Rubber composition and composite

Abstract

To provide a rubber composition, a composite and a tire with which control stability during high-speed driving can be improved.SOLUTION: In the rubber composition, the Mooney viscosity V and the complex elastic modulus E* [MPa] satisfy the formula (1) defined by V / E*≤3.0. (In the formula, V represents the Mooney viscosity ML1+4 at the temperature of 130°C, and E* represents the complex elastic modulus under conditions where the temperature is 30°C, the initial strain is 5%, the dynamic strain is ±1%, and the frequency is 10 Hz.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a rubber composition, a composite, and a tire using the same. [Background technology]

[0002] Techniques have been proposed for compounding fillers such as carbon black and silica into rubber compositions to reinforce the rubber composition and improve its modulus (complex elastic modulus). For example, various techniques for dispersing fillers have been disclosed, such as a method for producing a silica-natural rubber composite from a compounded latex obtained by mixing natural rubber latex with a dispersion of fine silica particles with an average particle size of 1 μm or less in the presence of a nonionic or cationic surfactant (see Patent Document 1, for example). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-107211 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in recent years, as long-distance driving on expressways has become common, further improvements in handling stability during high-speed driving are desired. An object of the present invention is to provide a rubber composition, a composite, and a tire that can solve the above problems and improve the steering stability during high-speed driving. [Means for solving the problem]

[0005] The present invention uses Mooney viscosity V and complex modulus E * The rubber composition satisfies the following formula (1): (1)V / E * <=3.0 (Wherein, V is the Mooney viscosity ML at a temperature of 130°C. 1+4 Represents E *represents the complex modulus of elasticity under the conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of ±1%, and a frequency of 10 Hz.

[0006] The rubber composition has a nitrogen adsorption specific surface area of ​​190 m 2 It is preferable that the silica content is at least 1 / g.

[0007] The rubber composition preferably contains a nonionic surfactant and an anionic surfactant.

[0008] The rubber composition preferably contains a complex obtained by mixing an isoprene-based rubber, silica, a nonionic surfactant, and an anionic surfactant.

[0009] The rubber composition has the Mooney viscosity V and the complex modulus E * It is preferable that [MPa] satisfies the following formula. V / E * <= 2.2

[0010] 6. The rubber composition according to claim 1, wherein the Mooney viscosity V satisfies the following formula: V≦40.0

[0011] The complex elastic modulus E * It is preferable that [MPa] satisfies the following formula. E * ≧8.0MPa

[0012] The rubber composition preferably contains at least one selected from the group consisting of an ether-type nonionic surfactant, an ester-type nonionic surfactant, and an ether-ester-type nonionic surfactant.

[0013] The rubber composition preferably contains at least one selected from the group consisting of carboxylic acid-based anionic surfactants, sulfonic acid-based anionic surfactants, sulfate ester-based anionic surfactants, and phosphate ester-based anionic surfactants.

[0014] The present invention relates to a composite obtained by a production method including the steps of mixing a surfactant and a filler dispersion to prepare a mixed liquid, and mixing the prepared mixed liquid with rubber latex, wherein the surfactant includes a nonionic surfactant and an anionic surfactant, the filler includes silica, and the rubber latex includes an isoprene-based rubber.

[0015] The composite has a nitrogen adsorption specific surface area of ​​190 m 2 It is preferable that the silica content is at least 1 / g.

[0016] The present invention also relates to a tire using the rubber composition or the composite. Effect of the Invention

[0017] According to the present invention, the Mooney viscosity V and the complex modulus E * Since the rubber composition satisfies the above formula (1) [MPa], the steering stability during high speed driving can be improved. (1)V / E * <=3.0 (Wherein, V is the Mooney viscosity ML at a temperature of 130°C. 1+4 Represents E * represents the complex modulus of elasticity under the conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of ±1%, and a frequency of 10 Hz. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention uses Mooney viscosity V and complex modulus E * The rubber composition satisfies the above formula (1). The rubber composition can provide good steering stability during high-speed driving.

[0019] The reason why the above-mentioned effects are obtained is not entirely clear, but it is presumed that they are due to the following mechanism. In order to improve the driving stability, it is necessary to increase the rigidity of the rubber composition, but if there is variation in the gauge around the tire, there will be a difference in the stress generated between the thick and thin parts. Therefore, during high-speed driving where the rubber composition frequently comes into contact with the road surface repeatedly, the effect of this difference becomes significant, and it is considered that the driving stability during high-speed driving cannot be improved by simply improving the rigidity. The present invention is a rubber composition having a complex modulus E under conditions of initial strain of 5%, dynamic strain of ±1%, and frequency of 10 Hz while lowering the Mooney viscosity at 130°C. * By increasing the axial length of the tire and satisfying the formula (1), it is possible to make the rubber flow (gauge) uniform around the tire during vulcanization while increasing the rigidity of the rubber. Therefore, during high-speed driving where the rubber frequently comes into contact with the road surface, the rubber gauge becomes uniform around the tire, and the stress around the tire becomes uniform and high, providing high steering stability. Therefore, it is presumed that by satisfying the formula (1), steering stability during high-speed driving is significantly improved.

[0020] Thus, Mooney viscosity V and complex modulus E * By configuring the rubber composition so that the V / E ratio satisfies the above formula (1), the problem (objective) of improving the steering stability during high-speed driving is solved. * The parameter "≦3.0" does not define the problem (objective); the problem of this application is to improve the handling stability during high-speed driving, and the configuration that satisfies this parameter is used as a means to achieve this.

[0021] The rubber composition has a Mooney viscosity V (Mooney viscosity V of the unvulcanized rubber composition) and a complex modulus E * [MPa] (Complex modulus of elasticity E of rubber composition after vulcanization) * ) satisfies the following formula (1). (1)V / E * <=3.0 (Wherein, V is the Mooney viscosity ML at a temperature of 130°C. 1+4 Represents E * represents the complex modulus of elasticity under the conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of ±1%, and a frequency of 10 Hz.

[0022] V / E * From the viewpoint of steering stability during high-speed driving, V / E is preferably 2.7 or less, more preferably 2.4 or less, even more preferably 2.2 or less, particularly preferably 2.0 or less, and most preferably 1.8 or less. * The lower limit of is not particularly limited, but is preferably 0.3 or more, more preferably 0.5 or more, even more preferably 0.7 or more, and particularly preferably 0.9 or more.

[0023] From the viewpoint of steering stability during high-speed driving, it is preferable that the Mooney viscosity V of the rubber composition (Mooney viscosity V of an unvulcanized rubber composition) satisfies the following formula: V≦40.0 V is preferably 35.0 or less, more preferably 30.0 or less, even more preferably 28.0 or less, particularly preferably 26.0 or less, and most preferably 24.0 or less. There is no particular restriction on the lower limit of V, but it is preferably 10.0 or more, more preferably 15.0 or more, even more preferably 18.0 or more, and particularly preferably 20.0 or more.

[0024] From the viewpoint of steering stability during high-speed driving, the rubber composition has a complex modulus of elasticity E * [MPa] (Complex modulus of elasticity E of rubber composition after vulcanization) * ) preferably satisfies the following formula: E * ≧8.0MPa E * is preferably 9.0 MPa or more, more preferably 10.0 MPa or more, even more preferably 10.5 MPa or more, particularly preferably 11.0 MPa or more, and most preferably 12.0 MPa or more. * The upper limit is not particularly limited, but is preferably 20.0 MPa or less, more preferably 18.0 MPa or less, and even more preferably 16.0 MPa or less.

[0025] Mooney viscosity V(ML) of rubber composition (unvulcanized rubber composition) 1+4(130°C)) can be adjusted by the types and amounts of chemicals (especially rubber components, fillers, softeners, sulfur, vulcanization accelerators, silane coupling agents, and surfactants) added to the rubber composition. For example, the use of surfactants, the use of low Mooney viscosity rubber, and the reduction in the amount of filler tend to reduce V.

