JP5543392B2 - Copolymer, rubber composition and pneumatic tire - Google Patents

Description

The present invention relates to a copolymer, a rubber composition containing the copolymer, and a pneumatic tire containing the rubber composition.

In recent years, from the standpoint of saving resources and protecting the environment, it has been required to improve fuel efficiency by improving rolling resistance of tires, and also to improve wet grip performance to improve safety during driving.

Hysteresis loss is required to improve fuel economy, and wet skid resistance is required to improve wet grip performance. However, low hysteresis loss and high wet skid resistance are contradictory, and it is difficult to improve the fuel economy and wet grip performance in a balanced manner.

As a method for improving fuel economy and wet grip performance in a well-balanced manner, there is a method using silica as a filler. Silica has strong self-aggregation property and there is room for improvement in that it is difficult to disperse. In Patent Document 1, a styrene butadiene rubber terminal-modified with a specific compound containing a nitrogen atom and a silicon atom and an aliphatic carboxylic acid zinc salt are blended, and a rubber composition excellent in fuel efficiency and wet grip performance is obtained. Although a method for obtaining an object is described, provision of other methods is also sought.

JP 2010-111754 A

An object of the present invention is to solve the above problems and to provide a copolymer that can provide a rubber composition and a pneumatic tire with improved fuel economy and wet grip performance in a well-balanced manner.

（式中、Ｒ^１〜Ｒ^３は、炭化水素基を表す。ｒは整数を表す。） The present invention is obtained by copolymerizing 1,3-butadiene and a compound represented by the following general formula (I), and has a weight average molecular weight Mw of 1.0 × 10 ^{5 to} 2.5 × 10 ^6. It relates to a polymer.

^(Wherein, R 1 to R ³ are, .r representing the hydrocarbon radical is an integer.)

（式中、Ｒ^４及びＲ^５は、炭化水素基を表す。Ｒ^４及びＲ^５は互いに結合していてもよい。Ｒ^６は水素原子又は炭化水素基を表す。） The copolymer is preferably obtained by copolymerizing a compound represented by the following general formula (II) together with at least the 1,3-butadiene and the compound represented by the general formula (I). .

(In the formula, R ⁴ and R ⁵ represent a hydrocarbon group. R ⁴ and R ⁵ may be bonded to each other. R ⁶ represents a hydrogen atom or a hydrocarbon group.)

The copolymer is preferably modified with a modifier having a functional group containing at least one atom selected from the group consisting of nitrogen, oxygen and silicon.

The copolymer is preferably obtained by copolymerizing styrene together with at least the 1,3-butadiene and the compound represented by the general formula (I).

In the general formula (I), the hydrocarbon group represented by R ¹ , R ² and R ³ preferably has 1 to 10 carbon atoms.

In the general formula (I), r is preferably an integer of 1 to 30.

In the general formula (II), the hydrocarbon group represented by R ⁴ , R ⁵ and R ⁶ preferably has 1 to 10 carbon atoms.

The content of the compound represented by the general formula (I) is preferably 0.05 to 35% by mass.

The content of the compound represented by the general formula (II) is preferably 0.05 to 35% by mass.

（式中、Ｒ^７、Ｒ^８及びＲ^９は、同一若しくは異なって、アルキル基、アルコキシ基、シリルオキシ基、カルボキシル基、メルカプト基又はこれらの誘導体を表す。Ｒ^１０及びＲ^１１は、同一若しくは異なって、水素原子又はアルキル基を表す。ｎは整数を表す。）

（式中、Ｒ^１２、Ｒ^１３及びＲ^１４は、同一若しくは異なって、アルキル基、アルコキシ基、シリルオキシ基、カルボキシル基、メルカプト基又はこれらの誘導体を表す。Ｒ^１５は、環状エーテル基を表す。ｐ及びｑは整数を表す。） The modifying agent is preferably a compound represented by the following general formula (III) or the following general formula (IV).

(Wherein R ⁷ , R ⁸ and R ⁹ are the same or different and each represents an alkyl group, an alkoxy group, a silyloxy group, a carboxyl group, a mercapto group, or a derivative thereof. R ¹⁰ and R ¹¹ are the same or different. And represents a hydrogen atom or an alkyl group, and n represents an integer.)

(In formula, R <^12> , R <^13> and R < ¹⁴ > are the same or different, and represent an alkyl group, an alkoxy group, a silyloxy group, a carboxyl group, a mercapto group, or derivatives thereof. R < ¹⁵ > represents a cyclic ether group. p and q represent integers.)

The present invention also relates to a rubber composition containing the copolymer.

The rubber composition preferably contains 3% by mass or more of the copolymer in 100% by mass of the rubber component.

The rubber composition preferably contains 5 to 150 parts by mass of silica with respect to 100 parts by mass of the rubber component.

The present invention also relates to a pneumatic tire produced using the rubber composition.

According to the present invention, since it is a copolymer obtained by copolymerizing 1,3-butadiene and a specific compound and having a weight average molecular weight Mw within a specific range, a rubber composition using the copolymer In fuel and pneumatic tires, fuel economy and wet grip performance can be improved in a well-balanced manner.

（式中、Ｒ^１〜Ｒ^３は、炭化水素基を表す。ｒは整数を表す。） <Copolymer>
The copolymer of the present invention is obtained by copolymerizing at least 1,3-butadiene and a compound represented by the following general formula (I). Since the main chain of the copolymer is modified with a compound represented by the following general formula (I), interaction between the compound (particularly, an oxygen atom contained in the compound) and a filler occurs, The dispersibility of the filler is improved and the movement of the copolymer is restricted. As a result, hysteresis loss can be reduced, fuel efficiency can be improved, and good wet grip performance can be obtained, and these performances can be improved synergistically.

^(Wherein, R 1 to R ³ are, .r representing the hydrocarbon radical is an integer.)

The hydrocarbon group represented by R ¹ and R ² preferably has 1 to 10 carbon atoms. If the carbon number exceeds 10, the cost tends to be high. The number of carbon atoms is preferably 1-8, more preferably 1-6, and still more preferably 1-3, because the resulting copolymer is highly effective in improving fuel economy and wet grip performance.

Examples of the hydrocarbon group represented by R ¹ and R ² include a divalent aliphatic hydrocarbon group such as an alkylene group and a divalent aromatic hydrocarbon group such as an arylene group. R ¹ and R ² are preferably an alkylene group, more preferably a methylene group, an ethylene group, an n-propylene group, and an isopropylene group, because the resulting copolymer has high fuel economy and wet grip performance improvement effect. preferable. R ¹ and R ² may be the same or different.
When r is 2 or more, each R ² may be the same or different.

The hydrocarbon group represented by R ³ preferably has 1 to 10 carbon atoms. If the carbon number exceeds 10, the cost tends to be high. The number of carbon atoms is preferably 1-8, more preferably 1-6, from the viewpoint that the resulting copolymer is highly effective in improving fuel economy and wet grip performance.

Examples of the hydrocarbon group represented by R ³ include a monovalent aliphatic hydrocarbon group such as an alkyl group and a monovalent aromatic hydrocarbon group such as an aryl group. R ³ is preferably an alkyl group from the viewpoint of high fuel economy and wet grip performance improvement effect by the obtained copolymer, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, An isobutyl group, a sec-butyl group, and a tert-butyl group are more preferable.

As r (integer), 1-30 are preferable. Further, r is more preferably 1-20, further preferably 1-15, and particularly preferably 5-12. If r exceeds 30, the cost increases.

（上記一般式（Ｉ−Ｉ）中のＲ^１〜Ｒ^３及びｒは、上記一般式（Ｉ）中のＲ^１〜Ｒ^３及びｒと同様である。） Further, among the compounds represented by the general formula (I), the compound represented by the following general formula (I-I) is highly effective in improving fuel economy and wet grip performance due to the obtained copolymer. Compounds are preferred.

