Rubber composition and tire

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention is suitable for tire treads and the like, and when used in the tire tread, a rubber composition that satisfies ice skid performance, wet skid performance and wear resistance in a well-balanced manner, and ice skid performance and wet skid performance. It relates to a tire suitable as a pneumatic tire for all seasons, which has a good balance between tire tread and wear resistance.

【0002】

[Conventional technology]

Conventionally, a large amount of butadiene rubber and natural rubber have been used for tire treads for the purpose of improving tire grip performance (hereinafter referred to as "ice skid performance") during ice and snow. However, in this case, there is a problem that the tire grip performance (hereinafter referred to as "wet skid performance") in rainy weather is deteriorated. Therefore, for the purpose of improving the wet skid performance, silica is blended in the tire tread to increase the blending ratio of the silica. However, in this case, the tire tread has a problem that the wear resistance is lowered. At present, there is no tire tread that satisfies the ice skid performance, the wet skid performance, and the wear resistance at a sufficient level at the same time and can be suitably used for all seasons.

【0003】

[Problems to be Solved by the Invention]

An object of the present invention is to solve the above-mentioned conventional problems and to achieve the following object. That is, the present invention is suitable for a tire tread or the like, and when used in the tire tread, a rubber composition that satisfies the ice skid performance, the wet skid performance and the wear resistance in a well-balanced manner, and the ice skid performance and the wet It is an object of the present invention to provide a tire suitable as a pneumatic tire for all seasons by satisfying a good balance between skid performance and wear resistance.

【0004】

[Means for solving problems]

The means for solving the above-mentioned problems are as follows. That is, <1> 100 parts by weight of rubber component and surface treatment with silicon compound, specific surface area measured by mercury injection method is 100 ~ 250m²Surface-treated silica with / g of more than 0 parts by weight and less than 80 parts by weight, carbon black more than 0 parts by weight and less than 50 parts by weight, and at least one kind of aluminum oxide and aluminum hydroxide, more than 0 parts by weight and 30 parts by weight or less It is a rubber composition containing, and the surface-treated silica is contained in a larger amount than the carbon black. <2> The rubber component contains 40% by weight or more of a styrene-butadiene copolymer having a bonded styrene amount of 15 to 45% by weight and a vinyl bond amount of 7 to 60 mol% in the butadiene part in the above <1>. The rubber composition described. <3> The rubber composition according to <1> or <2> above, which contains 60% by weight or less of butadiene rubber containing 60 mol% or more of cis-1,4-structure. <4> The rubber composition according to any one of <1> to <3> above, wherein the surface-treated silica is surface-treated with 1 to 20 parts by weight of a silicon compound with respect to 100 parts by weight of silica. <5> The tire is characterized in that the rubber composition according to any one of <1> to <4> is used for the tread. <6> The tire according to <5>, which is a pneumatic tire. <7> The tire according to <5> or <6>, which is an all-season tire.

【0005】

BEST MODE FOR CARRYING OUT THE INVENTION

(Rubber Composition) The rubber composition of the present invention comprises a rubber component, surface-treated silica (hereinafter, simply referred to as "surface-treated silica") which is surface-treated with a silicon compound, carbon black, aluminum oxide and aluminum. It contains at least one hydroxide and further contains other components appropriately selected as needed.

【0006】

-Rubber component- The rubber component preferably contains a styrene-butadiene copolymer, and more preferably contains butadiene rubber.

【0007】

The styrene-butadiene copolymer may be a general one, but the amount of bonded styrene is 15 to 45% by weight, preferably 20 to 40% by weight, and the amount of vinyl bonded in the butadiene part is 7 to 60% by weight. It is preferably mol%, preferably 15 to 45 mol%.

【0008】

If the amount of bound styrene is less than 15% by weight, the wet skid performance may be deteriorated, and if it exceeds 45% by weight, the ice skid performance may be deteriorated. The amount of bound styrene can be calculated from the integration ratio of the H-NMR spectrum.