[0026] Complex modulus E of rubber composition (rubber composition after vulcanization) * can be adjusted by the type and amount of chemicals (especially rubber components, fillers, softeners, sulfur, vulcanization accelerators, and silane coupling agents) compounded in the rubber composition. For example, by reducing the amount of softener, increasing the amount of filler, increasing the amount of sulfur, or increasing the amount of vulcanization accelerator, E * tends to be large.

[0027] V / E of rubber composition * The V / E ratio can be adjusted by the type and amount of chemicals (especially rubber components, fillers, softeners, sulfur, vulcanization accelerators, silane coupling agents, and surfactants) that are mixed into the rubber composition. For example, the V / E ratio can be adjusted by using surfactants (especially nonionic surfactants and anionic surfactants), using rubber with a low Mooney viscosity, using silica with a large nitrogen adsorption specific surface area, or by combining it with a surfactant. * tends to be smaller.

[0028] The Mooney viscosity V is the Mooney viscosity ML of the unvulcanized rubber composition. 1+4 (130℃), complex modulus of elasticity E * is the complex modulus of the rubber composition after vulcanization (under conditions of temperature 30° C., initial strain 5%, dynamic strain ±1%, and frequency 10 Hz), and specifically, can be measured by the method described in the Examples below.

[0029] (Rubber component) As the rubber component usable in the rubber composition, for example, diene rubber can be used. Examples of diene rubber include isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). Examples of butyl rubber and fluororubber are also included. These may be used alone or in combination of two or more. Among them, from the viewpoint of steering stability during high-speed driving, isoprene rubber, BR, and SBR are preferred, and isoprene rubber is more preferred.

[0030] The diene rubber may be a non-modified diene rubber or a modified diene rubber. The modified diene rubber may be any diene rubber having a functional group that interacts with a filler such as silica. Examples of the modified diene rubber include terminal-modified diene rubber (terminal-modified diene rubber having the functional group at the terminal) in which at least one terminal of the diene rubber has been modified with a compound (modifier) ​​having the functional group, main-chain modified diene rubber having the functional group in the main chain, main-chain terminal-modified diene rubber having the functional group in the main chain and at least one terminal (for example, main-chain terminal-modified diene rubber having the functional group in the main chain and at least one terminal modified with the modifier), and terminal-modified diene rubber modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or epoxy group introduced therein.

[0031] Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, and an epoxy group. These functional groups may have a substituent. Among them, an amino group (preferably an amino group in which a hydrogen atom of an amino group is substituted with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), and an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

[0032] Examples of isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. Examples of NR include SIR20, RSS♯3, TSR20, and other rubber industry-standard rubbers. Examples of IR include IR2200 and other rubber industry-standard rubbers. Examples of modified NR include deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), and other rubbers. Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0033] In the rubber composition, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 50% by mass or more, further preferably 75% by mass or more, particularly preferably 85% by mass or more, and may be 100% by mass. By keeping it within the above range, the handling stability during high-speed driving tends to be improved.

[0034] The BR is not particularly limited, and for example, high cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, BR synthesized using a rare earth catalyst (rare earth BR), etc. can be used. These may be used alone or in combination of two or more. In particular, the BR preferably contains high cis BR with a cis content of 90% by mass or more. The cis content is more preferably 95% by mass or more. The cis content can be measured by infrared absorption spectroscopy.

[0035] In addition, either unmodified or modified BR can be used as the BR. Modified BR includes modified BR into which functional groups similar to those of modified diene rubbers have been introduced. In addition, hydrogenated butadiene polymer (hydrogenated BR) can also be used as the BR.

[0036] As the BR, for example, products from Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Zeon Corporation, etc. can be used.

[0037] When the rubber composition contains BR, 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 even more preferably 15% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. By keeping the content within the above range, the handling stability during high-speed driving tends to be improved.

[0038] The SBR is not particularly limited, and for example, emulsion polymerized styrene butadiene rubber (E-SBR), solution polymerized styrene butadiene rubber (S-SBR), etc. can be used. These may be used alone or in combination of two or more kinds.

[0039] The styrene content of the SBR is preferably 5% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more. The styrene content is preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. By keeping the styrene content within the above range, the handling stability during high-speed driving tends to be improved. In this specification, the styrene content is 1 It can be measured by H-NMR measurement.

[0040] The vinyl bond content of SBR is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. The vinyl bond content is preferably 25% by mass or less, more preferably 15% by mass or less, and even more preferably 13% by mass or less. By keeping it within the above range, the handling stability during high-speed driving tends to be improved. In this specification, the vinyl bond amount (1,2-bonded butadiene unit amount) can be measured by infrared absorption spectroscopy.

[0041] Both unmodified and modified SBR can be used. Modified SBR includes modified SBR with the same functional groups as modified diene rubber. Hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used as SBR.

[0042] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd., and the like can be used.

[0043] When the rubber composition contains SBR, the content of SBR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. By keeping the content within the above range, the handling stability during high-speed driving tends to be improved.

[0044] (Filler) From the viewpoint of steering stability during high-speed driving, the rubber composition desirably contains a filler.

[0045] The filler (filling material) is not particularly limited, and materials known in the rubber field can be used, for example, inorganic fillers such as silica, carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, mica, etc.; poorly dispersible fillers, etc. Among them, from the viewpoint of steering stability during high-speed driving, silica; carbon-derived fillers (carbon-containing fillers) such as carbon black are preferred, and silica is more preferred.

[0046] In the rubber composition, the content of the filler (total amount of the filler) is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit of the content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 130 parts by mass or less, and particularly preferably 120 parts by mass or less. By keeping the content within the above range, the steering stability during high-speed driving tends to be improved.

[0047] Usable silica includes dry process silica (anhydrous silica) and wet process silica (hydrated silica). Among them, wet process silica is preferred because it has a large number of silanol groups. Commercially available products include those from Degussa, Rhodia, Tosoh Silica, Solvay Japan, and Tokuyama. These may be used alone or in combination of two or more.

[0048] The nitrogen adsorption specific surface area of ​​silica (N 2 SA) is preferably 50m 2 / g or more, more preferably 100m 2 / g or more, more preferably 150m 2 / g or more, particularly preferably 180m 2 / g or more, most preferably 190m 2 / g or more. In addition, the N content of silica 2 The upper limit of SA is not particularly limited, but is preferably 350 m 2 / g or less, more preferably 300m 2 / g or less, more preferably 250m 2By keeping the ratio within the above range, the steering stability during high speed driving tends to be improved. 2 SA190m 2 By using finely divided silica having a particle size of 100 nm or more, sufficient reinforcing properties can be obtained, making it easier to satisfy the specific parameters of the present invention, and also tends to have a large effect of improving steering stability during high-speed driving. In addition, the N of silica 2 SA is a value measured by the BET method in accordance with ASTM D3037-93.

[0049] In the rubber composition, the content of silica is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and particularly preferably 50 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit of the content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 130 parts by mass or less, and particularly preferably 120 parts by mass or less. By keeping the content within the above range, the steering stability during high-speed driving tends to be improved.

[0050] 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 those known in the rubber field can be used. 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-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N, Examples of such silylsilanes include sulfide-based silylsilanes such as N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based silylsilanes such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z; vinyl-based silylsilanes such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based silylsilanes such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based silylsilanes such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silylsilanes such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based silylsilanes such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products include those manufactured by Degussa, Momentive, Shin-Etsu Silicones, Tokyo Chemical Industry, Azumax, and Dow Corning Toray Co., Ltd. These may be used alone or in combination of two or more.

[0051] In the rubber composition, the content of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more, based on 100 parts by mass of silica. The upper limit of the content is preferably 50 parts by mass, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. By keeping it within the above range, the steering stability during high-speed driving tends to be improved.

