KR100713705B1 - Tire tread rubber composition with improved wet traction - Google Patents

Abstract

The present invention relates to a rubber tread rubber composition having improved wet traction performance on wet roads, and more specifically, a solution-polymerized styrene-butadiene rubber having a styrene content of 20 to 50% by weight and a vinyl content of 20 to 50% by weight of butadiene. With respect to 100 parts by weight of the raw material rubber including 60 to 100 parts by weight and 0 to 40 parts by weight of butadiene rubber, carbon black alone having a BET value of 100 to 180 m ² / g and a DBP adsorption amount of 80 to 160 ml / 100 g, or the Hydrophilic composition consisting of 30 to 100 parts by weight, 30 to 70% by weight of clay and 30 to 70% by weight of polymer, using carbon black and precipitated silica having a BET value of 120 to 200 m ² / g and a DBP adsorption amount of 200 to 300 ml / 100 g. By including 5-30 parts by weight of the inorganic blend, the wear resistance relates to a rubber composition for tire treads with improved wet traction performance while showing an equivalent level or more.

Solution polymerization-styrene butadiene rubber, wet traction

Description

TIRE TREAD RUBBER COMPOSITION WITH IMPROVED WET TRACTION}

The present invention relates to a rubber composition for tire treads with improved wet traction performance on wet roads. It relates to a rubber composition for tread.

As the high speed driving and the light weight are increased due to the increase of the automobile performance according to the development of the automobile industry, the demand for steering performance is increasing day by day. Especially, wet traction performance is important because the braking distance increases on wet roads.

Conventional techniques for reinforcing the tire's wet traction performance on wet roads include styrene-butadiene rubber with high styrene content and rubbers with high vinyl content in the structure of butadiene in solution-polymerized styrene-butadiene rubber, respectively, or It was used in combination. However, all of these methods have a problem in that the production cost of the tread rubber composition increases in productivity due to a complicated manufacturing process and the production cost of the rubber composition increases due to expensive materials.

In addition, there is a method of increasing the effective reaction surface area of the inorganic fillers added to the tire tread rubber composition, but it is difficult to directly control the main chain of each of the raw material rubber, there was a limit to improve the performance of the compound.

An object of the present invention is to solve the problems of the prior art as described above, by adding a blend of clay and polymer, which is a micron level material having high adsorption and swellability by water as a water swellable material, to a tread rubber composition, It is to provide a rubber composition for tire treads with improved wet traction performance without affecting rolling resistance, processability and the like.

The tire tread rubber composition according to the present invention is a raw material consisting of 60 to 100 parts by weight of a solution-polymerized styrene butadiene rubber having a styrene content of 20 to 50% by weight, a vinyl content of 20 to 50% by weight of butadiene, and 0 to 40 parts by weight of butadiene rubber. With respect to 100 parts by weight of rubber, carbon black alone or in combination with carbon black and precipitated silica, 30 to 100 parts by weight and 5 to 30 parts by weight of a hydrophilic inorganic blend composed of 30 to 70% by weight of clay and 30 to 70% by weight of polymer Characterized in that.

The solution-polymerized styrene-butadiene rubber (S-SBR) used in the present invention has a styrene content of 20 to 50% by weight, and preferably a vinyl content of 20 to 50% by weight in butadiene. When the styrene content is less than 20% by weight, the traction performance tends to deteriorate. When the styrene content is more than 50% by weight, the traction performance tends to be excellent while the wear performance and the rolling resistance tend to decrease. Further, when the vinyl content in the butadiene is less than 20% by weight, the rolling resistance performance is lowered. When the vinyl content in the butadiene is more than 50% by weight, the rolling resistance performance is excellent, but the wear performance tends to be lowered.

In the present invention, it is preferable to use a mixture of 60 to 100 parts by weight and 0 to 40 parts by weight of butadiene rubber (BR) in a solution-polymerized styrene butadiene rubber in which the styrene content and the butadiene vinyl content in the above ranges are used as raw rubbers. If the content is out of the above range, the wear performance or wet traction performance tends to decrease.

In the tire tread compositions of the present invention, carbon black is the BET value of 100 ~ 180m ² / g, DBP absorption together amount is preferably from 80 ~ 160ml / 100g, if the BET value is less than 100m ² / g ability reinforcing properties and abrasion resistance It is not preferable because it is lowered, and if it exceeds 180 m ² / g, dispersibility problems occur, and it is not preferable.If DBP adsorption amount is less than 80 ml / 100 g, reinforcement is lowered, and if it exceeds 160 ml / 100 g, dispersibility of reinforcing material This lowers and is not preferable.

