JP2020019834A - Rubber composition and pneumatic tire - Google Patents

Abstract

To provide a rubber composition having excellent workability, wear resistance, fuel economy and breaking strength, and a pneumatic tire including the same.SOLUTION: This invention relates to a rubber composition containing, based on a rubber component 100 pts.mass, carbon black of 2-200 pts.mass that has a hydrogen release rate of 0.20 mass% or more and a nitrogen adsorption specific surface of 160-190 m/g.SELECTED DRAWING: None

Description

The present invention relates to a rubber composition and a pneumatic tire using the same.

In recent years, with the demand for safety and low fuel consumption of automobiles, simultaneous improvement of wear resistance and low fuel consumption has been desired for rubber materials for tires.

Conventionally, in order to solve such a problem, a method of using fine particle carbon black capable of imparting high reinforcement and excellent wear resistance has been implemented (for example, Patent Documents 1 and 2). reference).

However, in general, the use of fine carbon black has room for improvement in that there is a tendency that the processability is deteriorated due to an increase in the viscosity of the rubber composition, and the dispersibility of the filler is thereby reduced. .

International Publication No. 2014/181776 WO 2014/189102

An object of the present invention is to solve the above problems and to provide a rubber composition having good processability, abrasion resistance, low fuel consumption and breaking strength, and a pneumatic tire using the same.

The present inventors have conducted intensive studies on a method for solving the above-mentioned problems, and as a result, by using a specific carbon black, good workability, abrasion resistance, low fuel consumption and breaking strength (in particular, abrasion resistance and (Rupture strength) was obtained, and reached the present invention.
That is, the present invention relates to a rubber composition containing 2 to 200 parts by mass of carbon black having a hydrogen release rate of 0.20% by mass or more and a nitrogen adsorption specific surface area of 160 to 190 m ² / g based on 100 parts by mass of a rubber component. About things.

The carbon black is preferred oil absorption due to compression is 90~150cm ³ / 100g.

The carbon black preferably has a maximum frequency Stokes equivalent diameter of 50 to 100 nm.

The carbon black preferably has a Stokes equivalent diameter half width of 30 to 90 nm.

The rubber composition is preferably a rubber composition for a tire.

The present invention also relates to a pneumatic tire having a tread manufactured using the above rubber composition.

According to the present invention, since it is a rubber composition containing a specific carbon black, it has good workability, abrasion resistance, low fuel consumption and breaking strength, and is excellent in abrasion resistance, low fuel consumption and breaking strength. Pneumatic tires can be provided.

The rubber composition of the present invention is obtained by adding ² parts of carbon black having a hydrogen release rate of 0.20% by mass or more and a nitrogen adsorption specific surface area (N ₂ SA) of 160 to 190 m ² / g to 100 parts by mass of the rubber component. ２００200 parts by mass. Thereby, good workability, wear resistance, low fuel consumption, and breaking strength can be obtained. The reason why such an effect is obtained is not necessarily clear, but is presumed as follows.

According to the study by the present inventors, it has been found that the hydrogen release rate of carbon black and N ₂ SA have the following tendencies.
It relates N 2 _SA specific surface area, the carbon black into fine particles, increasing the N ₂ SA specific surface area of the carbon black increases the interaction with the polymer, the reinforcing property is improved. The hydrogen release rate is an indicator of the surface activity of carbon black, and the higher the hydrogen release rate, the higher the surface activity. It is known that when the surface of carbon black is highly activated, the dispersion of carbon black in the compounded rubber is improved. For this reason, it was presumed that the improvement of the dispersion of the carbon black in the compounded rubber due to the high activation of the carbon black surface and the fineness of the carbon black would make it possible to achieve both low fuel consumption and abrasion resistance. However, contrary to expectation, when N ₂ SA exceeds 190 [m ² / g], the effect of improving the carbon black dispersion due to the high activation of the carbon black surface is reduced due to the deterioration of workability, and the expected fuel economy is expected. It was found that no improvement could be obtained. If the N ₂ SA is less than 160 [m ² / g], the processability is good, and the reduction in the effect of improving the carbon black dispersion due to the high activation of the carbon black surface is small. It was found that the abrasion resistance was reduced, and no dramatic improvement in performance from conventional carbon black could be obtained.
On the other hand, in the present invention, the effect of improving the dispersion of carbon black due to the high activation of the carbon black surface is sufficiently obtained by the appropriate micronization, and `` the carbon black in the compounded rubber is enhanced by the high activation of the carbon black surface. Dispersion improvement "and" Improvement of reinforcing properties by making carbon black finer "enhances the reinforcing properties synergistically, and provides good workability, abrasion resistance, low fuel consumption, and rupture strength. In particular, wear resistance is improved.

In the present invention, by setting the N ₂ SA of the carbon black to 160 to 190 m ² / g, the effect of blending the highly activated carbon black having a hydrogen release rate of 0.20% by mass or more is sufficiently achieved. It is considered that the reinforcement is synergistically improved while exhibiting good workability, abrasion resistance, low fuel consumption, and breaking strength.