^(R 1 to R ³ and r in the general formula (I-I) is the same as ^R 1 to R ³ and r in the general formula (I).)

The compound represented by the general formula (I) can be synthesized by a known method. For example, it can be obtained by reacting a halogenated alkylstyrene with a polyalkylene glycol monoalkyl ether in the presence of a strong base. Specifically, using N, N-dimethylformamide as a solvent, a halogenated alkylstyrene (for example, 4-chloromethylstyrene) and a polyalkylene glycol monoalkyl ether (triethylene glycol monoalkyl ether) in the presence of sodium hydride. And butyl ether). The compound represented by general formula (I) may be used independently and may combine 2 or more types.

The content of the compound represented by the general formula (I) in the copolymer is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and preferably 35% by mass or less. More preferably, it is 20 mass% or less, More preferably, it is 15 mass% or less, Especially preferably, it is 5 mass% or less, Most preferably, it is 2 mass% or less. If it is less than 0.05% by mass, it is difficult to obtain an effect of improving fuel economy and wet grip performance, while if it exceeds 35% by mass, the cost tends to be high.

（式中、Ｒ^４及びＲ^５は、炭化水素基を表す。Ｒ^４及びＲ^５は互いに結合していてもよい。Ｒ^６は水素原子又は炭化水素基を表す。） The copolymer is preferably obtained by copolymerizing a compound represented by the following general formula (II) together with at least the 1,3-butadiene and the compound represented by the general formula (I). Thereby, since the main chain is modified with the compound represented by the following general formula (II) together with the compound represented by the above general formula (I), these compounds (especially oxygen atoms contained in the compound) Interaction between the filler and the filler, the dispersibility of the filler is further improved, and the movement of the copolymer is further restricted. As a result, hysteresis loss is further reduced and fuel efficiency can be further improved, and better wet grip performance can be obtained, and these performances can be improved more synergistically.

(In the formula, R ⁴ and R ⁵ represent a hydrocarbon group. R ⁴ and R ⁵ may be bonded to each other. R ⁶ represents a hydrogen atom or a hydrocarbon group.)

The hydrocarbon group represented by R ⁴ and R ⁵ preferably has 1 to 10 carbon atoms. If the carbon number exceeds 10, the cost tends to be high. The number of carbon atoms is preferably 1-8, more preferably 1-6, from the viewpoint that the resulting copolymer is highly effective in improving fuel economy and wet grip performance.

Examples of the hydrocarbon group represented by R ⁴ and R ⁵ include the same groups as those for R ³ . Examples of the hydrocarbon group in which R ⁴ and R ⁵ are bonded to each other include alkylene groups such as an ethylene group formed by connecting R ⁴ and R ⁵ . In addition, the carbon number of the hydrocarbon group formed by connecting R ⁴ and R ⁵ is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, and particularly preferably 1 to 4. . R ⁴ and R ⁵ are preferably an alkyl group or an alkylene group, and n-butyl group, methyl group, ethyl group, n- A propyl group, an isopropyl group, and an ethylene group are more preferable. R ⁴ and R ⁵ may be the same or different. R ⁴ and R ⁵ are preferably bonded to each other.

The hydrocarbon group represented by R ⁶ preferably has 1 to 10 carbon atoms. If the carbon number exceeds 10, the cost tends to be high. The number of carbon atoms is preferably 1 to 6, more preferably 1 to 4, from the viewpoint that the resulting copolymer is highly effective in improving fuel economy and wet grip performance.

Examples of the hydrocarbon group represented by R ⁶ include the same groups as those for R ³ . R ⁶ is preferably a hydrogen atom from the viewpoint that the resulting copolymer is highly effective in improving fuel economy and wet grip performance.

（上記一般式（ＩＩ−Ｉ）中のＲ^４〜Ｒ^６は、上記一般式（ＩＩ）中のＲ^４〜Ｒ^６と同様である。） Further, among the compounds represented by the general formula (II), the compound represented by the following general formula (II-I) is highly effective in improving fuel economy and wet grip performance by the obtained copolymer. Compounds are preferred.

^(R 4 to R ⁶ in the general formula (II-I) is the same as ^R 4 to R ⁶ in the general formula (II).)

The compound represented by the general formula (II) can be obtained by acetalizing vinylbenzaldehyde (for example, 4-vinylbenzaldehyde) by a known method. Specific examples thereof include 4-vinylbenzaldehyde dibutyl acetal, 4-vinylbenzaldehyde ethylene acetal, 4-vinylbenzaldehyde dimethyl acetal, 4-vinylbenzaldehyde diethyl acetal, 4-vinylbenzaldehyde di-n-propyl acetal, 4-vinylbenzaldehyde diisopropyl. Examples include acetal and 3-vinylbenzaldehyde dibutyl acetal. These may be used alone or in combination of two or more.

The content of the compound represented by the general formula (II) in the copolymer is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and preferably 35% by mass or less. More preferably, it is 20 mass% or less, More preferably, it is 15 mass% or less, Especially preferably, it is 5 mass% or less, Most preferably, it is 2 mass% or less. If it is less than 0.05% by mass, it is difficult to obtain an effect of improving fuel economy and wet grip performance, while if it exceeds 35% by mass, the cost tends to be high.

The copolymer may be obtained by copolymerizing styrene with at least the 1,3-butadiene and the compound represented by the general formula (I). The copolymer is obtained by copolymerizing styrene with at least the 1,3-butadiene, the compound represented by the general formula (I) and the compound represented by the general formula (II). There may be. When the copolymer contains styrene, the styrene content is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less. More preferably, it is 25 mass% or less. If it is less than 5% by mass, the wet grip performance tends to deteriorate, whereas if it exceeds 40% by mass, the fuel efficiency tends to deteriorate.

The content of 1,3-butadiene in the copolymer is not particularly limited, and may be appropriately adjusted according to the content of other components, but is preferably 40% by mass or more, more preferably 60% by mass or more. In addition, it is preferably 90% by mass or less, more preferably 85% by mass or less, and still more preferably 80% by mass or less. If it is in the said range, the effect of this invention will be acquired favorably.

The content of the compound represented by the general formula (I), the compound represented by the general formula (II), 1,3-butadiene and styrene in the copolymer can be measured by the method of Examples described later.

<Modifier>
In the copolymer of the present invention, at least one terminal is preferably modified with a terminal modifier (modifier that modifies the terminal). The terminal modifier is preferably a modifier having a functional group containing at least one atom selected from the group consisting of nitrogen, oxygen and silicon.

Accordingly, the main chain of the copolymer is modified with the compound represented by the general formula (I) or the compound represented by the general formula (II) together with the compound represented by the general formula (I). In addition, since at least one terminal is modified with the modifying agent, interaction between the compound and the filler and interaction between the modifying agent and the filler occur, and the dispersibility of the filler is further improved. In addition, the movement of the copolymer is more restricted. Note that the action of constraining this copolymer is higher in terminal modification than in main chain modification. As a result, hysteresis loss is further reduced and fuel efficiency can be further improved, and better wet grip performance can be obtained, and these performances can be improved more synergistically.

Examples of the functional group include amino group, amide group, alkoxysilyl group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, carboxyl group, hydroxyl group, nitrile group, and pyridyl group. . Of these, an amino group (preferably an alkylamino group, more preferably a dialkylamino group), an alkoxysilyl group, and an ether group are preferable from the viewpoint that the effect of improving fuel economy and wet grip performance is great.

