JP2018154743A - Viscosity-reducing agent, rubber having viscosity reduced, and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a viscosity-reducing agent capable of reducing the viscosity of rubber.SOLUTION: The viscosity-reducing agent contains a tetrazine compound represented by the general formula (1)or a salt thereof. [In the formula, Xand Xare identical or different, and each represents a hydrogen atom, alkyl group, alkylthio group, aralkyl group, aryl group, arylthio group, heterocyclic group or amino group. Each of these groups may have one or more substituents.]SELECTED DRAWING: None

Description

  The present invention relates to a viscosity reducing agent, a reduced viscosity rubber, and a method for producing the same.

  Conventionally, tire treads are required to have wear resistance, and it is known that natural rubber is the main raw material as a raw rubber in order to improve wear resistance. However, since natural rubber has a higher molecular weight than synthetic rubber and is inferior in processability, it is difficult to uniformly disperse reinforcing agents such as carbon black and silica that are conventionally blended into tire treads.

  Therefore, after kneading natural rubber together with a predetermined amount of a kneading accelerator under predetermined conditions and performing a kneading step for appropriately reducing the molecular weight of the raw rubber, compounding agents such as a reinforcing agent and a softening agent are further added under predetermined conditions. A method of performing a kneading step of adding and kneading is employed (Patent Documents 1 and 2).

  According to the inventions described in these Patent Documents 1 and 2, thiophenol or disulfide is used as a kneading accelerator, and the viscosity of rubber is adjusted by adjusting the conditions of the kneading process and the conditions of the kneading process. Can be reduced, thereby improving workability.

  However, even if the methods of Patent Documents 1 and 2 are used, the effect of improving workability due to viscosity reduction is insufficient.

JP 2000-186154 A Special table 2006-199723 gazette

  An object of the present invention is to provide a viscosity reducing agent capable of reducing the viscosity of rubber.

Another object of the present invention is to provide a rubber having a lower viscosity.
Another object of the present invention is to provide a method capable of efficiently producing a rubber having a lower viscosity.

  As a result of intensive studies to solve the above problems, the present inventor has found that a specific tetrazine-based compound can reduce the viscosity of rubber. As a result of further investigation based on such knowledge, the present inventors have completed the present invention.

［式中、Ｘ^１及びＸ^２は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。]
で表されるテトラジン化合物又はその塩を含む、低粘度化剤。
項２．
テトラジン化合物が、一般式（１）において、Ｘ^１及びＸ^２が、複素環基を示すテトラジン化合物である、項１に記載の低粘度化剤。
項３．
ゴムが、ジエン系ゴムを含む、項１又は２に記載の低粘度化剤。
項４．
ジエン系ゴムの含有割合が、ゴム１００質量部に対して７０質量部以上である、項３に記載の低粘度化剤。
項５．
ジエン系ゴムが、天然ゴム、イソプレンゴム、及び１，３−ブタジエンモノマーを含むモノマーを重合させたゴムからなる群から選択される少なくとも一種である、項３又は４に記載の低粘度化剤。
項６．
ゴムに項１〜５のいずれか一項に記載の低粘度化剤を配合した、低粘度化ゴム。
項７．
前記低粘度化剤を、ゴム１００質量部に対して０．１〜１０質量部配合した、項６に記載の低粘度化ゴム。
項８．
項１〜５のいずれか一項に記載の低粘度化剤、及びゴムを、８０〜２１０℃で混合する工程を含む、低粘度化ゴムの製造方法。
項９．
一般式（１）：

［式中、Ｘ^１及びＸ^２は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。]
で表されるテトラジン化合物又はその塩を含む、素練り促進剤。
項１０．
一般式（１）：

［式中、Ｘ^１及びＸ^２は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。]
で表されるテトラジン化合物又はその塩を含む、しゃく解剤。
項１１．
一般式（１）：

