JP2008163125A - Rubber composition and pneumatic tire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition having excellent wear resistance, low heat build-up and a high-degree balance of gripping performance while suppressing the reduction of processability by the prevulcanization or the like of a composition compounded with an inorganic filler, and to provide a pneumatic tire using the rubber composition at the grounding part of a tread part and having improved properties. <P>SOLUTION: The rubber composition comprises (B) 5-60 pts.mass of an aromatic vinyl compound-diene compound copolymer having 2,000-200,000 weight average molecular weight (polystyrene-equivalent molecular weight by gel-permeation chromatography), and (C) 5-90 pts.mass of an inorganic filler based on (A) 100 pts.mass of a rubber component comprising a natural rubber and/or a synthetic diene rubber, and further comprises (D)1-20 mass% of an organosilicon compound represented by general formula (I): (R<SP>1</SP>O)<SB>3-p</SB>(R<SP>2</SP>)<SB>p</SB>Si-R<SP>3</SP>-Y (I) based on the compounded amount of the inorganic filler. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rubber composition containing an aromatic vinyl compound-diene compound copolymer. More specifically, the present invention maintains the processability of an unvulcanized rubber composition and has excellent wear resistance and low heat build-up. In addition, the present invention relates to a rubber composition having a highly balanced grip property, and a pneumatic tire with improved performance described above, wherein the rubber composition is used for a ground contact portion of a tread portion.

In recent years, demands for lower fuel consumption and safety of automobiles are intensifying in connection with the movement of global carbon dioxide emission regulations accompanying the growing interest in environmental problems. In order to meet such demands, the tire performance is also required to be reduced in rolling resistance and improved in grip performance such as wet performance and dry performance.
Here, as a method for reducing the rolling resistance of the tire, it is effective to use a low heat-generating rubber composition having a lower loss tangent (tan δ) as a rubber composition applied to the tread portion of the tire.
As a method for obtaining a rubber composition having low heat build-up, it is conceivable to reduce the amount of filler such as carbon black or use carbon black having a large particle diameter. Inevitably and a decrease in grip performance on wet road surfaces are inevitable.

In addition, various rubber compositions for tire treads that have both low heat buildup and wet grip properties by blending inorganic fillers such as silica with rubber components such as natural rubber and / or synthetic rubber have been proposed. Has been.
When an inorganic filler such as silica is used, the bond between the inorganic filler and the rubber component becomes weaker than the bond between the carbon black and the rubber component, compared with the case where the conventional carbon black is used. It is necessary to improve the reinforcing property.
Therefore, a rubber composition containing an inorganic filler such as silica reinforces the bond between the inorganic filler and the rubber component and improves the low heat build-up, so that a silane coupling agent that is an organic silane compound is usually used. (For example, see Patent Documents 1 to 3).
Among these silane coupling agents, mercaptosilanes such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and the like are known (for example, Patent Document 4 and Patent Document 4). 5).
However, when kneading these mercaptosilanes into a rubber composition, it causes premature vulcanization known as scorch during processing of the unvulcanized rubber composition, resulting in a significant increase in viscosity and the problem of generation of charred rubber. there were.

On the other hand, as a rubber composition to be applied to the tread portion of a tire, a rubber composition having a high storage elastic modulus (G ′) is suitable for securing a grip, so that the loss tangent (tan δ) is low and the storage elasticity A rubber composition having a high rate (G ′) is demanded. On the other hand, as a means for improving the storage elastic modulus (G ′) of the rubber composition, there is a method of increasing the amount of carbon black compounded in the rubber composition. When the amount is increased, the storage elastic modulus (G ′) of the rubber composition can be improved, but at the same time, the loss tangent (tan δ) of the rubber composition increases and the low heat build-up of the rubber composition decreases. Furthermore, there is a problem that the Mooney viscosity of the rubber composition increases and the processability decreases. Although there is a method of adding a softening agent to improve workability, wear resistance and rolling resistance are lowered. Accordingly, there is an increasing demand for development of a rubber composition having both the above-mentioned conflicting performances.
By using an aromatic vinyl compound-diene compound copolymer having a weight average molecular weight of 5,000 to 300,000 in place of the softening agent, it is possible to suppress deterioration of workability, wear resistance, rolling resistance and storage modulus ( A technique for improving G ′) is disclosed (see, for example, Patent Document 6). However, the market demand for low rolling resistance is increasing and further improvements are desired.

JP 2002-275111 A JP 2005-500420 A JP 2005-35889 A JP 2006-89698 A JP 2006-97024 A WO2005 / 087858 pamphlet

  Under such circumstances, the present invention suppresses deterioration in workability due to early vulcanization of a composition containing an inorganic filler, and has excellent wear resistance, low heat generation, and a high balance of grip. It is an object of the present invention to provide a rubber composition having improved performance as described above, wherein the rubber composition is used in a ground contact portion of a tread portion.

