KR102191448B1 - 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 using the same, wherein the rubber composition for a tire tread is a raw material containing 30 parts by weight to 60 parts by weight of emulsion-polymerized styrene-butadiene rubber. 100 parts by weight of rubber, 90 parts by weight to 140 parts by weight of a reinforcing filler containing silica, 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 rubber composition for the tire tread can maximize the wet grip performance and wear performance in a trade-off relationship while achieving a balance of all performances according to the compound characteristics for all seasons.

Description

A rubber composition for a tire tread, and a tire manufactured using the same TECHNICAL FIELD [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 in a trade-off relationship while achieving a balance of all performances according to the compound characteristics for all seasons ( It is to provide a rubber composition for tire tread that can maximize performance and wear performance and a tire manufactured using the same.

Due to the technological advancement of tires, tires are being developed and released according to each season and conditions of use, such as tires for summer, tires for winter, and tires for all seasons.

In particular, in the case of four-season tires, it is important to achieve a balance in all aspects of performance because they exhibit intermediate properties between the performance of summer tires and winter tires, and if any particular performance is bad, the marketability inevitably deteriorates.

In addition, when looking at the current trend of vehicles equipped with four-season tires, it can be seen that the overall vehicle weight is increasing as the demand for SUV vehicles is increasing and electric vehicles equipped with batteries are newly developed.

Accordingly, as the trend of such demand vehicles changes, conditions required for tires for all seasons as a whole 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 prominent, and the parts for wet and dry (Wet/Dry) braking are also used in various commodities to satisfy market demands. Additional pounding techniques need to be developed.

An object of the present invention is to provide a rubber composition for tire tread that can maximize the wet grip performance and abrasion performance in a trade-off relationship while achieving a balance of all performance according to the compound characteristics for all seasons. To provide.

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

According to an embodiment of the present invention, 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 including silica It provides a rubber composition for a tire tread comprising parts by weight, 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 material rubber may further include butadiene rubber having a cis content of 95% by weight or more in an amount of 20 to 40 parts by weight.

The natural oil is based on the total weight of the natural oil, oleic acid (Oleic acid) 15% to 30% by weight, linoleic acid (Linoleic acid) 40% to 60% by weight, alpha linoleic acid (Alpha linoleic acid) 5% to 15% by weight %, 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 an aromatic hydrocarbon and an aliphatic hydrocarbon is 30 to 60: 40 to 70 days. I can.

The aromatic resin may be a copolymer of styrene and alpha-methylstyrene.

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

The rubber composition for a tire tread of the present invention can maximize the wet grip performance and abrasion performance in a trade-off relationship while achieving a balance of all performances according to the compound characteristics for all seasons.

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

The rubber composition for a tire tread according to an embodiment of the present invention includes a raw material rubber including emulsion-polymerized styrene-butadiene rubber (E-SBR), a reinforcing filler including silica, a natural oil, and Contains 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, so that all performances are balanced according to the characteristics of the tires for all seasons, and the importance of the recently emerged It maximizes wet and wear performance.

Currently, all-season tires are generally compounded with a concept that maximizes wet performance by using solution-polymerized styrene-butadiene rubber (S-SBR) having a high glass transition temperature (High T _g ). to be.

However, solution-polymerized styrene-butadiene rubber has a lower molecular weight than emulsion-polymerized styrene-butadiene rubber, which is disadvantageous in abrasion performance, and in the current trend in which the silica content is very high, also has a disadvantage in processability.

Accordingly, in the present invention, a high content of silica can be applied and an emulsion polymerization styrene-butadiene rubber capable of maximizing abrasion 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. When the weight average molecular weight of the E-SBR is less than 1,000,000 g/mol, it may be disadvantageous in wear performance, and when it exceeds 2,500,000 g/mol, processing may be difficult, and rubber production itself may be difficult with the current technology.

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 may increase, resulting in weak winter performance and abrasion performance of all-season tires, and if it exceeds -60 °C, wet performance This may decrease and the tread stiffness may be weakened.

The E-SBR may be included in an amount of 30 to 60 parts by weight of 100 parts by weight of the raw rubber, and more specifically, 30 to 50 parts by weight. If the content of the E-SBR is less than 30 parts by weight, the effect of improving the wear performance may be insignificant, and if it exceeds 60 parts by weight, the wet performance may be weak.

