KR20200058210A - Rubber composition for tire tread and tire manufactured by using the same - Google Patents

Abstract

The present invention relates to a rubber composition for a tire tread and a tire manufactured by using the same. The rubber composition for the tire tread comprises: 100 parts by weight of raw material rubber containing 30 to 60 parts by weight of emulsion-polymerized styrene butadiene rubber; 90 to 140 parts by weight of a reinforcing filler containing silica; 5 to 30 parts by weight of natural oil; and 10 to 30 parts by weight of aromatic resin. The rubber composition for the tire tread can maximize a wet grip performance and a wear performance, which have a trade-off relationship with each other, while maintaining a balance between all the performances to be suitable for four-season compound properties.

Description

Rubber composition for tire tread and tire manufactured using the same {RUBBER COMPOSITION FOR TIRE TREAD AND TIRE MANUFACTURED BY USING THE SAME}

The present invention relates to a rubber composition for a tire tread and a tire manufactured using the same, and more specifically, a wet grip having a trade-off relationship while all performances are balanced in accordance with compound properties for all seasons ( It is to provide a rubber composition for a tire tread capable of maximizing wet grip performance and abrasion performance and a tire manufactured using the same.

Due to the development of tire technology, tires have been developed and released for each season and use conditions, such as summer tires, winter tires, and all season tires.

Particularly, in the case of the tire for four seasons, it is important to balance in all performance aspects because it exhibits the intermediate property of the summer tire and the performance of the winter tire.

In addition, in view of the current trend of vehicles with tires for four seasons, the demand for SUVs is increasing, and as electric vehicles equipped with batteries are newly developed, the weight of the entire vehicle is increasing.

Accordingly, as the trend of the demand vehicle changes, the conditions required for the tires for all seasons are becoming more severe than before. In particular, as mentioned above, as the weight of the vehicle increases, the importance of tire wear is becoming more important, and the wet and dry braking (Wet / Dry) braking parts are also used to satisfy the market's required performance. The pounding technique needs to be further developed.

An object of the present invention is to provide a rubber composition for tire treads that can maximize wet grip performance and wear performance in a trade-off relationship, while all performances are balanced according to the compound characteristics for all seasons. Is to provide.

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

According to one embodiment of the present invention, emulsion polymerized styrene-butadiene rubber (Emulsion-polymerized Styrene Butadiene Rubber) 100 parts by weight of raw rubber comprising 30 parts by weight to 60 parts by weight, 90 parts by weight to 90 parts by weight of a reinforcing filler comprising silica Provided is a rubber composition for tire treads comprising 5 parts by weight to 30 parts by weight of natural oil, and 10 parts by weight to 30 parts by weight of an aromatic resin.

The emulsion polymerized styrene-butadiene rubber may have a weight average molecular weight of 1,000,000 g / mol to 2,500,000 g / mol, and a glass transition temperature (T _g ) of -35 ° C to -60 ° C.

The raw rubber may further include 20 parts by weight to 40 parts by weight of butadiene rubber having a cis content of 95% by weight or more.

The natural oil is 15 to 30% by weight of oleic acid (Oleic acid), 40 to 60% by weight of linoleic acid (Linoleic acid), 5 to 15% by weight of alpha linoleic acid (Alpha linoleic acid) relative to the total weight of the natural oil % And fatty acids other than these may be included in the balance.

The aromatic resin has a softening point of 90 ° C to 130 ° C, a glass transition temperature (T _g ) of 50 ° C to 80 ° C, and a weight ratio of aromatic hydrocarbons to aliphatic hydrocarbons of 30 to 60: 40 to 70 days. Can be.

The aromatic resin may be a copolymer of styrene and alpha-methylstyrene (α-metylstyrene).

According to another embodiment of the present invention, there is provided a tire including a tire tread manufactured using the rubber composition for the tire tread.