As a result of intensive studies to solve the above-mentioned problems, the present inventor includes an aromatic compound-diene compound copolymer having a specific weight average molecular weight and an inorganic filler, and the inorganic filler. It has been found that the above object can be achieved by adding a specific amount of an organosilicon compound having a specific structure to the material. The present invention has been completed based on such findings.
The present invention has been completed based on such findings.
That is, the present invention is (1) an aromatic vinyl having a rubber component (A) composed of natural rubber and / or synthetic diene rubber and a weight average molecular weight of 2,000 to 200,000 (in terms of polystyrene by gel permeation chromatography). In addition to the compound-diene compound copolymer (B), the rubber component (A) is further included in an amount of 5 to 90 parts by mass of the inorganic filler (C) with respect to 100 parts by mass of the inorganic filler (C). The following general formula (I)
(R ¹ O) _3-p (R ² ) _p Si—R ³ —Y (I)
[Wherein, R ¹ represents a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group, or a linear or branched alkyl group having 2 to 30 carbon atoms. A monoether group or an alkyl polyether group, wherein R ² is a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, or a straight chain having 2 to 30 carbon atoms. A chain or branched alkyl monoether group or alkyl polyether group, —OR ⁴ group or —O—SiR ⁵ ₃ group (wherein the R ⁴ group is linear or branched having 1 to 20 carbon atoms) An alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, a linear or branched alkyl monoether group or alkyl having 2 to 30 carbon atoms A Rieteru group, R ⁵ is alkyl monoether group or a straight-chain or branched having 2 to 30 carbon atoms is an alkyl polyether group), R ³ is an alkylene group having 1 to 20 carbon atoms, a cycloalkylene group, A cycloalkylalkylene group, an alkenylene group, an arylene group or an aralkylene group (wherein R ³ is a substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide bond, sulfonamide bond, ureido bond) , May contain one or more bonds selected from the group consisting of thioureido bond, sulfide bond, carbamate bond, carbonate bond, urea bond and thiourea bond), Y is 1,3-dipole Is a group obtained by removing one hydrogen atom from p, and p represents 0, 1 or 2. A rubber composition comprising 1 to 20% by mass of an organosilicon compound (D) represented by the formula:
(2) The rubber composition according to the above (1), wherein 50% by mass or more of the rubber component (A) comprises a styrene-butadiene copolymer rubber (E),
(3) The component (E) has a weight average molecular weight of 300,000 to 1,500,000 (polystyrene conversion by gel permeation chromatography), styrene is 20 to 60% by mass, and the vinyl bond amount of the butadiene portion. The rubber composition according to the above (2), wherein is 10 to 80% by mass,
(4) A solution in which the component (E) is an emulsion-polymerized styrene-butadiene copolymer comprising 20% by mass or more of styrene and 20% by mass or more of styrene, and the vinyl bond amount of the butadiene portion is 10% by mass or more. The rubber composition according to the above (2) or (3), which is at least one polymerized styrene-butadiene copolymer;
(5) The rubber composition according to any one of (1) to (4), wherein the component (B) contains 5 to 60 parts by mass with respect to 100 parts by mass of the rubber component (A).
(6) The rubber composition as defined in any one of (1) to (5) above, wherein the aromatic vinyl compound as the component (B) is styrene.
(7) The rubber composition according to any one of (1) to (6) above, wherein the diene compound of the component (B) is butadiene.
(8) The rubber composition according to any one of (1) to (7), wherein the component (B) is a solution-polymerized styrene-butadiene copolymer rubber,
(9) Said (1) whose content of the aromatic vinyl compound of said (B) component is 10-80 mass%, and the vinyl bond amount of the diene compound part of this copolymer is 10-80 mass%. To (8) any rubber composition,
(10) The rubber composition according to any one of the above (1) to (9), wherein the difference in the content of the aromatic vinyl compound between the component (E) and the component (B) is 30% by mass or less.
(11) The rubber composition according to any one of (1) to (10) above, wherein the inorganic filler of the component (C) is silica.
(12) Furthermore, (F) Methyltrimethoxysilane, methyltriethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isobutyltrimethoxy with respect to (C) inorganic filler Silane, isobutyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri Acetoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane Lan, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3 -Glycidoxypropyl) triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-isocyanatopropyltri Methoxysilane, 3-isocyanatopropyltriethoxysilane, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) tetrasulfide and octanethioic acid 3 Composed of-(triethoxysilyl) propyl (1) to (11) or a rubber composition in which one or more selected organosilicon compound containing 1 to 20 mass% from
(13) The rubber composition according to any one of (1) to (12), wherein —R ³ — in the general formula (I) representing the organosilicon compound (D) is represented by the following general formula (II):
—R ⁶ —X—R ⁷ — (II)
[Wherein R ⁶ and R ⁷ are each an alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, a cycloalkylalkylene group, an alkenylene group, an arylene group or an aralkylene group (wherein R ⁶ and R ⁷ are X may be a substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide, which may have one or more atoms selected from the group consisting of sulfur atom, nitrogen atom and oxygen atom) It is a bond selected from the group consisting of a bond, a sulfonamide bond, a ureido bond, a thioureido bond, a sulfide bond, a carbamate bond and a carbonate bond. ]
(14) The rubber composition according to any one of (1) to (13) above, wherein the total amount of the component (B) and the softening agent comprises 5 to 80 parts by mass with respect to 100 parts by mass of the rubber component (A).
(15) The rubber composition according to (14), wherein the total amount of the component (B) and the softening agent comprises 5 to 60 parts by mass with respect to 100 parts by mass of the rubber component (A), and (16) 1)-(15) A pneumatic tire characterized by using any rubber composition in at least a ground contact portion of a tread portion,
Is to provide.

  According to the present invention, a rubber composition that suppresses deterioration of workability due to early vulcanization and the like, is excellent in wear resistance, has low heat buildup, and has a high balance of grip properties, and the rubber composition is a tread portion. It is possible to provide a pneumatic tire with improved performance described above, which is used for the ground contact portion.

First, the rubber composition of the present invention has a rubber component (A) composed of natural rubber and / or synthetic diene rubber and an aromatic having a weight average molecular weight of 2,000 to 200,000 (polystyrene conversion by gel permeation chromatography). And an inorganic filler (C) in an amount of 5 to 90 parts by mass with respect to 100 parts by mass of the rubber component (A). ) With respect to the blending amount of the following general formula (I)

(R ¹ O) _3-p (R ² ) _p Si—R ³ —Y (I)
[Wherein, R ¹ represents a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group, or a linear or branched alkyl group having 2 to 30 carbon atoms. A monoether group or an alkyl polyether group, wherein R ² is a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, or a straight chain having 2 to 30 carbon atoms. A chain or branched alkyl monoether group or alkyl polyether group, —OR ⁴ group or —O—SiR ⁵ ₃ group (wherein the R ⁴ group is linear or branched having 1 to 20 carbon atoms) An alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, a linear or branched alkyl monoether group or alkyl having 2 to 30 carbon atoms A Rieteru group, R ⁵ is alkyl monoether group or a straight-chain or branched having 2 to 30 carbon atoms is an alkyl polyether group), R ³ is an alkylene group having 1 to 20 carbon atoms, a cycloalkylene group, A cycloalkylalkylene group, an alkenylene group, an arylene group or an aralkylene group (wherein R ³ is a substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide bond, sulfonamide bond, ureido bond) , May contain one or more bonds selected from the group consisting of thioureido bond, sulfide bond, carbamate bond, carbonate bond, urea bond and thiourea bond), Y is 1,3-dipole Is a group obtained by removing one hydrogen atom from p, and p represents 0, 1 or 2. It is necessary to contain the organic silicon compound (D) represented by 1-20 mass%. If the amount of component (D) is too small, the processability and vulcanized physical properties will be inferior. If it is too large, the elastic modulus of the vulcanized rubber composition will increase.