In the tire tread composition of the present invention, the precipitated silica has a BET value of 120 to 200 m ² / g and a DBP adsorption amount of 200 to 300 ml / 100 g, but when the BET value is less than 120 m ² / g, the reinforcement is lowered. It is not preferable, and if it exceeds 200m ² / g, dispersibility problem is raised, and it is not preferable.If DBP adsorption amount is less than 200ml / 100g, reinforcing property is not preferable, and if it exceeds 300ml / 100g, processability such as dispersibility It is not desirable because it can be a problem. If the carbon black alone or the total amount of carbon black and precipitated silica is outside the range of 30 to 100 parts by weight, there is a problem in maintaining required properties and improving processability, which is not preferable.

In the tire tread composition of the present invention, the hydrophilic inorganic material is preferably composed of 30 to 70% by weight of clay and 30 to 70% by weight of polymer, but beyond this range, the swelling properties of the hydrophilic groups are reduced, or the reinforcement is reduced by the hydrophilic inorganic material. It is not preferable because it may be a factor, and the content of the hydrophilic inorganic blend is preferably 5 to 30 parts by weight. If it is less than 5 parts by weight, the effect of improving the performance of wet traction is inadequate. It is not desirable to occur.

The polymer may be a natural rubber, butyl rubber, ethylene propylene diene rubber, styrene butadiene rubber or butadiene rubber having a hydrophilic group such as hydroxyl group, carboxyl group, amino group, sulfone group.

The rubber composition of the present invention may be further blended with the usual additives added to the general tread rubber composition, such as common zincation, stearic acid, sulfur and accelerators.

Hereinafter, the present invention will be described in more detail with reference to the following Examples and Comparative Examples. The following examples are merely examples for illustrating the present invention, and do not limit the protection scope of the present invention.

Example  And Comparative example

 After preparing the tire tread rubber compositions of Examples and Comparative Examples according to the composition of Table 1 below, rubber specimens were prepared from each rubber composition, vulcanized at 160 ° C., and then the physical properties thereof were measured according to ASTM standards. 2 is shown.

Table 1

(Unit: parts by weight)

Main item Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 S-SBR * 100 80 100 100 80 100 BR 0 20 0 0 20 0 Carbon black * 80 30 30 80 30 30 Silica * 0 50 50 0 50 50 Process oil 40 40 40 40 40 40 Mineral blend - - - 30 30 30 Zincification 3 3 3 3 3 3 Stearic acid One One One One One One brimstone 2 2 2 2 2 2 accelerant 1.6 1.6 1.6 1.6 1.6 1.6

* S-SBR: 40% by weight styrene, 25% by weight vinyl polymer solution styrene-butadiene rubber

* Carbon black: BET value 126m ² / g, DBP adsorption amount 120ml / 100g

* Silica: BET value 160m ² / g, DBP adsorption amount 280ml / 100g

TABLE 2

As shown in Table 2, compared to the rubber composition of the corresponding comparative example, the rubber composition of the Examples has improved the hardness, tensile strength and wear resistance, etc., the equivalent level or more, and wet traction performance in wet road conditions is greatly improved. It can be seen that the improvement.

As can be seen from the above, according to the present invention, by applying a hydrophilic inorganic blend to the raw material rubber mixed with solution-polymerized styrene butadiene rubber and butadiene rubber, the performance of hardness, tensile strength and abrasion resistance is improved to the same level or more. In addition, the wet traction performance on the wet road surface is greatly improved.

Claims (3)

Carbon based on 100 parts by weight of raw rubber comprising 20 to 50 parts by weight of styrene content, 60 to 100 parts by weight of solution-polymerized styrenebutadiene rubber having 20 to 50% by weight of vinyl in butadiene, and 0 to 40 parts by weight of butadiene rubber. A tire tread rubber composition comprising black alone, or 30-30 parts by weight of carbon black and precipitated silica in combination and 5-30 parts by weight of a hydrophilic inorganic blend composed of 30-70% by weight of clay and 30-70% by weight of polymer. According to claim 1, wherein the carbon black has a BET value of 100 ~ 180m ² / g, DBP adsorption amount of 80 ~ 160ml / 100g, The precipitated silica has a BET value of 120 ~ 200m ² / g, DBP adsorption amount of 200 Tire tread rubber composition, characterized in that ~ 300ml / 100g. The tire tread rubber composition according to claim 1, wherein the polymer in the hydrophilic inorganic blend is natural rubber, butyl rubber, ethylene propylene diene rubber, styrene butadiene rubber or butadiene rubber having a hydrophilic group.