JP2011132411A - Rubber composition for tire and pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition, improved, with excellent balance, in characteristics for low fuel consumption, destruction characteristics (abrasion resistance) and wet-grip characteristics, and to provide a pneumatic tire formed of the rubber composition. <P>SOLUTION: The rubber composition includes: a rubber component containing a modified conjugated diene based polymer having a functional group containing hetero atoms at a main chain and at least at one of terminals; and silica; wherein the amount of the silica is 10-200 pts.mass for 100 pts.mass of the rubber component; and the amount of a silane coupling agent contained is at most 3 pts.mass for 100 pts.mass of silica. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a rubber composition for a tire and a pneumatic tire using the same.

In recent years, from the standpoints of resource saving, energy saving, and environmental protection, social demands for reducing carbon dioxide emissions have increased, and reduction of carbon dioxide emissions is also desired for automobiles. Therefore, it is necessary to improve fuel efficiency by improving rolling resistance of automobile tires, and further, there is an increasing demand for improving safety during driving. Since the fuel efficiency and safety depend largely on the performance of the tire used, there is an increasing demand for improvement in fuel efficiency, steering stability (dry grip performance, wet grip performance, etc.) and durability for the tire.

These tire characteristics depend on various factors such as the structure of the tire and the materials used, but the tires are particularly low in fuel consumption, handling stability, and durability in terms of the performance of the rubber composition used in the tread portion in contact with the road surface. Greatly contributes to properties. For this reason, many technical improvements of rubber compositions for tire treads have been studied, proposed, and put into practical use.

The tire tread rubber is required to have low hysteresis loss (improvement of fuel efficiency), high durability and high wear resistance, and the like. However, the relationship between low hysteresis loss and fracture characteristics is contradictory, and at present, it is difficult to solve the problem by improving the performance. Silica is widely used as a filler in order to improve the balance between fuel efficiency and fracture characteristics. However, when silica is used, kneading is difficult, and improving the dispersibility and workability of silica is an issue. It has become.

Patent Document 1 contains a conjugated diene polymer or conjugated diene-aromatic vinyl copolymer whose molecular chain terminal is modified with a specific functional group as a tire rubber composition that can improve grip performance and wear resistance performance. Techniques to do this are disclosed. However, there is still room for improvement in terms of improving fuel economy and destruction characteristics in a well-balanced manner. In addition to these performances, it is also required to improve the wet grip performance in a well-balanced manner.

JP 2009-161648 A

The present invention solves the above-mentioned problems, and provides a tire rubber composition that can improve fuel economy, fracture characteristics (such as wear resistance), and wet grip performance in a well-balanced manner, and a pneumatic tire using the rubber composition. The purpose is to provide.

The present invention contains a rubber component containing a modified conjugated diene polymer having a hetero atom-containing functional group at the main chain and at least one terminal, and silica, and the silica content is 100 parts by mass of the rubber component. It is 10-200 mass parts with respect to this, It is related with the rubber composition for tires whose content of the said silane coupling agent is 3 mass parts or less with respect to 100 mass parts of silica.

The modified conjugated diene polymer is obtained by reacting a compound having a monomer unit having a heteroatom-containing functional group in the main chain and having a heteroatom-containing functional group at least at one end. preferable.

（式中、Ｘは、ヘテロ原子含有官能基を表す。） The monomer unit having a hetero atom-containing functional group is preferably a unit derived from a monomer represented by the following formula (I).

(In the formula, X represents a heteroatom-containing functional group.)

The hetero atom-containing functional group is preferably an alkyl-substituted amino group, a cyclic amino group, an alkoxy group or an alkoxysilyl group.
The content of the modified conjugated diene polymer is preferably 30% by mass or more in 100% by mass of the rubber component.

It is preferable that the rubber component further contains natural rubber and / or butadiene rubber.
The rubber composition is preferably used for a tread.
The present invention also relates to a pneumatic tire produced using the rubber composition.

According to the present invention, since the rubber composition for a tire contains a specific modified conjugated diene polymer and silica and the amount of the silane coupling agent is a predetermined amount or less, fuel efficiency, fracture characteristics, and wet grip performance are obtained. By using the rubber composition in the tread, a pneumatic tire excellent in these performances can be provided.

The rubber composition for tires of the present invention contains a rubber component containing a main chain and a modified conjugated diene polymer having a hetero atom-containing functional group at at least one terminal, and silica, and the amount of the silane coupling agent is Below a predetermined amount. By modifying the main chain of the conjugated diene polymer by copolymerizing a monomer having a heteroatom-containing functional group with a conjugated diene compound, etc., and reacting a compound having a heteroatom-containing functional group at the terminal. By modifying, it is possible to reduce hysteresis loss and improve fracture characteristics, and to achieve both performances. In addition, since wet grip performance can also be improved, it is possible to improve fuel economy, breaking characteristics, and wet grip performance in a well-balanced manner.

