Tire

Abstract

To provide a tire, which is further improved in abrasion resistance and grip performance in a later term.SOLUTION: A tire comprises a tread part. Grooves whose widths are 2 mm or less and whose depths are 20 mm or less having opening parts and groove bottom parts facing the surface of the tread part are formed on the land part of the surface of the tread part. The opening parts cross the groove bottom parts, when the surface of the tread part is viewed from top. A ratio X of areas of crossing parts between the opening parts and the groove bottom parts to areas of the opening parts when the surface of the tread part is viewed from top is 95% or less. The tread part includes rubber ingredients and carbon black and is formed of rubber compositions in which contents (mass parts) Y of carbon black are 20 mass parts or more with respect to 100 mass parts of rubber ingredients, where X and Y satisfy a relational expression of X / Y<4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] In recent years, there has been an increasing demand for improving the performance of tires. In particular, further improvement in wear resistance and grip performance in the latter stage of wear (late-stage grip performance) is desired, and various techniques have been proposed therefor (for example, Patent Document 1), but the current situation is that they are still not sufficient.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the above problems, an object of the present invention is to further improve wear resistance and late-stage grip performance in a tire.

Means for Solving the Problems

[0005] The present invention is a tire including a tread portion, wherein a groove having a width of 2 mm or less and a depth of 20 mm or less, having an opening facing the surface of the tread portion and a groove bottom, is formed in a land portion on the surface of the tread portion, the opening and the groove bottom intersect when the surface of the tread portion is viewed in plan, a ratio X of an area of an intersection portion of the opening and the groove bottom to an area of the opening when the surface of the tread portion is viewed in plan is 95% or less, The tread portion is formed of a rubber composition containing a rubber component and carbon black, and the content (parts by mass) Y of the carbon black is 20 parts by mass or more with respect to 100 parts by mass of the rubber component. Furthermore, it is a tire characterized in that X / Y < 4.

Effect of the Invention

[0006] According to the present invention, further improvement in wear resistance and late grip performance in a tire can be achieved.

Brief Description of the Drawings

[0007]

Figure 1

Mode for Carrying Out the Invention

[0008] [1] Features of the Tire According to the Present Invention First, the features of the tire according to the present invention will be described.

[0009] 1. Outline The tire according to the present invention is a tire having a tread portion. On the land portion of the surface of the tread portion, a groove (hereinafter also referred to as a "sipe") having an opening facing the surface of the tread portion and a groove bottom portion, with a width of 2 mm or less and a depth of 20 mm or less, is formed. In this sipe, the opening and the groove bottom portion intersect when the surface of the tread portion is viewed in plan, and the ratio X of the area of the intersection portion of the opening and the groove bottom portion to the area of the opening when the surface of the tread portion is viewed in plan is 95% or less. Further, the tread portion is formed of a rubber composition containing a rubber component and carbon black, and the content (parts by mass) Y of the carbon black is 20 parts by mass or more with respect to 100 parts by mass of the rubber component. Furthermore, the ratio (X / Y) of X to Y is less than 4.

[0010] By having these features, as will be described later, it is possible to improve the wear resistance of the tire and also to improve the grip performance in the later stage.

[0011] 2. Mechanism of Effect Expression in the Tire According to the Present Invention The mechanism of the above-described effect expression in the tire according to the present invention is considered as follows.

[0012] (1) Shape of the Tread Portion As described above, in the tire according to the present invention, on the land portion of the surface of the tread portion, a sipe having an opening portion facing the surface of the tread portion and a groove bottom portion is formed. And this sipe is formed in a shape in which the opening portion and the groove bottom portion intersect when the surface of the tread portion is viewed in plan, that is, a twisted shape.

[0013] By providing such a twisted-shaped sipe on the surface of the tread portion, it is considered that the wear resistance can be improved. Also, since the rigidity of the tread portion can be ensured even in the later stage of wear, it is considered that the grip performance in the later stage can be improved.

[0014] At this time, if a sufficient twisted shape is not formed, that is, if the area of the intersection portion (overlap portion) of the opening portion and the groove bottom portion is not sufficiently small, the wear of the tire cannot be appropriately controlled, so the grip performance in the later stage cannot be sufficiently improved. For this reason, in the present invention, the ratio X (= B / A) of the area B (mm 2 ) of the intersection portion of the opening portion and the groove bottom portion to the area A (mm 2 ) of the opening portion when the surface of the tread portion is viewed in plan is set to 95% or less. It is more preferably 90% or less, further preferably 80% or less, further preferably 70% or less, further preferably 60% or less, and further preferably 50% or less. As the lower limit, for example, it is preferably 1% or more, more preferably 5% or more, further preferably 10% or more, further preferably 20% or more, further preferably 30% or more, and further preferably 40% or more.

[0015] (2) The rubber composition forming the tread portion In the present invention, the tread portion is formed of a rubber composition containing a rubber component and carbon black, and the content (parts by mass) Y of carbon black is 20 parts by mass or more with respect to 100 parts by mass of the rubber component.

[0016] By containing 20 parts by mass or more of carbon black as a reinforcing agent in the rubber composition with respect to 100 parts by mass of the rubber component, the wear of the tire can be appropriately controlled, and the rigidity of the tread portion can be ensured even in the late stage of wear. Therefore, it is considered that the wear resistance can be improved and the grip performance in the late stage can be improved.

[0017] In the present invention, the content of carbon black with respect to 100 parts by mass of the above-described rubber component is more preferably 30 parts by mass or more, further preferably 40 parts by mass or more, and still further preferably 50 parts by mass or more. As the upper limit, for example, it is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, still further preferably 80 parts by mass or less, and still further preferably 70 parts by mass or less.

[0018] (3) X / Y And in the present invention, further, the ratio (X / Y) of the above-described X to Y is controlled to be less than 4. Thereby, the effect in the above-described twist cycle and the effect in the rubber composition cooperate with each other to more appropriately control the wear of the tire, improve the wear resistance, and improve the grip performance in the late stage. It is considered possible. It is more preferably 3.5 or less, further preferably 3.0 or less, and still further preferably 2.5 or less. As the lower limit, it is preferably 0.3 or more, more preferably 0.6 or more, still further preferably 0.9 or more, and still further preferably 1.2 or more.

[0019] [2] More preferable embodiments of the tire according to the present invention The tire according to the present invention can obtain a greater effect by adopting the following aspects.

[0020] 1. Lamination of the tread portion In the tire according to the present invention, the preferred thickness of the tread portion is 10 mm or more and 20 mm or less, more preferably 12 mm or more and 18 mm or less, and even more preferably 14 mm or more and 16 mm or less.

