KR20130057854A - Rubber composition for tire tread and tire manufactured by using the same - Google Patents

Abstract

PURPOSE: A rubber composition for tire tread is provided to increase a frictional coefficient and to obtain excellent braking performance on an icy or wet road. CONSTITUTION: A rubber composition for tire tread comprises liquid polybutadiene rubber which includes 100.0 parts by weight of raw rubber, 5-10 parts by weight of a shell-crushed material, 1-5 parts by weight of a foaming agent, and 7-12 parts by weight of a siloxane group. The surface of the shell-crushed material is treated by a C15-20 organic material which includes a carboxylic acid group. The vinyl content of the liquid polybutadiene rubber is 5-30wt%. The mooney viscosity is 50-70 and the number average molecular weight is 2,000-3,000g/mol. The foaming agent is toluenesulfonyl hydrazide.

Description

TECHNICAL FIELD [0001] The present invention relates to a rubber composition for a tire tread, and a tire manufactured using the same. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a rubber composition for tire treads and a tire manufactured using the same, wherein the tire tread rubber can improve the ice sheet friction coefficient by using a liquid polybutadiene rubber including a surface-modified clam shell crush and siloxane groups. It relates to a composition.

In order to increase the driving force and the braking force of the tire, the conventional method employs the principle of increasing the friction between the tire and the snow surface by providing spike pins on the tread surface. However, spike tires are mainly used in extreme areas, and their use is regulated due to growing interest in the environment due to the problem of generating noise on the general road surface and generating dust by causing spikes to damage the road surface.

Conventional studless snow tires are also limited to the use of carbon black and silica as fillers, and therefore, there is a limit to maximizing driving and braking performance on winter snow.

In order to overcome these limitations, in order to improve braking performance on the ice surface of winter tires, a method of making foamed pores or injecting fiberglass into tread rubber has been studied. Porous pumice is applied.

However, when the foaming agent is added, when the pores are excessively formed inside the rubber due to foaming or when the hardened material does not play a role of the filler, the strength of the entire rubber is lowered, thereby reducing the wear performance of the tire.

The invention described in the prior patent document 1 (Publication No. 10-2007-0014518, publication date: February 01, 2007) is for reinforcing the spike effect of a tire using a shell shell crushed product. However, the clam pulverized product was only coupled using Si69 of Degussa Co., and oxybis benzene sulfonyl hydrazide was used as a blowing agent, resulting in uneven dispersion of the clam pulverized product. Since the binding force with the raw rubber is weak, the shell shell pulverization located on the surface of the tire tread portion may run off while driving. Accordingly, there is a problem that the life of the tire is also very short.

The invention described in the prior patent document 2 (registration number: 10-0764560, publication date: October 08, 2007) is for reinforcing the spike effect of a tire by using a blowing agent and nanoclair. However, the nanoclair has a plate-like structure, and has a disadvantage in that the spike effect is poor because the average particle diameter is too fine. Accordingly, there is a problem that the degree of improvement in ice friction coefficient is smaller than that of the present invention, and there is a limit in improving the braking property.

KR 10-2007-0014518 A KR 10-0764560 B1

An object of the present invention is to make the surface-modified clam pulverized to serve as a spike of the tire tread portion, to improve the dispersibility of the surface-modified clam pulverized, the bonding strength and reinforcement of the raw rubber. In addition, through this to improve the ice sheet friction coefficient of the tire tread rubber composition more remarkably, to provide a rubber composition for the tire tread having a longer life.

Another object of the present invention is to provide a tire produced by using the rubber composition for a tire tread.

In order to achieve the above object, the rubber composition for a tire tread according to an embodiment of the present invention is a liquid containing 100 parts by weight of the raw material rubber, 5 to 10 parts by weight of clam shell grinding, 1 to 5 parts by weight of blowing agent, and siloxane groups 7 to 12 parts by weight of polybutadiene rubber, and the shell shell pulverized is a surface-modified organic material having a carbon number of 15 to 20 containing a carboxylic acid group (carboxylic acid group) at the end.

The liquid polybutadiene rubber may have a vinyl content of 5 to 30 wt%, a Mooney viscosity (ML _{1 +4} , 100 ° C.) of 50 to 70, and a number average molecular weight of 2000 to 3000 g / mol.

