JPH10292066A - Rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition which undergoes little the separation of the compounded high-hardness material and gives a tire exhibiting stable braking performance on ice and excellent durability when used as e.g. tire tread rubber and to provide a pneumatic tire made therefrom. SOLUTION: This composition contains 3-30 pts.wt. composite material prepared by previously allowing the surface of a porous material made of a material having a JIS-C hardness of 75 or above and having a means particle diameter of 5-3,000 μm to absorb a diene rubber or a diene rubber composition per 100 pts.wt. total diene rubber component (including also the diene rubber absorbed by the composite material or the diene rubber in the diene rubber compounded rubber composition). The objective tire is prepared by using the rubber composition as a tread rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition and a pneumatic tire, and more particularly, to a tire tread for all vehicles from small to large, such as passenger cars, trucks and buses, having a high coefficient of friction on ice after vulcanization. Others that can be suitably used as rubber, shoe soles, rubber mats,
The present invention relates to a rubber composition which can be suitably used for a rubber product such as a caterpillar which requires a non-slip function in cold regions, and a pneumatic tire using the same as a tread rubber.

[0002]

2. Description of the Related Art In recent years, demand for so-called all-season tires, which can be used in the same manner as in summer without replacing tires in winter, has been increasing. This type of tire has the same dry grip, wet grip, steering stability, durability, and fuel economy in winter as in summer, and has sufficient driving and braking performance on ice and snow. It is.

[0003] Conventional tread rubbers used for such tires are required to have low hardness at low temperature of tread rubber for summer, and use a polymer having a low glass transition point or an elastic modulus at low temperature. There is known a method of using a softening agent capable of appropriately maintaining the temperature.

[0004] However, in the former method, due to the hysteresis characteristic of the polymer, even if the performance is moderate in the ice and snow temperature range, the braking performance and the maneuverability on wet and dry road surfaces are not sufficient. And the latter method is also disclosed in JP-A-55-135149, JP-A-58-199203, JP-A-60-137945, etc.
It has been pointed out that the improvement of the performance on ice and snow has a large adverse effect on abrasion resistance and durability when driving on a general road.

[0005] In any of the techniques, although good performance is obtained in the so-called dry-on-ice ice performance in a relatively low temperature region of -5 ° C or less, the temperature is close to 0 ° C. In the performance on ice in a wet state, so-called wet-on-ice, a sufficient coefficient of friction could not be obtained, and it was hard to say that the drivability, braking performance and steering stability were sufficiently improved.

On the other hand, in recent years, a technique has been adopted in which tread rubber itself is modified to improve the frictional force. As a first method, there is a method in which a tread rubber is foamed by an appropriate method to generate closed cells (JP-A-63-89547). Generally, a layer called a pseudo liquid layer exists on the surface of ice. Then, when the object is pressed and slid on the ice, the pseudo liquid layer partially changes to a water film, and this water film plays a role of a lubricant, and exhibits a low coefficient of friction.

[0007] The surface of the tread rubber obtained by generating closed cells is covered with a large number of bubbles, so that a water film generated on the surface in contact with the ice surface is removed, and the micropores in the pores are removed. Due to the movement, the effect of removing the pseudo liquid layer (scraper) is exerted, thereby increasing the friction on ice. Generally, tires for ice and snow are designed to increase the edge of the block by providing a large number of sipes, but the essential point is that the pseudo liquid on the ice surface is the edge of the block sipe. It has the function of removing layers, and this effect is called "macro edge effect". On the other hand, microscopic irregularities are created by the closed-cell rubber, and the essence of the function of the convexities is the “microscopic edge effect”.