In the present invention, the reason why the above performance can be improved in a well-balanced manner as compared with the conventional method using both silica and a silane coupling agent is not clear, but is presumed as follows.
When silica and a silane coupling agent are used, a strong (covalent) bond is formed by the silica and the coupling agent. In addition, the reaction position between the polymer and the coupling agent cannot be controlled.
On the other hand, in the present invention, monomer units having a heteroatom-containing functional group are randomly introduced into the main chain at the time of polymer synthesis, so that the introduction position of the unit can be controlled and the introduced modified group (heteroatom-containing A relatively weak bond is formed between the functional group) and silica. For this reason, when the amount of deformation is small, the modifying group and silica are strongly bonded to reduce hysteresis loss. On the other hand, when the amount of deformation is large, the bonding point of the modifying group and silica moves, and the elongation at break is increased. Since the performance of is improved, the fracture characteristics are improved. That is, it is presumed that both low fuel consumption and fracture characteristics can be achieved by changing the bonding force between the modifying group and silica according to the amount of deformation. Moreover, since the favorable dispersibility of a silica is obtained, it is estimated that the outstanding wet grip performance is also obtained simultaneously.

<Rubber component>
(Modified conjugated diene copolymer)
In the present specification, the “modified conjugated diene copolymer” is a concept included in the rubber component.
The modified conjugated diene polymer used as the rubber component (modified conjugated diene polymer modified at the main chain and terminal) has, for example, a monomer unit having a hetero atom-containing functional group in the main chain ( Suitable is a polymer in which a monomer unit having a heteroatom-containing functional group is introduced in the main chain) and a compound having a heteroatom-containing functional group is reacted at at least one terminal (polymerization terminal of the copolymer). Used for.

The modified conjugated diene polymer is, for example, a conjugate in which a main chain obtained by copolymerization of a monomer having a hetero atom-containing functional group, a conjugated diene compound, and a vinyl aromatic compound as necessary is modified. It can be obtained by reacting a compound having a heteroatom-containing functional group at the active end of the diene polymer (a compound containing a heteroatom in the molecule). Thereby, a monomer unit having a hetero atom-containing functional group (unit derived from the monomer) in the main chain and further having a hetero atom-containing functional group at the terminal is added. .

The monomer having a hetero atom-containing functional group is not particularly limited as long as it is a monomer having the functional group, but a monomer represented by the following formula (I) is preferable. In this case, since the unit derived from the monomer can be suitably introduced into the main chain, the functional group is also suitably introduced at a desired position, so that the effects of the present invention can be suitably obtained. When the monomer is used, the modified conjugated diene polymer has the monomer unit derived from the monomer having the hetero atom-containing functional group in the main chain. The modified conjugated diene copolymer may contain one hetero atom-containing functional group or two or more hetero atom-containing functional groups in the main chain.

（式中、Ｘはヘテロ原子含有官能基を表す。）

(In the formula, X represents a hetero atom-containing functional group.)

The heteroatom-containing functional group represented by X is not particularly limited as long as it is a functional group containing a heteroatom such as nitrogen, oxygen, sulfur, etc. Among them, an alkyl-substituted amino group, cyclic amino group, alkoxy group, alkoxysilyl Groups are preferred. In this case, fuel economy, destruction characteristics, and wet grip performance can be improved in a well-balanced manner.

Examples of the alkyl-substituted amino group include a monoalkyl-substituted amino group and a dialkyl-substituted amino group, and the substituted alkyl group in the alkyl-substituted amino group may be further substituted with a halogen atom or the like. Of these, a dialkyl-substituted amino group is preferable. Carbon number of a substituted alkyl group becomes like this. Preferably it is 1-20, More preferably, it is 1-10, More preferably, it is 1-4. The substituted alkyl group may be linear, branched or cyclic.

Examples of the alkyl-substituted amino group include dimethylamino group, diethylamino group, dipropylamino group, dibutylamino group, dipentylamino group, dihexylamino group, diheptylamino group, dioctylamino group, dinonylamino group, didecylamino group, diundecyl. Amino group, didodecylamino group, ditridecylamino group, ditetradecylamino group, dipentadecylamino group, dicyclopentylamino group, dicyclohexylamino group, dicycloheptylamino group, dicyclooctylamino group, dicyclononylamino Group, N, N-methylethylamino group, N, N-methylpropylamino group, N, N-methylbutylamino group, N, N-ethylpropylamino group, N, N-ethylbutylamino group, N, N -Ethyloctylamino group, N, N-methyl Cyclopentylamino group, N, N-methylcyclohexylamino group, N, N-methylheptylamino group, N, N-ethylcyclopentylamino group, N, N-ethylcyclohexylamino group, N, N-propylcyclopentylamino group, N , N-propylcyclohexylamino group, N, N-butylcyclopentylamino group, N, N-butylcyclohexylamino group and the like. Of these, a dimethylamino group, a diethylamino group, and a dipropylamino group are preferable from the viewpoint of performance improvement effect and low cost.

（式中、Ａは、炭素数３〜１６のアルキレン基、置換アルキレン基を表す。）
Ａの置換アルキレン基において、置換基としては、炭素数１〜１２の直鎖状又は分岐状アルキル基、シクロアルキル基などが挙げられる。Ａの具体例としては、トリメチレン基、テトラメチレン基、ヘキサメチレン基、ヘプタメチレン基、オクタメチレン基などが挙げられる。なかでも、Ａとしては、性能改善効果の観点から、テトラメチレン基、ヘキサメチレン基、ヘプタメチレン基が好ましい。 Examples of the cyclic amino group include groups represented by the following formulas.

