JP6808546B2 - Method for manufacturing rubber composition - Google Patents

Description

The present invention relates to a method for producing a rubber composition.

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 method capable of producing a rubber composition having extremely excellent low heat generation by industrially advantageous means.

As a result of diligent studies to solve the above-mentioned problems, the present inventors can solve the above-mentioned problems by kneading a rubber component containing a diene-based rubber and a specific tetrazine-based compound at a predetermined temperature. I found. The present inventors have completed the present invention as a result of further studies based on such findings.

The present invention provides a method for producing a rubber composition shown below.
Item 1.
Rubber components including diene-based rubber, and the following general formula (1):

[In the formula, X ¹ and X ² represent heterocyclic groups that may have substituents. ]
A method for producing a rubber composition for a tire tread or a tire sidewall, which comprises a step (A) of mixing the tetrazine compound represented by (1) or a salt thereof at a discharge temperature of 80 to 210 ° C.
Item 2.
Item 2. The production method according to Item 1, wherein a filler is further present at the time of mixing.
Item 3.
Item 2. The production method according to Item 2, wherein the filler is wet silica and / or carbon black.
Item 4.
Item 3. The production method 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.
The diene rubber is a styrene-butadiene rubber having a weight average molecular weight of 100,000 to 1,000,000 and a bonded styrene content of 15 to 60% by mass, a butadiene rubber having a weight average molecular weight of 100,000 to 1,000,000, and a weight average molecular weight of 200,000 to 200. Item 6. The production method according to any one of Items 1 to 4, wherein the production method is at least one selected from the group consisting of 10,000 natural rubbers and isoprene rubber having a weight average molecular weight of 100,000 to 1.5 million.
Item 6.
The step (A) is a step (A) of producing a modified rubber component by mixing a rubber component containing a diene rubber and a tetrazine compound represented by the general formula (1) or a salt thereof at an discharge temperature of 80 to 210 ° C. Item 2. The production method according to any one of Items 2 to 5, which comprises A-1) and a step (A-2) of mixing the modified rubber component and the filler at a discharge temperature of 100 to 190 ° C.
Item 7.
Item 1 of any one of Items 1 to 6, further comprising a step (B) of adding a vulcanizing agent and a vulcanization accelerator to the mixture obtained in the step (A) and mixing at a discharge temperature of 70 to 130 ° C. The manufacturing method described in.

According to the production method of the present invention, a rubber composition further excellent in low heat generation can be produced extremely easily.

The rubber composition produced by the production method of the present invention can be suitably used for a tire tread or a tire sidewall.

The present invention will be described in detail below.

Method for Producing Rubber Composition In the present invention, a rubber component containing a diene-based rubber and the following general formula (1):

[In the formula, X ¹ and X ² represent heterocyclic groups that may have substituents. ]
For tire tread or tire sidewall, which comprises a step (A) of mixing a tetrazine compound represented by (1) or a salt thereof (hereinafter, also referred to as "tetrazine compound (1)") at a discharge temperature of 80 to 210 ° C. This is a method for producing a rubber composition for tires.

In the present invention, kneading also includes kneading. Further, in the present invention, the "discharge temperature" means, for example, the temperature at which the mixed rubber component or rubber composition is discharged from the device when the mixture is mixed using the following device.

Process (A)
The step (A) is a step of mixing the rubber component and the raw material component containing the tetrazine compound (1), and means that it is a step before blending the vulcanizing agent.

Mixing can be performed using, for example, a device such as a Banbury mixer, a roll, an intensive mixer, a kneader, or a twin-screw extruder.

Rubber component Examples of the rubber component used in the method of the present invention include natural rubber (NR), synthetic diene rubber, diene rubber such as a mixture of natural rubber and synthetic diene rubber, and other non-general rubber. Diene rubber can be mentioned.

Natural rubber includes natural rubber latex, technical rating rubber (TSR), smoked sheet (RSS), backlash, 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 (acrylonitrile-butadiene copolymer rubber) (NBR), and chloroprene rubber (CR). , Ethylene-propylene-diene ternary copolymer rubber (EPDM), styrene-isoprene-styrene ternary block copolymer (SIS), styrene-butadiene-styrene ternary block copolymer (SBS), etc., and these Examples include modified synthetic diene rubber. 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.

