JP7103574B2 - Rubber composition and tires - Google Patents

Description

The present invention relates to rubber compositions and tires.

In recent years, under the social demand for energy saving and resource saving, tires having low rolling resistance have been demanded in order to save fuel consumption of automobiles. In response to such demands, as a method for reducing the rolling resistance of a tire, a rubber composition in which the hysteresis loss is reduced by reducing the amount of carbon black used, using lower carbon black, etc., that is, heat generating property A method of using a low rubber composition for a tire member, particularly a tread rubber, is known.

For example, in order to obtain a tire for a two-wheeled vehicle capable of achieving both wet grip performance and chunking resistance, a rubber composition for a tread of a two-wheeled vehicle tire contains a rubber component, silica and carbon black, and the rubber component is a natural rubber. The silica has a CTAB specific surface area of 180 m ² / g or more and a BET specific surface area of 185 m ² / g or more, and the carbon black with respect to 100 parts by mass of the rubber component. It is disclosed that the content of the rubber is 15 parts by mass or more (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-174048

However, in the method described in Patent Document 1, although low heat generation and abrasion resistance can be improved to some extent, silica aggregates when silica having a fine particle size having a CTAB of 200 m ² / g or more is used. Since it becomes easy, the vulcanized rubber has deteriorated in low heat generation.
In addition, low rolling resistance can be easily achieved by using carbon black with low reinforcing properties or by reducing the amount of carbon black blended, but this method reduces wear resistance because the strength of the tread is reduced. Has decreased. On the other hand, if carbon black having a fine particle size having high reinforcing properties is used, wear resistance can be improved. By making the particle size fine, the dispersion of carbon black in the rubber component becomes poor, and vulcanization is performed. There is a problem that the heat generation of the rubber composition becomes high.

In view of the above circumstances, the present invention provides a rubber composition capable of obtaining a vulcanized rubber having excellent low heat generation without impairing wear resistance, and a tire having excellent low loss property without impairing wear resistance. That is the issue.

<1> A filler containing carbon black (B) having a specific surface area of 20 to 195 m ² / g and silica (C) having a specific surface area of cetyltrimethylammonium bromide of 200 m ² / g or more.
The isoprene-based rubber (A-1) having at least one isoprene-based rubber (A-1) selected from the group consisting of natural rubber and polyisoprene rubber and a functional group having an affinity for the filler, said isoprene-based rubber (A-1). A rubber component (A) containing a modified conjugated diene polymer (A-2) that is incompatible with
Including
In the rubber component (A), the content of the isoprene rubber (A-1) is 50 to 85% by mass, and the content of the modified conjugated diene polymer (A-2) is 15 to 50% by mass. can be,
The total amount of the carbon black (B) content (b) and the silica (C) content (c) is 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component (A).
A rubber composition in which the ratio of the content (b) to the content (c) is (b) :( c) = 60 to 85: 40 to 15 on a mass basis.

<2> In the rubber component (A), the content of the isoprene rubber (A-1) is 60 to 80% by mass, and the content of the modified conjugated diene polymer (A-2) is 20 to 40. The rubber composition according to <1>, which is by mass%.

<3> The ratio of the carbon black (B) content (b) to the silica (C) content (c) is based on mass, (b): (c) = 70 to 85:30. 15. The rubber composition according to <1> or <2>.

<4> The rubber composition according to any one of <1> to <3>, wherein the silica (C) has a specific surface area of cetyltrimethylammonium bromide of 210 m ² / g or more.

<5> Any one of <1> to <4>, wherein the functional group having an affinity for the filler contains at least one selected from the group consisting of an oxygen atom, a silicon atom, and a nitrogen atom. The rubber composition according to.

<6> Any one of <1> to <5> in which the functional group having an affinity for the filler contains at least one selected from the group consisting of oxygen atoms and silicon atoms and a nitrogen atom. The rubber composition according to.

<7> A tire using the rubber composition according to any one of <1> to <6>.

According to the present invention, it is possible to provide a rubber composition capable of obtaining a vulcanized rubber having excellent low heat generation without impairing wear resistance, and a tire having excellent low loss property without impairing wear resistance. ..

<Rubber composition>
The rubber composition of the present invention contains a rubber component (A) and a filler.
The rubber component (A) is at least one isoprene-based rubber (A-1) selected from the group consisting of natural rubber and polyisoprene rubber, and a modified conjugated diene-based rubber having a functional group having an affinity for a filler. Contains the polymer (A-2). The isoprene-based rubber (A-1) and the modified conjugated diene-based polymer (A-2) are incompatible with each other. The content of the isoprene-based rubber (A-1) in the rubber component (A) is 50 to 85% by mass, and the content of the modified conjugated diene-based polymer (A-2) is 15 to 50% by mass. ..
The filler contains carbon black (B) having a specific surface area of 20 to 195 m ² / g of cetyltrimethylammonium bromide and silica (C) having a specific surface area of 200 m ² / g or more of cetyltrimethylammonium bromide.
The total amount (b + c) of the carbon black (B) content (b) and the silica (C) content (c) is 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component (A). The ratio of the content (b) to the content (c) is (b): (c) = 60 to 85:40 to 15.
Hereinafter, the specific surface area of cetyltrimethylammonium bromide may be referred to as "CTAB specific surface area" or simply "CTAB".

As described above, by including both carbon black and silica in the rubber composition, low heat generation, abrasion resistance and crack resistance can be improved to some extent, but the CTAB is 200 m ² / g or more. When silica having such a fine particle size is used, the silica easily aggregates, so that the vulcanized rubber has deteriorated in low heat generation property.
However, in the present invention, even if silica having a fine particle size having a CTAB of 200 m ² / g or more is used, by adopting the rubber composition as described above, the wear resistance is not impaired and the heat generation is low. It was found that an excellent vulcanized rubber can be obtained. The reason for this is not clear, but it is presumed to be due to the following reasons.