The component (A) is composed of natural rubber and / or synthetic diene rubber, and the natural rubber is not particularly limited, and any generally available natural rubber can be used.
The synthetic diene rubber is not particularly limited and various rubbers can be applied, but those by emulsion polymerization or solution polymerization are preferable. Further, those having wear resistance and heat resistance and a glass transition temperature of −60 ° C. or higher are preferred.
Specific examples of the synthetic diene rubber include cis-1,4-polyisoprene, styrene butadiene copolymer, low cis-1,4-polybutadiene, high cis-1,4-polybutadiene, and ethylene-propylene-diene copolymer. Examples thereof include coalescence, chloroprene, halogenated butyl rubber, acrylonitrile-butadiene rubber and the like, and natural rubber and synthetic diene rubber can be used alone or in a blend.
Preferred components (A) are natural rubber, cis-1,4-polyisoprene rubber, styrene butadiene copolymer rubber [hereinafter sometimes abbreviated as component (E)], and polybutadiene rubber.

In the component (A), when the styrene butadiene copolymer rubber (E) is contained in an amount of 50% by mass or more, the effect of improving the aromatic vinyl compound-diene compound copolymer (B) described later is preferable. .
The component (E) has a weight average molecular weight of 300,000 to 1,500,000 (polystyrene conversion by gel permeation chromatography), and is preferably contained in the component (A) by 50% by mass or more. . Moreover, (E) component consists of 20-60 mass% styrene, and it is preferable that the vinyl bond amount of a butadiene part is the range of 10-80 mass%. The component (E) ensures excellent compatibility with the component (B) described later, improves the breaking strength (Tb) and the storage elastic modulus (G ′), and stably obtains a low loss tangent (tan δ). be able to.
Solution-polymerized styrene-butadiene, wherein the component (E) is an emulsion-polymerized styrene-butadiene copolymer comprising 20% by mass or more of styrene and 20% by mass or more of styrene, and the vinyl bond content of the butadiene portion is 10% by mass or more. It is preferably at least one copolymer.

Moreover, the rubber composition of this invention contains the aromatic vinyl compound-diene compound copolymer which has a weight average molecular weight (polystyrene conversion by gel permeation chromatography) of 2,000-200,000 as (B) component. It is necessary.
By making the weight average molecular weight of the component (B) within the above range, a rubber composition that maintains wet grip properties without impairing workability, and is highly compatible with storage modulus at low temperatures and low rolling resistance. You can get things. Further, in addition to the above-mentioned various performances, a range of 20,000 to 150,000 is preferable, and a range of 50,000 to 100,000 is more preferable from the viewpoint of improving grip properties in a wide temperature range from low temperature to high temperature. is there.

By applying a low molecular weight aromatic vinyl compound-diene compound copolymer having a weight average molecular weight of less than 2,000 to 200,000 as component (B), both low rolling properties, wear resistance and grip performance are achieved. Although improved, especially when the component (B) having a weight average molecular weight of 2,000 to 50,000, preferably 2,000 to 30,000 is applied, the flexibility and wet performance at a low temperature are maintained at a high level. When the component (B) having a weight average molecular weight of 20,000 to less than 200,000, preferably 50,000 to 150,000 is applied, the storage elastic modulus and low rolling resistance at high temperatures are improved. .
Therefore, in the case where importance is placed on any of wet performance, dry performance and intermediate performance as tire performance, the range of the weight average molecular weight of the component (B) can be selected according to the performance emphasized.
The molecular weight distribution of the component (B) is preferably narrow in order to obtain an excellent low loss tangent (Tanδ).

Furthermore, it is preferable that the rubber composition of this invention contains 5-60 mass parts of said (B) component with respect to 100 mass parts of said (A) component. More preferably, it is 10-50 mass parts. By substituting a part or the total amount of the softening agent with the component (B) and making the content of the component (B) within the above range, the wet performance is maintained and the low rolling resistance and the dry performance are maintained without impairing the workability. Can be improved.
Moreover, the content of the aromatic vinyl compound in the low molecular weight aromatic vinyl compound-diene compound copolymer of the component (B) is 10 to 80% by mass, more preferably 15 to 70% by mass. The vinyl bond content of the diene compound portion is 10 to 80% by mass, more preferably 20 to 70% by mass.
(B) By making the aromatic vinyl compound content and vinyl bond content in the component within the above ranges, desired workability is ensured, and both storage elastic modulus (G ′) and loss tangent (Tanδ) are improved. It becomes possible.
The amount of vinyl bonds specified here indicates the amount of vinyl bonds in the structural unit derived from the diene compound, and the amount of vinyl bonds in the amount of all bonds including other bonds represented by cis bonds and trans bonds. Indicates the percentage.
Furthermore, it is preferable that the difference of the aromatic vinyl compound of the said (E) component and (B) component is 30 mass% or less. By setting the difference between the two aromatic vinyl compounds within the above range, compatibility is ensured and an improvement in the breaking strength (Tb) is recognized.

The low molecular weight aromatic vinyl compound-diene compound copolymer (B) is particularly preferably a styrene-butadiene copolymer.
Here, examples of the monomer of the diene compound include 1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, and among them, 1,3-butadiene is preferable. Examples of the aromatic vinyl compound monomer used for copolymerization with the diene compound monomer include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexyl styrene, 2,2,6-tolyl styrene and the like can be mentioned, among which styrene is preferable.