(Rubber composition)
The rubber composition contains carbon black (1) having a hydrogen release rate of 0.20% by mass or more and a nitrogen adsorption specific surface area of 160 to 190 m ² / g. Carbon black (1) may be used alone or in combination of two or more.

The hydrogen release rate of carbon black (1) is 0.20% by mass or more, preferably 0.21% by mass or more. The upper limit is not particularly limited, but is preferably 0.50% by mass or less, more preferably 0.30% by mass or less. When the hydrogen release rate is within the above range, the effect can be suitably obtained.
In the present specification, the hydrogen release rate of carbon black was determined by placing carbon black dried in a constant-temperature dryer at 105 ° C. for 1 hour to room temperature in a desiccator, and then placing the carbon black in a sample tube made of tin. The amount of hydrogen gas generated when heated at 2,000 ° C. for 15 minutes under an argon gas flow with a hydrogen analyzer was measured and expressed in terms of mass fraction.

Nitrogen adsorption specific surface area of the carbon black ₍₁₎ (N 2 SA) is may be a 160~190m ² / g, is preferably 165m ² / g or more, more preferably 170m ² / g or more, It is preferably at most 185 m ² / g, more preferably at most 180 m ² / g. When the N ₂ SA specific surface area is within the above range, the effect is suitably obtained.
In this specification, _N 2 SA of carbon black, JIS K 6217-2: determined by 2001.

Dibutyl phthalate (DBP) oil absorption of the carbon black (1) is preferably 100 cm ^3/100 g or more, more preferably 120 cm ^3/100 g or more, further preferably 135 cm ^3/100 g or more, and preferably 200 cm ³ / 100g or less, more preferably 170cm ³ / 100g, more preferably not more than 155cm ³ / 100g. When it is within the above range, the effect can be more suitably obtained.
In the present specification, the DBP lubrication amount of carbon black is a value measured according to JIS K6217-4: 2001.

Oil absorption by the compression of carbon black (1) (COAN) is preferably 90cm ^3/100 g or more, more preferably 100 cm ^3/100 g or more, further preferably 110 cm ^3/100 g or more, and preferably 150 cm ³ / 100g or less, more preferably 140cm ³ / 100g, more preferably not more than 135 cm ³ / 100g. When COAN is within the above range, the effect can be more suitably obtained.
In addition, in this specification, COAN of carbon black is a value measured using dibutyl phthalate according to JIS K 6217-4: 2001.

The specific surface area of cetyltrimethylammonium bromide (CTAB) of carbon black (1) is preferably at least 110 m ² / g, more preferably at least 130 m ² / g, even more preferably at least 140 m ² / g, and preferably at least 190 m ² / g. ² / g or less, more preferably 170 m ² / g or less, and even more preferably 155 m ² / g or less. When the CTAB specific surface area is within the above range, the effect can be more suitably obtained.
In the present specification, the CTAB specific surface area of carbon black is a value measured according to JIS K6217-3: 2001.

The maximum frequency Stokes equivalent diameter (D _mod ) of the carbon black (1) is preferably at least 50 nm, more preferably at least 60 nm, further preferably at least 75 nm, and preferably at most 100 nm, more preferably at most 98 nm, furthermore Preferably it is 95 nm or less. D _mod is a typical size of the aggregate of carbon black, and when D _mod is within the above range, the effect can be more suitably obtained.

The Stokes equivalent diameter _half width (D _1/2 ) of the carbon black (1) is preferably at least 30 nm, more preferably at least 50 nm, further preferably at least 65 nm, and preferably at most 90 nm, more preferably at most 85 nm. And more preferably 80 nm or less. D _1/2 is an index indicating the spread of the aggregate size distribution of the carbon black. When D _1/2 is within the above range, the effect can be more suitably obtained.

In this specification, D _mod and D _1/2 are values measured by the following method.
A precisely weighed carbon black sample is added to a 20% aqueous ethanol solution to which a surfactant ("NONIDET P-40" manufactured by SIGMA CHEMICAL) has been added to prepare a sample solution having a carbon black concentration of 0.01% by mass. The liquid is subjected to a dispersion treatment for 5 minutes at a vibration frequency of 200 kHz and an output of 100 W using an ultrasonic dispersing machine (“Ultrasonic generator USV-500V” manufactured by Ultrasonic Industry) to prepare a carbon black slurry. 10 ml of a spin solution (pure water) was injected into a sedimentation type particle size distribution analyzer (“BI-DCP PARTICLSIZER” manufactured by BROOK HAVEN INSTRUMENTS), and 1 ml of a buffer solution (20% ethanol aqueous solution) was further injected. 1m each of the prepared carbon black slurry Liter was injected and centrifuged down at 10,000 rpm to measure the Stokes equivalent diameter and create a histogram of the frequency of occurrence relative to the Stokes equivalent diameter, parallel to the Y axis passing through the peak (A) of the histogram. The intersection of the straight line and the X-axis of the histogram is defined as C. The Stokes diameter at this C is defined as the maximum frequency Stokes equivalent diameter (D _mod ). The intersection (D, E) of two points between the straight line G parallel to the axis and the distribution curve of the histogram is obtained, and the absolute value of the difference between the Stokes diameters of D and E is calculated as the Stokes equivalent diameter _half- width value (D _1/2 ). And

