KR100570266B1 - Silica and Silane Coupling Reinforced Silica Tread Compound - Google Patents

Abstract

The present invention relates to a silica rubber composition reinforced with silica and a silane coupling agent, and more particularly, to a silica rubber composition capable of inducing high dispersion of silica to minimize energy consumption and maintain high temperature stability.

The present invention relates to a silica rubber composition comprising a solution-polymerized styrene-butadiene rubber or a mixture of a solution-polymerized styrene-butadiene rubber and butadiene rubber as a raw material rubber, wherein the BET value is 130 to 200 m 2 / g based on 100 parts by weight of the raw material rubber. A silica rubber composition reinforced with silica and a silane coupling agent is provided, which contains 40 to 90 parts by weight of precipitated silica and 4 to 11 weight% of a silane coupling agent based on the silica.

Description

Silica rubber composition reinforced with silica and silane coupling agent {Silica and Silane Coupling Reinforced Silica Tread Compound}

The present invention relates to a silica rubber composition reinforced with silica and a silane coupling agent, and more particularly, to a silica rubber composition capable of inducing high dispersion of silica to minimize energy consumption and maintain high temperature stability.

Recently, silica is often used as a reinforcing filler in tire rubber compositions, but when silica is used, it causes viscosity increase due to poor dispersion of rubber composition and deterioration of rubber properties due to gelation reaction when left for a long time. The dispersibility of a silica is improved using a preparation, process oil, and a coupling agent.

In the conventional tread rubber composition for passenger cars, silica has been used to have low rotational resistance characteristics, but when silica is used alone, it has a strong hydrophilic group and thus dispersibility due to interaction between fillers Low tires cause irregular wear.

In order to overcome this disadvantage, a silane coupling agent is used to eliminate the interaction between the fillers as much as possible to increase the dispersibility in the rubber composition, the silane coupling agent of the silica surface used as a reinforcing agent Although it plays a role of crosslinking between silanol group and rubber of rubber composition, it is expensive and has disadvantages such as ethanol volatilization in the process, but when used by silica alone, strong cohesion between silica and silica Giving functions.

As a coupling agent that has been generally used in the prior art, tetraethoxysilyl propyl tetrasulfide (TESPT), which is not stable in high temperature mixing at 160 ° C, consumes a lot of energy, and has a disadvantage of causing gelation when left for a long time. there was.

The present inventors continue to study to solve the above problems and find out that the above problems can be solved by using a new coupling agent which is excellent in high temperature stability and can increase the dispersibility of silica. It was.

Accordingly, it is an object of the present invention to provide a new silica rubber composition that can induce high dispersion of silica by reinforcing silica and silane coupling agent to minimize energy consumption and maintain high temperature stability.

The present invention is a silica rubber composition comprising a raw material rubber of solution-polymerized styrene-butadiene rubber or mixed rubber of solution-polymerized styrene-butadiene rubber and butadiene rubber as a means for achieving the above object, 100 parts by weight of raw rubber Silica and silane coupling agent-reinforced silica rubber, comprising 40 to 90 parts by weight of precipitated silica having a BET value of 130 to 200 m 2 / g and a silane coupling agent of 4 to 11% by weight relative to the silica. To provide a composition.

The silica rubber composition according to the present invention may be used as either a raw rubber or a mixed rubber of natural rubber and synthetic rubber, but a solution-polymerized styrene-butadiene rubber single component or a solution-polymerized styrene-butadiene rubber 60 to 90 parts by weight Preferred is a mixed rubber composed of 10 to 40 parts by weight of butadiene rubber.

The silane coupling agent used in the silica rubber composition according to the present invention is 3-octanoylthio-1-propyltriethoxy in which one group is composed of mercaptosilane and the other group is composed of octanoyl groups. As silane (3-octanoylthio-1-propylethoxy silane), it has the advantage of much higher safety even at high temperature of 175 ° C or higher, and increases the dispersibility of silica in a high-loading silica rubber composition to decrease the viscosity and further extend the scorch time. It can function to improve rotational resistance, braking performance and abrasion performance.

In addition, by using 4 to 11% by weight, preferably 4 to 8% by weight of silica, the amount of tetraethoxysilyl propyl tetrasulfide used as a conventional coupling agent can be reduced more than 6 to 10% by weight. There is an advantage, when using less than 4% by weight can not exert the cross-linking role of the rubber and silica, there is also a problem that the dispersibility of the silica in the rubber compound due to a small amount of application. In addition, when the amount exceeds 11% by weight, the modulus and hardness due to gelation increase rapidly due to the excessive amount of use, and there is a problem that a scorch phenomenon due to gelation may occur during extrusion.

Silica rubber compositions reinforced with silica and silane coupling agents according to the present invention can be used as tread rubber compositions for passenger cars, tread rubber compositions for trucks, and tread rubber compositions for buses.

Other components included in the silica rubber composition reinforced with silica and silane coupling agent according to the present invention, for example, zincated, active agents such as stearic acid, antioxidants, process oils, vulcanizing agents and vulcanization accelerators are known from known silica rubber compositions. As the additives, each of them is sufficient to be appropriately carried out according to a range of known amounts of addition, so detailed description thereof is omitted.