The low molecular weight aromatic vinyl compound-diene compound copolymer of the component (B) can be produced by a solution polymerization method, and the polymerization method may be either a batch polymerization method or a continuous polymerization method. A preferable production method is as follows.
That is, it is obtained by polymerizing a monomer containing a conjugated diene in an inert solvent, preferably a hydrocarbon solvent, in the presence of an initiator such as an organic metal, preferably an organic lithium compound initiator. Although there is no restriction | limiting in particular as said hydrocarbon solvent, For example, n-pentane, n-hexane, n-heptane, a cyclohexane, benzene, toluene etc. are raised, A preferable solvent is a cyclohexane and n-hexane. These hydrocarbon solvents may be used alone or in combination of two or more.
The organic lithium used as the initiator is preferably a hydrocarbon lithium compound having at least one lithium atom bonded thereto and having 2 to 20 carbon atoms, such as n-butyl lithium, ethyl lithium, n-propyl lithium, tert. -Octyllithium, phenyllithium, etc., with n-butyllithium being preferred. These organolithium initiators may be used alone or in combination of two or more.

The rubber composition of the present invention contains 10 to 90 parts by mass of the inorganic filler (C) with respect to 100 parts by mass of the component (A). Formula (I)
(R ¹ O) _3-p (R ² ) _p Si—R ³ —Y (I)
It is necessary to contain 1-30 mass% of organosilicon compounds (D) represented by these.
In the formula, R ¹ , R ² , p, R ³ and Y are as described above. ]
Silica is preferable as the inorganic filler (C) used in the rubber composition of the present invention. As silica, wet silica obtained by a precipitation method is particularly preferably used. BET specific surface area of silica is preferably 40 to 400 ² / g, more preferably may be between 70~400m ² / g. Examples of such silica include “Nip Seal AQ” manufactured by Tosoh Silica Co., Ltd .; “Ultrasil VN3” manufactured by Degussa; “Zeosil 1165MP”, “Zeosil 165GR” and “Zeosil 175P” manufactured by Rhodia; and “Hisil” manufactured by PPG. 233 "," Hisil 210 "," Hisil 255 ", etc., but are not limited thereto.

Examples of inorganic fillers (C) other than silica used in the rubber composition of the present invention include aluminas containing alumina hydrate (Al ₂ O ₃ .H ₂ O), aluminum hydroxides such as gibbsite and bayerite. [Al (OH) ₃ ], aluminum carbonate [Al ₂ (CO ₃ ) ₂ ], magnesium hydroxide [Mg (OH) ₂ ], magnesium oxide (MgO), magnesium carbonate (MgCO ₃ ), talc (3MgO · 4SiO ₂・ H ₂ O), attapulgite (5MgO.8SiO ₂ .9H ₂ O), titanium white (TiO ₂ ), titanium black (TiO _2n-1 ), calcium oxide (CaO), calcium hydroxide [Ca (OH) ₂ ] , magnesium aluminum oxide _{(MgO · Al 2 O 3)} , clay _{(Al 2 O 3 · 2SiO 2} ), kaolin _{(Al 2 O 3 · 2SiO 2} · 2H 2 O), Pairofi Ito _{(Al 2 O 3 · 4SiO 2} · H 2 O), bentonite _{(Al 2 O 3 · 4SiO 2} · 2H 2 O), aluminum silicate _{(Al 2 SiO 5, Al 4} · 3SiO 4 · 5H 2 O , etc.) , Magnesium silicate (Mg ₂ SiO ₄ , MgSiO ₃ etc.), calcium silicate (Ca ₂ · SiO ₄ etc.), aluminum calcium silicate (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), magnesium calcium silicate (CaMgSiO ₄ ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO (OH) ₂ .nH ₂ O], zirconium carbonate [Zr (CO ₃ ) ₂ ], various zeolites, feldspar, mica and Examples thereof include montmorillonite.
Among these, a case where at least one selected from an oxide or hydroxide of aluminum represented by the following general formula (III) and a hydrate thereof is preferable.
Al ₂ O ₃ · sH ₂ O (III)
[Wherein, s is an integer of 0 to 3. ]
As aluminum hydroxide, the trade name "Hijilite" manufactured by Showa Denko KK is preferable. In the present invention, alumina having aluminum hydroxide on the surface or the like is also regarded as a kind of aluminum hydroxide.
The inorganic fillers exemplified above may be used alone or in combination of two or more. Inorganic fillers other than silica are preferably used in combination with silica.

The compounding amount of the inorganic filler of component (C) used in the rubber composition of the present invention must be 10 to 90 parts by mass with respect to 100 parts by mass of the rubber component (A). Preferably it is 10-80 mass parts. Within this range, the effects of the present invention, that is, sufficient low exothermic property and unvulcanized workability (Mooney viscosity and Mooney scorch time) can be exhibited. In addition, when there are too few compounding quantities of an inorganic filler, reinforcement will become scarce and the tensile stress at the time of 300% expansion | extension of a vulcanized rubber composition will fall. Moreover, when there are too many compounding quantities of an inorganic filler, there exists a tendency for low exothermic property and workability | operativity to fall.
Moreover, the compounding quantity of the organosilicon compound of (D) component used for the rubber composition of this invention needs to be 1-20 mass% with respect to the said inorganic filler, Preferably it is 5-15. It is good that it is mass%.

In the rubber composition of the present invention, the inorganic filler of the component (C) and carbon black may be used in combination. As carbon black, those of FEF, SRF, HAF, ISAF and SAF grade are preferable, and those of HAF, ISAF and SAF grade are more preferable.
The blending amount of the (C) component inorganic filler and carbon black as a filler is preferably 10 to 120 parts by mass with respect to 100 parts by mass of the rubber component. The mixing ratio of black is preferably 1: 0 to 10: 1 by mass ratio. By using carbon black in combination with an inorganic filler, the fracture characteristics and wear resistance of the vulcanized rubber can be improved.