［式中、Ｘ^１及びＸ^２は、同一又は異なって、水素原子、アルキル基、アルキルチオ基、アラルキル基、アリール基、アリールチオ基、複素環基、又はアミノ基を示す。これら各基は、それぞれ１個以上の置換基を有していてもよい。]
で表されるテトラジン化合物又はその塩を含む、ペプタイザー。 That is, the present invention provides the following viscosity-lowering agent, low-viscosity rubber, and a method for producing the same.
Item 1.
A viscosity reducing agent for reducing the viscosity of rubber, the following general formula (1):

[Wherein, X ¹ and X ² are the same or different and each represents a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
The viscosity reducing agent containing the tetrazine compound or its salt represented by these.
Item 2.
Item 2. The viscosity reducing agent according to Item 1, wherein the tetrazine compound is a tetrazine compound in which X ¹ and X ² represent a heterocyclic group in the general formula (1).
Item 3.
Item 3. The viscosity reducing agent according to Item 1 or 2, wherein the rubber comprises a diene rubber.
Item 4.
Item 4. The viscosity reducing agent according to Item 3, wherein the content of the diene rubber is 70 parts by mass or more with respect to 100 parts by mass of the rubber.
Item 5.
Item 5. The viscosity reducing agent according to Item 3 or 4, wherein the diene rubber is at least one selected from the group consisting of natural rubber, isoprene rubber, and rubber obtained by polymerizing a monomer containing a 1,3-butadiene monomer.
Item 6.
A low viscosity rubber in which the low viscosity agent according to any one of Items 1 to 5 is blended with rubber.
Item 7.
Item 7. The reduced viscosity rubber according to Item 6, wherein 0.1 to 10 parts by mass of the viscosity reducing agent is blended with respect to 100 parts by mass of rubber.
Item 8.
Item 6. A method for producing a reduced viscosity rubber, comprising a step of mixing the viscosity reducing agent according to any one of Items 1 to 5 and a rubber at 80 to 210 ° C.
Item 9.
General formula (1):

[Wherein, X ¹ and X ² are the same or different and each represents a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
The peptizer which contains the tetrazine compound or its salt represented by these.
Item 10.
General formula (1):

[Wherein, X ¹ and X ² are the same or different and each represents a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
A peptizer containing a tetrazine compound represented by the formula:
Item 11.
General formula (1):

[Wherein, X ¹ and X ² are the same or different and each represents a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
The peptizer containing the tetrazine compound or its salt represented by these.

  The present invention can provide a viscosity reducing agent for reducing the viscosity of rubber. The viscosity reducing agent contains a tetrazine compound (1), and the viscosity of the rubber can be lowered by treating the diene rubber with the tetrazine compound (1).

  Since rubber treated with such a viscosity reducing agent has a lower viscosity than rubber not treated with a viscosity reducing agent, the processability is not only in the mixing process but also in subsequent processing processes such as the extrusion process. It can be expected to improve and thus improve productivity.

  The present invention is described in detail below.

［式中、Ｘ^１及びＸ^２は、前記に同じ。］ A viscosity reducing agent for reducing the viscosity of rubber A viscosity reducing agent for reducing the viscosity of the rubber of the present invention (hereinafter also referred to as "the viscosity reducing agent of the present invention" or simply "the viscosity reducing agent") Includes a compound represented by the following general formula (1) or a salt thereof (hereinafter sometimes referred to as “tetrazine compound (1)”), and preferably comprises a tetrazine compound (1).
General formula (1)

[Wherein, X ¹ and X ² are the same as above. ]

  The viscosity reducing agent of the present invention may contain a tetrazine compound other than the tetrazine compound (1) as long as the effects of the present invention are not impaired, but the content ratio of the tetrazine compound (1) is 50% by mass or more. Is preferable, 80 mass% or more is more preferable, and 90 mass% or more is particularly preferable.

  In the present specification, the “alkyl group” is not particularly limited and includes, for example, a linear, branched or cyclic alkyl group, and specifically includes, for example, a methyl group, an 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 Straight chain or branched alkyl group having 1 to 6 carbon atoms (particularly 1 to 4 carbon atoms), such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, etc. -8 (especially C3-C6) cyclic alkyl group etc. are mentioned. A preferable alkyl group is a linear or branched alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or n. -A pentyl group, particularly preferably a methyl group or an ethyl group.

