KR20030019982A - Tread rubber composition for snow tire - Google Patents

Abstract

PURPOSE: Provided is a tread rubber composition for a snow tire, which contains silica and can maximize driving force and brake force in a snow road and a wet road by adding a foaming agent. CONSTITUTION: The tread rubber composition contains a raw rubber comprising a natural rubber and a synthetic rubber in the ratio of 3:7-5:5, the silica, as a filler, substituted wholly or partially for a carbon black, and 2.0-5.0pts.wt. of the foaming agent, wherein the foaming agent is a sulfonyl compound having a decomposition temperature of 143-147deg.C, a gas generating amount of 100-110ml/gr, and an average particle size of 3.0-4.0 micrometer.

Description

Tread Rubber Composition for Snow Tires

The present invention is a tread rubber composition for snow tires, and more specifically, for a snow tire including a suitable amount of a blowing agent in order to maximize driving and braking power on ice and snow roads and wet road surfaces in a tread rubber composition for silica with snow as a filler. It relates to a tread rubber composition.

Conventional winter snow tires are roughly classified into spike tires and studless tires. Among them, the spike tire utilizes the principle of increasing friction between the tire and the snow surface by providing rubber spike pins to increase the driving and braking force on the snow surface. Spike tires, however, are mostly used in extreme areas, and are often avoided due to problems such as noise on general roads. Currently, tires of studless tires are generally used.

However, the conventional studless snow tire is limited to mainly using carbon black as a filler or partially using silica as a filler, but these configurations alone have many limitations in maximizing driving and braking performance on winter snow.

The present invention has been made to solve the problems of the conventional snow tires as described above to replace all or part of the silica in the tread rubber composition, and by adding an appropriate amount of blowing agent to the tread for snow tires to maximize the performance on the snow surface The purpose is to provide a rubber composition.

The present invention is a tread rubber for snow tires, wherein silica is applied by replacing all or part of carbon black with a filler in raw rubber mixed with natural rubber and synthetic rubber in a ratio of 3: 7 to 5: 5, and other known additives. The composition includes a tread rubber composition for a snow tire comprising 2.0 to 5.0 parts by weight of a blowing agent to maximize driving force and braking force on a snowy road surface and a wet road surface.

The raw material rubber is a mixed rubber generally applied to a tread for snow tires, and natural rubber and synthetic rubber are preferably used in a ratio of 3: 7 to 5: 5. As the synthetic rubber, for example, polystyrene-butadiene rubber, polybutadiene rubber, or the like may be used alone or in combination.

As a filler, a mixed form may be used in which carbon black is replaced by a whole amount of silica or partially substituted. The carbon black usable in the present invention does not require any particular limitation. For example, the carbon black can be sufficiently implemented to satisfy the conditions of 82 to 119 mg / cc of iodine value and 102 to 125 cm 3/100 g of DBP oil absorption.

In addition, silica (SiO _2-n H ₂ O, _n ≦ 0.008) to be added is not limited to a particular kind, for example, it satisfies the condition that the CTAB value is 150 to 180 m 2 / g and the BET surface area is 150 to 200 m 2. It is enough to implement the present invention.

The content of carbon black and silica as the filler is configured as a known composition ratio. Therefore, the carbon black may be in the range of 0 to 60 parts by weight and silica in the range of 20 to 80 parts by weight, but is not necessarily limited to the above range.

The blowing agent is added to maximize the driving force and braking force on the ice and wet road surface of the rubber composition to which silica is applied. At this time, examples of the blowing agent that can be added include a sulfonyl compound, and the sulfonyl compound has an appropriate foam size (particle size) in order to optimize snow performance and adaptation on a general road surface. It is more preferred in the practice of the present invention to select from compounds which satisfy the conditions of 147 DEG C, gas generation amount of 100 to 110 ml / gr and average particle size of 3.0 to 4.0 mu m.

The blowing agent is preferably added 2.0 to 5.0 parts by weight to the rubber composition. If it is added less than 2.0 parts by weight it is difficult to expect the desired foaming effect, when exceeding 5.0 parts by weight may adversely affect the tire due to excessive foaming.

As an example of the specific compound which satisfy | fills the above conditions, the P, P'- oxybis (benzene sulfonyl hydrazide) type compound represented by the following structural formula is mentioned.

Other components included in the tread rubber composition of the present invention, for example, coupling agents, zinc oxide, stearic acid, antioxidants, waxes, sulfur, vulcanization accelerators, process oils and the like are suitable according to the range of addition amount known as known additives. Since it is enough to select and implement, detailed description about these is abbreviate | omitted.

Hereinafter, the contents of the present invention will be described in detail through 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.

Comparative Example 1

40 parts by weight of natural rubber, 40 parts by weight of polystyrene-butadiene rubber and 100 parts by weight of mixed rubber of 20 parts by weight of butadiene rubber, as shown in Table 1, 80 parts by weight of carbon black, 26 parts by weight of process oil, zinc oxide 3 By weight, 2 parts by weight of stearic acid, 3 parts by weight of antioxidant, 1 part by weight of wax, 2.5 parts by weight of sulfur, 1.5 parts by weight of vulcanization accelerator were added to the Banbury mixer and discharged at a temperature of 160 ° C.

Physical properties of the rubber were measured using ASTM test and Instron apparatus, and the average bubble diameter and foam density were measured by SEM tester and the results are shown in Table 2.