[0052] Carbon black that can be used in the rubber composition is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Co., Ltd., Shinnikka Carbon Co., Ltd., Columbia Carbon Co., Ltd., and the like. These may be used alone or in combination of two or more kinds.

[0053] The nitrogen adsorption specific surface area of ​​carbon black (N 2 SA) is 30m 2 / g or more is preferable, and 50m 2 / g or more is more preferable, and 70m 2 / g or more is more preferable. 2 SA is 200m 2 / g or less is preferable, and 150m 2 / g or less is more preferable, and 130m 2 / g or less is more preferable, and 120m 2 By keeping it within the above range, there is a tendency that the handling stability during high speed driving is improved.

[0054] In the rubber composition, the content of carbon black is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less. By keeping the content within the above range, the steering stability during high-speed driving tends to be improved.

[0055] Examples of the poorly dispersible filler include microfibrillated vegetable fibers, short fiber cellulose, gel compounds, etc. Among these, microfibrillated vegetable fibers are preferred.

[0056] The microfibrillated plant fiber is preferably cellulose microfibril, since it has good reinforcing properties. The cellulose microfibril is not particularly limited as long as it is derived from a natural product, and examples thereof include those derived from resource biomass such as fruits, grains, and root vegetables, wood, bamboo, hemp, jute, and kenaf, and pulp, paper, cloth, agricultural waste, waste biomass such as food waste and sewage sludge obtained from these as raw materials, unused biomass such as rice straw, wheat straw, and thinned wood, as well as cellulose produced by sea squirts, acetic acid bacteria, etc. These microfibrillated plant fibers may be used alone or in combination of two or more.

[0057] In this specification, cellulose microfibrils typically refer to cellulose fibers having an average fiber diameter of 10 μm or less, more typically cellulose fibers having a microstructure formed by the aggregation of cellulose molecules and an average fiber diameter of 500 nm or less. Typical cellulose microfibrils are formed, for example, as an aggregate of cellulose fibers having the above-mentioned average fiber diameter.

[0058] In the rubber composition, the content of the poorly dispersible filler is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less. By keeping the content within the above range, the steering stability during high-speed driving tends to be improved.

[0059] (Surfactant) From the viewpoint of steering stability during high-speed driving, the rubber composition desirably contains a surfactant.

[0060] The surfactant is a compound having a hydrophobic group and a hydrophilic group, and examples thereof include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. The surfactant may be used alone or in combination of two or more, but it is preferable to use two or more. Among them, from the viewpoint of steering stability during high-speed driving, nonionic surfactants and anionic surfactants are preferred, and it is more preferable to use nonionic surfactants and anionic surfactants in combination.

[0061] The reason why the above-mentioned effects are obtained is not entirely clear, but it is presumed that they are due to the following mechanism. For example, when silica is used as a filler, the silica aggregates are first loosened by a nonionic surfactant, and the SiOH groups on the surface of the loosened silica are then removed. + and COO of anionic surfactants -Strong adsorption occurs due to hydrogen bonding with anionic groups such as , making it possible to stably disperse silica in silica dispersions, etc. Next, when such a dispersion with stabilized silica is mixed with rubber components such as rubber latex, an interaction occurs between the hydrophobic groups of the anionic surfactant and the rubber, and the silica is adsorbed around the rubber particles via the surfactant. Then, by further mixing the mixture of rubber, silica, etc., which has been prepared, with a roll or the like, the loosely aggregated silica is dispersed, and a silica-rubber composite (master batch) in which the silica is dispersed throughout the rubber is obtained. Therefore, it is presumed that the use of such a composite in a rubber composition will provide excellent steering stability at high speeds.

[0062] The nonionic surfactant is not particularly limited, and known surfactants can be used. For example, ether-type nonionic surfactants, ester-type nonionic surfactants, and ether ester-type nonionic surfactants can be suitably used.

[0063] The ether-type nonionic surfactant is not particularly limited, and conventionally known surfactants can be used, such as polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ethers, polyoxyethylene polypropylene alkyl ethers, and polyoxyethylene polybutylene alkyl ethers; polyoxyalkylene alkenyl ethers such as polyoxyethylene alkenyl ethers; polyoxyethylene alkyl phenyl ethers; and higher fatty acid alkanolamides.

[0064] Specific examples of suitable ether-type nonionic surfactants include polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether, and polyoxyethylene 2-octyldodecyl ether.

[0065] As the ether-type nonionic surfactant, the compounds represented by the following formulae (I-1) to (I-3) can be preferably used. Among them, the compound represented by the following formula (I-1) is particularly preferably used.

[0066] R 11 -O-(EO) x1 -H (I-1) (In the formula, R 11 represents an alkyl group having 3 to 50 carbon atoms or an alkenyl group having 3 to 50 carbon atoms. EO represents an oxyethylene group. The average number of moles added x1 is 3 to 100.

[0067] R 11 The number of carbon atoms is preferably 5 to 30, and more preferably 8 to 20. The above x1 is preferably 5 to 50, and more preferably 8 to 30.

[0068] R 12 -O-(AO) y1 (EO) z1 -H (I-2) (In the formula, R 12 represents an alkyl group having 3 to 50 carbon atoms or an alkenyl group having 3 to 50 carbon atoms. AO represents an oxypropylene group or an oxybutylene group, and EO represents an oxyethylene group. The average number of moles added y1 is 3 to 100, and the average number of moles added z1 is 3 to 100.

[0069] R 12 The number of carbon atoms is preferably 5 to 30, more preferably 8 to 20. The above y1 is preferably 5 to 50, more preferably 8 to 30. The above z1 is preferably 5 to 50, more preferably 8 to 30. The arrangement of EO and AO may be block or random.

[0070] [ka]

[0071] In the above formula (I-3), R 13 ~R 15are the same or different and represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 1 to 30 carbon atoms, or an alkoxy group having 1 to 30 carbon atoms. 16 represents an alkylene group having 1 to 30 carbon atoms. EO represents an oxyethylene group. The average number of moles added a is 0 to 50, the average number of moles added b is 0 to 50, and the average number of moles added c is 1 to 50.

[0072] R 13 and R 14 The number of carbon atoms in R is preferably 1 to 25. 15 is preferably a hydrogen atom or an alkyl group having 1 to 25 carbon atoms. 16 The number of carbon atoms is preferably 3 to 8. The above a and b are preferably 0 to 30, more preferably 5 to 30, and the above c is preferably 1 to 30, more preferably 1 to 10.

[0073] The ester-type nonionic surfactant is not particularly limited, and examples thereof include alkylene oxide adducts of fatty acids, alkylene oxide adducts of polyhydric alcohol fatty acid esters, fatty acid adducts of polyhydric alcohols (esterification products), etc. Among these, alkylene oxide adducts of fatty acids are preferred.

[0074] The fatty acids constituting these ester-type nonionic surfactants are preferably fatty acids having 10 or more carbon atoms, more preferably 12 or more carbon atoms. There is no particular upper limit, but the number of carbon atoms is preferably 30 or less, more preferably 24 or less. Specific examples of fatty acids include saturated fatty acids such as capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, henicosylic acid, behenic acid, tricosylic acid, and lignoceric acid; and unsaturated fatty acids such as α-linolenic acid, stearidonic acid, eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid, linoleic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, docosapentaenoic acid, palmitoleic acid, vaccenic acid, paulic acid, oleic acid, elaidic acid, erucic acid, and nervonic acid.

[0075] Examples of the alkylene oxide constituting these ester-type nonionic surfactants include ethylene oxide, propylene oxide, butylene oxide, etc. Among these, ethylene oxide and propylene oxide are preferred, and ethylene oxide is more preferred.