[0021] Note that the tread portion may be formed of only one layer of cap rubber layer, but a base rubber layer may be provided inside the cap rubber layer to form two layers, or three layers, or four or more layers.

[0022] In this case, the thickness of the cap rubber layer in the entire tread portion is preferably 10% or more, more preferably 30% or more, even more preferably 50% or more, and even more preferably 70% or more. Thereby, while maintaining the wear resistance, sufficient friction can be generated between the tread portion surface and the road surface even in the later stage of wear, so it is considered that the grip performance in the later stage can be further improved.

[0023] The thickness of the tread portion described above refers to the thickness of the tread portion on the tire equator plane in the tire radial cross-section. When the tread portion is formed of a single rubber composition, it is the thickness of the rubber composition. When it is formed of a laminated structure of a plurality of rubber compositions described later, it refers to the total thickness of these layers.

[0024] Note that in the present invention, the tread portion is a member in the region forming the ground contact surface of the tire, but refers to the portion outside the tire in the radial direction from members including fiber materials such as carcass, belt layer, and belt reinforcing layer. Also, the thickness of the tread portion described above can be measured by making the bead portion conform to the normal rim width in the cross-section obtained by cutting the tire in the radial direction.

[0025] Note that the "regular rim" is the rim defined for each tire in a standard system that includes the standards on which the tire is based. For example, in the case of JATMA (Japan Automobile Tire Association), it refers to the standard rim in the applicable sizes described in the "JATMA YEAR BOOK"; in the case of ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" described in the "STANDARDS MANUAL"; and in the case of TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" described in the "YEAR BOOK". Refer to JATMA, ETRTO, and TRA in that order, and follow the relevant standards if there are applicable sizes during the reference. In the case of a tire not defined by the standards, it refers to the rim that can be assembled with the tire and can hold the internal pressure, that is, among the rims that do not cause air leakage between the rim / tire, the one with the smallest rim diameter and then the narrowest rim width.

[0026] 2. Aspect ratio The aspect ratio is the ratio of the cross-sectional height to the cross-sectional width of the tire. It is considered that the smaller this ratio (lower aspect ratio), the better the grip performance. On the other hand, if the aspect ratio becomes too low, there is a risk of deterioration in the riding comfort performance.

[0027] Considering these points, in the tire according to the present invention, the aspect ratio is preferably 30% or more and 60% or less, and more preferably 40% or more and 50% or less.

[0028] Note that the above aspect ratio (%) can be obtained by the following formula using the cross-sectional height Ht (mm), cross-sectional width Wt (mm), outer diameter Dt (mm) of the tire, and rim diameter R (mm) of the tire when the internal pressure is 250 kPa. Aspect ratio (%) = (Ht / Wt) × 100 (%) Ht = (Dt - R) / 2

[0029] 3. Styrene content in SBR In the rubber composition constituting the tread portion of the tire according to the present invention, when styrene-butadiene rubber (SBR) with a small amount of styrene (mass ratio) is used as the rubber component, it is possible to form minute styrene domains in the rubber matrix. Therefore, it is considered that further improvement in abrasion resistance and further improvement in grip performance in the later stage can be achieved.

[0030] Specifically, SBR having a styrene content of 25% by mass or less is preferable, more preferably 20% by mass or less, and even more preferably 15% by mass or less. On the other hand, as the lower limit, it is preferably 4% by mass or more, more preferably 5% by mass or more, and even more preferably 6% by mass or more.

[0031] Note that the SBR with a styrene content of 25% by mass or less described above means that when a styrene-containing polymer (SBR) is contained alone in the rubber component, the styrene content is 25% by mass or less. When a plurality of styrene-containing polymers (SBR) are contained in the rubber component, it means that the styrene content obtained by the sum of the product of the styrene content (mass%) in each polymer and the compounding amount (parts by mass) with respect to 100 parts by mass of the rubber component of that polymer is 25% by mass or less.

[0032] More specifically, when SBR1 (X1 parts by mass) having a styrene content of S1% by mass and SBR2 (X2 parts by mass) having a styrene content of S2% by mass are contained in 100 parts by mass of the rubber component, it indicates that the styrene content calculated from the formula of {(S1×X1)+(S2×X2)} / (X1+X2) is 25% by mass or less.

[0033] Also, in the vulcanized rubber composition, it is also possible to calculate by determining the styrene content contained in the rubber component after acetone extraction using solid nuclear magnetic resonance (solid NMR) or Fourier transform infrared spectrophotometer (FTIR).

[0034] 4. Inclusion of resin component In the present invention, it is preferable that the rubber composition forming the tread portion contains a resin component.

[0035] When a resin component is contained in the rubber composition, it is considered that the grip property against the road surface can be maintained by the adhesiveness of the resin component, and the late-stage grip performance can be further improved.

[0036] Preferred resin components include rosin resins, styrene resins, coumarone resins, terpene resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc. described later. Among these, terpene resins are more preferred.

[0037] [3] Embodiment Hereinafter, the present invention will be specifically described based on the embodiment.

[0038] 1. Sipe FIG. 1 is a (a) schematic perspective view and (b) schematic plan view for explaining a groove provided in a tire according to the present invention. In FIG. 1, a sipe provided in one land portion in the tread portion is shown, 1 is the land portion, 2 is the opening portion, and 3 is the groove bottom portion. Further, S is the intersection of the opening portion and the groove bottom portion.

[0039] As shown in FIG. 1(a), the sipe is provided with a twist from the opening portion 2 to the groove bottom portion 3. When viewed in plan, as shown in FIG. 1(b), an intersection S where the opening portion 1 and the groove bottom portion 2 overlap is formed.

[0040] And, as described above, by setting the ratio of the area of the intersection S to the area of the opening portion 2 to 95% or less, the late-stage grip performance can be sufficiently improved.

[0041] 2. Rubber composition In the present embodiment, the rubber composition constituting the tread portion can be obtained by kneading various compounding materials such as a rubber component, a reinforcing material, an antioxidant, an oil, a resin material, and an antioxidant.

[0042] (1) Compounding materials (a) Rubber component The rubber component is not particularly limited, and diene rubbers such as isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), and nitrile rubber (NBR), butyl rubbers such as butyl rubber (IIR), and thermoplastic elastomers such as styrene-butadiene-styrene block copolymer (SBS) and styrene-butadiene block copolymer (SB), etc., rubbers (polymers) generally used in the manufacture of tires can be used.

[0043] In the present embodiment, among these, from the point of including styrene in the rubber component, any one of styrene-based polymers such as SBR, SBS, and SB is included, and it is preferable to include SBR. Further, these styrene-based polymers and other rubber components may be used in combination. For example, the combined use of SBR and BR, or the combined use of SBR, BR, and isoprene rubber is preferable.