The heat generation of the vulcanized rubber is generally generated by the fillers such as carbon black and silica contained in the vulcanized rubber rubbing against each other in the rubber. Therefore, as described above, it is low in an environment where silica tends to aggregate. The feasibility tends to worsen.
In the present invention, the filler is contained in a rubber matrix containing an isoprene-based rubber (A-1) and a modified conjugated diene-based polymer (A-2), which are incompatible with each other. It is considered that the modified conjugated diene-based polymer (A-2) phase is likely to be unevenly distributed, and local strain of the vulcanized rubber obtained by vulcanizing the rubber composition of the present invention is less likely to occur. As a result, it is considered that the wear resistance of the vulcanized rubber is less likely to be impaired.
Further, due to the low heat generation of the silica compounding system, the vulcanized rubber obtained from the rubber composition of the present invention can improve the low heat generation without impairing the wear resistance, and is excellent in low heat generation. Conceivable.
Hereinafter, details of the rubber composition and the tire of the present invention will be described.

[Rubber component (A)]
The rubber composition of the present invention contains a rubber component (A). The rubber component (A) is filled with at least one isoprene-based rubber (A-1) selected from the group consisting of natural rubber and polyisoprene rubber. It contains at least a modified conjugated diene polymer (A-2) that has a functional group having an affinity for the agent and is incompatible with the isoprene rubber (A-1).
The rubber component (A) is phase-separated between the isoprene rubber (A-1) and the modified conjugated diene polymer (A-2), and the filler is unevenly distributed in the modified conjugated diene polymer (A-2) phase. By doing so, the abrasion resistance of the vulture rubber and the tire is excellent.
The rubber component (A) may further contain an unmodified conjugated diene polymer (A-3), and the non-conjugated diene polymer (A-4) may be contained as long as the effects of the present invention are not impaired. ) May be included. The non-conjugated diene polymer (A-4) may be modified or unmodified.

Here, the fact that the isoprene-based rubber (A-1) and the modified conjugated diene-based polymer (A-2) are incompatible with each other may be incompatible with each other on the submicron order, and is observed with the naked eye. May be compatible with. In order to observe incompatibility on the submicron order, for example, using FIB / SEM, observe a region of 4 μm × 4 μm of the rubber composition, and if there is a difference in dyeing condition, it is considered to be incompatible. There is a way to judge.

The content of the isoprene-based rubber (A-1) in the rubber component (A) is 50 to 85% by mass, and the content of the modified conjugated diene-based polymer (A-2) is 15 to 50% by mass. .. The mass ratio of the isoprene rubber (A-1) and the modified conjugated diene polymer (A-2) may be 50:50, but from the viewpoint of improving the wear resistance of the vulcanized rubber and the tire. The isoprene-based rubber (A-1) preferably exceeds 50% by mass and is in a continuous phase. From the same viewpoint, the content of the isoprene rubber (A-1) in the rubber component (A) is 60 to 80% by mass, and the content of the modified conjugated diene polymer (A-2) is 20 to 40% by mass. More preferably.
When the rubber component (A) further contains an unmodified conjugated diene polymer (A-3), the content in the rubber component (A) may be 20% by mass or less from the viewpoint of low heat generation. It is preferably 10% by mass or less, and more preferably 10% by mass or less. The content of the unmodified conjugated diene polymer (A-3) in the rubber component (A) is more preferably 0% by mass.

As the isoprene-based rubber (A-1), only one of natural rubber and polyisoprene rubber may be used, or both may be used, but at least natural rubber is preferably used, and only natural rubber is used. Is more preferable.
As the polymer before modification of the modified conjugated diene polymer (A-2), that is, the unmodified conjugated diene polymer (A-3), synthetic conjugated diene rubber other than polyisoprene rubber (IR) is used. Specific examples thereof include polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), butadiene-isoprene copolymer rubber (BIR), styrene-isoprene copolymer rubber (SIR), and styrene-butadiene. -Isoprene copolymer rubber (SBIR) and the like can be mentioned.
The synthetic conjugated diene rubber may be used alone or in combination of two or more.
Among the above, polybutadiene rubber (BR) and styrene-butadiene copolymer rubber (SBR) are preferable.

The modified conjugated diene polymer (A-2) has a functional group having an affinity for the filler. Hereinafter, the "functional group having an affinity for the filler" may be referred to as a modified functional group. Since the modified conjugated diene polymer (A-2) has a modified functional group, the filler can be easily unevenly distributed in the modified conjugated diene polymer (A-2) phase.
"Having affinity for the filler" can be rephrased as "having an interaction with the filler", specifically, between the modified functional group and the filler surface. For example, it means forming a covalent bond; an intermolecular force (an intermolecular force such as an ion-dipole interaction, a dipole-dipole interaction, a hydrogen bond, or a van der Waals force).
The modified functional group having high interaction with the filler is not particularly limited, and examples thereof include a nitrogen-containing functional group, a silicon-containing functional group, and an oxygen-containing functional group.

Oxygen atoms and silicon atoms tend to have high affinity (interactivity) with silica, and nitrogen atoms tend to have high affinity (interactivity) with carbon black.
The functional group having an affinity for the filler preferably contains at least one selected from the group consisting of oxygen atoms, silicon atoms, and nitrogen atoms, and is selected from the group consisting of oxygen atoms and silicon atoms. It is more preferable to contain at least one and a nitrogen atom, and further preferably to contain all of an oxygen atom, a silicon atom, and a nitrogen atom.
Functional groups containing all of the oxygen, silicon, and nitrogen atoms can interact with both silica and carbon black. By changing the content ratio of atoms in the functional group, the affinity of the packing material can be controlled. For example, a functional group containing all of oxygen atoms, silicon atoms, and nitrogen atoms but having a high nitrogen atom content tends to have a high affinity for carbon black. In addition, a functional group containing all of oxygen atoms, silicon atoms, and nitrogen atoms but having a high content ratio of oxygen atoms and silicon atoms tends to have a high affinity for silica.
As the modified conjugated diene polymer (A-2), a modified conjugated diene polymer having a functional group having an affinity for both silica and carbon black may be used, or a functional group having an affinity for silica may be used. A modified conjugated diene polymer having a modified conjugate diene polymer and a modified conjugated diene polymer having a functional group having an affinity for carbon black may be mixed and used.

