KR101381840B1 - Rubber composition for tire tread and tire manufactured by using the same - Google Patents

Abstract

(상기 화학식 1에서, 상기 Me는 알칼리금속이고, 상기 n은 1 내지 10의 정수이고, 상기 m은 1 내지 6의 정수이다)
상기 타이어 트레드용 고무 조성물은 장기 주행시 블럭강성을 향상시켜 초반과 동일한 주행을 할 수 있도록 하고, 칩 컷 성능, 초반 그립성능 및 그립 지속성을 향상시키면서도 내마모성 및 내구성이 유지될 수 있도록 한다.The present invention relates to a rubber composition for a tire tread and a tire manufactured using the same, which comprises 0.1 part by weight of styrene-butadiene rubber and 0.1 to aramid short fibers surface-treated with a compound represented by the following Chemical Formula 1 or a hydrate and polysulfide thereof: 10 parts by weight.
[Chemical Formula 1]

(In Formula 1, Me is an alkali metal, n is an integer of 1 to 10, m is an integer of 1 to 6)
The tire tread rubber composition improves block stiffness during long run to allow the same running as the early stage, and maintains wear resistance and durability while improving chip cut performance, early grip performance, and grip sustainability.

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 a tire tread and a tire manufactured using the same, which improves block stiffness during long-term driving so that the same running can be carried out as early as possible, while improving chip cut performance, early grip performance, and grip durability. And it relates to a rubber composition for a tire tread and a tire manufactured by using the same for maintaining the durability.

Tire tread is made of natural rubber or natural rubber and synthetic rubber as main raw materials, and reinforcing materials, anti-aging agents, softeners, vulcanizing agents and vulcanization accelerators are appropriately selected in order to improve physical properties and other properties of raw rubber.

In the tire, the tread is a part of the vehicle which is in direct contact with the ground as the vehicle moves, and thus, the tread portion is gradually worn out due to the friction between the tire and the ground and the heat generated by the friction, so the abrasion resistance and heat resistance should be excellent. .

The heat and wear resistance of tire treads is determined by the nature of the tread surface in contact with the ground. In particular, heat generation inevitably generated at high speeds causes a decrease in physical properties of the tire and a decrease in wear resistance.

In addition to the wear resistance and heat resistance, the vehicle rotates in a curve as well as straight, so the rolling resistance of the tire should be good according to the rotation of the vehicle. In addition, since the road surface gets wet due to rain or the road surface is often wetted by freezing or ice generated during the winter, the wet traction of the tire on the wet road surface should be excellent.

On the other hand, the conventional tire tread rubber has a problem in that the wear resistance and durability is sharply lowered when used in a rougher road surface situation than the conventional for the purpose of improving chip cut during off-road driving. That is, in order to improve chip cut performance, the carbon black filling amount was increased, the oil was reduced, and the reinforcing resin was used. However, the change in the physical properties is increased by increasing or decreasing these ingredients, and particularly in the off-road condition. When the driving proceeds, the chip cut shape may proceed at a high speed, which may cause difficulty in driving, and also may cause a problem of deterioration in durability and wear resistance.

Korea Patent Publication 2006-0134483 (Disclosure Date: December 28, 2006) Korean Published Patent Application No. 2007-0000860 (Disclosure Date: January 3, 2007) Korean Published Patent Application No. 2007-0095546 (Published on October 1, 2007)

An object of the present invention is to improve the block stiffness in the long run to achieve the same running as the initial, while improving the chip cut performance, early grip performance and grip durability, while maintaining the wear resistance and durability tire tread rubber composition To provide.

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 100 parts by weight of styrene-butadiene rubber, and aramid short fibers surface-treated with a compound represented by the formula (1) or a hydrate and polysulfide thereof 0.1 to 10 parts by weight.

[Chemical Formula 1]

In Formula 1, Me is an alkali metal, n is an integer of 1 to 10, and m is an integer of 1 to 6.

The polysulfide may be any one selected from the group consisting of compounds represented by the following formulas (2) to (6).

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

Wherein R ₁ and R ₂ are each independently selected from the group consisting of hydrogen, halogen, nitro, hydroxy, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aralkyl group having 1 to 12 carbon atoms , And m is an integer of 1 to 6.

The short aramid fibers may have an average length of 1.4 to 3.0 cm and an average diameter of 0.2 to 1.0 mm.