  In the present specification, the “alkylthio group” is not particularly limited and includes, for example, a linear, branched or cyclic alkylthio group, and specifically includes, for example, a methylthio group, an ethylthio group, and an n-propylthio group. 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 A linear or branched alkylthio group having 1 to 6 carbon atoms (particularly 1 to 4 carbon atoms) such as a 3-methylpentylthio group; a cyclopropylthio group, a cyclobutylthio group, a cyclopentylthio group, a cyclohexylthio group Cyclic alkylthio groups having 3 to 8 carbon atoms (particularly 3 to 6 carbon atoms), such as a group, cycloheptylthio group, cyclooctylthio group, etc. And the like. The preferred alkylthio group is a methylthio group, an ethylthio group, an isopropylthio group, or an isobutylthio group, and more preferably a methylthio group or an ethylthio group.

  In the present specification, the “aralkyl group” is not particularly limited, and examples thereof include a benzyl group, a phenethyl group, a trityl group, a 1-naphthylmethyl group, a 2- (1-naphthyl) ethyl group, and 2- (2-naphthyl). ) And the like. A more preferred aralkyl group is a benzyl group or a phenethyl group, more preferably a benzyl group.

  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. A more preferred aryl group is a phenyl group or a naphthyl group, and more preferably a phenyl 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.

  In the present specification, the “heterocyclic group” is not particularly limited, and examples thereof include a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a 2-pyrazinyl group, a 2-pyrimidyl group, a 4-pyrimidyl group, 5-pyrimidyl group, 3-pyridyl group, 4-pyridazyl group, 4- (1,2,3-triazyl) group, 5- (1,2,3-triazyl) group, 2- (1,3,5- Triazyl) group, 3- (1,2,4-triazyl) group, 5- (1,2,4-triazyl) group, 6- (1,2,4-triazyl) group, 2-quinolyl group, 3- Quinolyl 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 Ryl group, 2-quinoxalyl group, 3-quinoxalyl group, 5-quinoxalyl group, 6-quinoxalyl group, 7-quinoxalyl group, 8-quinoxalyl group, 3-cinnolyl group, 4-cinnolyl group, 5-cinnolyl group, 6- Cinnolyl group, 7-cinnolyl group, 8-cinnolyl group, 2-quinazolyl group, 4-quinazolyl group, 5-quinazolyl group, 6-quinazolyl group, 7-quinazolyl group, 8-quinazolyl group, 1-phthalazyl group, 4- Phthalazyl group, 5-phthalazyl group, 6-phthalazyl group, 7-phthalazyl group, 8-phthalazyl group, 1-tetrahydroquinolyl group, 2-tetrahydroquinolyl group, 3-tetrahydroquinolyl group, 4-tetrahydroquinolyl group 5-tetrahydroquinolyl group, 6-tetrahydroquinolyl group, 7-tetrahydroquinolyl group, 8-tetrahydro Noryl group, 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, 2-furyl group, 3-furyl 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-isoxazolyl 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-thiadiazole) group, 2- (1,3,4-thiadiazol) group Group), 4- (1,2,3-oxadiazolyl) group, 5- (1,2,3-oxadiazolyl) group, 3- (1,2,4-oxadiazolyl) group, 5- (1,2, 4-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-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 2-isoindo group Group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 1-benzoimidazolyl group, 2-benzoimidazolyl group, 4-benzoimidazolyl group, 5-benzoimidazolyl group, 6- Benzoimidazolyl group, 7-benzimidazolyl group, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzo Furanyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 2-benzothienyl group, 3-benzothienyl group, 4-benzothienyl group , 5-benzothienyl group, 6-benzothienyl 7-benzothienyl group, 2-benzoxazolyl group, 4-benzoxazolyl group, 5-benzoxazolyl 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 Group, 2-morpholyl group, 3-morpholyl group, 4-morpholyl group, 1-piperazyl group, 2-piperazyl group, 1-piperidyl group, 2-piperidyl group, 3-piperidyl group, 4-piperidyl group, 2-tetrahydro Pyranyl group, 3-tetrahydropyranyl group, 4-tetrahydropyranyl group, 2-tetrahydrothiopyrani 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-tetrahydrothienyl group and the like. Among them, a preferable heterocyclic group is a pyridyl group, a furanyl group, a thienyl group, a pyrimidyl group or a pyrazyl group, and more preferably a pyridyl group.

