KR101749931B1 - 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 produced using the same, wherein the rubber composition for a tire tread has a glass transition temperature (Tg) of -50 to -40 캜, a Mooney viscosity of 60 to 80, 10 to 30mol% of epoxidized natural rubber and a Mooney viscosity with respect to the raw material rubber 100 parts by weight containing 35 to 55 of neodymium hatred butadiene rubber, CTAB value of from 120 to 220m ² / g, BET value of 140 to 250m ² / g 20 to 80 parts by weight of silica; 5 to 20 parts by weight of carbon black having an iodine adsorption of 50 to 150 mg / g and a DBPA oil absorption of 100 to 200 cc / 100 g; And 2 to 20 parts by weight of a coupling agent, it is possible to improve the anti-wear performance and the braking force on the wet road surface in a balanced manner, together with the reduction of the rotation resistance of the tire.

Description

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

The present invention relates to a rubber composition for a tire tread capable of improving the abrasion resistance and the braking force on a wet road surface together with a decrease in the rotation resistance of the tire, and a tire made using the rubber composition.

In tires, the tread is actually the part that touches the ground and is a major part of determining the main performances such as fuel consumption, wet road braking force, and abrasion resistance. Especially, in the case of tire tread for truck-bus, due to the characteristics of being subjected to high load, durability and wear resistance performance are important because a large amount of heat and large frictional force are applied.

On the other hand, Europe and countries are emphasizing the improvement of braking power on the low fuel consumption and wet road surface of the tire through the labeling system when the interest in the environment friendly industry is heightened around the world. In accordance with these trends, styrene-butadiene rubber and silica have been used for environmentally friendly tires for passenger cars. However, in the case of truck-bus tires, it has been difficult to use synthetic rubber and silica because of the aforementioned durability and abrasion resistance.

Generally, since each performance of a tire has a property of being tread-off, it is not easy to balance the rotation resistance of the tire with the braking force on the wet road surface and the durability and abrasion resistance performance.

For example, in order to improve durability and abrasion resistance of a tire, there has been proposed a method of using carbon black as a filler together with natural rubber in a rubber composition for a tire tread. In this case, however, grip performance on a wet road surface and fuel economy are disadvantageous there was. A method of using silica to improve the wet road surface braking force of the rubber composition for a tire tread has been proposed, but there is a disadvantage that the abrasion performance is relatively decreased when silica is used. In addition, when epoxidized natural rubber (ENR) is used as raw material rubber, there is a disadvantage that durability which is directly connected with the life of a tire for a truck-bus becomes disadvantageous, and a method of adding polybutadiene rubber as a method for improving abrasion resistance However, in the case of polybutadiene rubber, it is necessary to selectively use polybutadiene rubber because it may be disadvantageous to wet road surface braking force depending on the synthesis method and raw material properties.

Accordingly, it is required to develop a rubber composition for a tire tread which can simultaneously improve the fuel consumption performance of the tire and the braking force and the wear resistance performance on the wet road surface.

Korean Patent Publication No. 2011-0071607 (Publication date: June 29, 2011)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rubber composition for a tire tread which can solve the above-mentioned problems and improve the abrasion resistance and the braking force on a wet road surface together with a decrease in the rotation resistance of the tire.

Another object of the present invention is to provide a tire produced by using the rubber composition for tire tread with improved fuel consumption performance.

In order to achieve the above object, the rubber composition for a tire tread according to an embodiment of the present invention has a glass transition temperature (Tg) of -50 to -40 캜, a Mooney viscosity of 60 to 80, and an epoxy degree of 10 to 30 mol% A cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 120 to 220 m ² / g and a BET (Brunauer-Emmett) ratio of 100 parts by weight of a raw rubber comprising an epoxidized natural rubber and a neodymium butadiene rubber having a Mooney viscosity of 35 to 55 -Teller) 20 to 60 parts by weight of silica having a specific surface area of 140 to 250 m ² / g; 5 to 20 parts by weight of carbon black having an iodine adsorption value of 50 to 150 mg / g and a DBPA (n-dibutyl phthalate absorption) amount of 100 to 200 cc / 100 g; And 2 to 20 parts by weight of a coupling agent.

In the rubber composition, the epoxidized natural rubber may be contained in an amount of 70 to 100% by weight based on the total weight of the raw rubber.