[0044] (i) SBR The weight average molecular weight of SBR is, for example, more than 100,000 and less than 2,000,000. The styrene content of SBR is preferably, for example, more than 5% by mass, more preferably more than 10% by mass, and even more preferably more than 15% by mass. On the other hand, it is preferably less than 40% by mass, more preferably less than 35% by mass, and even more preferably less than 30% by mass. The vinyl content (amount of 1,2-bonded butadiene units) of SBR is preferably, for example, more than 5% by mass, more preferably more than 10% by mass, and even more preferably more than 15% by mass. On the other hand, it is preferably less than 70% by mass, more preferably less than 40% by mass, and even more preferably less than 30% by mass. Incidentally, the structure identification (measurement of styrene content and vinyl content) of SBR can be performed, for example, using an apparatus of the JNM-ECA series manufactured by JEOL Ltd.

[0045] The SBR is not particularly limited, and for example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR), etc. can be used. The SBR may be either unmodified SBR or modified SBR. Further, hydrogenated SBR in which the butadiene part in the SBR is hydrogenated may be used, and the hydrogenated SBR may be obtained by post-hydrogenation treatment of the BR part in the SBR, or styrene, ethylene, and butadiene may be copolymerized to obtain a similar structure.

[0046] As the modified SBR, it is preferably an SBR having a functional group that interacts with a filler such as silica. For example, a terminal-modified SBR (terminal-modified SBR having the above functional group at the terminal) in which at least one terminal of the SBR is modified with a compound (modifying agent) having the above functional group, a main-chain modified SBR having the above functional group in the main chain, a main-chain terminal modified SBR having the above functional group in the main chain and at the terminal (for example, a main-chain terminal modified SBR having the above functional group in the main chain and at least one terminal modified with the above modifying agent), a terminal-modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or an epoxy group introduced therein, etc. can be mentioned.

[0047] Examples of the above 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, an epoxy group, etc. Note that these functional groups may have substituents.

[0048] Further, as the modified SBR, for example, an SBR modified with a compound (modifying agent) represented by the following formula can be used.

[0049]

Chemical formula

[0050] In the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH) or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R 4 and R 5 may combine to form a ring structure together with a nitrogen atom. n represents an integer.

[0051] As the modified SBR modified with the compound (modifying agent) represented by the above formula, SBR obtained by modifying the polymerization terminal (active terminal) of solution-polymerized styrene-butadiene rubber (S-SBR) with the compound represented by the above formula (modified SBR described in JP-A-2010-111753, etc.) can be used.

[0052] R 1 , R 2 and R 3 is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). R 4 and R 5 are preferably an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Further, when R 4 and R 5 combine to form a ring structure together with a nitrogen atom, it is preferably a 4- to 8-membered ring. The alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0053] Specific examples of the above-mentioned modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. These may be used alone or in combination of two or more kinds.

[0054] In addition, as the modified SBR, modified SBR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine, 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide and other sulfide group-containing silane compounds; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-t-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; In addition, N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone and the like can be mentioned. The modification with the above compound (modifying agent) can be carried out by a known method.;

[0055] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., ENEOS MATERIALS Co., Ltd., Asahi Kasei Co., Ltd., Zeon Corporation, etc. can be used. The SBR may be used alone or in combination of two or more kinds.

[0056] The content of SBR in 100 parts by mass of the rubber component is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 35 parts by mass or more. As the upper limit, for example, it is preferably 55 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 45 parts by mass or less.

[0057] (b) Isoprene rubber Examples of the isoprene rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, etc. NR is preferred in terms of excellent strength.

[0058] As the NR, for example, those commonly used in the tire industry such as SVR-L, SIR20, RSS#3, TSR20, etc. can be used. As the IR, there is no particular limitation, and for example, those commonly used in the tire industry such as IR2200 manufactured by Nippon Zeon Co., Ltd. can be used. As the modified NR, deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. can be used. As the modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. can be used. As the modified IR, epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. can be used. These may be used alone or in combination of two or more.

[0059] The content of isoprene rubber in 100 parts by mass of the rubber component is preferably 35 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 45 parts by mass or more. As the upper limit, for example, it is preferably 65 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less.

[0060] (C) BR The weight average molecular weight of BR is, for example, more than 100,000 and less than 2,000,000. The vinyl content of BR is, for example, more than 1% by mass and less than 30% by mass. The cis content of BR is, for example, more than 1% by mass and 98% by mass or less. The trans content of BR is, for example, more than 1% by mass and less than 60% by mass. The cis content can be measured by infrared absorption spectroscopy.

[0061] BR is not particularly limited, and BR with a high cis content (cis content of 90% or more), BR with a low cis content, BR containing syndiotactic polybutadiene crystals, etc. can be used. BR can be either unmodified BR or modified BR. As the modified BR, for example, BR modified with a compound (modifying agent) represented by the following formula can be used.

[0062] [Chemical formula]

[0063] In the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH) or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R 4 and R 5 may combine to form a ring structure together with a nitrogen atom. n represents an integer.

[0064] Examples of the modified BR modified with the compound (modifying agent) represented by the above formula include BR in which the polymerization terminal (active terminal) is modified with the compound represented by the above formula.

[0065] R 1 , R 2 and R 3 are preferably alkoxy groups (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). R 4 and R 5 are preferably alkyl groups (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Further, when R 4 and R 5 combine to form a ring structure together with a nitrogen atom, a 4- to 8-membered ring is preferred. The alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0066] Specific examples of the above-mentioned modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, and the like. These may be used alone or in combination of two or more.

[0067] In addition, as the modified BR, modified BR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine, 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide and other sulfide group-containing silane compounds; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-t-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; In addition, N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone and the like can be mentioned. In addition, the modification with the above compound (modifying agent) can be carried out by a known method. These modified BRs may be used alone or in combination of two or more kinds.;

[0068] As BR, for example, products of Ube Industries, Ltd., ENEOS MATERIALS Co., Ltd., Asahi Kasei Corporation, Nippon Zeon Co., Ltd. and the like can be used.

[0069] The content of BR in 100 parts by mass of the rubber component is preferably 5 parts by mass or more, and more preferably 8 parts by mass or more. On the other hand, it is preferably 15 parts by mass or less, and more preferably 12 parts by mass or less.

[0070] (ii) Other rubber components The rubber composition may contain, as other rubber components, rubber (polymer) generally used in the production of tires such as nitrile rubber (NBR), if necessary.

[0071] (b) Compound materials other than rubber components (i) Filler In the present embodiment, the rubber composition contains carbon black as a filler, but as other fillers, for example, silica, graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. may be contained. When using silica, it is preferably used in combination with a silane coupling agent.