Examples of the modifier include 3-glycidoxypropyltrimethoxysilane, (3-triethoxysilylpropyl) tetrasulfide, 1- (4-N, Ndimethylaminophenyl) -1-phenylethylene, 1,1- Dimethoxytrimethylamine, 1,2-bis (trichlorosilyl) ethane, 1,3,5-tris (3-triethoxysilylpropyl) isocyanurate, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate, 1,3-dimethyl-2-imidazolidinone, 1,3-propanediamine, 1,4-diaminobutane, 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole, 1-glycidyl- 4- (2-pyridyl) piperazine, 1-glycidyl-4-phenylpiperazine, 1-glycidyl -4-methylpiverazine, 1-glycidyl-4-methylhomopiverazine, 1-glycidylhexamethyleneimine, 11-aminoundecyltriethoxysilane, 11-aminoundecyltrimethoxysilane, 1-benzyl-4-glycidylpiperazine 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (4-morpholinodithio) benzothiazole, 2- (6-aminoethyl) -3-aminopropyltrimethoxysilane, 2- (triethoxy Silylethyl) pyridine, 2- (trimethoxysilylethyl) pyridine, 2- (2-pyridylethyl) thiopropyltrimethoxysilane, 2- (4-pyridylethyl) thioprovir trimethoxysilane, 2,2-diethoxy- 1,6-diaza-2-silacyclooctane, 2 2-dimethoxy-1,6-diaza-2-silacyclooctane, 2,3-dichloro-1,4-naphthoquinone, 2,4-dinitrobenzenesulfonyl chloride, 2,4-tolylene diisocyanate, 2- (4 -Pyridylethyl) triethoxysilane, 2- (4-pyridylethyl) trimethoxysilane, 2-cyanoethyltriethoxysilane, 2-tributylstannyl-1,3-butadiene, 2- (trimethoxysilylethyl) pyridine, 2 -Vinylpyridine, 2- (4-pyridylethyl) triethoxysilane, 2- (4-pyridylethyl) trimethoxysilane, 2-laurylthioethylphenylketone, 3- (1-hexamethyleneimino) propyl (triethoxy) silane , 3- (1,3-Dimethylbutylidene) aminopropyltriethoxysilane Lan, 3- (1,3-dimethylbutylidene) aminopropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane, 3- (m-aminophenoxy) propyltrimethoxysilane, 3- (N , N-dimethylamino) propyltriethoxysilane, 3- (N, N-dimethylamino) propyltrimethoxysilane, 3- (N-methylamino) propyltriethoxysilane, 3- (N-methylamino) propyltrimethoxy Silane, 3- (N-allylamino) propyltrimethoxysilane, 3,4-diaminobenzoic acid, 3-aminopropyldimethylethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyl Tris (methoxydiethoxy) silane, 3-amino Propyldiisopropylethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-diethylaminopropyltrimethoxysilane 3-diethoxy (methyl) silylpropyl succinic anhydride, 3- (N, N-diethylaminopropyl) triethoxysilane, 3- (N, N-diethylaminopropyl) trimethoxysilane, 3- (N, N-dimethylamino) Propyl) diethoxymethylsilane, 3- (N, N-dimethylaminopropyl) triethoxysilane, 3- (N, N-dimethylaminopropyl) trimethoxysilane, 3-triethoxysilylpropyl succinic anhydride, 3-tri Toxisilylpropyl acetic anhydride, 3-triphenoxysilylpropyl succinic anhydride, 3-triphenoxysilylpropyl acetic anhydride, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-hexamethyleneiminopropyltriethoxysilane, 3-mercaptopropyl Trimethoxysilane, (3-triethoxysilylpropyl) diethylenetriamine, (3-trimethoxysilylpropyl) diethylenetriamine, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4′- (Imidazol-1-yl) -acetophenone, 4- [3- (N, N-diglycidylamino) propyl] morpholine, 4-glycidyl-2,2,6,6-tetramethylpiberidinyloxy, 4- amino Butyltriethoxysilane, 4-vinylpyridine, 4-morpholinoacetophenone, 4-morpholinobenzophenone, m-aminophenyltrimethoxysilane, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1- Propanamine, N- (1,3-dimethylbutylidene) -3- (trimethoxysilyl) -1-propanamine, N- (1-methylethylidene) -3- (triethoxysilyl) -1-propanamine, N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltri Ethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-a Noethyl) -11-aminoundecyltriethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, N- (2-aminoethyl) -3-aminoisobutylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminoisobutylmethyldimethoxysilane, N- (3-diethoxymethylsilylpropyl) succinimide, N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole, N- (3 -Triethoxysilylpropyl) pyrrole, N- (3-trimethoxysilylpropyl) pyrrole, N-3- [amino (polypropyleneoxy)] aminopropyltrimethoxysilane, N- [5- (triethoxysilyl) -2- Aza-1-oxopentyl] caprolactam, N- [5- (trimethoxy) Silyl) -2-aza-1-oxopentyl] caprolactam, N- (6-aminohexyl) aminomethyltriethoxysilane, N- (6-aminohexyl) aminomethyltrimethoxysilane, N-allyl-aza-2, 2-diethoxysilacyclopentane, N-allyl-aza-2,2-dimethoxysilacyclopentane, N- (cyclohexylthio) phthalimide, Nn-butyl-aza-2,2-diethoxysilacyclopentane, N -N-butyl-aza-2,2-dimethoxysilacyclopentane, N, N, N ', N'-tetraethylaminobenzophenone, N, N, N', N'-tetramethylthiourea, N, N, N ' , N′-tetramethylurea, N, N′-ethyleneurea, N, N′-diethylaminobenzophenone, N, N′-diethylaminobenzopheno N, N′-diethylaminobenzofuran, methyl N, N′-diethylcarbamate, N, N′-diethylurea, (N, N-diethyl-3-aminopropyl) triethoxysilane, (N, N-diethyl) -3-aminopropyl) trimethoxysilane, N, N-dioctyl-N′-triethoxysilylpropylurea, N, N-dioctyl-N′-trimethoxysilylpropylurea, methyl N, N-diethylcarbamate, N , N-diglycidylcyclohexylamine, N, N-dimethyl-o-toluidine, N, N-dimethylaminostyrene, N, N-diethylaminopropylacrylamide, N, N-dimethylaminopropylacrylamide, N-ethylaminoisobutyltriethoxy Silane, N-ethylaminoisobutyltrimethoxysilane, -Ethylaminoisobutylmethyldiethoxysilane, N-oxydiethylene-2-benzothiazolesulfenamide, N-cyclohexylaminopropyltriethoxysilane, N-cyclohexylaminopropyltrimethoxysilane, N-methylaminopropylmethyldimethoxysilane, N -Methylaminopropylmethyldiethoxysilane, N-vinylbenzylazacycloheptane, N-phenylpyrrolidone, N-phenylaminopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, N-phenylaminomethyltriethoxysilane, N -Phenylaminomethyltrimethoxysilane, n-butylaminopropyltriethoxysilane, n-butylaminopropyltrimethoxysilane, N-methylaminopropyltri Ethoxysilane, N-methylaminopropyltrimethoxysilane, N-methyl-2-piperidone, N-methyl-2-pyrrolidone, N-methyl-ε-caprolactam, N-methylindolinone, N-methylpyrrolidone, p- ( 2-dimethylaminoethyl) styrene, p-aminophenyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, (aminoethylamino) -3-isobutyldiethoxysilane, (amino Ethylamino) -3-isobutyldimethoxysilane, (aminoethylaminomethyl) phenethyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, acrylic acid, diethyl adipate, acetamidopropyltrimethoxysilane, amino Enyltrimethoxysilane, aminobenzophenone, ureidopropyltriethoxysilane, ureidopropyltrimethoxysilane, ethylene oxide, octadecyldimethyl (3-trimethoxysilylpropyl) ammonium chloride, glycidoxypropyltriethoxysilane, glycidoxypropyltrimethoxysilane , Glycerol tristearate, chlorotriethoxysilane, chloropropyltriethoxysilane, chloropolydimethylsiloxane, chloromethyldiphenoxysilane, diallyldiphenyltin, diethylaminomethyltriethoxysilane, diethylaminomethyltrimethoxysilane, diethyl (glycidyl) amine, diethyl Dithiocarbamic acid 2-benzothiazoyl ester, diethoxydichlorosilane, ( (Cyclohexylaminomethyl) triethoxysilane, (cyclohexylaminomethyl) trimethoxysilane, diglycidylpolysiloxane, dichlorodiphenoxysilane, dicyclohexylcarbodiimide, divinylbenzene, diphenylcarbodiimide, diphenylcyanamide, diphenylmethane diisocyanate, diphenoxymethylchlorosilane, dibutyldichloro Tin, dimethyl (acetoxy-methylsiloxane) polydimethylsiloxane, dimethylaminomethyltriethoxysilane, dimethylaminomethyltrimethoxysilane, dimethyl (methoxy-methylsiloxane) polydimethylsiloxane, dimethylimidazolidinone, dimethylethyleneurea, dimethyldichlorosilane , Dimethylsulfoyl chloride, silsesquioxane Sorbitan trioleate, sorbitan monolaurate, titanium tetrakis (2-ethylhexoxide), tetraethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraphenoxysilane, tetramethylthiuram disulfide, tetramethoxy Silane, triethoxyvinylsilane, tris (3-trimethoxysilylpropyl) cyanurate, triphenyl phosphate, triphenoxychlorosilane, triphenoxymethylsilicon, triphenoxymethylsilane, carbon dioxide, bis (triethoxysilylpropyl) amine, bis (tri Methoxysilylpropyl) amine, bis [3- (triethoxysilyl) propyl] ethylenediamine, bis [3- (trimethoxysilyl) propyl] Range amine, bis [3- (triethoxysilyl) propyl] urea, bis [(trimethoxysilyl) propyl] urea, bis (2-hydroxymethyl) -3-aminopropyltriethoxysilane, bis (2-hydroxymethyl) -3-aminopropyltrimethoxysilane, bis (2-ethylhexanoate) tin, bis (2-methylbutoxy) methylchlorosilane, bis (3-triethoxysilylpropyl) tetrasulfide, bisdiethylaminobenzophenone, bisphenol A diglycidyl Ether, bisphenoxyethanol fluorenediglycidyl ether, bis (methyldiethoxysilylpropyl) amine, bis (methyldimethoxysilylpropyl) -N-methylamine, hydroxymethyltriethoxysilane, vinyltri (2-ethylhexyloxy) silane, vinylbenzyldiethylamine, vinylbenzyldimethylamine, vinylbenzyltributyltin, vinylbenzylpiperidine, vinylbenzylpyrrolidine, pyrrolidine, phenyl isocyanate, phenylisothiocyanate, (phenylaminomethyl) methyldimethoxysilane, ( Phenylaminomethyl) methyldiethoxysilane, phthalic acid amide, hexamethylene diisocyanate, benzylidene aniline, polydiphenylmethane diisocyanate, polydimethylsiloxane, methyl-4-pyridyl ketone, methylcaprolactam, methyltriethoxysilane, methyltriphenoxysilane, Examples include methyl lauryl thiopropionate and silicon tetrachloride.