The rubber composition for tire treads of the present invention can maximize the wet grip performance and wear performance in a trade-off relationship while all performances are balanced according to the compound characteristics for all seasons.

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

Rubber composition for a tire tread according to an embodiment of the present invention is a raw material rubber containing an emulsion-polymerized styrene-butadiene rubber (E-SBR), a reinforcing filler comprising silica, a natural oil, and Aromatic resins.

That is, the rubber composition for the tire tread is a combination of the emulsion polymerized styrene-butadiene rubber, the silica, the natural oil, and the aromatic resin, and all performances are balanced according to the characteristics of tires for the four seasons, and recently, importance is being emphasized. It maximizes wet and wear performance.

Currently, four-year tires are usually compounded with the concept of maximizing wet performance by using solution-polymerized styrene-butadiene rubber (S-SBR) with high glass transition temperature (High T _g ). to be.

However, in the case of solution-polymerized styrene-butadiene rubber, compared to emulsion polymerized styrene-butadiene rubber, it has a low molecular weight, which is disadvantageous for abrasion performance, and has a feature that is also disadvantageous in terms of processability in the current trend of very high silica content.

Accordingly, in the present invention, an emulsified polymerized styrene-butadiene rubber capable of applying a high content of silica and maximizing wear performance is included as a raw material rubber.

The E-SBR may have a weight average molecular weight of 1,000,000 g / mol to 2,500,000 g / mol, and more specifically 1,700,000 g / mol to 2,300,000 g / mol. If the weight-average molecular weight of the E-SBR is less than 1,000,000 g / mol, it may be detrimental to abrasion performance, and when it exceeds 2,500,000 g / mol, processing may be difficult, and current technology may make rubber production itself difficult.

The E-SBR may have a glass transition temperature (T _g ) of -35 ° C to -60 ° C, and more specifically -45 ° C to -55 ° C. When the glass transition temperature of the E-SBR is less than -35 ° C, the glass transition temperature of the rubber composition becomes high, so that winter performance and abrasion performance of the tire for four seasons may be vulnerable, and when it exceeds -60 ° C, wet performance This may degrade and the tread stiffness may be weakened.

The E-SBR may be included in 30 parts by weight to 60 parts by weight among 100 parts by weight of the raw rubber, and more specifically, in 30 parts by weight to 50 parts by weight. When the content of the E-SBR is less than 30 parts by weight, the effect of improving wear performance may be negligible, and when it exceeds 60 parts by weight, it may be vulnerable to wet performance.

Meanwhile, the raw rubber may further include any one selected from the group consisting of natural rubber, synthetic rubber, and combinations thereof in addition to the E-SBR.

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

The general natural rubber may be any of those known as natural rubber, and the origin and the like are not limited. The natural rubber includes cis-1,4-polyisoprene as a main body, but may also include trans-1,4-polyisoprene depending on the required characteristics. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main body, natural rubber containing trans-1,4-isoprene as a main body, such as Valata, which is a kind of rubber from Sapota family in South America, is mainly used as the main rubber. Rubber may also be included.

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

Synthetic rubber in the above 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, bromomethyl styrene butyl rubber, maleic styrene butadiene rubber, carboxylic acid styrene butadiene rubber, epoxy isoprene rubber, maleic ethylene propylene rubber, carboxylic acid Nitrile butadiene rubber, brominated polyisobutyl isoprene-co-paramethyl styrene (brominated polyisobutyl isoprene-co-paramethyl styrene, BIMS), and combinations thereof.

For example, the raw rubber may be composed of the E-SBR and BR.

Particularly, the BR may more preferably use a high-cis butadiene rubber. The high-cis butadiene rubber has a cis-1,4 content of 95% by weight or more and a glass transition temperature (T _g ) of -104 ° C to -107 ° C. The high-cis butadiene rubber has an effect of releasing low-temperature properties and rebound elasticity within the range of the cis-1,4 content and the glass transition temperature.