[0072] The total blending amount of the filler is preferably 90 parts by mass or more, more preferably 110 parts by mass or more, based on 100 parts by mass of the rubber component. On the other hand, from the viewpoint of dispersibility in the rubber composition, it is preferably 150 parts by mass or less, more preferably 130 parts by mass or less.

[0073] (i) Carbon black Carbon black is used from the viewpoint of improving abrasion resistance and late grip performance by improving the crack growth resistance, durability, ultraviolet degradation resistance, etc. of the tire.

[0074] The nitrogen adsorption specific surface area (N2SA) of carbon black is, for example, 30 m 2 / g or more, more preferably 50 m 2 / g or more, and even more preferably 60 m 2 / g or more, from the viewpoint of the reinforcing property to the rubber. On the other hand, from the viewpoint of heat generation, it is preferably 250 m 2 / g or less, more preferably 150 m 2 / g or less, and even more preferably 120 m 2 / g or less. The nitrogen adsorption specific surface area of carbon black is measured according to ASTM D4820-93.

[0075] The dibutyl phthalate (DBP) absorption of carbon black is preferably, for example, 50 ml / 100 g or more, more preferably 100 ml / 100 g or more, from the viewpoint of the rigidity of the rubber. On the other hand, from the viewpoint of the followability of the rubber to deformation, it is preferably 250 ml / 100 g or less, more preferably 150 ml / 100 g or less. The DBP absorption of carbon black is measured according to ASTM D2414-93.

[0076] The carbon black is not particularly limited, and examples thereof include furnace black (furnace carbon black) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal black (thermal carbon black) such as FT and MT; channel black (channel carbon black) such as EPC, MPC, and CC. These may be used alone or in combination of two or more.

[0077] In addition to carbon black made from mineral oil or the like, biomass-derived carbon black obtained by burning lignin or the like, and recycled carbon black obtained by pyrolyzing and purifying rubber products containing carbon black such as tires may be appropriately used in an equal amount substitution with these.

[0078] Specific carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. As commercially available products, for example, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nippon Carbon Co., Ltd., Columbian Carbon Company, etc. can be used, and these may be used alone or in combination of two or more.

[0079] As described above, in the present invention, the content of carbon black with respect to 100 parts by mass of the rubber component is 20 parts by mass or more, more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, and still more preferably 50 parts by mass or more. Further, as the upper limit, for example, it is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, still more preferably 80 parts by mass or less, and still more preferably 70 parts by mass or less.

[0080] (ii) Silica The rubber composition may contain silica as necessary. Since the water of hydration and surface functional groups contained in silica can capture ozone, the ozone resistance can be improved, and the durability of the tire can be improved.

[0081] As the silica, since the processability deteriorates if the average primary particle diameter is too small, it is preferable to use silica having an average primary particle diameter of more than 8 nm. More preferably 9 nm or more, still more preferably 10 nm or more. On the other hand, from the viewpoints of ensuring the reinforcement of the rubber and ensuring the handling stability performance on a wet road surface during driving, it is preferably 25 nm or less, more preferably 20 nm or less, and still more preferably 17 nm or less.

[0082] The average primary particle diameter of silica means the average value of the values measured by observing the minimum particle unit of silica constituting the aggregated structure as a circle and taking the absolute maximum length of the minimum particle as the diameter of the circle. It can be observed with a transmission or scanning electron microscope, and more than 400 primary particles of silica observed in the visual field are measured, and the average value can be obtained therefrom.

[0083] The BET specific surface area of silica is more than 100 m 2 / g from the viewpoint of obtaining good durability performance, preferably more than 130 m 2 / g. On the other hand, it is preferably less than 250 m 2 / g, more preferably less than 200 m 2It is more preferable that it is less than / g. The above-mentioned BET specific surface area is the value of N2SA measured by the BET method in accordance with ASTM D3037-93.

[0084] Examples of the silica include dry-process silica (anhydrous silica), wet-process silica (hydrous silica), colloidal silica, etc. Among them, wet-process silica containing water of hydration and a large amount of silanol groups and capable of effectively capturing ozone is preferable. Further, silica using hydrated glass or the like as a raw material, silica using biomass materials such as rice husks as a raw material, etc. may also be used.

[0085] As the silica, products of Evonik Industries AG, Rhodia, Tosoh Silica Corporation, Solvay Japan Ltd., Tokuyama Corporation, etc. can be used.

[0086] The content of silica with respect to 100 parts by mass of the rubber component is preferably 70 parts by mass or more, more preferably 80 parts by mass or more, and still more preferably 90 parts by mass or more with respect to 100 parts by mass of the rubber component. As the upper limit, from the viewpoint of dispersibility in the rubber composition, it is preferably 130 parts by mass or less, more preferably 120 parts by mass or less, and still more preferably 110 parts by mass or less.

[0087] (iii) Silane coupling agent When using silica, in order to enhance the dispersibility of silica and improve mechanical properties and moldability by reaction with silica, it is preferable to use a silane coupling agent in combination.

[0088] The silane coupling agent is not particularly limited. 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, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, etc. sulfide-based, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, mercapto-based such as NXT and NXT-Z manufactured by Momentive, vinyl-based such as vinyltriethoxysilane and vinyltrimethoxysilane, amino-based such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane, glycidoxy-based such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, nitro-based such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, chloro-based such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane, etc. can be mentioned. Among these, a silane coupling agent having a thiocarbonyl group such as NXT mentioned above is preferred. These may be used alone or in combination of two or more.

[0089] As the silane coupling agent, for example, products of Evonik Industries, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Toray Dow Corning Co., Ltd. and the like can be used.

[0090] The content of the silane coupling agent is preferably more than, for example, 3 parts by mass, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more with respect to 100 parts by mass of silica. As the upper limit, it is preferably less than, for example, 15 parts by mass, more preferably 12 parts by mass or less, and even more preferably 10 parts by mass or less.

[0091] (iv) Other fillers In addition to the above-mentioned carbon black and silica, the rubber composition may further contain fillers generally used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, magnesium sulfate and the like. The content of these is, for example, more than 0.1 part by mass and less than 150 parts by mass with respect to 100 parts by mass of the rubber component.

[0092] (b) Plasticizer component In consideration of the proper dispersion of the powder material during kneading, it is preferable to use a plasticizer component as necessary. Here, the plasticizer component refers to those that plasticize the rubber composition, such as process oil, extender oil for rubber components, liquid rubber, resin components and the like.

[0093] At this time, the content of the plasticizer component with respect to 100 parts by mass of the rubber component is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more. As the upper limit, it is preferably, for example, 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.

[0094] Note that the content of the plasticizer component includes the amount of oil contained in rubber (oil-extended rubber) and the like.