（式中、Ｒ^７、Ｒ^８及びＲ^９は、同一若しくは異なって、アルキル基、アルコキシ基、シリルオキシ基、カルボキシル基（−ＣＯＯＨ）、メルカプト基（−ＳＨ）又はこれらの誘導体を表す。Ｒ^１０及びＲ^１１は、同一若しくは異なって、水素原子又はアルキル基を表す。ｎは整数を表す。）

（式中、Ｒ^１２、Ｒ^１３及びＲ^１４は、同一若しくは異なって、アルキル基、アルコキシ基、シリルオキシ基、カルボキシル基（−ＣＯＯＨ）、メルカプト基（−ＳＨ）又はこれらの誘導体を表す。Ｒ^１５は、環状エーテル基を表す。ｐ及びｑは整数を表す。） From the viewpoint that the effect of improving fuel economy and wet grip performance is great, the modifier is preferably a compound represented by the following general formula (III) or the following general formula (IV), The compounds represented are more preferred.

(Wherein R ⁷ , R ⁸ and R ⁹ are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, a carboxyl group (—COOH), a mercapto group (—SH) or a derivative thereof. R ¹⁰ And R ¹¹ are the same or different and each represents a hydrogen atom or an alkyl group, and n represents an integer.)

(In formula, R <^12> , R <^13> and R < ¹⁴ > are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, a carboxyl group (-COOH), a mercapto group (-SH), or these derivatives. R < ¹⁵ >. Represents a cyclic ether group, and p and q represent an integer.)

In the compound represented by the general formula (III), examples of the alkyl group for R ⁷ , R ⁸ and R ⁹ include an alkyl group having 1 to 4 carbon atoms such as a methyl group (preferably having 1 to 3 carbon atoms). Etc. Examples of the alkoxy group of R ⁷ , R ⁸ and R ⁹ include an alkoxy group having 1 to 8 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms) such as a methoxy group. . The alkoxy group includes a cycloalkoxy group and an aryloxy group. Examples of the silyloxy group for R ⁷ , R ^8, and R ⁹ include a silyloxy group substituted with an aliphatic group having 1 to 20 carbon atoms or an aromatic group (such as a trimethylsilyloxy group or a tribenzylsilyloxy group). .

In the compound represented by the general formula (III), examples of the alkyl group of R ¹⁰ and R ¹¹ include the same groups as the alkyl groups (alkyl groups of R ⁷ , R ⁸ and R ⁹ ). it can.

R ⁷ , R ⁸ and R ⁹ are preferably an alkoxy group, and R ¹⁰ and R ¹¹ are preferably an alkyl group because the fuel efficiency and the effect of improving wet grip performance are great.

n (integer) is preferably 0 to 5 for the reason of availability. Furthermore, n is more preferably 2 to 4, and most preferably 3. If n is 6 or more, the cost increases.

Specific examples of the compound represented by the general formula (III) include 3- (N, N-dimethylamino) propyltriethoxysilane and 3- (N, N-dimethylamino) propyltrimethyl exemplified as the modifier. And methoxysilane. Of these, 3- (N, N-dimethylamino) propyltrimethoxysilane is preferable.

In the compound represented by the general formula (IV), R ¹² , R ¹³ and R ¹⁴ are the same as R ⁷ , R ⁸ and R ⁹ in the compound represented by the general formula (III). As R ¹² , R ^13, and R ¹⁴ , an alkoxy group is preferable because the effect of improving fuel economy and wet grip performance is great.

In the compound represented by the general formula (IV), examples of the cyclic ether group represented by R ¹⁵ include a cyclic ether group having one ether bond such as an oxirane group and a cyclic ether group having two ether bonds such as a dioxolane group. And cyclic ether groups having three ether bonds such as a trioxane group. Among these, a cyclic ether group having one ether bond is preferable, and an oxirane group is more preferable because the effect of improving fuel economy and wet grip performance is great. Carbon number of a cyclic ether group becomes like this. Preferably it is 2-7, More preferably, it is 2-4. The cyclic ether group preferably has no unsaturated bond in the ring skeleton.

The p (integer) is preferably 0 to 5 for reasons of availability and reactivity. Further, p is more preferably from 2 to 4, and most preferably 3. If p is 6 or more, the cost increases.

q (integer) is preferably 0 to 5 for reasons of availability and reactivity. Furthermore, q is more preferably 1 to 3, and most preferably 1. If q is 6 or more, the cost increases.

Specific examples of the compound represented by the general formula (IV) include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane exemplified as the modifier. Of these, 3-glycidoxypropyltrimethoxysilane is preferable.

Examples of suitable modifiers other than the compound represented by the general formula (III) or (IV) include N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole, silicon tetrachloride and the like. .

