KR20130075456A - Rubber composition for tire tread and tire manufactured by using the same - Google Patents

Abstract

PURPOSE: A rubber composition for a tire thread is provided to improve grip performance at high speed traveling without the degradation of abrasion resistance and durability. CONSTITUTION: A rubber composition for a tire thread includes 100.0 parts by weight of a raw rubber, and 1-40 parts by weight of an aramid short fiber, the surface of which is treated with a hydroxyl group. The aramid short fiber carboxyl group is that 1.4-2.0 wt% of carboxyl groups on the surface of the aramid short fiber is substituted by the hydroxyl groups. The rubber composition additionally includes 1-30 parts by weight of a carbon black with a nitrogen absorption surface area of 30-300 m^2/g, DBP (n-dibutyl phthalate) and an absorption amount of 60-300 cc/100g.

Description

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

The present invention relates to a rubber composition for tire treads and a tire manufactured using the same. A rubber composition for tire treads that can improve grip performance at high speeds by inducing a faster grip performance than the conventional one without deteriorating wear resistance and durability. And it relates to a tire manufactured using the same.

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.

Meanwhile, in the conventional tire tread rubber, styrene-butadiene rubber having a high styrene content or increasing the filling amount of carbon black is used to improve grip performance. However, when the filling amount of carbon black increases, the weight of the tire increases and heat resistance and wear resistance decrease. In addition, when using styrene-butadiene rubber having a high styrene content, there is a problem in that the durability and wear resistance of the tread portion decrease.

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 provide a rubber composition for a tire tread that can improve the grip performance at high speed by inducing a faster grip performance compared to the conventional without reducing the wear resistance and durability.

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 includes 100 parts by weight of raw rubber, and 1 to 40 parts by weight of aramid short fibers whose surface is modified with a hydroxyl group.

In the aramid short fibers whose surface is modified with a hydroxyl group, 1.4 to 2.0 wt% of the carboxyl groups present on the surface of the aramid fibers may be substituted with the hydroxyl group.

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 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.

The weight ratio of the carbon black and the short aramid fiber modified with a hydroxyl group may be 1: 2.28 to 6.67.

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

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

The rubber composition for tire treads according to an embodiment of the present invention includes 100 parts by weight of raw rubber, and 1 to 40 parts by weight of aramid short fibers whose surface is modified with a hydroxyl group.

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

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

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

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

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

In particular, the raw material rubber, polyisoprene rubber, polybutadiene rubber, conjugated diene aromatic vinyl copolymer, nitrile conjugated diene copolymer, hydrogenated NBR, hydrogenated NBR, olefin rubber, ethylene-propylene rubber modified with maleic acid, butyl rubber , Copolymers of isobutylene with aromatic vinyl or diene monomers, acrylic rubbers, ionomers, halogenated rubbers and chloroprene rubbers can be preferably used.

In the aramid short fibers whose surface is modified with a hydroxyl group, 1.4 to 2.0% by weight of the carboxyl groups present on the surface of the aramid fibers may be substituted with the hydroxyl group. When the substitution of the hydroxyl group is less than 1.4% by weight of the carboxyl group present on the surface of the aramid fiber is substituted with the hydroxyl group, the effect of introducing the hydroxyl group into the short aramid fibers, the effect is minimal, more than 2.0% by weight of the carboxyl group When substituted with the hydroxyl group may cause a problem of inducing hyperhydration.

The surface-modified 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-modified 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 surface-modified aramid short fibers is less than 0.2mm, there may be a dispersion problem on the mixing mixture, and when it exceeds 1.0mm, after mixing, the rubber orientation (arranged in the same direction) is faster, compared to the conventional It can lead to cracks.

The surface-modified 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-modified 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 is excessively increased, which may cause problems during extrusion.

On the other hand, the surface-modified aramid short fibers are preferably mixed in the rubber composition in the form of a master batch in that it can further improve the dispersibility of the surface-modified aramid short fibers. When the surface-modified 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-modified 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 raw material rubber.

The master batch may be a master batch by mixing the surface-modified aramid short fibers and the raw rubber and filler, followed by drying. 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 this case, heat may be generated more due to the bonding between the raw material rubber and the surface-modified aramid short fibers.

