JP2002080638A - Rubber composition for tire tread - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a tire tread which has improved wet skid performance without lowering abrasion resistance and rolling resistance. SOLUTION: The rubber composition for a tire tread comprises (A) 100 parts by weight of a rubber component consisting of 30-100% by weight of a plastic copolymer of an aromatic vinyl with a conjugative diene and 0-70% by weight of the other elastomer, (B) 5-30 parts by weight of clay having an average particle size of 10 μm or less, and (C) 5-100 parts by weight of carbon black having a nitrogen adsorption specific surface area of 70-300 m2/g, wherein the plastic copolymer has a glass transition point of -70-0 deg.C, a styrene unit content of 15-60% by weight and a 1,2-diene unit content of 15-70% by weight and the clay has a rate of 5-30% by weight relative to the total fillers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a tire tread, and more particularly to a rubber composition for a tire tread without deteriorating abrasion resistance and rolling resistance characteristics, such as braking performance and steering stability on a wet road surface (wet skid). (Performance) is improved.

[0002]

2. Description of the Related Art In recent years, characteristics required for automobile tires are various, such as driving stability, abrasion resistance, and riding comfort, in addition to low fuel consumption. Various measures have been devised to improve these performances. For example, in order to improve braking performance and handling stability on wet road surfaces during high-speed driving, it is necessary to increase the grip force with the road surface, increase the block rigidity of the tire tread pattern, and improve the block when cornering. Examples include a method of preventing deformation and improving cornering characteristics, and a method of preventing deformation of a groove formed in a tire tread to smoothly drain water and prevent hydroplaning. Recently, to meet such required characteristics, grip performance on wet road surfaces has been enhanced by blending silica with high styrene SBR.

[0003] However, the rubber composition for a tire tread as described above can enhance the grip force in a low temperature region where the road surface temperature is 15 ° C or less, but can be used on a wet road surface or a semi-wet surface in a high temperature region exceeding 15 ° C. It is said that a (semi-dry) road surface cannot exhibit sufficient grip.
Further, it has been found that the rubber composition containing silica decreases the rigidity of the rubber when the vehicle is repeatedly run, and the grip force is greatly reduced. In addition, in the rubber composition containing silica, if the dispersion of the silica particles in the rubber is insufficient, the Mooney viscosity of the rubber composition increases, and problems such as poor processability such as extrusion occur.

Various proposals have conventionally been made to solve these problems. For example, Japanese Unexamined Patent Publication No.
No. 75 and Japanese Patent Application Laid-Open No. 8-31245,
Japanese Unexamined Patent Publication (Kokai) No. 8-3373 discloses a rubber composition in which calcined clay is blended with a diene rubber, and a rubber composition in which a vulcanized rubber powder comprising a diene rubber and kaolinite is blended with a specific diene rubber. It is disclosed that it is effective in improving grip performance and the like. Also, JP-A-8-59893 and JP-A-8-59
No. 894 discloses SB having a specific styrene content.
A rubber composition in which an inorganic compound powder having a specific composition is blended with R and carbon black is disclosed in JP-A-7-14995.
No. 4 and Japanese Patent Application Laid-Open No. 9-31250 disclose a rubber composition comprising a diene rubber having a 1,2-bond content in a butadiene portion within a specific range, and a clay containing kaolinite as a main component mixed with a diene rubber. An article is disclosed, and it is described that there is a similar effect.

However, at present, there is no rubber composition which maintains low heat build-up without deteriorating workability and abrasion resistance and has excellent wet grip performance.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition for a tire tread which improves wet skid performance without deteriorating abrasion resistance and rolling resistance characteristics.