The blowing agent may be toluenesulfonyl hydrazide.

The clam shell pulverized product may have an average particle diameter of 0.5 mm or less.

The surface-modified clamshell pulverized product may be one whose surface is modified with 1 to 4 parts by weight of the organic material based on 10 parts by weight of the clamshell pulverized product.

The organic material is oleic acid (oleic acid), linoleic acid (linoleic acid), lauric acid (lauric acid), pentadecylic acid (pentadecylic acid), margaric acid (Margaric acid), palmitic acid (palmitic acid), stearic acid (stearic) acid) and combinations thereof.

Tire according to another embodiment of the present invention is manufactured by using the rubber composition for the tire tread.

Hereinafter, the present invention will be described in more detail.

Tire tread rubber composition according to an embodiment of the present invention is 100 parts by weight of the raw material rubber, 5 to 10 parts by weight of clam shell mill, 1 to 5 parts by weight of the blowing agent, and 7 to 12 parts by weight of the liquid polybutadiene rubber The clam shell pulverized product is a surface-modified organic material having 15 to 20 carbon atoms including a carboxylic acid group at its end.

The raw material rubber may be any one selected from the group consisting of natural rubber, synthetic rubber, and combinations thereof.

The natural rubber may be a general natural rubber or a modified natural rubber.

The above-mentioned general natural rubber may be used as long as it is known as natural rubber, and the country of origin and the like are not limited. The natural rubber includes cis-1,4-polyisoprene as a main component, but may also include trans-1,4-polyisoprene depending on required characteristics. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main component, natural rubber including trans-1,4-isoprene as a main component, such as balata, Rubber may also be included.

The modified natural rubber means that the general natural rubber is modified or purified. For example, examples of the modified natural rubber include epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber.

Synthetic rubber is styrene butadiene rubber (SBR), modified styrene butadiene rubber, butadiene rubber (BR), modified butadiene rubber, chloro sulfonated polyethylene rubber, epichlorohydrin rubber, fluorine rubber, silicone rubber, nitrile rubber, hydrogenated Nitrile Rubber, Nitrile Butadiene Rubber (NBR), Modified Nitrile Butadiene Rubber, Chlorinated Polyethylene Rubber, Styrene Ethylene Butylene Styrene (SEBS) Rubber, Ethylene Propylene Rubber, Ethylene Propylene Diene (EPDM) Rubber, Hypalon Rubber, Chloroprene Rubber, Ethylene vinyl acetate rubber, acrylic rubber, hydrin rubber, vinyl benzyl chloride styrene butadiene rubber, bromo methyl styrene butyl rubber, maleic acid styrene butadiene rubber, carboxylic acid styrene butadiene rubber, epoxy isoprene rubber, maleic acid ethylene propylene rubber, carboxylic acid Nitrile Butadiene High It may be a p-methyl styrene (brominated polyisobutyl isoprene-co-paramethyl styrene, BIMS), and one selected from the group consisting of -, bromo mineyi suited polyisobutyl isoprene-co.

The clam shell pulverization is included in 5 to 10 parts by weight based on 100 parts by weight of the raw material rubber. If the content of the clam shell crushing is less than 5 parts by weight, the effect of the role of spike on the worn surface of the tread can not be obtained, if there is more than 10 parts by weight there is a problem that the tensile strength is sharply lowered.

The clam shell pulverized product is surface modified with an organic material having 15 to 20 carbon atoms including a carboxylic acid group at its end.

In the case of modifying the surface of the clam shell crushed by the organic material, there is an advantage that the dispersion is advantageous in one rubber compound. The organic material is specifically oleic acid (oleic acid), linoleic acid (linoleic acid), lauric acid (lauric acid), pentadecyllic acid (pentadecylic acid), margaric acid (Margaric acid), palmitic acid (palmitic acid), stearic acid (stearic acid) and combinations thereof, any one selected from the group may be used, and stearic acid may be preferably used. When the surface of the clam pulverized product is modified with stearic acid, the affinity with rubber is further increased, thereby showing better binding force with other rubber composition components and improving dispersibility.