The surface-modified aramid short fibers have a surface modified with a hydroxyl group to improve dispersibility in the rubber matrix and to improve affinity with fillers such as silica. Therefore, the surface-modified aramid short fibers are uniformly distributed in the first half of the tire tread so that the heat generation is evenly and rapidly progressed in the first half of the tread, leading to a faster grip performance than the conventional one, and to prevent deterioration of specific part properties. .

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 5 to 10 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.

In addition, the weight ratio of the carbon black and the aramid short fibers whose surface is modified with a hydroxyl group may be 1: 2.28 to 6.67, preferably 1: 2.28 to 3.16. When the weight ratio of the aramid short fibers whose surface to the carbon black is modified with a hydroxyl group is less than 2.28, the grip performance is increased by 1.2 times to 4.5 times while the grip performance is improved while the grip performance is improved at high speeds. Can be.

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 it is commonly used in the field of the present invention, the content thereof is not particularly limited, depending on the compounding ratio used in the conventional tire tread rubber composition.

As said vulcanizing agent, a sulfur type vulcanizing agent can be used preferably. The sulfur-based vulcanizing agents include inorganic vulcanizing agents such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S) and colloidal sulfur, tetramethylthiuram disulfide (TMTD) and tetraethyl. Organic vulcanizing agents such as tetraethyltriuram disulfide (TETD) and dithiodimorpholine can be used. Specifically, as the sulfur vulcanizing agent, a vulcanizing agent which produces elemental sulfur or sulfur, for example, amine disulfide, polymer sulfur, or the like can be used.

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

The vulcanization accelerator refers to an accelerator that promotes the rate of vulcanization or promotes delay in the initial vulcanization stage.

The vulcanization accelerators include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, xanthate and their Any one selected from the group consisting of a combination can be used.

Examples of the sulfenamide vulcanization accelerators include N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS), and N, N-dicyclohexyl. Any selected from the group consisting of -2-benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, N, N-diisopropyl-2-benzothiazolesulfenamide and combinations thereof The sulfenamide type compound of can be used.

Examples of the thiazole vulcanization accelerators include 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), sodium salt of 2-mercaptobenzothiazole and zinc salt of 2-mercaptobenzothiazole. , Copper salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-di Any thiazole compound selected from the group consisting of ethyl 4-morpholinothio) benzothiazole and combinations thereof can be used.

Examples of the thiuram-based vulcanization accelerators include tetramethyl thiuram disulfide (TMTD), tetraethyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram disulfide, dipentamethylene thiuram monosulfide and dipentamethylene. Any thiuram-based compound selected from the group consisting of thiuram tetrasulfide, dipentamethylene thiuram hexasulfide, tetrabutyl thiuram disulfide, pentamethylene thiuram tetrasulfide, and combinations thereof can be used.

As the thiourea vulcanization accelerator, for example, thiocarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea, and any combination thereof is selected from the group of thiourea Compounds can be used.

As the guanidine-based vulcanization accelerator, for example, any one guanidine-based compound selected from the group consisting of diphenylguanidine, diorthotolylguanidine, triphenylguanidine, orthotolylbiguanide, diphenylguanidine phthalate, and combinations thereof can be used. Can be.

Examples of the dithiocarbamic acid-based vulcanization accelerators include ethylphenyldithiocarbamate zinc, butylphenyldithiocarbamate zinc, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, Zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate, zinc salt of pentamethylenedithiocarbamate and piperidine, hexadecylisopropyldithiocarbamate zinc, octadecyl Isopropyldithiocarbamate zinc dibenzyldithiocarbamate zinc, sodium diethyldithiocarbamate, pentamethylenedithiocarbamate piperidine, dimethyldithiocarbamate selenium, diethyldithiocarbamate tellurium, dia One dithiocarbamic acid compound selected from the group consisting of cadmium didicarbamate and combinations thereof can be used.

The aldehyde-amine-based or aldehyde-ammonia based vulcanization accelerator, for example, acetaldehyde-aniline reactant, butylaldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant and combinations thereof -Amine based or aldehyde-ammonia based compounds can be used.

As said imidazoline type vulcanization accelerator, imidazoline type compounds, such as 2-mercaptoimidazoline, can be used, for example, As said xanthate type vulcanization accelerator, xanthate type, such as zinc dibutyl xanthogenate Compounds can 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 and rubber properties by promoting the vulcanization rate.

