addition, modified natural rubber such as epoxidized natural rubber, methacrylic acid modified natural rubber, and styrene modified natural rubber can be mentioned.

Examples of synthetic diene rubbers include styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), nitrile rubber (NBR), chloroprene rubber (CR), and ethylene-propylene-diene ternary products. Examples thereof include polymer rubber (EPDM), styrene-isoprene-styrene ternary block copolymer (SIS), styrene-butadiene-styrene ternary block copolymer (SBS), and modified synthetic diene rubbers thereof. Examples of the modified synthetic diene rubber include diene rubber produced by a modification method such as main chain modification, one-terminal modification, and two-terminal modification. Here, the modified functional group of the modified synthetic diene rubber includes one or more functional groups containing heteroatoms such as an epoxy group, an amino group, an alkoxy group, a hydroxyl group, an alkoxysilyl group, a polyether group and a carboxyl group. Things can be mentioned. The ratio of cis / trans / vinyl in the diene portion is not particularly limited, and any ratio can be preferably used. The average molecular weight and molecular weight distribution of the diene rubber are not particularly limited, and an average molecular weight of 5 to 3 million and a molecular weight distribution of 1.5 to 15 are preferable. The method for producing the synthetic diene-based rubber is also not particularly limited, and examples thereof include those synthesized by emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, cationic polymerization and the like.

As the non-diene rubber, known rubbers can be widely used.

Examples of butyl rubber include butyl rubber (IIR) and halogenated butyl rubber. Examples of the halogenated butyl rubber include brominated butyl rubber (BIIR), chlorinated butyl rubber (CIIR) and the like. The butyl rubber is a copolymer of isobutylene and a small amount of isoprene rubber, and contains a double bond of 3 mol% or less, but is not included in the diene rubber in the present specification.

From the viewpoint of low heat generation, it is preferable that the proportion of butyl rubber contained in the rubber component is small. Specifically, in the present invention, it is essential that butyl rubber is contained in a proportion of less than 30 parts by mass in 100 parts by mass of the rubber component. When the content of the butyl rubber is 30 parts by mass or more, the effect of the present invention cannot be exhibited. In the present invention, the amount of butyl rubber is preferably less than 10 parts by mass, more preferably less than 5 parts by mass, and particularly preferably not contained at all in 100 parts by mass of the rubber component.

The rubber component contains a diene-based rubber from the viewpoint of low heat generation. Specifically, 70 parts by mass or more of the diene-based rubber is preferably contained in 100 parts by mass of the rubber component, and 75 parts by mass or more is contained. It is more preferable that the mixture is blended in an amount of 80 to 100 parts by mass.

Further, at the glass transition point of the diene rubber, those in the range of −120 ° C. to −15 ° C. are effective from the viewpoint of achieving both wear resistance and braking characteristics. The rubber composition of the present invention is preferably a diene-based rubber in which 50% by mass or more of the diene-based rubber has a glass transition point in the range of −70 ° C. to −20 ° C.

The rubber component can be used alone or in combination of two or more. Among them, the preferable rubber component is natural rubber, IR, SBR, BR, or a mixture of two or more kinds selected from these. The blending ratio thereof is not particularly limited, and it is preferable to mix SBR, BR or a mixture thereof in 100 parts by mass of the rubber component in a ratio of 70 to 100 parts by mass, and to mix in 75 to 100 parts by mass. It is more preferable to do so. When blending a mixture of SBR and BR, the total amount of SBR and BR is preferably in the above range. Further, the SBR at this time is 50 to 100 parts by mass, and the BR is preferably in the range of 0 to 50 parts by mass.

Tetrazine compound (1)
The rubber composition of the present invention contains a compound represented by the following general formula (1) or a salt thereof.
General formula 1:

[In the formula, X ¹ and X ² represent heterocyclic groups that may have substituents. ]

In the present specification, the "heterocyclic group" is not particularly limited, and for example, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazinyl group, 2-pyrimidyl group, 4-pyrimidyl group, and the like. 5-pyrimidyl group, 3-pyridadyl group, 4-pyridadyl group, 4- (1,2,3-triazyl) group, 5- (1,2,3-triazyl) group, 2- (1,3,5- Triasyl) group, 3- (1,2,4-triazyl) group, 5- (1,2,4-triazyl) group, 6- (1,2,4-triazyl) group, 2-quinolyl group, 3- Quinoline group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6- Isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalyl group, 3-quinoxalyl group, 5-quinoxalyl group, 6-quinoxalyl group, 7-quinoxalyl group, 8-quinoxalyl group, 3-cinnolyl group, 4- Synolyl group, 5-Synolinyl group, 6-Synolyl group, 7-Synolyl group, 8-Synolinyl group, 2-Kynazolyl group, 4-Kynazolyl group, 5-Kynazolyl group, 6-Kynazolyl group, 7-Kynazolyl group, 8- Kinazolyl group, 1-phthalazyl group, 4-phthalazyl group, 5-phthalazyl group, 6-phthalazyl group, 7-phthalazyl group, 8-phthalazyl group, 1-tetrahydroquinoline group, 2-tetrahydroquinoline group, 3-tetrahydro Quinoline group, 4-tetrahydroquinoline group, 5-tetrahydroquinoline group, 6-tetrahydroquinoline group, 7-tetrahydroquinoline group, 8-tetrahydroquinoline group, 1-pyrrolyl group, 2-pyrrolill group, 3 -Pyrrolyl group, 2-Frill group, 3-Frill group, 2-Thienyl group, 3-Thienyl group, 1-Imidazolyl group, 2-Imidazolyl group, 4-Imidazolyl group, 5-Imidazolyl group, 1-Pyrazolyl group, 3 -Pyrazolyl group, 4-pyrazolyl group, 5-pyrazolyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isooxazolyl group, 4 -Isoxazolyl group, 5-isoxazolyl group, 3-isothiazolyl group, 4-isothiazolyl group, 5-isothiazolyl group, 4- (1,2,3-thiadiazolyl) group, 5- (1,2,3-thiadiazolyl) group, 3- (1,2,5-thiazol) group, 2- (1,3,4-thiazol) Le) group, 4- (1,2,3-oxadiazolyl) group, 5- (1,2,3-oxadiazolyl) group, 3- (1,2,4-oxadiazolyl) group, 5- (1,2, 4- (1,2,5-oxadiazolyl) group, 3- (1,2,5-oxadiazolyl) group, 2- (1,3,4-oxadiazolyl) group, 1- (1,2,3-triazolyl) group, 4- (1, 2,3-Triazolyl) group, 5- (1,2,3-triazolyl) group, 1- (1,2,4-triazolyl) group, 3- (1,2,4-triazolyl) group, 5- ( 1,2,4-triazolyl) group, 1-tetrazolyl group, 5-tetrazolyl group, 1-indrill, 2-indrill group, 3-indrill group, 4-indrill group, 5-indrill group, 6-indrill group, 7 -Indrill group, 1-isoindrill group, 2-isoindrill group, 3-isoindrill group, 4-isoindrill group, 5-isoindrill group, 6-isoindrill group, 7-isoindrill group, 1-benzoimidazolyl group, 2-benzoimidazolyl group, 4 -Benomidazolyl group, 5-benzoimidazolyl group, 6-benzoimidazolyl group, 7-benzoimidazolyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1 -Isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofunyl group, 2-benzothienyl group, 3-benzothienyl group, 4-benzothienyl group, 5-benzothienyl group, 6-benzothienyl group, 7-benzothienyl group, 2-benzoxazolyl group, 4-benzoxazolyl group, 5-benzoxa Zoryl group, 6-benzoxazolyl group, 7-benzoxazolyl group, 2-benzothiazolyl group, 4-benzothiazolyl group, 5-benzothiazolyl group, 6-benzothiazolyl group, 7-benzothiazolyl group, 1-indazolyl group, 3-Indazolyl group, 4-Indazolyl group, 5-Indazolyl group, 6-Indazolyl group, 7-Indazolyl group, 2-Molholyl group, 3-Morphoryl group, 4-Morphoryl group, 1-Piperazyl group, 2-Piperazyl group, 1-piperidyl group, 2-piperidyl group, 3-piperidyl group, 4-piperidyl group, 2-tetrahydropyranyl group, 3-tetrahydropyranyl group, 4-tetrahydropyranyl group, 2-tetrahydrothiopyranyl Group, 3-tetrahydrothiopyranyl group, 4-tetrahydrothiopyranyl group, 1-pyrrolidyl group, 2-pyrrolidyl group, 3-pyrrolidyl group, 2-tetrahydrofuranyl group, 3-tetrahydrofuranyl group, 2-tetrahydrothienyl group , 3-Tetrahydrofuranyl group and the like. Among them, the preferred heterocyclic group is a pyridyl group, a furanyl group, a thienyl group, a pyrimidyl group or a pyrazil group, and more preferably a pyridyl group.