[0076] The polyhydric alcohols that make up these ester-type nonionic surfactants include CH 2 OH-(CHOH) n -CH 2 OH (n is an integer of 1 to 20). The compound represented by this formula may be cyclized by dehydration. Specific examples of the compound represented by this formula include glycerin, sorbit, and sorbitan. In addition, the polyhydric alcohol may be polyglycerin.

[0077] Specific examples of suitable ester-type nonionic surfactants include fatty acid ethylene oxide adducts such as polyethylene glycol monolaurate and polyethylene glycol monooleate; fatty acid esters of glycerol such as glycerol monostearate; fatty acid esters of pentaerythritol such as pentaerythritol di-beef tallow fatty acid ester; fatty acid esters of sorbitol and sorbitan such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan monostearate; and fatty acid esters of sucrose.

[0078] As the ester-type nonionic surfactant, a compound represented by the following formula (II) can be suitably used.

[0079] R 21 -C(O)-O-(EO) x2 -H (II) (In the formula, R 21 represents an alkyl group having 3 to 50 carbon atoms or an alkenyl group having 3 to 50 carbon atoms. EO represents an oxyethylene group. The average number of moles added x2 is 3 to 100.

[0080] R21 The number of carbon atoms is preferably 5 to 30, and more preferably 8 to 20. The above x2 is preferably 5 to 50, and more preferably 8 to 30.

[0081] Examples of the ether ester type nonionic surfactant include compounds in which a polyalkyleneoxy group (preferably an ethyleneoxy group, a propyleneoxy group or a butyleneoxy group, more preferably an ethyleneoxy group or a propyleneoxy group, and even more preferably an ethyleneoxy group) is added to a portion of the hydroxyl groups to which no fatty acid is added in the fatty acid adduct of the polyhydric alcohol.Specific examples include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tetraoleate, and polyoxyethylene sorbitol tetraoleate.Further examples include polyoxyethylene castor oil and polyoxyethylene hydrogenated castor oil.

[0082] The HLB value of the nonionic surfactant (calculated by the Griffin method) is preferably 8.0 or more, more preferably 10.0 or more, even more preferably 11.0 or more, and particularly preferably 11.5 or more. The HLB value is preferably 19.0 or less, more preferably 17.0 or less, even more preferably 15.0 or less, and particularly preferably 14.0 or less. By keeping it within the above range, the steering stability during high-speed driving tends to be improved.

[0083] As commercially available nonionic surfactants, for example, products from Elementis, Kao Corporation, Daiichi Kogyo Seiyaku Co., Ltd., Sanyo Chemical Industries, Ltd., etc. can be used.

[0084] The anionic surfactant is not particularly limited, and any known surfactant having a hydrophobic group and a hydrophilic group can be used.

[0085] The hydrophobic group may be any hydrophobic functional group, and is preferably a hydrocarbon group. The hydrocarbon group may be linear, branched, or cyclic, and includes an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Among them, an aliphatic hydrocarbon group and an aromatic hydrocarbon group are preferred. The carbon number of the hydrocarbon group is preferably 4 to 20, more preferably 4 to 15, and even more preferably 4 to 12.

[0086] The aliphatic hydrocarbon group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms. Preferred examples include alkyl groups having the above carbon numbers, specifically, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and octadecyl groups. In addition, alkenyl groups and alkynyl groups having the above carbon numbers are also included, and examples thereof include alkenyl groups such as vinyl, allyl, 1-propenyl, 1-methylethenyl, and isobutylene groups, and alkynyl groups such as ethynyl and propargyl groups. Among them, isobutylene groups are preferred. The above aliphatic hydrocarbon group may be a group further having a substituent in addition to the exemplified aliphatic hydrocarbon groups.

[0087] The alicyclic hydrocarbon group preferably has 3 to 8 carbon atoms, and specific examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a cyclooctenyl group, etc. The alicyclic hydrocarbon group may be a group further having a substituent in addition to the exemplified alicyclic hydrocarbon groups.

[0088] The aromatic hydrocarbon group preferably has 6 to 12 carbon atoms, and specific examples thereof include a phenyl group, a benzyl group, a phenethyl group, a tolyl group, a xylyl group, and a naphthyl group. Among these, a phenyl group, a benzyl group, and a phenethyl group are preferred, a phenyl group and a benzyl group are more preferred, and a phenyl group is particularly preferred. In addition, the substitution position of the methyl group on the benzene ring in the tolyl group and the xylyl group may be any of the ortho position, the meta position, and the para position. The aromatic hydrocarbon group may be a group further having a substituent in the exemplified aromatic hydrocarbon group.

[0089] The hydrophilic group is preferably at least one selected from the group consisting of a carboxyl group, a sulfonic acid group, a sulfate group, and a phosphate group, with a carboxyl group being particularly preferred.

[0090] The anionic surfactants can be specifically classified into carboxylic acid-based, sulfonic acid-based, sulfate-based, and phosphate-based surfactants.

[0091] Examples of the carboxylic acid surfactant include fatty acid salts having 6 to 30 carbon atoms, polycarboxylic acid salts, rosin acid salts, dimer acid salts, polymer acid salts, tall oil fatty acid salts, polycarboxylic acid type polymer surfactants, etc., and preferably carboxylic acid salts having 10 to 20 carbon atoms, polycarboxylic acid salts, and polycarboxylic acid type polymer surfactants, and particularly preferably polycarboxylic acid type polymer surfactants. Examples of the sulfonic acid surfactant include alkylbenzene sulfonate, alkyl sulfonate, alkylnaphthalene sulfonate, naphthalene sulfonate, diphenyl ether sulfonate, etc. Examples of the sulfate ester surfactant include alkyl sulfate, polyoxyalkylene alkyl sulfate, polyoxyalkylene alkylphenyl ether sulfate, tristyrenated phenol sulfate, distyrenated phenol sulfate, α-olefin sulfate, alkyl succinate sulfate, polyoxyalkylene tristyrenated phenol sulfate, polyoxyalkylene distyrenated phenol sulfate, etc. Examples of the phosphate surfactant include alkyl phosphate salts and polyoxyalkylene phosphate salts. Examples of the salts of these compounds include metal salts (Na, k, Ca, Mg, Zn, etc.), ammonium salts, and amine salts (triethanolamine salts, etc.). The alkyl group in these surfactants includes an alkyl group having 4 to 30 carbon atoms. The polyoxyalkylene group includes those having an alkylene group having 2 to 4 carbon atoms, and for example, those having an added mole number of ethylene oxide of about 1 to 50 moles can be used.

[0092] The anionic surfactant preferably has a weight average molecular weight (Mw) of 500 or more, more preferably 1000 or more, and even more preferably 1500 or more. Moreover, Mw is preferably 50000 or less, more preferably 30000 or less, and even more preferably 20000 or less.

[0093] As commercially available anionic surfactants, for example, products from Elementis, Kao Corporation, Daiichi Kogyo Seiyaku Co., Ltd., Sanyo Chemical Industries, Ltd., EVONIK-DEGUSSA Co., Ltd., Huntsman Corporation, and the like can be used.

[0094] In the rubber composition, the content of the surfactant (total amount of surfactants such as nonionic surfactants and anionic surfactants) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 9 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less. By keeping it within the above range, the steering stability during high-speed driving tends to be improved. It is preferable that the content of the nonionic surfactant and the content of the anionic surfactant are also in the same range.

[0095] (Plasticizer) The rubber composition may contain a plasticizer. A plasticizer is a material that imparts plasticity to a rubber component, and examples of the plasticizer include liquid plasticizers (plasticizers that are in a liquid state at room temperature (25° C.)) and resins (resins that are in a solid state at room temperature (25° C.)).

[0096] In the rubber composition, the content of the plasticizer (total amount of plasticizer) is, from the viewpoint of handling stability during high-speed driving, preferably 100 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and may be 0 parts by mass, per 100 parts by mass of the rubber component.