The content of the carbon black (1) may be 2 to 200 parts by mass with respect to 100 parts by mass of the rubber component, but is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 20 parts by mass or more. It is at least 30 parts by mass, particularly preferably at least 30 parts by mass, preferably at most 150 parts by mass, more preferably at most 100 parts by mass, even more preferably at most 80 parts by mass. When the content of carbon black (1) is within the above range, the effect can be more suitably obtained.

In the rubber composition, a carbon black other than the carbon black (1) may be used together with the carbon black (1). In this case, the total content of carbon black may be the same as the case where the carbon black (1) is used alone.

The carbon black (1) can be manufactured by a person skilled in the art by a known manufacturing method once the target characteristics are determined. Although the production method is not particularly limited, specifically, it is preferable to adopt a method of producing carbon black by spraying a raw material oil into a combustion gas, for example, a conventionally known method such as a furnace method or a channel method. Is used. Especially, the furnace method shown below is preferable.

In the furnace method (oil furnace method), for example, as disclosed in JP-A-2004-43598 and JP-A-2004-277443, a raw material is added to a combustion zone in which a high-temperature combustion gas flow is generated in a reaction furnace and a high-temperature combustion gas flow. A process using a device having a reaction zone for introducing hydrocarbons to convert raw material hydrocarbons into carbon black by a pyrolysis reaction, and a reaction stop zone for quenching the reaction gas to stop the reaction. By controlling various conditions such as the flow rate of the combustion gas, the conditions for introducing the raw material oil into the reaction furnace, and the time from the conversion of carbon black to the termination of the reaction, carbon black having various characteristics can be produced.

In the combustion zone, air, oxygen, or a mixture thereof and gaseous or liquid fuel hydrocarbon are mixed and combusted as an oxygen-containing gas to form a high-temperature combustion gas. As the fuel hydrocarbon, petroleum-based liquid fuels such as carbon monoxide, natural gas, coal gas, petroleum gas, and heavy oil, and coal-based liquid fuels such as creosote oil are used. Preferably, the combustion is controlled so that the combustion temperature is in the range of 1400C to 2000C.

In the reaction zone, the raw hydrocarbon is spray-injected from a burner provided in parallel or in a lateral direction to the high-temperature combustion gas flow obtained in the combustion zone, and the raw hydrocarbon is thermally decomposed to be converted into carbon black. Preferably, the feed oil is introduced into the high temperature combustion gas stream having a gas flow rate in the range of 100 to 1000 m / s by one or more burners. It is preferable that the feed oil is divided and introduced by two or more burners. Further, it is preferable to provide a throttle section in the reaction zone in order to improve the reaction efficiency. The ratio of the diameter of the constricted portion to the diameter of the constricted portion upstream region is preferably 0.1 to 0.8.

In the reaction stop zone, water spray or the like is performed to cool the high-temperature reaction gas to 1000 to 800 ° C or lower. The time from the introduction of the feedstock oil to the termination of the reaction is preferably from 2 to 100 msec. After being cooled and separated from the gas, the cooled carbon black can be subjected to a known process such as granulation and drying.

Specific examples of the feedstock oil include (1) aromatic hydrocarbons such as anthracene; coal-based hydrocarbons such as creosote oil; EHE oil (replicated oil at the time of ethylene production); FCC oil (fluid catalytic cracking residual oil). And (2) aliphatic hydrocarbons and at least one selected from the group consisting of petroleum heavy oils. These may be modified. Above all, a mixed feedstock of coal-based hydrocarbon and aliphatic hydrocarbon is preferred.

As the aliphatic hydrocarbon, for example, petroleum-based aliphatic hydrocarbons represented by process oils, and animal and vegetable oils represented by fatty acids such as soybean oil, rapeseed oil, and palm oil can be used.
Here, animal and vegetable oils include fatty oils (liver oil) obtained from fish liver, marine animal oils such as sea animal oil obtained from whales, and terrestrial animal oils such as tallow and lard, plant seeds, fruits and nuclei. It contains fats and oils containing fatty acid glyceride as a component.

Examples of the rubber component that can be used include diene rubbers such as isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), and styrene isoprene butadiene rubber (SIBR). The rubber components may be used alone or in combination of two or more. Among them, SBR, BR, and isoprene-based rubber (particularly, isoprene-based rubber) are preferable because effects can be more suitably obtained, and isoprene-based rubber, a combination of SBR and BR, or a combination of isoprene-based rubber and BR Is more preferred.

