Tire internal member and tire

Abstract

A rubber composition comprising a rubber component, an inorganic fibrous material, and a coupling agent.

Description

Technical Field

[0001] The present invention relates to a tire having an inner member composed of a rubber composition containing an inorganic fiber material. to an object composed of tire inner member and an inner member of the tire having.

Background Art

[0002] There is known a technique of imparting anisotropy to the modulus of rubber by blending a bio-derived nano material such as cellulose fiber into a tire member (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is considered that rubber exhibits strength by forming a network structure, and anisotropy is easily obtained in fiber materials. However, if the dispersion state of the fiber material in the rubber matrix is poor, the fiber material aggregates, making it difficult to obtain anisotropy and insufficient reinforcement for the rubber matrix, resulting in a decrease in fracture strength. In addition, rubber compositions containing conventional fiber materials have a high elastic modulus and currently do not fully meet market requirements in terms of ride comfort and vibration.

[0005] An object of the present invention is to provide a rubber composition that highly achieves both fracture strength and anisotropy.

Means for Solving the Problems

[0006] As a result of intensive studies, the present inventors have found that a rubber composition having both high breaking strength and anisotropy can be obtained by blending an inorganic fiber material and a coupling agent, and have completed the present invention.

[0007] That is, the present invention relates to 〔1〕A rubber composition containing a rubber component, an inorganic fiber material, and a coupling agent, 〔2〕The rubber composition according to the above 〔1〕, wherein the ratio (M100a / M100b) of the 100% modulus M100a in the grain direction to the 100% modulus M100b in the transverse direction is 1.10 or more. 〔3〕The rubber composition according to the above 〔1〕 or 〔2〕, further containing carbon black (preferably 1 to 100 parts by mass, more preferably 5 to 80 parts by mass with respect to 100 parts by mass of the rubber component). 〔4〕The rubber composition according to any one of the above 〔1〕 to 〔3〕, further containing a plasticizer (preferably 1 to 90 parts by mass, more preferably 3 to 70 parts by mass with respect to 100 parts by mass of the rubber component). 〔5〕The rubber composition according to any one of the above 〔1〕 to 〔4〕, wherein the rubber component contains (preferably 5% by mass or more, more preferably 10 to 90% by mass) an isoprene-based rubber. 〔6〕The rubber composition according to any one of the above 〔1〕 to 〔5〕, wherein the coupling agent is a silane coupling agent. 〔7〕The rubber composition according to any one of the above 〔1〕 to 〔6〕, containing 1 to 40 parts by mass of the coupling agent with respect to 100 parts by mass of the rubber component. 〔8〕The rubber composition according to any one of the above 〔1〕 to 〔7〕, wherein the coupling agent is a silane coupling agent having a sulfide group. 〔9〕Further, cetyltrimethylammonium bromide adsorption specific surface area (CTAB) is 180 m 2 / g or less of carbon black (preferably 1 to 100 parts by mass, more preferably 5 to 80 parts by mass with respect to 100 parts by mass of the rubber component), the rubber composition according to any one of the above 〔1〕 to 〔8〕. 〔10〕The rubber composition according to any one of the above 〔1〕 to 〔9〕, which contains 1 to 50 parts by mass of the inorganic fiber material with respect to 100 parts by mass of the rubber component, wherein the average diameter D of the inorganic fiber material is 1.0 to 2000 nm, the average length L is 0.10 to 100 μm, and the aspect ratio L / D is 2 to 1000. 〔11〕The rubber composition according to any one of the above 〔1〕 to 〔10〕, wherein the inorganic fiber material is one or more inorganic fiber materials selected from the group consisting of magnesium sulfate fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, and sepiolite. 〔12〕A tire internal member composed of the rubber composition according to any one of the above 〔1〕 to 〔11〕. 〔13〕A tire provided with the tire internal member according to the above 〔12〕. 〔14〕The tire according to the above 〔13〕, wherein the tire is a passenger car tire.

Advantages of the Invention

[0008] According to the present invention, by blending an inorganic fiber material and a coupling agent, a rubber composition that highly balances both breaking strength and anisotropy is provided. Further, a tire provided with a tire internal member composed of the rubber composition has improved ride comfort and handling stability in good balance.

Embodiments for Carrying Out the Invention

[0009] Since the rubber composition of the present disclosure contains a rubber component, an inorganic fiber material, and a coupling agent, it exhibits excellent breaking strength and anisotropy.

[0010] Although not intended to be bound by theory, the following is considered as a mechanism by which the rubber composition of the present disclosure can exhibit excellent breaking strength and anisotropy.

[0011] By blending an inorganic fiber material into a rubber composition, anisotropy can be imparted to the modulus of the rubber. However, it is considered that the inorganic fiber material is less likely to disperse in the rubber component compared to fillers such as carbon black. Therefore, it is considered that the entire rubber matrix cannot be reinforced, and sufficient fracture strength and anisotropy are difficult to obtain. Thus, by blending a coupling agent together with the inorganic fiber material, the dispersibility of the inorganic fiber material in the rubber matrix can be improved, the entire matrix can be reinforced, and it becomes possible to orient in a uniform state. Therefore, it is considered that the anisotropy is also improved.

[0012] From the viewpoint of excellent anisotropy, the rubber composition (vulcanized rubber) of the present disclosure preferably has a value of the ratio of the 100% modulus M100a in the grain direction to the 100% modulus M100b in the anti-grain direction as an index of anisotropy (M100a / M100b, which may be referred to as the "modulus ratio" in this specification) of 1.10 or more, more preferably 1.15 or more, and even more preferably 1.20 or more. On the other hand, the upper limit value of the ratio of the moduli is not particularly limited, but is usually 2.00 or less, and may be 1.80 or less, 1.60 or less, or 1.50 or less. By setting the modulus ratio to 1.10 or more, it is possible to realize a flexible response with respect to the anti-grain direction of the inorganic fiber material oriented in a highly dispersed state by the coupling agent, and to increase the rigidity in the grain direction and improve the responsiveness. In this specification, the "grain direction" means the rolling direction when forming a sheet by extrusion or shear treatment, and the "anti-grain direction" means the direction perpendicular to the grain direction.