In general, the silane coupling agent has a part capable of binding to a polymer such as rubber and a part capable of binding to an inorganic filler such as silica. For example, the above-described mercaptosilane has a mercapto group as a moiety capable of binding to a polymer.
The organosilicon compound of component (D) used in the rubber composition of the present invention binds a group obtained by removing one hydrogen atom from a 1,3-dipole as a portion capable of binding to a polymer and an inorganic filler such as silica. By having (R ¹ O) _3-p (R ² ) _p Si— group (where R ¹ , R ² and p are as described above) as a possible portion, the above-mentioned effect is exhibited for the first time. It was.

The 1st organosilicon compound which is (D) component used for the rubber composition of this invention is represented by the following general formula (I).
(R ¹ O) _3-p (R ² ) _p Si—R ³ —Y (I)
Here, R ¹ is a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group, or a linear or branched alkyl monovalent group having 2 to 30 carbon atoms. An ether group or an alkyl polyether group, and R ² is a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group, or a linear chain having 2 to 30 carbon atoms. Alternatively, it is a branched alkyl monoether group or alkyl polyether group, —OR ⁴ group or —O—SiR ⁵ ₃ group. Here, the R ⁴ group is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group, or a linear or branched alkyl monoether group or alkyl polyether having 2 to 30 carbon atoms. R ⁵ is a linear or branched alkyl monoether group or alkyl polyether group having 2 to 30 carbon atoms.
R ³ is an alkylene group having 1 to 20 carbon atoms, a cycloalkylene group, a cycloalkylalkylene group, an alkenylene group, an arylene group or an aralkylene group. Here, in R ³ , a substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide bond, sulfonamide bond, ureido bond, thioureido bond, sulfide bond, carbamate bond, carbonate bond, One or more types of bonds selected from the group consisting of urea bonds and thiourea bonds may be included.
Y represents a group obtained by removing one hydrogen atom from a 1,3-dipole, and p represents 0, 1 or 2.

Moreover, it is preferable that -R < ³ >-of the said general formula (I) is the organosilicon compound (D) represented by the following general formula (II).
—R ⁶ —X—R ⁷ — (II)
Here, R ⁶ and R ⁷ are each an alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, a cycloalkylalkylene group, an alkenylene group, an arylene group, or an aralkylene group. R ⁶ and R ⁷ may have one or more atoms selected from the group consisting of a sulfur atom, a nitrogen atom and an oxygen atom.
Furthermore, R ⁶ and R ⁷ are optionally substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide bond, sulfonamide bond, ureido bond, thioureido bond in R ⁶ and R ⁷ , One or more types of bonds selected from the group consisting of sulfide bonds, carbamate ester bonds, carbonate ester bonds, urea bonds, and thiourea bonds may be included.
X is selected from the group consisting of a substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide bond, sulfonamide bond, ureido bond, thioureido bond, sulfide bond, carbamate bond and carbonate bond. This is a bond.

Specific examples of R ¹ and R ² in the above general formula (I) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert- Butyl group, n-pentyl group, isopentyl group, tert-pentyl group, cyclopentyl group, n-hexyl group, isohexyl group, cyclohexyl group, n-heptyl group, isoheptyl group, n-octyl group, 2-ethylhexyl group, isooctyl group Propenyl group, allyl group, various butenyl groups, various pentenyl groups, cyclopentenyl groups, various hexenyl groups, cyclohexenyl groups, various heptenyl groups, various octenyl groups, and the like. Among these, an n-hexyl group, an isohexyl group, a cyclohexyl group, an n-heptyl group, an isoheptyl group, various hexenyl groups, a cyclohexenyl group, and various heptenyl groups are particularly preferable.

In the organosilicon compound (D) in which the above general formulas (I) and -R ³ -are represented by the general formula (II), examples of 1,3-dipoles used for Y include azide, diazoalkane, Compounds selected from the group consisting of nitrite oxide, nitrile imine, azomethine imine, nitrile ylide, azomethine ylide, nitrile oxide, azoxy compound, nitrone and their precursors are preferred.
Preferred examples of these 1,3-dipoles include A1-C (A2) = N (A3) → O (nitrone system), A1-C≡N → O (nitrile oxide system), and A1-C≡N. → N-A4 (nitrile imine type) is exemplified. These 1,3-dipoles are reactively bonded to a double bond portion in a polymer such as a rubber component as shown in the following reaction formulas (1) to (3).

In Scheme (1) to (3) above, B has the general formula in (I) (R ¹ O) _3-p (R ²⁾ represents a _p Si-, P represents a polymer molecular chain, A1 is R ³ and the groups A2 to A4 are preferably hydrogen, a group having 20 or less carbon atoms, or a connecting chain. When the number of carbon atoms exceeds 20, the molecular weight of the compound itself increases, and the reactivity with the rubber component becomes worse.
Specific groups or connecting chains of A2 to A4 are specifically hydrogen, a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, and a carbon number. From 6 to 20 aryl groups and aralkyl groups (however, the aromatic ring may have a nitro group, a cyano group, a chloro group, a bromo group, an acyl group, a carbonylalkyl group, an alkyl group, and an alkoxyl group). A group selected from the group consisting of: The acyl group, carbonylalkyl group, and alkoxyl group may have a branched chain or a cyclo ring. A2 to A4 may be the same or different.

  Specific examples of the organosilicon compound of the present invention represented by the general formula (I) include, for example, N- (3-triethoxysilylpropyl) -4-phenyliminomethylbenzamide-N-oxide, S- (3- Triethoxysilylpropyl) -4-phenyliminomethylthiobenzoate-N-oxide, 3-azidopropyltriethoxysilane, N- (triethoxysilylpropyl) -4-phenyliminomethylaniline-N-oxide, 4- (3- And triethoxysilylpropyl) oxy) phenyliminomethylbenzene-N-oxide and 3-cyanopropyltriethoxysilane-N-oxide.

