Tire

Abstract

The invention provides a tire capable of improving the comprehensive performance of low fuel consumption and high-speed durability. A tire is provided with: a carcass provided with carcass cords; a belt layer provided with belt layer cords and provided on the outside of the carcass in the tire radial direction; a cap ply provided with a cap ply cord and provided on the outside of the belt layer in the tire radial direction; and a tread provided on the outside of the cap ply in the radial direction of the tire, in which the cap ply cords contain polyethylene terephthalate fibers, the ratio of the tire weight (kg) to the maximum bearing capacity (kg) of the tire (tire weight / maximum bearing capacity) being less than 0.014, and the ratio of the tire weight (kg) to the maximum bearing capacity (kg) of the tire being less than 0.014. The product of the tire weight (kg) and the diameter (mm) of the cap ply cord (tire weight * the diameter of the cap ply cord) is less than 4.3.

Description

Technical Field

[0001] The present invention relates to a tire. Background Art

[0002] As described in Patent Document 1, in a passenger car tire, from the aspect of preventing tire deformation caused by centrifugal force generated during high-speed driving and improving high-speed durability, a crown belt layer is usually provided between the tread and the belt layer.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-38812 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The problem of the present invention is to achieve an improvement in the comprehensive performance of low fuel consumption and high-speed durability.

[0008] Means for Solving the Problems

[0009] The present invention relates to a tire having:

[0010] A carcass having carcass cords;

[0011] A belt layer having belt layer cords and provided radially outside the carcass of the tire;

[0012] A crown belt layer having crown belt layer cords and provided radially outside the belt layer of the tire; and

[0013] A tread provided radially outside the crown belt layer of the tire,

[0014] The tire is characterized in that

[0015] The crown belt layer cords contain polyethylene terephthalate fibers,

[0016] The ratio (tire weight / maximum load capacity) of the tire weight (kg) to the maximum load capacity (kg) of the tire is less than 0.014,

[0017] The product (tire weight × crown belt layer cord diameter) of the tire weight (kg) and the diameter (mm) of the crown belt layer cords is less than 4.3.

[0018] Advantages of the Invention

[0019] According to the present invention, it is possible to achieve an improvement in the comprehensive performance of low fuel consumption and high-speed durability. Brief Description of the Drawings

[0020] Figure 1 It is a schematic cross-sectional view of a tire illustrating an embodiment of the present invention. Detailed Embodiment

[0021] [1] Features of the tire of the present invention

[0022] First, the features of the tire of the present invention will be described.

[0023] 1. Outline

[0024] The tire of the present invention includes: a carcass having carcass cords; a belt layer having belt layer cords and disposed on the radially outer side of the carcass in the tire; a cap ply having cap ply cords and disposed on the radially outer side of the belt layer in the tire; and a tread disposed on the radially outer side of the cap ply in the tire. Further, the cap ply cords include polyethylene terephthalate fibers (PET fibers). In addition, the ratio (tire weight / maximum load capacity) of the tire weight (kg) to the maximum load capacity (kg) of the tire is less than 0.014. Moreover, the product (tire weight × diameter of cap ply cords) of the tire weight (kg) and the diameter (mm) of the cap ply cords is less than 4.3.

[0025] It should be noted that in this specification, regarding the "diameter of the cords", it refers to the diameter when the circumscribed circle of the cross-section perpendicular to the cord extending direction is a perfect circle, and in the case of an ellipse or the like, it refers to the equivalent circle diameter (the diameter of the circle assuming the same cross-sectional area).

[0026] By having these features, as described later, it is possible to improve the comprehensive performance of low fuel consumption and high-speed durability.

[0027] 2. Mechanism of effect manifestation in the tire of the present invention

[0028] Regarding the mechanism of the above effect manifestation in the tire of the present invention, the following can be considered.

[0029] PET fibers are lighter than nylon 66 (polyamide synthetic fibers), so it is considered that by using cap ply cords containing PET fibers, it is possible to achieve weight reduction of the tire. In addition, PET fibers have a higher modulus (higher rigidity) than nylon 66 (polyamide synthetic fibers), so it is considered that by using cap ply cords containing PET fibers, it is possible to suppress tire deformation (change in the contact shape) during driving and achieve high-speed durability.

[0030] The present inventors have conducted research and found that when the ratio of the tire weight (kg) to the maximum load-carrying capacity of the tire (kg) (tire weight / maximum load-carrying capacity) is controlled to be less than 0.014, and the product of the tire weight (kg) and the diameter (mm) of the cap ply cord (tire weight × cap ply cord diameter) is controlled to be less than 4.3, an improvement in the comprehensive performance of low fuel consumption and high-speed durability of the tire can be achieved.

[0031] It should be noted that (tire weight / maximum load-carrying capacity) is more preferably less than 0.013, further preferably less than 0.012, further preferably less than 0.011, and further preferably less than 0.010. As the lower limit, there is no particular limitation. For example, it is preferably more than 0.003, more preferably more than 0.005, and further preferably more than 0.007.

[0032] In addition, (tire weight × cap ply cord diameter) is more preferably less than 4.0, further preferably less than 3.5, and further preferably less than 3.0. As the lower limit, there is no particular limitation. For example, it is preferably more than 1.5, more preferably more than 2.0, and further preferably more than 2.5. It should be noted that the tire weight can be reduced by methods such as reducing the fineness of various cords constituting the tire, thinning the thickness of the tread or sidewall, or reducing the density of the rubber composition of various components used to form the tire.

[0033] [2] More preferred embodiments of the tire of the present invention

[0034] The tire of the present invention can achieve greater effects by adopting the following methods.

[0035] 1. Belt layer

[0036] The belt layer can be 1 layer, 2 layers, or 3 or more layers. The material of the filaments constituting the belt layer is preferably a metal, more preferably iron (steel). The cross-section of the filaments constituting the belt layer can be circular or elliptical, preferably circular. In addition, it can be corrugated or treated by plating. As the structure of the belt layer cord, it can be a structure without twisting the filaments, can be single-twist (1×2, 1×3, 1×4), or can be layer-twist (2+2). In the case of a 1×1 structure, it is preferred to make a cord from 1 filament in a non-twisted and non-corrugated manner.

[0037] As the belt layer cord, a steel cord with high rigidity can preferably be used. At this time, the number of filaments of the steel cord is preferably 1 or more and 4 or less. Since the belt layer cord accounts for a high proportion of the tire weight, by reducing the number of filaments to 4 or less, the belt layer cord can be further lightened, achieving further lightening of the tire. More preferably, it is 2 or more and 3 or less.

[0038] It should be noted that as the structure of the belt cord, any one of a 1×1 structure, a 1×2 structure, a 1×3 structure, a 1×4 structure, and a 2+2 structure is preferred.

[0039] However, the binding force of the lightweight belt cord is reduced, which may lead to a reduction in high-speed durability.

[0040] Therefore, in the present invention, when the tire is viewed from the radially outer side, the crossing angle (crossing angle B) of the belt cord with respect to the equatorial plane is preferably less than 25 degrees. In this way, by controlling the crossing angle B to be small, the binding force can be maintained, so it is considered that the reduction in high-speed durability will not be caused, and further improvement can be achieved.

[0041] 2. Crowned belt layer

[0042] The crowned belt layer can be 1 layer or 2 layers. The crowned belt layer can be formed in the entire width direction of the tread, or can be formed only at both ends of the tread. It is preferred to have both a crowned belt layer formed in the entire width direction of the tread and a crowned belt layer formed only at both ends of the tread.

[0043] The crowned belt cord can be composed of fibers such as polyester fibers. As the fibers constituting the crowned belt cord, PET (polyethylene terephthalate) fibers and PEN (polyethylene naphthalate) fibers in polyester fibers are preferred, and PET fibers are more preferred. In addition, the fibers constituting the crowned belt cord can be fibers recycled from used products or waste products (recycled materials), or can be fibers synthesized from biomass (biomass materials). Furthermore, the crowned belt cord can also be a mixed cord combining PET fibers with other fibers (such as aramid fibers).

[0044] As described above, in the present invention, when the crowned belt cord contains PET fibers, it is preferably a PET cord composed of a single twist formed by twisting one yarn. Thereby, while maintaining a high binding force, the cord thickness can be reduced, so it is considered that further low fuel consumption of the tire can be achieved.

[0045] It should be noted that the diameter of the crowned belt cord measured according to the method specified in JIS L1017:2002 is preferably 0.2 mm or more, more preferably 0.3 mm or more. As the upper limit, it is preferably 0.8 mm or less, more preferably 0.6 mm or less.

[0046] After treating the crowned belt cord with an adhesive and bonding it to a specified rubber composition for the crowned belt layer, the crowned belt layer can be formed. It should be noted that as the adhesive used in the bonding, for example, EX-313 (glycerol polyglycidyl ether, manufactured by Nagase chemteX Corporation) and RFL (resorcinol-formaldehyde-emulsion) as epoxy compounds can be used.

[0047] It should be noted that as the PET fiber, it can be a sustainable PET fiber, that is, a PET fiber (recycled PET fiber) obtained by recycling used plastic bottles and other plastic wastes (used products or waste materials). In addition, it can also be a PET fiber (biomass PET fiber) obtained by using biomass as a raw material. From the aspect of environmental protection, it is suitable to use such sustainable PET fibers.

