KR20030042557A - Rubber composition for tire tread - Google Patents

Abstract

PURPOSE: A rubber composition for tire treads which has excellent wear resistance and improved chip-cut resistance and chunking resistance without increasing heat generation is provided. CONSTITUTION: The rubber composition for tire treads comprises a natural rubber or synthetic diene rubber, or a blend thereof and carbon black as a reinforcing agent. The rubber composition is characterized by comprising 0.2 to 15 parts by weight of n-tallow 1,3-propanediamine distearate represented by the formula £RH2N(CH2)3NH3|2+2 {C17H35COO}- wherein R is a C10-C40 aliphatic alkyl group, based on 100 parts by weight of the rubber. The n-tallow 1,3-propanediamine distearate can modify the surface of carbon black effectively.

Description

Rubber composition for tire treads {Rubber composition for tire tread}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rubber compositions for tire treads, and more particularly to tensile strength and tearing resistance by adding cationic surfactants as multi-functional additives to rubber compositions containing carbon black. Improved wear resistance, chip cut resistance and chunking resistance.

Tires consist of several parts, but tread rubber, among other things, has the most important influence on the wear performance of tires. Tire wear occurs when the tread rubber drops off continuously due to the friction between the road surface and the tires when the tire rotates.

However, the phenomenon in which the tread rubber falls to a large sized mass by external impact, that is, chip-cut and chunking, etc., often have a fatal effect on the wear performance of the tread rubber.

Therefore, in order to improve the abrasion resistance of the tread rubber, it is very important to simultaneously improve the abrasion resistance due to friction as well as the chip cut and the anti-chunking performance that can withstand external impacts.

In general, the wear performance of the tire is greatly affected by carbon black, but as the current technology, various carbon blacks have been developed to show good performance and new carbon blacks are being developed.

However, as new manufacturing methods and methods are added to obtain improved carbon black properties compared to current products, the price is likely to increase relatively. Therefore, methods for obtaining improved wear resistance while using existing carbon blacks are being developed. These methods often have advantages in terms of wear performance and price.

For example, many methods for modifying the surface of carbon black are used. The method includes chemically modifying the surface by adding a new process in the manufacturing process and adding an additive to the rubber composition in the rubber composition. There is a method of modifying the surface of carbon black during processing.

In addition, in order to improve the chip cut resistance and the anti-chunking performance, it has been known to increase the strength and elongation at break, thereby improving the breaking energy and increasing the tearing energy.

Conventionally, in order to improve the strength and elongation at break, a resin was used or a method such as changing the crosslinking structure was used to favor these properties, but the results were not satisfactory.

Therefore, it is urgent to develop a tread rubber that can improve chip cut resistance and chunking performance without deteriorating wear resistance.

Accordingly, the present inventors have been researching to improve the wear performance of the tire tread rubber and improve the chip cut resistance and the anti-chunking resistance, and by adding a cationic surfactant as a multifunctional additive to the conventional rubber composition, the surface of the carbon black has been improved. The present invention was completed by finding that the overall wear resistance was improved without modifying the exotherm.

Accordingly, it is an object of the present invention to provide a rubber tread rubber composition which is excellent in wear resistance, can improve chip cut resistance and chunking, and does not increase heat generation.

The rubber composition for tire treads of the present invention for achieving the above object is n-tallow 1,3-propanediamine distea which is a cationic surfactant in 100 parts by weight of natural rubber or diene synthetic rubber alone or blends thereof. It is characterized by the fact that it is made by adding 0.2-15 weight part of rates.

The present invention will be described in more detail as follows.

The present invention adds a cationic surfactant as a multifunctional additive to a rubber tread rubber composition containing carbon black.

As the rubber used in the present invention, natural rubber or diene-based synthetic rubber is used alone as in a conventional tire tread rubber composition, or a rubber obtained by blending the natural rubber and diene-based synthetic rubber at a predetermined ratio is used as a main component. .

And carbon black is used as a normal reinforcing agent. Carbon black is usually added in an amount of 40 to 60 parts by weight based on the characteristics of carbon black with respect to 100 parts by weight of the rubber.