[0007]

The present invention relates to (A) glass
When the transition temperature is -70 to 0 ° C and the styrene unit amount is 15 to 6
0% by weight and 15-70% by weight of 1,2-diene unit
% Of an aromatic copolymer of aromatic vinyl and a conjugated diene 3
0 to 100% by weight, and an elast other than the elastic copolymer
100 parts by weight of a rubber component consisting of 0 to 70% by weight of
(B) Clays 5 to 30 having an average particle diameter of 10 μm or less
Parts by weight and (C) nitrogen adsorption specific surface area of 70 to 300
m^Two/ G of 5 to 100 parts by weight of carbon black
And the ratio of the clay to all fillers is 5
For tire tread, characterized in that the content is up to 30% by weight.
Rubber composition, 100 parts by weight of the rubber component (A)
(D) the nitrogen adsorption specific surface area is 100 to 300
m^Two/ G of silica 35 to 150 parts by weight, (E) soft for rubber
30 to 200 parts by weight of the agent and 2 to 20 with respect to silica
% By weight of (F) silane coupling agent, silica
And the total amount of carbon black is 45 to 165 parts by weight
The aforementioned rubber composition for a tire tread, the aforementioned silaneca
The coupling agent (F) is represented by the general formula (1): Y_ThreeSi-C_nH_2nA (1) (wherein, Y is an alkyl group or an alkoxy group having 1 to 4 carbon atoms)
Or a chlorine atom, and three Y's are the same or different
N may be an integer of 1 to 6, A may be -S_mC_nH _2n-S
iY_ThreeGroups (m is an integer of 1 to 9, n is the same as described above), nitro
Loxo, mercapto, amino, epoxy, vinyl
Group, chlorine atom, imide group and -S_mZ group (m is 1 to 6
And n and Y are each as described above.
And Z is represented by the following equations (2), (3) and (4).
Is a group selected from the group consisting of
The rubber composition for a tire tread, which is a compound, and
The elastic copolymer is formed of the aromatic vinyl and the conjugated diene.
And the elastic copolymer produced by a solution polymerization method.
And a rubber composition for a tire tread.

[0008]

Embedded image

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber composition for a tire tread of the present invention comprises a rubber component (A), a clay (B) and carbon black (C).

[0010] The rubber component (A) used in the present invention contains an elastic copolymer of aromatic vinyl and a conjugated diene.

[0011] The elastic copolymer contains an aromatic vinyl unit derived from styrene. The amount of styrene unit in the elastic copolymer is preferably 15 to 60% by weight. If the styrene unit amount is less than 15% by weight, sufficient grip performance cannot be obtained, while if it exceeds 60% by weight, the abrasion resistance of the rubber composition is reduced, and the rubber becomes too hard to lower the grip performance. . From the viewpoint of grip performance and abrasion resistance of the rubber composition, the styrene unit amount is more preferably 25 to 60% by weight.

The elastic copolymer contains a 1,2-diene unit derived from a 1,2-bonded conjugated diene. 1,2
The diene unit is from 15 to 70% by weight, more preferably from 18 to 6%;
Preferably it is 5% by weight. If the 1,2-diene unit content is less than 15% by weight, sufficient grip performance cannot be obtained, and if it exceeds 70% by weight, the abrasion resistance of the rubber composition decreases. Examples of the conjugated diene include butadiene and isoprene.

The remainder of the units contained in the elastic copolymer is a 1,4-diene unit derived from a 1,4-bonded conjugated diene (referred to as a 1,4-bonded diene unit). Is preferred.

The glass transition temperature of the elastic copolymer (T
g) is -70 to 0 ° C. When Tg exceeds 0 ° C., the elasticity of the rubber composition is insufficient, and the brittleness resistance decreases in winter and the like. Since the elastic copolymer is a copolymer of aromatic vinyl and a conjugated diene, the lower limit of Tg is -7.
It is difficult to lower the temperature below 0 ° C. Further, Tg is preferably -50 to -10C from the viewpoint of grip performance of the rubber composition.

Specific examples of the elastic copolymer include styrene-butadiene copolymer (SBR), styrene-isoprene copolymer, styrene-isoprene-butadiene copolymer (SIBR), and the like. SBR and SIBR are preferred from the viewpoint of the grip performance of the composition. These elastic copolymers may be used alone,
A combination of more than one species may be used.