The short aramid fibers may be surface-treated with 2.0 to 10.0 parts by weight of the compound represented by Formula 1 or a hydrate thereof, and 5.0 to 7.5 parts by weight of polysulfide based on 100 parts by weight of the aramid short fibers.

The tire tread rubber composition may further include 1 to 30 parts by weight of carbon black having a nitrogen adsorption specific surface area of 30 to 300 m ² / g and a DBP (n-dibutyl phthalate) oil absorption of 60 to 180 cc / 100 g.

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

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

The rubber composition for tire treads according to one embodiment of the present invention includes 100 parts by weight of styrene-butadiene rubber, and 0.1 to 10 parts by weight of aramid short fibers surface-treated with a compound represented by the following Formula 1 or a hydrate and polysulfide thereof: .

Since the aramid short fibers surface-treated with the compound represented by Formula 1 or a hydrate thereof and polysulfide have excellent dispersibility to rubber, the rubber for tire treads including the surface-treated aramid short fibers has no heat generation Evenly and fast forward in the first half, it can improve the block stiffness and lead to faster grip performance in long run, wear resistance and durability is not deteriorated.

The tire tread rubber composition uses styrene-butadiene rubber as a raw material rubber. The styrene-butadiene rubber composition may be an emulsion-polymerized styrene-butadiene rubber (E-SBR) or a solution-polymerized styrene-butadiene rubber (S-SBR).

The E-SBR may have a styrene content of 40 to 50% by weight, a vinyl content of 10 to 20% by weight, and a glass transition temperature (Tg) of -30 to -40 ° C. The E-SBR has a lower glass transition temperature (Tg) and a lower vinyl content than S-SBR, and thus has a disadvantage in braking performance on wet roads, but may advantageously act on rotational resistance and wear performance. The E-SBR may preferably be used having a weight average molecular weight of 800,000 or more.

In addition, the E-SBR may contain 25 to 50 parts by weight of TDAE (Treated Distillate Aromatic Extract) oil per 100 parts by weight of the original rubber elastomer, and preferably may contain 35 to 40 parts by weight. When the E-SBR contains 25 to 50 parts by weight of TDAE oil per 100 parts by weight of the rubber elastomer, it can be expected to increase the flexibility of the E-SBR reduced by the influence of styrene.

The S-SBR may have a styrene content of 20 to 40% by weight, a vinyl content of 40 to 60% by weight, and a glass transition temperature (Tg) of -30 to -20 ° C. In the case of using the S-SBR having the above characteristics, since the hysteresis of the tire tread is increased, braking performance on a dry or wet surface can be improved at the same time.

In addition, the S-SBR may contain 25 to 50 parts by weight of TDAE oil per 100 parts by weight of the original rubber elastomer, preferably 35 to 40 parts by weight. When the S-SBR contains 25 to 50 parts by weight of TDAE oil per 100 parts by weight of the elastomeric elastomer, it is preferable in view of the increased flexibility of S-SBR reduced by the influence of styrene.

The surface treated aramid short fibers may have an average length of 1.4 to 3.0 cm, an average diameter of 0.2 to 1.0 mm, preferably an average length of 2.0 to 3.0 cm, and an average diameter of 0.6 to 0.8 mm. If the average length of the surface-treated aramid short fibers is less than 1.4cm there may be a problem of dispersion in the mixed phase, if more than 3.0cm may have a problem in manufacturing short fibers. In addition, when the average diameter of the short-treated aramid fibers is less than 0.2mm, there may be a dispersion problem on the mixing mixture, and when the average diameter of the aramid short fibers is greater than 1.0mm, the rubber is orientated (arranged in the same direction) after mixing, which is faster than the conventional one. It can lead to cracks.

The surface treated aramid short fibers may be included in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5.5 parts by weight, based on 100 parts by weight of the raw material rubber. When the content of the surface-treated aramid short fibers is less than 0.01 parts by weight, there is no large change, and when it exceeds 10 parts by weight, the hardness may be excessively increased to cause problems during extrusion.

On the other hand, the surface-treated aramid short fibers are preferably mixed in a rubber composition in a master batch form in that the dispersibility of the surface-treated aramid short fibers can be further improved. When the surface-treated aramid short fibers are added to the rubber composition in the form of a master batch, the master batch may include 0.5 to 10% by weight of the surface-treated aramid short fibers relative to the entire master batch, wherein the master batch May be included in an amount of 1 to 50 parts by weight based on 100 parts by weight of the styrene-butadiene rubber.