[0013] Also, when the rubber composition is used as a tire, the alignment direction of the inorganic fibers may be any of the circumferential direction, radial direction, and width direction of the tire. However, from the viewpoint of improving ride comfort and handling stability in a well-balanced manner, it is preferable that the inorganic fibers are aligned along the tire circumferential direction. When the inorganic fibers are oriented in the tire circumferential direction, a flexible response to the input (vibration) from the tire vertical direction during rolling is realized, and by increasing the rigidity in the orientation direction (tire circumferential direction), the responsiveness to the input during steering is improved. Therefore, it is considered that the ride comfort and handling stability are improved in a well-balanced manner.

[0014] The manufacturing procedure of a tire including the production of a rubber composition according to an embodiment of the present disclosure will be described in detail below. However, the following description is an exemplification for explaining the present disclosure and is not intended to limit the technical scope of the present invention only to this description scope. In this specification, when a numerical range is indicated using "~", it includes the numerical values at both ends thereof.

[0015] <Rubber component> Examples of rubber components that can be used in the present disclosure include diene rubbers such as isoprene rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), styrene-isoprene-butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR); non-diene rubbers such as ethylene-propylene-diene rubber (EPDM), butyl rubber (IIR), and halogenated butyl rubber (X-IIR). These may be used alone or in combination of two or more. The rubber component may be a rubber component containing at least one selected from the group consisting of isoprene rubber, SBR, and BR, a rubber component containing isoprene rubber, a rubber component containing isoprene rubber and BR, a rubber component consisting only of isoprene rubber and BR, a rubber component containing BR, a rubber component containing BR and SBR, a rubber component consisting only of BR and SBR, a rubber component containing isoprene rubber, SBR, and BR, or a rubber component consisting only of isoprene rubber, SBR, and BR.

[0016] The content of the diene rubber in 100% by mass of the rubber component is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 85% by mass or more. Also, it may be a rubber component consisting only of the diene rubber.

[0017] (Isoprene rubber) Examples of isoprene rubber include those commonly used in the tire industry such as isoprene rubber (IR) and natural rubber. Natural rubber includes, in addition to unmodified natural rubber (NR), modified natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber, and grafted natural rubber. These isoprene rubbers may be used alone or in combination of two or more.

[0018] NR is not particularly limited, and those commonly used in the tire industry can be used. For example, SIR20, RSS#3, TSR20, etc. can be mentioned.

[0019] When containing isoprene-based, the content 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 20% by mass or more, and particularly preferably 30% by mass or more from the viewpoint of breaking strength. On the other hand, the upper limit of the content in the isoprene-based rubber component is not particularly limited, but is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, and particularly preferably 75% by mass or less.

[0020] (SBR) SBR is not particularly limited. For example, solution-polymerized SBR (S-SBR), emulsion-polymerized SBR (E-SBR), modified SBRs thereof (modified S-SBR, modified E-SBR), etc. can be mentioned, and S-SBR is preferred. Examples of the modified SBR include SBR with a modified terminal and / or main chain, modified SBR coupled with tin, silicon compounds, etc. (condensates, those having a branched structure, etc.). Also, SBR can be classified into an oil-extended type with extender oil added to adjust flexibility and a non-oil-extended type without extender oil added, and either can be used. Examples of SBR include those manufactured and sold by JSR Corporation, Asahi Kasei Chemicals Corporation, Nippon Zeon Co., Ltd., etc. These SBRs can be used alone or in combination of two or more.

[0021] From the viewpoint of grip performance, the styrene content of SBR is preferably 15% by mass or more, more preferably 18% by mass or more, and still more preferably 20% by mass or more. Also, from the viewpoints of polymer dispersibility and low fuel consumption performance, it is preferably 60% by mass or less, more preferably 55% by mass or less, and still more preferably 50% by mass or less. In this specification, the styrene content of SBR is 1 calculated by H-NMR measurement.

[0022] When contained in SBR, the content 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 from the viewpoint of wear resistance performance. Further, the upper limit of the content of SBR in the rubber component is not particularly limited, but is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, and particularly preferably 75% by mass or less.

[0023] (BR) BR is not particularly limited. For example, BR with a cis-1,4 bond content (cis content) of less than 50% (low-cis BR), BR with a cis-1,4 bond content of 90% or more (high-cis BR), rare earth-based butadiene rubber synthesized using a rare earth element-based catalyst (rare earth-based BR), BR containing syndiotactic polybutadiene crystals (SPB-containing BR), modified BR (high-cis modified BR, low-cis modified BR), etc., which are common in the tire industry, can be used. These BRs may be used alone or in combination of two or more.

[0024] The cis-1,4 bond content of high-cis BR is preferably 95% or more, more preferably 97% or more. By containing high-cis BR, the low-temperature properties and wear resistance performance can be improved. Examples of high-cis BR include high-cis BR manufactured and sold by Nippon Zeon Co., Ltd., Ube Industries, Ltd., JSR Corporation, etc. Examples of rare earth-based BR include rare earth-based BR manufactured and sold by Lanxess Co., Ltd., etc.

[0025] SPB-containing BR refers to a material in which 1,2-syndiotactic polybutadiene crystals are not simply dispersed in BR but are dispersed after being chemically bonded to BR. Examples of SPB-containing BR include SPB-containing BR manufactured and sold by Ube Industries, Ltd., etc.