<Method for producing copolymer>
The copolymer of the present invention in which the main chain is modified includes, for example, a compound represented by 1,3-butadiene and general formula (I), and, if necessary, a compound represented by general formula (II), It can be produced by copolymerizing with styrene, and specifically can be produced by the following production method. In addition, the copolymer of the present invention in which the main chain and the terminal are modified is, for example, further reacted with the above modifier on at least one terminal of the obtained main chain-modified copolymer. Specifically, it can be manufactured by the following manufacturing method.

(Polymerization method)
The polymerization method of the copolymer is not particularly limited, and any of solution polymerization method, gas phase polymerization method, and bulk polymerization method can be used, but the stability of the compound represented by the general formula (I) is particularly high. From the viewpoint, a solution polymerization method is preferable. Moreover, any of a batch type and a continuous type may be sufficient as the superposition | polymerization form.

When the solution polymerization method is used, the monomer concentration in the solution (the total of styrene, 1,3-butadiene, the compound represented by the general formula (I), the compound represented by the general formula (II), etc.) is , Preferably 5% by mass or more, more preferably 10% by mass or more. When the monomer concentration in the solution is less than 5% by mass, the amount of the copolymer obtained is small and the cost tends to be high. The monomer concentration in the solution is preferably 50% by mass or less, more preferably 30% by mass or less. If the monomer concentration in the solution exceeds 50% by mass, the solution viscosity becomes too high, stirring becomes difficult, and polymerization tends to be difficult.

(Polymerization initiator in anionic polymerization)
When anionic polymerization is performed, the polymerization initiator is not particularly limited, but an organic lithium compound is preferably used. As the organic lithium compound, those having an alkyl group having 2 to 20 carbon atoms are preferable. For example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, tert- Octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, cyclopentyl lithium, reaction products of diisopropenylbenzene and butyl lithium, etc. Among these, n-butyllithium or sec-butyllithium is preferable from the viewpoints of availability and safety.

(Method of anionic polymerization)
There is no restriction | limiting in particular as a method of manufacturing a copolymer by anionic polymerization using the said organolithium compound as a polymerization initiator, A conventionally well-known method can be used. Specifically, in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, butyl lithium or the like is used as a polymerization initiator, and a randomizer is used as necessary. In the presence of 1,3-butadiene and the compound represented by the general formula (I), and if necessary, the compound represented by the general formula (II), styrene and the like may be anionically polymerized. In addition, after anionic polymerization, you may add a well-known anti-aging agent and alcohol etc. for the purpose of stopping a polymerization reaction as needed.

(Hydrocarbon solvents in anionic polymerization)
The hydrocarbon solvent is preferably one having 3 to 8 carbon atoms, such as propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene and trans-2. -Butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like.

(Randomizer in anionic polymerization)
The randomizer is a microstructure control of a conjugated diene moiety in a copolymer (for example, an increase in 1,2-bonds in butadiene, etc.) and a control of the composition distribution of monomer units in the copolymer (for example, It is a compound having an action such as a butadiene unit, randomization of a styrene unit, etc. in a butadiene-styrene copolymer. The randomizer is not particularly limited, and any known compound generally used as a conventional randomizer can be used. For example, dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, bistetrahydrofurylpropane, triethylamine, pyridine, N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, 1,2-di Examples include ethers such as piperidinoethane and tertiary amines. Further, potassium salts such as potassium-t-amylate and potassium-t-butoxide, and sodium salts such as sodium-t-amylate can also be used.

The amount of randomizer used is preferably 0.01 molar equivalents or more, more preferably 0.05 molar equivalents or more per mole of the polymerization initiator. If the amount of randomizer used is less than 0.01 molar equivalent, the effect of addition tends to be small and it tends to be difficult to randomize. The amount of randomizer used is preferably 1000 molar equivalents or less, more preferably 500 molar equivalents or less per mole of the polymerization initiator. When the amount of the randomizer used exceeds 1000 molar equivalents, the monomer reaction rate changes greatly, and conversely, it tends to be difficult to randomize.

It does not specifically limit as the modification method by a modifier, A well-known method can be used. For example, after synthesizing a copolymer whose main chain is modified by anionic polymerization, the anion at the end of the copolymer reacts with the functional group of the modifying agent by bringing the copolymer into contact with the modifying agent. The terminal end of the copolymer is modified. As a result, a copolymer having a modified main chain and terminal is obtained. The amount of the modifier to be reacted is usually 0.01 to 10 parts by mass with respect to 100 parts by mass of the copolymer. In the copolymer of the present invention, at least one terminal is preferably modified, and both terminals are more preferably modified.

In the present invention, after carrying out the modification reaction with the above-mentioned modifier, a known anti-aging agent or alcohol may be added as necessary to stop the polymerization reaction.

The weight average molecular weight Mw of the copolymer is 1.0 × 10 ^{5 to} 2.5 × 10 ⁶ . When Mw is less than 1.0 × 10 ^5, fuel economy tends to be poor, whereas when Mw exceeds 2.5 × 10 ⁶ , workability tends to be deteriorated. The lower limit of Mw is preferably 2.0 × 10 ⁵ or more, more preferably 3.0 × 10 ⁵ or more, and the upper limit is preferably 1.5 × 10 ⁶ or less, more preferably 1.0 × 10 ^6. It is as follows.
In addition, Mw can be adjusted suitably by methods, such as changing the quantity of the polymerization initiator used at the time of superposition | polymerization, and can be measured by the method of the below-mentioned Example.

<Rubber composition>
(Rubber component)
The above copolymer can be used as a rubber component of a rubber composition. The content of the copolymer in 100% by mass of the rubber component is preferably 3% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more. If the amount is less than 3% by mass, the effect of improving fuel economy and wet grip performance tends to be difficult to obtain. Further, the content of the copolymer is preferably 50% by mass or less, more preferably 35% by mass or less, and still more preferably 25% by mass or less. When it exceeds 50 mass%, it tends to be expensive.

The above copolymer may be used in combination with other rubber components. As another rubber component, it is preferable to use a diene rubber. As the diene rubber, natural rubber and diene synthetic rubber can be used. Examples of the diene rubber include isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), and acrylonitrile butadiene rubber (NBR). Chloroprene rubber (CR), butyl rubber (IIR) and the like. Among these, NR, BR, and SBR are preferable because of low fuel consumption and wet grip performance, and it is more preferable to use NR, BR, and SBR together with the copolymer. These rubber components may be used alone or in combination of two or more.

The content of NR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 15% by mass or more, and preferably 35% by mass or less, more preferably 25% by mass or less. Within the above range, low fuel consumption and wet grip performance can be obtained in a well-balanced manner.

The content of BR in 100% by mass of the rubber component is preferably 1% by mass or more, more preferably 5% by mass or more, and preferably 25% by mass or less, more preferably 15% by mass or less. Within the above range, low fuel consumption and wet grip performance can be obtained in a well-balanced manner.

The content of SBR in 100% by mass of the rubber component is preferably 35% by mass or more, more preferably 45% by mass or more, and preferably 85% by mass or less, more preferably 75% by mass or less, still more preferably. 65% by mass or less, particularly preferably 55% by mass or less. Within the above range, low fuel consumption and wet grip performance can be obtained in a well-balanced manner.

(silica)
The rubber composition of the present invention preferably contains silica as a reinforcing agent. Dispersion of silica is promoted by the copolymer, and the effect of improving fuel economy and wet grip performance can be enhanced. Silica that can be used is not particularly limited, and those commonly used in the tire industry can be used. Silica may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 50 m ² / g or more, more preferably 80 m ² / g or more, and preferably 300 m ² / g or less, more preferably 250 m ² / g. It is as follows. Silica having a nitrogen adsorption specific surface area of less than 50 m ² / g has a small reinforcing effect and tends to decrease the wear resistance, and silica exceeding 300 m ² / g has poor dispersibility, increases hysteresis loss, and has low fuel consumption. Tends to decrease.
In addition, the nitrogen adsorption specific surface area by the BET method of a silica can be measured by the method based on ASTM D3037-81.