The heterocyclic group may have one or more substituents at substituent positions. The substituent is not particularly limited, and for example, a halogen atom, an amino group, an aminoalkyl group, an alkoxycarbonyl group, an acyl group, an acyloxy group, an amide group, a carboxyl group, a carboxyalkyl group, a formyl group, a nitrile group, and a nitro group. Examples thereof include a group, an alkyl group, a hydroxyalkyl group, a hydroxyl group, an alkoxy group, an aryl group, an aryloxy group, a heterocyclic group, a thiol group, an alkylthio group and an arylthio group. The substituent may preferably have 1 to 5, more preferably 1 to 3.

In the present specification, examples of the "halogen atom" include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and preferably a chlorine atom, a bromine atom, and an iodine atom.

In the present specification, the "amino group" includes not only the amino group represented by -NH ₂ , but also, for example, a methylamino group, an ethylamino group, an n-propylamino group, an isopropylamino group and an n-butylamino group. , Isobutylamino group, s-butylamino group, t-butylamino group, 1-ethylpropylamino group, n-pentylamino group, neopentylamino group, n-hexylamino group, isohexylamino group, 3-methylpentyl A linear or branched monoalkylamino group having 1 to 6 carbon atoms (particularly 1 to 4 carbon atoms) such as an amino group; 1 to 6 carbon atoms (particularly) such as a dimethylamino group, an ethylmethylamino group and a diethylamino group. Substituted amino groups such as a dialkylamino group having two linear or branched alkyl groups having 1 to 4 carbon atoms are also included.

In the present specification, the "aminoalkyl group" is not particularly limited, and for example, an aminoalkyl group such as an aminomethyl group, a 2-aminoethyl group, or a 3-aminopropyl group (preferably having an amino group and having 1 carbon number). ~ 6 linear or branched alkyl groups).

In the present specification, the "alkoxycarbonyl group" is not particularly limited, and examples thereof include a methoxycarbonyl group and an ethoxycarbonyl group.

In the present specification, the "acyl group" is not particularly limited, and examples thereof include a linear or branched alkylcarbonyl group having 1 to 4 carbon atoms such as an acetyl group, a propionyl group, and a pivaloyl group.

In the present specification, the "acyloxy group" is not particularly limited, and examples thereof include an acetyloxy group, a propionyloxy group, and an n-butyryloxy group.

In the present specification, the "amide group" is not particularly limited, and for example, a carboxylic acid amide group such as an acetamido group or a benzamide group; a thioamide group such as a thioacetamide group or a thiobenzamide group; an N-methylacetamide group or N. N-substituted amide groups such as −benzylacetamide groups; and the like.

In the present specification, the "carboxyalkyl group" is not particularly limited, and for example, a carboxymethyl group, a carboxyethyl group, a carboxy-n-propyl group, a carboxy-n-butyl group, a carboxy-n-butyl group, and a carboxy group. Examples thereof include a carboxy-alkyl group such as an -n-hexyl group (preferably an alkyl group having a carboxy group and having 1 to 6 carbon atoms).

In the present specification, the "hydroxyalkyl group" is not particularly limited, and for example, a hydroxy-alkyl group such as a hydroxymethyl group, a hydroxyethyl group, a hydroxy-n-propyl group, or a hydroxy-n-butyl group (preferably). Alkyl groups having 1 to 6 carbon atoms having a hydroxy group) can be mentioned.

In the present specification, the "alkyl group" is not particularly limited, and examples thereof include linear, branched or cyclic alkyl groups, and specific examples thereof include methyl group, ethyl group and n-propyl. Group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, 1-ethylpropyl group, n-pentyl group, neopentyl group, n-hexyl group, isohexyl group, 3-methylpentyl group Linear or branched alkyl groups having 1 to 6 carbon atoms (particularly 1 to 4 carbon atoms); cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, etc. Examples thereof include a cyclic alkyl group having 8 (particularly 3 to 6 carbon atoms).