[0026] Examples of the modified BR include those obtained by polymerizing 1,3-butadiene with a lithium initiator and then adding a tin compound, in which the terminals of the modified BR molecules are bonded by tin-carbon bonds (tin-modified BR), and butadiene rubber having a condensed alkoxysilane compound at the active terminals of the butadiene rubber (modified BR for silica). Examples of such modified BR include tin-modified polymers manufactured by ZS Elastomer Co., Ltd., S-modified polymers (modified for silica), and the like.

[0027] From the viewpoint of abrasion resistance performance, the content of BR in 100% by mass of the rubber component when contained is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, still more preferably 20% by mass or more, and particularly preferably 25% by mass or more. The upper limit of the content of BR in the rubber component is not particularly limited, but is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, and particularly preferably 75% by mass or less.

[0028] <Inorganic fiber material> The rubber composition according to the present disclosure contains an inorganic fiber material. By imparting anisotropy to the strength and rigidity with the inorganic fiber material oriented in the tire circumferential direction, a flexible response to the input (vibration) from the tire vertical direction during rolling is realized, and by increasing the rigidity in the orientation direction (tire circumferential direction), the responsiveness to the input during steering is improved.

[0029] The inorganic fiber material that can be used in the present disclosure is not particularly limited. Examples thereof include magnesium sulfate fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, sepiolite, glass fiber, and the like. One or more inorganic fiber materials selected from the group consisting of magnesium sulfate fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, and sepiolite are preferable, and magnesium sulfate fiber is more preferable. The above-mentioned inorganic fiber materials may be used alone or in combination of two or more.

[0030] As the magnesium sulfate fiber, MgSO4 ·5Mg(OH) 2 ·3H 2 O-represented basic magnesium sulfate fiber is preferred. As the calcium silicate fiber, 6CaO·6SiO 2 ·H 2 O-represented calcium silicate fiber is preferred. As the potassium titanate fiber, K 2 O·6TiO 2 Or K 2 O·8TiO 2 -represented potassium titanate fiber is preferred. As the aluminum borate fiber, 9Al 2 O 3 ·2B 2 O 3 -represented aluminum borate is preferred. As the sepiolite, Mg 8 Si 12 O 30 (OH) 4 (H 2 O) 4 ·8H 2 O-represented sepiolite is preferred.

[0031] The inorganic fiber material may be a commercially available one or a product manufactured by a known production method. Specific examples of the inorganic fiber material include, for example, inorganic fiber materials manufactured and sold by Ube Materials Co., Ltd., Otsuka Chemical Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Omi Mining Co., Ltd., etc.

[0032] From the viewpoint of the anisotropy of the rubber composition, the content of the inorganic fiber material with respect to 100 parts by mass of the rubber component is preferably 1.0 part by mass or more, more preferably 1.5 part by mass or more, further preferably 2.0 part by mass or more, and particularly preferably 2.5 part by mass or more. Also, from the viewpoint of the breaking strength of the rubber composition, it is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, further preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

[0033] The average diameter D of the inorganic fiber material (also referred to as the average fiber diameter or average width) is preferably 1.0 nm or more, more preferably 2.0 nm or more, and even more preferably 3.0 nm or more from the viewpoints of the rigidity and processability of the rubber composition. Further, from the viewpoints of the rigidity and fracture strength of the rubber composition, it is preferably 2000 nm or less, more preferably 1000 nm or less, even more preferably 500 nm or less, and particularly preferably 100 nm or less.

[0034] The average length L of the inorganic fiber material (also referred to as the average fiber length) is preferably 0.10 μm or more, more preferably 0.15 μm or more, even more preferably 0.20 μm or more, and particularly preferably 0.50 μm or more from the viewpoint of the anisotropy of the rubber composition. Further, from the viewpoints of the rigidity and fracture strength of the rubber composition, it is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and particularly preferably 40 μm or less.

[0035] In the present disclosure, the average diameter D and the average length L can be measured by image analysis of a scanning electron micrograph, image analysis of a transmission micrograph, analysis of X-ray scattering data, the pore electrical resistance method (Coulter principle method), or the like.

[0036] The aspect ratio L / D of the inorganic fiber material is preferably 2 or more, more preferably 4 or more, even more preferably 6 or more, and particularly preferably 8 or more from the viewpoint of the anisotropy of the rubber composition. Further, from the viewpoint of the fracture strength of the rubber composition, it is preferably 1000 or less, more preferably 500 or less, even more preferably 250 or less, and particularly preferably 100 or less.

[0037] <Coupling agent> The rubber composition according to the present disclosure contains a coupling agent. Although the inorganic fiber material is less likely to be dispersed in the rubber component compared to fillers such as carbon black, the dispersibility of the inorganic fiber material is improved by blending a coupling agent, and the anisotropy is also improved.

[0038] Coupling agents that can be used in the present disclosure are not particularly limited, and examples include silane coupling agents that bind to silica and rubber components, carbon coupling agents that bind to carbon black and rubber components, and the like.

[0039] (Silane coupling agent) The silane coupling agent is not particularly limited, and any silane coupling agent that has been conventionally used in combination with silica in the rubber industry can be used. For example, silane coupling agents having the following mercapto groups; sulfide group-containing silane coupling agents such as bis(3-triethoxysilylpropyl) disulfide and bis(3-triethoxysilylpropyl) tetrasulfide; vinyl group-containing silane coupling agents such as vinyltriethoxysilane and vinyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2-aminoethyl)aminopropyltriethoxysilane; glycidoxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silane coupling agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane, etc. Among them, silane coupling agents having a sulfide group and / or a mercapto group are preferred, and silane coupling agents having a sulfide group are more preferred. These silane coupling agents may be used alone or in combination of two or more.