The master batch may be mixed with the surface treated aramid short fibers and the raw material rubber and the filler and then dried to form a master batch. In the master batch production, the mixed release temperature is preferably 150 to 165 ° C. When the mixed release temperature is less than 150 ° C, dispersion is difficult to be achieved, so it is difficult to expect the exothermic inhibitory performance as desired, and exceeds 165 ° C. In the case of heat generation may occur rather due to the bonding between the raw material rubber and the surface treated aramid short fibers.

The short aramid fibers are surface-treated with a compound represented by the following formula (1) or a hydrate thereof and polysulfide. The aramid short fibers surface-treated with the compound represented by Formula 1 or its hydrate and polysulfide are easily dispersed in the rubber composition and induce early grip performance of the tire tread block during high-speed off-road driving without deteriorating durability and abrasion resistance. And the second half grip performance can be maintained.

The aramid staple fiber may be prepared by mixing a compound represented by the formula (1) or its hydrate with the polysulfide to prepare a surface treatment solution, applying the prepared surface treatment solution to the aramid staple fiber, And immersing it in a treating solution. The surface treated aramid staple fibers may be prepared by surface treating the aramid fibers and then cutting the aramid fibers. Alternatively, the aramid fibers may be cut and then surface-treated.

[Chemical Formula 1]

In the above formula (1), Me is an alkali metal, for example, sodium or potassium, preferably sodium.

N is an integer of 1 to 10, and m may be an integer of 1 to 6.

The compound represented by the above formula (1) can also be used in the form of a hydrate or dihydrate.

The polysulfide may be any one selected from the group consisting of compounds represented by the following formulas (2) to (6).

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

Wherein R ₁ and R ₂ are each independently selected from the group consisting of hydrogen, halogen, nitro, hydroxy, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aralkyl group having 1 to 12 carbon atoms , And preferably hydrogen or an alkyl group.

M is an integer of 1 to 6, preferably an integer of 1 to 4.

The surface-treated aramid short fibers are 2.0 to 10.0 parts by weight, preferably 5.0 to 8.0 parts by weight, and 5.0 to 7.5 parts by weight of the compound represented by Formula 1 or a hydrate thereof, based on 100 parts by weight of the aramid short fibers , Preferably from 5.5 to 7.0 parts by weight.

If the content used for the surface treatment of the compound represented by the formula (1) is less than 2.0 parts by weight based on 100 parts by weight of the short fiber of the amaride, there is no particular change, and when it exceeds 10.0 parts by weight, a problem of inducing excessive vulcanization may occur. Can be. In addition, when the content used for the surface treatment of the polysulfide is less than 5.0 parts by weight with respect to 100 parts by weight of the short fiber of the amaride may cause a problem that the vulcanization rate is delayed, if the content exceeds 7.5 parts by weight May occur.

The tire tread rubber composition may further include carbon black as a filler.

The carbon black may have a nitrogen adsorption specific surface area (N ₂ SA) of 30 to 300 m ² / g and a DBP (n-dibutyl phthalate) oil absorption of 60 to 300 cc / 100 g, but the present invention This is not limited to this.

When the carbon adsorption specific surface area of the carbon black exceeds 300 m ² / g, the workability of the rubber tread rubber composition may be disadvantageous, and when the carbon black is less than 30 m ² / g, reinforcing performance by the carbon black filler may be disadvantageous. In addition, when the DBP oil absorption of the carbon black exceeds 300cc / 100g, the workability of the rubber tread rubber composition may be lowered, and when the carbon black is less than 60cc / 100g, reinforcing performance by the carbon black filler may be disadvantageous.

The carbon black may be included in an amount of 1 to 30 parts by weight, and 20 to 25 parts by weight based on 100 parts by weight of the raw material rubber. If the content of the carbon black is less than 1 part by weight, the reinforcing performance of the carbon black as a filler may be deteriorated. If the content of the carbon black exceeds 30 parts by weight, the processability of the rubber composition may be deteriorated.

The tire tread rubber composition may optionally further include various additives such as additional vulcanizing agents, vulcanization accelerators, vulcanization accelerators, other fillers, coupling agents, anti-aging agents, softeners or pressure-sensitive adhesives. The various additives can be used as long as they are commonly used in the field to which the present invention belongs. The content thereof is not particularly limited as long as it depends on a compounding ratio used in a rubber composition for a tire tread.