The modified conjugated diene polymer (A-2) can be obtained by modifying the unmodified conjugated diene polymer (A-3) with a modifying agent. The modifier can be appropriately selected from the above-mentioned known modifiers having a modifying functional group, and is a modifier containing at least one atom selected from a silicon atom, a nitrogen atom and an oxygen atom in one molecule. It is more preferable that the modifier contains at least one selected from the group consisting of an oxygen atom and a silicon atom and a nitrogen atom in one molecule, and all of the oxygen atom, the silicon atom and the nitrogen atom. Is more preferably a modifier containing the above in one molecule.

Since it has high interaction with a filler (for example, silica), the modifier is preferably one or more selected from the group consisting of an alkoxysilane compound, a hydrocarbyloxysilane compound, and a combination thereof.

The alkoxysilane compound is not particularly limited, but is more preferably an alkoxysilane compound represented by the following general formula (I).
R ¹ _a -Si- (OR ² ) _4-a ... (I)
In the general formula (I), R ¹ and R ² independently represent a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, respectively. Is an integer of 0 to 2, and when there are a plurality of OR ² , each OR ² may be the same or different from each other, and the molecule does not contain an active proton.

Specific examples of the alkoxysilane compound represented by the general formula (I) include N- (1,3-dimethylbutylidene) -3-triethoxysilyl-1-propaneamine, tetramethoxysilane, tetraethoxysilane, and tetra. -N-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxy Silane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxysilane, propyltriisopropoxysilane, Butyltrimethoxysilane, butyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimetridimethoxysilane, methylphenyldimethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, divinyldiethoxysilane, etc. Can be mentioned. Among these, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propaneamine, tetraethoxysilane, methyltriethoxysilane, and dimethyldiethoxysilane are preferable. The alkoxysilane compound may be used alone or in combination of two or more.

The hydrocarbyloxysilane compound is preferably a hydrocarbyloxysilane compound represented by the following general formula (II).

In the general formula (II), n1 + n2 + n3 + n4 = 4 (where n2 is an integer of 1 to 4, n1, n3 and n4 are integers of 0 to 3), and A ¹ is a saturated cyclic tertiary amine compound. Residue, unsaturated cyclic tertiary amine compound residue, ketimine residue, nitrile group, (thio) isocyanato group, (thio) epoxy group, isocyanuric acid trihydrocarbyl ester group, dihydrocarbyl carbonate group, nitrile group, pyridine Groups, (thio) ketone groups, (thio) aldehyde groups, amide groups, (thio) carboxylic acid ester groups, metal salts of (thio) carboxylic acid esters, carboxylic acid anhydride residues, carboxylic acid halogen compound residues, and It is at least one functional group selected from a primary or secondary amino group or a mercapto group having a hydrolyzable group, and may be the same or different when n4 is 2 or more, and A ¹ is , Si may be a divalent group that combines with Si to form a cyclic structure, and R ²¹ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group having 6 to 18 carbon atoms. It is a monovalent aromatic hydrocarbon group and may be the same or different when n1 is 2 or more. R ²³ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms. It is a monovalent aromatic hydrocarbon group or halogen atom having 6 to 18 carbon atoms, and may be the same or different when n3 is 2 or more. R ²² is a monovalent fat having 1 to 20 carbon atoms. It is a group or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, both of which may contain a nitrogen atom and / or a silicon atom, and when n2 is 2 or more. May be the same or different from each other, or they form a ring together, and R ²⁴ is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or 6 carbon atoms. It is a divalent aromatic hydrocarbon group of ~ 18, and may be the same or different when n4 is 2 or more.

As the hydrolyzable group in the primary or secondary amino group having a hydrolyzable group or the mercapto group having a hydrolyzable group, a trimethylsilyl group or a tert-butyldimethylsilyl group is preferable, and a trimethylsilyl group is particularly preferable.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (III).

In the general formula (III), p1 + p2 + p3 = 2 (where p2 is an integer of 1 to 2 and p1 and p3 are integers of 0 to 1), A ² is NRa (Ra is monovalent). (Hydrocarbon group, hydrolyzable group or nitrogen-containing organic group) or sulfur, ^R25 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or 6 to 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of 18, in which R27 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to ²⁰ carbon atoms and a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. Alternatively, it is a halogen atom, and ^R26 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a nitrogen-containing organic group. , Both may contain a nitrogen atom and / or a silicon atom, and when p2 is 2, they may be the same or different from each other, or together form a ring, R ²⁸ . Is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. As the hydrolyzable group, a trimethylsilyl group or a tert-butyldimethylsilyl group is preferable, and a trimethylsilyl group is particularly preferable.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (IV) or (V).

In the general formula (IV), q1 + q2 = 3 (where q1 is an integer of 0 to 2 and q2 is an integer of 1 to 3), and R ³¹ is a divalent aliphatic having 1 to 20 carbon atoms. Alternatively, it is an alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and R ³² and R ³³ are independently hydrolyzable groups and monovalent fats having 1 to 20 carbon atoms, respectively. A group or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and R ³⁴ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group or a carbon number of carbon atoms. It is a monovalent aromatic hydrocarbon group of 6 to 18, and may be the same or different when ^q1 is 2, and R35 is a monovalent aliphatic or alicyclic hydrocarbon having 1 to 20 carbon atoms. It is a group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be the same or different when q2 is 2 or more.
q1 is preferably 1 or more, and more preferably 1.
R ³¹ is preferably a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, and more preferably a divalent aliphatic hydrocarbon group having 2 to 5 carbon atoms.
R ³² and R ³³ are preferably hydrolyzable groups, and as the hydrolyzable group, a trimethylsilyl group or a tert-butyldimethylsilyl group is preferable, and a trimethylsilyl group is particularly preferable. Each of R ³⁴ and R ³⁵ is preferably a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, and more preferably a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms. preferable.