[0040] The silane coupling agent having a mercapto group is preferably a compound represented by the following formula (1) and / or a compound containing a bonding unit A represented by the following formula (2) and a bonding unit B represented by the following formula (3).

Chemical formula

[0041] Examples of the compound represented by the formula (1) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and the compound represented by the following chemical formula (4) (Si363 manufactured by Evonik Degussa), etc. Among them, the compound represented by the following chemical formula (4) can be preferably used. These may be used alone or in combination of two or more. [Chemical formula]

[0042] Examples of the compound containing the linking unit A represented by the formula (2) and the linking unit B represented by the formula (3) include those manufactured and sold by Momentive Co., Ltd. and the like. These may be used alone or in combination of two or more.

[0043] (Carbon coupling agent) The carbon coupling agent is not particularly limited, but examples include tetrasulfide compounds such as bis(dimethylaminoethyl)tetrasulfide (DME) and bis(dimethylaminopropyl)tetrasulfide (DMP); benzimidazole compounds such as 1,2-bis(benzimidazolyl-2)ethane (EBZ) and 1,4'-bis(mercaptobenzimidazolyl-2)butane (C4SBZ); metal salts of pyrithione and the like. These carbon coupling agents may be used alone or in combination of two or more.

[0044] From the viewpoint of enhancing the dispersibility of the inorganic fiber material, the content of the coupling agent (preferably a silane coupling agent) relative to 100 parts by mass of the rubber component is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, and still more preferably 2.0 parts by mass or more. From the viewpoint of the breaking strength, it is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

[0045] When the content of the inorganic fiber material relative to 100 parts by mass of the rubber component is A (parts by mass), the content of silica is B (parts by mass), and the content of the coupling agent (preferably a silane coupling agent) is X (parts by mass), it is preferable that A, B, and X satisfy the following formula (5). 0.09A + 0.08B ≤ X ≤ 0.35A + 0.08B ···(5)

[0046] <Filler> The above rubber composition can be blended with fillers generally used in the conventional rubber industry, such as carbon black, silica, aluminum hydroxide, calcium carbonate, alumina, clay, talc, etc. Among them, it is preferably contained carbon black, and more preferably contains carbon black and silica.

[0047] Since carbon black has a high heat generation property during mixing, it is considered that it can promote plasticization during mixing and enable the inorganic fiber material to react with the coupling agent and be easily dispersed in the rubber matrix. At the same time, unlike the inorganic fiber material, it can obtain a reinforcing effect without anisotropy, so it is possible to impart the minimum required breaking strength in the direction of the anti-alignment of the inorganic fibers. On the other hand, although silica has a weaker reinforcing effect than carbon black and inorganic fiber materials, it can reinforce flexibly, so it is considered that it is possible to reinforce the entire rubber matrix while ensuring the flexibility in the anti-alignment direction.

[0048] (Carbon black) The carbon black is not particularly limited, and those common in the tire industry, such as GPF, FEF, HAF, ISAF, SAF, etc., can be used. Specifically, N110, N115, N120, N125, N134, N135, N219, N220, N231, N234, N293, N299, N326, N330, N339, N343, N347, N351, N356, N358, N375, N539, N550, N582, N630, N642, N650, N660, N683, N754, N762, N765, N772, N774, N787, N907, N908, N990, N991, etc. can be preferably used. In addition, self-made synthetic products, etc. can also be preferably used. These carbon blacks may be used alone or in combination of two or more.

[0049] The nitrogen adsorption specific surface area (N 2 SA) of carbon black is preferably 30 m 2 / g or more from the viewpoints of weather resistance and reinforcing property, and 35 m 2More preferably, it is 40 m / g or more, and even more preferably 40 m / g or more. Further, from the viewpoints of dispersibility, low fuel consumption performance, fracture characteristics, and durability, it is preferably 250 m / g or less, more preferably 220 m / g or less. The NSA of carbon black in this specification is a value measured in accordance with Method A of JIS K 6217-2:2017 "Carbon black for rubber - Basic characteristics - Part 2: Method for determining specific surface area - Nitrogen adsorption method - Single point method". 2 From the viewpoints of dispersibility, low fuel consumption performance, fracture characteristics, and durability, it is preferably 250 m / g or less, more preferably 220 m / g or less. 2 Preferably, it is 220 m / g or less, and more preferably 220 m / g or less. 2 The CTAB of carbon black is preferably 180 m / g or less, more preferably 165 m / g or less, and even more preferably 150 m / g or less from the viewpoint of ensuring the anisotropy of the rubber composition without the rubber network becoming excessively strong. On the other hand, the lower limit value of CTAB of carbon black is not particularly limited, but from the viewpoint of reinforcement, it is preferably 30 m / g or more, more preferably 40 m / g or more, and even more preferably 50 m / g or more. Here, CTAB is a value correlated with the particle size of carbon black, and the larger the CTAB, the smaller the particle size of carbon black. The CTAB of carbon black in this specification is a value measured in accordance with JIS K 6217-3:2001 "Carbon black for rubber - Basic characteristics - Part 3: Method for determining specific surface area - CTAB adsorption method". 2 The NSA of carbon black in this specification is a value measured in accordance with Method A of JIS K 6217-2:2017 "Carbon black for rubber - Basic characteristics - Part 2: Method for determining specific surface area - Nitrogen adsorption method - Single point method".