【0009】

If the vinyl bond amount of the butadiene portion is less than 7 mol%, the wet skid performance may be deteriorated, and if it exceeds 60 mol%, the ice skid performance may be deteriorated. The amount of vinyl bonds in the butadiene portion means the amount (mol%) of vinyl bonds present in the butadiene monomer units in the styrene-butadiene copolymer to which the 1st and 2nd forms are added. The vinyl bond amount can be measured by the infrared method (morero method).

【0010】

The styrene-butadiene copolymer may be used alone or in combination of two or more.

【0011】

The content of the styrene-butadiene copolymer in the rubber component is preferably 40% by weight or more, more preferably 55% by weight or more. If the content of the styrene-butadiene copolymer is less than 40% by weight, the wet skit performance may be insufficient.

【0012】

The butadiene preferably contains 60 mol% or more of the cis-1,4-structure. If the cis-1,4-structure is less than 60 mol%, the reinforcing property may be inferior. The ratio of the cis-1,4-structure can be calculated by the MORERO method with an infrared spectrophotometer, for example. The butadiene may be used alone or in combination of two or more.

【0013】

The content of the butadiene in the rubber component is preferably 60% by weight or less, more preferably 45% by weight or less. If the butadiene content exceeds 60% by weight, the wet skid performance may deteriorate.

【0014】

-Surface-treated silica-The surface-treated silica may be any as long as it is obtained by surface-treating ordinary silica with a silicon compound, and can be appropriately selected depending on the intended purpose, but the specific surface area measured by the mercury intrusion method. (PO) is 100 ~ 250m²Must be / g, 120 ~ 220m²It is preferably / g. The specific surface area (PO) measured by the mercury intrusion method is 100 m.²If it is less than / g, the wear resistance may be inferior, 250m²If it exceeds / g, the workability may be inferior.

【0015】

The specific surface area can be measured using, for example, a mercury intrusion meter such as a mercury porosimeter. Assuming that the pores in the silica are cylindrical, the following equation, specific surface area (PO) (m).²It can be calculated from / g) = 2VHg / r. However, in the above formula, V = total pore volume (ml / g) and r = average pore radius (μm).

【0016】

Nitrogen adsorption specific surface area (N) of the surface-treated silica₂As SA), 80 ~ 200m²/ g is preferred. The nitrogen adsorption specific surface area (N)₂SA) is 80m²If it is less than / g, the wear resistance may be inferior, 200m²If it exceeds / g, the workability may be inferior. The nitrogen adsorption specific surface area (N)₂SA) can be measured by the BET adsorption method and has a specific surface area of nitrogen adsorption per unit weight (m).²/ g) means.

【0017】

The surface-treated silica is preferably obtained by surface-treating 100 parts by weight of ordinary silica with 1 to 20 parts by weight of a silicon compound. If the amount of the silicon compound is less than 1 part by weight, the treatment effect may be small, and if it exceeds 20 parts by weight, an effect commensurate with it may not be obtained.

【0018】

The surface-treated silica is not particularly limited and may be appropriately selected depending on the intended purpose, and may be appropriately prepared or commercially available, but a wet one is preferable.

【0019】

The silicon compound is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a silane coupling agent, an alkoxysilane, a hydrogen atom, a hydroxyl group, a phenyl group, an amino group, an oxyalkylene group, a sulfur atom and the like. Examples thereof include alkylpolysiloxane, dialkylpolysiloxane, diphenylpolysiloxane, alkylalkoxysilane, phenylalkoxysilane, alkylhydroxysilane, phenylhydroxysilane, silazane, and the like.

【0020】

The silane coupling agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include vinylsilane, acrylicsilane, epoxysilane and aminosilane.

【0021】

Examples of the vinylsilane include vinyltriethoxysilane and vinyltrimethoxysilane. Examples of the acrylic silane include γ-methacryloxypropyltrimethoxysilane. Examples of the epoxy silane include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and the like. Examples of the aminosilane include N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and the like.

【0022】

Among the silane coupling agents, those having a sulfur atom in the molecule are preferable, and those represented by any of the following formulas (I) to (III) are more preferable.