In the present specification, the "hydroxyalkyl group" is not particularly limited, and for example, a hydroxy-alkyl group such as a hydroxymethyl group, a hydroxyethyl group, a hydroxy-n-propyl group, or a hydroxy-n-butyl group (preferably). Alkyl groups having 1 to 6 carbon atoms having a hydroxy group) can be mentioned.

In the present specification, the "alkoxy group" is not particularly limited, and examples thereof include linear, branched or cyclic alkoxy groups, and specific examples thereof include methoxy, ethoxy group and n-propoxy group. , Isopropoxy group, n-butoxy group, t-butoxy group, n-pentyloxy group, neopentyloxy group, n-hexyloxy group having 1 to 6 carbon atoms (particularly 1 to 4 carbon atoms) linear or Branched alkoxy groups; cyclic groups having 3 to 8 carbon atoms (particularly 3 to 6 carbon atoms) such as cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, cycloheptyloxy group and cyclooctyloxy group. Alkoxy groups and the like can be mentioned.

In the present specification, the "aryl group" is not particularly limited, and examples thereof include a phenyl group, a biphenyl group, a naphthyl group, a dihydroindenyl group, and a 9H-fluorenyl group.

In the present specification, the "aryloxy group" is not particularly limited, and examples thereof include a phenoxy group, a biphenyloxy group, and a naphthoxy group.

In the present specification, the "alkylthio group" is not particularly limited, and examples thereof include linear, branched or cyclic alkylthio groups, and specific examples thereof include methylthio group, ethylthio group and n-propylthio. Group, isopropylthio group, n-butylthio group, isobutylthio group, s-butylthio group, t-butylthio group, 1-ethylpropylthio group, n-pentylthio group, neopentylthio group, n-hexylthio group, isohexylthio Linear or branched alkylthio groups having 1 to 6 carbon atoms (particularly 1 to 4 carbon atoms) such as groups and 3-methylpentylthio groups; cyclopropylthio group, cyclobutylthio group, cyclopentylthio group, cyclohexylthio Examples thereof include a cyclic alkylthio group having 3 to 8 carbon atoms (particularly 3 to 6 carbon atoms) such as a group, a cycloheptylthio group and a cyclooctylthio group.

In the present specification, the "arylthio group" is not particularly limited, and examples thereof include a phenylthio group, a biphenylthio group, and a naphthylthio group.

The "salt" of the tetrazine compound represented by the general formula (1) is not particularly limited and includes all kinds of salts. Examples of such salts 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; magnesium salts and calcium. Alkaline earth metal salts such as salts; quaternary ammonium salts such as dimethylammonium and triethylammonium can be mentioned.

In the preferred tetradine compound (1), X ¹ and X ² have the same or different pyridyl group which may have a substituent, a furanyl group which may have a substituent, and a substituent. A compound which is a thienyl group which may have a substituent, a pyrazolyl group which may have a substituent, a pyrimidyl group which may have a substituent, or a pyrazil group which may have a substituent.

A more preferable tetradine compound (1) is a 2-pyridyl group in which X ¹ and X ² are the same or different and may have a substituent, a 3-pyridyl group which may have a substituent, and a substitution. It may have a 4-pyridyl group which may have a group, a 2-furanyl group which may have a substituent, a thienyl group which may have a substituent, and 1- which may have a substituent. A compound which is a pyrazolyl group, a 2-pyrimidyl group which may have a substituent, or a 2-pyrazyl group which may have a substituent, and specifically, a compound which may have a substituent. A good 2-pyridyl group, a 3-pyridyl group which may have a substituent, a 4-pyridyl group which may have a substituent, or a 2-furanyl group which may have a substituent. Compounds are particularly preferred.

As a specific example of the tetrazine compound (1),
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-bis (2-furanyl) -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 (2-pyrimidinyl) -1,2,4,5-tetrazine,
Examples thereof include 3,6-bis (2-pyrazyl) -1,2,4,5-tetrazine.

Among them, the preferred tetrazine compound (1) is 3,6-bis (2-pyridyl) -1,2,4,5-tetrazine and 3,6-bis (3-pyridyl) -1,2,4,5- Tetrazine, 3,6-bis (2-furanyl) -1,2,4,5-tetrazine, and 3,6- (4-pyridyl) -1,2,4,5-tetrazine, more preferred tetrazine compounds. (1) is 3,6-bis (2-pyridyl) -1,2,4,5-tetrazine, 3,6-bis (3-pyridyl) -1,2,4,5-tetrazine, and 3, 6-Bis (4-pyridyl) -1,2,4,5-tetrazine.

The blending amount of the tetrazine compound (1) is usually 0.1 to 10 parts by mass, preferably 0.25 to 5 parts by mass, and more preferably 0.25 to 5 parts by mass with respect to 100 parts by mass of the rubber component in the rubber composition. It is 0.5 to 2 parts by mass.

When the tetrazine compound (1) is a powder, its volume average diameter is not particularly limited. From the viewpoint of low exothermic development, the volume average diameter is preferably 300 μm or less, more preferably 150 μm or less, and particularly preferably 75 μm or less.

The volume mean diameter can be obtained as a particle diameter corresponding to 50% of the integrated distribution curve from the volume reference particle size distribution by using a particle size distribution measuring device such as a laser light diffraction method.

Further, from the viewpoint of handleability during handling and reduction of ignitability or explosive risk, powder may be surface-treated with oil, resin, stearic acid, etc., or powder may be treated with calcium carbonate, silica, etc. You may use it by mixing with the filler of.

The rubber composition of the present invention preferably further contains an inorganic filler and / or carbon black in addition to the rubber component and the tetrazine compound (1).

The blending amount of the inorganic filler is usually 20 to 150 parts by mass, preferably 30 to 120 parts by mass, and more preferably 40 to 90 parts by mass with respect to 100 parts by mass of the rubber component.

The blending amount of carbon black is usually 2 to 150 parts by mass, preferably 4 to 120 parts by mass, and more preferably 6 to 100 parts by mass with respect to 100 parts by mass of the rubber component.

In the rubber composition of the present invention, the inorganic filler and / or carbon black is the total amount of both components, for example, 20 to 150 parts by mass, preferably 40 to 130 parts by mass with respect to 100 parts by mass of the rubber component. It may be appropriately adjusted within the range of the above-mentioned blending amount of each component so as to be parts by mass, more preferably 45 to 100 parts by mass.

When the total amount of the inorganic filler and / or carbon black is 20 parts by mass or more, it is preferable from the viewpoint of improving the reinforcing property of the rubber composition, and when it is 150 parts by mass or less, it is preferable from the viewpoint of reducing rolling resistance. .. When blending the inorganic filler and / or carbon black, a masterbatch polymer previously mixed with the polymer in a wet or dry manner may be used.