The content of silica is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 150 parts by mass or less, more preferably 100 parts by mass or less, with respect to 100 parts by mass of the rubber component. . If the silica content is less than 5 parts by mass, the wear resistance tends to be insufficient. On the other hand, if the silica content exceeds 150 parts by mass, the silica is difficult to disperse, and the workability and fuel efficiency are low. There is a tendency to get worse.

(Silane coupling agent)
In the present invention, it is preferable to use a silane coupling agent together with silica. The silane coupling agent is not particularly limited, and those conventionally used in the tire field can be used. For example, sulfide-based, mercapto-based, vinyl-based, amino-based, glycidoxy-based, nitro-based, chloro-based silane coupling Agents and the like. Among them, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, etc. A sulfide system can be preferably used. Bis (3-triethoxysilylpropyl) tetrasulfide and 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide are particularly preferable from the viewpoint of reinforcing effect. These silane coupling agents may be used alone or in combination of two or more.

The content of the silane coupling agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more with respect to 100 parts by mass of silica. When the content of the silane coupling agent is less than 1 part by mass, the viscosity of the unvulcanized rubber composition tends to be high, and the processability tends to deteriorate. Further, the content of the silane coupling agent is preferably 20 parts by mass or less, more preferably 15 parts by mass or less with respect to 100 parts by mass of silica. When the content of the silane coupling agent exceeds 20 parts by mass, the blending effect of the silane coupling agent as much as the content cannot be obtained, and the cost tends to be high.

(Anti-aging agent)
The rubber composition of the present invention can contain an anti-aging agent. As the anti-aging agent, amine-based, phenol-based, and imidazole-based compounds, carbamic acid metal salts, waxes, and the like can be appropriately selected and used.

(Softener)
The rubber composition of the present invention can contain a softening agent. Examples of the softener include petroleum softeners, fatty oil softeners, fatty acids and the like. The content of the softening agent is preferably 100 parts by mass or less with respect to 100 parts by mass of the rubber component because there is little risk of reducing wet grip performance.

(Vulcanizing agent)
The rubber composition of the present invention can contain a vulcanizing agent. As the vulcanizing agent, an organic peroxide, a sulfur vulcanizing agent, or the like can be used. Of these, sulfur-based vulcanizing agents are preferable and sulfur is more preferable from the viewpoint that the effects of the present invention can be obtained satisfactorily.

(Vulcanization accelerator)
The rubber composition of the present invention can contain a vulcanization accelerator. Examples of the vulcanization accelerator include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, and xanthate vulcanization accelerators. Is mentioned. These may be used alone or in combination of two or more.

(Vulcanization aid)
The rubber composition of the present invention can contain a vulcanization aid. As the vulcanization aid, stearic acid, zinc oxide (zinc white) or the like can be used.

(Other ingredients)
In the rubber composition of the present invention, various reinforcing agents, various oils, plasticizers, coupling agents, etc., various compounding agents and additives compounded for tires or general rubber compositions can be blended. . Moreover, the content of these compounding agents and additives can also be set to general amounts.

<Method for producing rubber composition>
The rubber composition of the present invention can be produced by a conventionally known production method, and the production method is not limited. For example, it can be produced by kneading each of the above components using a kneading machine such as a Banbury mixer or a kneading roll under ordinary methods and conditions.

By using the rubber composition of the present invention thus obtained, a pneumatic tire having improved fuel economy and wet grip performance in a well-balanced manner can be obtained. The rubber composition can be used for each member of a tire, and in particular, can be suitably used for a tread, a sidewall, and the like.

<Pneumatic tire>
The pneumatic tire of the present invention is produced by a usual method using the rubber composition.
That is, by extruding a rubber composition containing the above components in accordance with the shape of a tread or the like at an unvulcanized stage, and molding it with a tire molding machine by a normal method along with other tire members, Form an unvulcanized tire. The unvulcanized tire is heated and pressurized in a vulcanizer to obtain a pneumatic tire.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Hereinafter, various chemicals used at the time of synthesis and polymerization will be described together. In addition, the chemical | medical agent refine | purified according to the usual method as needed.
DMF: N, N-dimethylformamide sodium hydride manufactured by Kanto Chemical Co., Ltd .: Triethylene glycol monobutyl ether manufactured by Kanto Chemical Co., Ltd .: 4-chloromethylstyrene manufactured by Kanto Chemical Co., Ltd .: manufactured by Wako Pure Chemical Industries, Ltd. Octaethylene glycol monobutyl ether: Aldrich Toluene: Kanto Chemical Co., Ltd. 4-vinylbenzaldehyde: Sigma Aldrich Co., Ltd. 1-butanol: Kanto Chemical Co., Ltd. p-Toluenesulfonic acid: Kanto Chemical Co., Ltd. t- Butylcatechol: Kanto Chemical Co., Ltd. ethylene glycol: Kanto Chemical Co., Ltd. n-hexane: Kanto Chemical Co., Ltd. Styrene: Kanto Chemical Co., Ltd. 1,3-butadiene: Tokyo Chemical Industry Co., Ltd. Tetra Methylethylenediamine: n-butyllithium manufactured by Kanto Chemical Co., Ltd .: 1.6M n-butyl manufactured by Kanto Chemical Co., Ltd. Cyllithium hexane solution 2,6-di-tert-butyl-p-cresol: Nocrack 200 manufactured by Ouchi Shinsei Chemical Co., Ltd.
Denaturant (1): 3- (N, N-dimethylamino) propyltrimethoxysilane manufactured by AMAX Co., Ltd. Modifier (2): 3-glycidoxypropyltrimethoxysilane manufactured by AMAX Co., Ltd.

<Synthesis of Compound Represented by General Formula (I)>
(Compound A)
To a three-necked flask thoroughly purged with nitrogen, 100 mL of DMF and 1.8 g of sodium hydride were added, and 13 g of triethylene glycol monobutyl ether was added dropwise at 0 ° C. After stirring at room temperature for 1 hour, it was cooled again to 0 ° C., 7.5 g of 4-chloromethylstyrene was added dropwise, and the mixture was stirred as it was for 1 hour. A saturated aqueous ammonium chloride solution was added to the resulting solution, and purification was performed by extraction, concentration, and column purification to obtain Compound A represented by the following structural formula. (R ¹ = methylene group, R ² = ethylene group, R ³ = n-butyl group, r = 3)

(Compound B)
Compound B represented by the following structural formula was obtained by the same formulation as Compound A except that 22 g of octaethylene glycol monobutyl ether was added instead of triethylene glycol monobutyl ether. (R ¹ = methylene group, R ² = ethylene group, R ³ = n-butyl group, r = 8)

<Synthesis of Compound Represented by General Formula (II)>
(Compound C)
100 mL of toluene, 5.3 g of 4-vinylbenzaldehyde, 8.9 g of 1-butanol, 5 mg of p-toluenesulfonic acid and 1 mg of t-butylcatechol were added to a three-necked flask thoroughly purged with nitrogen, and refluxed at 110 ° C. for 2 hours. I let you. Thereafter, the resulting solution was washed with an aqueous sodium hydrogen carbonate solution, dried over magnesium sulfate, filtered, concentrated, and further purified by distillation under reduced pressure to obtain compound C (4-vinylbenzaldehyde dibutyl acetal) represented by the following structural formula. Obtained. (R ⁴ , R ⁵ = n-butyl group, R ⁶ = hydrogen atom)

(Compound D)
Compound D (4-vinylbenzaldehyde ethylene acetal) represented by the following structural formula was obtained by the same formulation as Compound C, except that 4.1 g of ethylene glycol was added instead of 1-butanol. (R ⁴ , R ⁵ = linked ethylene group, R ⁶ = hydrogen atom)

<Analysis of copolymer>
The copolymer obtained as described below was analyzed by the following method.

