KR20040091169A - The Side Wall Compound for Tire - Google Patents

Abstract

PURPOSE: A tire sidewall rubber composition is provided, to minimize the reduction of an antiozonant due to the natural cause such as rain and to delay the time of an antiozonant to be discharge to the surface by using silica together with carbon black, thereby improving ozone characteristics and fatigue characteristics. CONSTITUTION: The tire sidewall rubber composition comprises 100 parts by weight of a rubber comprising a natural rubber and a butadiene rubber; 45-50 parts by weight of carbon black as a reinforcing agent; 2.5-8 parts by weight of silica; 0.4-1.2 parts by weight of a silica binder; 0.5-2 parts by weight of an antioxidant; and 2-5 parts by weight of an antiozonant. Preferably the carbon black has an iodine number of 64-70 m2/g and a DBP of 115-225 m2/100 g; the silica has a surface area of 150-190 m2/g, a CTAB of 150-180 m2/g and a pH of 6.5-7.5.

Description

Tire Sidewall Rubber Composition {The Side Wall Compound for Tire}

The present invention relates to a sidewall rubber composition of a tire for truck buses, and to a sidewall rubber composition having improved ozone and fatigue characteristics by using silica together with carbon black used as a reinforcing agent in the sidewall rubber composition.

The sidewall rubber composition of the tire for truck buses must be resistant to weather, ozone and the like, and it is also designed to resist tearing and cracking, and to be able to sustain heavy loads. It is designed to have fatigue characteristics. To increase resistance to tearing and cracking, natural rubber, butadiene rubber, or mixed rubber thereof is used, and various antioxidants and ozone inhibitors are used to have excellent resistance to ozone and climate. However, the amount of antioxidants and ozone inhibitors decreases continuously due to reaction with ozone on the surface of the sidewall and surface cleaning due to external environmental factors such as rain. However, ozone inhibitors used in rubber compositions have a disadvantage of discoloring the surface of tires when the amount of the coloring material is high.

The purpose of the present invention is to use the carbon black used as a reinforcement material of the sidewall rubber composition, silica, and the like due to the strong binding force due to the interaction of the functional group (NH) of the ozone inhibitor and the silano group on the silica surface, etc. Side effects that minimize the reduction of ozone inhibitors due to natural factors and delay the release time of ozone inhibitors to the surface, improve the performance for long-term ozone resistance, thereby improving tire durability To provide a monthly rubber composition.

The sidewall rubber composition of the tire of the present invention is characterized in that a natural rubber and butadiene rubber are used as a raw material rubber, and carbon black and silica are included together with a silica binder as a reinforcing agent.

In the sidewall rubber composition of the present invention, the mixing ratio of natural rubber and butadiene rubber used as the raw material rubber is not particularly limited, but is preferably blended in the range of 30 to 70/70 to 30.

In the sidewall rubber composition of the present invention, the carbon black used as one of the reinforcing agents is preferably carbon black having 64 to 70 m ₂ / g of I ₂ No and 115 to 225 m 2/100 g of DBP, and the amount of the raw material is rubber It is preferable that it is 45-50 weight part with respect to 100 weight part.

Sidewall rubber compositions require good tensile properties to resist fatigue and tearing, which can be achieved by adding reinforcing agents to the rubber composition. If the amount of the carbon black used as the reinforcing agent in the present invention is less than 45 parts by weight, the effect of improving tensile properties is insufficient, and if it exceeds 50 parts by weight, dispersibility and miscibility with the rubber component and other components may be deteriorated. In addition, when I ₂ No of carbon black is 64 m ₂ / g and DBP is less than 115 m 2/100 g, it may cause excessive decrease in tensile properties, and I ₂ No may exceed 70 m 2 / g and DBP of 225 m 2/100 g. In this case, the tensile property is improved, but the fatigue property is deteriorated, which is not preferable.

In the sidewall rubber composition of the present invention, the silica used as another reinforcing agent is preferably silica having a surface area of 150 to 190 m 2 / g, a CTBA of 150 to 180 m 2 / g, and a pH of 6.5 to 7.5, and the amount of the silica used is 2.5. It is preferable that it is-8 weight part. If the amount of the silica used is less than 2.5 parts by weight, the tensile property is lowered, and if it exceeds 8 parts by weight, the fatigue characteristics deteriorate.

In addition, the sidewall rubber composition of the present invention contains 0.4 to 1.2 parts by weight of silica binder based on 100 parts by weight of the raw material rubber. There is no particular limitation on the type of silica binder, and for example, a 1: 1 mixture of bis (triethoxysilylpropyl) tetrasulfane and carbon black is preferable. Limiting the amount of silica binder used in the above range is adjusted to an appropriate level according to the amount of silica used.

The sidewall rubber composition of the present invention contains 0.5 to 2 parts by weight of an antioxidant and 2 to 5 parts by weight of an ozone inhibitor. As antioxidants and ozone inhibitors, conventional types may be used. As antioxidants, for example, 2,2,4-trimethyl-1,2-dihydroquinoline (2,2,4-trimethyl-1,2-dihydro quinolin), and the ozone inhibitor is N- (1,3-dimethylbutyl) -N'-phenyl-para-phenyleneamine (N- (1,3-dimethylbutyl) -N'-phenyl-para-phenyleneamine Is preferred. If the content of the antioxidant and the ozone inhibitor is outside the above range, there is a fear that undesirable effects on fatigue properties, tensile properties and ozone properties.

