KR100656557B1 - Tire tread composition filed silica - Google Patents

Abstract

Provided are a tire tread rubber composition which is excellent in wet traction, rolling resistance, heat build-up characteristics and rebound characteristics, and a tire containing the rubber comprising the composition. The tire tread rubber composition comprises 40-80 parts by weight of a silica having a BET surface area of 100-400 m^2/g and a CTAB surface area of 350 m^2/g or less based on 100 parts by weight of a rubber material; and 8-10 % of liquid polybutadiene as a coupling agent to the content of the silica. Preferably the liquid polybutadiene has a primary hydroxyl group or a secondary hydroxyl group.

Description

Tire tread composition filed silica

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire tread rubber composition containing silica, and more particularly, to a tire tread rubber composition using conventional silica as a filler, wherein the primary hydroxyl group or the secondary hydroxyl group is used. The present invention relates to a tire tread rubber composition capable of improving liquid dispersibility of silica by including liquid polybutadiene having a group) as a coupling agent to improve rotational resistance characteristics and braking force on a wet road surface.

The use of silica as a reinforcing filler is increasing in order to have low fuel efficiency and environmentally friendly characteristics in the tread rubber composition of automobile tires, especially passenger car tires.

Silica has a hydrophilic group, and when silica is used as a reinforcing filler alone, other additives added to the rubber composition and the reactivity with the rubber are weak, and since the silica tends to agglomerate with each other, the rubber composition has a weak dispersibility problem. have.

When the rubber is agglomerated with each other in the rubber composition to produce a rubber and apply it to a tire tread, there is a problem in that the wear characteristic is reduced in the tire, thereby reducing the wear characteristics.

In order to solve this problem, most rubber compositions using silica as a reinforcing filler use a coupling agent to improve dispersibility of silica.

Conventionally, a silane coupling agent based on silane is widely used as a coupling agent for silica.

The silane coupling agent acts as a crosslinking link between the silanol group on the silica surface and the raw rubber of the rubber composition. However, the silane coupling agent has the disadvantages of high price and volatilization of ethanol during the process, but due to the strong cohesiveness of silica alone, It acts to crush strong cohesion.

As the silane coupling agent, bis-3-triethoxysilylpropyl tetrasulfide (TESPT) or bis-3-triethoxysilylpropyl disulfide (TESPD) is mainly used. Polysulfide has a low stability at high temperatures, high energy consumption during blending, and a problem of reacting during the mixing process rather than the vulcanization process.

The present invention devised to solve the above-mentioned problem is a silica tread rubber composition containing silica as a coupling agent of silica and silica having a BET surface area of 100 to 400 m ² / g and a CTAB surface area of 350 m ² / g or less. It is an object to provide a tire tread rubber composition comprising a liquid polybutadiene having a primary hydroxy group or a secondary hydroxy group.

Meanwhile, the present invention includes a tire containing a tread composed of a tire rubber composition comprising silica as a reinforcing filler and a liquid polybutadiene having a primary hydroxy group or a secondary hydroxy group as a silica coupling agent.

The tire tread rubber composition of the present invention uses silica as a reinforcing filler and includes liquid polybutadiene having a primary hydroxy group or a secondary hydroxy group as a silica coupling agent to improve rotation resistance and braking power on wet road surfaces. You can.

In order to achieve the above-mentioned object, the present invention is a tire tread rubber composition containing silica, which has a BET surface area of 100 to 400 m ² / g and a CTAB surface area of 350 m ² / g or less based on 100 parts by weight of raw rubber. The tire tread rubber composition which contains 40 to 80 weight part and 8 to 10% of a liquid polybutadiene compared with a silica content as a coupling agent is shown.

In the present invention, the raw material rubber can be used as long as it can be used as the raw material rubber of the conventional tire tread rubber composition.

In the present invention, as the raw material rubber, any one or more selected from natural rubber and synthetic rubber may be used as the raw material rubber.

