Tire

Abstract

The present invention further improves overall performance including wear resistance performance and wet grip performance. This tire comprises a tread portion having a land part in which a groove with a width of 2 mm or less and a depth of 20 mm or less is provided such that, when viewed in plan from the surface of the tread portion, two or more intersecting parts where an opening part and a groove bottom part of the groove, which is twisted in shape, intersect with each other are provided so as to be spaced apart from each other in a longitudinal direction. The total of the areas of the intersecting parts is 95% or less relative to the area of the opening part when viewed in plan from the surface of the tread portion. The tread portion is formed of a rubber composition containing a rubber component and 20 parts by mass or more of a reinforcement filler with respect to 100 parts by mass of the rubber component. When the number of intersecting parts per groove is X and the content of the reinforcement filler is Y (parts by mass), X × Y > 100.

Description

tire

[0001] The present invention relates to a tire.

[0002] Since the wear resistance and grip performance of a tire are in a trade-off relationship, it is not easy to achieve both. Under these circumstances, Patent Document 1 describes a tire in which grooves are formed on the surface of the tread portion formed from a rubber composition containing a rubber component and a filler, but this is still not sufficient, and further improvement in the overall performance of the wear resistance and grip performance (particularly wet grip performance) is desired.

[0003] Japanese Patent Application Laid-Open No. 2023-149903

[0004] An object of the present invention is to further improve the overall performance of wear resistance and wet grip performance.

[0005] The present invention provides a tire having a tread portion, wherein a land portion of the tread portion has grooves each having a width of 2 mm or less and a depth of 20 mm or less, which are twisted when viewed in a plane from the surface of the tread portion, and two or more intersections where an opening of the groove intersects with a groove bottom of the groove are formed in the longitudinal direction and spaced apart from each other, the total area of ​​the intersections being 95% or less of the area of ​​the opening when viewed in a plane from the surface of the tread portion, the tread portion is formed from a rubber composition containing a rubber component and 20 parts by mass or more of a reinforcing filler per 100 parts by mass of the rubber component, and further wherein, where X (number of intersections) per groove is X and Y (parts by mass) is the content of the reinforcing filler, X×Y>100.

[0006] According to the present invention, it is possible to further improve the overall performance of wear resistance and wet grip performance.

[0007] FIG. 2 is a diagram illustrating sipes in a tire according to the present invention.

[0008] [1] Characteristics of the tire according to the present disclosure First, the characteristics of the tire according to the present disclosure will be described.

[0009] 1. Overview A tire according to the present invention has a tread portion, and the land portions of the tread portion are provided with grooves having a width of 2 mm or less and a depth of 20 mm or less, which are twisted in a planar view from the surface of the tread portion, and two or more intersections, where the groove openings and groove bottoms intersect, are formed in the longitudinal direction and spaced apart from one another. The sum of the areas of the intersections (total area) is 95% or less of the area of ​​the openings when viewed in a planar view from the surface of the tread portion. The tread portion is formed from a rubber composition containing a rubber component and 20 parts by mass or more of a reinforcing filler per 100 parts by mass of the rubber component. Furthermore, when the number of intersections per groove is X (number of intersections) and the content of the reinforcing filler is Y (parts by mass), X × Y > 100.

[0010] These features make it possible to further improve the overall performance of the tire, including wear resistance and wet grip performance.

[0011] 2. Mechanism for manifesting the effects in the tire according to the present disclosure The mechanism for manifesting the above-described effects in the tire according to the present disclosure is believed to be as follows.

[0012] (1) Twisted Sipe When grooves (sipes) having an opening facing the surface of the tread and a groove bottom are provided in the land portion of the tread, the wet grip performance of the tire can be improved, but on the other hand, the wear resistance of the tire may be reduced.

[0013] Therefore, in the present invention, as described above, sipes (hereinafter also referred to as "twisted sipes") are formed so that when viewed in plan from the surface of the tread portion, they have a twisted shape, and two or more intersections where the groove opening and groove bottom intersect are formed spaced apart in the longitudinal direction. By forming such twisted sipes, it is possible to improve wet grip performance and wear resistance.

[0014] In other words, the drainage function of the sipes improves wet grip performance, while the use of twisted sipes as described above can disperse the energy that the tire receives from the road surface, improving wear resistance, so it is thought that wet grip performance can be improved as well as wear resistance.

[0015] In this case, if the sum of the areas of the intersections (total area) is not small enough, it may not be possible to sufficiently improve wet grip performance and wear resistance. Therefore, in the present invention, the sum of the areas of the intersections (total area) is set to 95% or less of the area of ​​the opening when viewed in plan from the surface of the tread portion, which is thought to enable further improvement in the overall performance of wear resistance and wet grip performance.

[0016] Fig. 1 is a diagram illustrating sipes in a tire according to the present invention. In Fig. 1, 1 is a land portion, 2 is a groove (twisted sipe), 2t is an opening, and 2b is a groove bottom. S1 to S4 are intersections where the opening 2t and the groove bottom 2b intersect, and are spaced apart from each other.

[0017] As shown in Figure 1(a), in the present invention, sipes formed in a twisted shape with a predetermined width and length are provided so that the shape changes from the opening 2t to the groove bottom 2b. As a result, as shown in Figure 1(b), when the opening 2t and the groove bottom 2b are viewed in plan from the surface of the tread portion, intersections S1 to S4 can be formed.

[0018] In this case, as described above, by controlling the sum of the areas (total area) of the intersections S1 to S4 to be 95% or less of the area of ​​the opening 2t, it is possible to further improve the overall performance of the wear resistance and wet grip performance.

[0019] In FIG. 1, the opening and the groove bottom do not intersect at both ends, and the number of intersections is one less than the number of twists. However, both ends may intersect (the number of intersections is one more than the number of twists), or either end may intersect (the number of intersections is the same as the number of twists).

[0020] (2) Inclusion of Reinforcing Filler in Rubber Composition Forming Tread Portion In the present invention, the tread portion is formed of a rubber composition (tread rubber composition) containing a rubber component and 20 parts by mass or more of a reinforcing filler per 100 parts by mass of the rubber component, as described above.

[0021] By including a reinforcing filler in the rubber composition for tread, it is possible to appropriately control tire wear and ensure the rigidity of the tread portion, and therefore it is thought that the overall performance of the rubber composition, including wear resistance and wet grip performance, can be further improved.

[0022] (3) Relationship between the number of intersections and the content of reinforcing filler In the present invention, the number X (number of intersections) per groove and the content Y (parts by mass) of reinforcing filler satisfy X × Y > 100.

[0023] This allows the effects of the tire shape due to the formation of twisted sipes and the effects of the rubber composition due to the inclusion of reinforcing fillers to be exerted in cooperation, which is thought to further improve the overall performance of wear resistance and wet grip performance.

[0024] [2] More preferred aspects of the tire according to the present disclosure The tire according to the present disclosure can achieve even greater effects by adopting the following aspects.

[0025] 1. Twisted sipes

[0026] (1) Total Area Ratio of Intersections As described above, in the present invention, the total area of ​​the intersections when viewed in plan from the surface of the tread is 95% or less, more preferably 90% or less, and even more preferably 70% or less, of the area of ​​the openings when viewed in plan from the surface of the tread. The lower limit is, for example, preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and even more preferably 50% or more.