As a method for producing the elastic copolymer, there may be mentioned a production method in which the aromatic vinyl and the conjugated diene are copolymerized by a polymerization method such as an emulsion polymerization method or a solution polymerization method. In view of the rolling resistance characteristics and grip performance of the product, a production method by a solution polymerization method is particularly preferable. Solution polymerization method, in a solvent such as hydrocarbons,
The reaction can be carried out using a suitable solution polymerization reagent (such as an organolithium compound).

The rubber component (A) used in the present invention further contains 0 to 70% by weight of an elastomer other than the elastic copolymer.

Examples of the elastomer other than the elastic copolymer include natural rubber, isoprene rubber, butadiene rubber, ethylene-propylene-diene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, and butyl rubber. These may be used alone,
Two or more kinds may be used in combination. Among them, butadiene rubber, isoprene rubber and natural rubber are preferred in terms of abrasion resistance and brittleness resistance.

The proportion of the elastic copolymer in the rubber component (A) is 30 to 100% by weight, preferably 40 to 100%.
% By weight. The proportion of the elastomer other than the elastic copolymer is 0 to 70% by weight, preferably 0 to 60% by weight. The ratio of the elastic copolymer in the rubber component is 3
When it is less than 0% by weight and the proportion of the elastomer other than the elastic copolymer exceeds 70% by weight, it is difficult to achieve both wet skid performance and abrasion resistance of the rubber composition.

The clay (B) used in the present invention is a component used for improving wet skid performance and controlling a decrease in wear resistance.

The average particle diameter of the clay is 10 μm or less. If the average particle diameter exceeds 10 μm, the abrasion resistance decreases, which is not preferable. Furthermore, from the viewpoint of the balance between the wet skid performance improving effect and the wear resistance, the average particle diameter of the clay is preferably 0.1 to 10 μm,
More preferably, it is 0.5 to 10 μm.

The amount of the clay is 5 to 30 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the rubber component (A). When the amount of the clay is less than 5 parts by weight, the effect of improving the wet skid performance is reduced, and when it exceeds 30 parts by weight, the wear resistance of the rubber composition is reduced.

The compounding ratio of the clay to all fillers used in the rubber composition of the present invention is 5 to 30% by weight. Here, the total filler refers to the sum of the clay and other fillers (carbon black (C) and silica (D) described below). 5% by weight of clay
If it is less than 30%, the effect of improving the rolling resistance characteristics and wet skid performance of the rubber composition is small, and if it exceeds 30% by weight, the abrasion resistance is reduced. Rolling resistance characteristics of the rubber composition,
From the viewpoint of the balance between wear resistance and wet skid performance, the compounding ratio of clay is more preferably 10 to 25% by weight.

The carbon black (C) used in the present invention has a nitrogen adsorption specific surface area (N ₂ SA) of 70 to 3
00m ² / g, preferably from 100 to 250 m ² / g. If the N ₂ SA of the carbon black is less than 70 m ² / g, the dispersibility improving effect and the reinforcing effect become small, and
If it exceeds ² / g, the dispersibility decreases, the heat build-up of the rubber composition increases, and the abrasion resistance decreases.

Examples of the carbon black include HA
F, ISAF, SAF, etc., but are not particularly limited.

The compounding amount of carbon black contained in the rubber composition of the present invention is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, based on 100 parts by weight of the rubber component (A). If the compounding amount of carbon black is less than 5 parts by weight, a sufficient reinforcing effect cannot be obtained and the wear resistance of the rubber composition decreases, and if it exceeds 100 parts by weight, the dispersibility decreases and the heat build-up of the rubber composition decreases. Increase.

The rubber composition of the present invention can further contain a predetermined silica (D), a rubber softener (E) and a silane coupling agent (F).

The silica (D) is used for reducing the rolling resistance and reinforcing the rubber component.

The silica has a nitrogen adsorption specific surface area (N ₂
SA) is from 100 to 300 m ² / g, preferably from 130 to 300 m ² / g.
280 m ² / g. N ₂ SA of silica is 100 m ² /
If it is less than g, the reinforcing effect tends to be small, and 300 m ²
If it exceeds / g, the dispersibility tends to decrease and the exothermicity of the rubber composition tends to increase.