In this specification, the “amino group” includes not only an amino group represented by —NH ₂ but also, for example, a methylamino group, an ethylamino group, an n-propylamino group, an isopropylamino group, 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 such as a dimethylamino group, an ethylmethylamino group or a diethylamino group (particularly A substituted amino group such as a dialkylamino group having two linear or branched alkyl groups having 1 to 4 carbon atoms is also included.

  Each of these alkyl group, alkylthio group, aralkyl group, aryl group, arylthio group, heterocyclic group and amino group may have one or more substituents. The “substituent” is not particularly limited, and examples thereof include halogen atoms, amino groups, aminoalkyl groups, alkoxycarbonyl groups, acyl groups, acyloxy groups, amide groups, carboxyl groups, carboxyalkyl groups, formyl groups, and nitrile groups. Nitro group, alkyl group, hydroxyalkyl group, hydroxyl group, alkoxy group, aryl group, aryloxy group, heterocyclic group, thiol group, alkylthio group, arylthio group and the like. 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, preferably a chlorine atom, a bromine atom and an iodine atom.

  In the present specification, the “aminoalkyl group” is not particularly limited, and examples thereof include aminoalkyl groups such as aminomethyl group, 2-aminoethyl group, and 3-aminopropyl group.

  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 includes, for example, carboxylic acid amide groups such as acetamido group and benzamide group; thioamide groups such as thioacetamide group and thiobenzamide group; N-methylacetamide group, N -N-substituted amide groups such as benzylacetamide group; and the like.

  In the present specification, the “carboxyalkyl group” is not particularly limited, and examples thereof include 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. A carboxy-alkyl group such as -n-hexyl group (preferably an alkyl group having 1 to 6 carbon atoms having a carboxy group).

  In the present specification, the “hydroxyalkyl group” is not particularly limited. For example, a hydroxyalkyl group such as a hydroxymethyl group, a hydroxyethyl group, a hydroxy-n-propyl group, a hydroxy-n-butyl group (preferably a hydroxyalkyl group) And an alkyl group having 1 to 6 carbon atoms having a group).

  In the present specification, the “alkoxy group” is not particularly limited and includes, for example, a linear, branched or cyclic alkoxy group, and specifically includes, for example, a methoxy group, an ethoxy group, and n-propoxy group. Linear group having 1 to 6 carbon atoms (particularly 1 to 4 carbon atoms) of the group, isopropoxy group, n-butoxy group, t-butoxy group, n-pentyloxy group, neopentyloxy group and n-hexyloxy group Or a branched alkoxy group having 3 to 8 carbon atoms (particularly 3 to 6 carbon atoms) such as cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, cycloheptyloxy group, cyclooctyloxy group, etc. A cyclic alkoxy group etc. are mentioned.

  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.

  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, trifluoroacetates and methanesulfonates; alkali metal salts such as sodium salts and potassium salts Alkaline earth metal salts such as magnesium salts and calcium salts; quaternary ammonium salts such as dimethylammonium and triethylammonium.

Among these tetrazine compounds (1), preferred compounds are those in which X ¹ and X ² are the same or different and may have a substituent, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, and a substituent. It is a compound which is an aryl group which may have a group, or a heterocyclic group which may have a substituent.

In a more preferred tetrazine compound (1), X ¹ and X ² are the same or different and have an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. It is a compound that is an optionally substituted heterocyclic group.