[0027] (2) Size As described above, in the present invention, the size of the twisted sipe is 2 mm or less in width and 20 mm or less in depth, but the width is preferably less than 1.8 mm, more preferably less than 1.5 mm, even more preferably less than 1.2 mm, and particularly preferably less than 0.9 mm. The lower limit is preferably more than 0.1 mm, more preferably more than 0.2 mm, even more preferably more than 0.3 mm, and even more preferably 0.6 mm or more.

[0028] The depth is preferably 18 mm or less, more preferably less than 15 mm, even more preferably less than 10 mm, still more preferably 6 mm or less, and particularly preferably less than 6 mm. The lower limit is preferably more than 1 mm, more preferably more than 2 mm, even more preferably more than 3 mm, and particularly preferably more than 4 mm. The length is preferably about 10 mm.

[0029] (3) Number of Intersections As described above, in the present invention, the number of intersections is 2 or more, more preferably 3 or more, even more preferably 4 or more, and particularly preferably 5 or more. There is no particular upper limit, but it is preferably 10 or less, more preferably 9 or less, even more preferably 8 or less, and particularly preferably 7 or less.

[0030] 2. Content of Reinforcing Filler in Tread Rubber Composition In the present invention, as described above, the rubber composition for a tread contains 20 parts by mass or more of a reinforcing filler per 100 parts by mass of the rubber component. More than 40 parts by mass is more preferable, more than 60 parts by mass is more preferable, more than 80 parts by mass is even more preferable, more than 100 parts by mass is even more preferable, and 110 parts by mass or more is even more preferable. The upper limit is not particularly limited, but is preferably less than 180 parts by mass, more preferably less than 160 parts by mass, even more preferably 150 parts by mass or less, even more preferably 140 parts by mass or less, even more preferably 140 parts by mass or less, even more preferably 130 parts by mass or less, and even more preferably less than 120 parts by mass.

[0031] Examples of reinforcing fillers include silica, carbon black, graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. Among these, silica and carbon black are preferred, and a combination of both is more preferred. When silica is used, it is preferred to use it in combination with a silane coupling agent.

[0032] The content of silica per 100 parts by mass of the rubber component is preferably more than 15 parts by mass, more preferably more than 35 parts by mass, even more preferably more than 55 parts by mass, and even more preferably more than 70 parts by mass. It is believed that increasing the content of silica can improve the wear resistance of the tire and also improve the wet grip performance. From the viewpoint of dispersibility in the rubber composition, the upper limit is preferably less than 150 parts by mass, more preferably less than 130 parts by mass, even more preferably 120 parts by mass or less, even more preferably 110 parts by mass or less, even more preferably less than 110 parts by mass, and even more preferably 100 parts by mass or less.

[0033] The amount of carbon black per 100 parts by mass of the rubber component is preferably more than 1 part by mass, more preferably more than 5 parts by mass, even more preferably 10 parts by mass or more, even more preferably more than 10 parts by mass, and even more preferably 20 parts by mass or more. The upper limit is not particularly limited, but is preferably less than 100 parts by mass, more preferably less than 80 parts by mass, even more preferably less than 50 parts by mass, even more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.

[0034] 3. Number of Intersections X and Reinforcing Filler Content Y In the present invention, the product (X × Y) of the number of intersections X (pieces) and the reinforcing filler content Y (parts by mass) is controlled to be greater than 100, but is more preferably greater than 130, even more preferably greater than 160, even more preferably greater than 180, even more preferably greater than 200, even more preferably 220 or more, and even more preferably 300 or more. The upper limit is not particularly limited, but is preferably less than 500, more preferably 450 or less, even more preferably less than 450, even more preferably less than 400, even more preferably 390 or less, even more preferably less than 350, and even more preferably 330 or less.

[0035] 4. Tread The tread preferably has a thickness of 10 mm or more, more preferably 12 mm or more, and even more preferably 14 mm or more. There is no particular upper limit to the thickness, but it is preferably 20 mm or less, more preferably 18 mm or less, and even more preferably 16 mm or less. A plurality of land portions that come into contact with the road surface are formed on the surface of the tread. The plurality of land portions are separated from one another by grooves having a width of more than 2 mm.

[0036] The tread portion may be formed of only one layer of cap rubber, or may have a base rubber layer on the inside of the cap rubber layer, making it two layers, or may have three layers, or may have four or more layers.

[0037] 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, which is believed to enable the wear resistance and wet grip performance to be maintained.

[0038] The thickness of the tread portion mentioned above refers to the thickness of the tread portion on the tire equatorial plane in the tire radial cross section. When the tread portion is formed of a single rubber composition, it refers to the thickness of that rubber composition. When the tread portion is formed of a laminated structure of multiple rubber compositions described below, it refers to the total thickness of these layers.

[0039] In the tire according to the present disclosure, the tread portion is a component in the region that forms the contact patch of the tire, and refers to the portion radially outward of components containing fiber materials such as the carcass, belt layer, belt reinforcing layer, etc. The thickness of the tread portion can be measured in a cross section cut out in the radial direction of the tire, with the bead portion aligned with the normal rim width.

[0040] Note that a "regular rim" is a rim that is determined for each tire by a standard system that includes the standard on which the tire is based. For example, in the case of JATMA (Japan Automobile Tire Manufacturers Association), this refers to the standard rim for the applicable size listed in the "JATMA YEAR BOOK," in the case of ETRTO (The European Tyre and Rim Technical Organization), this refers to the "Measuring Rim" listed in the "STANDARDS MANUAL," and in the case of TRA (The Tire and Rim Association, Inc.), this refers to the "Design Rim" listed in the "YEAR BOOK." Reference is made to JATMA, ETRTO, and TRA in that order, and if an applicable size is available at the time of reference, that standard will be followed. In the case of tires not specified by the standard, it refers to the rim that can be mounted on a rim and can maintain internal pressure, i.e., the rim with the smallest rim diameter and the next narrowest rim width, among rims that do not cause air leakage between the rim and tire.

[0041] 5. Aspect Ratio Aspect ratio is the ratio of the tire's cross-sectional height to its cross-sectional width, and it is believed that the smaller this ratio (lower aspect ratio) the better the grip performance. On the other hand, if the aspect ratio is too low, it may lead to a deterioration in ride comfort.

[0042] Considering these points, in the tire according to the present disclosure, the aspect ratio is preferably 30% or more, and more preferably 40% or more, while the upper limit is preferably 60% or less, and more preferably 50% or less.

[0043] The above aspect ratio (%) can be calculated using the tire cross-sectional height Ht (mm), cross-sectional width Wt (mm), tire outer diameter Dt (mm), and rim diameter R (mm) when the internal pressure is set to 250 kPa, using the following formula: Aspect ratio (%) = (Ht / Wt) x 100 (%) Ht = (Dt - R) / 2

[0044] 6. Rubber Composition (1) Rubber Component The rubber composition constituting the tread portion of the tire according to the present disclosure preferably contains, as the rubber component, styrene-butadiene rubber (SBR) with a low styrene content (mass ratio). When such SBR is contained, it is possible to form minute styrene domains in the rubber matrix, which is thought to improve wear resistance while maintaining wet grip performance provided by the sipes.

[0045] Specifically, the styrene content of the SBR is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, while the lower limit is preferably 4% by mass or more, more preferably 5% by mass or more, and even more preferably 6% by mass or more.