The BR may be included in 20 parts by weight to 40 parts by weight among 100 parts by weight of the raw rubber. When the content of BR is less than 20 parts by weight, it may be vulnerable to abrasion, and when it exceeds 40 parts by weight, extrusion processability may be deteriorated in the tread rubber composition.

In addition, the rubber composition for a tire tread contains a high content of silica as a reinforcing agent in order to improve braking performance on a wet road surface.

That is, the silica may be included in 90 parts by weight to 140 parts by weight based on 100 parts by weight of the raw rubber, and more specifically, 90 parts by weight to 130 parts by weight. When the content of the silica is less than 90 parts by weight based on 100 parts by weight of the raw rubber, high performance may be difficult to implement, and when it exceeds 140 parts by weight, refining workability may be deteriorated and vulnerable to wear.

The silica may have a CTAB (cetyl trimethyl ammonium bromide) adsorption specific surface area of 150 m2 / g to 170 m2 / g. When the specific surface area of the silica is small, dispersion is improved, and hardness and low elongation modulus are lowered, so that braking performance on a wet road surface is advantageous, and at the same time, reinforcement is improved and high elongation modulus is increased.

When the CTAB adsorption specific surface area of the silica exceeds 170 m 2 / g, the mixing property with the raw material rubber decreases and the reinforcing property decreases, thereby reducing the rubber strength. It may have an adverse effect that the reinforcement is weakened.

The silica may be either wet or dry, and commercially available products include Ultrasil VN2 (manufactured by Degussa Ag), Ultrasil VN3 (manufactured by Degussa Ag), Z1165MP (manufactured by Rhodia), or Z165GR (manufactured by Rhodia). Can be.

Optionally, a coupling agent may be further included to improve the dispersibility of the silica.

Examples of the coupling agent include sulfide-based silane compounds, mercapto-based silane compounds, vinyl-based silane compounds, amino-based silane compounds, glycidoxy watch silane compounds, nitro-based silane compounds, chloro-based silane compounds, methacryl-based silane compounds, and combinations thereof Any one selected from the group consisting of can be used, and sulfide-based silane compounds can be preferably used.

The coupling agent may be included in 1 part by weight to 20 parts by weight based on 100 parts by weight of the raw rubber. When the content of the coupling agent is less than 1 part by weight, the dispersibility improvement of the silica is insufficient, and thus the processability of the rubber may be deteriorated or the low fuel efficiency may be deteriorated. When the content exceeds 20 parts by weight, the interaction between the silica and the rubber is too strong. Low fuel efficiency may be excellent, but braking performance may be degraded.

The rubber composition for tire treads includes E-SBR as a raw rubber, and contains a high content of silica as a reinforcing filler, and in addition, by replacing natural oils with natural oils, the abrasion performance is further improved. will be.

Specifically, the natural oil has some double bonds, and the glass transition temperature (T _g ) is low, thereby increasing the polysulfide system in the crosslinked structure and lowering the glass transition temperature, thereby further improving wear performance.

The natural oil includes 15% to 30% by weight of oleic acid, 40% to 60% by weight of linoleic acid, and 5% to 15% of alpha linoleic acid by weight relative to the total weight of the natural oil. Soybean oil may be used, including the weight percent, and the balance of fatty acids other than these.

If the proportion of oleic acid is less than 15% by weight, the wear resistance performance is excellent, but there may be a trade-off of braking performance and rolling resistance on a wet road surface, and when it exceeds 30% by weight, on the contrary, braking on a wet road surface The trade-off of performance and rolling resistance is minimal, but the wear-resistant performance effect can also be negligible.