(In the formula, A represents an alkylene group having 3 to 16 carbon atoms or a substituted alkylene group.)
In the substituted alkylene group of A, examples of the substituent include a linear or branched alkyl group having 1 to 12 carbon atoms and a cycloalkyl group. Specific examples of A include trimethylene group, tetramethylene group, hexamethylene group, heptamethylene group, octamethylene group and the like. Among these, as A, a tetramethylene group, a hexamethylene group, and a heptamethylene group are preferable from the viewpoint of a performance improvement effect.

As an alkoxy group, a C1-C20 (preferably 1-10, more preferably 1-4) alkoxy group is mentioned, Specifically, a methoxy group, an ethoxy group, n-propoxy group, n-butoxy group , Isobutoxy group, sec-butoxy group, tert-butoxy group, hexoxy group, octoxy group and the like. Of these, a methoxy group, an ethoxy group, an n-propoxy group, and a tert-butoxy group are preferable from the viewpoint of performance improvement effect and low cost.

Examples of the alkoxysilyl group include a monoalkoxysilyl group, a dialkoxysilyl group, and a trialkoxysilyl group. Of these, a dialkoxysilyl group is preferable, and a trialkoxysilyl group is more preferable. Examples of the alkoxy group in the alkoxysilyl group include the above alkoxy groups. Specific examples of the alkoxysilyl group include monomethoxysilyl group, monoethoxysilyl group, monopropoxysilyl group, monobutoxysilyl group, dimethoxysilyl group, diethoxysilyl group, dipropoxysilyl group, dibutoxysilyl group, trimethoxy A silyl group, a triethoxysilyl group, a tripropoxysilyl group, a tributoxysilyl group, etc. are mentioned. Among them, from the viewpoint of storage stability, availability, and performance improvement effect, monoethoxysilyl group, monopropoxysilyl group, monobutoxysilyl group, diethoxysilyl group, dipropoxysilyl group, dibutoxysilyl group, triethoxy A silyl group, a tripropoxysilyl group, and a tributoxysilyl group are preferable.

Among the monomers represented by the formula (I), monomers represented by the following formulas (I-1) to (I-3) are more preferable, and the following formulas (I-1) and (I -2) is more preferable, and a monomer represented by the following formula (I-2) is particularly preferable.

（式（Ｉ−１）中、ＮＲ_２は前記アルキル置換アミノ基、前記環状アミノ基と同様。式（Ｉ−２）中、ＯＲは前記アルコキシ基と同様。式（Ｉ−３）中、Ｓｉ（ＯＲ）_３は前記トリアルコキシシリル基と同様。）
なお、上記式（Ｉ−１）〜（Ｉ−３）におけるアルキル置換アミノ基、環状アミノ基、アルコキシ基、トリアルコキシシリル基の好適な基は前述と同様である。また、上記式（Ｉ−１）におけるアルキル置換アミノ基や環状アミノ基は、パラ位に結合していることが好ましい。

(In formula (I-1), NR ₂ is the same as the alkyl-substituted amino group and cyclic amino group. In formula (I-2), OR is the same as the alkoxy group. In formula (I-3), Si is (OR) ₃ is the same as the trialkoxysilyl group.)
In the above formulas (I-1) to (I-3), suitable groups for the alkyl-substituted amino group, cyclic amino group, alkoxy group and trialkoxysilyl group are the same as described above. In addition, the alkyl-substituted amino group or cyclic amino group in the above formula (I-1) is preferably bonded to the para position.

Examples of the conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, and the like. Among these, 1,3-butadiene is particularly preferable. On the other hand, examples of the vinyl aromatic compound include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene, and the like. Of these, styrene is preferred. These monomers may be used alone or in combination of two or more.

Examples of the modified conjugated diene polymer include a copolymer of the monomer having a hetero atom-containing functional group, a conjugated diene compound, and a vinyl aromatic compound, and the monomer having a hetero atom-containing functional group and a conjugated diene. A copolymer with a compound is preferred. These copolymers are more preferably those using 1,3-butadiene as the conjugated diene compound.

When a conjugated diene polymer having an active end is produced by anionic polymerization during the copolymerization of the modified conjugated diene polymer, an organic alkali metal compound is preferably used as the polymerization initiator, and a lithium compound is used. Is more preferable. Examples of the lithium compound include hydrocarbyl lithium and lithium amide compounds. When hydrocarbyl lithium is used as the polymerization initiator, a polymer having a hydrocarbyl group at the polymerization initiation terminal and the other terminal being the active terminal is obtained. On the other hand, when a lithium amide compound is used as the polymerization initiator, a polymer having a nitrogen-containing functional group at the polymerization initiation terminal and the other terminal being the active terminal is obtained, and the polymer is heterogeneous at the other terminal. Even if the compound having an atom-containing functional group is not reacted, it can be used as a modified conjugated diene polymer having a modified main chain and terminal in the present invention. That is, the modified conjugated diene polymer in the present invention has a monomer unit having a heteroatom-containing functional group in the main chain and a heteroatom-containing functional group derived from a polymerization initiator at the polymerization initiation terminal. There may be. In addition, the usage-amount of a polymerization initiator has the preferable range of 0.2-20 mmol per 100g of monomers.