The surface-modified clamshell pulverized product may be surface-modified with 1 to 4 parts by weight of the organic material based on 10 parts by weight of the clamshell pulverized product. When the content of the organic matter is less than 1 part by weight, there is almost no effect of increasing affinity with rubber due to surface modification, and when it exceeds 4 parts by weight, the spike effect of the surface-modified clam shell grind may be inhibited.

The clam shell pulverized product may have an average particle diameter of 0.5 mm or less, preferably 0.3 nm to 0.5 mm. When the average particle diameter of the clam shell pulverization is within the above range, there is an advantage that the strength of the rubber is not lowered. If the average particle diameter of the shell shell pulverization is greater than 0.5mm, there is a problem that the tire wear performance is sharply lowered due to a sharp decrease in tensile strength.

The tire tread rubber composition modifies the clam shell crushed product with an organic material so that the clam crushed product does not fall out of the rubber to maintain the strength of the rubber composition before the tread is worn, and when the tread is worn, clam shell crushed Water can act as a spike on the tire surface, significantly improving the ice sheet friction coefficient. In addition, the rubber composition for the tire tread by using a shell material crushed environmentally friendly material, there is no fear of causing environmental harmful substances when the tire wear.

The blowing agent is included in 1 to 5 parts by weight based on 100 parts by weight of the raw material rubber. The blowing agent is for improving the braking property on snow or ice, and when the content of the blowing agent is less than 1 part by weight, foaming is too small to obtain the effect of removing water film due to foaming. There is a problem in that the rubber properties decrease sharply.

As the blowing agent, a general blowing agent including oxybis benzene sulfonyl hydrazide may be used, but toluenesulfonyl hydrazide may be preferably used. The toluene sulfonyl hydrazide is much more excellent in braking performance than oxybis benzene sulfonyl hydrazide because of its uniform foam form.

The liquid polybutadiene rubber including the siloxane group is included in an amount of 7 to 12 parts by weight based on 100 parts by weight of the raw material rubber.

Since the siloxane group is located at the molecular end of the polybutadiene rubber, the liquid polybutadiene rubber including the siloxane group improves the dispersibility of the clam shell mill and the silica whose surface is modified, and the affinity of the filler to the raw material rubber. Enhancement to improve tire braking

When the liquid polybutadiene rubber including the siloxane group is included in less than 7 parts by weight based on 100 parts by weight of the raw material rubber, the surface-modified clam shell pulverized product and silica do not exhibit a dispersibility effect, and there is little improvement in braking performance. . In addition, since it is difficult to maintain the physical properties of the rubber when included in excess of 12 parts by weight, the wear resistance of the rubber is deteriorated, thereby causing a problem that the braking property is rather reduced.

The liquid polybutadiene rubber including the siloxane group may have a vinyl content of 5 to 30 wt%, a Mooney viscosity of 50 to 70, and a number average molecular weight of 2000 to 3000 g / mol. In addition, the vinyl content is preferably 10 to 20% by weight, a Mooney viscosity of 50 to 60, a number average molecular weight of 2200 to 2800g / mol can be used.

When the vinyl content of the liquid polybutadiene rubber is less than 5% by weight, there is a problem of low reactivity with shellfish and silica, and when it exceeds 30% by weight, it is difficult to maintain physical properties. When the Mooney viscosity of the liquid polybutadiene rubber is less than 50, the stress required for dispersion is reduced during the mixing process, which causes disadvantageous filter dispersion, and when the Mooney viscosity exceeds 70, mixing of rubbers is disadvantageous and filter dispersion is performed. Problem occurs. In addition, when the number average molecular weight of the liquid polybutadiene rubber is less than 2200 g / mol, a problem of poor wear occurs, when the exceeds 2800 g / mol occurs a workability problem.

The tire tread rubber composition may optionally further include various additives such as additional vulcanizing agents, vulcanization accelerators, fillers, coupling agents, anti-aging agents, softeners, and the like. The various additives can be used as long as it is commonly used in the field of the present invention, the content thereof is not particularly limited, depending on the compounding ratio used in the conventional tire tread rubber composition.