The SBR is not particularly limited, and for example, an emulsion-polymerized styrene-butadiene rubber (E-SBR), a solution-polymerized styrene-butadiene rubber (S-SBR), or the like can be used. These may be used alone or in combination of two or more.

The BR is not particularly limited. For example, BR having a high cis content, BR containing a syndiotactic polybutadiene crystal, or the like can be used. These may be used alone or in combination of two or more. Among them, the cis content of BR is preferably 90% by mass or more because of good abrasion resistance.

SBR and BR may be modified.
The modified SBR and the modified BR may be any as long as they have a functional group that interacts with a filler such as carbon black. For example, at least one terminal of the polymer is modified with a compound having the above functional group (a modifying agent). Terminal modified rubber (terminal modified rubber having the above functional group at the terminal), main chain modified rubber having the above functional group in the main chain, or main chain terminal modified rubber having the above functional group in the main chain and terminal (for example, Modified with a main chain terminal-modified BR having the functional group in the main chain and at least one terminal modified with the modifying agent) or a polyfunctional compound having two or more epoxy groups in the molecule. And a terminal-modified rubber into which a hydroxyl group or an epoxy group is introduced. These may be used alone or in combination of two or more.

Examples of the functional group include, for example, amino group, amide group, silyl group, alkoxysilyl group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, mercapto group, sulfide group, disulfide Group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group and the like. . Note that these functional groups may have a substituent. Among them, an amino group (preferably an amino group in which a hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms) and an alkoxy group (preferably having 1 carbon atom) are preferable because the effect can be more suitably obtained. And an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms).

As SBR and BR, for example, products such as Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Zeon Corporation can be used.

When SBR is contained, the content of SBR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 45% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass. %, More preferably 65% by mass or less. When the content is in the above range, the effect tends to be more favorably obtained.

When BR is contained, the content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass. %, More preferably 30% by mass or less. When the content is in the above range, the effect tends to be more favorably obtained.

Examples of the isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified natural rubber, modified NR, modified IR, and the like. As the NR, for example, a general NR in the tire industry, such as SIR20, RSS # 3, and TSR20, can be used. The IR is not particularly limited, and for example, a general IR in the tire industry such as IR2200 can be used. As modified natural rubber, high-purity natural rubber (UPNR) or the like, modified NR as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, or the like; Examples include isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, and the like. These may be used alone or in combination of two or more. Among them, natural rubber (NR) is preferred.

When the isoprene-based rubber is contained, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and particularly preferably 20% by mass or more. % By mass or more. Further, it is preferably at most 95% by mass, more preferably at most 90% by mass, still more preferably at most 85% by mass, particularly preferably at most 80% by mass. When SBR is contained, the content is more preferably 60% by mass or less, particularly preferably 40% by mass or less. When the content is in the above range, the effect tends to be more favorably obtained.

The rubber composition may include a resin.
In this specification, a resin means a polymer compound, more specifically, a polymer obtained by polymerizing a monomer unit, and may be a solid or a liquid.
The resin is not particularly limited as long as it is generally used in the tire industry. For example, polyalkylene resin, coumarone indene resin, α-methylstyrene resin, terpene resin, acrylic resin, C5 resin And a C9 resin. These may be used alone or in combination of two or more. Among them, polyalkylene resins and terpene resins are preferable because rubber can be plasticized, the dispersion of the filler can be promoted, and the effect can be more suitably obtained.

The polyalkylene resin is not particularly limited as long as it has a unit derived from alkylene, and includes, for example, polyethylene resin, polypropylene resin, polybutylene resin, ethylene propylene resin, ethylene propylene styrene resin, ethylene styrene resin, propylene styrene resin, and the like. Is mentioned. Among them, ethylene propylene resin and ethylene propylene styrene resin are preferable.

The terpene-based resin is not particularly limited as long as it has a unit derived from a terpene compound. For example, polyterpene (resin obtained by polymerizing terpene compound), terpene aromatic resin (terpene compound and aromatic compound) And a modified aromatic terpene resin (a resin obtained by modifying a terpene resin with an aromatic compound).

The terpene compound is a hydrocarbon represented by the composition of (C ₅ H ₈ ) _n and its oxygen-containing derivative, and is a monoterpene (C ₁₀ H ₁₆ ), a sesquiterpene (C ₁₅ H ₂₄ ), a diterpene (C ₂₀ H). ₃₂ ) Compounds having a basic skeleton of a terpene classified as, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-pherandrene, α-terpinene, γ-terpinene, Examples include terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol. Examples of the terpene compound also include resin acids (rosin acid) such as abietic acid, neoabietic acid, parastolic acid, levopimaric acid, pimaric acid, and isopimaric acid. That is, the terpene-based resin also includes a rosin-based resin mainly composed of rosin acid obtained by processing rosin. Examples of the rosin resin include naturally occurring rosin resins (polymerized rosin) such as gum rosin, wood rosin, and tall oil rosin, as well as modified rosin resins such as maleic acid-modified rosin resin and rosin-modified phenol resin, and rosin glycerin esters. Examples include rosin esters and disproportionated rosin resins obtained by disproportionating rosin resins.