[0046] The above-mentioned SBR with a styrene content of 25% by mass or less means that when a single styrene-containing polymer (SBR) is contained 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, the styrene content calculated by the sum of the product of the styrene content (% by mass) in each polymer and the blending amount (parts by mass) of that polymer per 100 parts by mass of the rubber component is 25% by mass or less.

[0047] More specifically, when 100 parts by mass of the rubber component contains 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, the styrene content calculated from the formula {(S1×X1)+(S2×X2)} / (X1+X2) is 25% by mass or less.

[0048] In addition, in the case of a rubber composition after vulcanization, the styrene content can also be calculated by determining the amount of styrene contained in the rubber component after acetone extraction using solid-state nuclear magnetic resonance (solid-state NMR) or Fourier transform infrared spectroscopy (FTIR).

[0049] (2) Inclusion of Resin Component The rubber composition forming the tread preferably contains a resin component.

[0050] It is believed that by including a resin component in the rubber composition, the adhesiveness of the resin component can maintain grip on the road surface, further improving later grip performance.

[0051] Preferred resin components include rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins, which will be described later, and of these, terpene-based resins are more preferred.

[0052] [3] Embodiments Hereinafter, a tire according to the present disclosure will be specifically described based on embodiments.

[0053] 1. 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, oil, a resin material, and an antioxidant.

[0054] (1) Compounding Materials (a) Rubber Component (a) SBR As described above, it is preferable to use low-styrene SBR as the SBR. The weight-average molecular weight of the SBR is, for example, more than 100,000 and less than 2,000,000. The vinyl content (amount of 1,2-bonded butadiene units) of the SBR is, for example, preferably 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. The structural identification of the SBR (measurement of the styrene content and vinyl content) can be performed using, for example, a JNM-ECA series instrument manufactured by JEOL Ltd.

[0055] The SBR is not particularly limited, and examples thereof include emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR). The SBR may be either unmodified or modified. Hydrogenated SBR, in which the butadiene portion of SBR is hydrogenated, may also be used. Hydrogenated SBR may be obtained by subsequently hydrogenating the BR portion of SBR, or a similar structure may be obtained by copolymerizing styrene, ethylene, and butadiene.

[0056] The modified SBR is preferably an SBR having a functional group that interacts with a filler such as silica. Examples include terminal-modified SBR in which at least one terminal of the SBR has been modified with a compound (modifying agent) having the above functional group (terminal-modified SBR having the above functional group at the terminal), main-chain-modified SBR in which the main chain has the above functional group, main-chain-terminal-modified SBR in which the main chain and the terminals have the above functional group (for example, main-chain-terminal-modified SBR in which the main chain has the above functional group and at least one terminal has been modified with the above modifier), and terminal-modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and into which a hydroxyl group or epoxy group has been introduced.

[0057] Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, an epoxy group, etc. These functional groups may have a substituent.

[0058] Furthermore, as the modified SBR, for example, SBR modified with a compound (modifying agent) represented by the following formula can be used.

[0059]

[0060] In the formula, R １ , R ２ and R ３are 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. ４ and R ５ are the same or different and represent a hydrogen atom or an alkyl group. ４ and R ５ may bond to form a ring structure together with the nitrogen atom, and n represents an integer.

[0061] As the modified SBR modified with the compound (modifying agent) represented by the above formula, SBR in which the polymerization terminals (active terminals) of solution-polymerized styrene-butadiene rubber (S-SBR) have been modified with the compound represented by the above formula (such as the modified SBR described in JP 2010-111753 A).

[0062] R １ , R ２ and R ３ is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). ４ and R ５ is 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 even more preferably 3. ４ and R ５ When the groups bond to form a ring structure together with the nitrogen atom, the ring is preferably a 4- to 8-membered ring. The alkoxy group also includes a cycloalkoxy group (e.g., a cyclohexyloxy group) and an aryloxy group (e.g., a phenoxy group, a benzyloxy group).

[0063] Specific examples of the modifying agent 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.

[0064] Furthermore, modified SBR modified with the following compounds (modifiers) can also be used as the modified SBR. Examples of the modifier include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and 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, and polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline; Diglycidylamino compounds such as diglycidyl orthotoluidine, tetraglycidyl meta-xylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and 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, and N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(trippropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxy sulfide group-containing silane compounds such as (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, Alkoxysilanes such as thyltriethoxysilane; (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, and N,N,N',N'-bis-(tetraethylamino)benzophenone; Benzaldehyde compounds having an amino group and / or a substituted amino group, such as dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, and 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, and N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurylolactam, N-vinyl-ω-laurylolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam, as well as N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), and tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones , 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-dimethylaminoacetophen, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. Modification with the above compounds (modifiers) can be carried out by known methods.

[0065] Examples of SBR that can be used include SBR and modified SBR manufactured and sold by Sumitomo Chemical Co., Ltd., ENEOS Materials Corporation, Asahi Kasei Corporation, and Zeon Corporation. SBR may be used alone or in combination of two or more types.

[0066] The amount of SBR per 100 parts by mass of the rubber component is preferably 25 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 35 parts by mass or more, and still more preferably 40 parts by mass or more. The upper limit is, for example, preferably 55 parts by mass or less, more preferably 50 parts by mass or less, and still more preferably 45 parts by mass or less.

[0067] (b) Isoprene-based rubber Examples of isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR, with NR being preferred due to its excellent strength.

[0068] Examples of NR include SVR-L, SIR20, RSS#3, and TSR20, which are commonly used in the tire industry. Examples of IR include IR2200 manufactured by Zeon Corporation, which is commonly used in the tire industry. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0069] The content of the isoprene-based 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, even more preferably 45 parts by mass or more, and still more preferably 50 parts by mass or more. The upper limit is, for example, preferably 65 parts by mass or less, more preferably 60 parts by mass or less, and still more preferably 55 parts by mass or less.

[0070] (C) BR Butadiene rubber (BR) may be used as the rubber component, if necessary. The weight average molecular weight of the BR is, for example, more than 100,000 and less than 2,000,000. The vinyl content of the BR is, for example, more than 1% by mass and less than 30% by mass. The cis content of the BR is, for example, more than 1% by mass and 98% by mass or less. The trans content of the 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.

[0071] The BR is not particularly limited, and can be BR with a high cis content (cis content of 90% or more), BR with a low cis content, BR containing syndiotactic polybutadiene crystals, etc. The BR can be either unmodified BR or modified BR, and the modified BR can be, for example, BR modified with a compound (modifier) ​​represented by the following formula:

[0072]

[0073] In the formula, R １ , R ２ and R ３are 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. ４ and R ５ are the same or different and represent a hydrogen atom or an alkyl group. ４ and R ５ may bond to form a ring structure together with the nitrogen atom, and n represents an integer.

[0074] The modified BR modified with the compound (modifying agent) represented by the above formula includes BR whose polymerization terminal (active terminal) has been modified with the compound represented by the above formula.

[0075] R １ , R ２ and R ３ is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). ４ and R ５ is 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 even more preferably 3. ４ and R ５ When the groups bond to form a ring structure together with the nitrogen atom, the ring is preferably a 4- to 8-membered ring. The alkoxy group also includes a cycloalkoxy group (e.g., a cyclohexyloxy group) and an aryloxy group (e.g., a phenoxy group, a benzyloxy group).

[0076] Specific examples of the modifying agent 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.