As the vulcanizing agent, a sulfur vulcanizing agent can be preferably used. The sulfur vulcanizing agent is an inorganic vulcanizing agent such as powder sulfur (S), insoluble sulfur (S), precipitated sulfur (S), colloid sulfur, etc., tetramethylthiuram disulfide (TMTD) Organic vulcanizing agents such as tetraethyltriuram disulfide (TETD) and dithiodimorpholine can be used. As the sulfur vulcanizing agent, a vulcanizing agent which produces elemental sulfur or sulfur, for example, amine disulfide, polymer sulfur and the like can be used.

It is preferable that the vulcanizing agent is contained in an amount of 0.5 to 4.0 parts by weight based on 100 parts by weight of the raw material rubber in view of providing a vulcanization effect that is less sensitive to heat and chemically stable.

The vulcanization accelerator refers to an accelerator that promotes the vulcanization rate or accelerates the retardation in the initial vulcanization step.

Examples of the vulcanization accelerator include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamate, aldehyde-amine, aldehyde-ammonia, imidazoline, Or a combination thereof.

Examples of the sulfenamide type vulcanization accelerator include N-cyclohexyl-2-benzothiazyl sulfenamide (CBS), N-tert-butyl-2-benzothiazyl sulfenamide (TBBS), N, N-dicyclohexyl -2-benzothiazyl sulfenamide, N-oxydiethylene-2-benzothiazyl sulfenamide, N, N-diisopropyl-2-benzothiazole sulfenamide, and combinations thereof Based compound can be used.

Examples of the thiol-based vulcanization accelerator include 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), sodium salt of 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole , A copper salt of 2-mercaptobenzothiazole, a cyclohexylamine salt of 2-mercaptobenzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- Ethyl 4-morpholinothio) benzothiazole, and combinations thereof. The thiazole-based compound may be used alone or in combination of two or more thereof.

Examples of the thiuram-based vulcanization accelerator include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylthiuram disulfide, dipentamethylthiuram monosulfide, dipentamethylene Any one of thiuram-based compounds selected from the group consisting of thiuram tetrasulfide, dipentamethylenethiuram hexasulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide, and combinations thereof can be used.

Examples of the thiourea vulcanization accelerator include thiourea compounds selected from the group consisting of thiacarbamide, diethyl thiourea, dibutyl thiourea, trimethyl thiourea, diorthotolyl thiourea, and combinations thereof. Compounds may be used.

Examples of the guanidine-based vulcanization accelerator include guanidine-based compounds selected from the group consisting of diphenyl guanidine, diorthotolyl guanidine, triphenyl guanidine, orthotolyl biguanide, diphenyl guanidine phthalate, and combinations thereof .

Examples of the dithiocarbamate-based vulcanization accelerator include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, Zinc dibutyldithiocarbamate, zinc diamidithiocarbamate, zinc dipropyldithiocarbamate, complexation of zinc with piperidinedithiocarbamate and piperidine, zinc hexadecylisopropyldithiocarbamate, octadecyl Isopropyl dithiocarbamic acid zinc zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, penta methylenedithiocarbamate, sodium selenium dimethyldithiocarbamate, diethyldithiocarbamate, sodium diethyldithiocarbamate, Cadmium dithiocarbamate, and combinations thereof. The dithiocarbamic acid-based compound may be used alone or in combination of two or more thereof.

Examples of the aldehyde-amine type or aldehyde-ammonia type vulcanization accelerator include aldehyde selected from the group consisting of acetaldehyde-aniline reactant, butylaldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant, -Amine-based or aldehyde-ammonia-based compounds may be used.

As the imidazoline-based vulcanization accelerator, for example, an imidazoline-based compound such as 2-mercaptoimidazoline can be used. Examples of the xanthate vulcanization accelerator include xanthates such as zinc dibutylxanthogenate Compounds may be used.

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 improvement and rubber property enhancement through vulcanization speed promotion.

The vulcanization accelerating assistant may be any one selected from the group consisting of an inorganic vulcanization accelerator aid, an organic vulcanization accelerator aid, and a combination thereof, which is used in combination with the vulcanization accelerator to complete the promoting effect thereof .