Examples of the silica include dry process silica (silicic anhydride) and wet process silica (hydrous silicic acid). These may be used alone or in combination of two or more. Good. Among these, wet-process silica is preferred from the viewpoint of improving the rolling resistance characteristics.

The compounding amount of the silica is as follows.
35 to 150 parts by weight, preferably 4 parts by weight, per 100 parts by weight
0 to 120 parts by weight. If the amount of silica is less than 35 parts by weight, sufficient wet grip performance tends not to be obtained, and if it exceeds 150 parts by weight, workability tends to decrease.

The total amount of the silica and the carbon black (C) is preferably 45 to 165 parts by weight, more preferably 50 to 150 parts by weight, based on 100 parts by weight of the rubber component (A). is there. If the total amount is less than 45 parts by weight, the reinforcing effect such as abrasion resistance tends to be small, and if it exceeds 165 parts by weight, dispersibility is reduced, workability is inferior, and exothermicity of the rubber composition tends to increase. There is.

The rubber softener (E) is used for facilitating the kneading operation of the rubber composition, improving workability, and further improving wet performance such as grip performance.

Examples of the rubber softener include paraffin-based process oil, naphthene-based process oil, aromatic-based process oil, and special process oil. These may be used alone or in combination of two or more. Of these, aromatic process oils and naphthene process oils are preferred from the viewpoint of the grip properties of the rubber composition.

The rubber softener is used in an amount of 30 to 200 parts by weight, preferably 50 to 150 parts by weight, more preferably 50 to 150 parts by weight, per 100 parts by weight of the rubber component (A).
100 parts by weight. If the amount of the rubber softener is less than 30 parts by weight, the effect of using the rubber softener tends not to be sufficiently obtained, and if it exceeds 200 parts by weight, workability tends to decrease.

The silane coupling agent (F) is used to strengthen the bond between the filler and the rubber component and to improve the wear resistance of the rubber composition.

The silane coupling preferably used in the present invention
For example, a compound represented by the general formula (1)
And Y_ThreeSi-C_nH_2nA (1) (wherein Y is an alkyl group having 1 to 4 carbon atoms, alkoxyl
Three Y's may be the same or different in a group or a chlorine atom
N is an integer of 1 to 6, and A is -S_mC_nH _2n-S
iY_ThreeGroup, nitroso group, mercapto group, amino group, epo
Xy group, vinyl group, chlorine atom, imide group and -S_mZ
Groups (where m is an integer from 1 to 6; n and Y are
Z is the same as in the above formula (2),
(3), represented by the formula (4))
It is a group.

Specifically, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-
Triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane,
3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 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 and the like. An example in which three Ys are not the same is a screw (3
-Diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane,
Examples include 3-nitropropyldimethoxymethylsilane, 3-chloropropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, dimethoxymethylsilylpropylbenzothiazole tetrasulfide, and the like. Bis (3-triethoxysilylpropyl) tetrasulfide, 3-trimethoxysilylpropylbenzothiazoletetrasulfide and the like are preferred from the viewpoint of achieving both the effect of adding the coupling agent and the cost.

These silane coupling agents may be used alone or in combination of two or more.

The amount of the silane coupling agent is 1 to the total amount of the clay (B) and the silica (D).
-20% by weight is preferred. The amount of the silane coupling agent is 1% by weight based on the total amount of the clay and the silica.
If the amount is less than the above, the effect of adding the silane coupling agent is not sufficient. If the amount exceeds 20% by weight, the coupling effect cannot be obtained, but the reinforcing property and abrasion resistance are lowered although the cost is increased. In terms of dispersion effect and coupling effect,
It is desirable that the blending amount of the silane coupling agent is 2 to 15% by weight.

The rubber composition of the present invention contains the rubber component (A), clay (B), carbon black (C), silica (D), softener for rubber (E), silane coupling agent In addition to (F), if necessary, compounding agents used in the ordinary rubber industry, such as an antioxidant, a vulcanizing agent, a vulcanization accelerator, and a vulcanization accelerator may be appropriately compounded.