As an example of the raw material rubber in the present invention it can be used mixed rubber mixed with natural rubber and synthetic rubber in the ratio of 1: 9 to 9: 1. In addition, mixed rubbers in which two kinds of synthetic rubbers are mixed in a ratio of 1: 9 to 9: 1 can be used. And it is possible to use a mixed rubber of two or more kinds of synthetic rubber mixed with each other.

The synthetic rubber may be any one or more selected from styrene butadiene rubber, butadiene rubber, styrene butadiene rubber containing isoprene, styrene butadiene rubber including nitrile and neoprene rubber.

Silica used as a reinforcing filler in the present invention may be used as long as the silica used as a reinforcing filler in a conventional tire tread rubber composition.

As an example of silica used as a reinforcing filler in the present invention, silica having a BET surface area of 100 to 400 m ² / g, CTAB surface area of 350 m ² / g or less, and more preferably 150 to 350 m ² / g of CTAB surface area can be used. .

The silica used as the reinforcing filler in the present invention may include 40 to 80 parts by weight based on 100 parts by weight of the raw material rubber. If the content of silica is less than 40 parts by weight, there is a problem that the physical properties of the tread rubber composition is reduced, and if it exceeds 80 parts by weight, the tendency of the silica to aggregate with each other increases, so that the physical properties of the rubber composition may be reduced. Therefore, in the tire tread rubber composition of the present invention, the silica may preferably contain 40 to 80 parts by weight based on 100 parts by weight of the rubber material.

In the present invention, when the content of silica is less than 50 parts by weight, that is, 40 to 50 parts by weight based on 100 parts by weight of the raw material rubber, carbon black 10 to 30 parts by weight may be further used as a reinforcing filler.

In the present invention, a liquid polybutadiene having a primary hydroxy group or a secondary hydroxy group may be used as a coupling agent for improving the dispersibility of the silica.

In the present invention, as an example of the liquid polybutadiene, a substance of the following structural formula (1) or (2) may be used.

(CH ₂ -CH = CH-CH ₂ ) n-(CH ₂ -CH ₂ -OH) ₂ ... Structural formula (1)

(CH ₂ -CH = CH-CH ₂ ) n-(CH ₂ -CH (CH ₃ ) -OH) ₂ ... Structural formula (2)

In the materials of the above formulas (1) and / or (2), molecular weights of 10,000 to 100,000 may be used.

In the tire tread rubber composition of the present invention, the liquid polybutadiene as a silica coupling agent may be used in an amount of 5 to 15% based on the silica content, and preferably 8 to 10% based on the silica content.

When the liquid polybutadiene is used in less than 5% of the silica content, the role as a silica coupling agent is insignificant, and when used in excess of 15% there is no significant increase in the silica dispersibility and there is a fear that the physical properties are reduced. Therefore, in the present invention, the silica coupling agent, the liquid polybutadiene, which is a silica coupling agent, may be used in an amount of 5 to 15% relative to the silica content.

According to the present invention, various additives such as reinforcing fillers, activators, anti-aging agents, process oils, vulcanizing agents, and vulcanization accelerators used in conventional tire tread rubber compositions, in addition to the above-mentioned raw rubber, silica, and liquid polybutadiene, are appropriately selected as necessary. It can be used in a predetermined content. However, these are general components used in conventional tire tread rubber compositions, and thus are not essential components of the present invention, and thus the detailed descriptions thereof will be omitted.

On the other hand, the present invention includes a tire containing a tread made of the tire tread rubber composition. In this case, the tire includes any one selected from tires for automobiles, tires for trucks, and tires for buses.

Hereinafter, the present invention will be described by the following comparative examples, examples and test examples. However, these are not limited to the scope of the present invention by these as an embodiment of the present invention.

<Example 1>

Rubber specimens were prepared using the composition components of Table 1.

Styrene butadiene rubber is used as a raw material rubber, and based on 100 parts by weight of raw material rubber, 72 parts by weight of silica, 4 parts by weight of zinc oxide (ZnO), 2 parts by weight of stearic acid, and an antioxidant (2,2,4-trimethyl- 2 parts by weight of 1,2-dihydroquinoline) and 5.8 parts by weight of liquid polybutadiene (LBH-P2000) were placed in a Banbury mixer and mixed at 120 ° C. for 20 minutes.