[0095] (i) Oil Examples of the oil include mineral oil, synthetic oil, vegetable oil, animal oil, or a mixture thereof.

[0096] Examples of the mineral oil include paraffinic, aromatic, and naphthenic oils. For example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Orisoy Co., H&R Co., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kogyo Co., Ltd., etc. can be used. These may be used alone or in combination of two or more.

[0097] Also, from the perspective of life cycle assessment, lubricating oil used in a mixer or engine of a rubber mixer, waste cooking oil after use in a cooking shop, etc. may be appropriately refined and used as these oils.

[0098] Examples of the vegetable oil include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood rosin, etc.

[0099] Furthermore, examples of the vegetable oil also include refined oil (such as salad oil) obtained by refining each of the above oils, transesterified oil obtained by transesterification, hydrogenated hardened oil, thermally polymerized oil obtained by thermal polymerization, oxidation polymerized oil obtained by oxidation, waste cooking oil recovered from those used as edible oil, etc. Note that the vegetable oil may be liquid or solid at normal temperature (25°C). These may be used alone or in combination of two or more.

[0100] As the vegetable oil, acylglycerol is preferred, and triacylglycerol is more preferred. Note that acylglycerol refers to a compound in which the hydroxy group of glycerin and a carboxylic acid are ester-bonded. The acylglycerol is not particularly limited, and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Further, the acylglycerol may be a monomer, a dimer, or a multimer of trimer or higher. Note that acylglycerols of dimer or higher can be obtained by thermal polymerization, oxidative polymerization, or the like. Also, the acylglycerol may be liquid or solid at room temperature (25°C).

[0101] As a method for confirming whether acylglycerol is contained in the rubber composition, it is not particularly limited, but 1 it can be confirmed by 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours. After removing the rubber composition, at room temperature 1 1H-NMR is measured. When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm are observed. Since these signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group, the presence of acylglycerol can be confirmed. Here, "around" refers to a range of ±0.10 ppm.

[0102] Note that the carboxylic acid is not particularly limited, and may be an unsaturated fatty acid or a saturated fatty acid. Examples of the unsaturated fatty acid include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid.

[0103] As the vegetable oil, for example, those commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0104] (ii) Liquid rubber Liquid rubber is a polymer in a liquid state at normal temperature (25 °C) and is a rubber component that can be extracted from the vulcanized tire by acetone extraction. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and hydrogenated products thereof.

[0105] A farnesene-based polymer is a polymer obtained by polymerizing farnesene and has a structural unit based on farnesene. Farnesene has isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene).

[0106] The farnesene-based polymer may be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

[0107] Examples of liquid diene-based polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), and the like.

[0108] The liquid diene-based polymer has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of, for example, more than 1.0×10 3 super and less than 2.0×10 5 Here, the Mw of the liquid diene-based polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0109] As the liquid rubber, for example, products of Kuraray Co., Ltd., KRAIBURG Co., Ltd., etc. can be used.

[0110] (iii) Resin component The resin component also functions as an adhesiveness-imparting component and may be solid or liquid at normal temperature. Specific resin components include, for example, rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc. Two or more of them may be used in combination. In addition, these resin components may be provided with a modifying group capable of reacting with silica or the like as necessary.

[0111] The rosin-based resin is a resin mainly composed of rosin acid obtained by processing pine resin. This rosin-based resin (rosins) can be classified according to the presence or absence of modification, and can be classified into unmodified rosin (unmodified rosin) and rosin modified products (rosin derivatives). Examples of unmodified rosin include tall rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Rosin modified products are modified products of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid-modified rosins, unsaturated carboxylic acid-modified rosin esters, amide compounds of rosin, amine salts of rosin, etc.

[0112] The styrene-based resin is a polymer using a styrene-based monomer as a constituent monomer, and examples include polymers polymerized with a styrene-based monomer as a main component (50% by mass or more). Specifically, homopolymers obtained by polymerizing each styrene-based monomer (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.) alone, copolymers obtained by copolymerizing two or more styrene-based monomers, and copolymers of a styrene-based monomer and other monomers copolymerizable therewith are also included.

[0113] Examples of the other monomer include acrylonitriles such as acrylonitrile and methacrylonitrile, acrylates, unsaturated carboxylic acids such as methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene, butadiene and isoprene, olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or acid anhydrides thereof; and the like.

[0114] Among coumarone resins, coumarone-indene resins are preferred. A coumarone-indene resin is a resin containing coumarone and indene as monomer components constituting the resin skeleton (main chain). Examples of monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methyl indene, vinyltoluene and the like.

[0115] The hydroxyl value (OH value) of the coumarone-indene resin is, for example, more than 15 mgKOH / g and less than 150 mgKOH / g. The OH value represents the amount of potassium hydroxide in milligrams required to neutralize acetic acid bonded to hydroxyl groups when 1 g of the resin is acetylated, and is a value measured by the potentiometric titration method (JIS K 0070:1992).

[0116] The softening point of the coumarone-indene resin is, for example, more than 30°C and less than 160°C. The softening point is the temperature at which the ball drops when measured with a ring and ball softening point measuring device according to the softening point specified in JIS K 6220-1:2001.

[0117] Examples of terpene resins include polyterpene, terpene phenol, aromatic modified terpene resin and the like. Polyterpene is a resin obtained by polymerizing terpene compounds and hydrogenated products thereof. Terpene compounds are hydrocarbons represented by the composition of (C5H8) n and oxygen-containing derivatives thereof, and include monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H32 ) It is a compound having a terpene as a basic skeleton and classified into, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, allo-ocimene, ocimene, α-farnesene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc.

[0118] Examples of polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc. using the above-mentioned terpene compounds as raw materials, and hydrogenated terpene resins obtained by hydrogenating the terpene resins. Examples of terpene phenols include resins obtained by copolymerizing the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating the resins. Specifically, resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds and formalin are included. Examples of phenolic compounds include phenol, bisphenol A, cresol, xylenol, etc. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating the resins. The aromatic compound is not particularly limited as long as it has an aromatic ring, and examples include phenolic compounds such as phenol, alkylphenol, alkoxyphenol, phenol containing an unsaturated hydrocarbon group; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, naphthol containing an unsaturated hydrocarbon group; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, styrene containing an unsaturated hydrocarbon group; coumarone, indene, etc.

[0119] "C5 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, isoprene, etc. As the C5-based petroleum resin, dicyclopentadiene resin (DCPD resin) is preferably used.

[0120] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, which may be hydrogenated or modified. Examples of the C9 fraction include petroleum fractions equivalent to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, and methylindene. As specific examples, for instance, coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl resins are preferably used. Among aromatic vinyl resins, α-methylstyrene (AMS resin) or a homopolymer of styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, because they are economical, easy to process, and excellent in heat generation properties. As aromatic vinyl resins, those commercially available from companies such as Kreton and Eastman Chemical can be used.