The aromatic compound is not particularly limited as long as it is a compound having an aromatic ring, and examples thereof include phenol compounds such as phenol, alkylphenol, alkoxyphenol, and phenols containing unsaturated hydrocarbon groups; naphthol, alkylnaphthol, alkoxynaphthol, Naphthol compounds such as naphthol containing a saturated hydrocarbon group; and styrene derivatives such as styrene, alkylstyrene, alkoxystyrene and styrene containing an unsaturated hydrocarbon group. Of these, styrene is preferred.

The softening point of the resin is preferably 0 ° C or higher, more preferably 10 ° C or higher, even more preferably 40 ° C or higher. The softening point is preferably 160 ° C. or lower, more preferably 140 ° C. or lower, even more preferably 100 ° C. or lower. When it is within the above range, the effect can be more suitably obtained.
In the present specification, the softening point of the resin is a temperature at which a sphere falls when a softening point specified in JIS K 6220-1: 2001 is measured by a ring and ball softening point measuring device.

The resin may be a hydrogenated resin, and it is preferable that the resin is a hydrogenated hydrogenated resin because the effect is more suitably obtained. The hydrogenation can be performed by a known method. For example, any of catalytic hydrogenation using a metal catalyst and a method using hydrazine can be suitably used (Japanese Patent Application Laid-Open No. Sho 59-161415). For example, catalytic hydrogenation with a metal catalyst can be carried out by adding hydrogen under pressure in an organic solvent in the presence of a metal catalyst, and the organic solvent is preferably tetrahydrofuran, methanol, ethanol, or the like. Can be used for These organic solvents can be used alone or in combination of two or more. Further, as the metal catalyst, for example, any of palladium, platinum, rhodium, ruthenium, nickel and the like can be suitably used. These metal catalysts can be used alone or in combination of two or more. . The pressure at the time of pressurization is preferably, for example, 1 to 300 kgf / cm ² .

In the above resin, the hydrogenation rate of the double bond is 1 to 100%, particularly preferably 2% or more, more preferably 5% or more, and still more preferably 8% or more. . Further, the upper limit of the hydrogenation rate of the double bond, in the hydrogenation reaction, the heating conditions under pressure, and advances in production technology such as catalysts, there is a possibility that its preferred range can be changed by improving productivity, etc. Although it has not been confirmed accurately at this time, at present, for example, it is preferably 80% or less, more preferably 60% or less, still more preferably 40% or less, even more preferably 30% or less. Particularly preferred is 25% or less.
The hydrogenation rate (hydrogenation rate) is a value calculated from the integrated values of the peaks derived from double bonds by ¹ H-NMR (proton NMR) according to the following formula. In this specification, the hydrogenation rate (hydrogenation rate) means the hydrogenation rate of double bonds.
(Hydrogenation rate [%]) = {(AB) / A} × 100
A: Integrated value of double bond peak before hydrogenation B: Integrated value of double bond peak after hydrogenation

As the resin, for example, Mitsui Chemicals, Inc., Stractol, Yashara Chemical, Arizona Chemical, Nisshin Chemical, Rutgers Chemicals, Arakawa Chemical, Maruzen Petrochemical, Products such as Sumitomo Bakelite Co., Ltd., Tosoh Co., Ltd., Nippon Shokubai Co., Ltd., JX Energy Co., Ltd. and Toagosei Co., Ltd. can be used.

When a resin is contained, the content of the resin is preferably at least 1 part by mass, more preferably at least 3 parts by mass, still more preferably at least 5 parts by mass, based on 100 parts by mass of the rubber component. It is 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 15 parts by mass or less. Thereby, the effect can be obtained more suitably.

The rubber composition may include silica.
Examples of the silica include dry-process silica (silicic anhydride) and wet-process silica (hydrous silicic acid), but wet-process silica is preferable because it has many silanol groups. These may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably at least 70 m ² / g, more preferably at least 150 m ² / g. When it is 70 m ² / g or more, abrasion resistance, breaking strength, and the like tend to be further improved. _N 2 SA of the silica is preferably 500 meters ² / g or less, more preferably 200m ² / g. By setting the content to 500 m ² / g or less, the processability tends to be further improved.
In addition, the nitrogen adsorption specific surface area of silica is a value measured by a BET method according to ASTM D3037-81.

As the silica, for example, products such as Degussa Co., Rhodia Co., Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd. and Tokuyama Co., Ltd. can be used.