[0042]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 4 and Comparative Examples 1 to 8 According to the compounding recipes shown in Tables 1 and 2 below, kneading and compounding were performed to obtain various test rubber compositions. These compounds were press-vulcanized at 170 ° C. for 20 minutes to obtain vulcanized products, which were tested for the following properties.

<Description of Various Chemicals> SBR-A: TUFDENE-3 manufactured by Asahi Kasei Corporation
330 (SBR, oil (softening agent for rubber) content: 37.5 parts by weight based on 100 parts by weight of rubber component, glass transition temperature: -20 ° C, styrene unit amount: 30% by weight, 1,2-
Butadiene unit amount: 30% by weight, polymerization method: solution polymerization method) SBR-B: TUFDENE-1 manufactured by Asahi Kasei Kogyo Co., Ltd.
530 (SBR, oil (softening agent for rubber) content: 37.5 parts by weight based on 100 parts by weight of rubber component, glass transition temperature: -48 ° C, styrene unit amount: 18% by weight, 1,2-
(Butadiene unit amount: 13% by weight, polymerization method: solution polymerization method) BR150B: UBPOL BR1 manufactured by Ube Industries, Ltd.
50B (butadiene rubber) Clay: South Eastern Crown Clay (particle size
2 μm or less: 86%, 5 μm or more: 4%) Carbon black: Show Black N220 (N ₂ SA: 125 m ² / g) manufactured by Showa Cabot Co., Ltd. Silica: Ultrasil VN3 (N ₂ manufactured by Tegussa)
SA: 210 m ² / g) Aroma oil: JOMO PROXEL X140 (softening agent for rubber) manufactured by Japan Energy Co., Ltd. Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Degussa Antiaging Agent: Nocrack 6 manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
C (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine) Stearic acid: Stearic acid manufactured by NOF CORPORATION Zinc oxide: Zinc flower No. 1 manufactured by Mitsui Kinzoku Mining Co., Ltd. Sulfur: powder sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator TBBS: Noxeller NS (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) (chemical name: N-tert-butyl-2-)
Benzothiazyl sulfenamide) Vulcanization accelerator DPG: Noxeller D (Ouchi Shinko Chemical Co., Ltd.) (chemical name: N, N'-diphenylguanidine)

<Explanation of Test Method> (Abrasion test) A Lambourn abrasion tester was used at a temperature of 20 ° C.
The Lambourn abrasion amount was measured under the conditions of a slip ratio of 20% and a test time of 5 minutes. The volume loss of each formulation was calculated, and the index of Comparative Example 1 was set to 100 (reference) for Comparative Examples 1-2 and Examples 1-4, and Comparative Example 3 was used for Comparative Examples 3-8.
The index was expressed by the following formula with the index of 100 as the reference (standard). The larger the index, the better the wear resistance. (Abrasion resistance index) = (Volume loss of Comparative Example 1 or Comparative Example 3) / (Volume loss of each formulation) × 100

(Rolling resistance index) Using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho), a temperature of 7
The tan δ of each formulation was measured under the conditions of 0 ° C., an initial strain of 10%, and a dynamic strain of 2%. Comparative Examples 1-2 and Examples 1-4
The index of Comparative Example 1 was set to 100 (reference), and the indexes of Comparative Examples 3 to 8 were set to 100 (reference) by the following formula. The larger the index, the better the rolling resistance characteristics. (Rolling resistance index) = (ta of Comparative Example 1 or Comparative Example 3)
nδ) ÷ (tan δ of each formulation) × 100

(Wet skid test) ASTM E30 using a portable skid tester made by Stanley
The wet skid resistance was measured according to the method of 3-83. For Comparative Examples 1 and 2 and Examples 1 to 4, the index of Comparative Example 1 was set to 100 (reference), and for Comparative Examples 3 to 8, the index of Comparative Example 3 was set to 100 (reference) and indicated by the following formula. . The higher the index, the better the wet skid performance. (Wet skid index) = (Wet skid resistance of each formulation) ÷ (Wet skid resistance of Comparative Example 1 or Comparative Example 3) × 100 The results are shown in Tables 1 and 2.