[0048] 3. Carcass

[0049] The carcass can be 1 layer or 2 layers, and preferably 1 layer. The carcass cord can be composed of fibers. As the fibers constituting the carcass cord, conventionally known fibers can be used, such as polyester fibers such as PET (polyethylene terephthalate) fiber and PEN (polyethylene naphthalate) fiber, polyamide fibers such as nylon 6 fiber and nylon 66 fiber, and aromatic polyamide fibers. Two or more kinds of fibers can be used in combination to make a hybrid cord. The fibers constituting the carcass cord can be fibers recycled from used products or waste products (recycled materials), or can be fibers synthesized from biomass (biomass materials).

[0050] In the present invention, the carcass cord preferably contains fibers with a fineness exceeding 2400 dtex. In the case of a carcass cord with a low total fineness, it is necessary to form the carcass with two or more layers of the cord. However, in the case of using a carcass cord with a high total fineness exceeding 2400 dtex, the carcass can be formed by one layer of the cord. Therefore, the amount of rubber between the layers can be further reduced, and it is considered that further weight reduction of the tire can be achieved. More preferably, it is 3000 dtex or more, and further preferably 4000 dtex or more. As the upper limit, it is preferably 5000 dtex or less, more preferably 4800 tex or less, and further preferably 4600 dtex or less.

[0051] 4. Silica

[0052] In the present invention, in the rubber composition constituting the tread (tread rubber composition), preferably more than 75 parts by mass of silica is contained relative to 100 parts by mass of the rubber component. Silica is a reinforcing filler, which can harden the tread and suppress a large change in the tread profile during high-speed driving. Therefore, it is considered that further improvement in high-speed durability can be achieved. In addition, since silica has OH groups on its surface and can capture ozone, the ozone resistance is improved. From this aspect, it is also considered that further improvement in high-speed durability can be achieved. More preferably, it is 80 parts by mass or more, and further preferably 90 parts by mass or more. As the upper limit, for example, it is preferably 150 parts by mass or less, and more preferably 100 parts by mass or less.

[0053] At this time, if the particle size (average primary particle size) of silica is too small, the processability deteriorates. Therefore, it is preferable to use silica with a particle size exceeding 8 nm, more preferably 9 nm or more, and still more preferably 10 nm or more. On the other hand, from the aspect of ensuring the reinforcement of rubber, it is preferably 25 nm or less, more preferably 20 nm or less, and still more preferably 17 nm or less.

[0054] It should be noted that 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 aggregated structure as a circle and measuring the absolute maximum length of the smallest particle as the diameter of the circle. It can be observed by a transmission or scanning electron microscope. More than 400 primary particles of silica observed in the field of view are measured, and the average value is obtained from them.

[0055] Specifically, silica taken out from the rubber composition cut out from a tire is directly observed using an electron microscope or the like, the equivalent cross-sectional diameter is calculated from the area of each silica particle obtained, and the average value is obtained, whereby the average primary particle size can be calculated.

[0056] 5. Acetone extract component (AE amount)

[0057] In the present invention, the acetone extract component (AE amount) of the tread rubber composition is preferably more than 15% by mass, more preferably 17% by mass or more. On the other hand, as the upper limit, for example, it is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, and particularly preferably 25% by mass or less.

[0058] The acetone extract component (AE amount) can be considered as an index indicating the amount of materials such as softeners (plasticizers) that impart plasticity to the rubber component in the rubber composition, and can also be considered as an index indicating the softness of the rubber composition. Therefore, when the AE amount of the tread rubber composition is increased to a certain extent, the tread blocks can be deformed softly, and even when driving at high speed, the contact area with the road surface can be sufficiently ensured, and heat generation due to the concentration of contact pressure can be suppressed. Therefore, it is considered that a further improvement in high-speed durability can be achieved.

[0059] It should be noted that the measurement of the acetone extract component (AE amount) can be carried out in accordance with JIS K 6229:2015. Specifically, a vulcanized rubber test piece cut out from the measurement part is immersed in acetone for a specified time, and the mass reduction rate (%) of the test piece is obtained, whereby the AE amount (mass%) can be obtained.

[0060] More specifically, each vulcanized rubber test piece is immersed in acetone for 72 hours at normal temperature and normal pressure to extract the soluble components, and the mass of each test piece before and after extraction is measured, and it can be obtained by the following formula.

[0061] Acetone extraction amount (%) = { (Mass of rubber test piece before extraction - Mass of rubber test piece after extraction) / (Mass of rubber test piece before extraction)} × 100

[0062] In addition, the above-mentioned acetone extraction components can be appropriately changed by changing the blending ratio of the plasticizer in the rubber composition.

[0063] [3] Embodiment

[0064] Hereinafter, the present invention will be specifically described based on the embodiment.

[0065] 1. Tire of the present embodiment

[0066] Figure 1 is a schematic cross-sectional view showing the tire of the present embodiment. Figure 1 In, the up-down direction is the radial direction of the tire, the left-right direction is the rotation axis direction of the tire, and the direction perpendicular to the paper surface is the circumferential direction of the tire. It should be noted that Figure 1 in, the dotted line CL represents the equatorial plane of the tire. It should be noted that the shape of this tire is symmetric with respect to the equatorial plane except for the tread pattern, so Figure 1 1 / 4 of the entire tire is shown in.

[0067] As Figure 1 shown, the tire 1 includes a tread 2, a pair of sidewalls 3, a pair of chafing parts 4, a pair of beads 5, an inner liner 6, a carcass 7, a belt layer 8, a pair of fillers 9, and a cap ply 10. The carcass 7, the belt layer 8, the cap ply 10, and the tread 2 are arranged from the inner side to the outer side in the radial direction of the tire. Here, the cap ply 10 includes cap ply cords containing PET fibers. It should be noted that Figure 1 in, the tread 2 is composed of 1 layer, or may be composed of 2 or more layers by providing a crown rubber layer on the outer side and a base rubber layer on the inner side, or may be composed of 3 or more layers. The upper limit of the thickness of the tread is preferably 20 mm or less, more preferably 15 mm or less.

[0068] With such a configuration, as described above, (tire weight / maximum load capacity) and (tire weight × diameter of cap ply cords) are appropriately controlled, thereby enabling improvement in the comprehensive performance of low fuel consumption and high-speed durability.

[0069] 2. Rubber composition for tread

[0070] In the present embodiment, the rubber composition for tread can be obtained by kneading various blending materials such as rubber components, reinforcing materials, anti-aging agents, oils, resin materials, and anti-aging agents.

[0071] (1) Blending materials

[0072] (a) Rubber component

[0073] The rubber component is not particularly limited, and for example, isoprene-based rubbers (natural rubber (NR), isoprene rubber (IR), etc.), styrene-butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR) and other diene-based rubbers can be used. They can be used alone or in combination of two or more. In the present invention, the combination of NR, SBR and BR is preferred.

[0074] (①) SBR

[0075] The weight average molecular weight of SBR is, for example, more than 100,000 and less than 2,000,000. The styrene content of SBR is, for example, preferably more than 5% by mass, more preferably more than 10% by mass, and further preferably more than 15% by mass. On the other hand, it is preferably less than 40% by mass, more preferably less than 35% by mass, and further preferably less than 30% by mass. The vinyl content (the amount of 1,2-bonded butadiene units) of SBR is, for example, preferably more than 5% by mass, more preferably more than 10% by mass, and further 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 further preferably less than 30% by mass. It should be noted that the structural identification (measurement of styrene content and vinyl content) of SBR can be carried out, for example, using a device of the JNM-ECA series manufactured by JEOL Ltd.

[0076] SBR is not particularly limited, and for example, emulsion polymerization styrene-butadiene rubber (E-SBR), solution polymerization styrene-butadiene rubber (S-SBR), etc. can be used. SBR can be either unmodified SBR or modified SBR. In addition, hydrogenated SBR obtained by hydrogenating the butadiene part in SBR can be used, and the hydrogenated SBR can also be obtained by subsequently hydrogenating the BR part in SBR, or the same structure can be obtained by copolymerizing styrene, ethylene and butadiene.

[0077] As the modified SBR, SBR having a functional group that interacts with a filler such as silica is preferred. For example, there can be mentioned end-modified SBR obtained by modifying at least one end of SBR with a compound (modifying agent) having the above functional group (end-modified SBR having the above functional group at the end); main-chain modified SBR having the above functional group in the main chain; main-chain end-modified SBR having the above functional group in the main chain and at the end (for example, main-chain end-modified SBR having the above functional group in the main chain and modifying at least one end with the above modifying agent); end-modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and introducing hydroxyl groups, epoxy groups, etc.

[0078] Examples of the above functional groups include, for example, amino group, amide group, silyl group, alkoxysilyl group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, mercapto group, thioether group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazine group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group, etc. It should be noted that these functional groups may have substituents.

[0079] In addition, as the modified SBR, for example, SBR modified with a compound (modifier) represented by the following formula can be used.