[0097] Liquid plasticizers (plasticizers that are in a liquid state at room temperature (25° C.)) that can be used in the rubber composition are not particularly limited, and examples thereof include oils, liquid polymers (liquid resins, liquid diene-based polymers, etc.), etc. These may be used alone or in combination of two or more kinds.

[0098] In the rubber composition, the content of the liquid plasticizer is preferably 100 parts by mass or less, more preferably 30 parts by mass or less, further preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and may be 0 parts by mass, based on 100 parts by mass of the rubber component, from the viewpoint of steering stability during high-speed driving. The content of the oil is also preferably in the same range. In this case, the content of the oil includes the oil contained in the extension oil.

[0099] Examples of the oil include process oil, vegetable oil, or a mixture thereof. Examples of the process oil include paraffin-based process oil, aromatic process oil, and naphthenic process oil. Examples of the vegetable oil include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. Examples of commercially available products include products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., Ltd., H&R Co., Ltd., Toyokuni Oil Mill Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kosan Co., Ltd., and Nisshin Oillio Group Co., Ltd. Among these, process oils (paraffin-based process oils, aromatic process oils, naphthenic process oils, etc.) and vegetable oils are preferred.

[0100] Examples of liquid resins include terpene resins (including terpene phenol resins and aromatic modified terpene resins), rosin resins, styrene resins, C5 resins, C9 resins, C5 / C9 resins, dicyclopentadiene (DCPD) resins, coumarone-indene resins (including coumarone and indene simple resins), phenol resins, olefin resins, polyurethane resins, acrylic resins, etc. Hydrogenated products of these resins can also be used.

[0101] Examples of liquid diene polymers include liquid styrene butadiene copolymers (liquid SBR), liquid butadiene polymers (liquid BR), liquid isoprene polymers (liquid IR), liquid styrene isoprene copolymers (liquid SIR), liquid styrene butadiene styrene block copolymers (liquid SBS block polymers), liquid styrene isoprene styrene block copolymers (liquid SIS block polymers), liquid farnesene polymers, and liquid farnesene butadiene copolymers that are in a liquid state at 25°C. The ends or main chains of these may be modified with polar groups. Hydrogenated versions of these may also be used.

[0102] Examples of the resins (resins in a solid state at room temperature (25°C)) that can be used in the rubber composition include aromatic vinyl polymers, coumarone-indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, and acrylic resins that are in a solid state at room temperature (25°C). The resins may be hydrogenated. These may be used alone or in combination of two or more. Of these, aromatic vinyl polymers, petroleum resins, and terpene resins are preferred.

[0103] When the rubber composition contains the resin, the content of the resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. By keeping the content within the above range, the steering stability during high-speed driving tends to be improved.

[0104] The softening point of the resin is preferably 60° C. or higher, more preferably 70° C. or higher, and even more preferably 80° C. or higher. The upper limit is preferably 160° C. or lower, more preferably 130° C. or lower, and even more preferably 115° C. or lower. By keeping the softening point within the above range, the handling stability during high-speed driving tends to be improved. The softening point of the resin is the temperature at which the ball drops when the softening point specified in JIS K6220-1:2001 is measured using a ring and ball softening point tester.

[0105] The aromatic vinyl polymer is a polymer containing an aromatic vinyl monomer as a structural unit. For example, it can be a resin obtained by polymerizing α-methylstyrene and / or styrene, and specifically, it can be a homopolymer of styrene (styrene resin), a homopolymer of α-methylstyrene (α-methylstyrene resin), a copolymer of α-methylstyrene and styrene, a copolymer of styrene and another monomer, etc.

[0106] The coumarone-indene resin is a resin containing coumarone and indene as main monomer components constituting the resin skeleton (main chain). Other monomer components contained in the skeleton besides coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, etc.

[0107] The coumarone resin is a resin containing coumarone as a main monomer component constituting the skeleton (main chain) of the resin.

[0108] The indene resin is a resin containing indene as a main monomer component constituting the skeleton (main chain) of the resin.

[0109] The phenolic resin may be a known polymer obtained by reacting phenol with an aldehyde such as formaldehyde, acetaldehyde, or furfural in the presence of an acid or alkali catalyst. Among these, those obtained by reacting with an acid catalyst (such as novolac-type phenolic resin) are preferred.

[0110] Examples of the rosin resin include rosin-based resins such as natural rosin, polymerized rosin, modified rosin, ester compounds thereof, and hydrogenated products thereof.

[0111] Examples of the petroleum resin include C5 resin, C9 resin, C5 / C9 resin, dicyclopentadiene (DCPD) resin, hydrogenated products thereof, etc. Among these, DCPD resin and hydrogenated DCPD resin are preferred.

[0112] The terpene resin is a polymer containing terpene as a structural unit. For example, polyterpene resin obtained by polymerizing a terpene compound, aromatic modified terpene resin obtained by polymerizing a terpene compound and an aromatic compound, etc. can be mentioned. Hydrogenated products of these can also be used.

[0113] The polyterpene resin is a resin obtained by polymerizing a terpene compound. The terpene compound is a polyterpene resin having a molecular weight of 1,000 to 1,0 .... 5 H 8 ) n The hydrocarbons and their oxygen-containing derivatives represented by the composition 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 ), and examples thereof include α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0114] Examples of the polyterpene resin include pinene resin, limonene resin, dipentene resin, pinene / limonene resin, etc., which are made from the above-mentioned terpene compounds. Among them, pinene resin is preferable. Pinene resin usually contains both α-pinene and β-pinene, which are isomers, but depending on the components contained, it is classified into β-pinene resin mainly composed of β-pinene and α-pinene resin mainly composed of α-pinene.

[0115] Examples of the aromatic modified terpene resin include terpene phenol resins made from the above terpene compounds and phenolic compounds, and terpene styrene resins made from the above terpene compounds and styrene compounds. Terpene phenol styrene resins made from the above terpene compounds, phenolic compounds, and styrene compounds can also be used. Examples of the phenolic compounds include phenol, bisphenol A, cresol, and xylenol. Examples of the styrene compounds include styrene and α-methylstyrene.

[0116] The acrylic resin is a polymer containing an acrylic monomer as a constituent unit. For example, a styrene-acrylic resin having a carboxyl group and obtained by copolymerizing an aromatic vinyl monomer component and an acrylic monomer component, such as a styrene-acrylic resin, can be used. Among them, a solventless carboxyl group-containing styrene-acrylic resin can be preferably used.

[0117] The solvent-free carboxyl group-containing styrene-acrylic resin is a (meth)acrylic resin (polymer) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (methods described in U.S. Pat. No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Pat. No. 5,010,166, Toa Gosei Kenkyuu Nenpo TREND 2000 Vol. 3, p. 42-45, etc.) with minimal use of auxiliary raw materials such as polymerization initiators, chain transfer agents, and organic solvents. In this specification, (meth)acrylic means methacryl and acrylic.

[0118] Examples of the acrylic monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters such as 2-ethylhexyl acrylate, aryl esters, aralkyl esters, etc.), (meth)acrylamide, (meth)acrylic acid derivatives such as (meth)acrylamide derivatives, etc. (Meth)acrylic acid is a general term for acrylic acid and methacrylic acid.

[0119] Examples of the aromatic vinyl monomer component constituting the acrylic resin include aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene.

[0120] As the monomer components constituting the acrylic resin, other monomer components may be used in addition to the (meth)acrylic acid, (meth)acrylic acid derivatives, and aromatic vinyl.

[0121] Examples of the plasticizer that can be used include products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Co., Ltd.

[0122] (Other materials) From the viewpoints of crack resistance, ozone resistance, and the like, the rubber composition preferably contains an antioxidant.