The organosilicon compound (D) used in the rubber composition of the present invention can be produced by combining various known reaction methods. For example, N- (3-triethoxysilylpropyl) -4-phenyliminomethylbenzamide-N-oxide or S- (3-triethoxysilylpropyl) -4-phenyliminomethylthiobenzoate-N-oxide is N- ( 3-Triethoxynyl) propyl-4-formylbenzamide or S- (3-triethoxysilylpropyl) -4-formylthiobenzoate may be reacted with N-phenylhydroxylamine in an organic solvent such as toluene. .
Further, 3-azidopropyltriethoxysilane may be prepared by reacting (3-chloropropyl) triethoxysilane with sodium azide in an acetone solvent.
Nitrone can be prepared by dehydrating condensation of hydroxylamine and aldehyde, and azide can be obtained by reacting an alkyl halide with an azide ion (for example, the sodium salt of azide).

In the present invention, when an inorganic filler, particularly silica, is blended, it is desirable to further add (F) an organosilicon compound.
(F) Examples of the organosilicon compound include methyltrimethoxysilane, methyltriethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n -Octyltrimethoxysilane, n-octyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, 3-methacryloxypropyl Trimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-a Minoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3-glycidoxypropyl) triethoxy Silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyl From triethoxysilane, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) tetrasulfide and octanethioate 3- (triethoxysilyl) propyl Select one or more from the group Silane compounds are preferred. Among these, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) tetrasulfide, octanethioate 3- (triethoxysilyl) propyl, etc. Is particularly preferred.
Said (F) component may be used individually by 1 type, and may use 2 or more types together. (F) As a compounding quantity of a component, 1-20 mass% is preferable with respect to the compounding quantity of the said inorganic filler (silica), and 5-15 mass% is more preferable.

The rubber composition of the present invention may further contain a softening agent. Here, examples of the softening agent include process oils such as paraffin oil, naphthenic oil, and aroma oil. Aromatic oil is preferable from the viewpoint of fracture characteristics and wear resistance, and from the viewpoint of low heat generation and low temperature characteristics. Are preferably naphthenic oils and paraffin oils.
The blending amount of the softening agent is not particularly limited, but the total blending amount of the low molecular weight aromatic vinyl compound-diene compound copolymer and the softening agent of the component (B) is the component (A) 100. It is preferable to mix | blend so that it may become 5-80 mass parts with respect to a mass part, More preferably, it is 5-60 mass parts. By making the total blending amount of the component (B) and the softening agent within the above range, it is possible to suppress the deterioration of the fracture characteristics of the vulcanized rubber.

  The rubber composition of the present invention includes various additives usually used in the rubber composition in addition to the above-described components, for example, a vulcanizing agent such as sulfur, a vulcanization accelerator, and a vulcanization acceleration aid (zinc oxide, stearic acid). Etc.), anti-aging agents (antioxidants, ozone deterioration inhibitors, etc.) and the like can be appropriately blended.

  The rubber composition of the present invention is obtained by kneading using a kneader such as a Banbury mixer, a roll, an internal mixer, etc., and after molding and vulcanizing, such as pneumatic tires, various industrial rubber products, etc. Used for applications.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. Various measurement methods were performed based on the following methods.
<Measurement of Weight Average Molecular Weight, Microstructure and Styrene Content of Copolymer (B) Component>
(1) Weight average molecular weight (Mw)
Gel permeation chromatography [GPC: Tosoh HLC-8020, column: Tosoh GMH-XL (two in series), detector: differential refractometer (RI)], based on monodisperse polystyrene, The weight average molecular weight (Mw) in terms of polystyrene was determined.
(2) Microstructure and bound styrene content The microstructure of the polymer was determined by the infrared method (Morero method), and the bound styrene content of the polymer was determined from the integral ratio of the ¹ H-NMR spectrum.

<Measurement of G ′ and Tanδ of Vulcanized Rubber>
(3) Storage elastic modulus (G ′) and loss tangent (tan δ)
Using a rheometrics viscoelasticity measuring device, a storage elastic modulus (G ′) and a loss tangent (tan δ) are measured at a temperature of 50 ° C., a frequency of 15 Hz, and a strain of 5%, and a rubber composition using an aromamy oil. The storage elastic modulus (G ′) and loss tangent (tan δ) of the rubber composition of Comparative Example 1 were each expressed as an index with the value of 100. As for the storage elastic modulus (G ′), the larger the index value, the higher the storage elastic modulus, while regarding the loss tangent (tan δ), the smaller the index value, the better the low heat buildup.
<Abrasion resistance test of vulcanized rubber>
(4) In accordance with JIS K 6264-1: 2005, a wear amount with a slip rate of 60% was measured at room temperature using a Lambone-type wear tester. The results were indexed with the reciprocal of the amount of wear in each example, with the value of the reciprocal of the amount of wear obtained in Comparative Example 1 being 100. It shows that abrasion resistance is excellent, so that a numerical value is large.

Production Example 1: Polymerization of Low Molecular Weight Aromatic Vinyl Compound-Diene Compound Copolymer (B-1) as Component (B) Into an 800 mL pressure-resistant glass container dried and purged with nitrogen, 300 g of cyclohexane, 1,3- After adding 40 g of butadiene, 13 g of styrene and 0.90 mmol of ditetrahydrofurylpropane, and further adding 0.90 mmol of n-butyllithium (n-BuLi), a polymerization reaction was carried out at 50 ° C. for 2 hours. The polymerization conversion rate at this time was almost 100%.
After completion of the polymerization reaction, 0.5 mL of an isopropanol solution (BHT concentration: 5% by mass) of 2,6-di-t-butyl-p-cresol (BHT) is added to the polymerization reaction system to stop the polymerization reaction. It dried according to the conventional method and obtained the copolymer (B). The amount of bound styrene was 25% by mass, the amount of vinyl bonds in the butadiene portion was 65%, and the weight average molecular weight was 80,000.