The soybean oil may have a specific gravity of 0.90 to 0.93, an iodine value of 124 g / 100g to 139 g / 100g, and a saponification value of 188 mgKOH / g to 195 mgKOH / g. In addition, the soybean oil may have a weight average molecular weight of 850 g / mol to 900 g / mol. The soybean oil has a total content of PAHs of 3% by weight or less with respect to the whole oil, and can provide an eco-friendly tire with a kinematic viscosity of 95 or more (210 ° F SUS), and the rubber composition for tire tread containing the soybean oil is low temperature It has excellent properties and fuel efficiency, but also has favorable properties for environmental factors such as cancer-causing potential of PAHs.

The soybean oil may be to extract soybean oil components using a compression method or a solvent extraction method.

First, the compression method may be a washing step, a drying step, a milking step, a aging step, and a precipitation step. The drying step may be to wash the selected soybeans and then dry them for 2 hours to 3 hours in a suction-type ventilation drying method with a slight heat of 50 ° C to 70 ° C. The milking step may be to extract the oil between the dried soybeans between 80 ° C and 90 ° C with a conventional compactor or an expeller machine. The aging and precipitation step may be to separate the clear oil by removing the precipitate by precipitating foreign substances while aging the oil extracted through the milking process at room temperature for 7 to 10 days.

Next, the solvent extraction method may be to use an organic solvent such as hexane, alcohol, acetone, benzene, chloromethane, ether. Soybean may be immersed in the organic solvent to extract oil components and separate only oil.

The natural oil may be included in 5 parts by weight to 30 parts by weight based on 100 parts by weight of the raw rubber, and more specifically, 10 parts by weight to 25 parts by weight. When the content of the natural oil is less than 5 parts by weight based on 100 parts by weight of the raw rubber, the effect of lowering the glass transition temperature (Tg) may be insignificant and thus difficult to maximize winter performance or abrasion performance. It is too low and tread pushing may occur during dry braking.

However, in order to improve the abrasion performance of the rubber composition for tire treads, E-SBR is included as a raw rubber, and a high content of silica is used as a reinforcing filler, while natural oil is included, which is disadvantageous for wet performance. .

Accordingly, the rubber composition for tire treads further includes an aromatic resin, thereby improving wet / dry grip performance while maintaining wear performance.

The aromatic resin may have 8 to 10 carbon atoms, and may be a C9 pure-monomer aromatic resin having 9 carbon atoms. The 8-10 carbon pure-monomer aromatic resin further improves the tack performance between the rubber and the rubber, and improves the mixing, dispersibility, and processability of other additives such as fillers to improve the rubber. It can serve as a pressure-sensitive adhesive that contributes to the improvement of the physical properties.

The 8 to 10 carbon-based pure-monomer aromatic resin is specifically vinyl toluene resin (Vinyltoluenes), dicyclopentadiene resin (Dicyclopentadiene), indene resin (Indene), methyl styrene resin (Methylstyrene), styrene resin ( Styrene), methyl indenes (Methyl indenes), and may be an aromatic resin having 8 to 10 carbon atoms selected from the group consisting of a combination thereof, and specific examples of styrene (styrene) and alpha-methylstyrene (α-metylstyrene) It may be a copolymer.

In addition, the aromatic resin has a softening point of 90 ° C to 130 ° C, a glass transition temperature (T _g ) of 50 ° C to 80 ° C, and a weight ratio of aromatic hydrocarbons to aliphatic hydrocarbons of 30 to 60:40 to 40 ° C. When the 70 is to increase the wet performance of the tread rubber composition, the effect may be increased even with a small amount. When the weight ratio of the aromatic hydrocarbon is less than 30, the glass transition temperature is too high and the rolling resistance performance may be deteriorated, and when it exceeds 60, the wet reinforcing effect may be insignificant.

The aromatic resin may be included in 10 parts by weight to 30 parts by weight based on 100 parts by weight of the raw rubber. If the content of the aromatic resin is less than 10 parts by weight based on 100 parts by weight of the raw rubber, there may be little effect in increasing wet performance, and if it exceeds 30 parts by weight, the glass transition temperature of the rubber composition becomes too high, resulting in cracks at low temperatures. (Cold crack) may occur, and the aromatic resin serves as a processing aid, so that the rubber composition may be too soft.