[0123] The antiaging agent is not particularly limited, and examples thereof include naphthylamine-based antiaging agents such as phenyl-α-naphthylamine; diphenylamine-based antiaging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, Examples of the antioxidant include p-phenylenediamine antioxidants such as amines; quinoline antioxidants such as polymerized 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis, tris, and polyphenol antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine antioxidants and quinoline antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymerized 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products include, for example, products from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd.

[0124] In the rubber composition, the content of the antioxidant is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the rubber component. The content is preferably 7.0 parts by mass or less, more preferably 4.0 parts by mass or less.

[0125] The rubber composition preferably contains stearic acid. The content of stearic acid in the rubber composition is preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the rubber component.

[0126] As the stearic acid, any known stearic acid can be used, for example, products available from NOF Corporation, NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., and the like.

[0127] The rubber composition preferably contains zinc oxide. The content of zinc oxide in the rubber composition is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass, based on 100 parts by mass of the rubber component.

[0128] As the zinc oxide, any known zinc oxide can be used, for example, products available from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc.

[0129] The rubber composition may contain wax. The content of the wax in the rubber composition is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass, based on 100 parts by mass of the rubber component.

[0130] The wax is not particularly limited, and examples thereof include petroleum waxes, natural waxes, etc. Also, synthetic waxes obtained by refining or chemically treating multiple waxes can be used. These waxes may be used alone or in combination of two or more kinds.

[0131] Examples of petroleum waxes include paraffin wax and microcrystalline wax. Examples of natural waxes are not particularly limited as long as they are derived from resources other than petroleum, and include, for example, vegetable waxes such as candelilla wax, carnauba wax, Japan wax, rice wax, and jojoba wax; animal waxes such as beeswax, lanolin, and spermaceti; mineral waxes such as ozokerite, ceresin, and petrolactam; and refined products thereof. Examples of commercially available products include products from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Chemical Co., Ltd.

[0132] The rubber composition may contain a processing aid. Examples of processing aids include fatty acid metal salts, fatty acid amides, amide esters, silica surfactants, fatty acid esters, mixtures of fatty acid metal salts and amide esters, mixtures of fatty acid metal salts and fatty acid amides, etc. Commercially available products include those from Rhein Chemie and Struktol. These may be used alone or in combination of two or more. Among these, fatty acid metal salts are preferred.

[0133] Examples of fatty acids constituting the fatty acid metal salt include saturated or unsaturated fatty acids (preferably saturated or unsaturated fatty acids having 6 to 28 carbon atoms (more preferably 10 to 25 carbon atoms, and even more preferably 14 to 20 carbon atoms)), such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, behenic acid, and nervonic acid. These can be used alone or in combination of two or more. Of these, saturated fatty acids are preferred, and saturated fatty acids having 14 to 20 carbon atoms are more preferred.

[0134] Examples of metals constituting fatty acid metal salts include alkali metals such as potassium and sodium, alkaline earth metals such as magnesium, calcium and barium, zinc, nickel, molybdenum, etc. These may be used alone or in combination of two or more. Among these, zinc is preferred.

[0135] The content of the processing aid, based on 100 parts by mass of the rubber component, is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, even more preferably 2 parts by mass or more, and is preferably 8 parts by mass or less, more preferably 6 parts by mass or less, even more preferably 4 parts by mass or less.

[0136] It is preferable to compound sulfur into the rubber composition in that it forms an appropriate amount of crosslinked chains in the polymer chains and imparts good performance.

[0137] In the rubber composition, the amount of sulfur is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, and even more preferably 0.5 part by mass or more, based on 100 parts by mass of the rubber component. The amount is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.0 parts by mass or less.

[0138] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. Commercially available products include those from Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. These may be used alone or in combination of two or more kinds.

[0139] The rubber composition preferably contains a vulcanization accelerator. In the rubber composition, the content of the vulcanization accelerator is not particularly limited and may be freely determined according to the desired vulcanization speed and crosslink density, but is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit is preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, and even more preferably 5.0 parts by mass or less.

[0140] The type of vulcanization accelerator is not particularly limited, and any commonly used accelerator can be used. Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenyl guanidine, di-orthotolyl guanidine, and orthotolyl biguanidine. These may be used alone or in combination of two or more. Among them, sulfenamide-based, guanidine-based and benzothiazole-based vulcanization accelerators are preferred.

[0141] In addition to the above components, the rubber composition may contain compounding agents generally used in the tire industry, such as materials such as a mold release agent, as appropriate.

[0142] The rubber composition can be produced by any known method, for example, by kneading the above-mentioned components using a rubber kneading device such as an open roll or a Banbury mixer, followed by vulcanization.

[0143] In particular, from the viewpoint of steering stability during high-speed driving, the rubber composition is preferably produced by a production method including a step of mixing a rubber component, a filler, and a surfactant to produce a rubber-filler composite. In the step, the rubber component preferably contains an isoprene-based rubber, and the filler preferably contains silica. The surfactant preferably contains a nonionic surfactant, and more preferably contains a nonionic surfactant and an anionic surfactant. In particular, when an isoprene-based rubber, silica, a nonionic surfactant, and an anionic surfactant are used, a composite with high silica dispersibility is obtained.

[0144] The rubber-filler composite can be suitably produced, for example, by a method including a step of mixing rubber latex, a filler dispersion, and a surfactant. Among them, a production method including a step of mixing a surfactant and a filler dispersion to prepare a mixed liquid (step (1)), and a step of mixing the mixed liquid with rubber latex (step (2)) is preferred.

[0145] (Process (1)) The filler dispersion is a dispersion (slurry) in which the filler is dispersed in a solvent. The solvent is not particularly limited, and examples thereof include water and organic solvents such as alcohol, among which water is preferred.

[0146] The filler content (solid content) in the filler dispersion is not particularly limited, but is preferably 0.2 to 20 mass %, more preferably 0.5 to 10 mass %, and even more preferably 0.5 to 7 mass %.

[0147] In the above step (1), the method of mixing the surfactant and the filler dispersion to prepare a mixture can be, for example, a method of mixing the surfactant and the filler dispersion using a known stirring device such as a high-speed homogenizer, an ultrasonic homogenizer, a colloid mill, a blender mill, etc., and the mixture of the surfactant and the filler dispersion can be obtained by stirring thoroughly until the surfactant and the filler dispersion are sufficiently dispersed. The temperature and time when preparing the mixture can be appropriately set within the range usually used until the surfactant and the filler dispersion are sufficiently dispersed, and for example, 10 to 40°C and 3 to 120 minutes are preferable, and 15 to 30°C and 5 to 90 minutes are more preferable.

[0148] The amount of the surfactant is preferably 1 to 50 parts by mass relative to 100 parts by mass of the rubber latex (rubber solid content) used in the rubber-filler composite. The amount is more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. The amount is more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

[0149] The amount of the filler is preferably 1 to 100 parts by mass relative to 100 parts by mass of the rubber latex (solid content of rubber) used in the rubber-filler composite. The amount is more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, and particularly preferably 30 parts by mass or more. Also, it is more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, and particularly preferably 70 parts by mass or less. When silica is used as the filler, the amount of silica is also preferably in the same range.

[0150] (Process (2)) In the present invention, the next step (step (2)) is to mix the mixture obtained in step (1) with rubber latex.

[0151] As the rubber latex, for example, diene-based rubber latex such as natural rubber latex, modified natural rubber latex (saponified natural rubber latex, epoxidized natural rubber latex, etc.), synthetic diene-based rubber latex (latex such as butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), isoprene rubber, acrylonitrile butadiene rubber, ethylene vinyl acetate rubber, chloroprene rubber, vinylpyridine rubber, and butyl rubber) can be suitably used. These rubber latexes may be used alone or in combination of two or more. Among them, natural rubber latex, isoprene-based rubber latex such as isoprene rubber latex, SBR latex, and BR latex are preferred, and isoprene-based rubber latex is more preferred.