Further preferred tetrazine compound (1) is that X ¹ and X ² are the same or different and have a benzyl group which may have a substituent, a phenyl group which may have a substituent, or a substituent. 2-pyridyl group which may have, 3-pyridyl group which may have a substituent, 4-pyridyl group which may have a substituent, 2-furanyl group which may have a substituent , A thienyl group which may have a substituent, a 2-pyrazolyl group which may have a substituent, a 2-pyrimidyl group which may have a substituent, or a substituent. It is a compound that is a good 2-pyrazyl group, and among these, a 2-pyridyl group that may have a substituent, a 3-pyridyl group that may have a substituent, and a substituent. 4-pyridyl group which may be substituted or 2-furanyl which may have a substituent Compounds is particularly preferred.

Specifically, as the tetrazine compound (1), for example,
1,2,4,5-tetrazine,
3,6-bis (2-pyridyl) -1,2,4,5-tetrazine,
3,6-bis (3-pyridyl) -1,2,4,5-tetrazine,
3,6-bis (4-pyridyl) -1,2,4,5-tetrazine,
3,6-diphenyl-1,2,4,5-tetrazine,
3,6-dibenzyl-1,2,4,5-tetrazine,
3,6-bis (2-furanyl) -1,2,4,5-tetrazine,
3-methyl-6- (3-pyridyl) -1,2,4,5-tetrazine,
3,6-bis (3,5-dimethyl-1-pyrazolyl) -1,2,4,5-tetrazine,
3,6-bis (2-thienyl) -1,2,4,5-tetrazine,
3-methyl-6- (2-pyridyl) -1,2,4,5-tetrazine,
3,6-bis (4-hydroxyphenyl) -1,2,4,5-tetrazine,
3,6-bis (3-hydroxyphenyl) -1,2,4,5-tetrazine,
3,6-bis (2-pyrimidinyl) -1,2,4,5-tetrazine,
3,6-bis (2-pyrazyl) -1,2,4,5-tetrazine and the like can be mentioned.

  Among these, preferred tetrazine compounds (1) are 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-methyl-6- (3-pyridyl) -1,2,4,5-tetrazine and 3-methyl-6- (2-pyridyl) -1,2,4,5-tetrazine, and more preferred tetrazine compound (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.

  When the tetrazine compound (1) is a powder, the volume average diameter is not particularly limited. From the viewpoint of the effect of reducing the viscosity, 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 average diameter can be determined as a particle diameter corresponding to 50% of the integrated distribution curve from the volume standard particle size distribution using a particle size distribution measuring apparatus such as a laser light diffraction method.

  In addition, from the viewpoint of handling properties during handling and ignitability or explosive risk reduction, powders that have been surface-treated with oil, resin, stearic acid, etc. may be used, or the powder may be calcium carbonate, silica, You may mix and use fillers, such as carbon black.

  By adding the tetrazine compound (1) to the diene rubber, a rubber having a reduced viscosity can be obtained. This rubber has a lower viscosity than rubber not treated with the tetrazine compound (1). Therefore, the tetrazine compound (1) can reduce the viscosity of the rubber.

  Thus, by mix | blending the tetrazine compound (1) with a diene rubber, the viscosity of rubber | gum can be reduced and workability can be improved remarkably. That is, the viscosity reducing agent of the present invention can be used as a peptizer, a peptizer, or a peptizer.

  In this specification, the rubber is not particularly limited, and examples thereof include natural rubber (NR), synthetic diene rubber, and diene rubber such as a mixture of natural rubber and synthetic diene rubber.

  Natural rubber includes natural rubber such as natural rubber latex, technical grade rubber (TSR), smoked sheet (RSS), gutta-percha, Tochu-derived natural rubber, guayule-derived natural rubber, Russian dandelion-derived natural rubber, and plant component fermented rubber. In addition, modified natural rubbers such as epoxidized natural rubber, methacrylic acid-modified natural rubber, and styrene-modified natural rubber can be mentioned.