Examples of the hydrocarbyl lithium include ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, and 2-butyl-phenyl. Examples include lithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclopentyllithium, reaction products of diisopropenylbenzene and butyllithium, and among these, ethyllithium, n-propyllithium, isopropyllithium, n-butyl Alkyl lithium such as lithium, sec-butyl lithium, tert-octyl lithium and n-decyl lithium is preferable, and n-butyl lithium is particularly preferable.

On the other hand, the lithium amide compounds include lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium Dihexylamide, lithium diheptylamide, lithium dioctylamide, lythym-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiperazide, lithium ethylpropylamide, lithium ethylbutyramide, lithium methylbutyramide, lithium ethylbenzylamide, Lithium methyl phenethyl amide, etc., among which lithium hexamethylene imide, lithium pyrrolidide, lithium Umupiperijido, lithium heptamethylene imide, preferably lithium amide compound of the cyclic such as lithium dodecamethylene imide, lithium hexamethylene imide and lithium pyrrolidide are particularly preferable.

The method for producing a conjugated diene polymer by anionic polymerization using the above organic alkali metal compound or the like is not particularly limited. For example, in a hydrocarbon solvent inert to the polymerization reaction, a heteroatom-containing functional group is formed. A conjugated diene having at least a main chain modified by polymerizing a mixture of a monomer having a conjugated diene compound or a monomer having a hetero atom-containing functional group, a conjugated diene compound, and a vinyl aromatic compound A polymer can be produced. Here, as the hydrocarbon solvent inert to the polymerization reaction, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans-2-butene, cis -2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like. These may be used alone or in combination of two or more.

The anionic polymerization may be performed in the presence of a randomizer. The randomizer can control the microstructure of the conjugated diene compound. For example, the randomizer can control the 1,2-bond content of a butadiene unit in a polymer using butadiene as a monomer, or can be styrene as a monomer. And butadiene units of a copolymer using butadiene are randomized. Examples of the randomizer include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, bistetrahydrofurylpropane, triethylamine, pyridine, N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, 1 , 2-dipiperidinoethane, potassium t-amylate, potassium t-butoxide, sodium t-amylate and the like. The amount of these randomizers used is preferably in the range of 0.01 to 100 mol equivalent per 1 mol of the polymerization initiator.

The anionic polymerization may be carried out by any of solution polymerization, gas phase polymerization, and bulk polymerization. In the case of solution polymerization, the concentration of the monomer in the solution is preferably in the range of 5 to 40% by mass, A range of 10 to 30% by mass is more preferable. In addition, when using together a conjugated diene compound and a vinyl aromatic compound as a monomer, the range of 3-50 mass% is preferable, and the content rate of the vinyl aromatic compound in a monomer mixture is 5-45 mass%. The range of is more preferable. Further, the polymerization mode is not particularly limited, and may be batch type or continuous type.

The polymerization temperature of the anionic polymerization is preferably in the range of −10 to 150 ° C., more preferably in the range of −5 to 130 ° C. The polymerization can be carried out under a generated pressure, but it is usually preferred to carry out the polymerization under a pressure sufficient to keep the monomer used in a substantially liquid phase. Here, when the polymerization reaction is carried out under a pressure higher than the generated pressure, it is preferable to pressurize the reaction system with an inert gas. Moreover, it is preferable to use what removed reaction-inhibiting substances, such as water, oxygen, a carbon dioxide, and a protic compound, as raw materials, such as a monomer used for superposition | polymerization, a polymerization initiator, and a solvent.

