JP3434353B2 - Rubber composition for large tire tread - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-load, low-heat-resistant (high rebound resilience) which is mounted on a large vehicle such as a truck or a bus. The present invention relates to a rubber composition for a large tire tread effective for a fuel-efficient tire. 2. Description of the Related Art There are various types of carbon black for rubber reinforcement depending on the characteristics of the carbon black, and the characteristics of these types are the main factors that determine various properties of a compounded rubber composition. For this reason, in the case of compounding with rubber, a means for selecting and using carbon black having a variety characteristic suitable for the purpose of the member is usually used. In recent years, fuel-efficient tires have been actively developed in order to meet the social demands for resource and energy savings. A rubber composition having low heat build-up and high rebound resilience in which black is blended with a rubber component in a relatively small amount is considered to be effective. However, a rubber composition containing carbon black having a large particle diameter and a small specific surface area is effective for improving the fuel efficiency, but the surface properties such as braking performance on a wet road surface and wear resistance are deteriorated. Inevitable. Therefore, if high wear resistance and low heat build-up (high rebound resilience) can be simultaneously imparted to a compounded rubber using carbon black having a small particle diameter (high specific area), a tire tread intended for low fuel consumption can be provided. It becomes ideal as a rubber member for use. [0004] The applicant of the present invention has determined that the properties of the carbon black to be blended with the rubber properties which are in a trade-off relationship as described above,
In particular, research has been systematically continued to achieve compatibility by adding more microselective characteristics in addition to the basic characteristics such as particle diameter, specific surface area, and structure, and the following development proposals have already been made. (1) Belongs to a hard system region having a BET specific surface area (N ₂ SA) of 60 m ² / g or more, and Dst mode diameter ≧ 4.35 × [electron microscope particle diameter (dn)] + 26.8, ΔDst ≧ 0.6118 × Dst mode Diameter +30.
6. Carbon black for highly elastic rubbers having selective properties of compressed DBP oil absorption ≧ 112 ml / 100 g and capable of simultaneously imparting high reinforcing performance and high resilience to compounded rubber (Japanese Patent Laid-Open No. 59-184231) ). (2) It belongs to the hard type area where the nitrogen adsorption specific surface area (N ₂ SA) is 60 m ² / g or more and the DBP oil absorption is 108 ml / 100 g or more, and the true specific gravity ≦ −0.0006 (N ₂ SA) +1.8379, coloring power (%) ≧ 0.6979
(N ₂ SA) −0.4278 (DBP) +203.3, Aggregate distribution width (ΔDst)
≧ 0.6118 (Dst mode diameter) + Rubber composition having high abrasion resistance and high rebound resilience obtained by blending furnace carbon black having selective properties of +30.6 in a ratio of 25 to 250 parts by weight with respect to 100 parts by weight of the rubber component. (JP-A-59-140241). (3) The nitrogen adsorption specific surface area (N ₂ SA) belongs to a hard system region of 100 to 200 m ² / g, and [T = ΔDst ⁵⁰ × ΔDst ⁷⁵ ×
R] Aggregate size distribution index (T) defined by equation
Is [4100-18.1 (N ₂ SA) <T <7700-25.5 (N ₂ SA)] (ΔDst ⁵⁰ is the half width (nm) of aggregate Stokes mode diameter distribution by centrifugal sedimentation method, ΔDst ⁷⁵ Is the 3/4 value width (nm) of the aggregate Stokes mode diameter distribution, and R is the maximum absorbance of the aggregate Stokes mode diameter distribution.
A rubber composition suitable for a large tire tread compounded in a proportion of 100 parts by weight (JP-A-63-112638). (4) The Stokes mode diameter distribution of aggregates having a nitrogen adsorption specific surface area (N ₂ SA) in the range of 70 to 185 m ² / g and having two maximum values, where [L (nm) = Dst mode diameter _2- Dst mode diameter ₁ ] formula (Dst mode diameter ₁ is the mode diameter at the first maximum point in the aggregate Stokes mode diameter distribution by centrifugal sedimentation.