As the inorganic vulcanization accelerating aid, any one selected from the group consisting of zinc oxide (ZnO), zinc carbonate, magnesium oxide (MgO), lead oxide, potassium hydroxide and combinations thereof may be used have. As the organic vulcanization accelerating auxiliary, there may be selected from the group consisting of stearic acid, zinc stearate, palmitic acid, linoleic acid, oleic acid, lauric acid, dibutyl ammonium oleate, derivatives thereof, Can be used.

In particular, the zinc oxide and the stearic acid may be used together as the vulcanization accelerating assistant. In this case, the zinc oxide is dissolved in the stearic acid to form an effective complex with the vulcanization accelerator, Thereby facilitating the crosslinking reaction of the rubber.

When the zinc oxide and the stearic acid are used together, they may be used in an amount of 1 to 5 parts by weight and 0.5 to 3 parts by weight, respectively, based on 100 parts by weight of the raw rubber to serve as a proper vulcanization accelerator. If the content of the zinc oxide and the stearic acid is less than the above range, the vulcanization rate may be slow and the productivity may be deteriorated. If the content exceeds the above range, the scorch phenomenon may occur and the physical properties may be deteriorated.

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

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.

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 may be any one selected from the group consisting of? -Methacryloxypropyltrimethoxysilane,? -Methacryloxypropylmethyldimethoxysilane,? -Methacryloxypropyldimethylmethoxysilane, and combinations thereof Lt; / RTI >

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 softening agent is added to the rubber composition in order to impart plasticity to the rubber to facilitate processing or to decrease the hardness of the vulcanized rubber, and means an oil or other material used in rubber compounding or rubber production. The softening agent means an oil contained in a process oil or other rubber composition. The softener may be selected from the group consisting of petroleum oils, vegetable oils, and combinations thereof, but the present invention is not limited thereto.

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

Examples of the paraffin oil include P-1, P-2, P-3, P-4, P-5 and P-6 of Mychang Oil Co., N-1, N-2 and N-3 of Kokai Co., Ltd., and representative examples of the aromatic oils include A-2 and A-3 of Mingchang Oil Co.,

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.

Particularly, the oil used as the softening agent preferably has a total content of PAHs components of not more than 3 wt%, a kinematic viscosity of not less than 95 (210 S SUS), an aromatic component of 15 to 25 wt%, a naphthene component Of 27 to 37% by weight and a paraffinic component of 38 to 58% by weight 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.

Examples of the vegetable oils include vegetable oils such as castor oil, cottonseed oil, linseed oil, canola oil, soybean oil, palm oil, palm oil, peanut oil, pine oil, pine tar, tall oil, cone oil, rice bran oil, safflower oil, sesame oil, , Jojoba oil, macadamia nut oil, four flower oil, tung oil, and combinations thereof.

It is preferable that the softening agent is used in an amount of 0 to 150 parts by weight based on 100 parts by weight of the raw material rubber in order to improve workability of the raw material rubber.

The rubber composition for a tire tread can be produced through a conventional two-step continuous manufacturing process. That is, during the finishing step in which the first stage of thermomechanical treatment or kneading and the crosslinking system are mixed at a maximum temperature of 110 to 190 占 폚, preferably at a high temperature of 130 to 180 占 폚, typically less than 110 占 폚, And a second step of mechanical treatment at a low temperature of 40 to 100 DEG C in a suitable mixer, but the present invention is not limited thereto.

The rubber composition for a tire tread is not limited to a tread (a tread cap and a tread base) but may be included in various rubber components constituting the tire. Said 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 the tire tread. The method of manufacturing a tire using the rubber composition for a tire tread may be any method conventionally used for manufacturing a tire, and a detailed description thereof will be omitted herein.

The tires may be automobile tires, racing tires, airplane tires, agricultural tires, off-the-road tires, truck tires or bus tires. Further, the tire may be a radial tire or a bias tire, and preferably a radial tire.

The rubber composition for tire treads of the present invention improves block stiffness during long-term driving so that the same running as in the early stage can be achieved, and wear resistance and durability can be maintained while improving chip cut performance, early grip performance, and grip sustainability.

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.

[Production Example: Production of Rubber Composition]

Rubber compositions for tire treads according to the following Examples and Comparative Examples were prepared using the compositions shown in Table 1 below. The production of the rubber composition was in accordance with the usual production method of the rubber composition.