Hereinafter, the content of the present invention will be described in detail through Examples and Comparative Examples. However, the following examples are intended to illustrate the present invention in more detail, and the scope of the present invention is not intended to be limited thereto.

<Example 1>

80 parts by weight of silica, 2.5 parts by weight of zinc and 2.5 parts by weight of silane coupling agent based on 103.2 parts by weight of solution-polymerized styrene-butadiene rubber and 25 parts by weight of butadiene rubber as a raw material rubber as shown in Table 1 Silica rubber composition was prepared by adding 7.8 parts by weight of propyltriethoxysilane, 1.4 parts by weight of vulcanizing agent, and 1.7 parts by weight of main promoter and 2.0 parts by weight of promoter to vulcanization accelerator, and mixing the mixture into a half-barrier and releasing it at a temperature of 105 ° C. It was.

<Example 2>

A silica rubber composition was prepared under the same conditions as in Example 1 except that 9.7 parts by weight of 3-octanoylthio-1-propyltriethoxysilane was added as the silane coupling agent.

Comparative Example

A silica rubber composition was prepared under the same conditions as in Example 1 except that 5.6 parts by weight of tetraethoxysilyl propyltetrasulfide was added as the silane coupling agent.

  <Table 1> Compounding ratio (unit: parts by weight)

division Example 1 Example 2 Comparative example Solution Polymerized Styrene-Butadiene Rubber 103.2 103.2 103.2 Butadiene rubber 25 25 25 Silica 80 80 80 Zincification 2.5 2.5 2.5 Stearic acid 1.0 1.0 1.0 Anti-aging 2.0 2.0 2.0 Silane Coupling Agent 1 7.8 9.7 - Silane Coupling Agent 2 - - 5.6 Vulcanizing agent 1.4 1.4 1.4 Stock price accelerator 1.7 1.7 1.7 Poultry Accelerator 2.0 2.0 2.0

Silane Coupling Agent 1: 3-octanoylthio-1-propyltriethoxysilane

Silane coupling agent 2: tetraethoxysilyl propyl tetrasulfide

<Test Example>

The rubber composition prepared in Example 1, Example 2 and Comparative Example was quenched at 160 ° C. for 15 minutes to prepare a tensile test specimen, followed by processability, tensile properties, exothermic and rebound characteristics, dynamic viscoelastic properties, and the like according to ASTM standards. The results of measuring the wear characteristics are shown in Table 2 below.

      <Table 2> Property Test Results

division Example 1 Example 2 Comparative example Processability 100 ℃ Viscosity 125 ℃ Viscosity Scorching Time (t5) Maximum Torque Minimum Torque Curvature Time (t90)  124 96 46.5 47.1 19.5 19.5  106 78 46.3 43.8 18.3 20.3  129 99 34.0 48.6 27.1 23.5 Tensile Properties Hardness 300% Modulus (Kgf / ㎠) Tensile Strength (Kgf / ㎠) Elongation (%)  66 100 206 523  67 105 207 550  69 114 223 504 Exothermic (℃) Rebound (1st) 29.9 32.4 28.1 35.6 32.5 30.8 Dynamic Viscoelasticity (RV) Tg (℃) Tan Delta 0 ℃ Tan Delta 70 ℃  -25.5 0.272 0.126  -29.4 0.275 0.118  -23.5 0.270 0.136 Pico-Mo / Din-Mo (g) 0.0305 / 0.142 0.0265 / 0.138 0.0320 / 0.142

As can be seen from the above results, the unvulcanized properties of the silica rubber composition according to the present invention show a low viscosity, maximum torque and minimum torque of the rheometer, thereby improving processability. It can be seen that the basic properties, such as hardness, tensile strength, and 300% modulus, show low values.

In particular, heat generation and rebound characteristics are improved, and in the case of dynamic viscoelastic characteristics, 0 ° C

The tan δ value is higher than that of the comparative example, and the tan δ value of 70 ° C. shows low characteristics, showing low braking force as well as low rolling resistance on a wet road surface, and also shows a significant improvement in wear characteristics.

The silica rubber composition according to the present invention uses 3-octanoylthio-1-propyltriethoxysilane as a silane coupling agent to reduce the viscosity of the rubber composition, thereby reducing shrinkage during extrusion, and to maintain a low level of physical properties. It is possible to provide a silica rubber composition reinforced with silica and silane coupling agent with improved rotational resistance and braking performance.

Claims (3)

In a silica rubber composition comprising, as a raw material rubber, solution-polymerized styrene-butadiene rubber or a mixture of solution-polymerized styrene-butadiene rubber and butadiene rubber, 40 to 90 parts by weight of precipitated silica having a BET value of 130 to 200 m 2 / g with respect to 100 parts by weight of a raw material rubber composed of 60 to 90 parts by weight of solution-polymerized styrene-butadiene rubber and 10 to 40 parts by weight of butadiene rubber, and 4 to Silica and a silica rubber composition reinforced with a silane coupling agent, characterized by containing a silane coupling agent of ~ 11% by weight. delete The method of claim 1, Silane and silica rubber composition reinforced with silane coupling agent, characterized in that the silane coupling agent is 3-octanoylthio-1-propyltriethoxysilane in which one group consists of mercaptosilane and the other group consists of octanoyl groups. .