Wherein the neodymium butadiene rubber has a Mooney viscosity of 35 to 55, a weight average molecular weight of 2.5 x 10 ⁵ to 4.0 x 10 ⁵ g / mol and a molecular weight distribution of 1.5 to 2.5, and the neodymium butadiene rubber is contained in an amount of 10 to 30 By weight.

The coupling agent may be Bis (3- (triethoxysilyl) propyl) tetrasulfide: TESPT).

The rubber composition for tire tread according to claim 1, wherein the rubber composition for tire tread comprises 0.5 to 5 parts by weight of a vulcanizing agent, 0.1 to 10 parts by weight of a vulcanization accelerator, 1 to 10 parts by weight of a vulcanization accelerator, 1 to 50 parts by weight of a softening agent, 10 to 10 parts by weight of a pressure-sensitive adhesive, 0.5 to 10 parts by weight of a pressure-sensitive adhesive, and a mixture thereof.

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.

In the present invention, a raw material rubber containing an epoxidized natural rubber (ENR) obtained by epoxidizing a natural rubber is used, and silica and carbon black having optimized physical properties as a filler are used in respective optimum amounts, The rubber composition for a tread is characterized in that the rotation resistance of the tire is reduced and the abrasion resistance and the braking force on the wet road surface are balanced in a balanced manner.

That is, the rubber composition for a tire tread according to an embodiment of the present invention comprises an epoxidized natural rubber having a glass transition temperature (Tg) of -50 to -40 캜, a Mooney viscosity of 60 to 80 and an epoxidation degree of 10 to 30 mol% And neodymium butadiene rubber having a Mooney viscosity of 35 to 55, 5 to 20 parts by weight of carbon black having an iodine adsorption of 50 to 150 mg / g and a DBPA content of 100 to 200 cc / 100 g; 20 to 80 parts by weight of silica having a CTAB value of 120 to 220 m ² / g and a BET value of 140 to 250 m ² / g; And 2 to 20 parts by weight of a coupling agent.

Each component will be described in detail below.

In the rubber composition for a tire tread of the present invention, the raw rubber includes Epoxidized Natural Rubber (ENR).

The epoxidized natural rubber (ENR) is an epoxidized unsaturated double bond of natural rubber (NR). The epoxidized natural rubber (ENR) is an environmentally-friendly, polar epoxy group and increases its molecular cohesive strength. , Mechanical strength and abrasion resistance. The epoxy group of the epoxidized natural rubber can react with the silanol group on the surface of the silica to improve the mechanical strength and abrasion resistance of the rubber composition, and can remarkably increase the braking force particularly on the wet road surface.

Specifically, the epoxidized natural rubber preferably has an epoxidation degree of 10 to 30 mol%. The degree of epoxidation refers to the number of epoxidized double bonds / (number of double bonds before epoxidation). If the degree of epoxidation of the epoxidized natural rubber is less than 10 mol%, it is difficult to obtain the effect of using the silica due to the reduced reactivity with silica, and if it exceeds 30 mol%, scorch may occur due to the ring opening reaction of the epoxidized natural rubber. As a result, the vulcanization rate becomes excessively high, and there is a possibility that the extrusion processability is lowered due to the scorch.

The epoxidized natural rubber (ENR) preferably has a glass transition temperature (Tg) of -50 to -40 캜 and a Mooney viscosity of 60 to 80 along with the degree of epoxidation. If the above glass transition temperature condition is not satisfied or the Mooney viscosity range condition is not satisfied, there is a fear that the braking force, abrasion resistance and workability on the wet road surface are lowered.

The epoxidized natural rubber preferably has an epoxidation degree of 15 to 25 mol%, a glass transition temperature (Tg) of -50 to -40 DEG C, a Mooney viscosity of 60 to 60 DEG C, 70 < / RTI >

The above-mentioned epoxidized natural rubber (ENR) may be commercially available or may be an epoxidized natural rubber (NR). The method of epoxidizing natural rubber is not particularly limited, and conventional epoxidation methods such as chlorohydrin method, direct oxidation method, hydrogen peroxide method, alkyl hydroperoxide method, peracid method and the like can be used. For example, in the case of the over-acid method, the reaction can be carried out by reacting natural rubber with organic acids such as peracetic acid and formic acid.

The epoxidized natural rubber may be contained in an amount of 70 to 100% by weight based on the total weight of the starting rubber. If the content of the epoxidized natural rubber is less than 70 parts by weight, the effect of addition of the epoxidized natural rubber is insignificant.