(nm), Dst mode diameter ₂ refers to the mode diameter (nm) of the second maximum point in the aggregate Stokes mode diameter. )), The carbon black having an aggregate property range satisfying the expression [20 ≦ L ≦ 110−0.3 (N ₂ SA)] is used in an amount of 35 to 100 parts by weight based on 100 parts by weight of the rubber component. Rubber compositions suitable for use in large tire treads, which are blended in proportions (JP-A-63-179941). (5) The nitrogen adsorption specific surface area (N ₂ SA) belongs to a hard region of 110 to 155 m ² / g, and [D = [DBP (ml / 100 g)] − [24M4DBP
(ml / 100g)]] and [K = [ΔDst /
Dst Stokes mode diameter _{(nm)] × [N 2} SA (m 2 / g) / IA (mg /
g)] ² × [B (%)]], the K value is 1 <D <20,
80 <K <165, [0.667 (N 2 SA) -13.37 <K-1.96D <(N
₂ SA) +10] (where, B is Blacks, the maximum frequency of the Stokes equivalent diameter Dst Stokes mode diameter in the aggregate Stokes diameter distribution by centrifugal sedimentation method, DerutaDst is obtained 50% of the frequency of the maximum frequency in the distribution Rubber composition suitable for large tire treads, in which carbon black satisfying the following two requirements is used. 63-297439). (6) Nitrogen adsorption specific surface area (N ₂ SA) is 60 to 160 m ² / g, DB
Belongs to the hard area with P oil absorption of 90-150ml / 100g,
A carbon black for tire treads having selective properties having an aggregate void volume Vp (ml / g) which is equal to or greater than the calculated value of the formula [0.00976 × DBP oil absorption−0.0358] (JP-A-2-32136). [0005] However, material requirements for fuel-efficient tires are becoming more and more severe.
At present, it is difficult for the carbon black and rubber composition according to the prior application to meet recent performance requirements. [0006] The present inventor has found that in a subsequent development study under such a background, the nitrogen adsorption specific surface area (N ₂ SA) is 135.
In the range of ~150m ² / g, a furnace carbon black having a hard system region CTAB adsorption specific surface area and compression DBP oil absorption amount is in the predetermined range, the half-value width (ΔDst) Stokes mode diameter of the Stokes diameter of the aggregates
(Dst), the half-width (ΔDp) of the pore diameter distribution between aggregate particles is in the range of the constant relational expression value. It has been clarified that a rubber composition containing carbon black within the range can provide rubber properties suitable as tread members for large tires such as buses and trucks. The present invention has been developed on the basis of the above facts, and has as its object to provide a high level of wear resistance suitable for fuel-efficient tires for large vehicles such as buses and trucks. Another object of the present invention is to provide a rubber composition for a large tire tread having low heat build-up (high resilience). [0008] In order to achieve the above object, a rubber composition for a large tire tread according to the present invention is provided.
Furnace carbon black having the following selective properties (1) to (5) was added to 35 to 10 parts by weight based on 100 parts by weight of the rubber component.
It is characterized in that it is blended at a ratio of 0 parts by weight. (1) Nitrogen adsorption specific surface area (N ₂ SA): 135 to 150 m ² / g (2) CTAB adsorption specific surface area: 130 to 140 m ² / g (3) Compressed DBP oil absorption: 85 to 95 ml / 100 g (4) Dst 0.519 × Dst + 8.0 ≦ ΔDst ≦ 0.519 × Dst + 32.6 (5) Relationship between Dp mode diameter and ΔDp; 0.776 × Dp + 1.5 ≦ ΔDp ≦ 0.776 × Dp + 40.5 Values obtained by the following measurement methods are used for the respective characteristics of the carbon black according to the constitution. Nitrogen adsorption specific surface area (hereinafter referred to as “N ₂ SA”); AST
MD3037-88 “Standard Test Method for Car
bon Black-Surf-ace Area by Nitrogen Absorption ”Me
It depends on thodB. The measured value of IRB # 6 by this method is 7
6 m ² / g. CTAB adsorption specific surface area (hereinafter referred to as “CTAB”); A
STM D3765-89 “Standard Test Method for
Carbon Black-CTAB (Cetyltrimethyl ammonium bromid
e) According to "Surface Area". Compressed DBP oil absorption (hereinafter referred to as "24M4DBP"); AS
TM D3493-91 "Standard Test Method for C
arbon Black- Dibutyl Phthalate Absorption Number of
Compressed Sample ”. Dst mode diameter (hereinafter referred to as“ Dst ”) and ΔDst; a carbon black sample dried according to JIS K6221 (1982) 5“ How to prepare a dry sample ”containing a small amount of surfactant A dispersion with a carbon black concentration of 50 mg / l was prepared by mixing with a volume% aqueous ethanol solution,
This is sufficiently dispersed with an ultrasonic wave to obtain a sample. 8 disk centrifuges (Joyes Lobel, UK)
Spin speed (2 at 25 ° C)
10% by weight of an aqueous glycerin solution) and 1 ml of a buffer solution (a 20% by volume aqueous ethanol solution at a temperature of 25 ° C.).