In the method of the present invention, it is essential that the rubber component contains diene-based rubber from the viewpoint of low heat generation. As the diene rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), natural rubber, and isoprene rubber are preferable, and styrene-butadiene rubber having a weight average molecular weight of 100,000 to 1,000,000 and a bonded styrene amount of 15 to 60% by mass, More preferably, butadiene rubber having a weight average molecular weight of 100,000 to 1,000,000, natural rubber having a weight average molecular weight of 200,000 to 2,000,000, and isoprene rubber having a weight average molecular weight of 100,000 to 1.5 million. The diene rubber can be used alone or in combination of two or more.

It is preferable that 70 parts by mass or more of the diene rubber is contained in 100 parts by mass of the rubber component, more preferably 75 parts by mass or more, and particularly preferably 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 particularly effective from the viewpoint of low heat generation. 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, and more preferably natural rubber, SBR, BR or a mixture of two or more kinds selected from these. ..

Tetrazine compound (1)
In the method of the present invention, a compound represented by the following general formula (1) or a salt thereof is used.
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-) Triagil) group, 3- (1,2,4-triazyl) group, 5- (1,2,4-triazil) group, 6- (1,2,4-triazil) 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 -Isooxazolyl group, 5-isooxazolyl 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 is, 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 "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 specifically, for example, 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.

In the above step (A), it is preferable that a filler is further present in addition to the rubber component and the tetrazine compound (1) at the time of mixing.

It is preferable to use wet silica and / or carbon black as the filler.

Wet silica In the method of the present invention, the rolling resistance performance can be improved by adding wet silica. The surface of the wet silica may be organically treated with a silane coupling agent, a surfactant, or the like in order to improve the affinity with the rubber component.

The BET specific surface area of the wet 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 point of view, the preferred wet silica is a wet silica having a BET specific surface area in the range of 50 to 250 m ² / g, and more preferably a wet silica having a BET specific surface area of 80 to 230 m ² / g. Particularly preferred is wet silica having a BET specific surface area in the range of 100 to 210 m ² / g.

Commercially available products of such wet 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), Tosoh silica K.K. "Nipsil AQ" (BET specific surface area = 205m ² / g), "Nipseal KQ" (BET specific surface area = 240 m ² / g), Degussa product name "Ultra Jill VN3" (BET specific surface area = 175 m ² / g), Solvay product name "Z1085 Gr" ( 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.

An inorganic filler other than wet silica can be added as the filler within a range that does not impair the effects of the present invention.

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 silica other than the wet silica, alumina such as γ-alumina and α-alumina (Al ₂ O ₃ ); and alumina monohydrate such as boehmite and diaspore (Al ₂ O ₃ · H). ₂ O); Aluminum hydroxide [Al (OH) ₃ ] such as gibsite and 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), calcium hydroxide [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 (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), Silica magnesium calcium (CaMgSiO _4), calcium carbonate (CaCO _3), zirconium oxide _(ZrO 2), zirconium hydroxide _{[ZrO (OH) 2 · nH} 2 O], zirconium carbonate _{[Zr (CO 3) 2]} , various zeolites Examples thereof include crystalline aluminosilicates containing hydrogen, alkali metals or alkaline earth metals for which the charge is corrected. In these inorganic fillers, the surface of the inorganic filler may be organically treated with a silane coupling agent, a surfactant, or the like in order to improve the affinity with 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.

In the step (A), other compounding agents and the like can be further added, if necessary.

Other compounding agents As other compounding agents , compounding agents commonly used in the rubber industry, such as anti-aging agents, anti-ozone agents, emollients, processing aids, waxes, resins, foaming agents, oils, stearic acid, Zinc oxide (ZnO), vulcanization accelerator, vulcanization retarder and the like can be mentioned. 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, when wet silica is blended in the method of the present invention, silane coupling is performed for the purpose of enhancing the reinforcing property of the rubber composition by the wet silica, or for the purpose of enhancing the wear resistance as well as the low heat generation of the rubber composition. It is preferable to mix the agent.

The silane coupling agent that can be used in combination with wet silica 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 and the like 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 method of the present invention, one type of silane coupling agent may be used alone, or two or more types may be used in combination.