[0048]

[Table 1]

[0049]

[Table 2]

In contrast to Comparative Example 1 in which carbon black and clay were not blended at all, Examples 1 to 4 in which carbon black and clay were blended in specific amounts exhibited wet skid performance without lowering abrasion resistance and rolling resistance characteristics. Could be improved. In Comparative Example 4 in which only carbon black was added and no clay was added, the abrasion resistance could be improved, but the rolling resistance characteristics and wet skid performance were significantly reduced.

Comparative Examples 3 to 8 are examples using SBR having a 1,2-butadiene unit content of 13% by weight. Comparative Example 4 in which a specific amount of carbon black and clay were blended with respect to Comparative Example 3 in which carbon black and clay were not blended
In No. 8, the wet skid resistance could not be improved.

[0052]

According to the rubber composition for a tire tread of the present invention, the wet skid performance can be improved without lowering the abrasion resistance and the rolling resistance characteristics.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 3/34 C08K 3/34 3/36 3/36 5/541 C08L 91/00 C08L 91/00 (C08L 9/06 // (C08L 9/06 21:00) 21:00) C08K 5/54 (72) Inventor Yasuhisa Minagawa 3-6-9, Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo Sumitomo Rubber Industries Co., Ltd. (72) Invention Person Naohiko Kikuchi 3-6-9, Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo F-term in Sumitomo Rubber Industries Co., Ltd. GN01 4J011 AA05 BA03 BB01 DA04 HA03 HB22 4J100 AB02P AS02Q AS03Q CA04 CA15 CA16 DA25 FA19 JA29

Claims (4)

[Claims] (A) a glass transition temperature of -70 to 0 ° C.
The styrene unit content is 15 to 60% by weight and 1,2-
100% by weight of a rubber component consisting of 30 to 100% by weight of an elastic copolymer of aromatic vinyl and conjugated diene having a diene unit amount of 15 to 70% by weight and 0 to 70% by weight of an elastomer other than the elastic copolymer Parts, (B) the average particle diameter is 10
5 to 30 parts by weight of clay having a particle size of not more than 5 μm or less, and (C) 5 to 100 parts by weight of carbon black having a nitrogen adsorption specific surface area of 70 to 300 m ² / g, and a ratio of the clay to all fillers is 5 to 5 parts by weight. 30% by weight of a rubber composition for a tire tread. 2. The rubber component (A) has a nitrogen adsorption specific surface area of 100 to 30 parts by weight based on 100 parts by weight of the rubber component (A).
35-150 parts by weight of 0 m ² / g silica, (E) 30-200 parts by weight of a rubber softener and 2-2 with respect to silica.
The rubber composition for a tire tread according to claim 1, wherein the rubber composition contains 0% by weight of (F) a silane coupling agent, and the total amount of silica and carbon black is 45 to 165 parts by weight. 3. The method according to claim 1, wherein the silane coupling agent (F) is
General formula (1): Y_ThreeSi-C_nH_2nA (1) (wherein, Y is an alkyl group or an alkoxy group having 1 to 4 carbon atoms)
Or a chlorine atom, and three Y's are the same or different
N may be an integer of 1 to 6, A may be -S_mC_nH _2n-S
iY_ThreeGroups (m is an integer of 1 to 9, n is the same as described above), nitro
Loxo, mercapto, amino, epoxy, vinyl
Group, chlorine atom, imide group and -S_mZ group (m is 1 to 6
And n and Y are each as described above.
And Z is represented by the following equations (2), (3) and (4).
Is a group selected from the group consisting of
The rubber composition for a tire tread according to claim 2, which is a compound.
object. Embedded image 4. The rubber composition for a tire tread according to claim 1, wherein the elastic copolymer is an elastic copolymer produced by a solution polymerization method of the aromatic vinyl and the conjugated diene.