(Measurement of weight average molecular weight Mw)
The weight average molecular weight Mw of the copolymer is a gel permeation chromatograph (GPC) (GPC-8000 series manufactured by Tosoh Corp., detector: differential refractometer, column: TSKGEL SUPERMALTPORE HZ-M manufactured by Tosoh Corp.) It calculated | required by standard polystyrene conversion based on the measured value by.

(Structural identification of copolymer)
The structure of the copolymer was identified using a JNM-ECA series device manufactured by JEOL Ltd. From the measurement results, the contents of Compound A, Compound B, Compound C, Compound D, styrene, and 1,3-butadiene in the copolymer were calculated.

<Synthesis of copolymer>
(Copolymer (1))
To a pressure-resistant container sufficiently substituted with nitrogen, add 1500 mL of n-hexane, 10.4 g of styrene, 43.2 g of 1,3-butadiene, 0.27 g of compound A, 0.2 mmol of tetramethylethylenediamine, and 0.12 mmol of n-butyllithium, Stir at 0 ° C. for 48 hours. Thereafter, alcohol was added to stop the reaction, 1 g of 2,6-tert-butyl-p-cresol was added to the reaction solution, and then copolymer (1) was obtained by reprecipitation purification. As a result of the analysis, Mw was 480000, Compound A content was 0.5 mass%, and styrene content was 20 mass%.

(Copolymer (2))
A copolymer (2) was obtained by the same formulation as the copolymer (1) except that 0.27 g of the compound B was added instead of the compound A. As a result of analysis, Mw was 500,000, Compound B content was 0.5 mass%, and styrene content was 21 mass%.

(Copolymer (3))
A copolymer (3) was obtained by the same formulation as the copolymer (1) except that 0.16 g of compound A was added. As a result of analysis, Mw was 460000, Compound A content was 0.3% by mass, and styrene content was 21% by mass.

(Copolymer (4))
A copolymer (4) was obtained by the same formulation as the copolymer (1) except that 0.81 g of compound A was added. As a result of the analysis, Mw was 520000, Compound A content was 1.5% by mass, and styrene content was 16% by mass.

(Copolymer (5))
A copolymer (5) was obtained by the same formulation as the copolymer (1) except that styrene was not added. As a result of analysis, Mw was 560000 and the content of Compound A was 0.6% by mass.

(Copolymer (6))
A copolymer (6) was obtained by the same formulation as the copolymer (1) except that 8 mmol of tetramethylethylenediamine and 5 mmol of n-butyllithium were added. As a result of the analysis, Mw was 20000, Compound A content was 0.5% by mass, and styrene content was 20% by mass.

(Copolymer (7))
To a heat-resistant container sufficiently purged with nitrogen, 1500 mL of n-hexane, 100 mmol of styrene, 800 mmol of 1,3-butadiene, 0.2 mmol of tetramethylethylenediamine, and 0.12 mmol of n-butyllithium were added and stirred at 0 ° C. for 48 hours. Thereafter, alcohol was added to stop the reaction, and 1 g of 2,6-di-tert-butyl-p-cresol was added to the reaction solution, followed by reprecipitation purification to obtain a copolymer (7). As a result of the analysis, Mw was 470000 and the styrene content was 19% by mass.

(Copolymer (8))
Add 1500 mL of n-hexane, 100 mmol of styrene, 800 mmol of 1,3-butadiene, 5 mmol of compound A, 0.2 mmol of tetramethylethylenediamine, 0.12 mmol of n-butyllithium to a heat-resistant container sufficiently substituted with nitrogen, and stir at 0 ° C. for 48 hours. did. Thereafter, 0.15 mmol of the modifying agent (1) was added and stirred at 0 ° C. for 1 hour. Thereafter, alcohol was added to stop the reaction, and 1 g of 2,6-di-tert-butyl-p-cresol was added to the reaction solution, and then copolymer (8) was obtained by reprecipitation purification. As a result of analysis, Mw was 500,000, Compound A content was 1.2% by mass, and styrene content was 19% by mass.

(Copolymer (9))
A copolymer (9) was obtained by the same formulation as the copolymer (8) except that the modifier (2) was added instead of the modifier (1). As a result of analysis, Mw was 490000, Compound A content was 1.3% by mass, and styrene content was 18% by mass.

(Copolymer (10))
A copolymer (10) was obtained by the same formulation as the copolymer (8) except that 1 mmol of the compound A was added. As a result of analysis, Mw was 460000, Compound A content was 0.3% by mass, and styrene content was 21% by mass.

(Copolymer (11))
Instead of compound A, copolymer (11) was obtained by the same formulation as copolymer (8) except that 5 mmol of compound B was added. As a result of analysis, Mw was 510000, Compound B content was 1.4% by mass, and styrene content was 19% by mass.

(Copolymer (12))
A copolymer (12) was obtained by the same formulation as the copolymer (8) except that styrene was not added. As a result of the analysis, Mw was 560000 and the content of Compound A was 1.6% by mass.

(Copolymer (13))
A copolymer (13) was obtained by the same formulation as the copolymer (8) except that 8 mmol of tetramethylethylenediamine and 5 mmol of n-butyllithium were added. As a result of the analysis, Mw was 20000, Compound A content was 1.2% by mass, and styrene content was 20% by mass.

(Copolymer (14))
Add 1500 ml of n-hexane, 100 mmol of styrene, 800 mmol of 1,3-butadiene, 2.5 mmol of compound A, 2.5 mmol of compound C, 0.2 mmol of tetramethylethylenediamine, 0.12 mmol of n-butyllithium to a heat-resistant container sufficiently substituted with nitrogen. And stirred at 0 ° C. for 48 hours. Thereafter, alcohol was added to stop the reaction, 1 g of 2,6-tert-butyl-p-cresol was added to the reaction solution, and then copolymer (14) was obtained by reprecipitation purification. As a result of analysis, Mw was 500,000, Compound A content was 0.9% by mass, Compound C content was 0.7% by mass, and styrene content was 19% by mass.

(Copolymer (15))
Instead of compound C, copolymer (15) was obtained by the same formulation as copolymer (14) except that 2.5 mmol of compound D was added. As a result of the analysis, Mw was 510000, Compound A content was 0.9% by mass, Compound D content was 0.7% by mass, and styrene content was 19% by mass.

(Copolymer (16))
Instead of compound A, copolymer (16) was obtained by the same formulation as copolymer (15) except that 2.5 mmol of compound B was added. As a result of analysis, Mw was 510000, Compound B content was 1.4% by mass, Compound D content was 0.7% by mass, and styrene content was 19% by mass.

(Copolymer (17))
A copolymer (17) was obtained by the same formulation as the copolymer (14) except that styrene was not added. As a result of the analysis, Mw was 520000, Compound A content was 0.9% by mass, and Compound C content was 0.7% by mass.

(Copolymer (18))
A copolymer (18) was obtained by the same formulation as the copolymer (14) except that 8 mmol of tetramethylethylenediamine and 5 mmol of n-butyllithium were added. As a result of analysis, Mw was 20000, compound A content was 0.9% by mass, compound C content was 0.7% by mass, and styrene content was 20% by mass.

(Copolymer (19))
To a heat-resistant container sufficiently substituted with nitrogen, add 1500 mL of n-hexane, 100 mmol of styrene, 800 mmol of 1,3-butadiene, 2.5 mmol of compound A, 2.5 mmol of compound C, 0.2 mmol of tetramethylethylenediamine, and 0.12 mmol of n-butyllithium. And stirred at 0 ° C. for 48 hours. Thereafter, 0.15 mmol of the modifying agent (1) was added and stirred at 0 ° C. for 1 hour. Thereafter, alcohol was added to stop the reaction, and 1 g of 2,6-di-tert-butyl-p-cresol was added to the reaction solution, followed by reprecipitation purification to obtain a copolymer (19). As a result of analysis, Mw was 500,000, Compound A content was 0.7% by mass, Compound C content was 0.7% by mass, and styrene content was 19% by mass.