Examples of modifiers that can be used in reacting (modifying) a compound having a heteroatom-containing functional group (heteroatom-containing modifier) with the conjugated diene polymer having an active terminal include amino groups, amide groups, and alkoxy groups. Examples include modifiers containing heteroatoms such as silyl group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, carboxyl group, hydroxyl group, nitrile group, and pyridyl group. Examples of the hetero atom-containing modifier include 3-glycidoxypropyltrimethoxysilane, (3-triethoxysilylpropyl) tetrasulfide, and 1- (4-N, N-dimethylaminophenyl) -1-phenylethylene. 1,1-dimethoxytrimethylamine, 1,2-bis (trichlorosilyl) ethane, 1,3,5-tris (3-triethoxysilylpropyl) isocyanurate, 1,3,5-tris (3-trimethoxysilyl) Propyl) 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-phenylpipera 1-glycidyl-4-methylpiperazine, 1-glycidyl-4-methylhomopiperazine, 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 -(Triethoxysilylethyl) pyridine, 2- (trimethoxysilylethyl) pyridine, 2- (2-pyridylethyl) thiopropyltrimethoxysilane, 2- (4-pyridylethyl) thiopropyltrimethoxysilane, 2,2 -Diethoxy-1,6-diaza-2-sila Crooctane, 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) aminopro Pyrtriethoxysilane, 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) Propyltrimethoxysilane, 3- (N-allylamino) propyltrimethoxysilane, 3,4-diaminobenzoic acid, 3-aminopropyldimethylethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3 -Aminopropyltris (methoxydiethoxy Silane, 3-aminopropyldiisopropylethoxysilane, 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-dimethylaminopropyl) diethoxymethylsilane, 3- (N, N-dimethylaminopropyl) triethoxysilane, 3- (N, N-dimethylaminopropyl) trimethoxysilane, 3-triethoxysilylpropyl anhydride Succinic acid, 3-triethoxysilylpropyl acetic anhydride, 3-triphenoxysilylpropyl succinic anhydride, 3-triphenoxysilylpropyl acetic anhydride, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-hexamethyleneiminopropyltriethoxy Silane, 3-mercaptopropyltrimethoxysilane, (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-tetramethylpiperidinyl Oxy, 4-aminobutyltriethoxysilane, 4-vinylpyridine, 4-morpholinoacetophenone, 4-morpholinobenzophenone, m-aminophenyltrimethoxysilane, N- (1,3-dimethylbutylidene) -3- (triethoxy Silyl) -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 -Aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -11-aminoundecyltriethoxysilane, N- (2-aminoethyl) -11-aminoundecyltrimethoxysilane, N- (2-aminoethyl) -3-amino Isobutylmethyldiethoxysilane, 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-l-oxopentyl] caprolactam, N- 5- (trimethoxysilyl) -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-diethoxysila Cyclopentane, Nn-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′-diethyl Aminobenzophenone, 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-ethylaminoisobutyltri Ethoxysilane, N-ethylaminoisobutylto Methoxysilane, N-ethylaminoisobutylmethyldiethoxysilane, N-oxydiethylene-2-benzothiazolesulfenamide, N-cyclohexylaminopropyltriethoxysilane, N-cyclohexylaminopropyltrimethoxysilane, N-methylaminopropylmethyl Dimethoxysilane, N-methylaminopropylmethyldiethoxysilane, N-vinylbenzylazacycloheptane, N-phenylpyrrolidone, N-phenylaminopropyltriethoxysilane, N-phenylaminopropyltrimethoxysilane, N-phenylaminomethyltri Ethoxysilane, N-phenylaminomethyltrimethoxysilane, n-butylaminopropyltriethoxysilane, n-butylaminopropyltrimethoxysilane, N-methyl Aminopropyltriethoxysilane, 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 , (Aminoethylamino) -3-isobutyldimethoxysilane, (aminoethylaminomethyl) phenethyltriethoxysilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, acrylic acid, diethyl adipate, acetamidopropyltrimeth Sisilane, aminophenyltrimethoxysilane, aminobenzophenone, ureidopropyltriethoxysilane, ureidopropyltrimethoxysilane, ethylene oxide, octadecyldimethyl (3-trimethoxysilylpropyl) ammonium chloride, glycidoxypropyltriethoxysilane, glycidoxypropyl Trimethoxysilane, glycerol tristearate, chlorotriethoxysilane, chloropropyltriethoxysilane, chloropolydimethylsiloxane, chloromethyldiphenoxysilane, diallyldiphenyltin, diethylaminomethyltriethoxysilane, diethylaminomethyltrimethoxysilane, diethyl (glycidyl) Amine, diethyldithiocarbamic acid 2-benzothiazoyl ester, diethoxy Chlorosilane, (cyclohexylaminomethyl) triethoxysilane, (cyclohexylaminomethyl) trimethoxysilane, diglycidylpolysiloxane, dichlorodiphenoxysilane, dicyclohexylcarbodiimide, divinylbenzene, diphenylcarbodiimide, diphenylcyanamide, diphenylmethane diisocyanate, diphenoxymethylchlorosilane , Dibutyldichlorotin, 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, tetramethoxysilane, triethoxyvinylsilane, tris (3-trimethoxysilylpropyl) cyanurate, triphenylphosphate, triphenoxychlorosilane, triphenoxymethylsilicon, triphenoxymethylsilane, carbon dioxide, bis (
Triethoxysilylpropyl) amine, bis (trimethoxysilylpropyl) amine, bis [3- (triethoxysilyl) propyl] ethylenediamine, bis [3- (trimethoxysilyl) propyl] ethylenediamine, 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 Luorange glycidyl ether, bis (methyldiethoxysilylpropyl) amine, bis (methyldimethoxysilylpropyl) -N-methylamine, hydroxymethyltriethoxysilane, vinyltris (2-ethylhexyloxy) silane, vinylbenzyldiethylamine, vinylbenzyldimethyl Amine, vinylbenzyltributyltin, vinylbenzylpiperidine, vinylbenzylpyrrolidine, pyrrolidine, phenylisocyanate, phenylisothiocyanate, (phenylaminomethyl) methyldimethoxysilane, (phenylaminomethyl) methyldiethoxysilane, phthalamide, hexamethylene Diisocyanate, benzylidene aniline, polydiphenylmethane diisocyanate, polydimethylsiloxane, methyl-4- Rijiruketon, methyl caprolactam, methyl triethoxysilane, methyltriphenoxysilane, lauryl thio acid methyl, silicon tetrachloride, and the like. Among these, 3- (N, N-dimethylamino) propyltrimethoxysilane, 3- (N, N-diethylaminopropyl) trimethoxysilane, and 3- (N, N-dimethylamino) in terms of performance improvement. Propyltriethoxysilane, 3- (N, N-diethylaminopropyl) triethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (4-pyridylethyl) triethoxysilane, N- (3-triethoxysilylpropyl) ) -4,5-dihydroimidazole, 1,3-dimethyl-2-imidazolidinone, silicon tetrachloride and the like are preferable.