The rubber composition for the tire tread is a combination of the emulsion polymerized styrene-butadiene rubber, the silica, the natural oil, and the aromatic resin, all performances are balanced according to the characteristics of the tires for the four seasons, and the wetness that has recently been highlighted is ( Wet) and wear performance are maximized.

Specifically, the rubber composition for tire treads can be applied with a high content of silica, and includes an emulsion polymerized styrene-butadiene rubber as a raw material rubber that can maximize abrasion performance, and replaces the existing petroleum-based oils to natural oils. By including, it is to further improve the wear performance.

However, in this combination, all but silica having a high content is advantageous for abrasion performance, but it is a concept compounded in a disadvantageous direction for wet performance. Thus, by using the aromatic resin, it is possible to improve wet / dry grip performance while maintaining abrasion performance.

The rubber composition for tire treads may optionally further include various additives such as additional vulcanizing agents, vulcanization accelerators, vulcanization accelerators, anti-aging agents, softeners or adhesives. Any of the various additives may be used as long as they are commonly used in the field to which the present invention pertains, and their content is not particularly limited as it is in accordance with the compounding ratio used in the rubber composition for tire treads.

The rubber composition for the tire tread is not limited to the tread (tread cap and tread base), and may be included in various rubber components constituting the tire. Examples of the rubber component include sidewalls, sidewall inserts, apexes, chafers, wire coats, or inner liners.

Tire according to another embodiment of the present invention is manufactured using the rubber composition for the tire tread. The method for manufacturing a tire using the rubber composition for a tire tread can be applied to any method that is conventionally used for the production of tires, and detailed description is omitted herein.

The tire may be a tire for a passenger car, a tire for a sports utility vehicle (SUV), a racing tire, an airplane tire, an agricultural machinery tire, an off-the-road tire, a small truck tire, a truck tire, or a bus tire. . In addition, the tire may be a radial tire or a bias tire, and is preferably a radial tire.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[Production Example: Preparation of rubber composition]

A rubber composition for tire treads according to Examples and Comparative Examples was prepared using the composition shown in Table 1 below. The production of the rubber composition was in accordance with a conventional method for producing the rubber composition.

Comparative Example 1 Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 E-SBR ¹⁾ - 43 43 43 73 - S-SBR ²⁾ 73 30 30 30 - 73 BR ³⁾ 27 27 27 27 27 27 High silica ⁴⁾ - 132 132 - 132 132 Low silica ⁵⁾ 80 - - 90 - - Natural oils ⁶⁾ - 27 27 27 27 27 Petroleum oil ⁷⁾ 47 25 25 25 25 25 Aromatic resin ⁸⁾ - 18 - 18 18 18 Resin ⁹⁾ 18 - 18 - - - Other ¹⁰⁾ 10 10 10 10 10 10

(Unit: parts by weight)

1) E-SBR: the weight average molecular weight is 2,000,000 g / mol, and the glass transition temperature (T _g ) is -53C

2) S-SBR: Lanxess' VSL2438 product

3) BR: cis content of 96% by weight or more

4, 5) Silica: CTAB adsorption specific surface area is 160 ㎡ / g

6) Natural oil: Soybean oil containing 25% by weight of oleic acid, 52.5% by weight of linoleic acid, and the balance of fatty acids other than these.

7) Petroleum-based oil: N # 2 products from Kukdong Oil

8) Aromatic resin: softening point is 103 ℃, glass transition temperature (T _g ) is 55 ℃, aromatic (Aromatic) hydrocarbons: Aliphatic (Aliphatic) hydrocarbons: Alkene (Alkene) = 51: 48: 1 (weight ratio)

9) Resin: Kolon C5 resin product

10) Others: 0.7 parts by weight of vulcanizing agent, 2.2 parts by weight of vulcanization accelerator, etc.