  Synthetic diene rubbers include styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene ternary copolymer 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 rubbers by a modification technique such as main chain modification, one-end modification, and both-end modification. Here, the modified functional group of the modified synthetic diene rubber includes at least one functional group containing a hetero atom such as an epoxy group, an amino group, an alkoxy group, a hydroxyl group, an alkoxysilyl group, a polyether group, or a carboxyl group. Things. Moreover, there is no restriction | limiting in particular about the ratio of cis / trans / vinyl of a diene part, It can use suitably in any ratio. The average molecular weight and molecular weight distribution of the diene rubber are not particularly limited, and an average molecular weight of 500 to 3,000,000 and a molecular weight distribution of 1.5 to 15 are preferable. Moreover, there is no restriction | limiting in particular also about the manufacturing method of synthetic diene rubber, What was synthesize | combined by emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, cationic polymerization etc. is mentioned.

  The rubber used in the present invention may contain a non-diene rubber such as butyl rubber as long as the effects of the present invention are not impaired. The content is usually less than 30 parts by weight, preferably 25 parts by weight or less, more preferably 20 parts by weight or less in 100 parts by weight of rubber.

  The glass transition point of the diene rubber is preferably in the range of -120 ° C to -15 ° C. Further, 50% by mass or more of the diene rubber is preferably a diene rubber having a glass transition point in the range of −70 ° C. to −20 ° C.

  One kind of rubber can be used alone, or two or more kinds of rubber can be mixed (blended). Among them, preferable rubber is natural rubber, IR, SBR, BR, or a mixture of two or more selected from these. Moreover, there is no restriction | limiting in particular in these blend ratios, It is preferable to mix | blend SBR, BR, or these mixtures in the ratio of 70-100 mass parts in 100 mass parts of rubber | gum, and mix | blend with 75-100 mass parts. It is more preferable. When blending a mixture of SBR and BR, the total amount of SBR and BR is preferably in the above range. Moreover, SBR at this time is 50-100 mass parts, and it is preferable that BR is the range of 0-50 mass parts.

Low-viscosity rubber The low-viscosity rubber of the present invention is a rubber in which the low-viscosity agent of the present invention is blended with the above-mentioned rubber. That is, the low viscosity rubber of the present invention is a rubber treated with the tetrazine compound (1).

  The low-viscosity rubber of the present invention may contain an untreated rubber and / or a low-viscosity agent as long as the effects of the present invention are not impaired.

  The low viscosity rubber of the present invention has a viscosity lower than that of the rubber not containing the above viscosity reducing agent since the above viscosity reducing agent is added. Therefore, the low viscosity rubber of the present invention is expected to improve processability not only in the mixing step but also in the subsequent processing steps due to the low viscosity.

Production method of low viscosity rubber The production method of the low viscosity rubber of the present invention is not particularly limited. The low viscosity rubber of the present invention is produced using, for example, rubber and the low viscosity agent of the present invention.

  The raw material for producing the low viscosity rubber of the present invention contains the above viscosity reducing agent and rubber. The rubber preferably contains 70 parts by mass or more of diene rubber in 100 parts by mass of rubber, more preferably 80 parts by mass or more, and 100 parts by mass of diene rubber. Further preferred. As a compounding quantity of this viscosity reducing agent, it is 0.1-10 mass parts normally with respect to 100 mass parts of rubber | gum, Preferably it is 0.25-5 mass parts, More preferably, it is 0.5-2 mass parts. What is necessary is just to adjust suitably so that.

  The method for producing a low-viscosity rubber of the present invention includes a step of mixing the above-mentioned low-viscosity agent and rubber. As a specific production method, when the rubber is solid, a method of mixing the rubber and a viscosity reducing agent (solid mixing method); when the rubber is liquid (liquid), a solution or emulsion of the rubber (Suspension) and a method of mixing a viscosity reducing agent (liquid mixing method).

  In the present specification, the term “mixing” includes the meaning of “kneading”.