<Example 1>

60 parts by weight of carbon black, 20 parts by weight of silica, and a coupling agent (sulfide) based on 40 parts by weight of natural rubber, 40 parts by weight of polystyrene-butadiene rubber, and 100 parts by weight of mixed rubber of 20 parts by weight of butadiene rubber, as shown in Table 1 below. Silane (SI-69) and carbon black (N330) mixed at 50:50: X50S (trade name) 3.2 parts by weight, process oil 26 parts by weight, zinc oxide 3 parts by weight, stearic acid 2 parts by weight, antioxidant 3 parts by weight , 1 part by weight of wax, 2.7 parts by weight of sulfur, 1.5 parts by weight of vulcanization accelerator and 3.5 parts by weight of benzenesulfonylhydrazide (Unicell-BHS, manufactured by Dongjin Semichem) as a blowing agent were added to the Banbury mixer and released at a temperature of 160 ° C. .

Physical properties of the rubber were measured using ASTM test and Instron apparatus, and the average bubble diameter and foam density were measured by SEM tester and the results are shown in Table 2.

<Example 2>

It carried out under the same conditions as in Example 1 except adding 40 parts by weight of carbon black, 40 parts by weight of silica, and 4.8 parts by weight of coupling agent.

<Example 3>

It carried out under the same conditions as in Example 1 except adding 20 parts by weight of carbon black, 60 parts by weight of silica, and 7.2 parts by weight of coupling agent.

<Example 4>

It carried out under the same conditions as in Example 1 except adding 0 parts by weight of carbon black, 80 parts by weight of silica, and 12.8 parts by weight of coupling agent.

Example 5

It carried out under the same conditions as in Example 1 except adding 2.0 parts by weight of blowing agent.

<Example 6>

It carried out under the same conditions as in Example 1 except adding 5.0 parts by weight of the blowing agent.

<Table 1> Rubber Blend (Unit: parts by weight)

division Comparative example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Natural rubber ¹⁾ 40 40 40 40 40 40 40 SBR ²⁾ 40 40 40 40 40 40 40 BR ³⁾ 20 20 20 20 20 20 20 Carbon black 80 60 40 20 - 60 60 Silica - 20 40 60 80 20 20 Coupling agent - 3.2 4.8 7.2 12.8 3.2 3.2 Process oil 26 26 26 26 26 26 26 Zinc oxide 3 3 3 3 3 3 3 Stearic acid 2 2 2 2 2 2 2 Anti-aging 3 3 3 3 3 3 3 Wax One One One One One One One brimstone 2.5 2.7 2.7 2.7 2.7 2.7 2.7 Vulcanization accelerator 1.5 1.5 1.5 1.5 1.5 1.5 1.5 blowing agent - 3.5 3.5 3.5 3.5 2.0 5.0

1) Soviet Union or non-USSR natural rubber with less than 0.1% of pollutants

2) Emulsion polymerization synthetic rubber with styrene content of 23.5%

3) Synthetic rubber with more than 94% sheath and glass transition temperature of -105 ℃

<Table 2> Property Measurement Results

Item Comparative example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Shore A 59 60 60 59 59 60 58 300% modulus (kg / ㎠) 88 87 86 86 87 87 81 Tensile Strength (kg / ㎠) 185 191 190 188 187 187 175 Elongation (%) 550 540 541 530 535 532 520 0 ℃ Tanδ 0.160 0.182 0.201 0.215 0.231 0.183 0.182 Average bubble diameter (㎛) - 71 72 70 71 72 73 Foam density (n / ㎠) - 9633 9605 9710 9694 8420 11250

<Test Example>

The rubber composition was extruded into a tread and applied to the same tire of the 205 / 65R14 standard to produce a tire for a passenger car. Indicated.

Performance test on ice snow road surface was evaluated at outside temperature -3.6 ~ -15.2 ℃, road surface temperature -3.9 ~ -12.0 ℃, and braking performance test was measured by braking distance during sudden braking while driving. Is the time taken from the standstill to reach the 20m distance and the maximum speed at this time.

Table 3 Performance Test Results

Item Comparative example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Rolling resistance 100 108 110 112 115 108 106 Braking performance 100 102 104 106 106 101 108 Acceleration performance 100 101 103 105 105 101 110

According to the results, it can be confirmed that the foamed rubber composition according to the present invention is superior to the conventional studless snow tires in terms of rotational resistance, braking performance, and acceleration performance.

The tread rubber composition for snow tires of the present invention can maximize the performance of snow tires to maximize vehicle safety on ice and snow roads.

In addition, a spike pin is installed in the groove of the tire to improve the braking force and driving performance on the surface of ice and snow, but it can be used as a stud type tire that generates noise and dust on the general road. It is effective to minimize dust and dust.

Claims (4)

In the tread rubber composition for snow tires, which is made by applying silica to the raw material rubber mixed with natural rubber and synthetic rubber in a ratio of 3: 7 to 5: 5, in which all or part of carbon black is used as a filler, and other known additives. , The rubber composition is a tread rubber composition for snow tires, characterized in that it comprises 2.0 to 5.0 parts by weight of a blowing agent. The tread rubber composition for a snow tire according to claim 1, wherein the blowing agent is a sulfonyl compound having a decomposition temperature of 143 to 147 캜, a gas generation amount of 100 to 110 ml / gr, and an average particle size of 3.0 to 4.0 µm. The tread rubber composition according to claim 2, wherein the sulfonyl compound is a P, P'-oxybis (benzene sulfonylhydrazide) compound represented by the following structural formula. The tread rubber composition for a snow tire according to claim 1, wherein the rubber composition has a bubble diameter of 55 to 85 µm and a foam density of 9,000 to 10,000 / cm 2.