As said vulcanizing agent, a sulfur type vulcanizing agent can be used preferably. The sulfur-based vulcanizing agent may be inorganic vulcanizing agents such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S), colloidal sulfur (colloid sulfur). Specifically, as the sulfur vulcanizing agent, a vulcanizing agent which produces elemental sulfur or sulfur, for example, amine disulfide, polymer sulfur, or the like can be used.

The vulcanizing agent is preferably included in an amount of 0.5 to 4.0 parts by weight based on 100 parts by weight of the raw material rubber, in that the raw material rubber is less sensitive to heat and chemically stable.

The vulcanization accelerator refers to an accelerator that promotes the rate of vulcanization or promotes delay in the initial vulcanization stage. The vulcanization accelerator may be included in an amount of 0.5 to 4.0 parts by weight based on 100 parts by weight of the raw material rubber in order to maximize productivity and rubber properties by promoting the vulcanization rate.

The tire tread rubber composition may further include a filler. The filler may be any one selected from the group consisting of carbon black, silica, calcium carbonate, clay (hydrated aluminum silicate), aluminum hydroxide, lignin, silicate, talc, and combinations thereof.

The carbon black may have a nitrogen surface area per gram (N ₂ SA) of 30 to 300 m ² / g and an oil absorption amount of DBP (n-dibutyl phthalate) of 60 to 180 cc / 100 g, But is not limited thereto.

If the nitrogen adsorption specific surface area of the carbon black exceeds 300 m ² / g, the workability of the rubber composition for a tire may be deteriorated. If it is less than 30 m ² / g, the reinforcing performance by carbon black as a filler may be deteriorated. If the DBP oil absorption of the carbon black exceeds 180 cc / 100 g, the workability of the rubber composition may be deteriorated. If it is less than 60 cc / 100 g, the reinforcing performance by carbon black as a filler may be deteriorated.

Examples of the carbon black include N110, N121, N134, N220, N231, N234, N242, N293, N299, S315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 or N991.

The carbon black may be included in an amount of 30 to 80 parts by weight based on 100 parts by weight of the raw material rubber, preferably 45 to 65 parts by weight, and more preferably 53 to 57 parts by weight. When the content of the carbon black is less than 30 parts by weight, the reinforcing performance by the carbon black as a filler may decrease, and when the content of the carbon black exceeds 80 parts by weight, the processability of the rubber composition may be deteriorated.

The silica may have a nitrogen surface area per gram (N ₂ SA) of 100 to 180 m ₂ / g and a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 110 to 170 m 2 / g. But is not limited thereto.

If the nitrogen adsorption specific surface area of the silica is less than 100 m < 2 > / g, the reinforcing performance by the silica as the filler may be deteriorated. If it exceeds 180 m2 / g, the workability of the rubber composition may be deteriorated. If the CTAB adsorption specific surface area of the silica is less than 110 m < 2 > / g, the reinforcing performance by silica as a filler may be deteriorated.

Ultrasil VN2 (manufactured by Degussa AG), Ultrasil VN3 (manufactured by Degussa AG), Z1165MP (manufactured by Rhodia) or Z165GR (manufactured by Rhodia) can be used as the commercially available products. .

The silica may be contained in an amount of 20 to 90 parts by weight based on 100 parts by weight of the raw rubber, more preferably 30 to 70 parts by weight, and further preferably 40 to 60 parts by weight. If the content of the silica is less than 20 parts by weight, the strength of the rubber may not be improved and the braking performance of the tire may be deteriorated. If the content of the silica exceeds 90 parts by weight, the wear performance may be deteriorated.

Examples of the coupling agent include a sulfide-based silane compound, a mercapto-based silane compound, a vinyl-based silane compound, an amino-based silane compound, a glycidoxine clock silane compound, a nitro- based silane compound, a chlorosilicate compound, a methacrylic silane compound, May be used, and a sulfide-based silane compound may be preferably used.

The sulfide-based silane compound is preferably selected from the group consisting of bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (4-trimethoxysilylbutyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis Bis (3-trimethoxysilylethyl) trisulfide, bis (4-triethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis (3-triethoxysilylbutyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis 3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxy Triethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethyl 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilyl 3-trimethoxysilylpropylmethacrylate monosulfide, 3-trimethoxysilylpropylmethacrylate monosulfide, and combinations thereof may be used in combination with at least one compound selected from the group consisting of benzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-trimethoxysilylpropylmethacrylate monosulfide, And the like.

