KR20130076302A - Rubber composition for tire belt topping and tire manufactured by using the same - Google Patents

Abstract

PURPOSE: A rubber composition is provided to reduce a topping gauge by improving the rigidity of a rubber, thereby reducing the hysteresis of the rubber and reducing energy loss during the rolling of a tire. CONSTITUTION: A rubber composition for tire belt topping comprises 100.0 parts by weight of a raw rubber and 0.01-10 parts by weight of an aramid short fiber pellet which consists of two or more twisted bundles of the aramid short fiber and a rubber inserted between the twisted aramid short fiber bundles. The aramid short fiber is surface-treated with a compound represented by chemical formula 1 or a hydrate thereof and a polysulfide. In chemical formula 1, Me is an alkali metal, n is an integer from 1-10, and m is an integer from 1-6.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a rubber composition for topping a tire belt,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a rubber composition for topping a tire belt and a tire made using the rubber composition, which can improve the rigidity of the rubber for belt topping and thereby reduce the topping gauge, thereby reducing the hysteresis of the rubber for belt topping, A rubber composition for topping a tire belt capable of reducing energy loss occurring during rotation, and a tire made using the rubber composition.

Generally, the middle part of a carcass to a tread is called a belt layer in a radial tire. The material of the belt layer is organic material and steel cord.

The belt is disposed at an angle close to a circle at the outer side of the tire, and a plurality of hard belt cords topped with a topping rubber are arranged in a stacked manner. The belt layer is a very important part as a strength layer in radial tires.

The steel cord constituting the belt is a double cord which forms a steel cord by densely twisting several filaments having a very small diameter, and a single cord which forms a steel cord with one filament of a large diameter. The steel cord formed by twisting a plurality of filaments penetrates between the gaps of the twisted steel cord and the bonding force between the topping rubber and the steel cord is good. However, the steel cord formed by the single wire has a relatively strong bonding force with the topping rubber There are low disadvantages.

The bonding force between the steel cord and the rubber to be topped has a great influence on the durability of the tire. The breakage of the actual tire starts by cracking due to weak bonding of the steel cord and the topping rubber surrounding the steel cord due to repetitive load applied to the tire and this crack grows and is connected to peeling of the steel cord and the topping rubber, It was one of the factors causing safety accidents.

Further, in order to improve the braking performance of the tire, it is necessary to reduce energy lost due to heat generated between the tire and the road surface. For this purpose, it is important to reduce the hysteresis generated in the rubber by reducing the content of the rubber constituting the tire. Thereby reducing the topping gauge of the belt by reducing the amount of rubber constituting the tire.

However, when the topping gauge of the belt is reduced, the problem of weakening the combination of the steel cord and the topping rubber can not be avoided.

Korean Patent Publication No. 2004-0043538 (Disclosure Date: April 24, 2004) 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)

It is an object of the present invention to provide a tire topping rubber which can reduce the topping gauge by improving the rigidity of the rubber for belt topping and thereby reduce the hysteresis of the rubber for belt topping, To provide a composition.

Another object of the present invention is to provide a tire produced by using the rubber composition for topping the tire belt.

In order to achieve the above object, a rubber composition for topping a tire belt according to an embodiment of the present invention comprises 100 parts by weight of raw rubber and 2 or more strands of aramid staple fibers, wherein the aramid staple fibers are infiltrated between the twisted aramid staple fibers 0.01 to 10 parts by weight of an aramid short fiber pellet comprising rubber.

The aramid staple fiber may be surface treated with a compound represented by the following formula (I) or a hydrate thereof and a polysulfide.

[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).

[Formula 2]

(3)

[Formula 4]

[Chemical Formula 5]

[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 aramid staple fibers may have an average length of 1 to 10 mm and an average diameter of 0.01 to 1.0 mm.

The aramid short fiber pellets may include 10 to 50 parts by weight of the infiltrated rubber with respect to 100 parts by weight of the aramid short fibers.

The rubber composition for topical tire belt has a nitrogen surface area per gram (N ₂ SA) of 100 to 200 m 2 / g and a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 100 to 200 m 2 / g And may further comprise 20 to 90 parts by weight of silica.

The tire according to another embodiment of the present invention is manufactured by using the rubber composition for topping the tire belt.

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

The rubber composition for topping a tire belt according to an embodiment of the present invention comprises 100 parts by weight of raw rubber and 2 or more strands of aramid short fibers and rubber infiltrated between the twisted aramid short fibers.

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.

The aramid staple fiber pellets are formed by twisting two or more strands of aramid staple fibers, and include rubber infiltrated between the twisted aramid staple fibers. The aramid staple fibers are formed by twisting aramid staple fibers having two or more strands, preferably two to ten strands, more preferably two to five strands.

The rubber infiltrated between the twisted aramid short fibers may be any one selected from the group consisting of natural rubber, synthetic rubber, and combinations thereof. The description of the natural rubber or synthetic rubber is the same as that described above for the raw rubber, and therefore, a detailed description thereof will be omitted. The rubber infiltrated between the twisted aramid short fibers preferably comprises the same components as the raw rubber, but the present invention is not limited thereto.