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, modified rosin glycerin, and pentaerythritol ester. Terpene-based resins include α-pinene-based resins. , Β-Pinene-based, zipentene-based terpene resins, aromatic-modified terpene resins, terpene phenolic resins, hydrogenated terpene resins and the like.

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.

Examples of the mixing method in the step (A) include a method of mixing a composition containing a rubber component, a tetrazine compound (1), and if necessary, a filler such as wet silica or carbon black. In this mixing method, the entire amount of each component may be mixed at one time, or each component may be divided and added and mixed depending on the purpose such as viscosity adjustment. Further, after mixing the rubber component and the filler if necessary, the tetrazine compound (1) is added and mixed, or after the rubber component and the tetrazine compound (1) are mixed, the filler is added as necessary. It may be mixed. Step (A) may be repeatedly mixed a plurality of times.

The discharge temperature at the time of mixing the rubber composition in the step (A) is not particularly limited as long as it is in the range of 80 to 210 ° C. For example, the discharge temperature of the rubber composition 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 (A) is not particularly limited, and is preferably, for example, 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and further preferably 60 seconds to 7 minutes. preferable.

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

When the wet silica is blended in the step (A), the blending amount is usually 15 to 150 parts by mass, preferably 20 to 120 parts by mass, and more preferably 30 parts by mass with respect to 100 parts by mass of the rubber component. It is ~ 100 parts by mass, more preferably 40 to 90 parts by mass.

In particular, the amount of wet silica blended in order to achieve both steering stability performance and fuel efficiency is usually 30 to 120 parts by mass, preferably 60 to 115 parts by mass with respect to 100 parts by mass of the rubber component. , 70 to 110 parts by mass.

When an inorganic filler other than wet silica is contained, it can be blended within a range that does not impair the effects of the present invention. For example, the total amount of the wet silica and the inorganic filler other than the wet silica in the step (A) is usually 20 to 150 parts by mass, preferably 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component. Yes, more preferably 40 to 90 parts by mass.

When carbon black is blended in the step (A), the blending amount is usually 1 to 150 parts by mass, preferably 2 to 120 parts by mass, and more preferably 4 with respect to 100 parts by mass of the rubber component. ~ 100 parts by mass.

In the step (A), the total amount of the filler may be appropriately adjusted within the range of the above-mentioned blending amount of each component so as to be, for example, 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component. Good. The total amount of the filler may be divided into two or more times and mixed. Further, when blending the filler, a masterbatch polymer previously mixed with the polymer in a wet or dry manner may be used.

Further, as another mixing method in the step (A), there is a step (A-1) of mixing the rubber component and the tetrazine compound (1), and a mixture (modified polymer) obtained in the step (A-1). If necessary, a two-step mixing method including a step (A-2) of mixing with a filler can be mentioned.

In the step (A-1), as a method of mixing the rubber component and the tetradine compound (1), when the rubber component is a solid, a method of mixing the rubber component and the tetrazine compound (1) (solid mixing method). ); When the rubber component is a 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.

In the case of the above solid mixing method, the discharge temperature of the obtained mixture (modified rubber component) is preferably 80 to 210 ° C, more preferably 90 to 160 ° C, and preferably 100 to 150 ° C. More preferred. In the case of the liquid mixing method, the discharge temperature of the obtained mixture (modified rubber component) is preferably 80 to 210 ° C, more preferably 90 to 160 ° C, and further preferably 100 to 150 ° C. preferable.

The mixing time is not particularly limited. For example, in the case of the solid mixing method, it is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and 60 seconds to 7 minutes. Is even more preferable. 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 mixture (modified rubber component) can be recovered under reduced pressure.

The blending amount of the tetrazine compound (1) in the step (A-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.

The modified rubber component obtained in the step (A-1) may be transferred to the step (A-2) without being discharged. In that case, for example, the upper limit of the temperature of the mixture of the rubber component and the tetrazine compound (1) is preferably 80 to 210 ° C., more preferably 90 to 160 ° C., still more preferably 100 to 150 ° C., and the above mixing time. You just have to mix.

By the step (A-1) of mixing 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 rubber component.

In the step (A-2), the discharge temperature at the time of mixing the modified rubber component obtained in the step (A-1) with the filler, if necessary, is preferably in the range of 100 to 190 ° C. For example, the discharge temperature of the mixture is more preferably 130 to 180 ° C, even more preferably 140 to 170 ° C.