In the general formula (V), r1 + r2 = 3 (where r1 is an integer of 1 to 3 and r2 is an integer of 0 to 2), and R ³⁶ is a divalent aliphatic having 1 to 20 carbon atoms. Alternatively, it is an alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and R ³⁷ is a dimethylaminomethyl group, a dimethylaminoethyl group, a diethylaminomethyl group, a diethylaminoethyl group, or a methylsilyl (methyl). Aminomethyl group, methylsilyl (methyl) aminoethyl group, methylsilyl (ethyl) aminomethyl group, methylsilyl (ethyl) aminoethyl group, dimethylsilylaminomethyl group, dimethylsilylaminoethyl group, monovalent fat having 1 to 20 carbon atoms It is a group or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be the same or different when r1 is 2 or more, and R ³⁸ has 1 to 20 carbon atoms. Hydrocarbyloxy group, monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, even if r2 is 2. It may be different.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound having two or more nitrogen atoms represented by the following general formula (VI) or (VII). As a result, the filler is likely to be unevenly distributed in the modified conjugated diene polymer (A-2) phase, and the wear resistance and low heat generation (low loss) of the vulcanized rubber and the tire can be further improved.

^In the general formula (VI), TMS is a trimethylsilyl group, R40 is a trimethylsilyl group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic group having 6 to 18 carbon atoms. A hydrocarbon group, R ⁴¹ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon having 6 to 18 carbon atoms. It is a hydrogen group, and R ⁴² is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.

In the general formula (VII), TMS is a trimethylsilyl group, and ^R43 and ^R44 are independently divalent aliphatic or alicyclic hydrocarbon groups having 1 to 20 carbon atoms or 2 carbon atoms 6 to 18 respectively. Valuable aromatic hydrocarbon groups, R ⁴⁵ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. R ⁴⁵ may be the same or different.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (VIII).

In the general formula (VIII), r1 + r2 = 3 (where r1 is an integer of 0 to 2 and r2 is an integer of 1 to 3), TMS is a trimethylsilyl group, and ^R46 has 1 to 3 carbon atoms. It is a divalent aliphatic or alicyclic hydrocarbon group of 20 or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and R ⁴⁷ and R ⁴⁸ are independently monovalent with 1 to 20 carbon atoms, respectively. It is an aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. The plurality of R ^47s or R ^48s may be the same or different.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (IX).

In the general formula (IX), Y is a halogen atom and R ⁴⁹ is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. R ⁵⁰ and R ⁵¹ are independently hydrolyzable groups, monovalent aliphatic or alicyclic hydrocarbon groups having 1 to 20 carbon atoms, or monovalent aromatic hydrocarbons having 6 to 18 carbon atoms. It is a group, or R ⁵⁰ and R ⁵¹ are bonded to form a divalent organic group, and R ⁵² and R ⁵³ are independently halogen atoms, hydrocarbyloxy groups, and 1 to 20 carbon atoms, respectively. It is a monovalent aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. The R ⁵⁰ and R ⁵¹ are preferably hydrolyzable groups, and as the hydrolyzable group, a trimethylsilyl group or a tert-butyldimethylsilyl group is preferable, and a trimethylsilyl group is particularly preferable.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound having a structure represented by the following general formulas (X) to (XIII).

In the general formulas (X) to (XIII), the symbols U and V are integers satisfying 0 to 2 and U + V = 2, respectively. R ⁵⁴ to R ⁵⁶ , R ⁶⁰ to R ⁶⁶ , R ⁶⁸ to R ⁷⁰ , R ⁷² to R ⁷⁶ , R ⁷⁹ , R ⁸⁰ , R ⁸² , R ⁸³ , and R ⁸⁵ in the general formulas (X) to (XIII). ~ R ⁹¹ may be the same or different, and is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. R ⁵⁷ to R ⁵⁹ , R ⁶⁷ , R ⁷¹ , R ⁷⁷ , R ⁷⁸ , R ⁸¹ , R ⁸⁴ , and R ⁹² in the general formulas (X) to (XIII) may be the same or different, and have 1 carbon atom. It is a divalent aliphatic or alicyclic hydrocarbon group of about 20 or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. Α and β in the general formula (XIII) are integers of 0 to 5.

Among the compounds of the general formula (IV), [N, N-bis (trimethylsilyl)-(3-amino-1-propyl)] (methyl) (diethoxy) silane is preferable.
Among the compounds of the general formulas (X) to (XII), N1, N1, N7-tetramethyl-4-((trimethoxysilyl) methyl) -1,7 heptan, 2-((hexyl-dimethoxysilyl) methyl) ) -N1, N1, N3, N3-2-pentamethylpropan-1,3-diamine, N1- (3- (dimethylamino) propyl-N3, N3-dimethyl-N1- (3- (trimethoxysilyl) propyl) ) Propane-1,3-diamine, 4- (3- (dimethylamino) propyl) -N1, N1, N7, N7-tetramethyl-4-((trimethoxysilyl) methyl) heptane-1,7-diamine Is preferable.

Among the compounds of the general formula (XIII), N, N-dimethyl-2- (3- (dimethoxymethylsilyl) propoxy) ethaneamine, N, N-bis (trimethylsilyl) -2- (3- (trimethoxysilyl) propoxy) ) Ethanamine, N, N-dimethyl-2- (3- (trimethoxysilyl) propoxy) ethaneamine, N, N-dimethyl-3- (3- (trimethoxysilyl) propoxy) propan-1-amine are preferred.

The hydrocarbyloxysilane compounds represented by the above general formulas (II) to (XIII) are modified from the unmodified conjugated diene polymer (A-3) to obtain the modified conjugated diene polymer (A-2). Although described as a denaturant for this purpose, it may be used as a denaturant for a non-conjugated diene polymer (A-4) and any other polymer component.