(Copolymer (20))
A copolymer (20) was obtained by the same formulation as the copolymer (19) except that the modifier (2) was added instead of the modifier (1). As a result of analysis, Mw was 490000, Compound A content was 0.7% by mass, Compound C content was 0.8% by mass, and styrene content was 20% by mass.

(Copolymer (21))
Instead of compound C, copolymer (21) was obtained by the same formulation as copolymer (19) except that 2.5 mmol of compound D was added. As a result of analysis, Mw was 460000, Compound A content was 0.7% by mass, Compound D content was 0.5% by mass, and styrene content was 20% by mass.

(Copolymer (22))
Instead of compound A, copolymer (22) was obtained by the same formulation as copolymer (21) except that 2.5 mmol of compound B was added. As a result of analysis, Mw was 500,000, Compound B content was 0.7% by mass, Compound D content was 0.6% by mass, and styrene content was 19% by mass.

(Copolymer (23))
A copolymer (23) was obtained by the same formulation as the copolymer (19) except that styrene was not added. As a result of analysis, Mw was 560000, Compound A content was 0.9% by mass, and Compound C content was 0.8% by mass.

(Copolymer (24))
A copolymer (24) was obtained by the same formulation as the copolymer (19) except that 8 mmol of tetramethylethylenediamine and 5 mmol of n-butyllithium were added. As a result of the analysis, Mw was 20000, Compound A content was 0.8% by mass, Compound C content was 1.1% by mass, and styrene content was 20% by mass.

The monomer components, modifiers, and weight average molecular weight Mw of the copolymers (1) to (24) are summarized in Table 1.

<Examples and Comparative Examples>
Below, various chemical | medical agents used by the Example and the comparative example are demonstrated.
NR: RSS # 3
BR: Ubepol BR150B manufactured by Ube Industries, Ltd.
SBR: SL574 manufactured by JSR Corporation
Copolymers (1) to (24): Synthetic silica by the above method: Ultrasil VN3 (N ₂ SA: 175 m ² / g) manufactured by Degussa
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa
Anti-aging agent: NOCRACK 6C (N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Stearic acid: Zinc stearate manufactured by NOF Corporation: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur vulcanization accelerator manufactured by Tsurumi Chemical Co., Ltd. (1): Ouchi Shinsei Chemical Noxeller CZ made by Kogyo Co., Ltd.
Vulcanization accelerator (2): Noxeller D manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

According to the formulation shown in Tables 2 to 5, the chemicals were kneaded and blended to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was press vulcanized at 170 ° C. for 15 minutes to obtain a vulcanized rubber composition.
Further, the unvulcanized rubber composition is formed into a tread shape and bonded together with other tire members to form an unvulcanized tire, press vulcanized at 170 ° C. for 10 minutes, and a test tire ( Size 195 / 65R15) was produced.
The resulting vulcanized rubber composition and test tire were evaluated for fuel economy and wet grip performance by the following test methods.

<Evaluation items and test methods>
(Low fuel consumption)
The obtained vulcanized rubber composition was measured for tan δ at a dynamic strain amplitude of 1%, a frequency of 10 Hz, and a temperature of 50 ° C. using a spectrometer manufactured by Ueshima Seisakusho. And the measurement result was displayed as an index according to the following formula. The larger the index, the lower the rolling resistance and the better the fuel efficiency.
(Low fuel consumption index) = (tan δ of Comparative Example 1) / (tan δ of each formulation) × 100

(Wet grip performance (1))
Wet grip performance was evaluated using a flat belt friction tester (FR5010 type) manufactured by Ueshima Seisakusho. A cylindrical rubber test piece having a width of 20 mm and a diameter of 100 mm made of the above vulcanized rubber composition was used as a sample, and the slip ratio of the sample with respect to the road surface was 0 to 0 at a speed of 20 km / hour, a load of 4 kgf, and a road surface temperature of 20 ° C. The maximum value of the friction coefficient detected at that time was read up to 70%. And the measurement result was displayed as an index according to the following formula. A larger index indicates better wet grip performance.
(Wet grip performance (1) index) = (maximum friction coefficient of each formulation) / (maximum friction coefficient of Comparative Example 1) × 100

(Wet grip performance (2))
On a test course with wet water and wet road surface, the test tire is mounted on a 2000 cc domestic FR vehicle, braked at a speed of 70 km / h, and the distance traveled between braking the tire and stopping (Brake distance) was measured. And the measurement result was displayed as an index according to the following formula. A larger index indicates better wet grip performance.
(Wet grip performance (2) index) = (braking distance of comparative example 1) / (braking distance of each formulation) × 100

As shown in Tables 2 to 5, it contains a copolymer obtained by copolymerizing 1,3-butadiene and the compound represented by the above general formula (I) and having a weight average molecular weight Mw within a specific range. The fuel efficiency and wet grip performance of the example were improved in a well-balanced manner as compared with the comparative example.

Claims (14)

It is obtained by copolymerizing 1,3-butadiene and a compound represented by the following general formula (I),
A copolymer having a weight average molecular weight Mw of 1.0 × 10 ^{5 to} 2.5 × 10 ⁶ .

^(Wherein, R 1 to R ³ are, .r representing the hydrocarbon radical is an integer.) The copolymer of Claim 1 obtained by copolymerizing the compound represented by the following general formula (II) with the compound represented by the said 1,3-butadiene and the said general formula (I) at least.

(In the formula, R ⁴ and R ⁵ represent a hydrocarbon group. R ⁴ and R ⁵ may be bonded to each other. R ⁶ represents a hydrogen atom or a hydrocarbon group.) The copolymer according to claim 1 or 2, wherein the terminal is modified with a modifier having a functional group containing at least one atom selected from the group consisting of nitrogen, oxygen and silicon. The copolymer according to any one of claims 1 to 3, obtained by copolymerizing styrene together with at least the 1,3-butadiene and the compound represented by the general formula (I). The copolymer according to any one of claims 1 to 4, wherein, in the general formula (I), the hydrocarbon group represented by R ¹ , R ^2, and R ³ has 1 to 10 carbon atoms. In said general formula (I), r is an integer of 1-30, The copolymer in any one of Claims 1-5. The copolymer of Claim 2 whose carbon number of the hydrocarbon group represented by R < ⁴ >, R < ⁵ > and R < ⁶ > is 1-10 in the said general formula (II). Content of the compound represented by the said general formula (I) is 0.05-35 mass%, The copolymer in any one of Claims 1-7. The copolymer according to claim 2 or 7, wherein the content of the compound represented by the general formula (II) is 0.05 to 35% by mass. The copolymer according to claim 3, wherein the modifier is a compound represented by the following general formula (III) or the following general formula (IV).

(Wherein R ⁷ , R ⁸ and R ⁹ are the same or different and each represents an alkyl group, an alkoxy group, a silyloxy group, a carboxyl group, a mercapto group, or a derivative thereof. R ¹⁰ and R ¹¹ are the same or different. And represents a hydrogen atom or an alkyl group, and n represents an integer.)

(In formula, R <^12> , R <^13> and R < ¹⁴ > are the same or different, and represent an alkyl group, an alkoxy group, a silyloxy group, a carboxyl group, a mercapto group, or derivatives thereof. R < ¹⁵ > represents a cyclic ether group. p and q represent integers.) The rubber composition containing the copolymer in any one of Claims 1-10. The rubber composition according to claim 11, wherein the content of the copolymer is 3% by mass or more in 100% by mass of the rubber component. The rubber composition according to claim 11 or 12, comprising 5 to 150 parts by mass of silica with respect to 100 parts by mass of the rubber component. The pneumatic tire produced using the rubber composition in any one of Claims 11-13.