In order to improve abrasion resistance and fuel economy, the raw material rubber should have a Mooney viscosity of 35 to 55, a weight average molecular weight of 2.5 x 10 ⁵ to 4.0 x 10 ⁵ g / mol and a molecular weight distribution of 1.5 to 2.5 in addition to the epoxidized natural rubber. Butadiene rubber. The neodymium butadiene rubber may not contain oil.

The butadiene rubber can use various catalysts according to the preparation method. Neodymium butadiene rubber (Nd-BR) produced by using Neodymium (Nd) catalyst is superior to butadiene rubber produced by using cobalt or nickel catalyst. is superior to other butadiene rubbers in terms of abrasion resistance and heat resistance since it has a high cis- content, a high molecular weight, a low glass transition temperature and a low branching degree, i.e., high molecular chain linearity. In particular, since the neodymium-butadiene rubber has high molecular weight and high linearity of the molecular chain, it can compensate for the decrease in wear resistance due to the use of silica and improve the fuel-efficiency performance.

In the present invention, the neodymium butadiene rubber having a high molecular weight and a high molecular weight distribution with a narrow molecular weight distribution as described above is used to provide a nickel catalyst butadiene rubber having a molecular weight distribution of 2.5 to 3.5, The abrasion resistance can be effectively improved as compared with the rubber.

When the neodymium butadiene rubber as described above is contained in the raw rubber, it may be preferable that the neodymium butadiene rubber is included in an amount of 10 to 20% by weight based on the total weight of the raw rubber in terms of improvement in fuel consumption performance. If the content of the neodymium butadiene rubber is less than 10% by weight, the effect of improving the wear performance by the use of the neodymium butadiene rubber is insignificant, and if it exceeds 20% by weight, the workability may be lowered.

The raw material rubber may further comprise a natural rubber or a modified natural rubber or synthetic rubber other than the epoxidized natural rubber.

The natural rubber can be used as long as it is generally known as natural rubber, and the place 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. Examples of the modified natural rubber include deproteinized natural rubber (DPNR), hydrogenated natural rubber, and the like.

The synthetic rubber may be at least one selected from the group consisting of styrene butadiene rubber (SBR), modified styrene butadiene rubber, butadiene rubber (BR), modified butadiene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, fluorine rubber, silicone rubber, (NBR), modified nitrile butadiene rubber, chlorinated polyethylene rubber, styrene ethylene butylene styrene (SEBS) rubber, ethylene propylene rubber, ethylene propylene diene (EPDM) rubber, hyaluron rubber, chloroprene rubber, ethylene Vinyl acetate rubber, acrylic rubber, hydrin rubber, vinyl benzyl chloride styrene butadiene rubber, bromomethyl styrene butyl rubber, maleic styrene butadiene rubber, carboxylic styrene butadiene rubber, epoxy isoprene rubber, ethylene ethylene propylene rubber, Butadiene rubber, Rommie Ney suited polyisobutyl isoprene-co-p-methylstyrene may be a (brominated polyisobutyl isoprene-co-paramethyl styrene, BIMS), and one selected from the group consisting of.

The content of the natural rubber, drawn natural rubber or synthetic rubber is not particularly limited and may be appropriately included within a range that does not deteriorate the effect of the rubber composition for a tire tread according to the present invention.

In addition, the rubber composition for a tire tread includes silica and carbon black as a reinforcing filler.

It is preferable that the silica has a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 120 to 220 m ² / g and a BET (Brunauer-Emmett-Teller) specific surface area of 140 to 250 m ² / g. The CTAB adsorption specific surface area and BET specific surface area conditions of silica are required to be satisfied simultaneously. Even if the BET specific surface area is satisfied, if the CTAB adsorption specific surface area of the silica is less than 120 m2 / g, The performance may be deteriorated. On the other hand, if it exceeds 220 m 2 / g, the workability of the rubber composition may be deteriorated. When the BET specific surface area value of silica is less than 140 m ² / g, the reinforcing property is deteriorated. When the BET specific surface area value is more than 250 m ² / g, the physical properties and workability of the tire are deteriorated .

Ultrasil 7000Gr (Evonik), Ultrasil 9000Gr (Evonik), Zeosil 1165MP (Rhodia), Zeosil 200MP (Rhodia), and the like can be used as the commercially available silica. Or Zeosil 195HR (manufactured by Rhodia).