[0121] "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, which may be hydrogenated or modified. Examples of the C5 fraction and the C9 fraction include the above-mentioned petroleum fractions. As C5C9 resins, those commercially available from companies such as Tosoh Corporation and LUHUA can be used.

[0122] The acrylic resin is not particularly limited, and for example, a solventless acrylic resin can be used.

[0123] The solventless acrylic resin is a (meth)acrylic resin (polymer) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (the methods described in U.S. Patent No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Patent No. 5,010,166, and TREND 2000, No. 3, p42-45 of Toagosei Research Annual Report, etc.) without using a polymerization initiator, a chain transfer agent, an organic solvent, etc. as auxiliary raw materials as much as possible. In the present invention, "(meth)acrylic" means methacrylic and acrylic.

[0124] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (such as alkyl esters, aryl esters, and aralkyl esters), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0125] In addition, as the monomer components constituting the acrylic resin, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or (meth)acrylic acid derivatives.

[0126] The acrylic resin may be a resin composed only of the (meth)acrylic component or a resin having components other than the (meth)acrylic component as constituent elements. Further, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0127] Examples of the resin component include products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Clayton, Nippon Paint Co., Ltd., Nippon Catalyst Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., Tago Chemical Industry Co., Ltd., etc.

[0128] (c) Lubricant (stearic acid) The rubber composition may contain a lubricant. As the lubricant, lubricants based on fatty acid derivatives such as stearic acid can be preferably used. As stearic acid, conventionally known ones can be used. Specifically, for example, products of NOF Corporation, Kao Corporation, Fuji Film Wako Pure Chemical Corporation, Chiba Fatty Acids Co., Ltd., etc. can be used. In addition, Struktol WB16 manufactured by Struktol can also be used.

[0129] The content of stearic acid is preferably more than 0.5 part by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0130] (B) Antioxidant The rubber composition may contain an antioxidant. The content of the antioxidant is, for example, more than 1 part by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0131] Examples of the antioxidant include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4′-bis(α,α′-dimethylbenzyl)diphenylamine; p-phenylenediamine-based antioxidants such as N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, and N,N′-di-2-naphthyl-p-phenylenediamine; quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; bis, tris, polyphenol-based antioxidants such as tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane, etc. These may be used alone or in combination of two or more.

[0132] As specific antioxidants, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Industry Co., Ltd., Flexsys Co., etc. can be used.

[0133] (E) Zinc Oxide The rubber composition may contain zinc oxide. The content of zinc oxide is, for example, more than 0.5 part by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component. As zinc oxide, conventionally known ones can be used, for example, products of Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusuitech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0134] (F) Wax The rubber composition may contain wax. The content of the wax is preferably, for example, 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, and still more preferably 1.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0135] The wax is not particularly limited, and examples include petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as vegetable waxes and animal waxes; and synthetic waxes such as polymers of ethylene, propylene, and the like. These may be used alone or in combination of two or more.

[0136] In addition, as the wax, for example, products of Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Seiko Chemical Co., Ltd., etc. can be used.

[0137] (d) Crosslinking agent and vulcanization accelerator The rubber composition preferably contains a crosslinking agent such as sulfur. The content of the crosslinking agent is, for example, more than 0.1 part by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component. The sulfur content is the pure sulfur content, and when insoluble sulfur is used, it is the content excluding the oil component.

[0138] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc., which are generally used in the rubber industry. These may be used alone or in combination of two or more.

[0139] In addition, as the sulfur, for example, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexsys, Nippon Kankyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0140] Crosslinking agents other than sulfur may be used. Specifically, for example, Tackiol V200 manufactured by Tago Chemical Industry Co., Ltd., DURALINK HTS (sodium 1,6 - hexamethylene - dithiolsulfate dihydrate) manufactured by Flexsys, KA9188 (1,6 - bis(N,N’ - dibenzylthiocarbamoyldithio)hexane: hybrid crosslinking agent) manufactured by Lanxess, etc., vulcanizing agents containing sulfur atoms, and organic peroxides such as dicumyl peroxide can be used.

[0141] And the rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, more than 0.3 parts by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0142] Examples of the vulcanization accelerator include thiazole - type vulcanization accelerators such as 2 - mercaptobenzothiazole, di - 2 - benzothiazolyldisulfide, N - cyclohexyl - 2 - benzothiazylsulfenamide; thiuram - type vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), tetrakis(2 - ethylhexyl)thiuram disulfide (TOT - N); sulfenamide - type vulcanization accelerators such as N - cyclohexyl - 2 - benzothiazolesulfenamide, N - t - butyl - 2 - benzothiazolylsulfenamide, N - oxyethylene - 2 - benzothiazolesulfenamide, N - oxyethylene - 2 - benzothiazolesulfenamide, N,N’ - diisopropyl - 2 - benzothiazolesulfenamide; and guanidine - type vulcanization accelerators such as diphenylguanidine, di - ortho - tolylguanidine, ortho - tolylbiguanidine. These may be used alone or in combination of two or more.

[0143] (Etc.) Others In addition to the above - mentioned components, additives generally used in the tire industry, such as organic fillers like cellulose fibers and organic peroxides, may be blended into the rubber composition as needed. The content of these additives is, for example, more than 0.1 parts by mass and less than 50 parts by mass with respect to 100 parts by mass of the rubber component.

[0144] (2) Preparation of Rubber Composition The rubber composition can be prepared by a production method including a base kneading step of kneading a rubber component and a filler such as carbon black by a general method, and a finishing kneading step of kneading the kneaded product obtained in the base kneading step and a crosslinking agent.

[0145] Kneading can be performed using a known (closed-type) kneader such as a Banbury mixer, a kneader, or an open roll.

[0146] The kneading temperature in the base kneading step is, for example, above 50°C and below 200°C, and the kneading time is, for example, above 30 seconds and below 30 minutes. In the base kneading step, in addition to the above components, compounding agents conventionally used in the rubber industry, such as softening agents such as oil, stearic acid, zinc oxide, anti-aging agents, waxes, vulcanization accelerators, etc., may be appropriately added and kneaded as necessary.

[0147] In the finishing kneading step, the kneaded product obtained in the base kneading step and a crosslinking agent are kneaded. The kneading temperature in the finishing kneading step is, for example, above room temperature and below 80°C, and the kneading time is, for example, above 1 minute and below 15 minutes. In the finishing kneading step, in addition to the above components, vulcanization accelerators, zinc oxide, etc. may be appropriately added and kneaded as necessary.