The mixing time in the step (A-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.

When the wet silica is blended in the step (A-2), the blending amount is not particularly limited, and for example, with respect to 100 parts by mass of the mixture (modified rubber component) obtained in the step (A-1). It is usually 15 to 150 parts by mass, preferably 20 to 120 parts by mass, more preferably 30 to 100 parts by mass, and further preferably 40 to 90 parts by mass.

In particular, the amount of wet silica blended in order to achieve both steering stability performance and fuel efficiency is usually 30 to 120 parts by mass, preferably 60 to 115 parts by mass with respect to 100 parts by mass of the rubber component. , 70 to 110 parts by mass.

When an inorganic filler other than wet silica is contained in the step (A-2), it can be blended within a range that does not impair the effects of the present invention. For example, the total amount of the wet silica and the inorganic filler other than the wet silica is usually 20 to 150 parts by mass with respect to 100 parts by mass of the mixture (modified rubber component) obtained in the step (A-1). , It is preferably 30 to 120 parts by mass, and more preferably 40 to 90 parts by mass.

In particular, when the silane coupling agent is blended together with the wet silica, the blending amount of the silane coupling agent is preferably 2 to 20 parts by mass and particularly preferably 3 to 15 parts by mass with respect to 100 parts by mass of the wet silica. preferable. If it is 2 parts by mass or more, the effect of low heat generation can be more preferably exhibited in the obtained rubber composition, and if it is 20 parts by mass or less, the cost of the obtained rubber composition is reduced and it is economical. Is improved.

When carbon black is blended in the step (A-2), the blending amount is usually 1 to 150 parts by mass with respect to 100 parts by mass of the mixture (modified rubber component) obtained in the step (A-1). Yes, preferably 2 to 120 parts by mass, more preferably 4 to 100 parts by mass.

In the step (A-2), the total amount of the filler is, for example, 20 to 150 parts by mass with respect to 100 parts by mass of the mixture (modified rubber component) obtained in the step (A-1). It may be appropriately adjusted within the range of the above-mentioned blending amount of each component.

In the step (A), a rubber composition in which the double bond portion of the rubber component (diene-based rubber) reacts with the tetrazine compound (1) to form a modified rubber component, and in some cases, the filler is preferably dispersed. Obtainable.

The method of the present invention may include the above step (A), and other steps are not particularly limited. For example, after the above step (A), a step (B) of adding a vulcanizing agent or the like to the mixture obtained in the step (A) and mixing the mixture can be performed.

Process (B)
The step (B) is a step of mixing the mixture obtained in the step (A) and the vulcanizing agent.

In the step (B), a vulcanization accelerator, zinc oxide and the like can be further added, if necessary.

Examples of the vulcanizing agent include thiuram compounds such as sulfur and tetramethylthiuram disulfide, and peroxide compounds such as dicumylperoxide.

Examples of the vulcanization accelerator include guanidine-based, thiuram-based, dithiocarbamate-based, thiazole-based, and sulfenamide-based compounds. Further, as a vulcanization accelerating aid, zinc oxide, zinc stearate, stearic acid and the like can be blended.

The discharge temperature in the step (B) is preferably in the range of 70 to 130 ° C. The discharge temperature is more preferably 80 to 120 ° C., and even more preferably 90 to 120 ° C.

The mixing 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 (A) to the step (B), the temperature of the rubber composition after the completion of the previous step (A) is lowered to be equal to or lower than the discharge temperature of the step (B), and then the next step (B) is performed. It is preferable to proceed to.

In the method of the present invention, various compounding agents such as anti-aging agents, which are usually blended in the rubber composition, can be added in the step (A) or the step (B), if necessary.

By the above steps (A) and (B), a rubber composition containing a modified rubber component obtained by treating a diene-based rubber in the rubber component with a tetrazine compound (1), and optionally a filler, is produced. be able to.

The rubber composition obtained by the method of the present invention includes a rubber component, a tetrazine compound (1), a composition containing a filler in some cases, and a diene-based rubber in the rubber component and a tetrazine compound (1). ), And optionally both a rubber composition containing a filler.