The silica may be contained in an amount of 20 to 80 parts by weight based on 100 parts by weight of the raw rubber, more preferably 30 to 60 parts by weight, and further preferably 40 to 50 parts by weight. When the content of the silica is less than 20 parts by weight, the strength of the rubber is not improved and the braking performance of the tire may be deteriorated. When the content of the silica is more than 80 parts by weight, the abrasion performance may be deteriorated.

In addition, the carbon black is used together with silica for enhancing the reinforcing performance of tread rubber in tires and for black coloring of tread rubber.

The carbon black preferably has an iodine adsorption of 50 to 150 mg / g and a DBPA (n-dibutyl phthalate absorption) of 100 to 200 cc / 100 g. If the DBPA value of the carbon black exceeds 200 cc / 100 g in a condition satisfying all the other physical property requirements except for DBPA, the processability of the rubber composition is lowered On the other hand, if the DBPA value is less than 50 cc / 100 g, the reinforcing performance by the carbon black as a filler may be deteriorated.

The carbon black may be selected from the group consisting of N110, N121, N134, N220, N231, N234, N242, N293, N299, S315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N582, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 or N991.

It is preferable that such carbon black is used in a lower content than silica. The reinforcing performance of the rubber composition may be deteriorated if it is used in an amount equal to or higher than that of silica. Specifically, it is preferable that the carbon black is included in an amount of 5 to 20 parts by weight based on 100 parts by weight of the raw rubber. When the content of carbon black is less than 5 parts by weight, the effect of using carbon black is insignificant. When the content of carbon black is more than 20 parts by weight, the workability of the rubber composition may decrease. Also, considering the remarkable improvement effect, it is more preferable that the carbon black is included in 5 to 10 parts by weight with respect to 100 parts by weight of the raw rubber.

The CTAB and BET specific surface area of the silica and the iodine adsorption value and DBPA value of the carbon black are physical properties affecting the workability, low rolling resistance performance, abrasion resistance and endurance performance of the rubber composition for tire tread, The effects according to the present invention can be obtained when the requirements are simultaneously satisfied. If any of these physical property requirements is not satisfied, it is difficult to obtain the improvement effect on the physical properties of the rubber composition.

The rubber composition for a tire tread includes a coupling agent for reaction with the silica.

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

Among them, bis (3- (triethoxysilyl) propyl) tetrasulfide: TESPT may be more preferable

The coupling agent may be included in an amount of 2 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 2 parts by weight, the improvement of the dispersibility of the silica may be insufficient and the rubber workability may deteriorate or the fuel-combustion performance may deteriorate. If the content of the coupling agent is more than 20 parts by weight, May be excellent, but the braking performance may be very poor. In addition, if a coupling agent that has not reacted with silica remains in the rubber composition, the physical properties of the rubber composition may be deteriorated.

In addition to the above-mentioned components, the rubber composition for a tire tread according to the present invention is optionally used for improving the physical properties of rubber compositions for tire treads, such as vulcanizing agents, vulcanization accelerators, vulcanization accelerators, softening agents, The additive may be added singly or in combination of two or more.

Specifically, as the vulcanizing agent, a metal oxide such as a sulfur vulcanizing agent, an organic peroxide, a resin vulcanizing agent, or a magnesium oxide can be 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. In addition, vulcanizing agents which produce elemental sulfur or sulfur such as amine disulfide, polymer sulfur Etc. may be used.

Also, the organic peroxide is selected from the group consisting of benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5- (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5- Butylperoxybenzene, di-t-butylperoxy-diisopropylbenzene, t-butylperoxybenzene, 2,4-dichlorobenzoylperoxide, 1,1-dibutylperoxy- 3,3,5-trimethylsiloxane, or n-butyl-4,4-di-t-butylperoxyvalerate.

It is preferable that the vulcanizing agent is included in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the raw material rubber from the viewpoint that the raw rubber 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 0.1 to 10 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. Examples of the organic-based vulcanization accelerator include stearic acid, zinc stearate, palmitic acid, linoleic acid, oleic acid, lauric acid, dibutyl ammonium oleate, derivatives thereof, You can use 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 to produce favorable sulfur during the vulcanization reaction Thereby facilitating the crosslinking reaction of the rubber.