[0080] [Chemical Formula 1]

[0081]

[0082] It should be noted that in the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silanyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R 4 and R 5 may be bonded to form a ring structure together with the nitrogen atom. n represents an integer.

[0083] As the modified SBR modified with the compound (modifier) represented by the above formula, SBR obtained by modifying the polymerization terminal (active terminal) of solution-polymerized styrene-butadiene rubber (S-SBR) with the compound represented by the above formula (modified SBR described in Japanese Patent Laid-Open No. 2010-111753, etc.) can be used.

[0084] As R 1 , R 2 and R 3 , an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms) is suitable. As R 4 and R 5 , an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms) is suitable. n is preferably 1 to 5, more preferably 2 to 4, and further preferably 3. In addition, when R 4 and R 5 are bonded to form a ring structure together with the nitrogen atom, a 4- to 8-membered ring is preferred. It should be noted that the alkoxy group also includes cycloalkoxy groups (such as cyclohexyloxy group) and aryloxy groups (such as phenoxy group, benzyloxy group).

[0085] Specific examples of the above-mentioned modifiers include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. They can be used alone or in combination of two or more.

[0086] In addition, as the modified SBR, a modified SBR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxides 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, diglycidyl-o-toluidine, tetraglycidyl-m-xylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bis(aminomethyl)cyclohexane and other diglycidylamino compounds; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamoyl chloride, N,N-diethylcarbamoyl chloride; epoxy group-containing silane compounds such as 1,3-bis(epoxypropylpropyl)-tetramethyldisiloxane and (3-epoxypropylpropyl)-pentamethyldisiloxane; thioether group-containing silane compounds such as (trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide; N-substituted aziridine compounds such as aziridine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltriethoxysilane;(Thio)benzophenone compounds having amino groups and / or substituted amino groups such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-tert-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; Benzaldehyde compounds having amino groups and / or substituted amino groups such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone; N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; and N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tri-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylvinylurea, 1,3-divinylvinylurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-acetone, 1,7-bis(methylethylamino)-4-heptanone, etc. It should be noted that the modification by the above compounds (modifiers) can be carried out by known methods.;

[0087] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., ENEOS Materials Co., Ltd., Asahi Kasei Corporation, Zeon Corporation, etc. can be used. It should be noted that the SBR can be used alone or in combination of two or more kinds.

[0088] The content of SBR in 100 parts by mass of the rubber component is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, and further preferably 50 parts by mass or more. As the upper limit, for example, it is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and further preferably 60 parts by mass or less.

[0089] (②) Isoprene rubber

[0090] As the isoprene rubber, natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, etc. can be mentioned. From the aspect of excellent strength, NR is preferred.

[0091] As the NR, for example, SVR-L, SIR20, RSS#3, TSR20, etc., which are commonly used in the tire industry, can be used. As the IR, there is no particular limitation, and for example, IR2200 manufactured by Zeon Corporation can be used, which is commonly used in the tire industry. As the modified NR, deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. can be mentioned. As the modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. can be mentioned. As the modified IR, epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. can be mentioned. They can be used alone or in combination of two or more.

[0092] The content of the isoprene rubber in 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more. As the upper limit, for example, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less.

[0093] (③) BR

[0094] The weight-average molecular weight of BR is, for example, more than 100,000 and less than 2 million. The vinyl content of BR is, for example, more than 1% and less than 30%. The cis content of BR is, for example, more than 1% and 98% or less. The trans content of BR is, for example, more than 1% and less than 60%. It should be noted that the cis content can be measured by infrared absorption spectrometry.

[0095] There is no particular limitation for BR, and BR with a high cis content (cis content of 90% or more), BR with a low cis content, BR containing syndiotactic polybutadiene crystals, etc. can be used. BR can be either unmodified BR or modified BR. As the modified BR, for example, BR modified with a compound (modifying agent) represented by the following formula can be used.

[0096] [Chemical formula 2]

[0097]

[0098] It should be noted that in the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silanyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R4 and R 5 can be bonded to form a ring structure together with a nitrogen atom. n represents an integer.

[0099] As the modified BR modified with the compound (modifier) represented by the above formula, BR obtained by modifying the polymerization terminal (active terminal) with the compound represented by the above formula can be mentioned.

[0100] As R 1 、R 2 and R 3 , it is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). As R 4 and R 5 , it 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 further preferably 3. In addition, when R 4 and R 5 are bonded to form a ring structure together with a nitrogen atom, it is preferably a 4- to 8-membered ring. It should be noted that the alkoxy group also includes a cycloalkoxy group (such as cyclohexyloxy) and an aryloxy group (such as phenoxy and benzyloxy).

[0101] As specific examples of the above modifier, 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. can be mentioned. They can be used alone or in combination of two or more.

[0102] In addition, as the modified BR, modified BR obtained by modifying with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidyl bisphenol A; polyepoxides such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxidized liquid polybutadiene; tertiary amines containing epoxy groups such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl o-toluidine, tetraglycidyl meta-xylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bis(aminomethyl)cyclohexane; acyl chlorides containing amino groups such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamoyl chloride, and N,N-diethylcarbamoyl chloride; silane compounds containing epoxy groups such as 1,3-bis-(glycidoxypropyl)-tetramethyldisiloxane and (3-glycidoxypropyl)-pentamethyldisiloxane; sulfur ether group-containing silane compounds such as (trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide; N-substituted aziridine compounds such as aziridine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, and N,N-bis(trimethylsilyl)aminoethyltriethoxysilane;(Thio)benzophenone compounds having an amino group and / or a substituted amino group, such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-tert-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group, such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone; N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; and N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tri-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylvinylurea, 1,3-divinylvinylurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-acetone, 1,7-bis(methylethylamino)-4-heptanone, etc. It should be noted that the modification by the above compounds (modifiers) can be carried out by known methods. It should be noted that these modified BRs can be used alone or in combination of two or more.

[0103] As the BR, products of, for example, Ube Industries, Ltd., ENEOS Materials Co., Ltd., Asahi Kasei Corporation, Nippon Zeon Co., Ltd., etc. can be used.

[0104] The content of BR in 100 parts by mass of the rubber component is preferably 25 parts by mass or more, more preferably 30 parts by mass or more. On the other hand, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less.

[0105] (④) Other rubber components

[0106] In the rubber composition, as other rubber components, rubber (polymers) such as nitrile rubber (NBR) that are commonly used in the manufacture of tires can be included as needed.

[0107] It should be noted that the raw materials (monomers) of the above synthetic rubbers such as SBR and BR can be derived from underground resources such as petroleum and natural gas, or can be recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0108] As the monomers obtained by recycling (recycled monomers), there is no particular limitation, and examples include recycled isoprene, recycled butadiene, recycled aromatic vinyl monomers, etc. As the above butadiene, 1,2-butadiene and 1,3-butadiene can be cited. As the above aromatic vinyl monomer, there is no particular limitation, and styrene etc. can be cited. Among them, recycled isoprene (recycled isoprene), butadiene (recycled butadiene) and / or recycled styrene (recycled styrene) are preferably used as raw materials.

[0109] As the manufacturing method of the recycled monomer, there is no particular limitation, and examples include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. In addition, as the manufacturing method of the recycled naphtha, there is no particular limitation, and for example, rubber products such as tires can be decomposed under high temperature and high pressure, or can be decomposed by microwaves, or can be extracted after mechanical pulverization.

[0110] In addition, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR can be derived from biomass. In this specification, biomass refers to substances from natural resources such as plants. As biomass, there is no particular limitation, and examples include agricultural, forestry, and fishery products, sugars, woods, plant residues after obtaining useful components, plant-derived ethanol, biomass naphtha, etc.

[0111] As the monomers from biomass (biomass monomers), there is no particular limitation, and examples include butadiene from biomass, aromatic vinyl monomers from biomass, etc. As the above butadiene, 1,2-butadiene and 1,3-butadiene can be cited. As the above aromatic vinyl monomer, there is no particular limitation, and styrene etc. can be cited. In addition, the manufacturing method of the biomass monomer is not particularly limited, and examples include methods based on biological and / or chemical and / or physical conversion of animals and plants. As biological conversion, fermentation using microorganisms is representative, and as chemical and physical conversion, conversion using catalysts, conversion using high heat, conversion using high pressure, conversion using electromagnetic waves, conversion using critical liquids, and combinations thereof can be cited.

[0112] As a polymer synthesized from biomass monomer components (biomass polymer), there is no particular limitation, and examples include polybutadiene rubber synthesized from butadiene derived from biomass, aromatic vinyl monomer / butadiene copolymers synthesized from butadiene derived from biomass and / or aromatic vinyl monomers derived from biomass, and the like. As the above-mentioned aromatic vinyl monomer / butadiene copolymer, for example, styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass can be mentioned.

[0113] Whether the raw material of the polymer is derived from biomass can be judged by pMC (percent Modern Carbon) measured according to ASTM D 6866-10.

[0114] pMC refers to the 14 ratio of the C concentration of the sample to the 14 C concentration of the modern standard reference, and it is a value used as an index to represent the biomass ratio of a compound. The meaning of this value is as described below.