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 used as long as it is known as natural rubber, and the country of origin is not limited. The natural rubber mainly contains cis-1,4-polyisoprene, but may also contain trans-1,4-polyisoprene depending on the required properties. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main body, the natural rubber includes trans-1,4-isoprene as a main body, such as Valata, a kind of rubber of the Sapota family from South America. It may also contain rubber.

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 in the above is styrene butadiene rubber (SBR), modified styrene butadiene rubber, butadiene rubber (BR), modified butadiene rubber, chlorosulfonated 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 propylenediene (EPDM) rubber, hypalon rubber, chloroprene rubber, Ethylene vinyl acetate rubber, acrylic rubber, hydrin rubber, vinyl benzyl chloride styrene butadiene rubber, bromomethyl styrene butyl rubber, styrene butadiene maleate rubber, carboxylic acid styrene butadiene rubber, epoxy isoprene rubber, ethylene propylene maleate rubber, carboxylic acid It may be any one selected from the group consisting of nitrile butadiene rubber, brominated polyisobutyl isoprene-co-paramethyl styrene (BIMS), and combinations thereof.

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

In particular, the BR may more preferably use high-cis butadiene rubber. The high-cis butadiene rubber may have 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 that low-temperature properties and repulsion elasticity are advantageous within the range of the cis-1,4 content and the glass transition temperature.

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

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

That is, the silica may be included in an amount of 90 to 140 parts by weight based on 100 parts by weight of the raw rubber, and more specifically, 90 to 130 parts by weight. If the content of the silica is less than 90 parts by weight based on 100 parts by weight of the raw rubber, it may be difficult to implement high performance, and if it exceeds 140 parts by weight, refining processability may be deteriorated and abrasion may be vulnerable.

The silica may have a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 150 m 2 /g to 170 m 2 /g. When the specific surface area of the silica is small, dispersion is improved and the hardness and low elongation modulus are lowered, so that braking performance on a wet road surface is advantageous, and reinforcement properties are improved, thereby increasing high elongation modulus.

When the CTAB adsorption specific surface area of the silica exceeds 170 ㎡/g, the mixing property with the raw material rubber decreases and the reinforcement property is weakened, and the rubber strength may decrease. If it is less than 150 ㎡/g, the lower surface area This can cause adverse effects of weakening reinforcement.

The silica may be prepared by a wet method or a dry method, and as commercial products, Ultrasil VN2 (manufactured by Degussa Ag), Ultrasil VN3 (manufactured by Degussa Ag), Z1165MP (manufactured by Rhodia) or Z165GR (manufactured by Rhodia), etc. I can.

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 silane compounds, nitro-based silane compounds, chloro-based silane compounds, methacrylic silane compounds, and combinations thereof. Any one selected from the group consisting of may be used, and a sulfide-based silane compound may be preferably used.

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. If the content of the coupling agent is less than 1 part by weight, the dispersibility of the silica may be insufficient and the processability of the rubber may decrease or the low fuel efficiency performance may be deteriorated.If the content of the coupling agent exceeds 20 parts by weight, the interaction between the silica and the rubber is too strong. The low fuel efficiency performance may be excellent, but the braking performance may be deteriorated.

The rubber composition for the tire tread includes E-SBR as a raw rubber, a high content of silica as a reinforcing filler, and contains natural oil by replacing the existing petroleum oil, thereby further improving abrasion performance. will be.

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

As the natural oil, based on the total weight of the natural oil, oleic acid 15% to 30% by weight, linoleic acid 40% to 60% by weight, alpha linoleic acid 5% to 15% It is possible to use soybean oil containing weight%, and the balance of fatty acids other than these.

If the ratio of oleic acid is less than 15% by weight, abrasion resistance is excellent, but there may be a trade-off in braking performance and rolling resistance on wet road surfaces.If it exceeds 30% by weight, braking on wet road surfaces on the contrary The tradeoff between performance and rolling resistance is insignificant, but the effect of wear resistance performance may also be insignificant.