When zinc oxide and stearic acid are used together, it is preferable to use 1 to 10 parts by weight per 100 parts by weight of the raw material rubber in order to serve as an appropriate vulcanization accelerating auxiliary.

The softening agent is added to the rubber composition in order to impart plasticity to the rubber to facilitate processing or to reduce the hardness of the vulcanized rubber, and means a processing oil used for rubber compounding or rubber production. 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 3 wt% or more together with the increase in environmental consciousness, Treated distillate aromatic extract (TDAE) oil, mild extraction solvate (MES) oil, residual aromatic extract (RAE) oil or heavy naphthenic oil.

Particularly, the oil used as the softener preferably has a total content of PAHs components of 3% by weight or less, a kinematic viscosity of 95 ° C or more (210 ° F. SUS), an aromatic component in the softener of 15 to 25% A TDAE oil having 27 to 37% by weight of a component and 38 to 58% by weight of a paraffin 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.

Examples of the vegetable oil 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 1 to 50 parts by weight based on 100 parts by weight of the raw material rubber in order to improve the workability of the raw material rubber.

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

Examples of the amine type antioxidant include N-phenyl-N '- (1,3-dimethyl) -p-phenylenediamine, N- (1,3-dimethylbutyl) -N'- Phenyl-N'-isopropyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, -Cyclohexyl p-phenylenediamine, N-phenyl-N'-octyl-p-phenylenediamine, and combinations thereof.

Examples of the phenolic antioxidant include phenol-based 2,2'-methylene-bis (4-methyl-6-tert-butylphenol), 2,2'- isobutylidene- Di-t-butyl-p-cresol, and combinations thereof.

As the quinoline antioxidant, 2,2,4-trimethyl-1,2-dihydroquinoline and its derivatives can be used. Specifically, 6-ethoxy-2,2,4-trimethyl- Dihydroquinoline, 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline and combinations thereof Any one selected from the group can be used.

As the wax, waxy hydrocarbons can be preferably used.

Considering the conditions such that the antioxidant has a high solubility in rubber, a low volatility, an inertness to rubber, and no inhibition of vulcanization, it is preferable that the antioxidant is used in an amount of 0.1 to 10 parts by weight, By weight.

The pressure-sensitive adhesive further improves the tack performance between the rubber and the rubber and improves the physical properties of the rubber by improving the mixing properties, dispersibility and processability of other additives such as fillers.

As the pressure-sensitive adhesive, a natural resin-based pressure-sensitive adhesive such as a rosin-based resin or a terpene-based resin and a synthetic resin-based pressure-sensitive adhesive such as a petroleum resin, a coal tar, or an alkylphenolic resin can be used.

The rosin-based resin may be any one selected from the group consisting of rosin resins, rosin ester resins, hydrogenated rosin ester resins, derivatives thereof, and combinations thereof. The terpene resin may be any one selected from the group consisting of terpene resin, terpene phenol resin, and combinations thereof.

Wherein the petroleum resin is selected from the group consisting of an aliphatic resin, an acid-modified aliphatic resin, an alicyclic resin, a hydrogenated alicyclic resin, an aromatic (C9) resin, a hydrogenated aromatic resin, a C5-C9 copolymer resin, a styrene resin, And a combination thereof.

The coal tar may be a coumarone-indene resin.

The alkylphenol resin may be a p-tert-alkylphenol formaldehyde resin and the p-tert-alkylphenol formaldehyde resin may be a p-tert-butyl-phenol formaldehyde resin, p-tert- And a combination thereof.

The pressure-sensitive adhesive may be included in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the raw material rubber. If the amount of the pressure-sensitive adhesive is less than 0.5 parts by weight based on 100 parts by weight of the raw material rubber, the adhesion performance is poor. If the amount is more than 10 parts by weight, rubber properties may be deteriorated.

The rubber composition for a tire tread may be prepared by mixing the above-mentioned components according to a conventional method. During the finishing step in which the first step of thermo-mechanical treatment or kneading and the crosslinking system are mixed, specifically 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, but the present invention is not limited thereto.

The rubber composition for a tire tread produced by the above method has a combination constitution including the raw material rubber including the epoxidized natural rubber together with the silica and the carbon black in which the physical property requirements are optimized, The anti-wear performance and the braking force on the wet road surface can be improved along with the reduction of the rotation resistance of the tire. Accordingly, the rubber composition for a tire tread is not limited to a tread (a tread cap and a tread base), and may be included in various rubber components constituting the tire. Said rubber components include sidewalls, sidewall inserts, apex, chafer, wire coat or inner liner.