The vulcanization accelerator is a compounding agent used in combination with the vulcanization accelerator to complete its promoting effect. Any one selected from the group consisting of inorganic vulcanization accelerators, organic vulcanization accelerators and combinations thereof can be used. .

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. The organic vulcanization accelerator is selected from the group consisting of stearic acid, zinc stearate, palmitic acid, linoleic acid, oleic acid, lauric acid, dibutyl ammonium oleate, derivatives thereof, and combinations thereof. You can use either one.

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 tire tread rubber composition 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, and a sulfide-based silane compound may be preferably used.

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

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

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

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

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

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

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

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.

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

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

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

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

The 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 step of thermomechanical treatment or kneading at a maximum temperature ranging from 110 to 190 ° C., preferably from 130 to 180 ° C. and the crosslinking system is mixed, typically less than 110 ° C., for example It can be prepared in a suitable mixer using a second step of mechanical treatment at a low temperature of 40 to 100 ℃, but the present invention is not limited thereto.

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. Such rubber components include sidewalls, sidewall inserts, apex, chafers, wire coats or innerliners, and the like.

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

The tire may be a passenger car tire, a racing tire, an airplane tire, a farm tire, an off-the-road 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.

The rubber composition for tire treads of the present invention may improve grip performance at high speeds by inducing a faster grip performance than the conventional one without deteriorating wear resistance and durability.

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]

Using a composition as shown in Table 1 below to prepare a rubber composition for tire treads according to the following examples and comparative examples. The rubber composition was prepared according to a conventional method for preparing a 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 5.7 5.7 5.7 5.7 5.7 5.7 Reinforcement ⁽³⁾ - 38.0 33.0 28.0 23.0 18.0 13.0 Zinc oxide 3.0 Stearic acid 1.0 brimstone 1.0 accelerant 2.5 Accelerator (DPG) 2

(1) Raw material rubber: styrene-butadiene 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) Reinforcing materials: Aramid short fibers, in which 1.5% by weight of the carboxyl groups present on the surface are modified with hydroxyl groups (average length is 2.6 cm, average diameter is 0.8 mm).

Experimental Example: Measurement of Physical Properties of Prepared 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.

Pattern viscosity (ML1 + 4 (125 ° C.)) was measured according to ASTM standard D1646.

- Hardness was measured by DIN 53505

- 300% Modulus was measured according to ISO 37 standard.

- The viscoelasticity was measured by using an RDS measuring instrument at a temperature of -60 ° C to 80 ° C at a frequency of 10 Hz at a strain of 0.1%.

Comparative example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 ML1 + 4 (125 ° C) 71 83 85 88 79 75 78 Shore A 82 67 72 75 77 83 90 300% Modulus (Mpa) 53.5 48.4 53.5 54.7 59.3 73.5 75.4 0 ℃ tan δ 0.2868 0.3031 0.3308 0.3269 0.3463 0.3558 0.4057 60 ℃ tan δ 0.2504 0.2554 0.2644 0.2638 0.2641 0.2649 0.2748

Referring to Table 2, the rubber compositions prepared in Examples 1 to 6 can be seen that the 0 ° C tan δ and 60 ° C tan δ values overall increase compared to the rubber composition prepared in Comparative Examples. In particular, the rubber compositions prepared in Examples 5 and 6 were able to obtain very improved results even at hardness and 300% modulus.

Through this, when the surface-modified aramid short fibers are included, it is confirmed that the early heating characteristics can be improved while securing durability, and the braking performance on the wet road surface is also very advantageous.

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 (6)

100 parts by weight of raw rubber, and
1 to 40 parts by weight of aramid short fibers whose surface is modified with a hydroxyl group
And a rubber composition for a tire tread. The method of claim 1,
The aramid short fibers whose surface is modified with a hydroxyl group is a rubber composition for tire treads 1.4 to 2.0% by weight of the carboxyl groups present on the surface of the aramid fiber is substituted with the hydroxyl group. 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 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 5. The method of claim 4,
The weight ratio of the carbon black and the aramid short fibers whose surface is modified with a hydroxyl group is 1: 2.28 to 6.67 rubber composition for tire tread. A tire manufactured using the rubber composition for tire tread according to any one of claims 1 to 5.