When silica is contained, the content of silica is preferably at least 20 parts by mass, more preferably at least 30 parts by mass, and still more preferably at least 50 parts by mass, per 100 parts by mass of the rubber component. When the amount is 20 parts by mass or more, the fuel economy performance tends to be further improved. Further, the content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and further preferably 100 parts by mass or less. When the amount is 200 parts by mass or less, the balance between processability and fuel economy tends to be further improved.

The content of carbon black in the total 100% by mass of silica and carbon black is preferably at least 20% by mass, more preferably at least 50% by mass, even more preferably at least 80% by mass, and even if it is 100% by mass. Good. Thereby, the effect can be obtained more suitably.

When the rubber composition contains silica, it is preferable that the rubber composition further contains a silane coupling agent.
The silane coupling agent is not particularly limited and includes, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, Bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis ( 3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2-trimethoxysilyl) B) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, Sulfides such as triethoxysilylpropyl methacrylate monosulfide, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, NXT manufactured by Momentive, and mercapto such as NXT-Z; vinyltriethoxysilane; vinyl Vinyl-based such as trimethoxysilane, amino-based such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycid Glycidoxy type such as cypropyltrimethoxysilane, nitro type such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, and chloro type such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane And so on. These may be used alone or in combination of two or more. Among them, a sulfide-based silane coupling agent is preferable because the effect tends to be more favorably obtained.

As the silane coupling agent, for example, products such as Degussa Co., Momentive Co., Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Amax Co., Ltd., and Dow Corning Toray Co., Ltd. can be used.

When a silane coupling agent is contained, the content of the silane coupling agent is preferably at least 3 parts by mass, more preferably at least 5 parts by mass, based on 100 parts by mass of silica. When the amount is 3 parts by mass or more, the effect of addition tends to be obtained. Further, the content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less. When the amount is 20 parts by mass or less, an effect commensurate with the compounding amount is obtained, and good processability during kneading tends to be obtained.

The rubber composition may include an oil.
Examples of the oil include a process oil, a vegetable oil or a mixture thereof. As the process oil, for example, a paraffin-based process oil, an aroma-based process oil, a naphthene-based process oil, or the like can be used. Vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut water, rosin, pine oil, pine tar, tall oil, corn oil, rice oil, bean oil, sesame oil, Olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, tung oil and the like. These may be used alone or in combination of two or more. Above all, a process oil is preferable, and an aroma-based process oil is more preferable, because the effect can be obtained well.

Examples of the oil include Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., H & R Co., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu Co., Ltd., and Fuji Kosan Co., Ltd. And other products can be used.

When oil is contained, the content of the oil is preferably at least 1 part by mass, more preferably at least 5 parts by mass, and preferably at most 30 parts by mass, more preferably at most 30 parts by mass, based on 100 parts by mass of the rubber component. 20 parts by mass or less. Thereby, the effect can be obtained more suitably.

The rubber composition may include a wax.
Examples of the wax include, but are not particularly limited to, petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant waxes and animal waxes; and synthetic waxes such as polymers such as ethylene and propylene. These may be used alone or in combination of two or more. Among them, petroleum wax is preferred, and paraffin wax is more preferred.

As the wax, for example, products of Ouchi Shinko Chemical Co., Ltd., Nippon Seiro Co., Ltd., Seiko Chemical Co., Ltd., etc. can be used.

When a wax is contained, the content of the wax is preferably at least 0.3 part by mass, more preferably at least 0.5 part by mass, based on 100 parts by mass of the rubber component, from the viewpoint of the performance balance. , Preferably 20 parts by mass or less, more preferably 10 parts by mass or less. Thereby, the effect can be obtained more suitably.

The rubber composition may include an antioxidant.
Examples of the antioxidant include naphthylamine antioxidants such as phenyl-α-naphthylamine; diphenylamine antioxidants such as octylated diphenylamine and 4,4′-bis (α, α′-dimethylbenzyl) diphenylamine; -Isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, N, N'-di-2-naphthyl-p-phenylenediamine and the like A p-phenylenediamine antioxidant; a quinoline antioxidant such as a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline; 2,6-di-t-butyl-4-methylphenol; Monophenolic antioxidants such as styrenated phenol; tetrakis- [methylene-3- (3 ', 5'-di-t-butyl- '- hydroxyphenyl) propionate] bis methane, tris, and the like polyphenolic antioxidants. These may be used alone or in combination of two or more. Among them, a p-phenylenediamine antioxidant and a quinoline antioxidant are preferable.

As the anti-aging agent, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis, etc. can be used.

When the anti-aging agent is contained, the content of the anti-aging agent is preferably at least 0.5 part by mass, more preferably at least 1 part by mass, and preferably at least 10 parts by mass, based on 100 parts by mass of the rubber component. Parts by weight or less, more preferably 5 parts by weight or less. Thereby, the effect can be obtained more suitably.

The rubber composition may contain stearic acid.
Conventionally known stearic acid can be used, and for example, products such as NOF Corporation, NOF, Kao Corporation, Fuji Film Wako Pure Chemical Industries, Ltd., and Chiba Fatty Acid Corporation can be used. .