【0023】

Equation (I) X_mY_3-mSi-ZS_n-Z-SiX_mY_3-mIn the formula (I), X represents an alkoxy group or a chlorine atom having 1 to 3 carbon atoms, preferably an alcohol group having 1 to 3 carbon atoms, and more preferably a methoxy group or an ethoxy group. Y represents an alkyl group having 1 to 3 carbon atoms. Z represents a saturated or unsaturated alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 12 carbon atoms. m represents an integer of 1 to 3, and 3 is preferable. n represents an integer of 1 or more, preferably 2 to 8, and may have a distribution.

【0024】

Specific examples of the silane coupling agent represented by the formula (I) include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, and bis (3-methyldimethoxysilyl). Propyl) tetrasulfide, bis (3-triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide , Etc. are preferably mentioned.

【0025】

Equation (II) X_mY_3-mSi-Z-SH In the above formula (II), X represents an alkyl group having 1 to 3 carbon atoms or a chlorine atom. Y represents a mercapto group. Z represents a saturated or unsaturated alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 12 carbon atoms. m represents an integer of 1 to 3, and 3 is preferable.

【0026】

Specific examples of the silane coupling agent represented by the formula (II) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, and the like. Be done.

【0027】

Equation (III) X_mY_3-mSi-ZS_n-A In the above formula (III), X represents an alkyl group having 1 to 3 carbon atoms or a chlorine atom. Y represents a mercapto group. A represents a benzothiazil group, an N, N-dimethylthiocarbamoyl group, or a methacryloyl group. Z represents a saturated or unsaturated alkylene group having 1 to 12 carbon atoms or an arylene group having 6 to 12 carbon atoms. m represents an integer of 1 to 3, and 3 is preferable. n represents an integer of 1 or more, preferably 2 to 8, and may have a distribution.

【0028】

Specific examples of the silane coupling agent represented by the above formula (III) include 3-trimethoxysilylpropyl-N, N-dimethylcarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-. Preferable examples include trimethoxysilylpropyl methacryloyl monosulfide.

【0029】

The silane coupling agent may be appropriately prepared or may be a commercially available product. The silane coupling agent may be used alone or in combination of two or more.

【0030】

Examples of the alkoxysilane include the same as those described for the silane coupling agent, and further, methyltrimethoxylane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. , N-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, n-octyltrimethoxysilane, n-dodecyltrimethoxysilane, n-dodecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane , Didimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and the like.

【0031】

The surface treatment method is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a predetermined amount of the silicon compound is added to ordinary known (unsurface-treated) silica. Then, a method of heat-treating after vigorously stirring can be mentioned.

【0032】

The content of the surface-treated silica in the rubber composition needs to be more than 0 parts by weight and 80 parts by weight or less with respect to 100 parts by weight of the rubber component, and is preferably 50 to 70 parts by weight. When the content of the surface-treated silica is 0 parts by weight, the effect of improving the wet skid performance is insufficient, and when it exceeds 80 parts by weight, the strength and abrasion resistance become insufficient, and static electricity Occurrence becomes remarkable.

【0033】

-Carbon black- The carbon black is not particularly limited and may be appropriately selected depending on the intended purpose. Specific examples thereof include SAF, GPF, FEF, HAF and ISAF, and among these, SAF is particularly preferable. .. The carbon black may be used alone or in combination of two or more.

【0034】

The content of the carbon black in the rubber composition needs to be more than 0 parts by weight and 50 parts by weight or less, preferably 5 to 15 parts by weight. If the content of the carbon black is 0 parts by weight, it may be inferior in terms of both coloring and reinforcing property, and if it exceeds 50 parts by weight, rolling resistance becomes large and it may not be suitable as an all-season tire.

【0035】

-Aluminum oxide and aluminum hydroxide- The aluminum oxide and the aluminum hydroxide are not particularly limited and may be appropriately selected depending on the intended purpose, but aluminum hydroxide is preferably used. Examples of the aluminum hydroxide include "Heidilite (trademark)" manufactured by Showa Denko KK. These may be used alone or in combination of two or more.

【0036】

The content of the aluminum oxide and the aluminum hydroxide in the rubber composition needs to be more than 0 parts by weight and 30 parts by weight or less, preferably 10 to 20 parts by weight. When the content of the aluminum oxide and the aluminum hydroxide is 0 parts by weight, the effect of improving the wet skid performance is not sufficient, and when it exceeds 30 parts by weight, the wear resistance is significantly lowered.