The rubber infiltrated between the twisted aramid staple fibers may be located in the hollow space of the center of the twisted aramid staple fibers or may be located between the bending of the twisted aramid staple fibers.

The aramid staple fiber pellets may be prepared by twisting two or more strands of aramid short fibers and then infiltrating the rubber composition between the twisted aramid short fibers or by making the twisted aramid short fibers dipped in a rubber composition, The aramid staple fibers may be twisted while the rod is centered and the rubber rod is wrapped.

The aramid short fiber pellets may contain 10 to 50 parts by weight, preferably 30 to 40 parts by weight of the infiltrated rubber with respect to 100 parts by weight of the aramid short fibers. If the content of the infiltrated rubber is less than 10 parts by weight, air entrainment may occur, and if it exceeds 50 parts by weight, short-fiber separation may occur.

The aramid staple fibers may have an average length of 1 to 10 mm, an average diameter of 0.01 to 1.0 mm, an average length of 4 to 5 mm, and an average diameter of 0.1 to 0.15 mm. If the average length of the aramid staple fibers is less than 1 mm, the content of the rubber covering the aramid staple fibers may be insufficient. If the average length of the aramid staple fibers exceeds 10 mm, the aramid staple fibers may not adhere to the rubber. If the average diameter of the aramid staple fibers is less than 0.01 mm, the aramid staple fibers may be broken due to lack of strength. If the aramid staple fibers have an average diameter exceeding 1.0 mm, the content of the belt cord may be insufficient.

The aramid short fiber pellets 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. If the content of the aramid short fiber pellets is less than 0.01 part by weight, the rigidity of the belt topping rubber may be lowered, and if it exceeds 10 parts by weight, cracks may occur in the belt topping rubber.

The aramid staple fiber may be surface treated with a compound represented by the following formula (I) or a hydrate thereof and a polysulfide.

Since the aramid short fibers surface-treated with the compound represented by the above-mentioned formula (1) or its hydrate and polysulfide are highly dispersible in rubber, they are uniformly distributed throughout the rubber for belt topping, thereby lowering the topping gauge have.

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.

[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).

[Formula 2]

(3)

[Formula 4]

[Chemical Formula 5]

[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 staple fiber is prepared by blending 1 to 2 parts by weight, preferably 1.55 to 1.65 parts by weight of the compound represented by the following formula 1 or its hydrate, and 1 to 2 parts by weight of the polysulfide with respect to 100 parts by weight of the aramid staple fiber , Preferably 1.45 to 1.55 parts by weight.

When the content of the compound represented by the formula (1) is less than 1 part by weight based on 100 parts by weight of the aramid short fibers, the aramid staple fibers may not be uniformly distributed in the rubber. When the amount exceeds 2 parts by weight Strand twisting of the aramid staple fibers can not be achieved. If the content of the polysulfide used in the surface treatment is less than 1 part by weight based on 100 parts by weight of the aramid short fibers, the aramid staple fibers may not be uniformly distributed in the rubber. When the amount of the aramid short fibers exceeds 2 parts by weight, Strand twist of staple fibers can not be achieved.

The rubber composition for topping the tire belt may further comprise silica as a filler. The silica may have a nitrogen surface area per gram (N ₂ SA) of 100 to 200 m 2 / g and a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 100 to 200 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, and if it exceeds 200 m & If the CTAB 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, and if it exceeds 200 m2 / g, the workability of the rubber composition may be deteriorated.

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. When the content of the silica is less than 20 parts by weight, the strength of the rubber may not be improved. When the content of the silica exceeds 90 parts by weight, cracks may be generated in the rubber.

The rubber composition for topping the tire belt may further include various additives such as additional vulcanizing agents, vulcanization accelerators, vulcanization accelerators, other fillers, coupling agents, anti-aging agents, softening agents or pressure-sensitive adhesives. The above-mentioned 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 the compounding ratio used in a rubber composition for topical tire belt topping.

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 rubber composition for topping the tire belt may further comprise a filler. The filler may be any one selected from the group consisting of carbon black, calcium carbonate, clay (hydrated aluminum silicate), aluminum hydroxide, lignin, silicate, talc, and combinations thereof.

The carbon black may have a nitrogen surface area per gram (N ₂ SA) of 30 to 300 m ² / g and an oil absorption amount of DBP (n-dibutyl phthalate) of 60 to 180 cc / 100 g, But is not limited thereto.

If the nitrogen adsorption specific surface area of the carbon black exceeds 300 m ² / g, the workability of the rubber composition for a tire may be deteriorated. If it is less than 30 m ² / g, the reinforcing performance by carbon black as a filler may be deteriorated. If the DBP oil absorption of the carbon black exceeds 180 cc / 100 g, the workability of the rubber composition may be deteriorated. If it is less than 60 cc / 100 g, the reinforcing performance by carbon black as a filler may be deteriorated.