The usage-amount of the said modifier is 0.1-3.0 mol normally with respect to 1 mol of organic alkali metal compounds of a polymerization initiator, and the range of 0.3-1.5 mol is preferable. Further, the modification reaction with the modifying agent is preferably performed by a solution reaction, and the solution may contain a monomer used at the time of polymerization. The reaction mode of the modification reaction is not particularly limited, and may be a batch type or a continuous type. Furthermore, the reaction temperature of the modification reaction is not particularly limited as long as the reaction proceeds, and the reaction temperature of the polymerization reaction may be employed as it is.

The content of the monomer having a hetero atom-containing functional group in the modified conjugated diene polymer is preferably 0.5% by mass or more, more preferably 0.7% by mass or more, and further preferably 1.0% by mass. That's it. The content is preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less, and particularly preferably 3% by mass or less. If it is less than 0.7% by mass, the effect of the present invention may not be obtained. On the other hand, when it exceeds 10 mass%, there exists a possibility that it may become high cost.
In addition, in this invention, content of the monomer which has a hetero atom containing functional group is measured by the method of the below-mentioned Example.

The weight average molecular weight Mw of the modified conjugated diene polymer is preferably 100,000 to 1500,000, the lower limit is more preferably 150,000, and 200,000 is still more preferable. As for an upper limit, 1200000 is more preferable and 1000000 is still more preferable. If it is less than 100,000, not only is the hysteresis loss large and it is difficult to obtain sufficient fuel efficiency, but the wear resistance also tends to decrease. On the other hand, when it exceeds 1500,000, the workability tends to decrease.

Mw / Mn of the modified conjugated diene polymer is preferably 3 or less, more preferably 2.8 or less. If it exceeds 3, the amount of the low molecular weight component increases, so that the wear resistance tends to deteriorate.
In addition, in this invention, a weight average molecular weight (Mw) and a number average molecular weight (Mn) are measured by the method of the below-mentioned Example.

In the rubber composition of the present invention, the content of the modified conjugated diene polymer is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 50% by mass or more in 100% by mass of the rubber component. If it is less than 30% by mass, the effect of improving fuel economy tends to be difficult to obtain. Although an upper limit is not specifically limited, 90 mass% or less is preferable, 85 mass% or less is more preferable, and 80 mass% or less is still more preferable. If it exceeds 90 mass%, the fracture strength tends to deteriorate.

(Other rubber components)
In the rubber composition of the present invention, a diene rubber can be suitably used as a rubber component that can be used in addition to the modified conjugated diene polymer. The diene rubber is composed of natural rubber (NR) and diene synthetic rubber. Examples of the diene synthetic 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 grip performance and wear resistance are well-balanced, and it is more preferable to use NR and BR in combination. These rubbers may be used alone or in combination of two or more.

When NR and / or BR are included as the rubber component, the total content of NR and BR is preferably 5% by mass or more, more preferably 10% by mass or more, in 100% by mass of the rubber component. If it is less than 5% by mass, the effect of improving the fracture characteristics tends to be difficult to obtain. The total content is preferably 50% by mass or less, more preferably 40% by mass or less. If it exceeds 50% by mass, sufficient wet grip performance may not be obtained.

(silica)
The rubber composition of the present invention is characterized by compounding silica as a reinforcing agent. Here, it is preferable that silica nitrogen adsorption specific surface area _(N 2 SA) is 50 to 300 m ² / g, more preferably more 80~250m ² / g, is 150 to 200 m ² / g It is particularly preferred. Silica with a nitrogen adsorption specific surface area of less than 50 m ² / g has a small reinforcing effect and tends to have low wear resistance, and silica with more than 300 m ² / g has poor dispersibility, increases hysteresis loss, and lowers fuel efficiency. Tend to.

In the rubber composition, the content of silica is 10 to 200 parts by weight, preferably 10 to 150 parts by weight, more preferably 15 to 100 parts by weight, and still more preferably 30 to 70 parts by weight with respect to 100 parts by weight of the rubber component. Part. If the amount is less than 10 parts by mass, the fracture characteristics tend to be insufficient. On the other hand, if the amount exceeds 200 parts by mass, the workability tends to deteriorate. Silica may be used alone or in combination of two or more.

(Silane coupling agent)
The rubber composition of the present invention is also characterized in that the content of the silane coupling agent is 3 parts by mass or less with respect to 100 parts by mass of silica. When a large amount of silane coupling agent is used together with silica, there is a problem that the fracture characteristics are lowered, but in the present invention, the modified conjugated diene polymer is used, and it is not necessary to use the coupling agent. The occurrence of such a problem can be prevented. The content is preferably 2 parts by mass or less, more preferably 1 part by mass or less, still more preferably 0.5 parts by mass or less, and may be 0 parts by mass. If it exceeds 3 parts by mass, the fracture characteristics may be deteriorated.