Inorganic filler The inorganic filler is not particularly limited as long as it is an inorganic compound usually used in the rubber industry. Examples of the inorganic compounds that can be used include alumina such as silica, γ-alumina and α-alumina (Al ₂ O ₃ ); alumina monohydrate such as boehmite and diaspore (Al ₂ O ₃・ H ₂ O); gibsite. , Aluminum hydroxide [Al (OH) ₃ ] such as bayarite; Aluminum carbonate [Al ₂ (CO ₃ ) ₂ ], Magnesium hydroxide [Mg (OH) ₂ ], Magnesium oxide (MgO), Magnesium carbonate (MgCO ₃₎ ), talc _{(3MgO · 4SiO 2 · H 2} O), attapulgite _{(5MgO · 8SiO 2 · 9H 2} O), titanium white _(TiO 2), titanium black _{(TiO 2n-1),} calcium oxide (CaO), hydroxide calcium [Ca _(OH) 2], magnesium aluminum oxide _{(MgO · Al 2 O 3)} , clay _{(Al 2 O 3 · 2SiO 2} ), kaolin _{(Al 2 O 3 · 2SiO 2} · 2H 2 O), pyrophyllite _{(Al 2 O 3 · 4SiO 2} · H 2 O), bentonite _{(Al 2 O 3 · 4SiO 2} · 2H 2 O), aluminum silicate _{(Al 2 SiO 5, Al 4} · 3SiO 4 · 5H 2 O , etc.), Magnesium silicate (Mg ₂ SiO ₄ , MgSiO ₃ etc.), Calcium silicate (Ca ₂ · SiO ₄ etc.), Aluminum silicate calcium (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), Calcium magnesium silicate (CaMgSiO ₄ etc.) ), Calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO (OH) ₂ · nH ₂ O], zirconium carbonate [Zr (CO ₃ ) ₂ ], charge correction like various zeolites Examples thereof include crystalline aluminosilicates containing hydrogen, alkali metals or alkaline earth metals. In these inorganic fillers, the surface of the inorganic filler may be organically treated in order to improve the affinity with the rubber component.

Silica is preferably added because it can impart rubber strength. Any commercially available silica can be used. Among them, preferred silica is wet silica, dry silica, or colloidal silica, and more preferably wet silica. In order to improve the affinity of these silicas with the rubber component, the surface of the inorganic filler may be organically treated.

Among them, silica is preferable as the inorganic filler from the viewpoint of braking characteristics, and the BET specific surface area of silica is not particularly limited, and examples thereof include a range of 40 to 350 m ² / g. Silica having a BET specific surface area in this range has an advantage that both rubber reinforcing properties and dispersibility in rubber components can be achieved at the same time. The BET specific surface area is measured according to ISO 5794/1.

From this viewpoint, the preferred silica is silica having a BET specific surface area in the range of 50 to 250 m ² / g, more preferably silica having a BET specific surface area of 80 to 230 m ² / g, and particularly preferably. , BET specific surface area is silica in the range of 100 to 210 m ² / g. Further, these silicas having different BET specific surface areas may be used in combination.

Commercially available products of such silica include trade names "HD165MP" (BET specific surface area = 165m ² / g) and "HD115MP" (BET specific surface area = 115m ² / g) manufactured by Quechen Silicon Chemical Co., Ltd. "HD200MP" (BET specific surface area = 200m ² / g), "HD250MP" (BET specific surface area = 250m ² / g), trade name "Nipseal AQ" manufactured by Toso Silica Co., Ltd. (BET specific surface area = 205m ² / g) ), "Nipseal KQ" (BET specific surface area = 240m ² / g), Degussa product name "Ultra Jill VN3" (BET specific surface area = 175m ² / g), Solbay product name "Z1085Gr" (BET) Specific surface area = 90 m ² / g), "Z Premium 200MP" (BET specific surface area = 215 m ² / g), "Z HRS 1200 MP" (BET specific surface area = 200 m ² / g) and the like.

The amount of silica blended is usually 20 to 120 parts by mass, preferably 30 to 100 parts by mass, and more preferably 40 to 90 parts by mass with respect to 100 parts by mass of the rubber component.

Carbon black The carbon black is not particularly limited, and examples thereof include commercially available carbon black and carbon-Silica dual phase filler.

Specifically, carbon black includes, for example, high, medium or low structure SAF, ISAF, IISAF, N110, N134, N220, N234, N330, N339, N375, N550, HAF, FEF, GPF, SRF grade carbon. Black and the like can be mentioned. Among them, preferable carbon blacks are SAF, ISAF, IISAF, N134, N234, N330, N339, N375, HAF, or FEF grade carbon black.

The DBP absorption of carbon black is not particularly limited, preferably 60~200cm ³ / 100g, more preferably 70~180cm ³ / 100g or more, particularly preferably 80~160cm ³ / 100g.

The nitrogen adsorption specific surface area of carbon black (measured according to N2SA, JIS K 6217-2: 2001) is preferably 30 to 200 m ² / g, more preferably 40 to 180 m ² / g, and particularly preferably. It is 50 to 160 m ² / g.

By blending the tetrazine compound (1) in the rubber composition containing carbon black, the dispersibility of carbon black can be significantly improved, and the low heat generation property of the rubber composition can be significantly improved.

Other Blending Agents In addition to the above tetrazine compound (1) and the inorganic filler and / or carbon black, the rubber composition of the present invention contains a compounding agent commonly used in the rubber industry, such as sulfur. A sulfurizing agent can be blended. The rubber composition of the present invention may further contain other formulations such as anti-aging agents, antioxidants, softeners, processing aids, waxes, resins, foaming agents, oils, stearic acid, zinc oxide (ZnO). , Vulcanization accelerator, vulcanization retarder and the like may be blended. These compounding agents can be appropriately selected and compounded within a range that does not impair the object of the present invention. Commercially available products can be preferably used as these compounding agents.

Further, in a rubber composition containing an inorganic filler such as silica, silane coupling is used for the purpose of enhancing the reinforcing property of the rubber composition by silica, or for the purpose of enhancing the wear resistance as well as the low heat generation of the rubber composition. The agent may be blended.

The silane coupling agent that can be used in combination with the inorganic filler is not particularly limited, and a commercially available product can be preferably used. Examples of such a silane coupling agent include sulfide-based, polysulfide-based, thioester-based, thiol-based, olefin-based, epoxy-based, amino-based, and alkyl-based silane coupling agents.