Unit: parts by weight Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Rubber raw material ⁽¹⁾ 125.5 125.5 125.5 125.5 125.5 125.5 125.5 Carbon Black ⁽²⁾ 73.7 23.7 23.7 23.7 23.7 23.7 23.7 Surface treatment
Aramid
Short fiber ⁽³⁾ - 0.1 0.5 1.0 1.5 2.5 5.0 Zinc oxide 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Stearic acid 1.0 1.0 1.0 1.0 1.0 1.0 1.0 brimstone 1.0 1.0 1.0 1.0 1.0 1.0 1.0 accelerant 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Accelerator (DPG) 2 2 2 2 2 2 2

(1) Styrene-butadiene rubber: styrene content of 45% by weight, vinyl content of 15% by weight, glass transition temperature (Tg) is -35 ℃. Contains 25.5 parts by weight of TDAE oil based on 100 parts by weight of rubber.

(2) Carbon black: The nitrogen adsorption specific surface area is 160 m ² / g, and the oil absorption of DBP (n-dibutyl phthalate) is 210cc / 100g.

(3) Surface-treated aramid short fibers: Aramid short fibers (average length is 2.6cm, average diameter is 0.8mm) Compound represented by the formula (1) with respect to 100 parts by weight (Me is Na, m is 1 , n is 6) 7.0 parts by weight of a dihydrate and the compound represented by the formula (6) (R ₁ and R ₂ is hydrogen, m is 2) surface treated with 6.5 parts by weight.

[Experimental Example: Measurement of Physical Properties of the Rubber Composition]

The physical properties of the rubber specimens prepared in Examples and Comparative Examples were measured and the results are shown in Table 2 below.

-The grip performance was made by using a rubber composition prepared in the above Examples and Comparative Examples to manufacture a tire of size 280 / 640R18 F200 consisting of a tread section, and then set the pneumatic pressure to 200 kPa, and the test driver performed the circuit course (2 km) under dry conditions. Lap time was measured at every run after 10 consecutive runs to evaluate the initial grip performance and the sustainability of the grip performance.

Grip performance score: 1 (very bad) to 10 (very good)

- 300% Modulus and elongation were measured according to ISO 37 standard.

Abrasion was measured according to JIS K6264 and expressed based on a comparative example.

Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Initial grip performance 4 8.5 10 9 8 7 6.5 Late grip performance 2 7 9 9 7 6.5 5 300% Modulus (Mpa) 62.1 62.2 67.3 71.1 69.4 72.1 74.3 Elongation (%) 790 861 839 821 801 760 742 Wear Index 100 163 172 186 169 159 148

Referring to Table 2, in the case of the embodiment including the aramid short fibers surface-treated as compared to the comparative example showed the results of increased grip performance and wear. However, when using the surface-treated aramid short fibers in excess of 1.0 parts by weight it can be seen that the grip performance and wear is reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims (6)

100 parts by weight of styrene-butadiene rubber, and
0.1 to 2.5 parts by weight of aramid short fibers surface-treated with a polysulfide selected from the group consisting of a compound represented by the following formula (1) or a hydrate thereof and a compound represented by the following formulas (2) to (6)
And a rubber composition for a tire tread.
[Chemical Formula 1]

(In Formula 1, Me is an alkali metal, n is an integer of 1 to 10, m is an integer of 1 to 6)
(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(In the above formulas 2 to 6,
R ₁ and R ₂ are each independently selected from the group consisting of hydrogen, halogen, nitro, hydroxy, an alkyl group having 1 to 12 carbon atoms, alkoxy having 1 to 12 carbon atoms, and an aralkyl group having 1 to 12 carbon atoms,
M is an integer of 1 to 6) delete The method of claim 1,
The short aramid fibers have an average length of 1.4 to 3.0cm, the average diameter is 0.2 to 1.0mm rubber composition for a tire tread. The method of claim 1,
The short aramid fiber is a rubber composition for a tire tread surface-treated with 2.0 to 10.0 parts by weight of a compound represented by the following formula (1) or a hydrate thereof, and 5.0 to 7.5 parts by weight of polysulfide based on 100 parts by weight of the aramid short fibers. . The method of claim 1,
The rubber tread for the tire tread is a tire tread having a nitrogen adsorption specific surface area of 30 to 300 m ² / g, and further comprises 1 to 30 parts by weight of carbon black having a DBP (n-dibutyl phthalate) oil absorption of 60 to 300cc / 100g. Rubber composition for A tire manufactured using the rubber composition for tire tread according to any one of claims 1 and 3 to 5.