As the silane coupling agent, any silane coupling agent conventionally used in combination with silica can be used in the rubber industry. For example, sulfide type, mercapto type vinyl type, amino type, glycidoxy type, nitro type And chloro-based silane coupling agents. Specifically, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, bis (3-trimethoxysilylpropyl) Tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (4-trimethoxysilylbutyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) trisulfide Bis (4-triethoxysilylbutyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (2-trimethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis (3-to Ethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) disulfide, Bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilyl Ethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide Sulfides such as 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltri Mercapto series such as ethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane; Vinyl series such as vinyltriethoxysilane, vinyltrimethoxysilane; 3-aminopropyltriethoxysilane, 3-aminopropyltri Amino series such as methoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane; Glycidoxy systems such as sidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane; 3-nitropropyltrimethoxysilane, Nitro-based compounds such as 3-nitropropyltriethoxysilane; chloro-based compounds such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane It is done.

(Other ingredients)
The rubber composition of the present invention includes other reinforcing agents (carbon black and the like), vulcanizing agents, vulcanization accelerators, various oils, anti-aging agents, softeners, plasticizers, zinc oxide, stearic acid and the like for tires. Or various compounding agents and additives mix | blended for general rubber compositions can be mix | blended. Moreover, the content of these compounding agents and additives can also be set to general amounts.

As a method for producing the rubber composition of the present invention, known methods can be used. For example, the above components are kneaded using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanized (crosslinked). It can be manufactured by a method or the like.

<Pneumatic tire>
The pneumatic tire of the present invention can be produced by a usual method using the rubber composition. That is, if necessary, the rubber composition containing the various chemicals is extruded in accordance with the shape of each member (tread, etc.) of the tire at an unvulcanized stage, and is processed on a tire molding machine by a normal method. Mold to form an unvulcanized tire. This unvulcanized tire is heated and pressurized in a vulcanizer to obtain a tire.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.
Below, the various chemical | medical agents used at the time of the synthesis | combination of copolymers (1)-(5) are demonstrated.
n-hexane: Kanto Chemical Co., Ltd. styrene: Kanto Chemical Co., Ltd. 1,3-butadiene: Tokyo Chemical Industry Co., Ltd. p-methoxystyrene: Kanto Chemical Co., Ltd. p-dimethylaminostyrene: Kanto Chemical P- (t-Butoxy) styrene manufactured by: Wako Pure Chemical Industries, Ltd. Tetramethylethylenediamine: n-butyllithium manufactured by Kanto Chemical Co., Ltd .: 1.6M n-butyllithium manufactured by Kanto Chemical Co., Ltd. Hexane solution modifier (1): 1,3-dimethyl-2-imidazolidinone modifier manufactured by Tokyo Chemical Industry Co., Ltd. (2): 3-glycidoxypropyltrimethoxysilane 2,6-produced by Amax Co. tert-Butyl-p-cresol: Nocrack 200 manufactured by Ouchi Shinsei Chemical Co., Ltd.

The obtained copolymer was analyzed by the following method.
<Measurement and identification method>
(Measurement of weight average molecular weight Mw, number average molecular weight Mn)
For Mw and Mn, a GPC-8000 series apparatus manufactured by Tosoh Corporation was used, a differential refractometer was used as a detector, and the molecular weight was calibrated with standard polystyrene.

(Structural identification of copolymer)
The structure identification of the copolymer (measurement of the amount of monomer having a hetero atom-containing functional group in the polymer and the amount of styrene) was measured using an apparatus of JNM-ECA series manufactured by JEOL Ltd.

<Synthesis of copolymer>
(Copolymer (1))
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, 1 g of 2,6-tert-butyl-p-cresol was added to the reaction solution, and then copolymer (1) was obtained by reprecipitation purification. The obtained copolymer had a weight average molecular weight of 470,000, Mw / Mn 1.1, and a styrene component content of 19% by mass.

(Copolymer (2))
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, 0.15 mmol of the modifier (1) was added and stirred for 2 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 (2) was obtained by reprecipitation purification. The obtained copolymer had a weight average molecular weight of 490,000, Mw / Mn 1.1, and a styrene component content of 19% by mass.

(Copolymer (3))
Add 1500 ml of n-hexane, 100 mmol of styrene, 800 mmol of 1,3-butadiene, 5 mmol of p-methoxystyrene, 0.2 mmol of tetramethylethylenediamine, and 0.12 mmol of n-butyllithium to a heat-resistant container sufficiently purged with nitrogen at 0 ° C. Stir for 48 hours. Thereafter, 0.15 mmol of the modifier (1) was added and stirred for 2 hours. Thereafter, alcohol was added to stop the reaction, and 1 g of 2,6-tert-butyl-p-cresol was added to the reaction solution, followed by reprecipitation purification to obtain a copolymer (3). The obtained copolymer had a weight average molecular weight of 500,000, Mw / Mn1.2, a p-methoxystyrene component content of 1.4% by mass, and a styrene component content of 19% by mass.

(Copolymer (4))
To a heat-resistant container sufficiently substituted with nitrogen, 1500 ml of n-hexane, 100 mmol of styrene, 800 mmol of 1,3-butadiene, 5 mmol of p-dimethylaminostyrene, 0.2 mmol of tetramethylethylenediamine, and 0.12 mmol of n-butyllithium were added, For 48 hours. Thereafter, 0.15 mmol of the modifier (1) was added and stirred for 2 hours. Thereafter, alcohol was added to stop the reaction, and 1 g of 2,6-tert-butyl-p-cresol was added to the reaction solution, followed by reprecipitation purification to obtain a copolymer (4). The obtained copolymer had a weight average molecular weight of 520,000, Mw / Mn of 1.2, p-dimethylaminostyrene component content of 1.2% by mass, and styrene component content of 19% by mass.