[0115] In 1 mole (6.02×10 23 ), there are about one trillionth of ordinary carbon atoms, that is, about 6.02×10 11 14 C. 14 C is called a radioactive isotope, and its half-life is 5730 years and it decreases regularly. It takes 226,000 years for all of them to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken in and immobilized by plants and the like, it is considered that in fossil fuels such as coal, oil, and natural gas that have passed more than 226,000 years, all of the 14 C elements contained in these substances at the beginning of immobilization have decayed. Therefore, in the present of the 21st century, fossil fuels such as coal, oil, and natural gas do not contain 14 C elements at all. Therefore, chemical substances produced from these fossil fuels also do not contain 14 C elements at all.

[0116] On the other hand, cosmic rays undergo nuclear reactions in the atmosphere and continuously generate 14 C, which is in balance with the decrease caused by radioactive decay. In the atmospheric environment of the earth, 14 the amount of C is a certain amount. Therefore, in the current environment, the 14 C concentration of substances derived from biomass resources in the material cycle is about 1×10 -12 mol% relative to the overall C atoms as described above. Therefore, by using the difference between these values, the biomass ratio in a certain compound can be calculated.

[0117] This​14 C is usually measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, 13 the concentration of 13 C / 12 C), 14 the concentration of 14 C / 12 C) is measured. In the measurement, the 14 C concentration in the cyclic carbon in nature in 1950 is used as 14 the reference for the 14 C concentration, that is, the modern standard reference. As a specific reference material, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) is used. The specific radioactivity of carbon in this oxalic acid (the radioactivity intensity of 13 C per 1 g of carbon) is separated into each carbon isotope, corrected to a certain value for 14 C, and decay correction is performed from 1950 AD to the measurement date. The obtained value is used as the value of the standard

[0118] C concentration (100%). The ratio of this value to the value of the actually measured sample becomes the pMC value.

[0118] Therefore, if rubber is made from a substance that is 100% derived from biomass, although there are regional differences, etc., it generally does not reach 100 under normal conditions at present, so it shows a value of about 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring the 14 C concentration, it shows a value of about 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% as mentioned above.

[0119] In summary, from the aspect of environmental protection (sustainability), it is suitable to use rubber and other materials with a high pMC value, that is, rubber and other materials with a high biomass ratio (sustainable materials), in the rubber composition.

[0120] (b) Compounding materials other than rubber components

[0121] (①) Filler

[0122] The rubber composition preferably contains silica or carbon black as a reinforcing agent, but other fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, vulcanized rubber particles (rubber powder), etc. can also be contained as needed. It should be noted that when using silica, it is preferably used in combination with a silane coupling agent.

[0123] As the compounding amount of the filler, relative to 100 parts by mass of the rubber component, it is preferably at least more than 75 parts by mass of silica, and the total compounding amount with other fillers is preferably 80 parts by mass or more, more preferably 90 parts by mass or more relative to 100 parts by mass of the rubber component. On the other hand, from the aspect of dispersibility in the rubber composition, it is preferably 150 parts by mass or less, more preferably 100 parts by mass or less.

[0124] (i) Silica

[0125] As described above, silica has OH groups on its surface and can capture ozone, so the ozone resistance is improved and the durability of the tire can be enhanced. Also, by containing a large amount of more than 75 parts by mass, hydrogen bonds are generated between the silica surfaces and interact with the rubber component as well. Therefore, during driving, forces can be easily generated and transmitted inside the rubber, and the forces generated during turning can be easily transmitted, ensuring excellent handling stability.

[0126] From the aspect of obtaining good durability performance, the BET specific surface area of silica is preferably more than 100 m 2 / g, more preferably more than 130 m 2 / g. On the other hand, it is preferably less than 250 m 2 / g, more preferably less than 200 m 2 / g. It should be noted that the above BET specific surface area is the N2SA value measured by the BET method in accordance with ASTM D3037-93.

[0127] As silica, there is no particular limitation, and silica commonly used in the tire industry such as silica prepared by the dry method (anhydrous silica) and silica prepared by the wet method (hydrous silica) can be used. As commercially available products, products of Evonik Industries, Rhodia, Tosoh Silica Corporation, Solvay Japan Co., Ltd., Tokuyama Corporation, etc. can be used.

[0128] As the raw material of silica, there is no particular limitation. For example, it can be a raw material from mineral sources such as quartz, or a raw material from biological sources such as rice husks (for example, silica using biomass materials such as rice husks as raw materials), and recycled silica from products containing silica can also be used. Among them, due to the large number of silanol groups, hydrous silica prepared by the wet method is preferred. These silicas can be used alone or in combination of two or more.

[0129] Silica (biomass silica) made from biomass materials can be obtained, for example, as follows: Silicate is extracted from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and the precipitate of silica produced by reacting with sulfuric acid is filtered, washed with water, dried, and pulverized using this silicate in the same manner as existing wet silica, whereby it can be obtained.

[0130] Silica recycled from products containing silica (recycled silica) can use, for example, silica recovered from products containing silica such as semiconductor and other electronic components, tires, desiccants, and filter materials such as diatomaceous earth. In addition, as the recovery method, there is no particular limitation, and thermal decomposition, decomposition using electromagnetic waves, etc. can be cited. Among them, silica recycled from semiconductor and other electronic components or tires is preferred.

[0131] If silica crystallizes, it is insoluble in water and the silicic acid as its component cannot be utilized. By controlling the combustion temperature and combustion time, crystallization of silica in rice husk ash can be suppressed (refer to Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, p. 216-222, etc.).

[0132] Amorphous silica extracted from rice husks can use commercially available amorphous silica such as that from Wilmar Corporation.

[0133] It should be noted that these silicas can be used alone or in combination of two or more. It should be noted that from the aspect of environmental protection, it is suitable to use sustainable silicas such as biomass silica obtained using biomass as a raw material and recycled silica obtained from the recycling of used products or waste materials.

[0134] As described above, the content of silica relative to 100 parts by mass of the rubber component is preferably more than 75 parts by mass relative to 100 parts by mass of the rubber component, more preferably 80 parts by mass or more, and still more preferably 90 parts by mass or more. As the upper limit, for example, it is preferably 150 parts by mass or less, and more preferably 100 parts by mass or less.

[0135] (ii) Silane coupling agent

[0136] When using silica, in order to improve the dispersibility of silica and achieve improvements in mechanical properties, moldability, etc. through reaction with silica, it is preferable to use a silane coupling agent in combination.

[0137] As the silane coupling agent, there is no particular limitation, 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, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide and other sulfur-containing compounds, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, NXT, NXT-Z manufactured by Momentive and other mercapto compounds, vinyltriethoxysilane, vinyltrimethoxysilane and other vinyl compounds, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane and other amino compounds, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and other glycidoxy compounds, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane and other nitro compounds, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane and other chlorine compounds. Among them, a silane coupling agent having a thiocarbonyl group such as the above-mentioned NXT is preferred. They can be used alone or in combination of two or more.

[0138] As the silane coupling agent, products of Evonik Industries, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., AZmax Co., Ltd., Toray Dow Corning Co., Ltd. etc. can be used.

[0139] The content of the silane coupling agent is preferably more than 3 parts by mass, more preferably 5 parts by mass or more, and still more preferably 7 parts by mass or more, relative to 100 parts by mass of the silica. As the upper limit, it is preferably less than 15 parts by mass, more preferably 12 parts by mass or less, and still more preferably 9 parts by mass or less.

[0140] (iii) Carbon black

[0141] The carbon black is preferably used for the purpose of improving the crack growth resistance, durability, ultraviolet degradation resistance etc. of the tire.

[0142] From the aspect of the reinforcing property of rubber, the nitrogen adsorption specific surface area (N2SA) of carbon black is, for example, preferably 30 m 2 / g or more, more preferably 50 m 2 / g or more, and still more preferably 60 m 2 / g or more. On the other hand, from the aspect of heat generation property, it is preferably 250 m 2 / g or less, more preferably 150 m 2 / g or less, and still more preferably 120 m 2 / g or less. It should be noted that the nitrogen adsorption specific surface area of carbon black is measured according to ASTM D4820-93.

[0143] From the aspect of the rigidity of rubber, the dibutyl phthalate (DBP) absorption of carbon black is, for example, preferably 50 ml / 100 g or more, more preferably 100 ml / 100 g or more. On the other hand, from the aspect of the followability of rubber deformation, it is preferably 250 ml / 100 g or less, more preferably 150 ml / 100 g or less. It should be noted that the DBP absorption of carbon black is measured according to ASTM D2414-93.

[0144] There is no particular limitation on the carbon black, and examples thereof include furnace black such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF (Furnace carbonblack); acetylene black (Acetylene carbon black); thermal carbon black such as FT and MT (Thermal carbonblack); channel black such as EPC, MPC, and CC (Channelcarbon black), etc. In addition, as part numbers, examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. They can be used alone or in combination of two or more.

[0145] In addition to mineral oil, the raw material of carbon black can also be biomass materials such as lignin and vegetable oil, or recycled materials such as pyrolysis oil obtained by pyrolyzing rubber products such as waste tires. From the aspect of environmental protection, it is suitable to use sustainable carbon blacks such as biomass carbon black made from biomass materials and recycled carbon black made from recycled materials such as used products or waste materials.