The hydrocarbyloxysilane compound represented by the general formulas (II) to (XIII) is preferably an alkoxysilane compound.

Suitable modifiers for obtaining modified rubber by anionic polymerization include, for example, 3,4-bis (trimethylsilyloxy) -1-vinylbenzene, 3,4-bis (trimethylsilyloxy) benzaldehyde, and 3,4-bis ( Included are at least one compound selected from tert-butyldimethylsilyloxy) benzaldehyde, 2-cyanopyridine, 1,3-dimethyl-2-imidazolidinone, tin tetrachloride, and 1-methyl-2-pyrrolidone.

The modifier is preferably an amide moiety of a lithium amide compound used as a polymerization initiator in anionic polymerization. Examples of such lithium amide compounds include lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium dodecamethyleneimide, lithium dimethylamide, lithium diethylamide, lithium dibutylamide, and lithium dipropyl. Amide, Lithiumdiheptylamide, Lithiumdihexylamide, Lithiumdioctylamide, Lithiumdi-2-ethylhexylamide, Lithiumdidecylamide, Lithium-N-methylpiberazide, Lithiumethylpropylamide, Lithiumethylbutylamide, Lithiumethylbenzylamide, Lithiummethyl Examples include phenethylamide and combinations thereof. For example, the modifier that becomes the amide moiety of lithium hexamethyleneimide is hexamethyleneimine, the modifier that becomes the amide moiety of lithium pyrrolidine is pyrrolidine, and the modifier that becomes the amide moiety of lithium piperidine is piperidine. ..

Suitable modifiers for obtaining the modified conjugated diene polymer (A-2) by coordination polymerization include, for example, at least one compound selected from 2-cyanopyridine and 3,4-ditrimethylsilyloxybenzaldehyde. Can be mentioned.

When the modified conjugated diene polymer (A-2) is obtained by emulsion polymerization, a suitable modifier is, for example, at least one selected from 3,4-ditrimethylsilyloxybenzaldehyde and 4-hexamethyleneiminoalkylstyrene. Examples include compounds. These modifiers, which are preferably used in emulsion polymerization, are preferably copolymerized during emulsion polymerization as a monomer containing a nitrogen atom and / or a silicon atom.

The modification rate of the modified conjugated diene polymer (A-2) is not particularly limited and may be appropriately selected depending on the intended purpose. The modification rate is, for example, preferably 30% or more, more preferably 35% or more, and particularly preferably 70% or more. This allows the filler to be selectively present in the modified conjugated diene polymer (A-2) phase.

[Carbon black (B)]
The rubber composition of the present invention contains carbon black (B) having a specific surface area of cetyltrimethylammonium bromide (CTAB) of 20 to 195 m ² / g.
If the CTAB specific surface area of carbon black is less than 20 m ² / g, the wear resistance is not excellent, and if it exceeds 195 m ² / g, the low heat generation is not excellent. From the viewpoint of further improving the wear resistance, the CTAB specific surface area of carbon black is preferably 50 m ² / g or more, and more preferably 70 m ² / g or more. Further, from the viewpoint of further improving low heat generation, the CTAB of carbon black is preferably 150 ² / g or less, and more preferably 130 m ² / g or less.
The CTAB specific surface area of carbon black can be measured by a method according to JIS K 6217-3: 2001 (How to determine the specific surface area-CTAB adsorption method).

The type of carbon black is not particularly limited as long as the CTAB specific surface area is within the above range, and examples thereof include GPF, FEF, HAF, ISAF, and SAF.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 70 m ² / g or more. When the N ₂ SA of carbon black is 70 m ² / g or more, the wear resistance of the crosslinked rubber and the tire can be further improved. The N ₂ SA of carbon black is preferably 140 m ² / g or less. When it is 140 m ² / g or less, the dispersibility of carbon black in the rubber composition is excellent.
The carbon black N ₂ SA is obtained by the A method of JIS K 6217-2: 2001 (method of determining specific surface area-nitrogen adsorption method-single point method).

The dibutyl phthalate oil absorption (DBP oil absorption) is preferably 70 ml / 100 g or more. When the DBP oil absorption of carbon black is 70 ml / 100 g or more, the wear resistance of the crosslinked rubber and the tire can be further improved. Further, from the viewpoint of processability of the rubber composition, the DBP oil absorption amount of carbon black is preferably 140 ml / 100 g or less.
The DBP oil absorption amount of carbon black is determined by JIS K 6217-4: 2001 (how to determine the oil absorption amount).

The total amount of the carbon black (B) content (b) and the silica (C) content (c) of the carbon black (B) is 30 to 80 mass with respect to 100 parts by mass of the rubber component (A). Part, the ratio of the carbon black (B) content (b) and the silica (C) content (c) is based on mass, (b): (c) = 70 to 85:30 to 15 It is contained in the rubber composition in the range of.
Hereinafter, the total amount [= (b) + (c)] of the content (b) and the content (c) may be referred to as "total amount (d)".
If the total amount (d) is less than 30 parts by mass with respect to 100 parts by mass of the rubber component (A), the wear resistance of the crosslinked rubber and the tire cannot be obtained, and if it exceeds 80 parts by mass, the crosslinked rubber is low. It is not excellent in heat generation and is not excellent in low loss property of tires.
The total amount (d) preferably exceeds 30 parts by mass with respect to 100 parts by mass of the rubber component (A), and is preferably 35 parts by mass or more, from the viewpoint of further improving the wear resistance of the crosslinked rubber and the tire. More preferred. The total amount (d) is preferably 70 parts by mass or less, and 55 parts by mass with respect to 100 parts by mass of the rubber component (A), from the viewpoint of further improving the low heat generation of the crosslinked rubber and the low loss property of the tire. The following is more preferable.

