KR20030028639A - Tread compound for truck and bus tire - Google Patents

Abstract

PURPOSE: A tire tread rubber composition for a truck and a bus is provided, to improve the abrasion resistance and the attrition resistance by controlling the content of stearic acid and employing a mixture of a liquid isoprene rubber without using a aromatic oil as a pollutant. CONSTITUTION: The tire tread rubber composition comprises 100 parts by weight of a natural rubber; 0.2-0.7 parts by weight of a mixture of 2,2'-dibenzamidediphenyldisulfide and Fe-porphyrazine in the ratio of 1:2 instead of a process oil as a processing agent; 3-6 parts by weight of a liquid isoprene rubber; and 3-7 parts by weight of stearic acid. Preferably the ratio of the mixture of 2,2'-dibenzamidediphenyldisulfide and Fe-porphyrazine to stearic acid is 1:3 to 1:15 by weight.

Description

Tread compound for truck and bus tire

The present invention is a tire tread rubber composition for truck buses, and more specifically, a tire tread rubber composition for truck buses with improved wear and abrasion resistance without using aromatic oils that are emerging as environmentally harmful substances. It is about.

The tread part of a tire is a part which directly contacts a road surface, and is a thick rubber layer. In order to protect the carcass and the belt layer inside the tire, rubber is used that is strong against cuts and impacts and also wear-resistant rubber to increase the running life of the tire.

Compounding processes used mainly in the tire industry, such as paraffin oil and aromatic oil, which are added to minimize the force applied to the equipment and make the process smooth during the tire compounding process, are currently hazardous substances. The movement to restrict the use by handling is spreading in Europe and around the world, and also in terms of the performance of the tire after compounding, it causes the hardness of the rubber composition after the residence process and a decrease in wear resistance.

For this reason, research on process oils is underway, and a method of using oils that minimize benzenes and harmful substances contained in process oils has been attempted, but in this case, a significant increase in cost and glass transition temperature in the properties of the rubber composition There is a problem that there is a limitation in applying to mass production because it causes a significant decrease in wear resistance due to a significant change in glass transition temperature.

The inventors of the present invention, while performing research to solve the above problems, instead of using a conventional process oil by improving the physical properties of the rubber composition through the mixed use of the process agent and the liquid isoprene rubber and the amount of stearic acid added It has been found that the same problem can be overcome and the present invention has been completed.

Accordingly, an object of the present invention is to provide a tire tread rubber composition for truck buses having improved wear and abrasion resistance without using aromatic oils that are emerging as environmentally harmful substances.

The present invention relates to a tire tread rubber composition for truck buses comprising a known additive, wherein 2,2'-dibenzamidediphenyldisulfide is used as a process agent instead of process oil based on 100 parts by weight of natural rubber. ) And 0.2-0.7 parts by weight of a mixture of Fe-porphyrazine 1: 2, 3-6 parts by weight of liquid isoprene rubber, and 3-7 parts by weight of stearic acid. It is characterized by the tire tread rubber composition for truck bus.

The tread rubber composition according to the present invention can solve the conventional problems to some extent in terms of process when the process agent or the liquid isoprene rubber is used alone instead of the process oil, but exhibits a slight effect in terms of improving physical properties. When 3 parts by weight or more is used, the hardness and abrasion resistance properties of the rubber composition are remarkably improved.

The amount of the mixture of 2,2'-dibenzamide diphenyldisulfide and iron-polazine 1: 2 and stearic acid used in the present invention is preferably in the range of 1: 3-1: 1, but the amount is 1: 3. In the following ranges, there is a problem in that the viscosity reduction effect and the hardness and abrasion resistance effect in the physical properties are insignificant, and in the range of 1:15, there is a problem that the dimensional stability (dimension stability) is unstable.

The liquid isoprene rubber used in the present invention preferably has a cis content of 94% or more and a molecular weight of 2,000-10,000. The liquid isoprene rubber functions as a pre-vulcanization fairing agent in the rubber composition to lower the viscosity, but an aromatic oil Unlike this, it does not affect the physical properties after vulcanization at all.

Other components included in the tread rubber composition according to the present invention, for example, carbon black, zinc oxide, anti-aging agent, vulcanizing agent, vulcanization accelerator, etc. are known additives of tire tread rubber composition for truck buses, each of which is already known. It is sufficient to select and carry out according to the range of addition amount, but use 30-80 parts by weight of carbon black having 30-80 mg / g of iodine adsorption and 40-120 cm 3 / 100g of DBP oil absorption to 100 parts by weight of natural rubber It is preferable to use sulfur and / or sulfur donor type vulcanizing agents as vulcanizing agents, sulfenamide type accelerators as vulcanization accelerators, and amine compounds as anti-aging agents.

Hereinafter, the contents 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 are not intended to limit the scope of the invention.

<Example 1>

A mixture of 50 parts by weight of carbon black, 2,2'-dibenzamide diphenyldisulfide, and iron-polazine 1: 2 ratio based on 100 parts by weight of natural rubber as a raw material rubber as shown in Table 1 (manufactured by Rhenchemi) Melting point 50-60 ° C. or less GE-1525) 0.4 parts by weight, liquid isoprene rubber (hereinafter LIR-50) 5 parts by weight, stearic acid 3 parts by weight, zinc oxide 3 parts by weight, free sulfur 2 parts, accelerator 1.2 By weight, 4.5 parts by weight of the anti-aging agent was added to the half-barrier mixer and released at a temperature of 105 ℃ to prepare a tread rubber composition.