Examples of the sulfide-based silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-methyldimethoxysilylpropyl) tetrasulfide, and bis ( 2-Triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-methyldimethoxysilylpropyl) disulfide, bis (2-triethoxysilylpropyl) Ethyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-methyldimethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide Sulfide, bis (3-monoethoxydimethylsilylpropyl) tetrasulfide, bis (3-monoethoxydimethylsilylpropyl) trisulfide, bis (3-monoethoxydimethylsilylpropyl) disulfide, bis (3-monomethoxydimethylsilylpropyl) Tetrasulfide, bis (3-monomethoxydimethylsilylpropyl) trisulfide, bis (3-monomethoxydimethylsilylpropyl) disulfide, bis (2-monoethoxydimethylsilylethyl) tetrasulfide, bis (2-monoethoxydimethylsilylethyl) ) Trisulfide, bis (2-monoethoxydimethylsilylethyl) disulfide and the like. Of these, bis (3-triethoxysilylpropyl) tetrasulfide is particularly preferable.

Examples of the thioester-based silane coupling agent include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, and 3-lauroylthiopropyltriethoxysilane. , 2-Hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-Octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2 − Decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane, etc. can be mentioned.

Examples of the thiol-based silane coupling agent include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane.

Examples of the olefin-based silane coupling agent include dimethoxymethylvinylsilane, vinyltrimethoxysilane, dimethylethoxyvinylsilane, diethoxymethylvinylsilane, triethoxyvinylsilane, vinyltris (2-methoxyethoxy) silane, allyltrimethoxysilane, and allyltri. Ethoxysilane, p-styryltrimethoxysilane, 3- (methoxydimethoxydimethylsilyl) propyl acrylate, 3- (trimethoxysilyl) propyl acrylate, 3- [dimethoxy (methyl) silyl] propyl methacrylate, 3- (trimethoxysilyl) Examples thereof include propyl methacrylate, 3- [dimethoxy (methyl) silyl] propyl methacrylate, 3- (triethoxysilyl) propyl methacrylate, 3- [tris (trimethylsiloxy) silyl] propyl methacrylate and the like.

Examples of the epoxy-based silane coupling agent include 3-glycidyloxypropyl (dimethoxy) methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy (3-glycidyloxypropyl) methylsilane, and triethoxy (3-glycidyloxypropyl) silane. , 2- (3,4-epylcyclohexyl) ethyltrimethoxysilane and the like. Of these, 3-glycidyloxypropyltrimethoxysilane is preferable.

Examples of the amino-based silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and 3-aminopropyl. Trimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl)- Examples thereof include 2-aminoethyl-3-aminopropyltrimethoxysilane. Of these, 3-aminopropyltriethoxysilane is preferable.

Examples of the alkyl-based silane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, and isobutyltriethoxy. Examples thereof include silane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane and the like. Of these, methyltriethoxysilane is preferred.

Among these silane coupling agents, bis (3-triethoxysilylpropyl) tetrasulfide can be particularly preferably used.

In the present invention, one type of silane coupling agent may be used alone, or two or more types may be used in combination.

The blending amount of the silane coupling agent of the rubber composition of the present invention is preferably 0.1 to 20 parts by mass, and particularly preferably 3 to 15 parts by mass with respect to 100 parts by mass of the inorganic filler. If it is 0.1 part by mass or more, the effect of low heat generation of the rubber composition can be more preferably exhibited, and if it is 20 parts by mass or less, the cost of the rubber composition is reduced and the economic efficiency is improved. Because it does.

Further, in the case where the braking characteristic is particularly important, a resin or the like may be added. Specific examples thereof include natural resins such as rosin-based resins and terpene-based resins, petroleum-based resins, phenol-based resins, coal-based resins, and xylene-based resins. Examples of the rosin-based resin include gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionate rosin, polymerized rosin, or modified rosin glycerin and pentaerythritol ester. Examples of the terpene-based resin include α-pinene-based, β-pinene-based, and dipentene-based terpene resins, aromatic-modified terpene resins, terpene phenol resins, and hydrogenated terpene resins.

In cases where processability is important, mineral oil, petrolatum, paraffin wax, petroleum resin, fatty acid, fatty acid ester, fatty alcohol, metal soap, fatty acid amide, phenol resin, polyethylene, polybutene, peptizer, etc. A regenerating agent, an organosiloxane, or the like can be added.

Uses of Rubber Compositions Uses of the rubber composition of the present invention are tire treads or sidewalls.

Method for Producing Rubber Composition The method for producing the rubber composition of the present invention is not particularly limited. The method for producing a rubber composition of the present invention includes, for example, a step (I) of kneading a rubber component, a tetrazine compound (1), and, if necessary, a raw material component containing an inorganic filler and / or carbon black, and a step ( The step (II) of kneading the mixture obtained in I) and the vulcanizing agent is included.

Step (I)
Step (I) is a step of kneading the rubber component, the tetrazine compound (1), and if necessary, a raw material component containing an inorganic filler and / or carbon black, and is a step before blending the vulcanizing agent. It means that. In this step (I), the tetrazine compound (1) reacts with the double bond of the diene rubber.

In the step (I), the above-mentioned other compounding agents and the like can be further added, if necessary.

Examples of the kneading method in the step (I) include a method of kneading a composition containing a rubber component, a tetrazine compound (1), an inorganic filler and / or carbon black. In this kneading method, the entire amount of each component may be kneaded at one time, or each component may be divided and kneaded according to the purpose such as viscosity adjustment. Further, the rubber component and the inorganic filler and / or carbon black are kneaded and then the tetrazine compound (1) is added and kneaded, or the rubber component and the tetrazine compound (1) are kneaded and then the inorganic filler and / or carbon black are kneaded. / Or carbon black may be added and kneaded. Step (I) may be repeatedly kneaded a plurality of times.

As the temperature at which the rubber composition is mixed in the step (I), the amount of heat required for the tetrazine compound (1) to react with the diene-based rubber may be given. For example, the upper limit of the temperature of the rubber composition is 120 to 120. The temperature is preferably 190 ° C, more preferably 130 to 175 ° C, and even more preferably 140 to 170 ° C.

The mixing time in the step (I) is not particularly limited, and is preferably, for example, 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and further preferably 2 minutes to 7 minutes. preferable.