This technique has been incorporated into actual tire treads and is commercially available as studless tires.
In addition, a method of mixing various foreign substances (natural substances such as sand and rice husk) into the tread rubber and causing the foreign substances to fall off during tire running to generate pores has been studied. This method is the same as foaming as a mechanism for increasing friction on ice. However, although these first methods have the effect of removing the pseudo liquid layer on the ice surface,
Unlike the method of obtaining high friction by scratching the ice solid itself as in conventional spike tires,
It is not satisfactory in terms of performance. That is, the surface of the ice after the foamed or mixed foreign matter of the tread rubber has been detached is scratched on the surface of the ice, and the concave surface absorbs and drains water on the surface, but the ice becomes harder and the surface of the ice becomes harder. At low temperatures (usually −3 ° C. or less) in which the water does not easily dissolve, the water absorption / drainage function is not so required, and the scratching effect cannot be expected much.

As a second method, there is a method in which various high-hardness materials are mixed into tread rubber, and the tread rubber is made to have high wear on ice by utilizing a scratching effect on the surface of the high-hardness material. Yes (Japanese Patent Publication No. 46-3173)
No. 2, JP-A-51-147803, JP-B-56-52
057, JP-A-6-102737). This method is a method for increasing the friction of the tread rubber on ice by a mechanism different from the first method. In fact,
In many cases, the more these hard materials are mixed, the higher the friction of the tread rubber on ice.

However, the disadvantage of the second method of mixing a high-hardness material having a high scratching effect into the matrix rubber of the tread is that the effect of improving the performance on ice near 0 ° C. where the water content is high is small, and the high-hardness material is added to the rubber. Since it exists as a foreign substance having no affinity, wear resistance and destructive characteristics are significantly reduced.

In view of such a situation, the inventor aims to improve performance especially on a icy and snowy road surface in a wet state,
n-1,2-polybutadiene resin and sulfur, a vulcanization accelerator,
A study was conducted to obtain composite particles containing carbon black and an anti-scorch agent, and to mix them with foamed tread rubber from the viewpoint of compatibility with abrasion resistance, but it was still insufficient from the level required by the general market. Nevertheless, further improvement is required. In addition, since the actual ice surface temperature varies from daytime to nighttime, a tire tread that exhibits more stable on-ice performance in a wide temperature range and does not significantly reduce wear resistance and breaking characteristics is desired. ing.

Further, the conventional foamed rubber has a function of improving the coefficient of friction on ice by flowing off a water film generated between the tire and the ice road surface such as a water removal / drainage effect. There is a limit to removing a large amount of water film in the wet-on-ice condition.
At present, it is difficult to improve the friction coefficient on ice in the ice state. On the other hand, another method for improving performance on ice, in which particles having a specific particle size and hardness are added as microspikes to impart a scratching effect, is improved to some extent on wet-on-ice conditions. There is effect, but there is little synergistic effect of scratching effect and drainage effect,
Performance levels on ice were not yet satisfactory.

The reason why the synergistic effect is small is that, in the second method, there is an inverse relationship between the hardness of the particles and the adhesiveness. That is, in the prior art, the harder the particles, the greater the scratching effect, but the harder the material, the lower the adhesiveness with the rubber matrix. The number of spikes decreases, the scratching effect does not last for a long time, and the abrasion resistance and crack resistance are reduced. Furthermore, the hard particles as described above are
When added to the foaming agent compounded rubber, foaming occurs at the particle interface, and the adhesion to the matrix is reduced.

[0014]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-hardness material which is hardly detached, exhibits a stable braking performance on ice when used as a tread rubber of a tire, and has an excellent performance. An object of the present invention is to provide a rubber composition that imparts durability and a pneumatic tire using the same.

[0015]

In order to achieve the above objects, the rubber compositions of the present invention are as follows. (1) A composite made of a material having a JIS-C type hardness of 75 or more and having a porous body having an average diameter of 5 to 3000 μm on which an adsorbing component including a diene-based high molecular weight material is previously adsorbed is a total diene. A rubber composition characterized by being mixed in an amount of 3 to 30 parts by weight with respect to 100 parts by weight of a system rubber component (including a diene rubber in the adsorption component).

(2) In the rubber composition, the average pore diameter of the surface of the porous body is 40 to 1000 °, and BE
It is a rubber composition having a specific surface area of 10 to 800 m ² / g by T nitrogen adsorption method.