[0146] In addition, the carbon black can be manufactured by combustion such as the furnace method, by hydrothermal carbonization (HTC), or by thermal decomposition of methane based on the thermal carbon black method, etc.

[0147] As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, LION Corporation, Nippon Steel Carbon Co., Ltd., Columbian Carbon Company, etc. can be used. They can be used alone or in combination of two or more.

[0148] The content of carbon black relative to 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more. As the upper limit, for example, it is preferably 25 parts by mass or less, more preferably 20 parts by mass or less.

[0149] (iv) Other fillers

[0150] In addition to the above carbon black and silica, the rubber composition may further contain fillers such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, magnesium sulfate, etc. which are commonly used in the tire industry. Their content is, for example, more than 0.1 part by mass and less than 150 parts by mass relative to 100 parts by mass of the rubber component.

[0151] (②) Softener (plasticizer) component

[0152] In the rubber composition, from the aspect of imparting plasticity to the rubber component during mixing and properly dispersing the powder materials, it is preferably to use a softener (plasticizer) component as needed. It should be noted that the softener component here is a concept including both softeners that are liquid at 25°C and softeners that are solid at 25°C.

[0153] Examples of softeners can include resin components, oils, liquid polymers, ester plasticizers, etc. These softeners can be derived from mineral resources such as petroleum or natural gas, or from biomass, or from naphtha recycled from rubber products or non-rubber products. In addition, low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components can also be used as softeners, among which softeners derived from biomass or recycled ones are preferably used as sustainable softeners.

[0154] It should be noted that these softeners can be used alone or in combination of two or more. As the content of the softener component relative to 100 parts by mass of the rubber component, it is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 25 parts by mass or more. As the upper limit, for example, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and further preferably 30 parts by mass or less. It should be noted that the content of the softener component also includes the amount of oil contained in rubber (oil-extended rubber), etc.

[0155] (i) Oil

[0156] As the oil, for example, mineral oil, vegetable oil, animal oil, etc. can be cited. In addition, from the aspect of life cycle assessment, oil refined from waste oil used in a rubber mixer or an engine, or waste cooking oil used in a cooking shop can also be used.

[0157] (i-1) Mineral oil

[0158] In this specification, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. As mineral oil, paraffinic oil (mineral oil), naphthenic oil, aromatic oil, etc. can be cited.

[0159] As specific mineral oil, for example, MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), etc. can be cited.

[0160] In addition, for environmental countermeasures, oil with a low content of polycyclic aromatic compound (PCA) can also be used. As the above-mentioned low-PCA-content oil, MES, TDAE, heavy naphthenic oil, etc. can be cited.

[0161] As commercially available mineral oil, for example, paraffinic, aromatic, naphthenic, etc. oils can be cited, and products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, OLISOY, H&R, Toyokuni Oil Co., Ltd., Showa Shell Sekiyu KK, Fuji Kogyo Co., Ltd., etc. can be used. They can be used alone or in combination of two or more.

[0162] (i-2) Vegetable oil

[0163] As vegetable oil, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, fragrant oil, castor oil, tung oil, pine oil, pine tar, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc. can be cited.

[0164] In addition, as vegetable oils, refined oils (such as salad oil) obtained by refining the above-mentioned various oils, transesterified oils after transesterification, solidified oils after hydrogenation, thermally polymerized oils after thermal polymerization, oxidation-polymerized oils after oxidation, waste cooking oils recovered after being used as cooking oils, etc. may also be mentioned. It should be noted that vegetable oils can be liquid or solid at normal temperature (25°C). They can be used alone or in combination of two or more.

[0165] As vegetable oils, acylglycerols are preferably included, and triacylglycerols are more preferably included. It should be noted that acylglycerols refer to compounds in which the hydroxyl groups of glycerol form ester bonds with fatty acids. As acylglycerols, there is no particular limitation, and they can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. In addition, acylglycerols can be monomers, dimers, or polymers of trimers or more. It should be noted that acylglycerols of dimers or more can be obtained by thermal polymerization, oxidation polymerization, etc. In addition, acylglycerols can be liquid or solid at normal temperature (25°C).

[0166] As a method for confirming whether an acylglycerol is contained in a rubber composition, there is no particular limitation, and it can be confirmed by 1 1H-NMR measurement. For example, a rubber composition mixed with triacylglycerol is immersed in deuterated chloroform at normal temperature (25°C) for 24 hours. After removing the rubber composition, 1H-NMR is measured at room temperature. 1 When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm are observed. It is speculated that these signals are signals from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. Therefore, it can be confirmed that acylglycerols are contained. It should be noted that the term "around" here refers to a range of ±0.10 ppm.

[0167] It should be noted that as fatty acids, there is no particular limitation, and they can be unsaturated fatty acids or saturated fatty acids. As unsaturated fatty acids, monovalent unsaturated fatty acids such as oleic acid, and polyvalent unsaturated fatty acids such as linoleic acid and linolenic acid can be mentioned. In addition, as saturated fatty acids, butyric acid, lauric acid, etc. can be mentioned.

[0168] Among them, as the above-mentioned fatty acids, fatty acids with fewer double bonds, that is, saturated fatty acids or monovalent unsaturated fatty acids, are preferably included, and oleic acid is preferred. As vegetable oils containing such fatty acids, for example, vegetable oils containing saturated fatty acids or monovalent unsaturated fatty acids can be used, or vegetable oils modified by transesterification or the like can be used. In addition, in order to produce vegetable oils containing such fatty acids, plants can also be improved by variety improvement, genetic recombination, genome editing, etc.

[0169] As the vegetable oil, commercially available vegetable oils such as those produced by Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, OLISOY, H&R, Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., and Nisshin Oillio Group, Ltd. can be used.

[0170] (ii) Liquid rubber

[0171] Liquid rubber refers to a polymer that is in a liquid state at normal temperature (25 °C) and is a rubber component that can be extracted from vulcanized tires by acetone extraction. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and their hydrides.

[0172] Farnesene-based polymers refer to polymers obtained by polymerizing farnesene and having a structural unit based on farnesene. Isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene) exist in farnesene.

[0173] The farnesene-based polymer can be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

[0174] Examples of liquid diene-based 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).

[0175] The polystyrene-reduced weight-average molecular weight (Mw) of the liquid diene-based polymer measured by gel permeation chromatography (GPC) is, for example, more than 1.0×10 3 and less than 2.0×10 5 . Here, the Mw of the liquid diene-based polymer is a polystyrene-reduced value measured by gel permeation chromatography (GPC).

[0176] As the liquid rubber, products of, for example, KURARAY Co., Ltd. and Cray Valley can be used.

[0177] (iii) Resin component

[0178] It is preferable to contain a resin component in the tread rubber composition. By containing a resin component in the rubber composition, the ground contact property with the road surface is improved by the adhesiveness of the resin component, and thus it is considered that the rolling resistance at the start can be further reduced.

[0179] The resin component also functions as an adhesion - imparting component and can be solid or liquid at room temperature. As specific resin components, for example, rosin - based resins, styrene - based resins, benzofuran - based resins, terpene - based resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc. are preferred, and two or more of them can be used in combination. It should be noted that these resin components can also be provided with modified groups capable of reacting with silica, etc. as required. And, as the content relative to 100 parts by mass of the rubber component, it is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 50 parts by mass or more.

[0180] Rosin - based resins are resins mainly composed of rosin acid obtained by processing pine resin. This rosin - based resin (rosin type) can be classified according to whether it is modified or not, and can be classified into unmodified rosin (unmodified rosin), rosin modifiers (rosin derivatives). As unmodified rosin, tall oil rosin (also known as tall oil pitch), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins can be cited. Rosin modifiers are modifiers of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid - modified rosins, unsaturated carboxylic acid - modified rosin esters, amide compounds of rosin, amine salts of rosin, etc.

[0181] Styrene - based resins are polymers using styrene - based monomers as constituent monomers, and examples include polymers obtained by polymerizing styrene - based monomers as the main component (50% by mass or more). Specifically, in addition to homopolymers obtained by homopolymerizing each styrene - based monomer (styrene, o - methylstyrene, m - methylstyrene, p - methylstyrene, α - methylstyrene, p - methoxystyrene, p - tert - butylstyrene, p - phenylstyrene, o - chlorostyrene, m - chlorostyrene, p - chlorostyrene, etc.) and copolymers obtained by copolymerizing two or more styrene - based monomers, copolymers of styrene - based monomers and other monomers capable of copolymerizing with them can also be cited.

[0182] As the above - mentioned other monomers, examples include acrylonitrile - based monomers such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene, butadiene, and isoprene, olefins such as 1 - butene and 1 - pentene; α,β - unsaturated carboxylic acids or their acid anhydrides such as maleic anhydride; etc.

[0183] Among benzofuran - based resins, benzofuran - indene resins are preferred. Benzofuran - indene resins are resins containing benzofuran and indene as monomer components constituting the resin skeleton (main chain). As monomer components contained in the skeleton in addition to benzofuran and indene, styrene, α - methylstyrene, methyl indene, vinyltoluene, etc. can be cited.