Inject. Then, 0.5 ml of the carbon black dispersion at a temperature of 25 ° C. was added with a syringe, and then centrifugal sedimentation was started. At the same time, the recorder was operated to obtain the distribution curve shown in FIG. The vertical axis represents the absorbance at a specific point that has changed with the centrifugal sedimentation of carbon black. Each time T is read from this distribution curve and substituted into the following equation (Equation 1) to calculate the Stokes equivalent diameter corresponding to each time. [0011] In Equation 1, η is the viscosity of the spin liquid (0.935
cp), N is the disk rotation speed (8000 rpm), r ₁ is the radius of the carbon black dispersion injection point (4.56 cm), r ₂ is the radius to the absorbance measurement point (4.82 cm), ρ _CB is the density of carbon black ( g / cm ³ ), ρ ₁ is the density of the spin solution (1.00178 g / cm ^3
3 ). The Stokes equivalent diameter of the maximum frequency in the Stokes equivalent diameter and absorbance distribution curve (FIG. 2) obtained in this manner is defined as Dst (nm), and two points, large and small, at which 50% of the maximum frequency can be obtained. The difference (half-width) of the Stokes equivalent diameter of the above is ΔDst. ASTM D by this measurement method
Dst of -24 Standard Reference Black C-3 (N234) is 80 nm, and ΔDst is 60 nm. Dp mode diameter (hereinafter referred to as “Dp”) and ΔDp; after drying in accordance with JIS K6221 (1982) 5 “How to prepare a dry sample”, a precisely weighed carbon black sample is mixed with distilled water to obtain carbon. A paste having a black concentration of 0.250 g / cm ³ is prepared and sufficiently dispersed by ultrasonic waves. Within 10 minutes after the ultrasonic dispersion, the distribution measurement of the pores between the aggregates is started using a differential scanning calorimeter (DSC30 manufactured by DSC Mettler). In this case, the amount of the collected paste is in the range of about 3 to 5 mg. After sealing in a sample container made of aluminum, the mass of the paste is confirmed, and the paste is set in the DSC device. Next, measurement is performed in the next step. Cool rapidly from room temperature to -80 ° C. Heat from -80 ° C to -5 ° C at a rate of 10 ° C / min. After heating from -5 ° C to -0.1 ° C at a rate of 1 ° C / min., It is kept at -0.1 ° C (a temperature lower than the freezing point of distilled water by 0.1 ° C) for 10 minutes. Cool gradually from -0.1 ° C to -8 ° C at a rate of 0.1 ° C / min. And record the compensation energy. Then, the height (y) of the peak at each temperature (in increments of 0.1 ° C.) is read from the compensation energy chart obtained in step (2), and the pore diameter (Dp) between the aggregate grains is obtained from the following equations (1) and (2). ) And pore size distribution (δV / δDp). These equations were derived by Brun et al.
ta, 21 (1977) 59-88 “A NEW METHOD FORTHE SIMULTANEO
US DETERMINATION OF THE SIZE AND THE SHAPE OF PORE
S: THETHERMOPOROMETRY ”. Dp = (135.34 / ΔT) +1.14 (1) δV / δDp = K · (ΔT) ² / (Wa × y) (2) (1) and (1) In the equation (2), ΔT is the freezing point drop width of distilled water, Wa is the freezing heat of distilled water, and K is a factor taking into account the sensitivity of the DSC device and the mass of the sample. Is the maximum frequency pore diameter at
Let p be the difference between the pore diameters of the two large and small points at which 50% of the maximum frequency is obtained, ΔDp. The furnace carbon black used in the present invention is provided with two generation units each comprising a combustion chamber in which a combustion burner and a feed oil injection nozzle are mounted on a furnace head and a pyrolysis conduit connected to the combustion chamber. Using a Y-shaped oil furnace with the pyrolysis conduits converging and converging into the cylindrical main reaction zone, the intermediate flow of carbon black intermediate product gas generated in another generation system is simultaneously introduced into the main reaction zone at high speed to simultaneously It is manufactured by a method of colliding (JP-A-59-49267).