[Silica (C)]
The rubber composition of the present invention contains silica (C) having a specific surface area of cetyltrimethylammonium bromide (CTAB) of 200 m ² / g or more.
If the CTAB specific surface area of silica (C) is less than 200 m ² / g, the wear resistance of the vulcanized rubber and the tire is not excellent. The upper limit of the CTAB specific surface area of silica (C) is not particularly limited, but at present, products exceeding 250 m ² / g are not available.
The CTAB specific surface area of silica (C) is preferably 210 m ² / g or more from the viewpoint of further improving the wear resistance of the vulcanized rubber and the tire.
The CTAB specific surface area of silica (C) can be measured by a method according to the method of ASTM-D3765-80.

The silica (C) is not particularly limited as long as it has a CTAB specific surface area of 200 m ² / g or more, and examples thereof include wet silica (hydrous silicic acid), dry silica (silicic anhydride), and corodal silica.
Silica having a CTAB specific surface area of 200 m ² / g or more may be a commercially available product, and can be obtained, for example, as Zeosil Premium 200MP (trade name) of Rhodia and 9500GR (trade name) of Evonik.

The total amount (d) of the carbon black (B) content (b) and the silica (C) content (c) of the silica (C) is 30 to 30 parts by mass with respect to 100 parts by mass of the rubber component (A). It is 80 parts by mass, and the ratio of the carbon black (B) content (b) and the silica (C) content (c) is based on mass, (b): (c) = 60 to 85:40. It is contained in the rubber composition in the range of up to 15.
The numerical range of this ratio is the silica (= (b) + (c)] in the total amount (d) [= (b) + (c)] of the content (b) of carbon black (B) and the content (c) of silica (C). It means that the content ratio of C) is 15 to 40% by mass.
If the content ratio of silica (C) in the total amount (d) is less than 15% by mass, it becomes difficult to improve low heat generation without impairing wear resistance, and if it exceeds 40% by mass, wear resistance decreases. There is a risk of
The content ratio of silica (C) in the total amount (d) is preferably 30% by mass or less.

The filler may contain a filler other than carbon black (B) and silica (C), and examples of such a filler include metal oxides such as alumina and titania.
The ratio of the content (b) of carbon black (B) to the content (c) of silica (C) even when the filler contains a filler other than carbon black (B) and silica (C). [(B): (c)] is 60 to 85:40 to 15, preferably 70 to 85:30 to 15 on a mass basis.

[Silane coupling agent]
The rubber composition of the present invention contains a modified conjugated diene polymer (A-2), but after strengthening the bond between the silica and the rubber component to further enhance the reinforcing property of the rubber composition, the silica In order to improve dispersibility, the rubber composition of the present invention may further use a silane coupling agent.
The content of the silane coupling agent in the rubber composition of the present invention is preferably 5 to 15% by mass or less with respect to the content of silica. When the content of the silane coupling agent is 15% by mass or less with respect to the content of silica, the effect of improving the reinforcing property and the dispersibility of the rubber component can be obtained, and the economic efficiency is not easily impaired. Further, when the content of the silane coupling agent is 5% by mass or more with respect to the content of silica, the dispersibility of silica in the rubber composition can be enhanced.

The silane coupling agent is not particularly limited, and is bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) tetrasulfide, and bis. (3-Trimethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) disulfide, bis (2-tri) Ethoxysilylethyl) trisulfide, bis (2-triethoxysilylethyl) tetrasulfide, 3-trimethoxysilylpropylbenzothiazole disulfide, 3-trimethoxysilylpropylbenzothiazole trisulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide Etc. are preferably mentioned.

(Various ingredients)
In addition to the rubber component (A), carbon black (B) and silica (C) described above, and the silane coupling agent contained as necessary, the rubber composition of the present invention includes, for example, a vulcanizing agent and a addition. Various components usually used in the rubber industry, such as a vulcanization accelerator, zinc oxide, stearic acid, and an antioxidant, can be appropriately selected and blended within a range that does not impair the object of the present invention. Commercially available products can be preferably used as these various components. Further, the rubber composition is a closed-type mixture of a rubber component, carbon black (B), silica (C), and various components selected as appropriate, such as a Banbury mixer, an internal mixer, and an intensive mixer. It can be prepared by kneading using a kneading device, a non-sealed kneading device such as a roll, or the like, and then heating, extruding, or the like.
Since the rubber composition of the present invention contains a modified conjugated diene polymer (A-2) having a functional group having an affinity for the filler, the filler and the modified conjugated diene polymer (A-2) When the rubber composition is kneaded, the agglomerates of the filler can be loosened. Therefore, it is easy to improve the low heat generation of the vulcanized rubber and the tire.

<Vulcanized rubber, tires>
The vulcanized rubber of the present invention is a rubber obtained by vulcanizing the rubber composition of the present invention, and is excellent in low heat generation without impairing wear resistance. Therefore, the vulcanized rubber of the present invention can be used for various rubber products such as tires, anti-vibration rubbers, seismic isolation rubbers, belts such as conveyor belts, rubber crawlers, and various hoses.
For example, when the vulcanized rubber of the present invention is used for a tire, the structure of the tire is not particularly limited as long as the rubber composition of the present invention is used, and can be appropriately selected depending on the intended purpose. Such a tire is excellent in low loss property without impairing wear resistance.

The application site of the rubber composition of the present invention in a tire is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a tire case, a tread, a base tread, a sidewall, a side reinforcing rubber, a bead filler and the like. Can be mentioned.
As a method for manufacturing the tire, a conventional method can be used. For example, members usually used for tire manufacturing such as a carcass layer, a belt layer, and a tread layer made of the rubber composition and cord of the present invention are sequentially laminated on a tire forming drum, and the drum is removed to obtain a green tire. Then, the green tire is heated according to a conventional method and vulcanized to produce a desired tire (for example, a pneumatic tire).

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

<Preparation of rubber composition>
Using the rubber components shown in Table 1, carbon black, and silica, a rubber composition having a formulation shown in Table 2 was prepared according to a conventional method.