[0077] The modified BR may also be modified with the following compounds (modifiers): Examples of the modifier include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and 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, and polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline; Diglycidylamino compounds such as diglycidyl orthotoluidine, tetraglycidyl meta-xylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and 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, and N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(trippropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxy sulfide group-containing silane compounds such as (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyl alkoxysilanes 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, and N,N,N',N'-bis-(tetraethylamino)benzophenone; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-di Benzaldehyde compounds having an amino group and / or a substituted amino group, such as methylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, and 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, and N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurylolactam, N-vinyl-ω-laurylolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam, as well as N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), and tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones , 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-dimethylaminoacetophen, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. Modification with the above-mentioned compounds (modifying agents) can be carried out by known methods. These modified BRs may be used alone or in combination of two or more.

[0078] As the BR, for example, products of Ube Industries, Ltd., ENEOS Materials Corporation, Asahi Kasei Corporation, Zeon Corporation, etc. can be used.

[0079] The amount of BR per 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, and even more preferably 10 parts by mass or more, and is preferably 15 parts by mass or less, and more preferably 12 parts by mass or less.

[0080] (d) Other Rubber Components The rubber composition may contain, as other rubber components, rubbers (polymers) that are generally used in the production of tires, such as nitrile rubber (NBR), as necessary.

[0081] (e) Recycled Monomers The raw materials (monomers) for the above-mentioned synthetic rubbers such as SBR and BR may be derived from petroleum or may be recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0082] Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples thereof include recycled butadiene and recycled aromatic vinyl. Examples of the butadienes include 1,2-butadiene and 1,3-butadiene. Examples of the aromatic vinyls include styrene, and are not particularly limited. Among these, it is preferable to use recycled butadiene (recycled butadiene) and / or recycled styrene (recycled styrene) as raw materials.

[0083] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0084] (f) Biomass Monomers Furthermore, the raw materials (monomers) for synthetic rubbers such as SBR and BR may be derived from biomass. Examples of biomass-derived monomers (biomass monomers) include, but are not limited to, biomass-derived butadiene and biomass-derived aromatic vinyl. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl include, but are not limited to, styrene. Furthermore, methods for producing biomass monomers are not particularly limited, and include, for example, biological and / or chemical and / or physical conversion of animals and plants. A typical example of biological conversion is fermentation using microorganisms, while examples of chemical and / or physical conversion include catalytic, high-temperature, high-pressure, electromagnetic, critical fluid, and combinations thereof. Biomass sources for these monomers include sugar, wood, plant residues after useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0085] The polymer synthesized from a biomass monomer component (biomass polymer) is not particularly limited, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0086] Whether the raw material of a polymer is derived from biomass can be determined by the pMC (percent modern carbon) measured in accordance with ASTM D6866-10.

[0087] pMC is the modern standard reference １４ of sample with respect to C concentration １４ This value is used as an index showing the biomass ratio of the compound (rubber). The significance of this value will be described below.

[0088] 1 mole of carbon atoms (6.02 x 10 ２３ ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. １１ pieces １４ C exists. １４ C is called a radioactive isotope, and its half-life is 5,730 years, and it decreases regularly. It takes 226,000 years for all of it to decay. Therefore, in fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when it was first fixed. １４ All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain １４ Therefore, chemical substances produced using these fossil fuels as raw materials also contain no C element. １４ The element C is not contained at all.

[0089] on the other hand, １４C is produced continuously by nuclear reactions in the atmosphere caused by cosmic rays, and in the Earth's atmospheric environment, the amount of C is balanced by the decrease caused by radioactive decay. １４ Therefore, the amount of C in the biomass resources currently circulating in the environment is １４ As mentioned above, the C concentration is about 1 × 10 －１２ Therefore, the difference between these values ​​can be used to calculate the ratio (biomass ratio) of compounds derived from natural resources (compounds derived from biomass resources) in a certain compound (rubber).

[0090] this １４ C is typically measured as follows: using accelerator mass spectrometry based on a tandem accelerator; １３ C concentration ( １３ C / １２ C), １４ C concentration ( １４ C / １２ C) is measured. １４ The modern standard reference for C concentration is the carbon circulating in nature as of 1950. １４ The specific radioactivity of carbon in this oxalic acid (carbon specific activity per gram of carbon) is used as the standard material. １４ C radioactivity intensity) for each carbon isotope, １３ The standard value is the value corrected for decay from 1950 to the measurement date. １４ The ratio of this value to the value of the actually measured sample is the pMC value.

[0091] Therefore, if rubber is made from 100% biomass (natural) derived materials, it will show a value of approximately 110 pMC, although there may be regional differences (currently, under normal conditions, it is often not 100). On the other hand, for chemical substances derived from fossil fuels such as petroleum, １４When the C concentration is measured, it will be approximately 0 pMC (for example, 0.3 pMC), which corresponds to the biomass ratio of 0% mentioned above.

[0092] From the above, it is preferable to use a material such as rubber having a high pMC value, that is, a material such as rubber having a high biomass ratio, in a rubber composition, in order to contribute to environmental protection and improve sustainability.

[0093] (b) Compounding Materials Other Than Rubber Component (a) Reinforcing Filler (i) Silica The rubber composition may contain silica as a reinforcing filler. The hydration water contained in the silica and the functional groups on the surface can capture ozone, thereby improving ozone resistance and improving tire durability.

[0094] If the average primary particle diameter of silica is too small, processability will be poor, so silica having an average primary particle diameter of more than 8 nm is preferably used. More preferably, it is more than 9 nm, and even more preferably, it is more than 10 nm. On the other hand, from the viewpoint of the abrasion resistance and wet grip performance of the rubber composition, it is preferably less than 25 nm, more preferably less than 20 nm, and even more preferably less than 17 nm.

[0095] The average primary particle size of silica refers to the average value of the values ​​obtained by observing the smallest particle unit of silica constituting the aggregate structure as a circle and measuring the absolute maximum length of the smallest particle as the diameter of the circle; the average primary particle size of silica can be determined by observing with a transmission or scanning electron microscope, measuring 400 or more primary particles of silica observed within the field of view, and averaging the measured values.

[0096] The BET specific surface area of ​​silica is set to 100 m from the viewpoint of obtaining good durability. ２ / g, and preferably more than 130m ２ On the other hand, it is more preferable that the viscosity is more than 250 m / g. ２ / g, and preferably less than 200m ２ The BET specific surface area is preferably less than N / g as measured by the BET method in accordance with ASTM D3037-93. ２ This is the SA value.

[0097] As described above, the content of silica per 100 parts by mass of the rubber component is preferably more than 15 parts by mass, more preferably more than 35 parts by mass, even more preferably more than 55 parts by mass, still more preferably more than 70 parts by mass, and even more preferably more than 75 parts by mass.

[0098] Examples of silica include dry process silica (anhydrous silica), wet process silica (hydrated silica), and colloidal silica. Among these, wet process silica is preferred because it contains water of hydration and a large number of silanol groups, and can effectively capture ozone. Alternatively, silica made from hydrous glass or silica made from biomass materials such as rice husks may also be used.

[0099] As silica, products available from Evonik Industries, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd., Tokuyama Corporation, etc. can be used.

[0100] The raw material for silica is not particularly limited, and may be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from a biomass material such as rice husk), or silica recycled from a product containing silica. Among these, hydrated silica prepared by a wet method is preferred because it contains a large number of silanol groups.

[0101] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet-process silica to produce a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0102] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0103] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, it is possible to suppress the crystallization of silica in rice husk ash (see, for example, JP 2009-2594 A and Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222).