By controlling conditions such as the supply amount of fuel oil and air and the addition amount of oxygen gas, carbon black having the characteristic range specified in the present invention can be obtained. A high level of abrasion resistance and low heat build-up (high resilience) by blending the above furnace carbon black.
The natural rubber, styrene butadiene rubber, polybutadiene rubber, isoprene rubber, butyl rubber, chloroprene rubber, acrylonitrile-butadiene rubber, ethylene propylene rubber, and other various rubbers that can be reinforced with carbon black And mixed rubber. The compounding ratio of carbon black is 35 to 100 parts by weight with respect to 100 parts by weight of the rubber component, and together with commonly used components such as a vulcanizing agent, a vulcanization accelerator, an antioxidant, a vulcanization aid, a softener, and a plasticizer. The rubber composition for a large tire tread of the present invention is obtained by kneading. In the characteristic items of the furnace carbon black specified in the present invention, N ₂ SA is 135 to 150 m ² / g,
TAB is 130-140 m ² / g and 24M4DBP is 85-
The range of 95 ml / 100 g is a prerequisite for imparting high abrasion resistance and moderately low heat generation to the compounded rubber and imparting excellent workability. Nitrogen adsorption specific surface area and CT
If AB is less than the lower limit, sufficient wear resistance cannot be obtained, while if it exceeds the upper limit of the range, heat buildup increases,
A tread member for a fuel-efficient tire cannot be obtained. Similarly, for 24M4DBP, if it is outside the above range, the abrasion resistance of the compounded rubber will be insufficient, and if it exceeds the above range, the viscosity of the compounded rubber compound will increase and the processability will decrease. Dst and ΔDst are colloidal characteristics related to the size and distribution of the carbon black aggregate. Among them, ΔDst is an index indicating the distribution of the Stokes equivalent diameter of the aggregate.If the distribution width is wide, the reinforcing property such as the wear resistance of the compounded rubber decreases, and if the distribution width is narrow, the rebound resilience decreases. A product with low heat generation cannot be obtained. According to the study by the inventor, it has been confirmed that there is a certain correlation between ΔDst and Dst, and the hard carbon black on the market generally has a relationship of [ΔDst = 0.519 × Dst + 16.6]. In the furnace carbon black of the present invention, ΔDst is [0.519 × D
st + 8.0 ≦ ΔDst ≦ 0.519 × Dst + 32.6] It is an important characteristic item to satisfy the range of the expression, and ΔDst is [0.519 × Dst
+32.6], the abrasion resistance of the compounded rubber decreases when the distribution width becomes relatively large, and the rebound resilience decreases when the distribution width becomes less than [0.519 × Dst + 8.0].
Exothermicity increases. Dp and ΔDp are the colloidal properties related to the morphology of the carbon black aggregate, and the voids and pores between the aggregate particles in the aggregate structure of the aggregate, which is the aggregate of carbon black particles, ie, the aggregates It is an index indicating the size of pores between grains and the distribution thereof. According to the study of the inventors, there is a certain correlation between Dp and ΔDp in the pores between the aggregate grains, and ΔDp of the hard carbon black on the market is approximately [0.776 × Dp−16.4] ± 14. is there. [0.776 × Dp + 1.5 ≦ specified in the present invention]
The range of ΔDp that satisfies the equation ΔDp ≦ 0.776 × Dp + 40.5] is characterized by the fact that the distribution width of intergranular pores is wide in relation to Dp, but ΔDp is [0.776 × Dp + 1.