  As the mixing temperature, for example, in the case of the above solid mixing method, it is preferably 80 to 210 ° C, more preferably 90 to 160 ° C, and further preferably 100 to 150 ° C. In the case of the liquid mixing method, the temperature is preferably 80 to 210 ° C, more preferably 90 to 160 ° C, and further preferably 100 to 150 ° C.

  The mixing time is not particularly limited. For example, in the case of a 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 more preferable. In the case of the liquid mixing method, the time is preferably 10 seconds to 60 minutes, more preferably 30 seconds to 40 minutes, and further preferably 60 seconds to 30 minutes. After the mixing reaction by the liquid mixing method, for example, the solvent in the reduced viscosity rubber can be removed (removed) under reduced pressure, and the solid reduced viscosity rubber can be recovered.

Use of low-viscosity rubber The use of the low-viscosity rubber of the present invention is not particularly limited, and examples thereof include tires, vibration-proof rubbers, conveyor belts, seismic isolation rubbers, and rubber parts thereof. Among these, a preferable use is a tire.

  When the low-viscosity rubber of the present invention is used in a tire, it is preferable to include a known compounding agent (inorganic filler, carbon black, etc.) that is usually compounded in the tire, in addition to the rubber and the viscosity reducing agent. When the above compounding agent is included, the rubber composition can be produced using the same production method as that for the conventional tire rubber composition except that the low viscosity rubber of the present invention is used as the rubber component.

  The low viscosity rubber of the present invention is mixed or kneaded using, for example, a Banbury mixer, a roll, an intensive mixer, a kneader, a twin screw extruder or the like. Then, it is extruded and processed in the extrusion process, and is formed as, for example, a tread member or a sidewall member. Subsequently, it is pasted and molded by a normal method on a tire molding machine to form a raw tire. The green tire is heated and pressed in a vulcanizer to obtain a tire.

  The low-viscosity rubber of the present invention can be suitably used for each member of a tire.

  Examples of tires include pneumatic tires (radial tires, bias tires, etc.), solid tires, and the like.

  There is no restriction | limiting in particular as a use of a tire, For example, the tire for passenger cars, the tire for heavy loads, the tire for motorcycles (motorcycle), a studless tire, etc. are mentioned, Especially, it can use suitably for a tire for passenger cars.

  There is no restriction | limiting in particular as a shape of a tire, a structure, a magnitude | size, and a material, According to the objective, it can select suitably.

  In a tire, the low-viscosity rubber of the present invention is particularly used 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.

  Especially, it is mentioned as one of the preferable aspects that the tire tread part or side wall part of a pneumatic tire is formed with the said rubber mixture.

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

  The sidewall portion is, for example, a portion from the lower side of the shoulder portion to the bead portion in the pneumatic radial tire, and is the portion that is most bent when traveling while protecting the carcass.

  The bead area portion is a portion having a function of fixing both ends of the carcass cord and simultaneously 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 a tread having a radial structure and the carcass. The carcass is tightened like a heel and the rigidity of the tread is increased.

  The carcass portion is a portion of the cord layer that forms the skeleton of the tire, and plays a role of withstanding the load, impact, and filling air pressure that the tire receives.

  The shoulder portion is the shoulder portion of the tire and serves to protect the carcass.

  The tire can be manufactured according to previously known methods in the field of tires. Moreover, as gas with which a tire is filled, normal or adjusted oxygen partial pressure air; 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, 24 g (0.23 mol) of 3-cyanopyridine was added with water. Hydrazine (15 g, 1.3 equivalents) and methanol (48 mL) were added, and the mixture was stirred at room temperature. Next, 3.6 g (15% by weight) of sulfur was added to this mixture, and a reflux tube was attached, followed by heating and stirring at an external temperature of 70 ° C. overnight. The reaction solution was ice-cooled, and 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 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 stirred overnight at room temperature. The precipitated crystals were filtered and the crystals were neutralized with 10% multilayer water to obtain crude crystals. The crude crystals were purified on a silica gel column (ethyl acetate) to obtain 8.4 g (red purple, needle-like crystals) of the title tetrazine compound (1b).
Melting point: 200 ° C.
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 1-10
Each component shown in Table 1 was mixed in the ratio (parts by mass) and mixed using a Banbury mixer. After the temperature of the mixture reached 140 ° C., the mixture was discharged to produce a low-viscosity rubber.