[0152] Natural rubber latex is collected as sap from natural rubber trees such as hevea trees, and contains water, proteins, lipids, inorganic salts, etc. in addition to rubber components, and the gel content in the rubber is thought to be due to the presence of a variety of impurities in combination. In the present invention, the natural rubber latex that can be used includes raw latex (field latex) obtained by tapping hevea trees, concentrated latex concentrated by centrifugation or creaming methods (refined latex, high ammonia latex to which ammonia has been added in the usual manner, LATZ latex stabilized with zinc oxide, TMTD, and ammonia, etc.), etc.

[0153] The pH of the rubber latex is preferably 8.5 or more, more preferably 9.5 or more. When the pH is 8.5 or more, the rubber latex is less likely to become unstable and is less likely to coagulate. The pH of the rubber latex is preferably 12.0 or less, more preferably 11.0 or less. When the pH is 12.0 or less, the rubber latex is less likely to deteriorate.

[0154] The rubber latex can be prepared by a conventionally known method, and various commercially available products can also be used. The rubber latex used preferably has a rubber solid content of 10 to 80% by mass, more preferably 20% by mass or more and 60% by mass or less.

[0155] In the above step (2), the method of mixing the mixed liquid obtained in step (1) with the rubber latex includes, for example, a method of putting the rubber in a known stirring device such as a high-speed homogenizer, an ultrasonic homogenizer, a colloid mill, or a blender mill, and dropping the mixed liquid obtained in step (1) while stirring, or a method of dropping the rubber latex into the mixed liquid obtained in step (1) while stirring, and by stirring sufficiently until the mixture is sufficiently dispersed, a mixture of the mixed liquid obtained in step (1) and the rubber (compounded latex) can be obtained. The temperature and time when preparing the mixture can be appropriately set within the range usually used until the mixed liquid obtained in step (1) and the rubber are sufficiently dispersed, but for example, 10 to 40°C and 3 to 120 minutes are preferable, and 15 to 30°C and 5 to 90 minutes are more preferable.

[0156] The pH of the mixture (compounded latex) obtained in the above step (2) is preferably 9.0 or more, more preferably 9.5 or more, and is preferably 12.0 or less, more preferably 11.5 or less. When the pH of the mixture (compounded latex) of the mixed liquid obtained in the above step (1) and the rubber latex is within this range, deterioration can be suppressed and the mixture can be stabilized.

[0157] The mixture (compounded latex) obtained in the above step (2) is coagulated as necessary, and the coagulated material (coagulated material containing coagulated rubber and filler) is filtered and dried by a known method, and after further drying, rubber kneading is performed using a two-axis roll, Banbury, etc. to obtain a composite (rubber-filler composite) in which the filler is sufficiently dispersed in the rubber matrix. The rubber-filler composite may contain other components within a range that does not impair the effect.

[0158] The coagulation is usually carried out by adding an acid to the mixture (mixed latex) obtained in the step (2). Examples of the acid for coagulation include sulfuric acid, hydrochloric acid, formic acid, and acetic acid. The temperature during coagulation is preferably 10 to 40°C.

[0159] During the coagulation, the pH of the mixture (compounded latex) obtained in the step (2) is preferably adjusted to 3-5, and more preferably 3-4.

[0160] In addition, a flocculant may be added for the purpose of controlling the state of coagulation (the size of the coagulated aggregated particles). As the flocculant, a cationic polymer or the like can be used.

[0161] A rubber-filler composite is prepared by the above-mentioned manufacturing method, and a rubber composition can be produced by, for example, kneading the rubber-filler composite and other components using a rubber kneading device such as an open roll or a Banbury mixer, followed by vulcanization.

[0162] As for the kneading conditions, in the base kneading step in which additives other than the vulcanizing agent and the vulcanization accelerator are kneaded, the kneading temperature is usually 50 to 200°C, preferably 80 to 190°C, and the kneading time is usually 30 seconds to 30 minutes, preferably 1 minute to 30 minutes. In the finish kneading step in which the vulcanizing agent and the vulcanization accelerator are kneaded, the kneading temperature is usually 100°C or lower, preferably room temperature to 80°C. Furthermore, the composition kneaded with the vulcanizing agent and the vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 120 to 200°C, preferably 140 to 180°C.

[0163] The rubber composition can be preferably used for each component of a pneumatic tire such as a cap tread, a base tread, a sidewall, a bead apex, a clinch apex, an inner liner, an undertread, a breaker topping, a ply topping, an insert (sidewall reinforcing layer), etc. Among them, the rubber composition can be preferably used for a cap tread and a base tread.

[0164] A tire is manufactured by a conventional method using a rubber composition. That is, the rubber composition containing the above-mentioned components is extruded in an unvulcanized state to match the shape of a cap tread, a base tread, etc., and molded together with other tire components in a conventional manner on a tire building machine to form an unvulcanized tire. The unvulcanized tire is heated and pressurized in the vulcanizer to obtain a tire.

[0165] Examples of the tire include pneumatic tires and non-pneumatic tires. Among them, pneumatic tires are preferred. The tire can be used as a passenger car tire, a large passenger car tire, a large SUV tire, a heavy load tire such as a truck or a bus tire, a light truck tire, a two-wheeled vehicle tire, a racing tire (high performance tire), a run-flat tire, etc. Among them, it can be preferably used as a passenger car tire. EXAMPLES

[0166] The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0167] Various chemicals used in the examples and comparative examples will be collectively described below. NR:TSR20 Natural rubber latex: Field latex obtained from Muhibbah LATEKS. Silica 1: Degussa 9100Gr (N 2 SA235m 2 / g) Silica 2: Ultrasil VN3 (N) manufactured by Evonik Degussa 2 SA175m 2 / g) Surfactant 1: Emanon 4110 manufactured by Kao Corporation (non-ionic surfactant (ester type), polyethylene glycol monooleate, HLB 11.6, EO number 10) Surfactant 2: Emulgen 409P manufactured by Kao Corporation (non-ionic surfactant (ether type), polyoxyethylene oleyl ether, HLB 12, EO number 9, Mw 2000) Surfactant 3: NUOSPERSE FX 600 manufactured by Elementis (anionic surfactant, polycarboxylate amine salt (containing a phenyl group as a hydrophobic group and a carboxyl group as a hydrophilic group), Mw 2000) Carbon black: Mitsubishi Chemical's N220 (N 2 SA114m 2 / g) Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. Antioxidant 6C: Nocrac 6C (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) (6PPD) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Anti-aging agent RD: Nocrac RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: Camellia made by NOF Corporation Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Processing aid: EF44 (zinc salt of saturated fatty acid) manufactured by Struktol Silane coupling agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa Oil: Diana Process NH-70S (aromatic process oil) manufactured by Idemitsu Kosan Co., Ltd. Sulfur: HK-200-5 (powdered sulfur containing 5% oil by mass) manufactured by Hosoi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Sancerer NS-G (N-tert-butyl-2-benzothiazole sulfenamide) manufactured by Sanshin Chemical Industry Co., Ltd. Vulcanization accelerator 2: Sancerer D (diphenyl guanidine) manufactured by Sanshin Chemical Industry Co., Ltd.

[0168] (Preparation of Silica Dispersion) 190 g of pure water was added to 10 g of silica to prepare a 5 mass % (solid content concentration) silica suspension, which was stirred and subjected to ultrasonic treatment for 10 minutes to obtain a silica dispersion.

[0169] (Preparation of mixed solution (silica / surfactant)) Each mixed solution (silica / surfactant) was prepared according to the formulation in Table 1. Specifically, a surfactant was added to the prepared silica dispersion, and the mixture was stirred at room temperature (20 to 30°C) for 5 minutes using a high-speed homogenizer to obtain a mixture (mixture) of the silica dispersion and the surfactant.