5] below this value, the suppression of exothermicity becomes insufficient, while
If the value exceeds [0.776 × Dp + 40.5], the wear resistance deteriorates. The rubber composition according to the present invention has a high level of abrasion resistance and low heat generation required for a fuel-efficient large tire tread by comprehensively utilizing the above characteristics of the furnace carbon black to be blended with the rubber component. Properties (high rebound resilience) can be simultaneously imparted in a well-balanced manner. Therefore, it is an essential requirement that the furnace carbon black having all the specified characteristic items be blended with the rubber component. EXAMPLES Examples of the present invention will be specifically described below in comparison with comparative examples. Examples 1-5, Comparative Examples 1-5, Reference Examples 1
3. Combustion chamber with a combustion burner and feed oil injection nozzle coaxially mounted on the head via a wind box (inner diameter 450 mm
, 800 mm in length, of which 200 mm conical part) and a pyrolysis conduit (65 mm in diameter, 500 mm in length)
150mm inner diameter, 2000mm long rear wide section and 9 inner diameter
A convergent connection is made at an angle of 60 ° to the front of the main reaction zone having a 5 mm long, 700 mm long front-stage narrow-diameter section, and a ring member having an aperture ratio of 0.65 is attached to the main reaction zone 50 mm downstream of the convergent connection point. An oil furnace having a Y-shaped structure with an intermediary was installed. For feedstock, specific gravity (15/4 ℃)
1.073, viscosity (engler 40/20 ° C.) 2.10, aromatic hydrocarbon oil having a toluene insoluble content of 0.03%, and correlation coefficient (BMCI) 140, and specific gravity (15/4 ° C)
0.903, viscosity (Cst / 50 ° C.) 16.1, residual carbon content 5.4
%, A hydrocarbon oil having a flash point of 96 ° C. was used. Using the above-mentioned reaction furnace, feed oil and fuel oil, the production conditions such as feed oil supply amount, fuel oil amount, air supply amount, oxygen gas addition amount, etc. in each generation line are varied to obtain 1
Zero types (Examples 1 to 5, Comparative Examples 1 to 5) of furnace carbon blacks were produced. Tables 1 to 3 show the conditions for forming carbon black and the characteristics of the obtained carbon black in association with each other. Table 4 shows the characteristics of commercially available hard carbon black varieties suitable for large tire treads as Reference Examples 1 to 3. Reference Example 1 was manufactured by Tokai Carbon Co., Ltd., "Seast 6" (N220). Reference Example 2 was manufactured by Tokai Carbon Co., Ltd., "Seast 9" (N110), Reference Example 3.
"SEIST 9H" manufactured by Tokai Carbon Co., Ltd. [Table 1] [Table 2] [Table 3] [Table 4] Next, these carbon black samples were blended into natural rubber according to the blending ratios shown in Table 5. [Table 5] Each rubber composition obtained by vulcanizing the composition of Table 5 at a temperature of 145 ° C. for 40 minutes was subjected to various rubber tests, and the measured results were shown in Tables 8 to 9 (Reference Examples are Table 11).
It was shown to. The wear resistance and the loss coefficient (tan δ) of each measurement test were determined by the following method, and all other tests were performed according to JIS.
K6301 "Vulcanized rubber physical test method". Abrasion resistance: Measured using a Lambourn abrasion tester (mechanical slip mechanism) under the following conditions. The numerical value of the wear resistance is an index when the value of Reference Example 2 is set to 100, and the larger the index value, the higher the wear resistance. Test piece: thickness 10mm, outer diameter 44mm Emery wheel: GC type, particle size # 80, hardness H Carburundum powder with addition: particle size # 80, addition amount about 9g / mi
n. Relative slip ratio between emery wheel surface and test piece: 24
%, 60% Test piece rotation speed: 535 rpm Test load: 4 kg Loss factor (tan δ): Measured using a Visco Elastic Spectrometer (Iwamoto Seisakusho) under the following conditions. The smaller the numerical value in the display, the lower the exothermic property. Test piece: thickness 2 mm, length 30 mm, width 5 mm Frequency: 50 Hz Dynamic strain rate: 1.2% Temperature: 60 ° C. Comparative Examples 6 to 16 A tangential air supply port and a furnace shaft on the furnace head. A first-stage narrow-diameter reaction zone (200 mm in diameter, equipped with a combustion chamber (diameter 800 mm, length 800 mm) having a directionally mounted combustion burner and a feed oil injection nozzle coaxially connected to the combustion chamber and penetrating the furnace wall; Length 500m
m), an oil furnace having a second-stage narrow-diameter reaction zone (diameter 160 mm, length 700 mm) and a wide-diameter reaction chamber (diameter 400 mm) sequentially installed. Feedstock was supplied separately from feedstock injection nozzles installed through the furnace walls of the first-stage narrow-diameter reaction zone and the second-stage narrow-diameter reaction zone. The compositions of the feedstock oil and fuel oil were the same as in the example, and the furnace carbon black was produced by varying the feedstock supply amount, fuel oil amount, air supply amount, oxygen gas addition amount, etc. of the first and second stages. Manufactured. Tables 6 and 7 show the characteristics of the obtained carbon black in comparison with the production conditions.