Then, 1.5 parts by weight of sulfur, a vulcanizing agent, 1 part by weight of vulcanization accelerator (N-t-butylbenzothiazole sulfenamide, NS), and 1.0 part by weight of vulcanization accelerator (DPG) were added to cure at 160 ° C. for 30 minutes to prepare a rubber specimen.

The liquid polybutadiene has a molecular weight of 50,000 and the following structural formula (1) was used.

(CH ₂ -CH = CH-CH ₂ ) n-(CH ₂ -CH ₂ -OH) ₂ ... Structural formula (1)

<Example 2>

A rubber specimen was prepared in the same composition and method as in Example 1 except that the molecular weight was 55,000 and 5.8 parts by weight of liquid polybutadiene (LBH-2000) of Structural Formula (2) was used.

(CH ₂ -CH = CH-CH ₂ ) n-(CH ₂ -CH (CH ₃ ) -OH) ₂ ... Structural formula (2)

Comparative Example

A rubber specimen was prepared in the same composition and method as in Example 1 except that 5.8 parts by weight of bis-3-triethoxysilylpropyl tetrasulfide (TESPT) was used as the silane coupling agent instead of the liquid polybutadiene.

Table 1. COMPARATIVE EXAMPLES AND EXAMPLES Composition Components of Rubber (Unit: parts by weight)

Item Comparative example Example 1 Example 2 Raw material rubber 100 100 100 Silica 72 72 72 Zinc oxide 4 4 4 Stearic acid 2 2 2 Anti-aging 2 2 2 TESPT 5.8 - - LBH-P2000 - 5.8 - LBH-P2000 - - 5.8 brimstone 1.5 1.5 1.5 Vulcanization accelerator (NS) 1.5 1.5 1.5 Vulcanization accelerator (DPG) 1.0 1.0 1.0

<Test Example>

The physical properties of the rubber specimens of the Comparative Example and the rubber specimens of the Example were measured by ASTM-related regulations and the results are summarized in Table 2 below.

Table 2. Physical Properties of Comparative Examples and Examples

Item Comparative example Example 1 Example 2 100 ℃ viscosity 101 96 95 125 ℃ viscosity 98 71 70 Scorch time (t5) 15.9 22.9 22.4 Torque 38 36 38 Torque 16 216 17 Rush time (t90) 10.3 10.3 10.3 Hardness 77 77 77 300% modulus (kg / cm ² ) 153 157 161 Tensile Strength (kg / cm ² ) 218 223 231 Elongation (%) 367 526 407 Fever (temperature difference) 32.5 31.7 30.8 Rebound (1st) 11.9 12.0 11.8 Glass transition temperature (Tg, ℃) -10.1 -9.8 -8.3 Tanδ (0 ℃) 0.531 0.572 0.621 Tanδ (70 ° C) 0.198 0.187 0.181

As shown in the results of Table 2, the unvulcanized properties and the basic properties of the tensile strength, 300% modulus of Examples 1 and 2 compared to the comparative example showed more than the equivalent level, the heat generation and rebound characteristics are improved.

In addition, the value of Tanδ (0 ° C.) is high and the value of Tanδ (70 ° C.) is low in dynamic viscoelastic properties, indicating that braking force and rolling resistance on wet roads are excellent.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

Claims (3)

In a tire tread rubber composition containing silica, Tire tread containing 40 to 80 parts by weight of silica having a BET surface area of 100 to 400 m ² / g, CTAB surface area of 350 m ² / g or less, and a coupling agent of 8 to 10% of the liquid polybutadiene relative to the silica content Rubber composition. The tire tread rubber composition according to claim 1, wherein the liquid polybutadiene has a primary hydroxy group or a secondary hydroxy group. A tire comprising a rubber made of the rubber composition of claim 1 as a tread.