(3) The composite has at least one of diene rubber, a rubber composition containing a diene rubber, resorcinol formalin latex, syn-1,2-polybutadiene resin, and a carbon-containing composition thereof. Is a rubber composition.

(4) In the rubber composition, the porous body has a silicon-bonded hydroxyl group (Si-OH) and / or an aluminum-bonded hydroxyl group (Al-OH) on the surface.

(5) In the rubber composition, the adsorption component has a general formula: Y ₃ —Si—C _n H _2n A (where Y is an alkyl group having 1 to 4 carbon atoms, an alkoxyl group or a chlorine atom) And the three Ys may be the same or different,
n represents an integer of 1 to 6, A is _-S m _C n _H 2n Si-
Y is ₃ group and -S m _Z group selected from the group consisting of groups, wherein Z is M is an integer of 1 to 6, and Y and n are as described above. This is a rubber composition containing a coupling agent represented by the formula (1).

(6) The rubber composition according to the present invention, wherein carbon black and / or a vulcanization accelerator are blended in the adsorbed component.

(7) The rubber composition is a foamable rubber composition.

(8) A pneumatic tire characterized in that the rubber composition is used as a tread rubber.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
As the rubber component used in the present invention, those commonly used as tread rubber can be used, for example, natural rubber (NR), isoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), Butadiene rubber (BR), butyl rubber (IIR) and the like can be used alone or in a blend.

Further, in the present invention, it is specified that the hardness of the material to be used, which is measured by a JIS-K6301-C type hardness tester, is 75 degrees or more, before the pulverization of the porous material. If it is less than 75 degrees, a sufficient scratching effect cannot be obtained. Preferably it is 90 or more, most preferably 95 or more.

The average diameter of the porous body is 5 to 30.
It is specified that the thickness is less than 00 μm, because if it is less than 5 μm, a sufficient scratching effect cannot be obtained.
If the thickness exceeds 3000 μm, the force received by the porous body from the road surface is superior to the adhesive force, and the porous body is detached, so that the scratching effect cannot be obtained. Preferably the average diameter is 10
2500 μm.

The average diameter was measured to be 500 μm.
NIKKISO manufactured by Nikkiso Co., Ltd. for the following particles
Using a Microtrac MKII particle size analyzer, laser diffraction measurement (light scattering method) by Microtrac was performed in a usual manner. For particles having an average diameter of 500 μm or more, the particles were classified with a 4 to 30 mesh sieve, and 50%
The particle size corresponding to the weight was defined as the average particle size.

The pores existing on the surface of the porous body preferably have an average pore diameter of 40 to 1000 °. A feature of the porous structure is that a physical anchor effect occurs between the rubber matrix and the rubber matrix, and the rubber matrix is hardly detached. When the average pore diameter of the porous body surface is less than 40 °,
Even if the BET nitrogen adsorption specific surface area satisfies the above range, the rubber composition has low adhesion to the rubber on the surface of the porous body. It is easy to detach on the rubber surface.
On the other hand, if the average pore diameter exceeds 1000 °, the porous body becomes brittle and breaks even if the specific surface area by the BET nitrogen adsorption method satisfies the above range, and a sufficient scratching effect cannot be obtained. More preferably, it is 40 to 300 °.

Although the surface area is increased by being porous, the specific surface area by the BET nitrogen adsorption method is 10 to 80.
0 m ² / g. This is 10 m ² /
If it is less than g, the adhesion of the porous body is insufficient due to the small surface area, and desorption occurs during running. On the other hand, 800 m ² / g
If the amount exceeds the above, the volume of the voids due to the pores of the porous body increases, so that the strength of the porous body itself decreases and the porous body is broken during the contact with the road surface. Preferably, 100 to 600
m ² / g. The BET of the porous material used in the present invention
The specific surface area by the nitrogen adsorption method is determined in accordance with ASTM D3037.