[0184] 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 refers to the amount of potassium hydroxide required to neutralize acetic acid bonded to the hydroxyl group when 1 g of the resin is acetylated, expressed in milligrams, and is a value measured by potentiometric titration (JIS K 0070: 1992).

[0185] The softening point of the coumarone indene resin is, for example, higher than 30° C. and lower than 160° C. The softening point is a softening point specified in JIS K 6220-1:2001 and measured using a ring and ball softening point measuring apparatus, and is a temperature at which a ball falls.

[0186] 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 composed of (C5H8) n The hydrocarbons and their oxygenated derivatives are classified as monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 ) and the like as a basic skeleton, for example, 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, γ-terpineol, etc. can be mentioned.

[0187] As polyterpenes, in addition to terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc. which are made from the above-mentioned terpene compounds as raw materials, hydrogenated terpene resins obtained by hydrogenating the terpene resins can also be cited. As terpene phenols, resins copolymerized from the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating the resins can be cited. Specifically, resins formed by condensing the above-mentioned terpene compounds, phenolic compounds and formaldehyde can be cited. It should be noted that as phenolic compounds, for example, phenol, bisphenol A, cresol, xylenol, etc. can be cited. As aromatic modified terpene resins, resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating the resins can be cited. It should be noted that as aromatic compounds, as long as they are compounds having an aromatic ring, there is no particular limitation, and for example, phenolic compounds such as phenol, alkylphenol, alkoxyphenol, phenol containing an unsaturated hydrocarbon group, etc.; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, naphthol containing an unsaturated hydrocarbon group, etc.; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, styrene containing an unsaturated hydrocarbon group, etc.; benzofuran, indene, etc. can be cited.

[0188] "C5 resin" refers to a resin obtained by polymerizing C5 fractions. As C5 fractions, for example, petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, isoprene, etc. can be cited. As C5 petroleum resins, dicyclopentadiene resin (DCPD resin) is preferably used.

[0189] "C9 resin" refers to a resin obtained by polymerizing C9 fractions, or a resin obtained by hydrogenating or modifying them. As C9 fractions, for example, petroleum fractions corresponding to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, methylindene, etc. can be cited. As a specific example, for example, benzofuran indene resin, benzofuran resin, indene resin and aromatic vinyl resin are preferably used. As aromatic vinyl resins, due to reasons such as economy, easy processing, and excellent heat generation properties, α-methylstyrene (AMS resin) or a homopolymer of styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred. As aromatic vinyl resins, for example, aromatic vinyl resins commercially available from KRATON Corporation, Eastman Chemical Company, etc. can be used.

[0190] "C5C9 resin" refers to a resin obtained by copolymerizing the above-mentioned C5 fractions and the above-mentioned C9 fractions, or a resin obtained by hydrogenating or modifying them. As C5 fractions and C9 fractions, the above-mentioned petroleum fractions can be cited. As C5C9 resins, for example, resins commercially available from Tosoh Corporation, LUHUA Company, etc. can be used.

[0191] The acrylic resin is not particularly limited, and for example, a solvent-free acrylic resin can be used.

[0192] Solvent-free acrylic resins include (meth) acrylic resins (polymers) synthesized by a high temperature continuous polymerization method (high temperature continuous bulk polymerization method) (methods described in U.S. Patent No. 4,414,370, Japanese Patent Publication No. 59-6207, Japanese Patent Publication No. 5-58005, Japanese Patent Publication No. 1-313522, U.S. Patent No. 5,010,166, East Asia Synthesis Research Annual Report TREND 2000 No. 3, p. 42-45, etc.) without using a polymerization initiator, a chain transfer agent, an organic solvent, etc. as secondary raw materials as much as possible. It should be noted that in the present invention, (meth) acrylic acid refers to methacrylic acid and acrylic acid.

[0193] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, arylalkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0194] As monomer components constituting the acrylic resin, aromatic vinyl monomers 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.

[0195] The acrylic resin may be a resin composed only of a (meth)acrylic acid component or a resin containing components other than the (meth)acrylic acid component as constituent elements. In addition, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0196] As the resin component, for example, products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, KRATON, Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0197] (③) Wax

[0198] The rubber composition may contain wax. The content of the wax 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, relative to 100 parts by mass of the rubber component.

[0199] As the wax, there is no particular limitation, and any wax commonly used in the tire industry can be suitably used. For example, mineral waxes, waxes of plant origin, etc. can be cited. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Waxes of plant origin refer to waxes derived from natural resources such as plants. Among them, mineral waxes are preferred.

[0200] As waxes of plant origin, for example, rice bran wax, carnauba wax, candelilla wax, etc. can be cited. As mineral waxes, for example, paraffin wax, microcrystalline wax, their selected special waxes, etc. can be cited, and paraffin wax is preferred. It should be noted that in the present invention, the wax does not include stearic acid.

[0201] It should be noted that as the wax, for example, waxes commercially available from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Corporation, etc. can be used. These waxes can be used alone or in combination of two or more.

[0202] (④)Antioxidant

[0203] 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 relative to 100 parts by mass of the rubber component.

[0204] There is no particular limitation on the antioxidant, and examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine-based antioxidants such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-dimethylxyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bisphenol-based, triphenol-based, polyphenol-based antioxidants such as tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, etc. Among them, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. They can be used alone or in combination of two or more.

[0205] As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Corporation, etc. can be used.

[0206] (⑤) Processing aids

[0207] The rubber composition may contain processing aids. Examples of the processing aids include metal salts (compounds in which the hydrogen atoms of an acid are replaced by metal ions), fatty acid amides, amide esters, fatty acid esters, etc. They may be used alone or in combination of two or more. Among them, metal salts and fatty acid amides are preferred, and metal salts are more preferred.

[0208] Examples of the metal used in the metal salt include alkali metals such as potassium and sodium, alkaline earth metals such as calcium and barium, etc. In addition, magnesium, zinc, nickel, molybdenum, etc. may also be used. Among them, alkali metals are preferred.

[0209] Examples of the acid used in the metal salt include fatty acids such as lauric acid, myristic acid, and palmitic acid. In addition, boric acid, carbonic acid, hydrochloric acid, nitric acid, sulfuric acid, etc. may also be used.

[0210] As commercially available products of the processing aids, products of Kishida Chemical Co., Ltd., Kenzo Pharmaceutical Co., Ltd., Struktol Company, Performance Additives Company, etc. can be used.

[0211] The content of the processing aids is preferably 1 part by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of the rubber component. As the upper limit, for example, it is preferably 6 parts by mass or less, more preferably 4 parts by mass or less.

[0212] (⑥) Lubricant (stearic acid)

[0213] The rubber composition may contain a lubricant. As the lubricant, a lubricant based on fatty acid derivatives such as stearic acid is preferably used. As the stearic acid, conventionally known stearic acid can be used. Specifically, products of Nippon Oil Corporation, NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Corporation, Chiba Fatty Acids Co., Ltd., etc. can be used. In addition, Struktol WB16 manufactured by Struktol Company can also be used.

[0214] The content of stearic acid is preferably more than 0.5 part by mass and less than 10.0 parts by mass relative to 100 parts by mass of the rubber component.

[0215] (⑦) Zinc oxide

[0216] 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 with respect to 100 parts by mass of the rubber component. As the zinc oxide, publicly known zinc oxides can be used, and products of, for example, Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., HAKUSUI TECH Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd. etc. can be used.

[0217] (⑧) Crosslinking agent and vulcanization accelerator

[0218] 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 with respect to 100 parts by mass of the rubber component. It should be noted that the content of sulfur is the pure sulfur component, and in the case of using insoluble sulfur, it is the content after removing the oil component.

[0219] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc. which are commonly used in the rubber industry. They can be used alone or in combination of two or more.

[0220] It should be noted that as sulfur, products of, for example, Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Co., Ltd., Nippon Kankyo Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd. etc. can be used.

[0221] Crosslinking agents other than sulfur can also be used. Specifically, for example, TACKROLV200 manufactured by Taoka Chemical Industry Co., Ltd., DURALINK HTS (1,6 - hexamethylene - disodium dithiocarbamate dihydrate) manufactured by Flexis Co., Ltd., KA9188 (1,6 - bis(N,N’ - dibenzylthiocarbamoyl disulfide): hybrid crosslinking agent) manufactured by LANXESS Co., Ltd. etc., sulfur - containing vulcanizing agents, organic peroxides such as dicumyl peroxide etc. can be used.

[0222] Furthermore, the rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, more than 0.3 parts by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0223] As vulcanization accelerators, there can be mentioned thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, bis(2-benzothiazolyl) disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, etc.; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), tetra(2-ethylhexyl)thiuram disulfide (TOT-N), etc.; sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolesulfenamide, N-tert-butyl-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N,N'-diisopropyl-2-benzothiazolesulfenamide, etc.; guanidine-based vulcanization accelerators such as diphenylguanidine, di-o-tolylguanidine, o-tolylbiguanide, etc. They can be used alone or in combination of two or more.

[0224] (⑨) Others

[0225] In the rubber composition, in addition to the above components, additives commonly used in the tire industry, such as organic fillers such as cellulose fibers, organic peroxides, etc., can also be compounded as needed. The content of these additives is, for example, more than 0.1 part by mass and less than 50 parts by mass relative to 100 parts by mass of the rubber component.