When stearic acid is contained, the content of stearic acid is preferably at least 0.5 part by mass, more preferably at least 1 part by mass, and preferably at most 10 parts by mass, based on 100 parts by mass of the rubber component. , More preferably 5 parts by mass or less. Thereby, the effect can be obtained more suitably.

The rubber composition may contain zinc oxide.
As the zinc oxide, conventionally known ones can be used. For example, products such as Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusuiteku Co., Ltd., Shodo Chemical Co., Ltd., Sakai Chemical Co., Ltd., etc. Can be used.

When zinc oxide is contained, the content of zinc oxide is preferably at least 0.5 part by mass, more preferably at least 1 part by mass, and preferably at most 10 parts by mass, based on 100 parts by mass of the rubber component. , More preferably 5 parts by mass or less. Thereby, the effect can be obtained more suitably.

The rubber composition may contain sulfur.
Examples of the sulfur include powdery sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur commonly used in the rubber industry. These may be used alone or in combination of two or more.

As the sulfur, for example, products such as Tsurumi Chemical Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Co., Ltd., Flexis, Nippon Kishii Kogyo Co., Ltd. and Hosoi Chemical Co., Ltd. can be used.

When sulfur is contained, the sulfur content is preferably at least 0.1 part by mass, more preferably at least 0.5 part by mass, and preferably at most 10 parts by mass, based on 100 parts by mass of the rubber component. , More preferably 5 parts by mass or less, even more preferably 3 parts by mass or less. Thereby, the effect can be obtained more suitably.

The rubber composition may contain a vulcanization accelerator.
Examples of the vulcanization accelerator include thiazole vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; tetramethylthiuram disulfide (TMTD ), Tetrabenzylthiuram disulfide (TBzTD), thiuram-based vulcanization accelerators such as tetrakis (2-ethylhexyl) thiuram disulfide (TOT-N); N-cyclohexyl-2-benzothiazolesulfenamide, Nt-butyl- 2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide and the like The Sulfena De-based vulcanization accelerator; diphenylguanidine, may be mentioned di-ortho-tolyl guanidine, guanidine-based vulcanization accelerators such as ortho tri ruby guanidine. These may be used alone or in combination of two or more. Among them, a sulfenamide-based vulcanization accelerator and a guanidine-based vulcanization accelerator are preferable because the effect can be more suitably obtained.

As the vulcanization accelerator, for example, products manufactured by Kawaguchi Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Sanshin Chemical Industry Co., Ltd. can be used.

When a vulcanization accelerator is contained, the content of the vulcanization accelerator is preferably at least 1 part by mass, more preferably at least 2 parts by mass, and preferably at least 10 parts by mass, per 100 parts by mass of the rubber component. Parts by weight, more preferably 7 parts by weight or less, still more preferably 5 parts by weight or less. Thereby, the effect can be obtained more suitably.

In the rubber composition, in addition to the above components, additives generally used in the tire industry, for example, organic peroxides; fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica And the like may be further blended. The content of these additives is preferably 0.1 to 200 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition can be produced, for example, by a method of kneading the above components using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanizing.

As the kneading conditions, in the base kneading step of kneading additives other than the vulcanizing agent and the vulcanization accelerator, the kneading temperature is usually 100 to 180 ° C, preferably 120 to 170 ° C. In the final kneading step of kneading the vulcanizing agent and the vulcanization accelerator, the kneading temperature is usually 120 ° C or lower, preferably 80 to 110 ° C. The composition obtained by kneading a vulcanizing agent and a vulcanization accelerator is usually subjected to vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 140 to 190C, preferably 150 to 185C. The vulcanization time is usually 5 to 15 minutes.

The rubber composition includes, for example, a tread (cap tread), a sidewall, a base tread, an undertread, a clinch, a bead apex, a breaker cushion rubber, a rubber for covering a carcass cord, an insulation, a chafer, an inner liner, and the like, It can be used for a tire member such as a side reinforcing layer of a run flat tire (as a rubber composition for a tire). Especially, it is used suitably for a tread. Further, the rubber composition can be used for shoe sole rubber, vibration-isolating rubber, belts, hoses, and other industrial rubber products.

The pneumatic tire of the present invention is manufactured by a usual method using the above rubber composition. That is, the rubber composition containing various additives as necessary is extruded at the unvulcanized stage in accordance with the shape of each member of the tire (especially, the tread (cap tread)), and is put on a tire molding machine. After forming the unvulcanized tire by forming in an ordinary method and bonding together with other tire members to form an unvulcanized tire, the tire can be manufactured by heating and pressing in a vulcanizer.

In addition, the tire member (for example, tread) of the pneumatic tire only needs to be at least partially formed of the rubber composition, and may be entirely formed of the rubber composition.

The above pneumatic tires include passenger car tires, large passenger car tires, large SUV tires, truck / bus tires, motorcycle tires, competition tires, studless tires (winter tires), run flat tires, aircraft tires, and mine tires. It is suitably used as a tire for vehicles.