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

The tire may be manufactured from the rubber composition for a tire tread as described above and exhibit a balanced wettability performance, a low rolling resistance performance, and a durability performance in combination with an improved wet road surface braking force.

The method of manufacturing the tire may be any method used for manufacturing a tire except for the use of the rubber composition for tire tread, and a detailed description thereof will be omitted herein. However, the tire may include a tire tread made using the rubber composition for a tire tread.

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 a tire tread according to the present invention improves the braking force on the wet road surface of the tire and improves the durability performance in a balanced manner with the low rolling resistance performance without deteriorating the abrasion resistance.

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.

Example  And Comparative Example : tire For tread  Preparation of rubber composition

Were mixed in the compositions and contents as shown in Table 1 below, and mixed in a Banbury mixer to prepare a rubber composition for a tire tread.

Example 1 Comparative Example 1 Example 2 Example 3 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 ENR ¹ 100 100 90 100 100 - 100 100 100 100 ENR-A ² - - - - - 100 - - - - BR ³ - - 10 - - - - - - - Silica ⁴ 60 60 60 50 - 60 - 60 60 60 Silica-A ⁵ - - - - - - 60 - - - Carbon black ⁶ 5 5 5 5 50 5 5 - 5 - Carbon Black-A ⁷ - - - - - - - 5 - - Coupling agent ⁸ 5 - 5 5 5 5 5 5 30 5 Processing oil 5 5 5 5 5 5 5 5 5 5 Zinc oxide 2 2 2 2 2 2 2 2 2 2 Stearic acid One One One One One One One One One One Vulcanizing agent
(brimstone) One One One One One One One One One One Vulcanization accelerator ⁹ 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6

1. ENR 25: ENR with an epoxidization degree of 25 mol%, a glass transition temperature (Tg) of -45 ° C and a Mooney viscosity of 60 to 80

2. ENR 50: ENR with an epoxidization degree of 50 mol%, a glass transition temperature (Tg) of -23 DEG C and a Mooney viscosity of 60 to 80

3. BR: Butadiene rubber (average molecular weight = 2.5 ~ 4.0x10 ⁵ g / mol) prepared by neodymium catalyst.

4. Silica: precipitated silica having a CTAB value of 160 m ² / g and a BET of 175 m ² / g

5. Silica-A: precipitated silica having a CTAB value of 230 m ² / g and a BET of 255 m ² / g

6. Carbon black: Carbon black having an iodine adsorption value of 82 mg / g and a DBPA value of 102 cc / 100 g

7. Carbon black-A: Carbon black having an iodine adsorption of 160 mg / g and a DBPA value of 210 cc /

8. Coupling agent: Bis (3- (triethoxysilyl) propyl) tetrasulfide: TESPT) Bis (3- (triethoxysilyl)

9. Vulcanization accelerator: CBS (N-cyclohexyl-2-benzothiazoyl sulfonamide)

Test Example : Measurement of physical properties

The rubber specimens were prepared using the rubber composition for tire tread prepared in the above Examples and Comparative Examples 1 to 4, and the rubber specimens thus prepared were evaluated for various physical properties according to the ASTM regulations. The results are shown in Table 2 below.

(1) The Mooney viscosity (ML1 + 4 (125 캜)) was measured using a Mooney MV2000 (Alpha Technology) apparatus on a large rotor, preheating for 1 minute, rotor operating time of 4 minutes, and temperature of 125 캜. The Mooney viscosity means that the higher the value, the greater the viscosity of the rubber, indicating that the workability is disadvantageous.

(2) The hardness was measured using a Shore A hardness meter.

(3) The 300% modulus is the tensile strength at 300% elongation, measured according to ISO 37 standard. The higher the value, the better the strength.

(4) Tensile properties were measured using an Instron tester according to ASTM D412.

(5) The wet performance index was measured by the method of ISO 15222, and the index of Example 1 was expressed as 100 based on the measurement. Wet performance means that the larger the value, the better the performance.

(6) The LRR figure of merit was measured by the method of ISO 28580, and the index of Example 1 was set to 100 and indexed based on it. The larger the LRR performance, the better the performance.