In addition to the above components, the sidewall rubber composition of the present invention includes additives commonly added to the sidewall rubber composition, for example, aromatic oils, stearic acid, waxes, pressure-sensitive adhesives, sulfur, vulcanization accelerators, retardants, zincation, etc., as process oils. Additives may be included in an appropriate amount, the type and the appropriate amount of these additives are known in the art.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples.

Examples and Comparative Examples

Comparative Example 1

Using natural rubber and butadiene rubber as a main raw material, using only 50 parts by weight of carbon black as a reinforcing agent, a tire sidewall rubber composition was prepared according to the composition shown in Comparative Example 1 of Table 1. After preparing rubber specimens from this rubber composition, the physical properties were measured according to ASTM-related regulations, and the results are shown in Table 1.

Example 1

Tire sidewall rubber according to the composition shown in Example 1 of Table 1, using natural rubber and butadiene rubber as a main raw material, using 50 parts by weight of carbon black and 2.5 parts by weight of silica as a reinforcing agent, and 0.4 parts by weight of silica binder. The composition was prepared. After preparing rubber specimens from this rubber composition, the physical properties were measured according to ASTM-related regulations, and the results are shown in Table 1.

Example 2

Tire sidewall rubber according to the composition shown in Example 2 of Table 1, using natural rubber and butadiene rubber as the main raw materials, using 48 parts by weight of carbon black and 2.5 parts by weight of silica as a reinforcing agent, and 0.4 parts by weight of silica binder. The composition was prepared. After preparing rubber specimens from this rubber composition, the physical properties were measured according to ASTM-related regulations, and the results are shown in Table 1.

Example 3

Tire sidewall rubber according to the composition shown in Example 3 of Table 1, using natural rubber and butadiene rubber as the main raw materials, using 50 parts by weight of carbon black and 5.0 parts by weight of silica as the reinforcing agent, and 0.8 parts by weight of silica binder. The composition was prepared. After preparing rubber specimens from this rubber composition, the physical properties were measured according to ASTM-related regulations, and the results are shown in Table 1.

Example 4

Tire sidewall rubber according to the composition shown in Example 4 of Table 1, using natural rubber and butadiene rubber as a main raw material, using 45 parts by weight of carbon black and 5.0 parts by weight of silica as the reinforcing agent, and 0.8 parts by weight of silica binder. The composition was prepared. After preparing rubber specimens from this rubber composition, the physical properties were measured according to ASTM-related regulations, and the results are shown in Table 1.

Example 5

Tire sidewall rubber according to the composition shown in Example 5 of Table 1, using natural rubber and butadiene rubber as a main raw material, using 45 parts by weight of carbon black and 7.5 parts by weight of silica as a reinforcing agent, and 1.2 parts by weight of silica binder. The composition was prepared. After preparing rubber specimens from this rubber composition, the physical properties were measured according to ASTM-related regulations, and the results are shown in Table 1.

[Table 1] Sidewall rubber composition (unit: parts by weight) and physical properties

^* 1: Carbon black with 70 mg / g of I ₂ No and 225 ㎡ / 100g of DBP

^* 2: Silica having a surface area of 150 m 2 / g CTAB of 180 m 2 / g and pH 7.0

^* 3: 1: 1 mixture of Bis (triethoxysilylpropyl) tetrasulfane and carbon black

^* 4: 2,2,4-trimethyl-1,2-dihydro quinolin

^* 5: N- (1,3-dimethylbutyl) -N'-phenyl-para-phenyleneamine

^* Ozone characteristic test conditions are tested at a concentration of 50ppm ozone concentration after 20% tensile test of the specimen.

* The residual amount of ozone inhibitor is the result of chemical analysis after 100 days of test specimen.

As can be seen from the above examples and comparative examples, by using an appropriate amount of carbon black and silica together as a reinforcing agent of the sidewall rubber composition, and using an antioxidant and an ozone inhibitor, the vulcanization characteristics and tensile properties are not affected. Therefore, rubber compositions with excellent ozone and fatigue properties could be prepared by increasing the sustainability of ozone inhibitors.

Claims (2)

In the tire sidewall rubber composition, 45 to 50 parts by weight of carbon black, 2.5 to 8 parts by weight of silica, 0.4 to 1.2 parts by weight of silica binder, and antioxidant, based on 100 parts by weight of raw rubber composed of natural rubber and butadiene rubber. A tire sidewall rubber composition comprising 0.5 to 2 parts by weight and 2 to 5 parts by weight of an ozone inhibitor. The carbon black has I ₂ No of 64 to 70 m ₂ / g, DBP of 115 to 225 m 2/100 g, and the silica has a surface area of 150 to 190 m 2 / g and CTAB of 150 to 180 m 2 / g, pH 6.5-7.5 The tire sidewall rubber composition.