[0104] Amorphous silica extracted from rice husks may be commercially available from Wilmar Co., Inc., etc.

[0105] These silicas may be used alone or in combination of two or more. The use of biomass silica or recycled silica is preferred from the viewpoint of contributing to environmental protection and improving sustainability.

[0106] (ii) Silane Coupling Agent When silica is used, it is preferable to use a silane coupling agent in combination in order to increase the dispersibility of the silica and to improve the mechanical properties and moldability by reacting with the silica.

[0107] The silane coupling agent is not particularly limited, and examples thereof include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, and bis(4-trimethoxysilylbutyl)trisulfide. Sulfide, 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-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilyl Examples of suitable silane coupling agents include sulfide-based agents such as ethyl-N,N-dimethylthiocarbamoyl tetrasulfide and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based agents such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z; vinyl-based agents such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based agents such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based agents such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based agents such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based agents such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Of these, preferred are silane coupling agents having a thiocarbonyl group, such as the above-mentioned NXT. These may be used alone or in combination of two or more.

[0108] As the silane coupling agent, for example, products from Evonik Industries, Momentive, Shin-Etsu Silicones, Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., DuPont Toray Specialty Materials, Inc., etc. can be used.

[0109] The content of the silane coupling agent is, for example, preferably more than 3 parts by mass, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, relative to 100 parts by mass of silica. The upper limit is, for example, preferably less than 15 parts by mass, more preferably 12 parts by mass or less, and even more preferably 10 parts by mass or less.

[0110] (iii) Carbon Black Carbon black may be used as the reinforcing filler. Carbon black is used from the viewpoint of improving the crack growth resistance, durability, resistance to ultraviolet degradation, etc. of the tire, thereby improving the abrasion resistance and webbing grip performance.

[0111] The nitrogen adsorption specific surface area of ​​carbon black (N ２ From the viewpoint of reinforcing the rubber, SA) is, for example, 30 m ２ / g or more, and ２ / g or more is more preferable, and 60m ２ On the other hand, from the viewpoint of heat buildup, it is more preferable that the solubility is 250 m / g or more. ２ / g or less, and ２ / g or less is more preferable, and 120m ２ The nitrogen adsorption specific surface area of ​​carbon black is measured in accordance with ASTM D4820-93.

[0112] From the viewpoint of rubber rigidity, the dibutyl phthalate (DBP) absorption of carbon black is preferably, for example, 50 ml / 100 g or more, and more preferably 100 ml / 100 g or more. On the other hand, from the viewpoint of rubber compliance with deformation, it is preferably 250 ml / 100 g or less, and more preferably 150 ml / 100 g or less. The DBP absorption of carbon black is measured in accordance with ASTM D2414-93.

[0113] The carbon black is not particularly limited, and examples thereof include furnace blacks (furnace carbon blacks) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal blacks (thermal carbon blacks) such as FT and MT; and channel blacks (channel carbon blacks) such as EPC, MPC, and CC. These may be used alone or in combination of two or more.

[0114] In addition to carbon black made from mineral oil or the like, biomass-derived carbon black obtained by burning lignin or the like, or recycled carbon black obtained by pyrolyzing and purifying rubber products containing carbon black, such as tires, may be used as appropriate by replacing them in equal amounts.

[0115] Specific carbon blacks are not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. Commercially available carbon blacks include those manufactured by Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shinnikka Carbon Co., Ltd., and Columbia Carbon Co., Ltd., and these may be used alone or in combination of two or more.

[0116] As described above, the amount of carbon black per 100 parts by mass of the rubber component is preferably more than 1 part by mass, more preferably more than 5 parts by mass, and even more preferably more than 10 parts by mass. The upper limit is not particularly limited, but is preferably less than 100 parts by mass, more preferably less than 80 parts by mass, and even more preferably less than 50 parts by mass.

[0117] (iv) Other Fillers In addition to the above-mentioned silica and carbon black, the rubber composition may further contain fillers commonly used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, magnesium sulfate, etc. The content of these fillers is, for example, more than 0.1 part by mass and less than 150 parts by mass per 100 parts by mass of the rubber component.

[0118] (B) Plasticizer Component Considering the proper dispersion of powder materials during kneading, it is preferable to use a plasticizer component in the rubber composition as needed. Here, the term "plasticizer component" refers to a substance that plasticizes the rubber composition, such as process oil, rubber component advance oil, liquid rubber, or resin component. These softeners may be derived from petroleum, biomass, or naphtha recycled from rubber or non-rubber products. Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as plasticizers. Among these, biomass-derived or recycled plasticizers are preferred as sustainable plasticizers.

[0119] These plasticizers may be used alone or in combination of two or more. In this case, the content of the plasticizer component per 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. The upper limit is, for example, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.

[0120] The content of the plasticizer component also includes the amount of oil contained in rubber (oil-extended rubber) and the like.

[0121] (i) Oil Examples of oil include mineral oil, synthetic oil, vegetable oil, animal oil, and mixtures thereof.

[0122] Examples of mineral oils include paraffinic, aromatic, and naphthenic oils, and can be selected from products available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Corporation, H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., etc. These may be used alone or in combination of two or more.

[0123] From the viewpoint of life cycle assessment, lubricating oils used in the mixers and engines of rubber mixers, waste cooking oils used in restaurants, etc. may be appropriately refined and used as these oils.

[0124] Examples of vegetable oils 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, grapeseed oil, and wood wax.

[0125] Further examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above oils, interesterified oils, hydrogenated hardened oils, thermally polymerized oils, oxidatively polymerized oils, and waste edible oils recovered from edible oils. Vegetable oils may be liquid or solid at room temperature (25° C.). These may be used alone or in combination of two or more.

[0126] As the vegetable oil, acylglycerol is preferred, and triacylglycerol is more preferred. Acylglycerol refers to a compound in which a hydroxy group of glycerin is ester-bonded to a carboxylic acid. The acylglycerol is not particularly limited, and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, or a polymer of trimer or higher. Dimers or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. Acylglycerol may be liquid or solid at room temperature (25°C).

[0127] The method for confirming whether or not acylglycerol is contained in the rubber composition is not particularly limited, and may be any of the following: １ For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours, and after removing the rubber composition, the rubber composition is immersed in deuterated chloroform at room temperature. １ When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal for tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atoms of the ester groups, and therefore the presence of acylglycerol can be confirmed. Here, "around" refers to a range of ±0.10 ppm.

[0128] 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.

[0129] As the vegetable oil, for example, commercially available oils from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Corporation, H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0130] (ii) Liquid Rubber Liquid rubber is a polymer that is in a liquid state at room temperature (25°C) and is a rubber component that can be extracted by acetone extraction from a vulcanized tire. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and hydrogenated products thereof.

[0131] Farnesene polymers are polymers obtained by polymerizing farnesene, which has structural units based on farnesene. Farnesene exists as an isomer, 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).

[0132] 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).

[0133] Examples of liquid diene polymers include liquid styrene butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), and liquid styrene isoprene copolymer (liquid SIR).

[0134] The liquid diene polymer has a weight average molecular weight (Mw) of, for example, 1.0 × 10 in terms of polystyrene measured by gel permeation chromatography (GPC). ３ Super, 2.0×10 ５ Here, the Mw of the liquid diene polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0135] As the liquid rubber, for example, products of Kuraray Co., Ltd., Cray Valley Co., Ltd., etc. can be used.