In the rubber composition of the present invention, a composite in which an adsorption component containing a diene-based high molecular weight material is previously adsorbed on the surface of the porous material having the above characteristics. As such a diene-based high molecular weight substance, the same one as the above-mentioned rubber component can be used, and it is also effective to adsorb resorcinol formalin latex, syn-1,2-polybutadiene resin and a carbon-containing composition thereof. . Further, the adsorbing component includes carbon black, silica, stearic acid, Zn which is usually used for rubber compounding.
O, anti-aging agent, thermosetting resin, vulcanization accelerator, vulcanizing agent,
A silane coupling agent or the like can be appropriately compounded.
In addition, for example, the complex is prepared by dissolving a predetermined amount of an adsorbed component in a solvent such as toluene, and adding a porous body to the solution.
After stirring and adsorbing for a predetermined time, the solvent can be distilled off, and further dried by vacuum drying. Such an adsorption method is not limited to the above-mentioned method, and the type of the solvent used, the adsorption temperature, the adsorption time, and the like can be appropriately adjusted. When the adsorbent is latex, the adsorbent may be adsorbed by directly blending with a porous material.

In the present invention, it is important that a specific porous body is compounded in the above-described composite form in the rubber composition. The braking performance on ice is significantly improved,
In addition, good results can be obtained in abrasion resistance and the like.

The amount of the composite is specified to be 3 to 30 parts by weight based on 100 parts by weight of all diene rubber components (including the diene rubber in the adsorbing component).
If the amount is less than 3 parts by weight, a sufficient scratching effect cannot be obtained.
If the amount exceeds 0 parts by weight, durability problem occurs.

In the present invention, the chemical property of the surface of the porous body is represented by the following formula: A silicon-bonded hydroxyl group represented by the following formula and / or Those having an aluminum-bonded hydroxyl group represented by This is because these react easily with the coupling agent according to the present invention and form a primary bond with the polymer, so that a strong adhesive force can be obtained.

Further, in the rubber composition of the present invention,
It is preferable to mix the specific coupling agent according to the present invention, more preferably, 3 to 50% by weight of the weight of the porous body with respect to the diene-based high molecular weight substance to be adsorbed on the porous body in advance. If the amount is less than 3% by weight, the adhesive strength is insufficient and the performance on ice is not sufficiently improved. On the other hand, if the amount is more than 50% by weight, a large amount of sulfur atoms are released from the A group in the coupling agent molecule. This is because the rubber matrix has a high elastic modulus, the performance on ice is reduced, and the cost is greatly increased, so that it is not economical and cracks are more likely to occur.

The following equation: Or: In the presence of a compound having a silicon or aluminum-bonded hydroxyl group represented by
The porous body and the rubber matrix can be chemically bonded as well as physically bonded through the pores, and the problem of detachment of the porous body can be greatly improved.

Next, examples of the silane coupling agent compounded in the rubber composition in the present invention are as follows. Bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3- Mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane,
3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3- Trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, Trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3
-Triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, etc., and bis (3-triethoxysilylpropyl) tetrasulfide, 3-trimethoxysilylpropylbenzothiazoletetrasulfide, etc. are preferable. Also, the three Ys may not be the same,
For example, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, 3-nitropropyldimethoxymethylsilane, 3-chloropropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N −
Dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropylbenzothiazole tetrasulfide.

Further, a compounding agent or the like usually used in the rubber industry can be appropriately used. When the foaming means is applied to, for example, tread rubber, the foaming ratio can be controlled from the surface layer of the tread to the innermost layer, and a change in performance on ice until complete abrasion can be reduced. Either a foaming method or a high pressure gas mixing method may be used.

When used for tread rubber, the foaming rate is 5
It is preferably about 35%. This is because, when the rubber composition of the present invention is used as a tread rubber for a pneumatic tire, in a state where a large amount of water is melted on the ice surface at around 0 ° C., the micro drainage effect by the pores is increased, and excellent ice and snow are obtained. This is because such closed cells are desirable in order to exhibit performance.