(7) The abrasion resistance index was expressed by indexing on the basis of 100 as Example 1 after measuring the abrasion amount under a slip rate of 25% by using a rambone abrasion tester. The wear resistance performance means that the higher the value, the better the performance.

Example 1 Comparative Example 1 Example 2 Example 3 Comparative Example
2 Comparative Example
3 Comparative Example
4 Comparative Example
5 Comparative Example
6 Comparative Example
7 Mooney viscosity (ML1 + 4 (125 DEG C) 78 95 82 65 41 80 105 74 62 70 Hardness (Shore A) 63 72 70 63 62 65 76 61 55 57 300% modulus
(kgf / cm2) 108 154 137 103 126 119 102 105 90 100 Tensile properties
(Toughness) 394 240 433 333 417 367 401 390 562 405 Wet performance index 100 102 98 99 89 105 99 96 87 97 LRR performance index 100 105 107 107 122 102 82 103 76 108 Wear resistance performance index 100 91 109 102 116 85 94 95 80 82

As shown in Table 2, the rubber composition of the examples exhibited a balanced balance of mechanical properties such as abrasion resistance and braking force on the wet road surface as well as reduction of the rotational resistance of the tire, The rubber composition of Example 2, which was a mixture of dimethylbutadiene rubber, exhibited excellent wear resistance performance with excellent mechanical properties. From these results, it can be seen that the rotational resistance of the rubber composition of Example 2 is greatly improved due to the reduction of heat generation. In the case of the rubber composition of Example 3 in which the content of silica is somewhat lower than that of the Examples, the braking force on the wet road surface was slightly lowered and the rolling resistance and the abrasion resistance performance were improved. On the other hand, Which is superior to the conventional method.

On the other hand, the rubber composition of Comparative Example 1, which did not use a coupling agent, exhibited reduced workability and abrasion resistance. In addition, the rubber composition of Comparative Example 4 using carbon black in an excess amount without using silica had excellent LRR and abrasion resistance, but the braking force, rotation resistance characteristic, and wet performance on the wet road surface were greatly degraded.

From the experimental results, it can be confirmed that the rubber composition of the example including the rubber composition for tire tread according to the present invention has a balanced balance of antiwear wear performance and braking force on a wet road surface in addition to reduction in rotation resistance of the tire. It can be understood that the optimum combination of the rubber composition according to the present invention must be satisfied in order to obtain the effects of the present invention.

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)

An epoxidized natural rubber having a glass transition temperature (Tg) of -50 to -40 占 폚, a Mooney viscosity of 60 to 80 and an epoxidation degree of 10 to 30 mol%, and a neodymium butadiene rubber having a Mooney viscosity of 35 to 55 With respect to 100 parts by weight of the rubber,
20 to 80 parts by weight of silica having an adsorption specific surface area of CTAB (cetyl trimethyl ammonium bromide) of 120 to 160 m ² / g and a BET (Brunauer-Emmett-Teller) specific surface area of 140 to 175 m ² / g,
5 to 20 parts by weight of carbon black having an iodine adsorption value of 50 to 150 mg / g and a DBPA (n-dibutyl phthalate absorption) amount of 100 to 200 cc / 100 g,
And 2 to 20 parts by weight of a coupling agent,
The epoxidized natural rubber is contained in an amount of 70 to 90% by weight based on the total weight of the raw rubber,
Wherein the neodymium butadiene rubber has a Mooney viscosity of 35 to 55, a weight average molecular weight of 2.5 x 10 ⁵ to 4.0 x 10 ⁵ g / mol and a molecular weight distribution of 1.5 to 2.5, and the neodymium butadiene rubber is contained in an amount of 10 to 30 By weight,
Wherein the coupling agent is bis (3- (triethoxysilyl) propyl) tetrasulfide: TESPT)
Rubber composition for tire tread. delete delete delete The method according to claim 1,
The rubber composition for tire tread according to claim 1, wherein the rubber composition for tire tread comprises 0.5 to 5 parts by weight of a vulcanizing agent, 0.1 to 10 parts by weight of a vulcanization accelerator, 1 to 10 parts by weight of a vulcanization accelerator, 1 to 50 parts by weight of a softening agent, 10 to 10 parts by weight of a tackifier, 0.5 to 10 parts by weight of a tackifier, and a mixture thereof. A tire produced by using the rubber composition for a tire tread according to claim 1.