[0136] (iii) Resin component The resin component also functions as a tackifier, and may be solid or liquid at room temperature. Specific examples of the resin component include rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins, and two or more of these may be used in combination. These resin components may be provided with a modifying group capable of reacting with silica, etc., as needed.

[0137] Rosin-based resins are resins whose main component is rosin acid, which is obtained by processing pine resin. These rosin-based resins (rosins) can be classified based on whether they are modified or not, and can be divided into unmodified rosin (unmodified rosin) and modified rosin (rosin derivatives). Unmodified rosins include tall rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Modified rosin is a modification of unmodified rosin, and examples thereof include rosin esters, unsaturated carboxylic acid-modified rosin esters, unsaturated carboxylic acid-modified rosin esters, rosin amide compounds, and rosin amine salts.

[0138] The styrene-based resin is a polymer using a styrene-based monomer as a constituent monomer, and examples thereof include polymers obtained by polymerizing a styrene-based monomer as the main component (50% by mass or more).Specific examples include homopolymers obtained by polymerizing each of styrene-based monomers (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 another monomer copolymerizable therewith.

[0139] Examples of the other monomer include acrylonitriles such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylics and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene and butadiene 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.

[0140] Among the coumarone resins, coumarone-indene resins are preferred. Coumarone-indene resins are resins containing coumarone and indene as monomer components constituting the resin skeleton (main chain). Monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, etc.

[0141] 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 is the amount of potassium hydroxide, expressed in milligrams, required to neutralize acetic acid bonded to hydroxyl groups when acetylating 1 g of the resin, and is a value measured by potentiometric titration (JIS K 0070:1992).

[0142] 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 the softening point specified in JIS K 6220-1:2001 is measured using a ring and ball softening point tester.

[0143] Examples of terpene resins include polyterpenes, terpene phenols, and aromatic modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are compounds having a molecular weight of (C ５ H ８ ) ｎ Monoterpenes (C １０ H １６ ), sesquiterpenes (C １５ H ２４ ), diterpenes (C ２０ H ３２), and examples thereof include α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0144] Examples of polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin, which are made from the above-mentioned terpene compounds, as well as hydrogenated terpene resins obtained by hydrogenating the terpene resins. Examples of terpene phenols include resins obtained by copolymerizing the above-mentioned terpene compounds with phenolic compounds, and resins obtained by hydrogenating the above-mentioned resins. Specific examples include resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds, and formalin. Examples of phenolic compounds include phenol, bisphenol A, cresol, and xylenol. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating the above-mentioned resins. The aromatic compound is not particularly limited as long as it is a compound having an aromatic ring, and examples thereof include phenolic compounds such as phenol, alkylphenol, alkoxyphenol, and unsaturated hydrocarbon group-containing phenol; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, and unsaturated hydrocarbon group-containing naphthol; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and unsaturated hydrocarbon group-containing styrene; coumarone, indene, and the like.

[0145] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of C5 fractions include petroleum fractions having 4 to 5 carbon atoms, such as cyclopentadiene, pentene, pentadiene, and isoprene. Dicyclopentadiene resin (DCPD resin) is preferably used as a C5 petroleum resin.

[0146] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, and may be a hydrogenated or modified version. Examples of C9 fractions include petroleum fractions having 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, indene, and methylindene. Specific examples include coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl resin. Preferred aromatic vinyl resins are α-methylstyrene (AMS resin), styrene homopolymers, and copolymers of α-methylstyrene and styrene, with copolymers of α-methylstyrene and styrene being more preferred, due to their economical efficiency, ease of processing, and excellent heat generation. Examples of aromatic vinyl resins that can be used include those commercially available from Kraton, Eastman Chemical, and the like.

[0147] The term "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be a hydrogenated or modified resin. Examples of the C5 fraction and the C9 fraction include the petroleum fractions mentioned above. As the C5C9 resin, for example, commercially available resins from Tosoh Corporation, LUHUA Corporation, etc. can be used.

[0148] The acrylic resin is not particularly limited, and for example, a solventless acrylic resin can be used.

[0149] Examples of solvent-free acrylic resins include (meth)acrylic resins (polymers) synthesized by high-temperature continuous polymerization (high-temperature continuous bulk polymerization) (methods described in U.S. Pat. No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Pat. No. 5,010,166, and Toa Gosei Kenkyusho Annual Report TREND 2000 Vol. 3, pp. 42-45, etc.), with minimal use of secondary raw materials such as polymerization initiators, chain transfer agents, and organic solvents. In this disclosure, (meth)acrylic refers to both methacrylic and acrylic.

[0150] 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.

[0151] Furthermore, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or a (meth)acrylic acid derivative as a monomer component constituting the acrylic resin.

[0152] The acrylic resin may be a resin composed only of a (meth)acrylic component, or a resin containing components other than a (meth)acrylic component, and may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0153] As the resin component, for example, products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Clayton, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., Taoka Chemical Co., Ltd., and the like can be used.

[0154] (c) Lubricant (Stearic Acid) The rubber composition may contain a lubricant. As the lubricant, a lubricant based on a fatty acid derivative such as stearic acid can be preferably used. As the stearic acid, a conventionally known lubricant can be used, and specifically, for example, products from NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc. can be used. In addition, Struktol WB16 manufactured by Struktol Co., Ltd. can also be used.

[0155] The amount of stearic acid per 100 parts by mass of the rubber component is, for example, preferably more than 0.5 parts by mass and less than 10.0 parts by mass.

[0156] (D) Antiaging Agent 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 per 100 parts by mass of the rubber component.

[0157] 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; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, and N,N'-di-2-naphthyl-p-phenylenediamine. p-phenylenediamine-based antioxidants such as quinolinol; 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; and bis-, tris-, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. These antioxidants may be used alone or in combination of two or more.

[0158] Specific examples of antioxidants that can be used include products from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis, and the like.

[0159] (e) Zinc Oxide The rubber composition may contain zinc oxide. The content of zinc oxide is, for example, more than 0.5 parts by mass and less than 10 parts by mass per 100 parts by mass of the rubber component. As the zinc oxide, a conventionally known product can be used, and for example, products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0160] (F) Wax The rubber composition may contain wax. The content of the wax relative to 100 parts by mass of the rubber component is, for example, preferably 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, and even more preferably 1.5 to 10 parts by mass.

[0161] The wax is not particularly limited, and examples thereof include petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as vegetable wax and animal wax; and synthetic waxes such as polymers of ethylene, propylene, etc. These may be used alone or in combination of two or more.

[0162] As the wax, for example, products from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Seiko Chemical Co., Ltd., etc. can be used.

[0163] (G) 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 parts by mass and less than 10.0 parts by mass per 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 oil content.

[0164] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. These may be used alone or in combination of two or more.

[0165] As sulfur, for example, products from Tsurumi Chemical Industry Co., Ltd., Karuizawa Iso Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0166] Crosslinking agents other than sulfur may also be used. Specifically, for example, vulcanizing agents containing sulfur atoms such as TACKIROL V200 manufactured by Taoka Chemical Co., Ltd., DURALINK HTS (1,6-hexamethylene-sodium dithiosulfate dihydrate) manufactured by Flexis, and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane: hybrid crosslinking agent) manufactured by LANXESS, and organic peroxides such as dicumyl peroxide can be used.