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 may provide an eco-friendly tire with a total content of PAHs of 3% by weight or less and a kinematic viscosity of 95 or more (210 ℉ SUS) with respect to the entire oil, and the rubber composition for tire tread including the soybean oil is low temperature It has excellent properties and fuel efficiency, but also has advantageous properties against environmental factors such as cancer-causing potential of PAHs.

The soybean oil may be one for extracting the oil component using a compression method or a solvent extraction method.

First, the compression method may be prepared in a washing step, a drying step, a milking step, a aging step, and a precipitation step. The drying step may include washing the selected soybeans and drying them for 2 to 3 hours in a suction-type air drying method with low heat at 50° C. to 70° C. The milking step may be to extract the oil from 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 only clear oil by aging the oil extracted through the milking process at room temperature for 7 to 10 days and at the same time sedimenting foreign substances to remove the precipitate.

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

The natural oil may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the raw rubber, and more specifically, 10 to 25 parts by weight. If 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) is insignificant, so it may be difficult to maximize winter performance or wear performance, and if it exceeds 30 parts by weight, the modulus is It is too low and may cause tread slipping during dry braking.

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

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

The aromatic resin may have 8 to 10 carbon atoms, and may be a C9-based pure-monomer aromatic resin having 9 carbon atoms. The pure-monomer-based aromatic resin having 8 to 10 carbon atoms additionally further improves the tack performance between rubber and rubber, and improves the mixability, dispersibility and processability of other additives such as fillers. It can act as an adhesive that contributes to improving the physical properties of

The pure-monomer-based aromatic resin having 8 to 10 carbon atoms is specifically a vinyltoluene resin, a dicyclopentadiene resin, an indene resin, a methylstyrene resin, and a styrene resin ( Styrene), methyl indenes, and a combination thereof may be an aromatic resin having 8 to 10 carbon atoms selected from the group consisting of, a specific example of 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 an aromatic hydrocarbon and an aliphatic hydrocarbon is 30 to 60:40 to When the amount of 70 improves the wet performance of the tread rubber composition, the effect can 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 rotational resistance performance may be deteriorated, and when it exceeds 60, the wet reinforcing effect may be insignificant.

The aromatic resin may be included in an amount of 10 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 of increasing wet performance, and if it exceeds 30 parts by weight, the glass transition temperature of the rubber composition becomes too high and cracks at a low temperature. (Cold crack) may occur, and the aromatic resin may serve as a processing aid, and the rubber composition may become too soft.

The tire tread rubber composition is a combination of the emulsion-polymerized styrene-butadiene rubber, the silica, the natural oil, and the aromatic resin, so that all performance is balanced according to the characteristics of the tire for all seasons, and the importance of wet ( Wet) and wear performance are maximized.

Specifically, the rubber composition for the tire tread can be applied with a high content of silica and contains an emulsion polymerization styrene-butadiene rubber that can maximize abrasion performance as a raw material rubber, and replaces the existing petroleum-based oil. By including, the wear performance is further improved.

However, in such a combination, except for a high content of silica, it is a concept that is compounded in a direction that is advantageous in abrasion performance but is disadvantageous in 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 tread may optionally further include various additives such as an additional vulcanizing agent, a vulcanization accelerator, a vulcanization accelerator, an anti-aging agent, a softener or an adhesive. 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 depends on the blending ratio used in a conventional rubber composition for a tire tread.

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 components include sidewalls, sidewall inserts, apex, chafer, wire coat, or inner liner.

A tire according to another embodiment of the present invention is manufactured using the rubber composition for a tire tread. The method of manufacturing a tire using the rubber composition for a tire tread can be applied to any method as long as it is a method conventionally used for manufacturing a tire, and a detailed description thereof will be omitted herein.

The tire may be a tire for a passenger car, a tire for a sports utility vehicle (SUV), a tire for a race, an airplane tire, a tire for an agricultural machine, 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, preferably a radial tire.