[Details of each component in Table 1]
Details of each component excluding the rubber component (A), carbon black, and silica in Table 1 are as follows.
Silane coupling agent: manufactured by Shin-Etsu Chemical Co., Ltd., ABC-856
Sulfur: Made by Tsurumi Kagakusha Co., Ltd., trade name "powdered sulfur"
Vulcanization accelerator: N-cyclohexyl-2-benzothiazolyl sulfeneamide, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Noxeller CZ-G"
Stearic acid: Made by Shin Nihon Rika Co., Ltd., trade name "Stearic acid 50S"
Zinc Oxide: Made by HakusuiTech Co., Ltd., trade name "No. 3 Zinc Oxide"
Anti-aging agent: N-Phenyl-N'-(1,3-dimethylbutyl) -p-phenylenediamine, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Nocrack 6C"

[Details of each component in Table 2]
1. 1. Rubber component (A)
Natural rubber (A-1): RSS # 1
Modified BR1 (A-2): Modified conjugated diene polymer produced by the following production method Modified BR2 (A-2): Modified conjugated diene polymer produced by the following production method Unmodified BR (A-3): Polybutadiene Rubber, manufactured by Asahi Kasei Co., Ltd., product name "NF35R"
Regarding the above rubber components, natural rubber (A-1) and modified BR1 (A-2); natural rubber (A-1) and modified BR2 (A-2); natural rubber (A-1) and unmodified BR (A). It was confirmed that -3) were incompatible with each other. Specifically, with respect to the rubber compositions of Examples and Comparative Examples, a region of 4 μm × 4 μm of the rubber composition was observed using FIB / SEM, and it was confirmed that there was a difference in the dyeing condition.

(Manufacturing method of modified BR1)
To a dry, nitrogen-substituted 800 ml pressure-resistant glass container, add 1,3-butadiene cyclohexane solution to 83.1 g of 1,3-butadiene to make 8,2-ditetrahydrofurylpropane 0.04 mmol. Was added, 0.8 mmol of a lithium amide compound prepared in advance by adjusting n-butyllithium and hexamethyleneimine in a molar ratio of 1: 1 was added, and then polymerization was carried out at 50 ° C. for 3 hours. At this time, 0.48 mmol of tin tetrachloride was added to the polymerization reaction system in which the polymerization conversion rate was almost 100%, and a modification reaction was carried out at 50 ° C. for 30 minutes. Then, 2 ml of an isopropanol 5% by mass solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, and the mixture was dried according to a conventional method to obtain a modified polymer A.
Moreover, as a result of measuring the microstructure of the obtained polymer, the vinyl bond amount of the butadiene portion was 14%, and the polystyrene-equivalent peak molecular weight obtained by gel permeation chromatography was 200,000.

(Manufacturing method of modified BR2)
In an 800 ml pressure-resistant glass container that has been dried and replaced with nitrogen, a cyclohexane solution of 1,3-butadiene, added to 83.1 g of 1,3-butadiene, and 0.16 mmol of 2,2-ditetrahydrofurylpropane are added. In addition, 0.8 mmol of n-butyllithium was added, and then polymerization was carried out at 50 ° C. for 2 hours. In this case, 0.72 of [N, N-bis (trimethylsilyl)-(3-amino-1-propyl)] (methyl) (diethoxy) silane was added to the polymerization reaction system in which the polymerization conversion rate was almost 100%. Mmol was added and a modification reaction was carried out at 50 ° C. for 30 minutes. Then, 2 ml of a solution of 2,6-di-t-butyl-p-cresol (BHT) in 5% by mass of isopropanol was added to stop the reaction, and the mixture was dried according to a conventional method to obtain a modified polymer B.
Moreover, as a result of measuring the microstructure of the obtained polymer, the vinyl bond amount of the butadiene portion was 30%, and the polystyrene-equivalent peak molecular weight obtained by gel permeation chromatography was 200,000.

2. Filler CB (B): Carbon black, manufactured by Asahi Carbon Co., Ltd., trade name "Asahi # 78" (CTAB: 122m ² / g)
Silica 1: Made by Nippon Silica Industry Co., Ltd., trade name "Nip Seal AQ" (CTAB: 150m ² / g)
Silica 2: Made by Evonik, trade name "9500GR" (CTAB: 220m ² / g)

<Manufacturing and evaluation of tires>
A tire (tire size: 195 / 65R15) was prototyped using the prepared rubber composition as a tire case rubber, and vulcanized rubber was cut out from the prototype tire to evaluate the wear resistance and low heat generation of the vulcanized rubber. The results are shown in Table 2.

(1) Abrasion resistance A runbone wear test was conducted on each vulcanized rubber sample. Abrasion resistance was evaluated at room temperature (23 ° C.) according to the standard test conditions of the Rambone wear test specified in JIS K 6264-2: 2005.
Regarding the evaluation, the reciprocal of the amount of wear when the reciprocal of the amount of wear of the vulture rubber sample of Comparative Example 1 is 100 is shown as an index, and the larger the value of the wear resistance index, the better the wear resistance. Indicates that.

(2) For the low heat-generating vulcanized rubber, tan δ was measured at a temperature of 50 ° C., a strain of 3%, and a frequency of 15 Hz using a viscoelasticity measuring device (manufactured by Leometrics). The exponential notation was expressed by the following formula with tan δ of Comparative Example 1 as 100. The smaller the exothermic index, the better the low exotherm and the smaller the hysteresis loss.
Exothermic index = (tan δ of each vulcanized rubber / tan δ of vulcanized rubber of Comparative Example 1) × 100

(3) Evaluation of balance between wear resistance and low heat generation Using the above wear resistance index and heat generation index, the balance index between wear resistance and low heat generation was calculated by the following formula. The larger the balance index, the better the balance between wear resistance and low heat generation.
Balance index = (wear resistance index-100) + (100-low heat generation index)

As is clear from Table 2, the vulcanized rubber cut out from the tire of the example has improved low heat generation property as compared with the vulcanized rubber of the comparative example 1 without impairing the wear resistance. Above all, it was found that the vulcanized rubber of Example 5 was excellent in both wear resistance and low heat generation, and was also excellent in the balance between the two.
Further, as in Comparative Example 2, even if the rubber component contains a modified conjugated diene polymer having a functional group compatible with the filler, the cetyltrimethylammonium bromide specific surface area (CTAB) is 200 m ² / g. The vulcanized rubber of Comparative Example 2 using other silica without using the above silica (C) has a large balance index and improves low heat generation property as compared with the vulcanized rubber of Comparative Example 1. It can be seen that the wear resistance is impaired.