Examples of the carbon black include N110, N121, N134, N220, N231, N234, N242, N293, N299, S315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 or N991.

The carbon black may be included in an amount of 30 to 80 parts by weight based on 100 parts by weight of the raw material rubber, preferably 45 to 65 parts by weight, and more preferably 53 to 57 parts by weight. When the content of the carbon black is less than 30 parts by weight, the reinforcing performance by the carbon black as a filler may decrease, and when the content of the carbon black exceeds 80 parts by weight, the processability of the rubber composition 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 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 low temperature characteristics and fuel consumption performance of the tire belt including the TDAE oil and cancer induction possibility of PAHs.

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 topping the tire belt 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 topping the tire belt is not limited to the tire belt portion but may be included in various rubber components constituting the tire. Said rubber components include treads (tread caps and tread bases), sidewalls, sidewall inserts, apex, chafer, wire coat or inner liner.

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

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 topping a tire belt of the present invention can reduce the topping gauge by improving the rigidity of the rubber for belt topping and thereby reduce the hysteresis of the rubber for topping the belt, .

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 belt topping according to the following Examples and Comparative Examples were prepared using the compositions shown in Table 1 below. The rubber composition was prepared according to a conventional method for preparing a rubber composition.

Unit: parts by weight Comparative Example 1 Example 1 Example 2 The first raw rubber ⁽¹⁾ 80 80 80 The second raw rubber ⁽²⁾ 20 20 20 Silica ⁽³⁾ 70 70 70 Oil ⁽⁴⁾ 25 25 25 Aramid
Staple fiber pellets ⁽⁵⁾ - One 2.5

(1) First raw rubber: solution polymerization styrene-butadiene rubber.

(2) Second raw rubber: butadiene rubber.

(3) Silica: nitrogen adsorption specific surface area of 150 m2 / g and CTAB adsorption specific surface area of 150 m2 / g.

(4) Oil: Ozone resistant oil.

(5) Aramid staple fiber pellets: aramid staple fibers having an average length of 4 mm and an average diameter of 0.125 mm and containing 100 parts by weight of a compound represented by the above formula (wherein Me is Na and m is 1 , and n is 6), and 1.5 parts by weight of a compound represented by the general formula (6) (R ₁ and R ₂ are hydrogen and m is 2) are kneaded, and then the twisted Prepared by infiltrating 35 parts by weight of rubber (solution polymerized styrene-butadiene rubber) between aramid staple fibers.

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.

- Hardness is measured with a Shore A type hardness meter. Hardness indicates steering stability. The higher the value, the better the steering stability.

100% and 300% modulus (kgf / ㎠): Modulus is the tensile strength at 100% or 300% elongation, measured according to ISO 37 standard.

- Wear loss (g): Wear loss amount is a Lambourn abrasion tester, which indicates the amount of worn rubber lost by rotating at a room temperature of 25% slip ratio at a load of 1.5 kg. The higher the value, the better the abrasion performance.

- tan δ was measured using ARES (10 Hz, 0.5% strain), and 60 ° C tan δ was favorable for rolling resistance as the value was lower, and the higher the value of 0 ° C tan δ, the better the braking performance.

Comparative Example 1 Example 1 Example 2 Hardness 69 71 72 100% modulus 8.23 9.29 9.99 300% modulus 121.3 139.2 144.3 Lambomb wear loss 1.009 0.799 0.891 0 C Tan δ 0.280 0.305 0.335 60 캜 Tan δ 0.102 0.098 0.098

Referring to Table 2, it can be seen that the braking performance was significantly improved in Examples 1 and 2, compared with Comparative Example 1, without wasting performance and loss of rotational resistance. Therefore, it can be seen that when the aramid short fiber pellets are added to the rubber composition for belt topping, the rigidity of the belt is increased.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (7)

100 parts by weight of raw rubber, and
0.01 to 10 parts by weight of aramid short fiber pellets comprising two or more strands of aramid short fibers twisted therein and comprising rubber impregnated between the twisted aramid short fibers
Rubber composition for tire belt topping comprising a. The short aramid fiber is a rubber composition for tire belt topping that is surface-treated with a compound represented by the following formula (1) or a hydrate and polysulfide thereof.
[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 method of claim 2,
The polysulfide is a rubber composition for a tire belt topping is 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]

(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) The method of claim 1,
Wherein the aramid staple fibers have an average length of 1 to 10 mm and an average diameter of 0.01 to 1.0 mm. The method of claim 1,
Wherein the aramid short fiber pellets comprise 10 to 50 parts by weight of the infiltrated rubber with respect to 100 parts by weight of the aramid short fibers. The method of claim 1,
The rubber composition for topical tire belt has a nitrogen surface area per gram (N ₂ SA) of 100 to 200 m 2 / g and a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 100 to 200 m 2 / g And 20 to 90 parts by weight of silica. A tire manufactured using the rubber composition for tire belt topping according to any one of claims 1 to 6.