In the step (I), the blending amount of the tetrazine compound (1) is not particularly limited, and is, for example, 0.1 to 10 parts by mass, preferably 0.25 to 5 parts by mass with respect to 100 parts by mass of the rubber component. It is by mass, more preferably 0.5 to 2 parts by mass.

The blending amount of the inorganic filler in the step (I) is usually 20 to 150 parts by mass, preferably 30 to 120 parts by mass, and more preferably 40 to 90 parts by mass with respect to 100 parts by mass of the rubber component. Is.

The blending amount of carbon black in the step (I) is usually 2 to 150 parts by mass, preferably 4 to 120 parts by mass, and more preferably 6 to 100 parts by mass with respect to 100 parts by mass of the rubber component. is there.

In the step (I), the inorganic filler and / or carbon black is a total amount of both components, for example, 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component. It may be adjusted appropriately within the range of the amount.

Further, as another kneading method in the step (I), the step (I-1) of kneading the rubber component and the tetrazine compound (1), and the mixture and the inorganic filler obtained in the step (I-1) and the inorganic filler / Or a two-step kneading method including a step (I-2) of kneading with carbon black can be mentioned.

In the step (I-1), as a method of kneading the rubber component and the tetrazine compound (1), when the rubber component is a solid, the method of kneading the rubber component and the tetrazine compound (1) (kneading method). When the rubber component is liquid (liquid), a method of mixing the solution or emulsion (suspension) of the rubber component with the tetrazine compound (1) (liquid mixing method) and the like can be mentioned.

As the kneading temperature, the amount of heat required for the tetrazine compound (1) to react with the diene rubber may be given. For example, in the case of the above kneading method, the upper limit of the temperature of the rubber component is 80 to 190 ° C. Is more preferable, 90 to 160 ° C. is more preferable, and 100 to 150 ° C. is even more preferable. In the case of the liquid mixing method, the upper limit of the temperature of the rubber component is preferably 80 to 170 ° C., more preferably 90 to 160 ° C., and even more preferably 100 to 150 ° C.

The mixing time or kneading time is, for example, preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 60 seconds to 7 minutes in the case of the kneading method. .. In the case of the liquid mixing method, it is preferably 10 seconds to 60 minutes, more preferably 30 seconds to 40 minutes, and even more preferably 60 seconds to 30 minutes. After the mixing reaction by the liquid mixing method, for example, the solvent in the mixture can be blown off (removed) and the solid rubber composition can be recovered under reduced pressure.

The blending amount of the tetrazine compound (1) in the step (I-1) is not particularly limited, and is usually 0.1 to 10 parts by mass, preferably 0.25 parts by mass, based on 100 parts by mass of the rubber component. It is ~ 5 parts by mass, more preferably 0.5 to 2 parts by mass.

By the step (I-1) of kneading the rubber component and the tetrazine compound (1), the double bond of the diene rubber in the rubber component reacts with the tetrazine compound (1) to form a modified polymer.

In the step (I-2), the temperature at which the mixture (modified polymer) obtained in the step (I-1) and the inorganic filler and / or carbon black are mixed is not particularly limited, and for example, the mixture. The upper limit of the temperature is preferably 120 to 190 ° C, more preferably 130 to 175 ° C, and even more preferably 140 to 170 ° C.

The mixing time in the step (I-2) is not particularly limited, and is preferably, for example, 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and 2 minutes to 7 minutes. Is even more preferable.

The blending amount of the inorganic filler in the step (I-2) is usually 20 to 150 parts by mass, preferably 30 parts by mass, based on 100 parts by mass of the mixture (modified polymer) obtained in the step (I-1). It is ~ 120 parts by mass, more preferably 40 to 90 parts by mass.

The blending amount of carbon black in the step (I-2) is usually 2 to 150 parts by mass, preferably 4 to 150 parts by mass, based on 100 parts by mass of the mixture (modified polymer) obtained in the step (I-1). It is 120 parts by mass, more preferably 6 to 100 parts by mass.

In the step (I-2), the inorganic filler and / or carbon black is the total amount of both components, for example, with respect to 100 parts by mass of the mixture (modified polymer) obtained in the step (I-1). , Usually, it may be appropriately adjusted within the range of the above-mentioned blending amount of each component so as to be 20 to 150 parts by mass.

Step (II)
The step (II) is a step of mixing the mixture obtained in the step (I) and the vulcanizing agent, and means the final step of kneading.

In the step (II), a vulcanization accelerator or the like can be further added, if necessary.

The mixing temperature in the step (II) is not particularly limited, and is, for example, preferably 60 to 140 ° C., more preferably 80 to 120 ° C., and even more preferably 90 to 120 ° C.

The mixing (or kneading) time is not particularly limited, and is preferably, for example, 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 60 seconds to 5 minutes. ..

When proceeding from the step (I) to the step (II), it is preferable to lower the temperature by 30 ° C. or more from the temperature after the completion of the step in the previous step before proceeding to the next step (II).

In the method for producing a rubber composition of the present invention, various compounding agents such as stearic acid, zinc oxide, a vulcanization accelerator, and an antiaging agent, which are usually blended in the rubber composition, are used in step (I), if necessary. Alternatively, it can be added in step (II).

A rubber composition containing a modified polymer obtained by treating a diene-based rubber in a rubber component with a tetrazine compound (1) by the above steps (I) and (II), and an inorganic filler and / or carbon black. Can manufacture things.

The modified polymer formed in step (I) or (II-1) is produced by proceeding with a reaction as shown in the following reaction formulas -1 to 4.

[In the formula, X ¹ and X ² are the same as described above. ]

In the reaction formula-1, the reverse electron request type Aza-Diels-Alder reaction between the double bond site of the diene rubber represented by the formula (A-1) and the tetrazine compound (1) is carried out by the formula (B-1). ) Is formed. The -N = N-part in this bicyclo ring structure is easily denitrified and has a six-membered ring structure represented by the formulas (C-1), (C-2) or (C-3). It is formed, but further oxidized by oxygen in the air to produce a modified polymer having a six-membered ring structure represented by the formula (2-1).

[In the formula, X ¹ and X ² are the same as described above. ]

In the reaction formula-2, similarly to the reaction formula-1, from the double bond site of the diene rubber represented by the formula (A-2) and the tetrazine compound (1), the formula (B-2) or ( After forming the bicyclo ring structure represented by B-2') and then the six-membered ring structure represented by the formulas (C-4) to (C-9), the formula (2-2) or (2-3) A modified polymer having a six-membered ring structure represented by) is produced.