Here, the foaming ratio V _S is expressed by the following equation: V _S = {(ρ _o −ρ _g ) / (ρ ₁ −ρ _g ) −1} × 100 (%) (1) _l is the density of foamed rubber (g / cm ³ ), ρ
_o is the density (g / cm ³ ) of the solid phase portion of the foamed rubber, and ρ _g is the density (g / cm ³ ) of the gas portion in the foamed rubber bubbles.
The foamed rubber is composed of a solid phase portion and a cavity (closed cell) formed by the solid phase portion, that is, a gas portion in the air bubble. Since the density ρ _{g of the} gas part is extremely small, almost close to zero, and extremely small with respect to the density ρ _{1 of the} solid phase part,
Equation (1) is approximately equivalent to the following equation: V _S = {(ρ _o / ρ _l ) −1} × 100 (%) (2)

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
In each of Examples and Comparative Examples, rubber compositions having the contents shown in the following Tables 3 to 6 were prepared, and these rubber compositions were used for a tread (tire size 195 / 65R1).
4) was prepared, and the performance described in the table was measured by the following method. The properties of the various porous bodies in Tables 3 to 6 are shown in Table 1 below, and the types of diene rubber or diene rubber composition adsorbed on the porous bodies are shown in Table 2 below.

The method of previously adsorbing the diene rubber alone (A) or the diene rubber compositions (A) to (E) or the resins (F) and (G) on the surface of the porous body to obtain a composite is as follows. It is as follows. 30 g of a 30% by weight diene rubber (A) is prepared with respect to 100 g of the porous body, and then 30 g of the diene rubber (A) is dissolved in 3 liters of toluene, and 100 g of the porous body is poured therein. After stirring for 1 hour, the toluene was distilled off and further dried under vacuum for 24 hours.
130 g of the desired product was obtained.

Further, the adsorbed components (a) to (e) and (g) are weighed according to the composition table, and are weighed by an OOC Banbury mixer.
The mixture was kneaded for about 3 minutes, kneaded with carbon black, and then kneaded with a vulcanization accelerator and sulfur in a second kneading step to obtain various compounds. Next, a desired diene-based rubber compounded rubber composition for adsorption was weighed with respect to the porous body in the same manner as described above, and the desired product was obtained sequentially.

Resorcinol formalin latex (K)
Is 30 g which is 30% by weight based on 100 g of the porous body.
Prepared, immersed for 1 hour, dried at 70 ° C. for 2 hours,
Dry at 130 ° C for 2 minutes, and further at 220-250 ° C for 80 minutes.
Finish drying treatment was performed for 2 seconds. Other conjugates were similarly prepared.

In addition, raisoncin formalin latex (R
The preparation method of FL) is as follows. Rezoncin 14.9 (parts by weight) Formaldehyde 37% aqueous solution 19.0 Sodium hydroxide 10% aqueous solution 18.2 Vinylpyridine latex ^{* 1} 190.5 Styrene-butadiene copolymer latex ^{* 2} 195.4 Soft water 562.0 1000. 0 * 1: Latex JSR0680 manufactured by Nippon Synthetic Rubber Co., Ltd. * 2: Latex JSR2108 manufactured by Nippon Synthetic Rubber Co., Ltd.

The method of preparing the dip solution having the above mixing ratio is as follows. First, resorcinol is dissolved in 372.5 g of soft water, and then a 10% aqueous solution of sodium hydroxide is added with stirring, and a 37% aqueous solution of formaldehyde is further added. 6 at ℃
After aging for a while, this was designated as solution A. On the other hand, the remaining soft water 1
Latex was added to 89.5 g, and the mixed liquid was used as Liquid B. The above solution A was added to this solution B, and the mixture was further added at 25 ° C.
After aging for a time, a conventional RFL dip solution was prepared.
The RF / L of this dipping solution was 16% by weight, and the solid content was 1%.
8% by weight, and VP / (VP + SBR) is 7.5% by weight
Met.

On- ice braking performance was evaluated on an ice road at an ice temperature of -2 ° C. For the evaluation tires, after traveling straight on the asphalt road of our test course for 200 km, braking was performed at a speed of 20 km / h, and Comparative Examples 1 to 9 were indicated as indexes as controls for the corresponding examples. The larger the value, the better.