Production Example 2: Synthesis of component (D) organosilicon compound (1) Preparation of S- (3-triethoxysilylpropyl) -4-formylthiobenzoate Sodium hydride (purity 60%) in a 50 ml eggplant type flask 0.53 g (13.1 mmol, 1.1 eq) and 5 ml of THF were added, and a THF solution of 2.37 g (11.9 mmol) of 3-mercaptopropyltriethoxysilane was slowly added dropwise at room temperature with stirring. . After the addition, the reaction solution was refluxed for 20 minutes.
To a 100 ml three-necked flask equipped with a thermometer, a calcium chloride tube, and a dropping funnel, 2.0 g (11.9 mmol) of 4-formylbenzoic acid chloride and 10 ml of THF were added and prepared by the above method. The reaction solution was slowly added dropwise so that the reaction temperature did not exceed 20 ° C., and stirred at room temperature for 15 minutes after the addition. Since the completion of the reaction was confirmed by thin layer chromatography, the insoluble matter was removed by filtration under reduced pressure, and the filtrate was concentrated. The obtained reaction product was used in the next step without purification.
(2) Preparation of S- (3-triethoxysilylpropyl) -4-phenyliminomethylthiobenzoate-N-oxide The above reactants, 10 ml of toluene, and sulfuric acid were added to a 100 ml flask formed with a Dimroth condenser and a calcium chloride tube. An appropriate amount of magnesium was added. Under stirring, 1.3 g of n-phenylhydroxylamine (1.0 equivalent based on 4-formylbenzoic acid chloride) was added in portions and refluxed for 15 minutes after the addition. Since the completion of the reaction was confirmed by thin layer chromatography, the insoluble matter was removed by filtration under reduced pressure, and the filtrate was concentrated. The resulting reaction product was purified by column chromatography {cyclohexane / ethyl acetate = (3 / l) to (0 / l)} using Florisil to obtain 3.29 g of the desired product. (Yield is 60% in 2 steps) From the NMR measurement result, it was confirmed to be the desired product S- (3-triethoxysilylpropyl) -4-phenyliminomethylthiobenzoate-N-oxide. The melting point was 49 ° C.
¹ H-NMR (600 MHz, CDCl ₃ )
8.45 (2H, d, 8Hz), 8.06 (2H, d, 8Hz), 7.99 (1H, s), 7.80-7.78 (2H, m), 7.49-7. 52 (3H, m), 3.83 (6H, q, 7 Hz), 3.14 (2H, t, 7 Hz), 1.82 (2H, tt, 6 Hz, 8 Hz), 1.25 (9H, t, 7Hz), 0.82 (2H, t, 6Hz)

Examples 1-3, Comparative Examples 1-5
A rubber composition having the formulation shown in Table 1 was prepared, and the rubber composition was further vulcanized at 160 ° C. for 15 minutes to obtain a vulcanized rubber. The storage elastic modulus (G ′) of the vulcanized rubber and Loss tangent (tan δ) and wear resistance were measured by the above methods. The results are shown in Table 1.

［注１］
＊１．（Ａ）成分 ＳＢＲ：ＪＳＲ社製「＃１５００」乳化重合ＳＢＲ、重量平均分子量（４５０，０００）、スチレン含量（２３．５質量％）、ブタジエン部のビニル結合量（１８質量％）
＊２．カーボンブラック：東海カーボン社製「シーストＫＨ」（Ｎ３３９）
＊３．（Ｃ）成分 無機充填材シリカ：東ソー・シリカ社製「ニプシールＡＱ」
＊４．（Ｆ）成分 有機珪素化合物（シランカップリング剤）：デグサ社製「Ｓｉ６９」ビス（３−トリエトキシプロピルテトラスルフィド
＊５．（Ｄ）成分有機珪素化合物：製造例２の有機珪素化合物、Ｓ−（３−トリエトキシシリルプロピル）−４−フェニルイミノメチルチオベンゾエート−Ｎ−オキシド
＊６．（Ｂ）成分低分子量共重合体：製造例１の低分子量共重合体（Ｂ−１）
＊７．老化防止剤６Ｃ：大内新興化学工業社製、「ノクラック６Ｃ」Ｎ−（１，３−ジメチルブチル）−Ｎ’−フェニル−ｐ−フェニレンジアミン
＊８．加硫促進剤ＤＰＧ：三新化学工業社製「サンセラーＤ」ジフェニルグアニジン
＊９．加硫促進剤ＤＭ：三新化学工業社製「サンセラーＤＭ」ジベンゾチアジルスルフィド
＊１０．加硫促進剤ＮＳ：三新化学工業社製「サンセラーＮＳ」Ｎ−ｔ−ブチル−２−ベンゾチアジルスルフェンアミド

[Note 1]
* 1. (A) Component SBR: “# 1500” emulsion polymerization SBR manufactured by JSR, weight average molecular weight (450,000), styrene content (23.5 mass%), vinyl bond content of butadiene part (18 mass%)
* 2. Carbon black: “Seast KH” manufactured by Tokai Carbon Co., Ltd. (N339)
* 3. Component (C) Inorganic filler silica: “Nipseal AQ” manufactured by Tosoh Silica
* 4. Component (F) Organosilicon compound (silane coupling agent): “Si69” bis (3-triethoxypropyltetrasulfide * 5. (D) component manufactured by Degussa Co., Ltd. Organosilicon compound: Organosilicon compound of Production Example 2, S— (3-Triethoxysilylpropyl) -4-phenyliminomethylthiobenzoate-N-oxide * 6. (B) Component Low molecular weight copolymer: Low molecular weight copolymer of Production Example 1 (B-1)
* 7. Anti-aging agent 6C: “Nocrack 6C” N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine manufactured by Ouchi Shinsei Chemical Co., Ltd. * 8. Vulcanization accelerator DPG: “Sunceller D” diphenylguanidine manufactured by Sanshin Chemical Industry * 9. Vulcanization accelerator DM: “Sunseller DM” dibenzothiazyl sulfide manufactured by Sanshin Chemical Industry * 10. Vulcanization accelerator NS: “Suncellor NS” manufactured by Sanshin Chemical Industry Co., Ltd. Nt-butyl-2-benzothiazylsulfenamide

As is apparent from Table 1, Examples 1 to 3 of the present invention are all compared to Comparative Examples 1 to 5,
It can be seen that a rubber composition having a high storage elastic modulus (G ′), a low loss tangent (tan δ), low exothermic property and excellent wear resistance has been obtained, and the object of the present invention has been achieved. .
In Examples 1, 2 and 3, no deterioration in workability due to early vulcanization or the like was observed.