Viscosity test For rubber mixtures (test rubbers) prepared in Examples 1 to 10, an L-shaped rotor was used according to JIS K6300, and the Mooney viscosity ML (1 + 4) of the rubber composition was 100 ° C. I asked for it.

  In addition, the viscosity index was computed based on the following formula by making the rubber mixture of the same mixing | blending content as each Example into a reference except not mix | blending a tetrazine compound (1).

  The results are shown in Table 1.

  In addition, it shows that it is so low that the value of a viscosity index is small.

formula:
Viscosity index = {(viscosity of test rubber) / (reference viscosity)} × 100

Number average molecular weight measurement About rubber mixtures of Examples 1 to 3 and Example 5, Tosoh (EcoSEC) gel permeation chromatography (GPC), column used: TSKgel SuperHZM-M + TSKgel SuperHZM-M, tetrahydrofuran as solvent, standard Polystyrene was used as a sample, and measurement was performed at a measurement temperature of 40 ° C.

formula:
Number average molecular weight change rate (%) = {(number average molecular weight of test rubber) / (number average molecular weight of reference)} × 100

  The rubbers of any of the examples showed an excellent decrease in viscosity with respect to a comparative rubber not containing the tetrazine compound (1). Moreover, when the rate of change in the number average molecular weight of the reduced viscosity rubbers obtained in Examples 1, 2, 3 and 5 was confirmed, any of the reduced viscosity rubbers was used as a comparative rubber not containing the tetrazine compound (1). On the other hand, the results showed little change. From the above results, it was shown that the rubber was hardly decomposed or crosslinked during the kneading of the tetrazine compound (1) and the rubber, and a low viscosity rubber was obtained.

[Explanation of symbols in the table]
The raw materials used in Table 1 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: Product name “RC2557S” manufactured by PetroChina Dushanzi Petrochemical Company
* 5: Product name “PR2216”, manufactured by Zhenjiang Chimei Chemical Co., Ltd.
* 6: Product name “SBR1739” manufactured by Shenhua Chemical Industrial Co., Ltd.
* 7: Product name “BR9000”, manufactured by Sinopec Qilu Petrochemical Co., Ltd.
* 8: Product name “TSR20” manufactured by GUANGKEN RUBBER
* 9: Product name “RSS3”, manufactured by Chuka Kokusai Co., Ltd.
* 10: Product name “SKI-3” manufactured by Sterlitamak

Claims (7)

A viscosity reducing agent for reducing the viscosity of rubber, the following general formula (1):

[Wherein, X ¹ and X ² are the same or different and each represents a hydrogen atom, an alkyl group, an alkylthio group, an aralkyl group, an aryl group, an arylthio group, a heterocyclic group, or an amino group. Each of these groups may have one or more substituents. ]
The viscosity reducing agent containing the tetrazine compound or its salt represented by these. The viscosity reducing agent according to claim 1, wherein the tetrazine compound is a tetrazine compound in which X ¹ and X ² represent a heterocyclic group in the general formula (1). The low viscosity agent according to claim 1 or 2, wherein the rubber contains a diene rubber. The low viscosity agent of Claim 3 whose content rate of a diene rubber is 70 mass parts or more with respect to 100 mass parts of rubber | gum. A low-viscosity rubber in which the low-viscosity agent according to any one of claims 1 to 4 is blended with rubber. The low viscosity rubber according to claim 5, wherein 0.1 to 10 parts by mass of the viscosity reducing agent is blended with respect to 100 parts by mass of rubber. The manufacturing method of low viscosity rubber | gum including the process of mixing the viscosity reducing agent as described in any one of Claims 1-4, and rubber | gum at 80-210 degreeC.