By using the rubber composition of the present invention, a sulfide rubber having excellent low heat generation can be obtained without impairing wear resistance. Therefore, tires using the rubber composition of the present invention are for passenger cars and light passenger cars. , Suitable for tire cases, tread members, etc. of various tires for light trucks and heavy loads {for trucks / buses, off-the-road tires (for mining vehicles, construction vehicles, light trucks, etc.)}.

Claims (10)

Carbon black (B) having a specific surface area of cetyltrimethylammonium bromide of 20 to 195 m ² / g and a specific surface area of nitrogen adsorption of 70 m ² / g or more, and silica having a specific surface area of cetyltrimethylammonium bromide of 200 m ² / g or more ( Filler containing C) and
A rubber component (A) containing at least one isoprene-based rubber (A-1) selected from the group consisting of natural rubber and polyisoprene rubber and a modified conjugated diene-based polymer (A-2),
Including
The modified conjugated diene polymer (A-2) is a modified conjugated diene polymer of one or more conjugated diene polymers (A-3) selected from the group consisting of polybutadiene rubber and styrene-butadiene copolymer rubber. It is a polymer and has one or more modified functional groups selected from the group consisting of a nitrogen-containing functional group, a silicon-containing functional group, and an oxygen-containing functional group.
In the rubber component (A), the content of the isoprene rubber (A-1) is 50 to 85% by mass, and the content of the modified conjugated diene polymer (A-2) is 15 to 50% by mass. can be,
The total amount of the carbon black (B) content (b) and the silica (C) content (c) is 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component (A).
The ratio of the content (b) to the content (c) is (b) :( c) = 60 to 85:40 to 15 on a mass basis.
The content of the unmodified conjugated diene polymer (A-3) in the rubber component (A) is 0 to 20% by mass .
A rubber composition in which the modified conjugated diene polymer (A-2) is modified with one or more modifiers selected from the group consisting of an alkoxysilane compound, a hydrocarbyloxysilane compound, and a combination thereof. In the rubber component (A), the content of the isoprene rubber (A-1) is 60 to 80% by mass, and the content of the modified conjugated diene polymer (A-2) is 20 to 40% by mass. The rubber composition according to claim 1. The ratio of the carbon black (B) content (b) to the silica (C) content (c) is (b) :( c) = 70 to 85:30 to 15 on a mass basis. The rubber composition according to claim 1 or 2. The rubber composition according to any one of claims 1 to 3, wherein the silica (C) has a specific surface area of cetyltrimethylammonium bromide of 210 m ² / g or more. The rubber composition according to any one of claims 1 to 4, wherein the modified functional group contains at least one selected from the group consisting of an oxygen atom and a silicon atom, and a nitrogen atom. The rubber composition according to any one of claims 1 to 5, wherein the carbon black (B) has a specific surface area of cetyltrimethylammonium bromide of 70 m ² / g or more. The rubber composition according to any one of claims 1 to 6, wherein the alkoxysilane compound is an alkoxysilane compound represented by the following general formula (I).
R ¹ _a -Si- (OR ² ) _4-a ... (I)
[In the general formula (I), R ¹ and R ² independently represent a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, respectively. a is an integer of 0 to 2, and when there are a plurality of OR ² , each OR ² may be the same or different from each other, and the molecule does not contain an active proton. ] The rubber composition according to any one of claims 1 to 7, wherein the hydrocarbyloxysilane compound is a hydrocarbyloxysilane compound represented by the following general formula (II).

[In the general formula (II), n1 + n2 + n3 + n4 = 4 (where n2 is an integer of 1 to 4, n1, n3 and n4 are integers of 0 to 3), and A ¹ is a saturated cyclic tertiary amine. Compound residue, unsaturated cyclic tertiary amine compound residue, ketimine residue, nitrile group, (thio) isocyanato group, (thio) epoxy group, isocyanuric acid trihydrocarbyl ester group, dihydrocarbyl carbonate group, nitrile group, Pyridine group, (thio) ketone group, (thio) aldehyde group, amide group, (thio) carboxylic acid ester group, metal salt of (thio) carboxylic acid ester, carboxylic acid anhydride residue, carboxylic acid halogen compound residue, In addition, it is at least one functional group selected from a primary or secondary amino group or a mercapto group having a hydrolyzable group, and when n4 is 2 or more, it may be the same or different, and A ¹ May be a divalent group that binds to Si to form a cyclic structure, and R ²¹ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group having 6 to 18 carbon atoms. It is a monovalent aromatic hydrocarbon group and may be the same or different when n1 is 2 or more. R ²³ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms. , A monovalent aromatic hydrocarbon group or halogen atom having 6 to 18 carbon atoms, which may be the same or different when n3 is 2 or more, and R ²² is a monovalent aromatic hydrocarbon group having 1 to 20 carbon atoms. It is an aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, both of which may contain a nitrogen atom and / or a silicon atom, and when n2 is 2 or more. May be the same or different from each other, or together to form a ring, and R ²⁴ is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or an alicyclic hydrocarbon group or a carbon number of carbon atoms. It is a divalent aromatic hydrocarbon group of 6 to 18, and may be the same or different when n4 is 2 or more. ] The rubber composition according to any one of claims 1 to 8 , wherein the conjugated diene-based polymer (A-3) is a polymer polymerized using a lithium amide compound as a polymerization initiator. A tire using the rubber composition according to any one of claims 1 to 9 .