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

[Production Example: Preparation of rubber composition]

A rubber composition for a tire tread according to the following Examples and Comparative Examples was prepared using the composition shown in Table 1 below. The preparation of the rubber composition was performed according to a conventional method for preparing a 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 oil 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 -53 ℃

2) S-SBR: Lanxess VSL2438 product

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

4, 5) Silica: CTAB adsorption specific surface area of 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 oil: Kukdong Petrochemical N#2 product

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

9) Resin: Kolon's C5 resin product

10) Others: 0.7 parts by weight of vulcanization 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]

Physical properties at room temperature were measured for the rubber specimens prepared in the Examples and Comparative Examples, 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 Stiffness ⁵⁾ 405 550 420 417 430 420

1) Hardness (Shore A) was measured according to DIN 53505. The hardness indicates the stability of adjustment, and the higher the value, the better the stability of adjustment. 2) The 300% modulus (kgf/cm2) was measured according to ISO 37 standard. The 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 (%) refers to the elongation at break, and the method was measured to indicate the strain value until the test piece is broken in a tensile tester in %. The higher the elongation rate, the better the tensile properties.

5) Stiffness (Toughness, unit: kgf/cm ² ): It was measured by ASTM method for measuring tensile strength. The higher the value, the better the wear performance (energy endurance).

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

In addition, in the case of wear, since it is a force withstanding from external energy, the higher the toughness is, the more advantageous the wear performance is.

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

Viscoelasticity was measured for the rubber specimens prepared in the Examples and Comparative Examples, and the results are shown in Table 3 below.

The viscoelasticity was measured by using a Rheometrics Dynamic Spectrometer (RDS) measuring instrument at 0.5% strain and under 10 Hz frequency, G" and 0 °C tanδ. In Table 3 below, 0 °C tanδ G" (Loss Modulus) has a numerical value. The higher it is, the more advantageous the wet performance is.

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 a four-season tire is best represented by 0°C tanδ and G", and it can be seen that Example 1 is the most excellent. In the case of Example 1, when the tire was manufactured and the actual vehicle was evaluated. It was confirmed that the wet braking performance was improved by 15%.

[Experimental Example 3: Low temperature viscoelasticity measurement of the prepared rubber composition]

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

The viscoelasticity was measured by using a Rheometrics Dynamic Spectrometer (RDS) measuring instrument from -40°C to -20°C under a frequency of 0.5% strain and 10 Hz. In Table 4 below, G'indicates that the lower the value, the more advantageous 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 a tire for all seasons is between -25°C and -40°C, and the lower the T _g is, the better for 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 wet performance and the abrasion performance are not balanced, so Example 1 is the best wet when considering the overall performance. 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 2, prepared in the same manner as in Example 1, except for using an aromatic resin having an aromatic hydrocarbon: aliphatic hydrocarbon: alkene = 12: 85: 3 (weight ratio) in Example 1 and Example 1, For the wet breaking and G" (@ 0 ℃) were measured, 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 of Example 1 and Comparative Example 5 was obtained. , Extrusion index, productivity and foaming 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 increases 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 non-conformity rate in refining decreases as the Mooney viscosity decreases due to the use of E-SBR. In addition, the extrusion index is an index according to the extrusion surface, and the productivity (MPM) is The higher it is, the more advantageous the productivity, and the lower the foaming rate, the more advantageous. 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 by those skilled in the art using the basic concept of the present invention defined in the following claims are also present. It belongs to the scope of rights of

Claims (7)

Emulsion-polymerized Styrene Butadiene Rubber 30 parts by weight to 60 parts by weight, cis content of 95% by weight or more, glass transition temperature (T _g ) of -104 ℃ to -107 ℃ butadiene 100 parts by weight of raw rubber containing 20 parts by weight to 40 parts by weight of butadiene rubber,
120 parts by weight to 140 parts by weight of a silica reinforcing filler,
5 to 30 parts by weight of natural oil, and
Containing 10 parts by weight to 30 parts by weight of an aromatic resin;
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 an aromatic hydrocarbon and an aliphatic hydrocarbon is 30 to 60: 40 to 70. A copolymer of styrene and alpha-methylstyrene;
Tire tread rubber composition, characterized in that. The method of 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. delete The method of claim 1,
The natural oil is based on the total weight of the natural oil, oleic acid (Oleic acid) 15% to 30% by weight, linoleic acid (Linoleic acid) 40% to 60% by weight, alpha linoleic acid (Alpha linoleic acid) 5% to 15% by weight %, and a balance of fatty acids other than these, a rubber composition for a tire tread. delete delete A tire comprising a tire tread manufactured using the rubber composition for a tire tread according to any one of claims 1, 2 and 4.