The present invention will be specifically described based on examples, but the present invention is not limited to these.

Various chemicals used in Examples and Comparative Examples will be described together.
NR: TSR20
SBR: Nipol 1502 manufactured by Zeon Corporation
BR: BR150B manufactured by Ube Industries, Ltd. (cis content: 98% by mass)
CB1-6: Carbon black having the properties shown in Table 1 below (prototype)
Silica: VN3 (N ₂ SA: 175 m ² / g) manufactured by Evonik Degussa
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Evonik Degussa
Oil: Diana Process NH-70S (aroma-based process oil) manufactured by Idemitsu Kosan Co., Ltd.
Zinc oxide: 3 types of zinc oxide manufactured by Hakusui Tech Co., Ltd. Stearic acid: Beaded stearic acid "Tsubaki" manufactured by NOF Corporation
Sulfur: powdered sulfur from Tsurumi Chemical Co., Ltd. (containing 5% oil)
Vulcanization accelerator: Noxeller NS (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

(Examples and Comparative Examples)
According to the composition shown in Tables 2 and 3, materials other than sulfur and the vulcanization accelerator were kneaded for 5 minutes at 150 ° C. using a Banbury mixer manufactured by Kobe Steel Ltd. to obtain a kneaded product. Was. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded material, and the mixture was kneaded with an open roll at 80 ° C. for 5 minutes to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition is formed into a tread shape, bonded together with other tire members to form an unvulcanized tire, and press-vulcanized at 170 ° C. for 10 minutes to obtain a test tire ( Size: 195 / 65R15).
The unvulcanized rubber composition was press-vulcanized at 170 ° C. for 10 minutes to obtain a vulcanized rubber composition.
The following evaluation was performed using the obtained unvulcanized rubber composition, vulcanized rubber composition, and test tire.

(Workability)
For each unvulcanized rubber composition, according to the method of measuring Mooney viscosity according to JIS K 6300-1, "Unvulcanized rubber-physical properties-Part 1: Determination of viscosity and scorch time using Mooney viscometer" The Mooney viscosity (ML1 + 4) was measured at a temperature of 130 ° C. The results were indexed for each table with the Mooney viscosity of Comparative Example 1-1 and Comparative Example 2-1 being 100 (processability index). The larger the index, the lower the Mooney viscosity and the better the processability. It was judged to be good when it was 95 or more.

(Wear resistance)
Each test tire was mounted on a domestic FF vehicle, the groove depth of the tire tread portion after a running distance of 8000 km was measured, and the running distance when the tire groove depth was reduced by 1 mm was calculated. The results are shown in each table as an index when the running distance of Comparative Example 1-1 and Comparative Example 2-1 is set to 100 (wear resistance index). The larger the index, the longer the running distance when the tire groove depth is reduced by 1 mm and the more excellent the wear resistance.
It was judged to be good when it was 95 or more.

(Low fuel consumption)
Using a rolling resistance tester, the rolling resistance was measured when the test tire was run under the conditions of a rim (15 × 6JJ), an internal pressure (230 kPa), a load (3.43 kN), and a speed (80 km / h). did. Then, in each table, the rolling resistance of Comparative Example 1-1 and Comparative Example 2-1 was set to 100 and indexed (low fuel consumption index). The larger the index, the smaller the rolling resistance and the better the fuel economy.
It was judged to be good when it was 95 or more.

(Breaking strength)
According to JIS K6251 “How to determine tensile properties of vulcanized rubber and thermoplastic rubber”, a tensile test was performed using a No. 3 dumbbell, and the breaking strength (TB) of the vulcanized rubber composition was measured. In addition, in each table, EB of Comparative Example 1-1 and Comparative Example 2-1 was set to 100, and TB of each compound was indicated by an index (rupture strength index). The larger the index, the better the breaking strength.
It was judged to be good when it was 95 or more.

As shown in Tables 2 and 3, in the examples including the specific carbon black, good workability, abrasion resistance, low fuel consumption, and breaking strength (particularly, abrasion resistance and breaking strength) were obtained.

Claims (6)

A rubber composition containing 2 to 200 parts by mass of carbon black having a hydrogen release rate of 0.20% by mass or more and a nitrogen adsorption specific surface area of 160 to 190 m ² / g based on 100 parts by mass of a rubber component. The carbon black has an oil absorption amount of compression is 90~150cm ³ / 100g claim 1 rubber composition. The rubber composition according to claim 1, wherein the carbon black has a maximum frequency Stokes equivalent diameter of 50 to 100 nm. The rubber composition according to any one of claims 1 to 3, wherein the carbon black has a Stokes equivalent diameter half width of 30 to 90 nm. The rubber composition according to any one of claims 1 to 4, which is a rubber composition for a tire. A pneumatic tire having a tread produced using the rubber composition according to claim 1.