On the other hand, the present invention uses a cationic surfactant as a multifunctional additive to modify the surface of the carbon black in the rubber composition, and improve the overall wear resistance without increasing the heat generation.

Such cationic surfactants are n-tallow 1,3-propanediamine distearate, such as the following Chemical Formula 1, and may be added in an amount of 0.2 to 15 parts by weight, preferably 1 to 4 parts by weight, based on 100 parts by weight of the rubber. to be.

If the content is less than 0.2 parts by weight, the surface modification effect of carbon black is insufficient, and if it exceeds 15 parts by weight, it is not only disadvantageous to wear resistance but also economically unfavorable.

Formula 1

[RH ₂ N (CH ₂ ) ₃ NH ₃ ] ²⁺ ₂ {C ₁₇ H ₃₅ COO} ^-

In the above formula, R is an aliphatic alkyl group having 10 to 40 carbon atoms.

In addition, in the present invention, of course, in addition to the composition of the present invention, an antioxidant, a softener, a vulcanizing agent, a vulcanization accelerator, and the like used as a general rubber compounding agent may be blended at an appropriate level.

On the other hand, the manufacturing process of the tire tread rubber according to the composition of the present invention follows a conventional process.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not limited thereto.

Examples 1-3

As shown in Table 1 below, each component was combined to prepare a rubber composition.

The obtained rubber was used to measure tensile strength, tensile modulus, elongation, tearing strength, amount of rambon wear and dynamic loss factor (tan δ), and the results are shown in Table 2 below.

Composition (part by weight) Example 1 Example 2 Example 3 Comparative Example 1 Natural rubber 100 100 100 100 Cationic Surfactants ⁽¹⁾ One 3 6 - Carbon black 50 50 50 50 Zinc oxide 3 3 3 3 Stearic acid 2 2 2 2 Anti-aging 2 2 2 2 brimstone 1.5 1.5 1.5 1.5 Accelerators ⁽²⁾ 1.0 1.0 1.0 1.0 (1) (n): n- tallow 1, 3- propanediamine distearate (2): N-t- butyl- 2-benzodiazyl- sulfenamide

Properties Example 1 Example 2 Example 3 Comparative Example 1 Tensile Strength (kg / ㎠) 310 330 320 290 Tensile Modulus (kg / ㎠) 145 140 130 145 Elongation (%) 550 570 580 530 Tearing Strength (kg / ㎠) 90 110 102 85 Rambon Wear (cc) ⁽¹⁾ 0.466 0.416 0.442 0.519 Dynamic loss factor (tan δ, 60 ℃) 0.0941 0.0945 0.0988 0.0944 (1) (1): Abrasion test normally used in the rubber industry (measured at room temperature and slip ratio of 25%). Dynamic Loss Coefficient Measured at 10Hz frequency at 0.5% strain using a twisted type viscoelastic tester with varying temperature.

From the results in Table 2, by adding n-tallow 1,3-propanediamine distearate, which is a cationic surfactant of the present invention, to a conventional rubber tread rubber composition, excellent wear resistance, tensile strength, elongation, tearing It can be confirmed that the mechanical properties such as strength is excellent.

As described in detail above, as a result of using n-tallow 1,3-propanediamine distearate as a cationic surfactant in the rubber composition for tire treads of the present invention, by effectively modifying the surface of the carbon black, the heat generation is not increased. It has excellent wear resistance, which results in improved chip cut resistance and chunking resistance.

Claims (1)

In a rubber composition for tire treads comprising carbon black as a reinforcing agent in natural rubber or diene-based synthetic rubber alone or in blends thereof, The composition is a tire composition for a tire tread, characterized in that it comprises 0.2 to 15 parts by weight of n- tallow 1,3-propanediamine distearate represented by the following formula (1) based on 100 parts by weight of the rubber. Formula 1 [RH ₂ N (CH ₂ ) ₃ NH ₃ ] ²⁺ ₂ {C ₁₇ H ₃₅ COO} ^- In the above formula, R is an aliphatic alkyl group having 10 to 40 carbon atoms.