[0050] The cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of carbon black is preferably 180 m / g or less, more preferably 165 m / g or less, and even more preferably 150 m / g or less from the viewpoint of ensuring the anisotropy of the rubber composition without the rubber network becoming excessively strong. 2 Preferably, it is 165 m / g or less, and more preferably 165 m / g or less. 2 More preferably, it is 150 m / g or less, and even more preferably 150 m / g or less. 2 On the other hand, the lower limit value of CTAB of carbon black is not particularly limited, but from the viewpoint of reinforcement, it is preferably 30 m / g or more, more preferably 40 m / g or more, and even more preferably 50 m / g or more. Here, CTAB is a value correlated with the particle size of carbon black, and the larger the CTAB, the smaller the particle size of carbon black. The CTAB of carbon black in this specification is a value measured in accordance with JIS K 6217-3:2001 "Carbon black for rubber - Basic characteristics - Part 3: Method for determining specific surface area - CTAB adsorption method". 2 Preferably, it is 30 m / g or more, and more preferably 40 m / g or more. 2 More preferably, it is 40 m / g or more, and even more preferably 40 m / g or more. 2 Even more preferably, it is 50 m / g or more. Here, CTAB is a value correlated with the particle size of carbon black, and the larger the CTAB, the smaller the particle size of carbon black. The CTAB of carbon black in this specification is a value measured in accordance with JIS K 6217-3:2001 "Carbon black for rubber - Basic characteristics - Part 3: Method for determining specific surface area - CTAB adsorption method".

[0051] When containing carbon black, the content per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more from the viewpoints of weather resistance and reinforcement. Further, from the viewpoint of low fuel consumption performance, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less.

[0052] (Silica) The silica is not particularly limited, and for example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), etc., which are common in the tire industry, can be used. Among them, hydrous silica prepared by a wet method is preferred because it has many silanol groups. These silicas may be used alone or in combination of two or more.

[0053] The nitrogen adsorption specific surface area (N 2 SA) of the silica is preferably 140 m 2 / g or more, more preferably 150 m 2 / g or more, even more preferably 160 m 2 / g or more, particularly preferably 170 m 2 / g or more, from the viewpoints of low fuel consumption performance and wear resistance. Also, from the viewpoints of low fuel consumption performance and processability, it is preferably 350 m 2 / g or less, more preferably 300 m 2 / g or less, even more preferably 250 m 2 / g or less. The N 2 SA of the silica in this specification is a value measured by the BET method in accordance with ASTM D3037-93.

[0054] The content of silica relative to 100 parts by mass of the rubber component when containing silica is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, particularly preferably 20 parts by mass or more, from the viewpoint of low fuel consumption performance. Also, from the viewpoint of processability, it is preferably 110 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 90 parts by mass or less, particularly preferably 80 parts by mass or less.

[0055] The total content of silica and carbon black relative to 100 parts by mass of the rubber component is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, particularly preferably 35 parts by mass or more, from the viewpoint of reinforcement. Also, from the viewpoint of processability, it is preferably 200 parts by mass or less, more preferably 170 parts by mass or less, even more preferably 150 parts by mass or less, particularly preferably 130 parts by mass or less.

[0056] The content ratio of silica in the total content of silica and carbon black is preferably 50% or more, more preferably 70% or more, and even more preferably 80% or more.

[0057] The content of the inorganic fiber material in the total content of the inorganic fiber material, silica, and carbon black is preferably 5% by mass or more, and more preferably 8% by mass or more. Thereby, the anisotropic effect by the inorganic fiber material is easily obtained. On the other hand, the content of the inorganic fiber material in the total content of the inorganic fiber material, silica, and carbon black is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. Thereby, it is possible to prevent the rubber phase from being reinforced only in the columnar direction and the strength from extremely weakening in the anti-columnar direction.

[0058] <Other compounding agents> In addition to the above components, the rubber composition may appropriately contain compounding agents generally used in the conventional tire industry, such as plasticizers, waxes, anti-aging agents, stearic acid, zinc oxide, vulcanizing agents such as sulfur, and vulcanization accelerators. It is preferable to contain a plasticizer. By containing a plasticizer, the viscosity of the rubber is reduced during mixing, and the inorganic fiber material is easily dispersed, so that the anisotropy and the breaking strength tend to be improved. Examples of the plasticizer include oils, resin components, liquid rubbers, and the like.

[0059] Examples of the oil include mineral oils such as aromatic oil, process oil, and paraffin oil. Among them, it is preferable to use process oil for the reason of reducing the environmental load.

[0060] When contained, the content relative to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more from the viewpoint of processability. Further, from the viewpoint of abrasion resistance performance, it is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 60 parts by mass or less, and particularly preferably 50 parts by mass or less. In the present specification, the oil content includes the amount of oil contained in the oil-extended rubber.

[0061] The resin component is not particularly limited, and examples thereof include petroleum resins, terpene resins, rosin resins, phenolic resins, etc. commonly used in the tire industry. Examples of the petroleum resin include C5-based petroleum resins, aromatic petroleum resins, C5C9-based petroleum resins, etc. These resin components may be used alone or in combination of two or more.

[0062] In the present specification, the "C5-based petroleum resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of the C5 fraction include petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, and isoprene. As the C5-based petroleum resin, dicyclopentadiene resin (DCPD resin) is preferably used.

[0063] In the present specification, the "aromatic petroleum resin" refers to a resin obtained by polymerizing a C9 fraction, and those obtained by hydrogenating or modifying them may also be used. Examples of the C9 fraction include petroleum fractions corresponding to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, and methylindene. Specific examples of the aromatic petroleum resin include, for example, Coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl resin are preferably used. As the aromatic vinyl resin, due to economic reasons, ease of processing, and excellent heat generation properties, a homopolymer of α-methylstyrene or styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred. As the aromatic vinyl resin, for example, those commercially available from companies such as Kreton and Eastman Chemical can be used.