[Experimental Example 1: Measurement of tensile properties at room temperature of the prepared rubber composition]

The rubber specimens prepared in Examples and Comparative Examples were measured for physical properties at room temperature, and the results are shown in Table 2 below.

Comparative Example 1 Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Hardness ¹⁾ 72 72 50 65 75 76 300% modulus ²⁾ 90 65 53 61 80 85 Tensile strength ³⁾ 180 170 150 160 185 190 Elongation ⁴⁾ 510 650 700 540 560 520 Rigid ⁵⁾ 405 550 420 417 430 420

1) Hardness (Shore A) was measured according to DIN 53505. The hardness indicates the adjustment stability, and the higher the value, the better the adjustment stability performance. 2) 300% modulus (kgf / cm 2) was measured according to the ISO 37 standard. 300% modulus indicates that the higher the value, the better the tensile properties.

3) Tensile strength (kgf / ㎠) was measured by the method of ASTM D 790, and the higher the value, the better the strength.

4) Elongation (%) means the elongation at break, and the method of measuring the strain value until the test piece breaks in the tensile tester in% was measured. The higher the elongation, the better the tensile properties.

5) Toughness (unit: kgf / cm ² ): Measured by ASTM method for measuring tensile strength. The higher the value, the better the wear performance (energy-tolerant force).

In general, when the 300% modulus is less than 60 kgf / cm 2, tread rolling may occur during dry braking. Therefore, in the case of a tire for four seasons, it should have a modulus of 300% or more of 60 kgf / cm2, and in the case of Comparative Example 2, a modulus of 300% is less than 60 kgf / cm2.

In addition, in the case of abrasion, since it is a force to withstand from external energy, the higher the toughness, the better the abrasion performance. In the case of Example 1, it can be seen that the toughness is the best.

[Experimental Example 2: Measurement of viscoelasticity of the prepared rubber composition]

The viscoelasticity of the rubber specimens prepared in Examples and Comparative Examples was measured, and the results are shown in Table 3 below.

The viscoelasticity was measured using a RDS (Rheometrics Dynamic Spectrometer) meter measuring G ", 0 ℃ tanδ under 10 Hz Frequency at 0.5% strain. In Table 3 below, 0 ℃ tanδ G" (Loss Modulus) has a numerical value. The higher the wet performance, the better.

Comparative Example 1 Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 0 ℃ tanδ 0.203 0.235 0.180 0.215 0.213 0.221 0 ℃ G "(10E + 6) 5.4 8.7 4.2 6.5 6.8 6.1

In general, the wet performance of tires for all seasons is best represented by 0 ° C. tanδ and G ”, and it can be seen that Example 1 is the best. In addition, Example 1 was manufactured from tires and evaluated for actual vehicles. It was confirmed that the effect of Wet Braking (Wet Braking) performance is improved by 15%.

[Experimental Example 3: Measurement of low-temperature viscoelasticity of the prepared rubber composition]

The viscoelasticity of the rubber specimens prepared in Examples and Comparative Examples was measured at low temperature (-40 ° C to -20 ° C), and the results are shown in Table 4 below.

The viscoelasticity was measured by using a RDS (Rheometrics Dynamic Spectrometer) measuring G 'from -40 ° C to -20 ° C under 10 Hz Frequency at 0.5% strain. In Table 4, G 'indicates that the lower the value, the better the snow performance.