The mercaptosilane compound may be at least one selected from the group consisting of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, May be any one selected from the group consisting of The vinyl-based silane compound may be any one selected from the group consisting of ethoxysilane, vinyltrimethoxysilane, and combinations thereof. The amino-based silane compound is preferably selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- Methoxysilane, and a combination thereof.

The glycidoxime silane compound is preferably selected from the group consisting of? -Glycidoxypropyltriethoxysilane,? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropylmethyldiethoxysilane,? -Glycidoxypropylmethyldimethoxysilane And a combination thereof. The nitro-based silane compound may be any one selected from the group consisting of 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, and combinations thereof. The chloro-based silane compound is selected from the group consisting of 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, and combinations thereof Lt; / RTI >

The methacrylic silane compound is any one selected from the group consisting of γ-methacryloxypropyl trimethoxysilane, γ-methacryloxypropyl methyldimethoxysilane, γ-methacryloxypropyl dimethyl methoxysilane, and combinations thereof Can be.

The coupling agent may be included in an amount of 1 to 20 parts by weight based on 100 parts by weight of the raw rubber for improving dispersibility of the silica. If the content of the coupling agent is less than 1 part by weight, improvement in dispersibility of silica may be insufficient, resulting in deterioration of rubber workability and lowering of fuel consumption performance. When the amount exceeds 20 parts by weight, interaction between silica and rubber is too strong, May be excellent, but the braking performance may be very poor.

The softener is added to the rubber composition to impart plasticity to the rubber to facilitate processing or to lower the hardness of the vulcanized rubber, and refers to oils and other materials used in rubber compounding or rubber production. The softener refers to oils included in process oil or other rubber compositions. The softener may be any one selected from the group consisting of petroleum oil, vegetable oil and combinations thereof, but the present invention is not limited thereto.

The petroleum oil may be any one selected from the group consisting of paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof.

Representative examples of the paraffinic oil include P-1, P-2, P-3, P-4, P-5, and P-6 of Michang Oil, Inc. A representative example of the naphthenic oil is Michang oil. N-1, N-2, N-3, etc. of the corporation | Co., Ltd. are mentioned, As a representative example of the said aromatic oil, A-2, A-3, etc. of Michang Oil Corporation are mentioned.

However, recently, when the content of the polycyclic aromatic hydrocarbons (hereinafter referred to as PAHs) contained in the aromatic oil is higher than 3 wt% together with the increase of the environmental consciousness, treated distillate aromatic extract oil, mild extraction solvate (MES) oil, residual aromatic extract (RAE) oil or heavy naphthenic oil.

In particular, the oil used as the softener has a total content of PAHs component of 3% by weight or less, a kinematic viscosity of 95 or more (210 ° F SUS), an aromatic component in the softener of 15 to 25% by weight, and a naphthenic component TDAE oils having 27 to 37% by weight and 38 to 58% by weight of the paraffinic component can be preferably used.

The TDAE oil is advantageous for environmental factors such as the low temperature characteristics of the tire tread including the TDAE oil and the possibility of the cancer induction of PAHs while improving the fuel consumption performance.

The plant oils include castor oil, cottonseed oil, linseed oil, canola oil, soybean oil, palm oil, palm oil, peanut oil, pine oil, pine tar, tall oil, corn oil, rice bran oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil It may be used any one selected from the group consisting of jojoba oil, macadamia nut oil, saflower flower oil, tung oil and combinations thereof.

The softening agent is preferably used in an amount of 0 to 150 parts by weight based on 100 parts by weight of the raw material rubber, in terms of improving the processability of the raw material rubber.

The anti-aging agent is an additive used to stop the chain reaction in which the tire is automatically oxidized by oxygen. As the anti-aging agent, any one selected from the group consisting of an amine type, a phenol type, a quinoline type, an imidazole type, a carbamic acid metal salt, a wax and a combination thereof can be appropriately selected and used.