[0170] [Table 1]

[0171] (Preparation of rubber-filler composite) Each rubber-filler composite (MB-1 to MB-4) was manufactured according to the compounding recipe in Table 2. Specifically, the prepared mixture was added to natural rubber latex and stirred at room temperature for 5 minutes using a high-speed homogenizer to obtain a compounded latex with a pH of 10.2. Next, a 2% by mass aqueous solution of formic acid was added at room temperature to adjust the pH to 3-4, obtaining a coagulated product. The obtained coagulated product was filtered and dried to obtain a rubber-filler composite.

[0172] [Table 2]

[0173] <Preparation of compounded rubber (unvulcanized rubber composition, vulcanized rubber composition)> Chemicals other than sulfur and vulcanization accelerator were kneaded using a 1.7 L Banbury mixer according to the compounding recipe in Table 3. Next, sulfur and vulcanization accelerator were added to the kneaded mixture using a roll and kneaded to obtain an unvulcanized rubber composition. The unvulcanized rubber composition thus obtained was then press-vulcanized at 170° C. for 15 minutes to obtain a vulcanized rubber composition.

[0174] The unvulcanized rubber compositions and vulcanized rubber compositions thus prepared were measured for their physical properties as described below. The results are shown in Table 3.

[0175] (Mooney Viscosity V) The unvulcanized rubber composition thus obtained was measured for its Mooney viscosity V (ML) at 4 minutes after rotating the small rotor at a temperature of 130°C, which was preheated for 1 minute, in accordance with JIS K 6300-1 "Unvulcanized rubber - Physical properties - Part 1: Determination of viscosity and scorch time using a Mooney viscometer." 1+4 / 130℃) was measured.

[0176] (Viscoelasticity measurement (E * (30℃) The obtained vulcanized rubber composition was subjected to the complex elastic modulus E under the conditions of temperature 30°C, initial strain 5%, dynamic strain ±1%, and frequency 10 Hz using an Iplexer manufactured by GABO. * was measured.

[0177] <Tire manufacturing> According to the compounding recipe in Table 3, chemicals other than sulfur and vulcanization accelerator were kneaded for 4 minutes at 150°C using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd., and then sulfur and vulcanization accelerator were added, and the mixture was kneaded for 5 minutes at 80°C using an open roll to prepare an unvulcanized rubber composition. Thereafter, the unvulcanized rubber composition was molded into a cap tread shape, laminated together with other tire components on a tire building machine, and press-vulcanized for 20 minutes at 170°C to prepare a test tire (195 / 65R15).

[0178] The test tires thus produced were evaluated according to the following methods, and the results are shown in Table 3.

[0179] (Stability during high speed driving) The test tires were fitted to all wheels of a domestic FF 2000cc vehicle, which was driven around a test course at a speed of 100km / h. The handling stability was evaluated by the drivers' sensory evaluation while the vehicle was meandering. Based on the feelings of 10 drivers, each vehicle was rated on a 10-point scale. The total score was calculated as a rating, and the standard comparative example was assigned a score of 100, which was then converted into an index. The higher the index, the better the handling stability during high-speed driving.

[0180] [Table 3]

[0181] From Tables 1 to 3, the above formula (1) "(1) V / E * The tires of the examples which satisfied the condition "≦3.0" had excellent handling stability during high-speed driving.

Claims

1. Mooney viscosity V, complex modulus E ＊ A rubber composition in which [MPa] satisfies the following formula (1): (1) V / E ＊ ≦2.7 (Wherein, V is the Mooney viscosity ML at a temperature of 130° C. １＋４ Represents E. ＊ represents the complex modulus of elasticity under the conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of ±1%, and a frequency of 10 Hz. Contains a rubber component and a filler, The rubber composition has a filler content of 5 parts by mass or more and 200 parts by mass or less based on 100 parts by mass of the rubber component.

2. A rubber composition having a Mooney viscosity V and a complex modulus E* [MPa] that satisfy the following formula (1): (1) V / E * ≦3.0 (In the formula, V represents the Mooney viscosity ML 1+4 at a temperature of 130° C., and E* represents the complex modulus of elasticity under the conditions of a temperature of 30° C., an initial strain of 5%, a dynamic strain of ±1%, and a frequency of 10 Hz.) Contains a rubber component and a filler, an amount of the filler relative to 100 parts by mass of the rubber component is 5 parts by mass or more and 200 parts by mass or less; Nitrogen adsorption specific surface area: 190 m ２ / g or more of silica.

3. A rubber composition having a Mooney viscosity V and a complex modulus E* [MPa] that satisfy the following formula (1): (1) V / E * ≦3.0 (In the formula, V represents the Mooney viscosity ML 1+4 at a temperature of 130° C., and E* represents the complex modulus of elasticity under the conditions of a temperature of 30° C., an initial strain of 5%, a dynamic strain of ±1%, and a frequency of 10 Hz.) Contains a rubber component and a filler, an amount of the filler relative to 100 parts by mass of the rubber component is 5 parts by mass or more and 200 parts by mass or less; A rubber composition comprising a nonionic surfactant and an anionic surfactant.

4. A rubber composition having a Mooney viscosity V and a complex modulus E* [MPa] that satisfy the following formula (1): (1) V / E * ≦3.0 (In the formula, V represents the Mooney viscosity ML 1+4 at a temperature of 130° C., and E* represents the complex modulus of elasticity under the conditions of a temperature of 30° C., an initial strain of 5%, a dynamic strain of ±1%, and a frequency of 10 Hz.) The Mooney viscosity V satisfies the following formula: V≦40.0 Contains a rubber component and a filler, The rubber composition has a filler content of 5 parts by mass or more and 200 parts by mass or less based on 100 parts by mass of the rubber component.

5. A rubber composition described in any one of claims 1, 2, or 4, comprising at least one selected from the group consisting of nonionic surfactants and anionic surfactants.

6. A rubber composition described in any one of claims 1, 2, or 4, comprising a nonionic surfactant and an anionic surfactant.

7. 7. The rubber composition according to claim 1, further comprising a composite obtained by mixing an isoprene-based rubber, silica, a nonionic surfactant, and an anionic surfactant.

8. The Mooney viscosity V and the complex elastic modulus E ＊ The rubber composition according to any one of claims 1 to 7, wherein [MPa] satisfies the following formula: V / E ＊ ≦2.2

9. The rubber composition according to any one of claims 1 to 3, wherein the Mooney viscosity V satisfies the following formula: V≦40.0

10. The complex elastic modulus E ＊ The rubber composition according to any one of claims 1 to 9, wherein [MPa] satisfies the following formula: E ＊ ≧8.0MPa

11. The rubber composition according to any one of claims 1 to 10, comprising at least one selected from the group consisting of an ether-type nonionic surfactant, an ester-type nonionic surfactant, and an ether ester-type nonionic surfactant.

12. The rubber composition according to any one of claims 1 to 10, comprising at least one selected from the group consisting of a carboxylic acid-based anionic surfactant, a sulfonic acid-based anionic surfactant, a sulfate ester-based anionic surfactant, and a phosphate ester-based anionic surfactant.

13. A composite obtained by a production method including a step of mixing a surfactant and a filler dispersion to prepare a mixed liquid, and a step of mixing the prepared mixed liquid with a rubber latex, The surfactant includes a nonionic surfactant and an anionic surfactant. The filler comprises silica, The rubber latex is a composite containing an isoprene-based rubber.

14. Nitrogen adsorption specific surface area: 190 m ２ 14. The composite of claim 13, comprising at least 1.0 g of silica.

15. A tire using the rubber composition according to any one of claims 1 to 12 or the composite according to any one of claims 13 to 14.

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