Table 9 shows the physical properties of rubber compositions obtained by blending these carbon blacks with natural rubber under the same conditions as in the examples.
It was also attached to. [Table 6] [Table 7] [Table 8] [Table 9] [Table 10] [Table 11] FIG. 3 is a graph showing the relationship between the abrasion resistance (24% slip) and the loss factor (tan δ) prepared based on the measurement results in Tables 9 to 11.
FIG. 4 shows the relationship between the wear resistance (24% slip) and the rebound resilience. From these scatter diagrams, in FIG. 3, the rubber composition of the example is dispersed in the lower right direction (arrow) as compared with the comparative example and the reference example, and relatively good wear resistance and low heat generation are imparted. You can see that. Similarly, in FIG. 4, the examples are dispersed in the upper right direction (arrows), and it is recognized that the examples have both wear resistance and high rebound resilience. Individually, as is apparent from the consideration of Tables 8 to 11, the rubber compositions of the Examples satisfying the carbon black characteristics requirements specified in the present invention are compared with Comparative Examples having the same level of specific surface area. As a result, the wear resistance is improved, and at the same time, the loss coefficient (tan δ) decreases and the rebound resilience increases. On the other hand, in Comparative Example 1 in which N ₂ SA and CTAB are lower than the specific ranges, sufficient abrasion resistance is not obtained. On the other hand, in Comparative Example 5, in which the specific surface area is higher than the specific range, the loss coefficient is high and the heat buildup is low. Is growing. In Comparative Example 2 in which 24M4DBP was lower than the specific range, the abrasion resistance of 60% slip was greatly reduced,
Conversely, in Comparative Example 3 exceeding the specific range, the workability is lowered, and the heat build-up is higher than in Example 3 having the same specific surface area. Comparative Examples 6, 7, 1 where ΔDst deviates from the relational expression to the higher side
Comparative Example 4, which had inferior abrasion resistance as compared with Example 3 having the same level of particle diameter, and deviated to a lower level, had equivalent N
₂ Exothermicity and rebound resilience are lower than in Example 4 with SA level. Comparative Examples 10, 11, where ΔDp deviates from the relational expression low
Comparative Example 1 was inferior in both heat build-up and rebound resilience to Examples 3 and 4 having the same level of specific surface area, and conversely deviated to a high level.
2, 13, and 14 have reduced wear resistance. As described above, according to the present invention, by selectively controlling the micro-colloidal characteristics of the furnace carbon black different from the prior art, relatively excellent wear resistance and low heat build-up can be obtained. It is possible to provide a rubber composition having high rebound resilience at the same time in a well-balanced manner. Therefore, the present invention can be applied to a large tire tread member such as a truck and a bus to achieve effective fuel saving.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a distribution curve showing changes in absorbance due to centrifugal sedimentation of carbon black and the elapsed time from the addition of the carbon black dispersion during the measurement of Dst. FIG. 2 is a distribution curve showing the relationship between Dst and absorbance obtained when measuring Dst. FIG. 3 shows the abrasion resistance (24%) in Examples, Comparative Examples and Reference Examples.
FIG. 3 is a dispersion diagram showing a relationship between slip) and a loss coefficient (tan δ). FIG. 4 shows the abrasion resistance (24%) in Examples, Comparative Examples and Reference Examples.
FIG. 4 is a dispersion diagram showing a relationship between slip) and rebound resilience.

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L ^7/ 00-21/02

Claims (1)

(57) [Claims 1] A furnace carbon black having the following selective properties (1) to (5) is blended in a ratio of 35 to 100 parts by weight with respect to 100 parts by weight of a rubber component. A rubber composition for a large tire tread, comprising: (1) Nitrogen adsorption specific surface area (N ₂ SA): 135 to 150 m ² / g (2) CTAB adsorption specific surface area: 130 to 140 m ² / g (3) Compressed DBP oil absorption: 85 to 95 ml / 100 g (4) Dst 0.519 × Dst + 8.0 ≦ ΔDst ≦ 0.519 × Dst + 32.6 (5) Relationship between Dp mode diameter and ΔDp; 0.776 × Dp + 1.5 ≦ ΔDp ≦ 0.776 × Dp + 40.5