Examples of the amine type antioxidant include N-phenyl-N '- (1,3-dimethyl) -p-phenylenediamine, N- (1,3-dimethylbutyl) -N'- Phenyl-N'-isopropyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, -Cyclohexyl p-phenylenediamine, N-phenyl-N'-octyl-p-phenylenediamine, and combinations thereof. Examples of the phenolic antioxidant include phenol-based 2,2'-methylene-bis (4-methyl-6-tert-butylphenol), 2,2'- isobutylidene- Di-t-butyl-p-cresol, and combinations thereof. As the quinoline antioxidant, 2,2,4-trimethyl-1,2-dihydroquinoline and its derivatives can be used. Specifically, 6-ethoxy-2,2,4-trimethyl- Dihydroquinoline, 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline and combinations thereof Any one selected from the group can be used. As the wax, waxy hydrocarbons can be preferably used.

The anti-aging agent has a high solubility in rubber in addition to the anti-aging action, is low in volatility, inert to rubber, and does not inhibit vulcanization. It may be included in parts by weight.

A tire according to another embodiment of the present invention is manufactured using the rubber tread rubber composition. The method of manufacturing a tire using the tire tread rubber composition may be applied to any method conventionally used for the production of tires, and thus, detailed description thereof will be omitted.

The rubber composition for tire treads of the present invention not only improves the affinity and dispersibility of the siloxane group of the liquid rubber, but also the affinity and dispersibility of the clam shell pulverized product and the foaming agent whose surface is modified with an organic material containing carboxylic acid. To improve.

Thus, with a stronger spike effect on the ground, the coefficient of ice friction on ice and wet road surfaces can be increased. In addition, the rubber composition for tire treads has much better braking performance on ice and wet roads than when only the shell shell pulverized product was included.

The surface modification of the clam shell mill and the siloxane groups of the liquid polybutadiene result in a very strong bonding force between the clam shell mill and the raw material rubber whose surface is contained in the tire tread. Therefore, there is no problem that the surface-modified clam pulverized product located on the tire tread portion falls off while driving, and thus, the life of the tire is very long.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[ Manufacturing example : Preparation of Rubber Composition]

Using the composition shown in Table 1 below to prepare a rubber composition for tire treads according to Examples 1 to 4 and Comparative Examples 1 to 4. The rubber composition was prepared according to a conventional method for preparing a rubber composition.

division Example 1 Example 2 Example 3 Example
4 Comparative Example
One Comparative Example 2 Comparative Example 3 Comparative Example 4 Rubber material ¹⁾ 100 100 100 100 100 100 100 100 Clamshell ^{2 )} 7 7 7 7 - 12 7 7 Blowing agent A ³⁾ 4 4 4 - - - 4 4 Blowing agent B ⁴⁾ - - - 4 - - - - Liquid Polybutadiene Rubber ⁵⁾ 7 10 12 10 - - - 15 Silica 70 70 70 70 70 70 70 70 Aromatic Oil ^{6 )} 12 12 12 12 12 12 12 12 Zinc oxide 4 4 4 4 4 4 4 4 Stearic acid 2 2 2 2 2 2 2 2 Antioxidant ^{7 )} 2 2 2 2 2 2 2 2 Wax 2 2 2 2 2 2 2 2 brimstone 2 2 2 2 2 2 2 2

(Unit: parts by weight)

1) Raw material rubber: 70 parts by weight of natural rubber, 30 parts by weight of 1,4-cispolybutadiene rubber

2) Clamshell Grinding: Clamshell grinding powder having an average particle diameter of 0.45 mm or less subjected to surface modification with stearic acid (the surface is modified with 2 parts by weight of stearic acid per 10 parts by weight of clamshell grinding)

3) Blowing agent A: toluenesulfonyl hydrazide

4) Blowing agent B: Oxybis benzene sulfonyl hydrazide

5) Liquid polybutadiene rubber: Liquid polybutadiene rubber containing siloxane group, vinyl content of 20% by weight, Mooney viscosity 60, number average molecular weight 2200 g / mol

6) Aromatic Oil: Michang Petroleum Industries, A # 2 Oil

7) Antioxidant: Kumho Petrochemical, KUMANOX-13

[ Experimental Example : Measurement of physical properties of the manufactured rubber composition]

The physical properties of the rubber specimens were measured by the following measuring methods, and the results are shown in Table 2 below.