[0167] The rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator per 100 parts by mass of the rubber component is, for example, more than 0.3 parts by mass and less than 10.0 parts by mass.

[0168] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-t-butyl-2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenyl guanidine, di-orthotolyl guanidine, and orthotolyl biguanidine. These may be used alone or in combination of two or more.

[0169] (H) Others In addition to the above-mentioned components, the rubber composition may contain additives commonly used in the tire industry, such as organic fillers such as cellulose fibers, organic peroxides, etc. The content of these additives is, for example, more than 0.1 parts by mass and less than 50 parts by mass per 100 parts by mass of the rubber component.

[0170] (2) Preparation of Rubber Composition The rubber composition can be prepared by a general method, for example, a production method including a base kneading step of kneading a rubber component with a filler such as carbon black, and a finish kneading step of kneading the kneaded product obtained in the base kneading step with a crosslinking agent.

[0171] The kneading can be carried out using a known (internal) kneading machine such as a Banbury mixer, a kneader, or an open roll.

[0172] The kneading temperature in the base kneading step is, for example, higher than 50° C. and lower than 200° C., and the kneading time is, for example, higher than 30 seconds and lower than 30 minutes. In the base kneading step, in addition to the above components, compounding agents conventionally used in the rubber industry, for example, softeners such as oil, stearic acid, zinc oxide, antioxidants, waxes, vulcanization accelerators, etc., may be appropriately added and kneaded as needed.

[0173] In the final kneading step, the kneaded product obtained in the base kneading step is kneaded with a crosslinking agent. The kneading temperature in the final kneading step is, for example, higher than room temperature and lower than 80°C, and the kneading time is, for example, longer than 1 minute and shorter than 15 minutes. In the final kneading step, in addition to the above components, a vulcanization accelerator, zinc oxide, etc. may be appropriately added and kneaded as necessary.

[0174] The rubber composition obtained as described above can then be extruded into a predetermined shape to form a tread.

[0175] 2. Tire Manufacturing The tire according to the present embodiment can be manufactured by a conventional method. First, the rubber composition obtained as described above is molded into a predetermined shape to manufacture a tread. Next, the rubber composition is combined with other rubber components on a tire building machine to manufacture an unvulcanized tire.

[0176] Specifically, an inner liner as a component for ensuring the airtightness of the tire, a carcass as a component for withstanding the load, impact, and inflation pressure to which the tire is subjected, and a belt component as a component for tightly fastening the carcass and increasing the rigidity of the tread are wound around a forming drum, and both ends of the carcass are fixed to both side edges, and bead portions as components for fixing the tire to the rim are arranged. After forming into a toroidal shape, a tread is attached to the center of the outer periphery and sidewalls are attached to the radially outer sides to form side portions, thereby producing an unvulcanized tire.

[0177] The unvulcanized tire thus produced is then heated and pressurized in a vulcanizer to obtain a tire. The vulcanization step can be carried out by applying a known vulcanization method. The vulcanization temperature is, for example, higher than 120°C and lower than 200°C, and the vulcanization time is, for example, longer than 5 minutes and shorter than 15 minutes.

[0178] As described above, the tire obtained as described above can achieve improved overall performance in terms of wet grip performance and wear resistance due to the combined effect of the appropriately formed twisted sipes and the effect of the appropriate content of reinforcing filler.

[0179] The tires according to the present disclosure can be suitably used as passenger car tires, large passenger car tires, large SUV tires, truck and bus tires, motorcycle tires, racing tires, studless tires (winter tires), all-season tires, run-flat tires, etc., and are particularly preferably used as passenger car tires.

[0180] Below, examples (embodiments) that are considered preferable for implementation will be shown, but the scope of the present invention is not limited to these examples.

[0181] Tables 1 and 2 show the results of calculations based on the following evaluation method assuming a tire (tire size 175 / 60R18: aspect ratio 60%) made of a tread molded from the various compounded materials shown below and other rubber components.

[0182] 1. Preparation of Rubber Composition A rubber composition for tread is prepared using the various compounding materials shown below.

[0183] (1) Compounding Materials (a) Rubber Component (a) NR: TSR20 (b) SBR: HPR840 (S-SBR) manufactured by ENEOS Materials Corporation (styrene content: 10% by mass, vinyl content: 42% by mass) (c) BR: Ubepol BR150B (high cis BR) manufactured by Ube Industries, Ltd. (cis content: 97% by mass, trans content: 2% by mass, vinyl content: 1% by mass)

[0184] (b) Compounding materials other than rubber components (a) Carbon black: Diablack N220 (N) manufactured by Mitsubishi Chemical Corporation ２ SA: 115m ２ / g) (b) Silica: Ultrasil VN3 (N) manufactured by Evonik Industries ２ SA: 175m ２ / g, average primary particle size: 17 nm) (c) Silane coupling agent: NXT (3-octanoylthiopropyltriethoxysilane) manufactured by Momentive Corporation (d) Oil: Process oil A / OMIX manufactured by Sankyo Yuka Kogyo Co., Ltd. (e) Resin: YS Resin PX850 manufactured by Yasuhara Chemical Co., Ltd. (softening point 85°C, β-pinene resin (terpene resin)) (f) Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. (g) Antioxidant-1: Nocrac 6C (N-(1,3 dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (h) Antioxidant-2: Nocrac RD (poly(2,2,4-trimethyl-1,2-dihydroquinoline)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (i) Stearic acid: Beaded stearic acid "Tsubaki" manufactured by NOF Corporation (j) Zinc oxide: Zinc oxide type 2 manufactured by Mitsui Mining & Smelting Co., Ltd. (k) Sulfur: Powdered sulfur manufactured by Karuizawa Iso Co., Ltd. (l) Accelerator-1: Noccela CZ-G (CBS) (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (m) Accelerator-2: Noccela D (DPG) (1,3-diphenylguanidine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0185] (2) Preparation of Rubber Composition for Tread Based on each formulation shown in Tables 1 and 2, materials other than sulfur and vulcanization accelerator are kneaded for 5 minutes under the condition of 150°C using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded mixture.

[0186] Next, sulfur and a vulcanization accelerator are added to the kneaded mixture, and the mixture is kneaded for 5 minutes at 80° C. using an open roll to obtain each rubber composition for tread.

[0187] 2. Tread Molding Next, the rubber composition obtained above is molded into a tread provided with twisted sipes having the specifications shown in Tables 1 and 2. The size of the sipes is 0.6 mm wide x 10 mm long (= total opening area A: 6.0 mm). ２ ) x depth 6.0 mm.

[0188] 3. Tire Manufacturing Next, the tread obtained above was laminated together with other tire components to form an unvulcanized tire, which was then press-vulcanized at 170°C for 10 minutes to manufacture test tires for each of the Examples and Comparative Examples.

[0189] 4. Performance Evaluation Test Performance evaluation tests are conducted to evaluate wear resistance and wet grip performance, and a comprehensive performance evaluation is then conducted based on the results of both evaluations.