Comparative Example 1 Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 T _g -25 ℃ -38 ℃ -48 ℃ -40 ℃ -25 ℃ -23 ℃ -40 ℃ G ' 2.90E + 08 2.20E + 08 1.50E + 08 2.30E + 08 3.00E + 08 3.00E + 08 -30 ℃ G ' 1.40E + 08 9.00E + 07 5.65E + 07 9.10E + 07 1.50E + 08 1.60E + 08 -20 ℃ G ' 9.00E + 07 5.80E + 07 1.20E + 07 6.00E + 07 9.50E + 07 9.00E + 07 G 'index 100 136 160 134 99 98

In general, the T _g of the tire for all seasons is between -25 ° C and -40 ° C, and the lower the T _g , the better the snow performance. In the case of the G 'index, Comparative Example 2 and Comparative Example 3 are the best, but in the case of Comparative Examples 2 and 3, the balance between wet performance and abrasion performance is not balanced, so that when considering overall performance, Example 1 is the best wet. It can be seen that it has performance and wear performance.

[Experimental Example 4: Measurement of low-temperature viscoelasticity of the prepared rubber composition]

In Example 1 and in Example 2, except for using an aromatic hydrocarbon: aliphatic hydrocarbon: alkene = 12: 85: 3 (weight ratio) aromatic resin was used in the same manner as in Example 1 and prepared in Example 2 For, wet breaking and G "(@ 0 ° C) were measured, and the results are shown in Table 5 below.

Example 1 Example 2 Wet Breaking 100 95 G "(@ 0 ℃) 8.7 7.1

Referring to Table 5, it can be seen that Example 1 using an aromatic resin having a higher proportion of aromatic hydrocarbons has improved wet performance compared to Example 2. In addition, Mooney viscosity with respect to Example 1 and Comparative Example 5 , Extrusion index, productivity and bubble rate were measured, and the results are shown in Table 6 below.

Example 1 Comparative Example 5 Mooney viscosity ¹⁾ 65 90 Extrusion index ²⁾ 100 80 Productivity (MPM) ³⁾ 15.0 12.0 Bubble rate ⁴⁾ 0.1% 0.5%

In Table 6, when the Mooney viscosity is high, the non-conformity rate is high in the refining process and the degree is particularly severe when high content silica is included. However, in the case of Example 1, it can be seen that the use of E-SBR reduces the non-conformity rate in refining as the Mooney viscosity decreases. In addition, the extrusion index is an index along the extrusion surface, and the productivity (MPM) is The higher the productivity, the lower the bubble ratio. Referring to Table 6, it can be seen that Example 1 is also excellent in productivity.

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 including 30 parts by weight to 60 parts by weight of emulsion-polymerized styrene-butadiene rubber,
90 parts by weight to 140 parts by weight of a reinforcing filler comprising silica,
5 to 30 parts by weight of natural oil, and
Aromatic resin 10 parts by weight to 30 parts by weight
Rubber composition for a tire tread comprising a. According to claim 1,
The emulsion polymerized styrene-butadiene rubber has a weight average molecular weight of 1,000,000 g / mol to 2,500,000 g / mol, and a glass transition temperature (T _g ) of -35 ° C to -60 ° C. According to claim 1,
The raw rubber is a rubber composition for tire treads that further comprises 20 parts by weight to 40 parts by weight of butadiene rubber having a cis content of 95% by weight or more. According to claim 1,
The natural oil is 15 to 30% by weight of oleic acid (Oleic acid), 40 to 60% by weight of linoleic acid (Linoleic acid), 5 to 15% by weight of alpha linoleic acid (Alpha linoleic acid) relative to the total weight of the natural oil %, And a rubber composition for tire treads containing a residual amount of fatty acids other than these. According to claim 1,
The aromatic resin has a softening point of 90 ° C to 130 ° C, a glass transition temperature (T _g ) of 50 ° C to 80 ° C,
A rubber composition for tire treads, wherein the weight ratio of aromatic hydrocarbons to aliphatic hydrocarbons is 30 to 60:40 to 70. According to claim 1,
The aromatic resin is a rubber composition for tire treads that is a copolymer of styrene and alpha-methylstyrene (α-metylstyrene). A tire comprising a tire tread manufactured using the rubber composition for a tire tread according to any one of claims 1 to 6.