(1) Tensile Properties: It was measured according to ASTM D412 test method using an Instron tester.

(2) Friction Coefficient: As a result of measuring friction coefficients on ice and wet roads using a Dynamic Friction Tester, Comparative Example 1 was expressed as 100 based on this. Ice friction performance is better the higher the value.

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Seal
Properties Hardness 57 58 58 57 56 55 56 54 300% modulus (kgf / cm ² ) 102 108 110 85 90 83 92 87 friction
Coefficient Ice road surface 122 128 130 110 100 103 105 98 Wet road 105 107 111 108 100 102 104 100

As shown in Table 2, Examples 1 to 4 are examples of the case where the surface-modified clamshell pulverized with stearic acid and a liquid polybutadiene rubber including a siloxane group are included, and the comparative example does not include the liquid polybutadiene rubber. Compared with 3, the coefficient of friction on wet roads is somewhat increased, especially on ice roads. That is, it was found that the braking force on the ice road surface was greatly improved when the surface-modified clam shell pulverized product contained the liquid polybutadiene rubber including the siloxane group.

In Examples 1 to 3, when toluene sulfonyl hydrazide was used as a blowing agent, it was confirmed that friction coefficients on ice and wet roads were improved compared to Example 4 using oxybis benzene sulfonyl hydrazide as a blowing agent. have. That is, when using the toluene sulfonyl hydrazide it was found that the foaming has an even form, thereby improving the braking force.

Comparative Example 1 did not include the liquid polybutadiene rubber containing clam shell mill, foaming agent, and siloxane group, and had the lowest coefficient of friction on ice and wet road surfaces.

Comparative Example 2 is a case in which 12 parts by weight of the clamshell crushed product is further included in Comparative Example 1, and the coefficient of friction on ice and wet road surface was slightly increased compared to Comparative Example 1. However, as compared with Examples 1 and 4, the coefficient of friction on ice and wet roads was greatly reduced, and it was confirmed that braking performance was very poor.

Comparative Example 4 is a case in which the liquid polybutadiene rubber containing the siloxane group exceeds 12 parts by weight with respect to the raw material rubber, and it can be seen that the braking property is lowered when the Comparative Example 4 is compared with Examples 1 to 4 above. there was. Therefore, as in Examples 1 to 4, when the content of the liquid polybutadiene limited in the present invention, the friction coefficient on ice and wet road surface was confirmed that the braking property is better.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (7)

100 parts by weight of raw rubber,
5 to 10 parts by weight of clam shell mill,
1 to 5 parts by weight of blowing agent, and
7 to 12 parts by weight of a liquid polybutadiene rubber including siloxane groups,
The clam shell pulverized product is a surface-modified organic material having a carbon number of 15 to 20 containing a carboxylic acid group (carboxylic acid group) at the end
Rubber composition for tire tread. The method of claim 1,
The liquid polybutadiene rubber has a vinyl content of 5 to 30% by weight, a Mooney viscosity of 50 to 70, and a number average molecular weight of 2000 to 3000 g / mol. The method of claim 1,
Wherein the foaming agent is toluenesulfonyl hydrazide. 2. The rubber composition for tire tread according to claim 1, wherein the foaming agent is toluenesulfonyl hydrazide. The method of claim 1,
The clam shell pulverized product is a rubber composition for tire tread having an average particle diameter of 0.5 mm or less. The method of claim 1,
The surface-modified clamshell pulverized product is a rubber composition for tire treads whose surface is modified with 1 to 4 parts by weight of the organic material based on 10 parts by weight of the clamshell pulverized product. The method of claim 1,
The organic material is oleic acid (oleic acid), linoleic acid (linoleic acid), lauric acid (lauric acid), pentadecylic acid (pentadecylic acid), margaric acid (Margaric acid), palmitic acid (palmitic acid), stearic acid (stearic) acid) and any one selected from the group consisting of a rubber composition for tire treads. A tire manufactured using the rubber composition for tire tread according to any one of claims 1 to 6.