[0190] (1) Wear Resistance Performance Evaluation Each test tire was fitted to all wheels of a vehicle (a domestically produced FF vehicle with an engine displacement of 2000cc), and the tires were inflated to an internal pressure of 230 kPa. The vehicle was then driven 50,000 km on a test course with a dry asphalt surface that replicated a public road. The wear resistance performance was evaluated by comparing the amount of wear in the tread portion before and after the run. Specifically, the result of Comparative Example 1 was set to 100, and the result was indexed according to the following formula to evaluate the wear resistance performance. The larger the value, the smaller the amount of wear and the better the wear resistance. Wear resistance performance = [(Results of Comparative Example 1) / (Results of test tire)] x 100

[0191] (2) Evaluation of Wet Grip Performance Each test tire was mounted on all wheels of a vehicle (a domestically produced FF vehicle with an engine displacement of 2000 cc) and inflated to an internal pressure of 230 kPa. After that, the braking distance from an initial speed of 100 km / h on a wet road surface was measured.

[0192] Next, the braking distance obtained in Comparative Example 1 was set as 100, and indexed according to the following formula to evaluate wet grip performance. A larger value indicates better wet grip performance. Wet grip performance = [(Result of Comparative Example 1) / (Result of test tire)] x 100

[0193] (3) Overall Performance Evaluation The results of the wear resistance performance evaluation and the wet grip performance evaluation are then added together to obtain an overall performance evaluation.

[0194]

[0195]

[0196] Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments. Various modifications can be made to the above-described embodiments within the scope of the same or equivalent to the present invention.

[0197] The present invention (1) is a tire having a tread portion, wherein a land portion of the tread portion has a groove having a width of 2 mm or less and a depth of 20 mm or less, which groove has a twisted shape when viewed in a plane from the surface of the tread portion, and two or more intersections where an opening of the groove intersects with a groove bottom of the groove are formed in the longitudinal direction and spaced apart from each other, the total area of ​​the intersections is 95% or less of the area of ​​the opening when viewed in a plane from the surface of the tread portion, the tread portion is formed from a rubber composition containing a rubber component and 20 parts by mass or more of a reinforcing filler per 100 parts by mass of the rubber component, and further wherein, when the number of intersections per groove is X (number of intersections) and the content of the reinforcing filler is Y (parts by mass), X×Y>100.

[0198] The present invention (2) is the tire according to the present invention (1), characterized in that the total area of ​​the intersections is 90% or less of the area of ​​the openings when viewed in plan from the surface of the tread portion.

[0199] The present invention (3) is the tire according to the present invention (2), characterized in that the total area of ​​the intersections is 70% or less of the area of ​​the openings when viewed in plan from the surface of the tread portion.

[0200] The present invention (4) is characterized in that the total area of ​​the intersections is 10% or more of the area of ​​the openings when viewed in plan from the surface of the tread portion, and is a tire in any combination with any of the present inventions (1) to (3).

[0201] The present invention (5) is characterized in that the content Y of the reinforcing filler is more than 40 parts by mass per 100 parts by mass of the rubber component, and is a tire in any combination with any of the present inventions (1) to (4).

[0202] A sixth aspect of the present invention is the tire according to the fifth aspect of the present invention, characterized in that the content Y of the reinforcing filler is less than 180 parts by mass per 100 parts by mass of the rubber component.

[0203] The present invention (7) is characterized in that the number X of intersections per groove is 3 or more, and is a tire in any combination with any of the present inventions (1) to (6).

[0204] The present invention (8) is the tire according to the present invention (7), characterized in that the number X of the intersections per groove is 10 or less.

[0205] The present invention (9) is characterized in that X×Y is greater than 130, and is a tire in any combination with any of the present inventions (1) to (8).

[0206] The present invention (10) is the tire according to the present invention (9), characterized in that X×Y is greater than 160.

[0207] The present invention (11) is a tire characterized in that X×Y is less than 500, and is an arbitrary combination with any of the present inventions (1) to (10).

[0208] The present invention (12) is a tire characterized in that the width of the opening is less than 1.8 mm, and is any combination with any of the present inventions (1) to (11).

[0209] The present invention (13) is a tire characterized in that the groove depth is less than 15 mm, and is an optional combination with any of the present inventions (1) to (12).

[0210] The present invention (14) is a tire characterized by containing silica as the reinforcing filler, and is any combination with any of the present inventions (1) to (13).

[0211] The present invention (15) is the tire according to the present invention (14), characterized in that the content of silica per 100 parts by mass of the rubber component is more than 70 parts by mass.

[0212] The present invention (16) is the tire according to the present invention (15), characterized in that the average particle size of the silica is less than 25 nm.

[0213] The present invention (17) is characterized in that the content of styrene-butadiene rubber is 20 parts by mass or more, the content of isoprene-based rubber is 20 parts by mass or more, and the content of butyl rubber is 5 parts by mass or more, relative to 100 parts by mass of the rubber component, and is a tire in any combination with any of the present inventions (1) to (16).

[0214] 1 Land portion 2 Groove (twisted sipe) 2t Opening 2b Groove bottom S1 to S4 Intersection

Claims

1. A tire having a tread portion, wherein grooves having a width of 2 mm or less and a depth of 20 mm or less are formed in the land portion of the tread portion, and when viewed in a plane from the surface of the tread portion, the grooves have a twisted shape, and two or more intersections where the openings of the grooves intersect with the bottoms of the grooves are formed in the longitudinal direction and spaced apart from one another; the total area of ​​the intersections is 95% or less of the area of ​​the openings when viewed in a plane from the surface of the tread portion; the tread portion is formed from a rubber composition containing a rubber component and 20 parts by mass or more of a reinforcing filler per 100 parts by mass of the rubber component; and further wherein, when the number of intersections per groove is X (number of intersections) and the content of the reinforcing filler is Y (parts by mass), X x Y > 100.

2. The tire according to claim 1, wherein the total area of ​​the intersections is 90% or less of the area of ​​the openings when viewed in plan from the surface of the tread portion.

3. The tire according to claim 2, wherein the total area of ​​the intersections is 70% or less of the area of ​​the openings when viewed in plan from the surface of the tread portion.

4. A tire according to any one of claims 1 to 3, characterized in that the total area of ​​the intersections is 10% or more of the area of ​​the openings when viewed in plan from the surface of the tread portion.

5. The tire according to any one of claims 1 to 4, wherein the content Y of the reinforcing filler is more than 40 parts by mass per 100 parts by mass of the rubber component.

6. The tire according to claim 5, wherein the content Y of the reinforcing filler is less than 180 parts by mass per 100 parts by mass of the rubber component.

7. A tire according to any one of claims 1 to 6, characterized in that the number X of intersections per groove is three or more.

8. The tire according to claim 7, wherein the number X of intersections per groove is 10 or less.

9. A tire according to any one of claims 1 to 8, characterized in that X x Y is greater than 130.

10. The tire according to claim 9, wherein said X x Y is greater than 160.

11. A tire according to any one of claims 1 to 10, wherein X x Y is less than 500.

12. A tire according to any one of claims 1 to 11, characterized in that the width of the opening is less than 1.8 mm.

13. A tire according to any one of claims 1 to 12, characterized in that the groove depth is less than 15 mm.

14. A tire according to any one of claims 1 to 13, characterized in that the reinforcing filler is silica.

15. The tire according to claim 14, wherein the content of silica per 100 parts by mass of the rubber component is more than 70 parts by mass.

16. The tire according to claim 15, wherein the average particle size of said silica is less than 25 nm.

17. A tire described in any one of claims 1 to 16, characterized in that the content of styrene butadiene rubber is 20 parts by mass or more, the content of isoprene-based rubber is 20 parts by mass or more, and the content of butyl rubber is 5 parts by mass or more per 100 parts by mass of the rubber component.

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