[In the formula, X ¹ and X ² are the same as described above. R represents an alkyl group or a halogen atom. ]

In the reaction formula-3, the reverse electron-required Aza-Diels-Alder reaction between the double bond site of the diene rubber represented by the formula (A-3) and the tetrazine compound (1) is carried out by the formula (B-3). ) Or (B-3') is formed, and then denitrification is performed to obtain a modified polymer having a six-membered ring structure represented by the formulas (2-4) to (2-7). Manufactured. When R on the double bond site of the diene-based rubber represented by the formula (A-3) is a halogen atom, the halogen atom may be eliminated. In that case, the formula is formed by an oxidation reaction. A modified polymer having a six-membered ring structure represented by (2-1) is produced.

[In the formula, X ¹ , X ² and R are the same as described above. ]

In the reaction formula-4, similarly to the reaction of the reaction formula-3, the reaction between the double bond site of the diene rubber represented by the formula (A-4) and the tetrazine compound (1) causes the formula (B-). 4) Or, after forming the bicyclo ring structure represented by (B-4'), a modified polymer having a six-membered ring structure represented by the formulas (2-8) to (2-11) is produced. Ru.

As described above, the produced modified polymer has a heteroatom such as a nitrogen atom, and this heteroatom strongly interacts with the inorganic filler (particularly silica) and carbon black, and thus the rubber composition. It is possible to enhance the dispersibility of the inside and impart high low heat generation.

The rubber composition of the present invention is a modified polymer produced by reacting a rubber component, particularly a double bond of a diene rubber with a tetrazine compound (1), preferably the following formulas (2-1) to (1). It includes a rubber composition containing a modified polymer having at least one selected from the compound structures represented by 2-11).

[In the formula, X ¹ , X ² and R are the same as described above. ]

3. 3. Tire The tire of the present invention is a tire manufactured by using the rubber composition of the present invention.

Examples of the tire of the present invention include tires such as pneumatic tires (radial tires, bias tires, etc.) and solid tires.

The use of the tire is not particularly limited, and examples thereof include a passenger car tire, a high load tire, a motorcycle (motorcycle) tire, a studless tire, and the like, and among them, the tire can be preferably used for a passenger car tire.

The shape, structure, size and material of the tire of the present invention are not particularly limited and may be appropriately selected depending on the intended purpose.

In the tire of the present invention, the rubber composition is used particularly for at least one member selected from a tread portion, a sidewall portion, a bead area portion, a belt portion, a carcass portion and a shoulder portion.

Among them, one of the preferred embodiments is to form the tire tread portion or sidewall portion of the pneumatic tire with the rubber composition.

The tire tread portion is a portion having a tread pattern and in direct contact with the road surface, and is a tire outer skin portion that protects the carcass and prevents wear and trauma, and is a cap tread and / or a cap tread that constitutes the ground contact portion of the tire. The base tread that is placed inside the tire.

The sidewall portion is, for example, a portion of a pneumatic radial tire from the lower side of the shoulder portion to the bead portion, which protects the carcass and is the portion that bends most when traveling.

The bead area portion is a portion that has the role of fixing both ends of the carcass cord and at the same time fixing the tire to the rim. A bead is a structure in which high carbon steel is bundled.

The belt portion is a reinforcing band stretched in the circumferential direction between the tread having a radial structure and the carcass. The carcass is strongly tightened like a tub to increase the rigidity of the tread.

The carcass portion is a portion of the cord layer forming the skeleton of the tire, and plays a role of withstanding the load received by the tire, the impact, and the filling air pressure.

The shoulder part is the shoulder part of the tire and plays a role of protecting the carcass.

The tire of the present invention can be manufactured according to a method known so far in the field of tires.

Further, as the gas to be filled in the tire, normal or air with adjusted oxygen partial pressure; an inert gas such as nitrogen, argon or helium can be used.

Hereinafter, the present invention will be specifically described with reference to Production Examples and Examples. However, the examples are merely examples, and the present invention is not limited to the examples.

Production Example 1: Production of 3,6-bis (3-pyridyl) -1,2,4,5-tetrazine (1a) In a 200 mL four-necked flask, add 24 g (0.23 mol) of 3-cyanopyridine and water. 15 g (1.3 eq) of hydrazine and 48 mL of methanol were added, and the mixture was stirred at room temperature. Next, 3.6 g (15% by weight) of sulfur was added to this mixture, a reflux tube was attached, and the mixture was heated and stirred overnight at an outside temperature of 70 ° C. The reaction was ice-cooled, the crystals were filtered and washed with a small amount of cold methanol. The crude crystals were dried under reduced pressure to obtain 19 g of orange dihydrotetrazine crude crystals.

17.8 g of the obtained crude crystals were dissolved in 178 g (40 equivalents) of acetic acid, and sulfur was removed by filtration. A dihydrotetrazine acetic acid solution and 178 mL of distilled water were added to a 1 L four-necked eggplant flask, and the mixture was stirred under ice-cooling. 15.5 g (3 equivalents) of sodium nitrite was dissolved in 35 mL of distilled water, added dropwise to the reaction solution over about 1 hour, and the mixture was stirred overnight at room temperature. The precipitated crystals were filtered, and the crystals were neutralized with 10% layered water to obtain crude crystals. The crude crystals were purified on a silica gel column (ethyl acetate) to obtain 8.4 g (purple red, acicular crystals) of the title tetrazine compound (1a).
Melting point: 200 ° C,
^{1 1} H-NMR (300 MHz, CDCl ₃ , δ ppm):
7.59 (ddd, J = 0.9, 5.1, 7.8 Hz, 2H), 8.89-8.96 (m, 4H), 9.88 (dd, J = 0.9, 2) .4Hz, 2H)

Production Example 2: Production of 3,6-diphenyl-1,2,4,5-tetrazine (Comparative Compound (1)) 120 g (1.16 mol) of benzonitrile and 76 g of hydrated hydrazine (1.16 mol) in a 500 mL four-necked flask. 1.3 equivalents) and 348 mL of methanol were added and stirred at room temperature. Next, 10 g (8.6% by weight) of sulfur was added to this mixture, a reflux tube was attached, and the mixture was heated and stirred overnight at an outside temperature of 70 ° C. The resulting reaction was ice-cooled, the crystals were filtered and washed with a small amount of cold methanol. The obtained crude crystals were dissolved in 2.5 L of warm methanol, the insoluble material was filtered, and then the solvent of the filtrate was distilled off. The obtained crude crystals were dried under reduced pressure to obtain 48 g of yellow dihydrotetrazine crude crystals.