[0064] In this specification, "C5C9 petroleum resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and those obtained by hydrogenating or modifying them may also be used. Examples of the C5 fraction and the C9 fraction include the above-mentioned petroleum fractions. As the C5C9 petroleum resin, for example, those commercially available from Tosoh Corporation, LUHUA, etc. can be used.

[0065] Examples of terpene resins include polyterpene resins composed of at least one selected from terpene compounds such as α-pinene, β-pinene, limonene, and dipentene; aromatic-modified terpene resins using the terpene compounds and aromatic compounds as raw materials; terpene-phenol resins using terpene compounds and phenolic compounds as raw materials; and those obtained by subjecting these terpene resins to a hydrogenation treatment (hydrogenated terpene resins). Examples of the aromatic compounds used as raw materials for aromatic-modified terpene resins include styrene, α-methylstyrene, vinyltoluene, divinyltoluene, etc. Examples of the phenolic compounds used as raw materials for terpene-phenol resins include phenol, bisphenol A, cresol, xylenol, etc.

[0066] The rosin-based resin is not particularly limited, and examples include natural resin rosin and rosin-modified resins obtained by modifying it by hydrogenation, disproportionation, dimerization, esterification, etc.

[0067] The phenolic resin is not particularly limited, and examples thereof include phenol formaldehyde resin, alkylphenol formaldehyde resin, alkylphenol acetylene resin, oil-modified phenol formaldehyde resin, and the like.

[0068] When containing a resin component, the content thereof with respect to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass or more. Also, the content of the resin component is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 20 parts by mass or less.

[0069] The liquid rubber is not particularly limited as long as it is a polymer in a liquid state at normal temperature (25°C). Examples thereof include liquid butadiene rubber (liquid BR), liquid styrene-butadiene rubber (liquid SBR), liquid isoprene rubber (liquid IR), liquid styrene-isoprene rubber (liquid SIR), liquid farnesene rubber, and the like. These liquid rubbers may be used alone or in combination of two or more.

[0070] When containing a liquid rubber, the content thereof with respect to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass or more. Also, the content of the liquid rubber is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 20 parts by mass or less.

[0071] The content of the plasticizer with respect to 100 parts by mass of the rubber component (the total amount of all plasticizers when a plurality of plasticizers are used in combination) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more. Also, the content of the plasticizer is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 50 parts by mass or less, and particularly preferably 30 parts by mass or less. When the content of the plasticizer exceeds 90 parts by mass, softening of the entire rubber matrix by the plasticizer occurs, and sufficient reinforcing property by the inorganic fiber material cannot be obtained, so anisotropy and breaking strength tend to decrease.

[0072] When contained, the content relative to 100 parts by mass of the rubber component is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and still more preferably 1.5 part by mass or more from the viewpoint of the weather resistance of the rubber. Further, from the viewpoint of preventing whitening of the tire due to blooming, it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

[0073] The anti-aging agent is not particularly limited. Examples thereof include anti-aging agents such as amine-based, quinoline-based, quinone-based, phenol-based, and imidazole-based compounds, and metal carbamates. Preferred are phenylenediamine-based anti-aging agents such as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N,N'-bis(1-methylheptyl)-p-phenylenediamine, N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N-4-methyl-2-pentyl-N'-phenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, hindered diaryl-p-phenylenediamine, phenylhexyl-p-phenylenediamine, and phenyloctyl-p-phenylenediamine, and quinoline-based anti-aging agents such as 2,2,4-trimethyl-1,2-dihydroquinoline polymer and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline. These anti-aging agents may be used alone or in combination of two or more.

[0074] When contained, the content relative to 100 parts by mass of the rubber component is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and still more preferably 1.5 part by mass or more from the viewpoint of ozone crack resistance of the rubber. Further, from the viewpoints of abrasion resistance performance and wet grip performance, it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

[0075] When containing stearic acid, the content relative to 100 parts by mass of the rubber component is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and still more preferably 1.5 part by mass or more from the viewpoint of processability. Further, from the viewpoint of vulcanization rate, it is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less.

[0076] When containing zinc oxide, the content relative to 100 parts by mass of the rubber component is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and still more preferably 1.5 part by mass or more from the viewpoint of processability. Further, from the viewpoint of abrasion resistance performance, it is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less.

[0077] Sulfur is preferably used as the vulcanizing agent. As the sulfur, powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, etc. can be used.

[0078] When containing sulfur as the vulcanizing agent, the content relative to 100 parts by mass of the rubber component is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and still more preferably 1.5 part by mass or more from the viewpoint of ensuring a sufficient vulcanization reaction and obtaining good grip performance and abrasion resistance performance. Further, from the viewpoint of deterioration prevention, it is preferably 5.0 parts by mass or less, more preferably 4.5 parts by mass or less, and still more preferably 4.0 parts by mass or less.

[0079] Examples of vulcanizing agents other than sulfur include vulcanizing agents containing sulfur atoms such as Tackiol V-200 manufactured by Tago Chemical Industry Co., Ltd., DURALINK HTS (sodium 1,6-hexamethylene-dithiolsulfate dihydrate) manufactured by Flexsys, and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane) manufactured by Lanxess Co., Ltd., and organic peroxides such as dicumyl peroxide.

[0080] Although the vulcanization accelerator is not particularly limited, examples thereof include sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamic acid-based, aldehyde-amine-based or aldehyde-ammonia-based, imidazoline-based, and xanthate-based vulcanization accelerators. Among them, sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators are preferred from the viewpoint that the desired effects can be more preferably obtained, and it is more preferable to use these two types in combination.