[0226] It should be noted that in the present invention, various materials containing carbon atoms in the above-mentioned materials (such as rubber, oil, resin, vulcanization accelerator, anti-aging agent, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining the composition of the present invention from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process for synthesizing methane via carbon dioxide can be converted.

[0227] (2) Preparation of rubber composition

[0228] The rubber composition can be prepared by a general method, for example, a manufacturing method including a basic kneading process of kneading rubber components and fillers such as silica, and a refining kneading process of kneading the kneaded product obtained in the above basic kneading process and a crosslinking agent.

[0229] Kneading can be carried out using a known (closed type) kneader such as a Banbury mixer, a kneader, an open mill, etc.

[0230] The kneading temperature in the basic kneading process is, for example, more than 50°C and less than 200°C, and the kneading time is, for example, more than 30 seconds and less than 30 minutes. In the basic kneading process, in addition to the above components, compounding agents commonly used in the existing rubber industry, such as softening agents such as oil, stearic acid, zinc oxide, anti-aging agents, wax, vulcanization accelerators, etc., can also be appropriately added as needed and kneaded.

[0231] In the refining and kneading process, the kneaded product obtained in the above-mentioned basic kneading process and a crosslinking agent are kneaded. The kneading temperature in the refining and kneading process 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 refining and kneading process, in addition to the above components, vulcanization accelerators, zinc oxide, etc. can also be appropriately added as needed and kneaded.

[0232] After that, the rubber composition obtained above is extruded and processed into a specified shape, whereby it can be formed into a tread.

[0233] 3. Manufacture of tires

[0234] The tire of the present embodiment can be manufactured by a conventional method. First, using the rubber composition obtained above, it is formed into a specified shape to manufacture a tread. Next, it is combined with other rubber components on a tire molding machine to produce an unvulcanized tire.

[0235] Specifically, on a molding drum, an inner liner layer as a component for ensuring the airtightness of the tire, a carcass as a component for bearing the load, impact, and inflation pressure of the tire, a belt layer component as a component for strongly clamping the carcass and improving the tread rigidity, a chafer, etc. are wound. While fixing both ends of the carcass at both side edges, a bead portion as a component for fixing the tire to a rim is arranged. After forming into a ring shape, by attaching the tread to the central portion of the outer periphery and attaching the sidewall to the radially outer side to form a sidewall portion, an unvulcanized tire is produced.

[0236] Then, the unvulcanized tire produced above is heated and pressurized in a vulcanizer to obtain a tire. The vulcanization process can be carried out by applying known vulcanization means. As the vulcanization temperature, for example, it is 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.

[0237] In the tire obtained above, as described above, by appropriately controlling the product of the tire weight (kg) and the diameter (mm) of the chafer cord, the effects brought by using a PET chafer belt and the effects brought by an appropriately formed tire weight (the ratio of the tire weight to the maximum load-carrying capacity) act synergistically, and it is possible to improve the comprehensive performance of low fuel consumption and high-speed durability.

[0238] Moreover, the tire of the present invention can be suitably used as a passenger car tire, a large passenger car tire, a large SUV tire, a truck-bus tire, a two-wheeler tire, a racing tire, a studless winter tire, an all-season tire, a run-flat tire, etc., and is particularly preferably used as a passenger car tire.

[0239] Examples

[0240] Examples (embodiments) considered preferable in implementation are shown below, but the scope of the present invention is not limited to these embodiments.

[0241] Research was conducted on tires (tire size: 195 / 65R15) composed of treads and tire components such as crown ply and belt ply formed from various compounding materials shown below, and the results calculated based on the evaluation methods described later regarding low fuel consumption and high-speed durability are shown together in the lower parts of Tables 2 and 3.

[0242] 1. Preparation of rubber composition

[0243] Using the various compounding materials shown below, a rubber composition for tread was prepared.

[0244] (1) Compounding materials

[0245] (a) Rubber components

[0246] (①) NR: TSR20

[0247] (②) SBR-1: Modified S-SBR (styrene content: 25% by mass, vinyl content: 63 mol%, Tg: -20°C, non-extended oil) manufactured based on Production Example 1 described later

[0248] (③) SBR-2: Modified S-SBR (styrene content: 24% by mass, vinyl content: 59 mol%, Tg: -25°C, non-extended oil) manufactured based on Production Example 2 described later

[0249] (④) SBR-3: HPR840 (modified S-SBR, styrene content: 10% by mass, vinyl content: 42 mol%, Tg: -60°C, non-extended oil) manufactured by ENEOS Materials Co., Ltd.

[0250] (⑤) BR-1: BR730 (cis content: 96% by mass, trans content: 3% by mass, vinyl content: 1% by mass) manufactured by ENEOS Materials Co., Ltd.

[0251] (⑥) BR-2: ASAPREN N103 (cis content: 38% by mass, Tg: -90°C) manufactured by Asahi Kasei Corporation

[0252] (⑦) BR-3: BR360B (cis content: 97% by mass, trans content: 1% by mass, vinyl content: 2% by mass) manufactured by Ube Industries, Ltd.

[0253] (Production Example 1)

[0254] The above SBR-1 was produced according to the following steps. First, cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene were charged into a high-pressure autoclave reactor purged with nitrogen. After adjusting the temperature of the reactor contents, n-butyllithium was added to initiate polymerization. Thereafter, polymerization was carried out under adiabatic conditions. At the moment when the polymerization conversion reached 99%, 1,3-butadiene was added, and polymerization was further carried out for 5 minutes. Then, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane was added as a modifier for reaction. After the polymerization reaction ended, 2,6-di-tert-butyl-p-cresol was added, the solvent was removed by stripping, and drying was carried out using a hot roll to obtain SBR-1.

[0255] (Production Example 2)

[0256] The above SBR-2 was obtained in the same manner as in Production Example 1, except that the target styrene content, vinyl content, Tg were changed and the modifier was 3-dimethylaminopropyltriethoxysilane.

[0257] (b) Compounding materials other than the rubber component

[0258] (①) Carbon black: DIABLACK N220 manufactured by Mitsubishi Chemical Corporation

[0259] (N2SA: 115m 2 / g)

[0260] (②) Silica: ULTRASIL VN3 manufactured by Evonik Industries AG

[0261] (N2SA: 175m 2 / g, average primary particle size: 17 nm)

[0262] (③) Silane coupling agent: NXT manufactured by Momentive Performance Materials Inc.

[0263] (3-octanoylthiopropyltriethoxysilane)

[0264] (④) Oil: Processing oil A / OMIX manufactured by Sankyo Yuka Kogyo Co., Ltd.

[0265] (⑤) Resin: YS resin PX850 manufactured by Yasuhara Chemical Co., Ltd.

[0266] (Softening point 85°C, β-pinene resin (terpene resin))

[0267] (⑥) Wax: OZOACE 0355 manufactured by Nippon Seiro Co., Ltd.

[0268] (⑦) Anti-aging agent-1: NOCRAC 6C manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

[0269] (N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine)

[0270] (⑧)Antioxidant - 2: ANTAGE RD manufactured by Kawaguchi Chemical Industry Co., Ltd.

[0271] (Poly(2,2,4-trimethyl-1,2-dihydroquinoline)

[0272] (⑨)Antioxidant - 3: Sirantech S-TMQ manufactured by Sennics Co., Ltd.

[0273] (Poly(2,2,4-trimethyl-1,2-dihydroquinoline)

[0274] (⑩)Processing Aid - 1: NOCCELERCZ manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

[0275] (N-Cyclohexylbenzothiazole-2-sulfenamide)

[0276] Processing Aid - 2: NOCCELER D manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

[0277] (1,3-Diphenylguanidine (DPG))

[0278] Processing Aid - 3: NOCCELER M-P manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

[0279] (2-Mercaptobenzothiazole)

[0280] Stearic acid: Bead stearic acid "Tsubaki" manufactured by NOF Corporation

[0281] Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

[0282] Sulfur: Powder sulfur manufactured by Karuizawa Sulfur Co., Ltd.

[0283] Accelerator - 1: Sanceler CM-G manufactured by Sanshin Chemical Industry Co., Ltd.

[0284] (N-Cyclohexyl-2-benzothiazolylsulfenamide (CBS)

[0285] Accelerator - 2: SOXINOL DG manufactured by Sumitomo Chemical Co., Ltd.

[0286] (1,3-Diphenylguanidine (DPG)

[0287] Accelerator - 3: SUNSINE MBT manufactured by Shandong Shangshun Chemical Co., Ltd.

[0288] (2 - Mercaptobenzothiazole)

[0289] (2) Preparation of the tread rubber composition

[0290] Based on the respective ratios of A to C shown in Table 1, using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd., materials other than sulfur and vulcanization accelerators were kneaded at 150 °C for 5 minutes to obtain a kneaded product.

[0291] Next, sulfur and vulcanization accelerators were added to the kneaded product, and it was kneaded at 80 °C for 5 minutes using a two - roll mill to obtain the tread rubber compositions of ratios A to C.