4.8 g of crude crystals, 48 mL of acetic acid, and 48 mL of distilled water were added to a 300 mL four-necked eggplant flask, and the mixture was stirred under ice-cooling. 4.2 g (3 eq) of sodium nitrite was dissolved in 48 mL of distilled water. The reaction mixture was added dropwise to the reaction solution over about 1 hour, and then the mixture was stirred overnight at room temperature. 100 mL of distilled water was added to the reaction solution, and the crystals were filtered. The obtained crude crystals were washed with 10 mL of acetic acid and filtered to obtain 3.9 g (reddish purple, acicular crystals) of the title comparative compound (1).
Melting point: 166 ° C,
^{1 1} H-NMR (300 MHz, CDCl ₃ , δ ppm):
7.58-7.68 (m, 6H), 8.64-8.69 (m, 4H)

Production Example 3: Production of 1,4-dihydro-3,6-diphenyl-1,2,4,5-tetrazine (comparative compound (2)) 120 g (1.16 mol) of benzonitrile in a 500 mL four-necked flask. , 76 g (1.3 eq) of hydrated hydrazine, and 348 mL of methanol were added, and the mixture was stirred at room temperature. Next, 10 g (8.6% by weight) of sulfur was added to this mixture, a reflux tube was attached, and the mixture was heated and stirred overnight at an outside temperature of 70 ° C. The resulting reaction was ice-cooled, the crystals were filtered and washed with a small amount of cold methanol. The obtained crude crystals were dissolved in 2.5 L of warm methanol, the insoluble material was filtered, and then the solvent of the filtrate was distilled off. The obtained crude crystals were dried under reduced pressure to obtain 48 g (yellow crude crystals) of the title comparative compound (2).
Melting point: 199 ° C,
^{1 1} H-NMR (300 MHz, CDCl ₃ , δ ppm):
7.40 to 7.47 (m, 3H), 7.80 to 7.83 (m, 2H), 9.07 (s, 1H)

Examples 1 to 5 and Comparative Examples 1 to 4
Each component shown in steps (I) of Tables 1 and 2 below was mixed at that ratio (part by mass), and kneaded with a Banbury mixer for 5 minutes while adjusting the rotation speed so that the maximum temperature of the mixture was 160 ° C. .. After curing until the temperature of the mixture becomes 80 ° C. or lower, each component shown in steps (II) of Tables 1 and 2 is added at the ratio (part by mass), and the maximum temperature of the mixture becomes 110 ° C. or lower. Each rubber composition was produced by kneading while adjusting the above.

For the rubber compositions (test compositions) produced in the low heat generating (tan δ index) test Examples 1 to 5 and Comparative Examples 1 to 4, a viscoelasticity measuring device (manufactured by Metravib) was used, and the temperature was 40 ° C. Tan δ was measured at a dynamic strain of 5% and a frequency of 15 Hz.

A rubber composition (reference) was prepared by the same formulation and the same manufacturing method as in each Example and Comparative Example except that the tetrazine compound (1) was not added, and the low heat build-up index was calculated based on the following formula. did.

The larger the value of the low heat generation index, the lower the heat generation and the smaller the hysteresis loss. The low heat generation of the vulcanized rubber composition of each reference is 100.

The results are shown in Tables 1 and 2.

Formula: Low exothermic index = {(reference tan δ) / (test composition tan δ)} × 100

[Explanation of symbols in the table]
The raw materials used in Table 1 or 2 are shown below.
* 1: Made by Nippon Butyl Co., Ltd., trade name "Butyl 268"
* 2: Made by Asahi Kasei Corporation, product name "Toughden 2000R"
* 3: Product name "NS116R" manufactured by Zeon Corporation
* 4: Product name "BR150B" manufactured by Ube Industries, Ltd.
* 5: Product name "Nipsil (brand AQ)" manufactured by Toso Silica Co., Ltd.
* 6: Made by Evonik Industries AG, product name "Si69"
* 7: Product name "Seast 3" manufactured by Tokai Carbon Co., Ltd.
* 8: Product name "Antage 6C" manufactured by Kawaguchi Chemical Industry Co., Ltd.
* 9: Zinc oxide brand "1 type" manufactured by Sakai Chemical Industry Co., Ltd.
* 10: Made by Sichuan Tianyu Grease Chemical Co., Ltd. * 11: Made by JX Nikko Nisseki Energy Co., Ltd., Product name "X-140 (aroma oil)"
* 12: Product name "HT254" manufactured by Stratktor
* 13: 3,6-bis (3-pyridyl) -1,2,4,5-tetrazine (compound produced in Production Example 1)
* 14: 3,6-bis (2-pyridyl) -1,2,4,5-tetrazine, manufactured by Tokyo Chemical Industry Co., Ltd. * 15: 3,6-bis (4-pyridyl) -1,2,4 5-Tetrazine, manufactured by Tokyo Chemical Industry Co., Ltd. * 16: 3,6-diphenyl-1,2,4,5-Tetrazine (compound produced in Production Example 2)
* 17: 1,4-dihydro-3,6-diphenyl-1,2,4,5-tetrazine (compound produced in Production Example 3)
* 18: Product name "HK200-5" manufactured by Hosoi Chemical Industry Co., Ltd.
* 19: Product name "Noxeller D" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
* 20: Product name "Noxeller CZ-G" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.

Since the rubber composition of the present invention is excellent in low heat generation, the tread portion (tire tread) of pneumatic tires of various automobiles can be manufactured by using the rubber composition.

Claims (6)

Rubber component and the following general formula (1):

[In the formula, X ¹ and X ² indicate a pyridyl group which may have a substituent. ]
A rubber composition containing a tetrazine compound represented by (1) or a salt thereof.
Diene-based rubber is contained in a proportion of 70 parts by mass or more and butyl-based rubber is contained in a proportion of less than 30 parts by mass in 100 parts by mass of the rubber component.
A rubber composition containing 0.1 to 10 parts by mass of the tetrazine compound or a salt thereof with respect to 100 parts by mass of the rubber component. The rubber composition according to claim 1, further comprising an inorganic filler and / or carbon black. The rubber composition according to claim 2, wherein the total amount of the inorganic filler and / or carbon black is 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component. The rubber composition according to any one of claims 1 to 3, which is used for a tread portion. A tire tread produced by using the rubber composition according to any one of claims 1 to 3. A sidewall for a tire produced by using the rubber composition according to any one of claims 1 to 3.