[0148] The rubber composition obtained as described above can then be formed into a tread by extrusion into a predetermined shape.

[0149] 3. Manufacture of Tire The tire according to the present embodiment can be manufactured by a normal method. First, using the rubber composition obtained as described above, it is formed into a predetermined shape to manufacture a tread. Next, it is combined with other rubber members on a tire molding machine to produce an unvulcanized tire.

[0150] Specifically, on a forming drum, an inner liner as a member for ensuring the airtightness of a tire, a carcass as a member for withstanding the load, impact, and inflation pressure received by the tire, a belt member as a member for strongly clamping the carcass to increase the rigidity of the tread, etc. are wound, both ends of the carcass are fixed to both side edges, and a bead portion as a member for fixing the tire to a rim is arranged. After forming into a toroidal shape, a tread is attached to the central portion of the outer periphery, and a sidewall is bonded to the radially outer side to form a side portion, thereby producing an unvulcanized tire.

[0151] Thereafter, the unvulcanized tire produced as described above is heated and pressurized in a vulcanizer to obtain a tire. The vulcanization process can be carried out by applying known vulcanization means. The vulcanization temperature is, for example, above 120°C and below 200°C, and the vulcanization time is, for example, above 5 minutes and below 15 minutes.

[0152] As described above, the tire obtained has, as described above, the effect of the sipe formed with appropriate twist and the effect of the rubber composition with an appropriate carbon black content working together to improve the wear resistance of the tire and to improve the grip performance in the later stage.

[0153] And the tire according to the present invention can be preferably used as a passenger car tire, a large passenger car tire, a large SUV tire, a truck / bus tire, a two-wheeler tire, a racing tire, a studless tire (winter tire), an all-season tire, a run-flat tire, etc., and particularly preferably as a passenger car tire.

Example

[0154] Hereinafter, examples (embodiments) considered preferable for implementation are shown, but the scope of the present invention is not limited to the said embodiments.

[0155] Assuming a tire (tire size: 175 / 60R18) composed of a tread formed from various compounding materials shown below and other rubber members, the results calculated based on the following evaluation method are shown in Table 1.

[0156] 1. Preparation of Rubber Composition A tread rubber composition is prepared using the following various compounding materials.

[0157] (1) Compounding Materials (a) Rubber Components (i) NR: TSR20 (ii) SBR: HPR840 (S-SBR) manufactured by ENEOS MATERIALS (Styrene content: 10% by mass, vinyl content: 42% by mass) (iii) BR: Ube Pol BR150B (high cis BR) manufactured by Ube Industries, Ltd. (Cis content 97% by mass, trans content 2% by mass, vinyl content 1% by mass)

[0158] (b) Compounding Materials Other than Rubber Components (i) Carbon Black: Dia Black N220 manufactured by Mitsubishi Chemical Corporation (N2SA: 115 m 2 / g) (ii) Silica: Ultra Sil VN3 manufactured by EPONICS INDUSTRIES (N2SA: 175 m 2 / g, average primary particle diameter: 17 nm) (iii) Silane Coupling Agent: NXT manufactured by Momentive (3-Octanoylthiopropyltriethoxysilane) (iv) Oil: Process Oil A / OMIX manufactured by Sankyo Yuka Kogyo Co., Ltd. (v) Resin: YS Resin PX850 manufactured by Yasuhara Chemical Co., Ltd. (Softening point 85°C, β-pinene resin (terpene resin)) (vi) Wax: Oz Ace 0355 manufactured by Nippon Seiro Co., Ltd. (vii) Antioxidant - 1: No Crack 6C manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) (viii) Antioxidant - 2: No Crack RD manufactured by Ouchi Shinko Chemical Industrial Co., Ltd. (Poly(2,2,4-trimethyl-1,2-dihydroquinoline)) (Li) Stearic acid: Bead stearic acid "Tsubaki" manufactured by NOF Corporation (Nu) Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. (Ru) Sulfur: Powder sulfur manufactured by Karuizawa Sulfur Co., Ltd. (Wo) Accelerator - 1: Nocceler CZ - G (CBS) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N - cyclohexyl - 2 - benzothiazolylsulfenamide) (Wa) Accelerator - 2: Nocceler D (DPG) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (1,3 - diphenylguanidine)

[0159] (2) Preparation of rubber composition for tread Based on each formulation shown in Table 1, using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd., materials other than sulfur and vulcanization accelerator were kneaded at 150 °C for 5 minutes to obtain a kneaded product.

[0160] Next, sulfur and vulcanization accelerator were added to the kneaded product, and it was kneaded for 5 minutes at 80 °C using an open roll to obtain each rubber composition for tread.

[0161] 2. Molding of tread Next, using the rubber composition obtained above, it was molded into a tread of a predetermined shape in which a twist sipe was formed so that the width was 2 mm or less, the depth was 20 mm or less, and the ratio X of the area of the intersection of the opening and the groove bottom was 95% or less.

[0162] 3. Manufacture of tire Next, the tread obtained above was bonded together with other tire members to form an unvulcanized tire, which was press - vulcanized at 170 °C for 10 minutes to manufacture test tires of Examples 1 to 4 and Comparative Examples 1 to 4.

[0163] 4. Performance evaluation test The performance evaluation test was conducted for wear resistance performance evaluation and grip performance evaluation in the later stage of wear, and further, a comprehensive evaluation was conducted based on the evaluation results of both.

[0164] First, as a prerequisite for each evaluation, each test tire is mounted on all four wheels of a vehicle (a domestic FF vehicle with a displacement of 2000 cc), filled with air so that the internal pressure becomes 230 kPa, and driven on a test course on a dry asphalt road surface for 50,000 km.

[0165] Also, as a reference example tire, a tire manufactured by replacing all of the SBR in the formulation of Comparative Example 3 with NR is used to perform the same driving.

[0166] (1) Evaluation of wear resistance The wear resistance evaluation is performed by comparing before and after driving and calculating the wear amount of the tread portion. Specifically, taking the result in Comparative Example 1 as 100, it is indexed based on the following formula to obtain the wear resistance performance evaluation. The larger the numerical value, the less the wear amount and the better the wear resistance. Wear resistance performance = [(result of Comparative Example 1) / (result of the test tire)] × 100

[0167] (2) Evaluation of grip performance in the late stage of wear The grip performance evaluation in the late stage of wear is performed by time attack using each tire after driving 50,000 km. Specifically, each test tire is mounted on all four wheels of a vehicle (a domestic FF vehicle with a displacement of 2000 cc), filled with air so that the internal pressure becomes 230 kPa, and then driven on a test course on a dry asphalt road surface for 15 laps of actual vehicle driving, and the driving time is measured. Also, the time of the reference example tire is measured in the same way.