Applications of the rubber composition obtained by the process of the application the invention of a rubber composition, for example, such as a rubber portion of the tire and the like. Among them, preferable applications are a tire tread portion, a tire sidewall portion, a tire bead area portion, a tire belt portion, a tire carcass portion and a tire shoulder portion, and a tire tread portion or a tire sidewall portion is particularly preferable.

The rubber composition is formed as a tire tread or a tire sidewall by being mixed using an apparatus such as the above-mentioned Bunbury mixer and then extruded and processed in an extrusion step.

Examples of tires produced by using the rubber composition obtained by the method 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 are not particularly limited and can be appropriately selected according to the purpose.

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 (1b) 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)

Examples 1 to 20: Production of Modified Rubber Components Each rubber component and tetrazine compound shown in Tables 1 and 2 were mixed in their proportions (parts by mass) using a Banbury mixer. After the temperature of the mixture reached the discharge temperature listed in each table, the modified rubber component was discharged.

Examples 21-60
Using each of the modified rubber components produced in Examples 1 to 20, each component shown in steps (A-2) of Tables 3 to 6 was mixed in a proportion (part by mass) using a Banbury mixer. After the temperature of the mixture reached the discharge temperature of the step (A-2) in each table, the mixture was discharged and cured until the temperature of the mixture became 80 ° C. or lower. Then, each component described in the step (B) of each table is added at the ratio (part by mass) and mixed, and after the temperature of the mixture reaches the discharge temperature of the step (B) described in each table, the mixture is discharged. Each rubber composition was produced.

Examples 61-69
Each component described in step (A) of Table 7 was mixed at the ratio (part by mass), and mixed using a Banbury mixer. After the temperature of the mixture reached the discharge temperature of the step (A) shown in the table, the mixture was discharged and cured until the temperature of the mixture became 80 ° C. or lower. Then, each component described in the step (B) is added at the ratio (part by mass) and mixed, and after the temperature of the mixture reaches the discharge temperature of the step (B) described in the table, the rubber is discharged and each rubber is discharged. The composition was produced.

Examples 70-73
After mixing each component described in the step (A-1) of Table 8 at the ratio (part by mass) and kneading at the mixing temperature and mixing time of the step (A-1) shown in the table using a Banbury mixer. , Each component described in step (A-2) was charged, mixed until the temperature of the mixture reached the discharge temperature of step (A-2) described in the table, and discharged. After curing until the temperature of the mixture becomes 70 ° C. or lower, each component described in the step (B) is added at the ratio (part by mass) and mixed, and the temperature of the mixture is the step (B) shown in the table. After reaching the discharge temperature of, each rubber composition was produced by discharging.

Low heat generation (tan δ index) test For the rubber compositions (test compositions) prepared in Examples 21 to 73, a viscoelasticity measuring device (manufactured by Metravib) was used, and the temperature was 40 ° C., the dynamic strain was 5%, and the frequency was 15 Hz. Tan δ was measured with.

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 3-8.