  The rubber composition of the present invention is suitably used as a tread of various pneumatic radial tires for passenger cars, light trucks, light passenger cars, light trucks and large vehicles.

Claims (16)

An aromatic vinyl compound-diene compound copolymer having a rubber component (A) composed of natural rubber and / or synthetic diene rubber and a weight average molecular weight of 2,000 to 200,000 (polystyrene conversion by gel permeation chromatography) ( B) and further 5 to 90 parts by mass of the inorganic filler (C) with respect to 100 parts by mass of the rubber component (A), and with respect to the blending amount of the inorganic filler (C), the following Formula (I)
(R ¹ O) _3-p (R ² ) _p Si—R ³ —Y (I)
[Wherein, R ¹ represents a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group, or a linear or branched alkyl group having 2 to 30 carbon atoms. A monoether group or an alkyl polyether group, wherein R ² is a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, or a straight chain having 2 to 30 carbon atoms. A chain or branched alkyl monoether group or alkyl polyether group, —OR ⁴ group or —O—SiR ⁵ ₃ group (wherein the R ⁴ group is linear or branched having 1 to 20 carbon atoms) An alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, a linear or branched alkyl monoether group or alkyl having 2 to 30 carbon atoms A Rieteru group, R ⁵ is alkyl monoether group or a straight-chain or branched having 2 to 30 carbon atoms is an alkyl polyether group), R ³ is an alkylene group having 1 to 20 carbon atoms, a cycloalkylene group, A cycloalkylalkylene group, an alkenylene group, an arylene group or an aralkylene group (wherein R ³ is a substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide bond, sulfonamide bond, ureido bond) , May contain one or more bonds selected from the group consisting of thioureido bond, sulfide bond, carbamate bond, carbonate bond, urea bond and thiourea bond), Y is 1,3-dipole Is a group obtained by removing one hydrogen atom from p, and p represents 0, 1 or 2. ] The rubber composition characterized by including the organic silicon compound (D) represented by 1-20 mass%.   The rubber composition according to claim 1, wherein 50% by mass or more of the rubber component (A) is composed of a styrene-butadiene copolymer rubber (E).   The component (E) has a weight average molecular weight of 300,000 to 1,500,000 (polystyrene conversion by gel permeation chromatography), styrene is 20 to 60% by mass, and the vinyl bond amount of the butadiene portion is 10 to 10. The rubber composition according to claim 2, which is 80% by mass.   Solution-polymerized styrene-butadiene, wherein the component (E) is an emulsion-polymerized styrene-butadiene copolymer comprising 20% by mass or more of styrene and 20% by mass or more of styrene, and the vinyl bond content of the butadiene portion is 10% by mass or more. The rubber composition according to claim 2 or 3, which is at least one of copolymers.   The rubber composition according to any one of claims 1 to 4, comprising 5 to 60 parts by mass of the component (B) with respect to 100 parts by mass of the rubber component (A).   The rubber composition according to any one of claims 1 to 5, wherein the aromatic vinyl compound as the component (B) is styrene.   The rubber composition according to any one of claims 1 to 6, wherein the diene compound as the component (B) is butadiene.   The rubber composition according to any one of claims 1 to 7, wherein the component (B) is a solution polymerized styrene-butadiene copolymer rubber.   The content of the aromatic vinyl compound as the component (B) is 10 to 80% by mass, and the vinyl bond content of the diene compound portion of the copolymer is 10 to 80% by mass. A rubber composition according to any one of the above.   The rubber composition according to any one of claims 1 to 9, wherein a difference in the content of the aromatic vinyl compound between the component (E) and the component (B) is 30% by mass or less.   The rubber composition according to any one of claims 1 to 10, wherein the inorganic filler of the component (C) is silica.   Furthermore, (C) Inorganic filler, (F) methyltrimethoxysilane, methyltriethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, isobutyltrimethoxysilane, isobutyl Triethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methoxyethoxy) silane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, (3-glycidoxypropyl) trimethoxysilane, (3-glycidoxy Propyl) triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3 -Isocyanatopropyltriethoxysilane, bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) tetrasulfide and octanethioic acid 3- (triethoxy 1 from the group consisting of silyl) propyl A rubber composition according to any one of claims 1 to 11 containing an organic silicon compound selected or 1 to 20 mass%. The rubber composition according to claim 1, wherein —R ³ — in the general formula (I) representing the organosilicon compound (D) is represented by the following general formula (II).
—R ⁶ —X—R ⁷ — (II)
[Wherein R ⁶ and R ⁷ are each an alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, a cycloalkylalkylene group, an alkenylene group, an arylene group or an aralkylene group (wherein R ⁶ and R ⁷ are X may be a substituted or unsubstituted ether bond, amino bond, ester bond, thiol ester bond, amide, which may have one or more atoms selected from the group consisting of sulfur atom, nitrogen atom and oxygen atom) It is a bond selected from the group consisting of a bond, a sulfonamide bond, a ureido bond, a thioureido bond, a sulfide bond, a carbamate bond and a carbonate bond. ]   The rubber composition according to any one of claims 1 to 13, wherein the total amount of the component (B) and the softening agent comprises 5 to 80 parts by mass with respect to 100 parts by mass of the rubber component (A).   The rubber composition according to claim 14, wherein the total amount of the component (B) and the softener comprises 5 to 60 parts by mass with respect to 100 parts by mass of the rubber component (A).   A pneumatic tire using the rubber composition according to any one of claims 1 to 15 for at least a ground contact portion of a tread portion.