[0168] Then, based on the reference example tire, the shortened driving time of each test tire is calculated.

[0169] Next, taking the shortened driving time in Comparative Example 1 as 100, it is indexed based on the following formula to obtain the grip performance evaluation in the late stage of wear. The larger the numerical value, the better the grip performance in the late stage of wear. Grip performance in the late stage of wear = [(result of the test tire) / (result of Comparative Example 1)] × 100

[0170] (3) Comprehensive Evaluation Then, the wear resistance performance evaluation result and the grip performance evaluation result in the later wear stage are added together to obtain a comprehensive evaluation.

[0171]

Table 1

[0172] As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

[0173] The present invention (1) is a tire having a tread portion, wherein a groove having a width of 2 mm or less and a depth of 20 mm or less, which has an opening facing the surface of the tread portion and a groove bottom, is formed in the land portion on the surface of the tread portion, the opening and the groove bottom intersect when the surface of the tread portion is viewed in plan, the ratio X of the area of the intersection portion of the opening and the groove bottom to the area of the opening when the surface of the tread portion is viewed in plan is 95% or less, the tread portion is formed of a rubber composition containing a rubber component and carbon black, and the content (parts by mass) Y of the carbon black is 20 parts by mass or more with respect to 100 parts by mass of the rubber component, and further, it is a tire characterized in that X / Y < 4.

[0174] The present invention (2) is characterized in that X is 80% or less, and it is the tire according to the present invention (1).

[0175] The present invention (3) is characterized in that X is 60% or less, and it is the tire according to the present invention (2).

[0176] The present invention (4) is The tire according to the present invention (2) or (3), characterized in that X is 1% or more.

[0177] The present invention (5) is The tire according to the present invention (1), characterized in that Y is 30 parts by mass or more.

[0178] The present invention (6) is The tire according to the present invention (5), characterized in that Y is 40 parts by mass or more.

[0179] The present invention (7) is The tire according to the present invention (5) or (6), characterized in that Y is 90 parts by mass or less.

[0180] The present invention (8) is The tire according to the present invention (1), characterized in that X / Y is 3.5 or less.

[0181] The present invention (9) is The tire according to the present invention (8), characterized in that X / Y is 2.5 or less.

[0182] The present invention (10) is The tire according to the present invention (8) or (9), characterized in that X / Y is 0.3 or more.

[0183] The present invention (11) is The tire according to the present invention (1), characterized in that the thickness of the tread portion is 10 mm or more and 20 mm or less.

[0184] The present invention (12) is The tire according to the present invention (1), characterized in that the tread portion is formed of a plurality of layers having a cap rubber layer as the outermost layer.

[0185] The present invention (13) is The tire according to the present invention (12), characterized in that the thickness of the cap rubber layer in the entire tread portion is 10% or more.

[0186] The present invention (14) is The tire according to the present invention (13), characterized in that the thickness of the cap rubber layer in the entire tread portion is 70% or more.

[0187] The present invention (15) is The tire according to the present invention (1), characterized in that the aspect ratio is 30% or more and 60% or less.

[0188] The present invention (16) is The tire according to the present invention (1), characterized in that the rubber composition contains styrene-butadiene rubber (SBR) with a styrene content of 25% by mass or less.

[0189] The present invention (17) is The tire according to the present invention (16), characterized in that the content of styrene-butadiene rubber (SBR) in 100 parts by mass of the rubber component is 40 parts by mass or more.

[0190] The present invention (18) is The tire according to the present invention (1), characterized in that the content of isoprene rubber in 100 parts by mass of the rubber component of the rubber composition is 40 parts by mass or more.

[0191] The present invention (19) is The tire according to the present invention (1), characterized in that the content of butadiene rubber (BR) in 100 parts by mass of the rubber component of the rubber composition is 5 parts by mass or more.

[0192] The present invention (20) is The tire according to the present invention (1), characterized in that the rubber composition contains at least one resin component selected from rosin resins, styrene resins, coumarone resins, terpene resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins.

Description of Symbols

[0193] 1 Land part 2 Opening 3 Groove bottom S Intersection

Claims

1. A tire comprising a tread portion, wherein a groove having a width of 2 mm or less and a depth of 20 mm or less, which has an opening facing the surface of the tread portion and a groove bottom, is formed in the land portion on the surface of the tread portion, the opening and the groove bottom intersect when the surface of the tread portion is viewed in plan, the ratio X of the area of the intersection portion of the opening and the groove bottom to the area of the opening when the surface of the tread portion is viewed in plan is 95% or less, the tread portion is formed of a rubber composition containing a rubber component and carbon black, and the content (parts by mass) Y of the carbon black is 20 parts by mass or more with respect to 100 parts by mass of the rubber component, furthermore, a tire characterized in that X / Y < 4.

2. The tire according to claim 1, wherein X is 80% or less.

3. The tire according to claim 2, wherein X is 60% or less.

4. The tire according to claim 2 or claim 3, wherein X is 1% or more.

5. The tire according to claim 1, wherein Y is 30 parts by mass or more.

6. The tire according to claim 5, wherein Y is 40 parts by mass or more.

7. The tire according to claim 5 or claim 6, wherein Y is 90 parts by mass or less.

8. The tire according to claim 1, wherein X / Y is 3.5 or less.

9. The tire according to claim 8, wherein X / Y is 2.5 or less.

10. The tire according to claim 8 or claim 9, wherein X / Y is 0.3 or more.

11. The tire according to claim 1, wherein the thickness of the tread portion is 10 mm or more and 20 mm or less.

12. The tire according to claim 1, wherein the tread portion is formed of a plurality of layers having a cap rubber layer as the outermost layer.

13. The tire according to claim 12, wherein the thickness of the cap rubber layer in the entire tread portion is 10% or more.

14. The tire according to claim 13, wherein the thickness of the cap rubber layer in the entire tread portion is 70% or more.

15. The tire according to claim 1, wherein the aspect ratio is 30% or more and 60% or less.

16. The tire according to claim 1, characterized in that the rubber composition contains a styrene-butadiene rubber (SBR) having a styrene content of 25% by mass or less.

17. The tire according to claim 16, characterized in that the content in 100 parts by mass of the rubber component of the styrene-butadiene rubber (SBR) is 40 parts by mass or more.

18. The tire according to claim 1, characterized in that the content of the isoprene-based rubber in 100 parts by mass of the rubber component of the rubber composition is 40 parts by mass or more.

19. The tire according to claim 1, characterized in that the content of the butadiene rubber (BR) in 100 parts by mass of the rubber component of the rubber composition is 5 parts by mass or more.

20. The tire according to claim 1, characterized in that the rubber composition contains at least one resin component selected from rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins.

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