[0292] 2. Molding of tire components (tread, chafer ply, belt ply, carcass)

[0293] (1) Molding of the tread

[0294] Next, using the rubber composition obtained above, the tread was molded into a specified shape.

[0295] (2) Molding of the chafer ply

[0296] Meanwhile, the specified chafer - ply rubber composition was applied to each chafer - ply cord shown in Tables 2 and 3 to mold each chafer ply.

[0297] (3) Molding of the belt ply

[0298] Similarly, the specified belt - ply rubber composition was applied to each belt - ply cord shown in Tables 2 and 3 to mold each belt ply.

[0299] (4) Molding of the carcass

[0300] Similarly, the specified carcass - ply rubber composition was applied to each carcass cord shown in Tables 2 and 3 to mold each carcass.

[0301] 3. Manufacture of tires

[0302] Next, the obtained treads, chafer plies, belt plies, and carcasses were joined together with other tire components to form an unvulcanized tire, which was then pressure - vulcanized at 170 °C for 10 minutes to manufacture the test tires of Examples 1 to 9 and Comparative Examples 1 to 3.

[0303] 4. Performance evaluation test

[0304] (1) Evaluation of low fuel consumption

[0305] Using a rolling resistance testing machine, measure the rolling resistance coefficient (RRC: Rolling Resistance Coefficient) of each test tire when it travels on a drum at a speed of 80 km / h under the following conditions.

[0306] Rim used: 15×6J

[0307] Inner pressure: 210 kPa

[0308] Load: 4.35 kN

[0309] Next, set the result of Comparative Example 3 as 100, and perform exponentiation based on the following formula as the low fuel consumption evaluation. The larger the value, the better the low fuel consumption performance.

[0310] Rolling resistance evaluation = [(Result of Comparative Example 3) / (Result of the test tire)] × 100

[0311] (2) High-speed durability evaluation

[0312] Assemble each test tire onto a rim (size = 16×6.0J), fill the tire with air, adjust the inner pressure to 280 kPa, then install it on a drum running testing machine, apply a longitudinal load of 4.22 kN, and gradually increase the speed from 200 km / h in increments of 10 km / h. Measure the time and speed until the tire is damaged. Divide the obtained time by the time taken to increase to the next speed, multiply by 10 km / h, and add the obtained value to the obtained speed to calculate the total value.

[0313] Next, set the result of Comparative Example 3 as 100, and perform exponentiation based on the following formula as the index of high-speed durability for evaluation. The larger the value, the better the high-speed durability.

[0314] High-speed durability evaluation = [(Result of the test tire) / (Result of Comparative Example 3)] × 100

[0315] (3) Comprehensive evaluation

[0316] And sum up the results of (1) and (2) as the comprehensive evaluation.

[0317] [Table 1]

[0318]

[0319] [Table 2]

[0320]

[0321] [Table 3]

[0322]

[0323] As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments. Various modifications can be made to the above-described embodiments within the scope identical to and equivalent to the present invention.

[0324] The present invention (1) relates to a tire, which includes:

[0325] a carcass including carcass cords;

[0326] a belt layer including belt cords and disposed radially outside the carcass of the tire;

[0327] a crown belt layer including crown belt cords and disposed radially outside the belt layer of the tire; and

[0328] a tread disposed radially outside the crown belt layer of the tire,

[0329] wherein the tire is characterized in that

[0330] the above-mentioned crown belt cords include polyethylene terephthalate fibers,

[0331] the ratio of the weight (kg) of the above-mentioned tire to the maximum load-carrying capacity (kg) of the above-mentioned tire (tire weight / maximum load-carrying capacity) is less than 0.014,

[0332] the product of the weight (kg) of the above-mentioned tire and the diameter (mm) of the above-mentioned crown belt cords (tire weight × crown belt cord diameter) is less than 4.3.

[0333] The present invention (2) is the tire according to the present invention (1), characterized in that the above-mentioned ratio (tire weight / maximum load-carrying capacity) is less than 0.013.

[0334] The present invention (3) is the tire according to the present invention (2), characterized in that the above-mentioned ratio (tire weight / maximum load-carrying capacity) is less than 0.012.

[0335] The present invention (4) is the tire according to the present invention (3), characterized in that the above-mentioned ratio (tire weight / maximum load-carrying capacity) is less than 0.011.

[0336] The present invention (5) is the tire according to the present invention (4), characterized in that the above-mentioned ratio (tire weight / maximum load-carrying capacity) is less than 0.010.

[0337] The present invention (6) is the tire according to the present invention (1), characterized in that the number of filaments of the above-mentioned belt cords is 1 or more and 4 or less.

[0338] The tire of the present invention (7), as described in the present invention (1), is characterized in that the structure of the belt cord is any one of 1×1 structure, 1×2 structure, 1×3 structure, 1×4 structure or 2+2 structure.

[0339] The tire of the present invention (8), as described in the present invention (1), is characterized in that when looking at the tire from the radially outer side of the tire, the crossing angle of the belt cord with respect to the equatorial plane of the tire is less than 25 degrees.

[0340] The tire of the present invention (9), as described in the present invention (1), is characterized in that the cap ply cord is formed by twisting one yarn (single twist).

[0341] The tire of the present invention (10), as described in the present invention (1), is characterized in that the total fineness of the carcass cord exceeds 2400 dtex.

[0342] The tire of the present invention (11), as described in the present invention (1), is characterized in that the rubber composition forming the tread is a rubber composition containing more than 75 parts by mass of silica with respect to 100 parts by mass of the rubber component.

[0343] The tire of the present invention (12), as described in the present invention (1), is characterized in that the acetone extract component (AE amount) of the rubber composition forming the tread exceeds 15% by mass.

[0344] The tire of the present invention (13), as described in the present invention (1), is characterized in that the polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber.

[0345] The tire of the present invention (14), as described in the present invention (1), is characterized in that the rubber composition forming the tread contains vegetable oil.

[0346] The tire of the present invention (15), as described in the present invention (1), is characterized in that the rubber composition forming the tread contains sustainable carbon black.

[0347] The tire of the present invention (16), as described in the present invention (1), is characterized in that the rubber composition forming the tread contains sustainable silica.

[0348] Symbol Explanation

[0349] 1 Tire

[0350] 2 Tread

[0351] 3 Sidewall

[0352] 4 Abrasion-resistant part

[0353] 5 Bead

[0354] 6 Inner liner

[0355] 7 Carcass

[0356] 8 Belt

[0357] 9 Filler

[0358] 10 Apex

[0359] Equatorial plane of CL tire

Claims

1. A tire, comprising: A carcass having carcass cords; a belt layer including belt layer cords and arranged on the tire radial direction outer side of the carcass; a cap layer including cap layer cords and disposed on the outer side of the belt layer in the tire radial direction; and A tread, which is arranged on the outer side of the cap layer in the tire radial direction, The tire is characterized by: The cap layer cords include polyethylene terephthalate fibers, The ratio of the tire weight to the maximum load-bearing capacity of the tire, i.e., tire weight / maximum load-bearing capacity, is less than 0.014, wherein: The unit of the tire weight is kg, the unit of the maximum load capacity is kg, The product of the tire weight and the diameter of the cap layer cord, ie, tire weight×the diameter of the cap layer cord, is less than 4.3, wherein the unit of the tire weight is kg, and the unit of the diameter is mm.

2. The tire according to claim 1, characterized in that The ratio, ie tire weight / maximum load-bearing capacity, is less than 0.

013.

3. The tire according to claim 2, characterized in that The ratio, ie tire weight / maximum load-bearing capacity, is less than 0.

012.

4. The tire according to claim 3, characterized in that The ratio, ie tire weight / maximum load-bearing capacity, is less than 0.

011.

5. The tire according to claim 4, characterized in that The ratio, ie tire weight / maximum load-bearing capacity, is less than 0.

010.

6. The tire according to claim 1, characterized in that The number of filaments of the belt cord is 1 or more and 4 or less.

7. The tire according to claim 1, characterized in that The structure of the belt cord is any one of a 1×1 structure, a 1×2 structure, a 1×3 structure, a 1×4 structure or a 2+2 structure.

8. The tire according to claim 1, characterized in that When the tire is viewed in plan from the outer side in the tire radial direction, a crossing angle of the belt cords with respect to the equatorial plane of the tire is less than 25 degrees.

9. The tire according to claim 1, characterized in that The band cord is formed by twisting one yarn, that is, single twist.

10. The tire according to claim 1, wherein: The total fineness of the carcass cords exceeds 2400 dtex.

11. The tire according to claim 1, characterized in that The rubber composition forming the tread contains more than 75 parts by mass of silica per 100 parts by mass of the rubber component.

12. The tire according to claim 1, characterized in that The rubber composition forming the tread has an acetone extractable component, ie, an AE content exceeding 15% by mass.

13. The tire according to claim 1, characterized in that The polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber.

14. The tire according to claim 1, wherein: The rubber composition forming the tread contains vegetable oil.

15. The tire according to claim 1, wherein: The rubber composition forming the tread contains sustainable carbon black.

16. The tire according to claim 1, wherein: The rubber composition forming the tread contains sustainable silica.

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