[0081] Examples of the sulfenamide-based vulcanization accelerator include CBS (N-cyclohexyl-2-benzothiazolylsulfenamide), TBBS (N-t-butyl-2-benzothiazolylsulfenamide), N-oxyethylene-2-benzothiazolylsulfenamide, N,N'-diisopropyl-2-benzothiazolylsulfenamide, N,N-dicyclohexyl-2-benzothiazolylsulfenamide, and the like. Examples of the thiazole-based vulcanization accelerator include 2-mercaptobenzothiazole, dibenzothiazolyl disulfide, and the like. Examples of the thiuram-based vulcanization accelerator include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetrabenzylthiuram disulfide (TBzTD), and the like. Examples of the guanidine-based vulcanization accelerator include 1,3-diphenylguanidine (DPG), diorthotolylguanidine, orthotolylbiguanidine, and the like. These vulcanization accelerators may be used alone or in combination of two or more.

[0082] When containing a vulcanization accelerator, the content thereof with respect to 100 parts by mass of the rubber component is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, and further preferably 1.5 part by mass or more. Also, the content of the vulcanization accelerator with respect to 100 parts by mass of the rubber component is preferably 8 parts by mass or less, more preferably 7 parts by mass or less, and further preferably 6 parts by mass or less. By setting the content of the vulcanization accelerator within the above range, the breaking strength and elongation tend to be ensured.

[0083] [Method for Producing Rubber Composition and Tire] The rubber composition of the present disclosure can be produced by a known method. For example, using a known kneader such as a Banbury mixer, a kneader, an open roll, etc. used in the general rubber industry, among the above components, after kneading the components other than the vulcanizing agent and the vulcanization accelerator, the vulcanizing agent and the vulcanization accelerator are added thereto and further kneaded, and then vulcanized. For example, in the kneading step, knead at 80°C to 170°C for 1 minute to 30 minutes, and in the vulcanization step, vulcanize at 130°C to 190°C for 3 minutes to 20 minutes.

[0084] In the rubber composition of the present disclosure, when the inorganic fibers are oriented in the tire circumferential direction, a flexible response to the input (vibration) from the tire vertical direction during rolling is realized, and by increasing the rigidity in the orientation direction (tire circumferential direction), it is considered that the responsiveness to the input during steering is improved. Therefore, it can be suitably used for members continuous in the tire circumferential direction such as the cap tread, the base tread, the sidewall, the inner sidewall layer, the inner liner, the strip apex, the bead apex, the clinch apex, the bead reinforcement layer, the insulation, the insert, etc., and it is considered that the same effect can be obtained in any case. Among them, it is suitably used as a rubber composition for tire inner members such as the base tread, the inner sidewall layer, the inner liner, the strip apex, the bead apex, the bead reinforcement layer, the insulation, the insert, etc. By using the rubber composition of the present disclosure as such a tire inner member, it is considered that the handling stability and the riding comfort can be improved because the elasticity (responsiveness) of the tire in the rolling direction can be improved while maintaining the cushioning property.

[0085] In addition, in this specification, the "inner member" is not limited to the above-mentioned members, and refers to tire members other than the members that form the outer surface when the tire is mounted on the rim and filled with air.

[0086] The tire of the present disclosure can be manufactured by a conventional method using the above rubber composition. That is, an unvulcanized rubber composition in which each of the above components is blended with the rubber component as necessary is extruded according to the shape of the corresponding tire member to obtain a rubber composition in which the inorganic fiber material is oriented in the alignment direction. Then, the rubber composition is laminated together with other tire members on a tire molding machine so that the inorganic fiber material is oriented in the tire circumferential direction, and the unvulcanized tire is formed by molding in a conventional method. By heating and pressurizing this unvulcanized tire in a vulcanizer, the tire can be manufactured. The tire of the present disclosure may be a pneumatic tire or a non-pneumatic tire. Further, it is suitable for competition tires, passenger car tires, large passenger cars, large SUV tires, and motorcycle tires, and can be used as each summer tire, winter tire, and studless tire.

Examples

[0087] The present disclosure will be described based on examples, but the present disclosure is not limited to only the examples.

[0088] The following shows various chemicals used in the examples and comparative examples in a summary. NR: TSR20 BR: Ube Pol BR150B (cis content: 97%) manufactured by Ube Industries, Ltd. SBR1: Toughden 3830 (unmodified S-SBR, styrene content: 32% by mass, oil product containing 37.5% by mass of oil component with respect to 100 parts by weight of rubber component) manufactured by Asahi Kasei Corporation SBR2: Asapren 1205 (unmodified S-SBR, styrene content: 25% by mass) manufactured by Asahi Kasei Corporation Carbon black: Showblack N220 (CTAB: 110m 2 / g, N 2 SA: 111m 2 / g) Silica: ULTRASIL (registered trademark) VN3 (N 2 SA: 175m 2 / g) Inorganic fiber material 1: Mos High-Z (basic magnesium sulfate fiber, average fiber diameter: 500 - 1000 nm, average fiber length: 8 - 30 μm) manufactured by Ube Materials Co., Ltd. Inorganic fiber material 2: Sepiolite (average fiber diameter: 5 - 30 nm, average fiber length: 0.2 - 2.0 μm) Inorganic fiber material 3: Zono High-Z (calcium silicate fiber, average fiber diameter: 100 - 500 nm, average fiber length: 1 - 5 μm) manufactured by Ube Materials Co., Ltd. Silane coupling agent: Si69 (bis(3-triethoxysilylpropyl)tetrasulfide) manufactured by Evonik Degussa Oil: Process Oil X-140 manufactured by ENEOS Co., Ltd. Antioxidant: Ozone 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Seiko Chemical Co., Ltd. Stearic acid: Stearic acid "Tsubaki" manufactured by NOF Corporation Zinc oxide: Zinc white No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Wax: Oz Ace 0355 manufactured by Nippon Seiro Co., Ltd. Sulfur: Powder sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Soxinol CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Sumitomo Chemical Co., Ltd. Vulcanization accelerator 2: Soxinol D (1,3-diphenylguanidine) manufactured by Sumitomo Chemical Co., Ltd.