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

[Explanation of symbols in the table]
The raw materials used in the examples (in the table) are shown below.
* 1: 3,6-bis (2-pyridyl) -1,2,4,5-tetrazine, manufactured by Tokyo Chemical Industry Co., Ltd. * 2: 3,6-bis (3-pyridyl) -1,2,4 5-Tetrazine (compound produced in Production Example 1)
* 3: 3,6-bis (4-pyridyl) -1,2,4,5-tetrazine, manufactured by Tokyo Chemical Industry Co., Ltd. * 4: manufactured by PetroChina Dushanzi Petrochemical Company, product name "RC2557S"
* 5: Product name "Nipol NS116R" manufactured by Zeon Corporation
* 6: Asahi Kasei Chemicals Co., Ltd., product name "F3430"
* 7: Asahi Kasei Chemicals Co., Ltd., product name "Asuprene Y031"
* 8: Made by Shenha Chemical Industrial Co., ltd., Product name "SBR1739"
* 9: Product name "BR9000" manufactured by Sinopec Qilu Petrochemical Co., Ltd.
* 10: Product name "TSR20" manufactured by GUANGKEN RUBBER
* 11: Product name "RSS3" manufactured by Chuka Kokusai Co., Ltd.
* 12: Made by Nippon Zeon Corporation, product name "IR2200"
* 13: Modified S-SBR produced in Example 1
* 14: Modified S-SBR produced in Example 2
* 15: Modified S-SBR produced in Example 3
* 16: Modified S-SBR produced in Example 4
* 17: Modified S-SBR / BR produced in Example 5
* 18: Modified S-SBR produced in Example 6
* 19: Modified S-SBR / BR produced in Example 7.
* 20: Modified S-SBR / BR produced in Example 8
* 21: Modified S-SBR / BR produced in Example 9
* 22: Modified S-SBR / BR produced in Example 10
* 23: Modified S-SBR / BR produced in Example 11
* 24: Modified S-SBR / BR produced in Example 12
* 25: Modified S-SBR / BR produced in Example 13
* 26: Modified E-SBR produced in Example 14
* 27: Modified NR / BR produced in Example 15
* 28: Modified NR / BR produced in Example 16
* 29: Modified S-SBR produced in Example 17
* 30: Modified NR produced in Example 18
* 31: Modified IR produced in Example 19
* 32: Modified BR produced in Example 20
* 33: Product name "HD165MP" manufactured by Quechen Silicon Chemical Co., Ltd.
* 34: Product name "Si69" manufactured by Evonik Industries AG
* 35: Made by Cabot, product name "N234"
* 36: Made by Cabot, product name "N375"
* 37: Product name "6-PPD" manufactured by Kemai Chemical Co., Ltd.
* 38: Made by Dalian Zinc Oxide Co., Ltd. * 39: Made by Sichuan Tianyu Grease Chemical Co., Ltd. * 40: Made by Rhein Chemie Rheinau GmbH, trade name "Antilux 111"
* 41: Product name "Vivatec 700" manufactured by Hansen & Rosenthal
* 42: Made by Shanghai Jinghai Chemical Co., Ltd. * 43: Made by Kemai Chemical Co., Ltd., Product name "DPG"
* 44: Product name "CBS" manufactured by Kemai Chemical Co., Ltd.
* 45: Product name "TBBS" manufactured by Kemai Chemical Co., Ltd.

By using the method of the present invention, a rubber composition having extremely excellent low heat generation can be industrially advantageously produced. By using the rubber composition, a tread portion (tire tread) and a sidewall portion of pneumatic tires of various automobiles can be manufactured.

Claims (8)

Rubber components including diene-based rubber, and the following general formula (1):

[In the formula, X ¹ and X ² indicate a pyridyl group which may have a substituent. ]
A method for producing a rubber composition for a tire tread or a tire sidewall, which comprises a step (A) of mixing the tetrazine compound represented by (1) or a salt thereof at a discharge temperature of 80 to 210 ° C. The substituents are 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, a nitro group, an alkyl group and a hydroxyalkyl group. The production method according to claim 1, wherein the production method is at least one selected from the group consisting of 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 production method according to claim 1 or 2 , wherein an additional filler is present at the time of mixing. The production method according to claim 3 , wherein the filler is wet silica and / or carbon black. The production method according to any one of claims 1 to 4 , wherein 70 parts by mass or more of the diene-based rubber is contained in 100 parts by mass of the rubber component. The diene rubber is a styrene-butadiene rubber having a weight average molecular weight of 100,000 to 1,000,000 and a bonded styrene content of 15 to 60% by mass, a butadiene rubber having a weight average molecular weight of 100,000 to 1,000,000, and a weight average molecular weight of 200,000 to 200. The production method according to any one of claims 1 to 5 , wherein the production method is at least one selected from the group consisting of 10,000 natural rubbers and isoprene rubber having a weight average molecular weight of 100,000 to 1.5 million. The step (A) is a step (A) of producing a modified rubber component by mixing a rubber component containing a diene rubber and a tetrazine compound represented by the general formula (1) or a salt thereof at an discharge temperature of 80 to 210 ° C. The production method according to any one of claims 2 to 6 , further comprising A-1) and a step (A-2) of mixing the modified rubber component and the filler at a discharge temperature of 100 to 190 ° C. Further, any one of claims 1 to 7 , further comprising a step (B) of adding a vulcanizing agent and a vulcanization accelerator to the mixture obtained in the step (A) and mixing at a discharge temperature of 70 to 130 ° C. The manufacturing method described in the section.