【0037】

In the rubber composition of the present invention, it is necessary that the surface-treated silica is contained in a larger amount than the carbon black. If the amount of the surface-treated silica is less than that of the carbon black, the wet skid performance cannot be ensured.

【0038】

-Other ingredients- As the other components, they can be appropriately selected and used within a range that does not impair the object of the present invention. For example, process oils, inorganic fillers, softeners, vulcanizers such as sulfur, dibenzothiazil disulfides, etc. Vulcanization accelerators such as, vulcanization aids, anti-aging agents such as N-cyclohexyl-2-benzothiazil-sulfenamide, N-oxydiethylene-benzothiazil-sulfenamide, zinc oxide, stearic acid, ozone deterioration inhibitor , Colorants, antistatic agents, lubricants, antioxidants, coupling agents, foaming agents, foaming aids and other additives, as well as various compounding agents usually used in the rubber industry. Commercially available products can be preferably used for these.

【0039】

The oil content of the process oil or the like is not particularly limited and may be appropriately selected depending on the intended purpose, but aromatic oil, naphthenic oil, paraffin oil, ester oil and the like are preferable. When an oil component such as the process oil is contained in the rubber composition, the fluidity of the rubber composition can be controlled, the viscosity of the rubber composition before vulcanization is lowered, and the fluidity is reduced. It is advantageous in that it can be enhanced and extrusion can be performed extremely well.

【0040】

-Manufacturing of rubber composition- The rubber composition of the present invention comprises the rubber component, the surface-treated silica, the carbon black, at least one of the aluminum oxide and the aluminum hydroxide, and the other components appropriately selected as necessary. Can be produced by kneading, heating, extrusion, vulcanization, or the like.

【0041】

The kneading conditions are not particularly limited, and are intended for various conditions such as the volume charged into the kneading device, the rotation speed of the rotor, the ram pressure, the kneading temperature, the kneading time, and the type of the kneading device. It can be appropriately selected accordingly. Examples of the kneading device include a Bunbury mixer (registered trademark), an intermix (registered trademark), a kneader, etc., which are usually used for kneading a rubber composition.

【0042】

The heating conditions are not particularly limited, and various conditions such as the heating temperature, the heating time, and the heating device can be appropriately selected according to the purpose. Examples of the heating device include a roll machine usually used for heating a rubber composition.

【0043】

The extrusion conditions are not particularly limited, and various conditions such as extrusion time, extrusion speed, extrusion apparatus, extrusion temperature and the like can be appropriately selected according to the purpose. Examples of the extruder include an extruder usually used for extrusion of a rubber composition for a tire. The extrusion temperature can be appropriately determined.

【0044】

The apparatus, method, conditions and the like for performing the vulcanization are not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the device for performing the vulcanization include a molding vulcanizer using a mold usually used for vulcanizing a rubber composition for a tire. As a condition of the vulcanization, the temperature is usually about 100 to 190 ° C.

【0045】

-Use- The rubber composition of the present invention is suitable for a tire tread, can be preferably used for an all-season tire tread, and can be particularly preferably used for the following tires of the present invention.

【0046】

(tire) The tire of the present invention is not particularly limited except that the rubber composition of the present invention is used for the tread, and a known tire configuration can be adopted as it is.

【0047】

As an example of the structure of the tire, a pair of bead portions, a carcass formed in a toroid shape connected to the bead portions, a structure having a belt and a tread for tightening the crown portion of the carcass, and the like are preferable. Listed in. The tire of the present invention may have a radial structure or a bias structure.

【0048】

The structure of the tread is not particularly limited, and may be a one-layer structure or a multi-layer structure, and is adjacent to the upper cap portion that directly touches the road surface and the inside of the tire of this cap portion. It may have a so-called cap base structure composed of a base portion of a lower layer arranged therein. In the present invention, it is preferable that at least the cap portion is formed of the rubber composition of the present invention.

【0049】

The tire of the present invention is not particularly limited in its manufacturing method, but can be manufactured as follows, for example. That is, first, the rubber composition of the present invention is prepared, and the rubber composition is attached onto an unvulcanized base portion previously attached to the crown portion of the tire case. Then, it can be produced by vulcanization molding with a predetermined mold under a predetermined temperature and a predetermined pressure.