(Copolymer (5))
Add 1500 ml of n-hexane, 100 mmol of styrene, 800 mmol of 1,3-butadiene, 5 mmol of p- (t-butoxy) styrene, 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, 0.15 mmol of the modifier (2) was added and stirred for 2 hours. Thereafter, alcohol was added to stop the reaction, and 1 g of 2,6-tert-butyl-p-cresol was added to the reaction solution, followed by reprecipitation purification to obtain a copolymer (5). The obtained copolymer had a weight average molecular weight of 490,000, Mw / Mn 1.1, p- (t-butoxy) styrene component content of 1.2% by mass, and styrene component content of 19% by mass.

The various chemicals used in the examples are described below.
NR: RSS # 3
BR: Ubepol BR150B manufactured by Ube Industries, Ltd.
Copolymer: produced as above Silica: Ultrasil VN3 manufactured by Degussa (nitrogen adsorption specific surface area (N ₂ SA): 175 m ² / g)
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 (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Kogyo Co., Ltd.
Vulcanization accelerator (2): Noxeller D (N, N'-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

<Examples 1 to 6, Comparative Example 1>
Each unvulcanized rubber composition was obtained by kneading and blending according to the formulation shown in Table 1. These blends were press vulcanized at 170 ° C. for 15 minutes to obtain vulcanized rubber compositions.
Further, each unvulcanized rubber composition is formed into a tread shape and bonded together with other tire members to form an unvulcanized tire, and press vulcanized at 170 ° C. for 10 minutes, and a test tire (Size 195 / 65R15) was produced.
The following tests were conducted using the obtained vulcanized rubber compositions and test tires.

<Evaluation items and test methods>
(Low fuel consumption)
The 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. The reciprocal value of tan δ was expressed as an index with Comparative Example 1 being 100. The larger the value, the lower the rolling resistance and the lower the fuel consumption.

(Destructive properties (1))
About the said vulcanized rubber composition, the abrasion loss was measured on the conditions of room temperature, a load load of 1.0 kgf, and a slip rate of 30% using the Lambone type abrasion tester. The reciprocal of the amount of wear was displayed as an index with Comparative Example 1 as 100. The larger the value, the better the fracture characteristics.

(Destructive properties (2))
On a test course on an asphalt road surface, a test tire was mounted on a domestic FR vehicle with a displacement of 1800 cc and traveled 20 laps. After traveling, the depth of the groove of the tire was measured, and Comparative Example 1 was set as 100. Larger values indicate better fracture characteristics.

(Wet grip performance (1))
With respect to the vulcanized rubber composition, loss tangent (tan δ) of each blend was measured using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.) at a temperature of 0 ° C., an initial strain of 10% and a dynamic strain of 5% Was measured, and the tan δ of Comparative Example 1 was taken as 100 and indicated as an index. The larger the index, the better the wet grip performance.

(Wet grip performance (2))
On a test course with water and wet road surface, the test tire is mounted on a domestic FR car with a displacement of 1800cc, braked at a speed of 70km / h, and the distance traveled from braking the tire to stopping ( Braking distance). The reciprocal value of the braking distance was displayed as an index with Comparative Example 1 being 100. The larger the index, the higher the wet grip performance.

In the examples using the copolymers (3) to (5) whose main chain and terminal are modified, while being able to achieve both low fuel consumption and fracture characteristics, good wet grip performance is also obtained, and all performances are balanced. Well improved. Particularly in Examples 1 to 4 in which 70 parts by mass of the polymer was used, the performance was further improved. On the other hand, in Comparative Example 1 using the copolymer (2) modified only at the terminal, the performance was poor overall.

Claims (8)

A rubber component comprising a modified conjugated diene polymer having a hetero atom-containing functional group at the main chain and at least one terminal, and silica.
The silica content is 10 to 200 parts by mass with respect to 100 parts by mass of the rubber component,
A tire rubber composition in which the content of the silane coupling agent is 3 parts by mass or less with respect to 100 parts by mass of silica. The modified conjugated diene polymer is obtained by reacting a compound having a monomer unit having a heteroatom-containing functional group in the main chain and having a heteroatom-containing functional group at least at one end. The rubber composition for tires according to 1. The tire rubber composition according to claim 1 or 2, wherein the monomer unit having a hetero atom-containing functional group is a unit derived from a monomer represented by the following formula (I).

(In the formula, X represents a heteroatom-containing functional group.) The tire rubber composition according to any one of claims 1 to 3, wherein the heteroatom-containing functional group is an alkyl-substituted amino group, a cyclic amino group, an alkoxy group, or an alkoxysilyl group. The tire rubber composition according to any one of claims 1 to 4, wherein the content of the modified conjugated diene polymer is 30% by mass or more in 100% by mass of the rubber component. The rubber composition for a tire according to any one of claims 1 to 5, wherein the rubber component further contains natural rubber and / or butadiene rubber. The rubber composition for tires according to any one of claims 1 to 6, which is used for a tread. The pneumatic tire produced using the rubber composition in any one of Claims 1-7.