[0089] (Examples and Comparative Examples) According to the compounding formulations shown in Table 1 and Table 2, materials other than sulfur and vulcanization accelerators were kneaded using a Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded product. Next, sulfur and vulcanization accelerators were added to the obtained kneaded product, and it was kneaded using an open roll to obtain an unvulcanized rubber composition. An unvulcanized rubber sheet with a thickness of 0.5 mm was produced from the obtained unvulcanized rubber composition using an open roll. The obtained unvulcanized rubber sheets were stacked to form a 1.5-mm sheet, which was press-vulcanized at 150 °C for 15 minutes to produce a vulcanized rubber sheet for testing. Also, the unvulcanized rubber composition was extruded using an extruder equipped with a die of a predetermined shape to conform to the shape of the inner layer of the sidewall, and an inner layer of the sidewall with the inorganic fiber material oriented in the alignment direction was obtained. Then, the inner layer of the sidewall was bonded together with other tire members on a tire molding machine so that the inorganic fiber material was oriented in the tire circumferential direction to form an unvulcanized tire, and the tire (size: 205 / 65R15) was manufactured by press-vulcanizing at 170 °C for 12 minutes.

[0090] <Anisotropy test> From the above vulcanized rubber sheet, a dumbbell of JIS No. 3 shape was punched in the alignment direction (the roll rotation direction when manufacturing the unvulcanized rubber sheet before vulcanization), and the tensile stress (M100a) at 100% elongation in the alignment direction was measured under the condition of a tensile speed of 500 mm / min according to JIS K 6251:2017. Similarly, a dumbbell of JIS No. 3 shape was punched in the anti-alignment direction (the direction perpendicular to the roll rotation direction when manufacturing the unvulcanized rubber sheet before vulcanization), and the tensile stress (M100b) at 100% elongation in the anti-alignment direction was measured under the condition of a tensile speed of 500 mm / min according to JIS K 6251:2017. Then, the calculated modulus ratio (M100a / M100b) was described in Table 1 and Table 2.

[0091] <Tensile test> Using a No. 3 dumbbell-shaped test piece made of a vulcanized rubber composition, in accordance with JIS K 6251:2017, the elongation at break EB (%) and the tensile strength at break TB (MPa) of the vulcanized rubber sheet were measured. From the obtained values, the fracture strength was determined by the following formula and expressed as an index when the reference comparative example (Comparative Example 1 in Table 1, Comparative Example 3 in Table 2. The same applies hereinafter) was set to 100 (fracture strength index). The larger the index, the better the fracture strength. Fracture strength = EB × TB / 2

[0092] <Evaluation of Handling Stability and Ride Comfort> The prototype tire was mounted on a standard rim (size = 16 × 6.5J), and this tire was filled with air to an internal pressure of 210 kPa. This tire was mounted on an automobile with a displacement of 2000 cc. This automobile was driven on a test course with an asphalt road surface, and a test driver subjectively evaluated the ride comfort and the stability of control during steering (handling stability). The evaluation was conducted on a scale of 0 to 10, and a relative evaluation was made with the reference comparative example set at 6.0 points. The higher the score, the better the handling stability and ride comfort.

[0093]

Table 1

[0094]

Table 2

[0095] From the results of Table 1 and Table 2, it can be seen that the rubber composition of the present disclosure containing an inorganic fiber material and a coupling agent can highly achieve both fracture strength and anisotropy. Also, it can be seen that the tire of the present disclosure provided with a tire internal member made of the rubber composition has an improved balance between ride comfort and handling stability.

Claims

1. A tire internal member composed of a rubber composition containing a rubber component, an inorganic fiber material, carbon black, and a coupling agent, wherein the inorganic fiber material is one or more inorganic fiber materials selected from the group consisting of magnesium sulfate fiber, calcium silicate fiber, aluminum borate fiber, and glass fiber, the inorganic fiber material is contained in an amount of 1 to 50 parts by mass based on 100 parts by mass of the rubber component, and the content of carbon black based on 100 parts by mass of the rubber component is 30 parts by mass or more. A tire internal member.

2. The tire internal member according to claim 1, wherein the ratio (M100a / M100b) of the 100% modulus M100a in the alignment direction to the 100% modulus M100b in the anti-alignment direction is 1.10 or more.

3. The tire internal member according to claim 1 or 2, further containing a plasticizer.

4. The tire internal member according to any one of claims 1 to 3, wherein the rubber component contains an isoprene-based rubber.

5. The tire internal member according to any one of claims 1 to 4, wherein the coupling agent is a silane coupling agent.

6. The tire internal member according to any one of claims 1 to 5, wherein the coupling agent is contained in an amount of 1 to 40 parts by mass based on 100 parts by mass of the rubber component.

7. The tire internal member according to any one of claims 1 to 6, wherein the coupling agent is a silane coupling agent having a sulfide group.

8. Furthermore, the tire internal member according to any one of claims 1 to 7, containing carbon black having a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 180 m 2 / g or less.

9. The tire internal member according to any one of claims 1 to 8, wherein the inorganic fiber material is one or more inorganic fiber materials selected from the group consisting of magnesium sulfate fiber, calcium silicate fiber, and aluminum borate fiber.

10. A tire including the tire internal member according to any one of claims 1 to 9.

11. The tire according to claim 10, wherein the tire is a passenger car tire.

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