【0050】

The tire of the present invention is suitably used for small vehicles such as passenger cars and light trucks, and large vehicles such as trucks and buses, and can be suitably used as pneumatic tires, nitrogen-containing tires, solid tires, and the like.

【0051】

[Example]

Hereinafter, examples of the tire of the present invention using the rubber composition of the present invention will be described, but the present invention is not limited to these examples.

【0052】

(Examples 1 to 4, target examples, and comparative examples 1 to 5) Four pneumatic tires (185 / 70R13 size) using the rubber composition shown in Table 1 for the tire tread are used for a passenger car with a displacement of 1600 cc. It was attached and the ice skid performance, wet skid performance and wear resistance were evaluated as follows. The results are shown in Table 1.

【0053】

<Ice skid performance> The ice skid performance is expressed as the braking performance on ice as an index. Braking performance on ice with ice temperatures of -1 ° C and -8 ° C was measured and expressed as an index by the following formula. Performance on ice = (braking distance of control tire (control example / braking distance of test tire) x 100 [0054]

<Wet skid performance> Wet skid performance is expressed as wet braking performance as an index. The braking distance from 80km / h was indexed for two passengers, and the control example was displayed as 100. The higher the value, the better the wet skid performance.

【0055】

<Abrasion resistance> The rubber composition of the tread of the pneumatic tire is cut out and used as a test piece, and the wear resistance of the test piece is measured at a temperature of 30 ° using a lambourn wear tester (manufactured by Iwamoto Seisakusho Co., Ltd.). The amount of wear loss was measured under the conditions of C and a slip ratio of 20%, and calculated by the following formula. Wear resistance index = {(wear loss amount of control example) / (wear loss amount of test piece)} × 100 The rubber composition of the control example was expressed as 100 as an exponential notation. The larger the value, the better the wear resistance.

【0056】

[table 1]

<img file="JP2002155166A_D0001.tif" />【0057】

In Table 1, the numerical values represent "parts by weight". "SBR1500" means styrene-butadiene rubber (manufactured by JSR Co., Ltd., SBR1500 , bound styrene amount 23.5% by weight, vinyl bound amount 18.9 mol%). "BR01" means butadiene rubber (manufactured by JSR Co., Ltd., BR01 , cis-1,4-structure content 96 mol%). "Carbon Black SAF" means (manufactured by Tokai Carbon Co., Ltd., Seest 9 , SAF). "Silica VN3" is wet silica (manufactured by Degussa AG, ULTRASIL VN3 (trademark), nitrogen adsorption specific surface area (N).₂SA) = 175m²/ g, which means the specific surface area (PO) = 160). "Surface-treated silica" is made by adding 500 g of hydrous silicic acid (manufactured by Degussa AG, ULTRASIL (registered trademark) VN3) and 15 g of silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF96) into a rotary kiln at 250 ° C. After being treated with silica for 10 minutes, it was allowed to cool to room temperature, and the specific surface area (PO) measured as shown below was 156 m.²It was / g. The specific surface area (PO) was measured by a mercury intrusion method using a mercury porosimeter (manufactured by Carlo Elba, 2000 type). "Silane coupling agent" means bis (3-triethoxysilylpropyl) -tetrasulfide (manufactured by Degussa AG, Si69 ). "Aluminum hydroxide" means Showa Denko KK Heidilite H-43M . "Aluminum oxide" means manufactured by Condea Japan Co., Ltd. "Oil" means FUKKOL ARMAX 3 (trademark) manufactured by Fuji Kosan Co., Ltd.

【0058】

[Effect of the invention]

According to the present invention, the above-mentioned problems in the prior art can be solved, and it is suitable for a tire tread or the like, and when it is used for the tire tread, it satisfies the ice skid performance, the wet skid performance and the wear resistance in a well-balanced manner. It is possible to provide a tire suitable as a pneumatic tire for all seasons by satisfying the rubber composition and the ice skid performance, the wet skid performance and the wear resistance in a well-balanced manner.