N-t-cyclohexyl-2-benzothiazole sulfenamide, a sulfenamide-based accelerator, was used as an accelerator.

<Example 2>

Example 1 except that 0.7 parts by weight of a mixture of 2,2'-dibenzamide diphenyldisulfide and iron-polarazine in a 1: 2 ratio, 4 parts by weight of liquid isoprene rubber and 5 parts by weight of stearic acid were used. It was carried out under the same conditions as to prepare a tread rubber composition.

<Example 3>

In Example 1, except that the mixture of 2,2'-dibenzamide diphenyldisulfide and iron-polazine 1: 2 ratio was 0.2 parts by weight, 4 parts by weight of liquid isoprene rubber and 2 parts by weight of stearic acid. It was carried out under the same conditions as to prepare a tread rubber composition.

Comparative Example

Except for using a mixture of 2,2'-dibenzamide diphenyldisulfide and iron-polazine 1: 2 ratio and liquid isoprene rubber, 7 parts by weight of aromatic process oil and 1.5 parts by weight of stearic acid are used. A tread rubber composition was prepared under the same conditions as in Example 1.

<Table 1> Compounding Ratio (Unit: parts by weight)

division Example 1 Example 2 Example 3 Comparative example Natural rubber 100 100 100 100 Carbon black 50 50 50 50 Process oil - - - 7 GE1525 0.4 0.7 0.2 - LIR-50 5 4 4 - Stearic acid 3 5 2 1.5 Zinc oxide 3 3 3 3 brimstone 2 2 2 2 accelerant 1.2 1.2 1.2 1.2 Anti-aging 4.5 4.5 4.5 4.5

<Test Example 1>

The rubber compositions prepared in Examples and Comparative Examples were quenched at 160 ° C. for 15 minutes to prepare tensile specimens, such as viscosity, 300% modulus, tensile strength, elongation, wear resistance, 0 ° C. delta and exothermic properties. Physical properties of the rubber compound were measured according to ASTM standard, and the results are shown in Table 2.

At this time, the viscosity was measured using a pattern tester, and the wear characteristics were measured using a PICO tester (BF Goodrich Co., Ltd.), and the weight loss of rubber was measured after rotating the specimen 80 times. The value was calculated | required by the formula.

tan δ = loss modulus (E '') / storage modulus (E '')

The index value shown in Table 2 is a relative comparison value which made the comparative example 100, and the higher the index, the better the performance.

<Table 2> Property Measurement Results

division Example 1 Example 2 Example 3 Comparative example Viscosity (125 ℃) 62 60 65 65 300% modulus (kg / ㎠) 132 135 130 127 Tensile Strength (kg / ㎠) 290 291 268 287 Elongation (%) 546 555 531 540 Wear Resistance (PICO) 0.019 0.021 0.031 0.045 Tan Delta (0 ℃) 0.171 0.166 0.165 0.161 Fever (℃) 22 23 22 25

As shown in Table 2, the specimens using a mixture of 2,2'-dibenzamide diphenyldisulfide and iron-polarazine 1: 2 ratio and liquid isoprene rubber without using process oil were lower than those of the comparative rubber samples. It can be seen that it has tensile properties, low heat generation and excellent wear resistance while maintaining the viscosity.

<Test Example 2>

11R22.5 standard tires were manufactured according to a conventional method using the tread rubber composition according to the present invention, and then mounted on an express bus front wheel to evaluate wear resistance. The results are shown in Table 2.

At this time, the index value is a relative comparison value using the comparative example as 100, which means that the higher the index, the better the performance.

Table 3 Performance of Tires Made from Rubber Compositions According to the Present Invention

division Example 1 Example 2 Example 3 Comparative example Wetting resistance 109 110 107 100 Wear Resistance Index 117 115 110 100

As shown in Table 2, tires using a mixture of 2,2'-dibenzamidediphenyldisulfide and iron-polazine 1: 2 ratio and 3 parts by weight or more of stearic acid, instead of aromatic oil, which is a process oil, showed excellent wear performance. Able to know.

The tire tread rubber composition for truck buses according to the present invention has an effect of improving wear and abrasion resistance without using aromatic oils that are emerging as environmentally harmful substances.

Claims (2)

In the tire tread rubber composition for truck bus comprising a known additive, 0.2-0.7 parts by weight of a mixture of 2,2'-dibenzamidediphenyldisulfide and iron-polarazine in a ratio of 1: 2 and 3-6 parts by weight of liquid isoprene rubber, instead of process oil, based on 100 parts by weight of natural rubber A tire tread rubber composition for truck buses, comprising 3-7 parts by weight of stearic acid. The tire tread rubber for truck buses according to claim 1, wherein the amount of the mixture of 2,2'-dibenzamide diphenyldisulfide and iron-polazine 1: 2 and stearic acid is 1: 3-1: 1. Composition.