Abrasion resistance Comparative examples 1 to 9 after running for 20,000 km were evaluated by running on a general road.
Is shown as an index as a control for the corresponding example. The larger the value, the better.

[0047]

[Table 1]

The porous body types A to I are all JIS-K
6301, C type hardness type (HD-1
02N) is 99. In the above-mentioned porous body, what is necessary is crushed or classified by sieving,
It was readjusted to the desired particle size.

[0049]

[Table 2] * 1 Kneading conditions: Starting from 70 rpm, 70 ° C, 160 ° C
* 3 Kneading conditions: 70 rpm, starting from 70 ° C and 110 ° C
Up to about 1.5 minutes * 3 Syndiotactic-1, manufactured by Nippon Synthetic Rubber Co., Ltd.
2-polybutadiene RB840 * 4 bis (3-triethoxysilylpropyl) -tetrasulfide * 5 dibenzothiazyl disulfide

[0050]

[Table 3]

[0051]

[Table 4]

[0052]

[Table 5]

[0053]

[Table 6]

[0054]

[Table 7]

* 6: Nocrack 6C manufactured by Ouchi Shinko Chemical Co., Ltd. * 7: N-cyclohexyl-2-benzothiazyl-sulfenamide (vulcanization accelerator) * 8: dinitrosopentamethylenetetramine * 9: DPT: urea = 1: 1 (weight ratio)

[0056]

As described above, in the rubber composition of the present invention, a diene rubber or a composite in which a diene rubber composition has been adsorbed in advance is blended on a specific porous material surface. As compared with the case where the porous body is simply compounded into the rubber composition without forming the composite, the braking performance on ice is remarkably improved. Further, when the rubber composition of the present invention containing a specific porous body is used as a tread rubber of a pneumatic tire, a physical bonding force is obtained between the porous body and the rubber matrix, and braking performance on ice and The effect that the wear resistance is improved and the occurrence of cracks can be suppressed can be obtained. Furthermore, when a porous body having a specific chemical group on the surface is used, and when a specific coupling agent is blended, not only the physical bonding force but also the two can be chemically bonded. As a result, the above characteristics are further improved. Furthermore, by making the rubber foamable, the water removing effect due to the unevenness of the closed cells can be added, which is more effective.

Claims (8)

[Claims] 1. A composite made of a material having a JIS-C type hardness of 75 or more and having a porous body having an average diameter of 5 to 3000 μm, on which an adsorption component including a diene-based high molecular weight material is previously adsorbed, A rubber composition comprising 3 to 30 parts by weight based on 100 parts by weight of all diene rubber components (including the diene rubber in the adsorption component). 2. An average pore diameter of the surface of the porous body is 40 to 40.
1000 ° and BET nitrogen adsorption specific surface area is 10
The rubber composition of claim 1 wherein the 800 m ² / g. 3. The adsorption component of the composite is at least one of a diene rubber, a rubber composition containing a diene rubber, a resorcinol formalin latex, a syn-1,2-polybutadiene resin and a carbon-containing composition thereof. The rubber composition according to claim 1 or 2, wherein 4. The rubber composition according to claim 1, wherein the porous body has a silicon-bonded hydroxyl group (Si-OH) and / or an aluminum-bonded hydroxyl group (Al-OH) on the surface. 5. In the adsorption component, a general formula: Y ₃ —Si—C _n H _2n A (where Y is an alkyl group having 1 to 4 carbon atoms, an alkoxyl group or a chlorine atom, and three Y's are the same) But it can be different,
n represents an integer of 1 to 6, A is _-S m _C n _H 2n Si-
Y is ₃ group and -S m _Z group selected from the group consisting of groups, wherein Z is M is an integer of 1 to 6, and Y and n are as described above. The rubber composition according to any one of claims 1 to 4, further comprising a coupling agent represented by the formula: 6. The rubber composition according to claim 1, wherein carbon black and / or a vulcanization accelerator are blended in the adsorption component. 7. The rubber composition according to claim 1, which has foamability. 8. A pneumatic tire, wherein the rubber composition according to any one of claims 1 to 6 is used as a tread rubber.