Tire

Abstract

To improve total performance of low fuel consumption and high-speed durability.SOLUTION: A tire comprises: a carcass comprising a carcass cord; a belt which comprises a belt cord and is provided outside the carcass in a tire radial direction; a band which comprises a band cord and is provided outside the belt in the tire radial direction; and a tread provided outside the band in the tire radial direction. The band cord comprises a polyethylene terephthalate fiber. A ratio of a tire weight (kg) to a maximum load capacity (kg) of the tire, i.e., (the tire weight / the maximum load capacity), is less than 0.014. A product of the tire weight (kg) and a diameter (mm) of the band cord, i.e., (the tire weight×the diameter of the band cord), is less than 4.3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] In a passenger car tire, as in Patent Document 1, generally, a band is provided between a tread and a belt from the viewpoint of preventing deformation of the tire due to centrifugal force generated during high-speed driving and improving high-speed durability.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to improve the overall performance of low fuel consumption and high-speed durability.

Means for Solving the Problems

[0005] The present invention is a carcass including carcass cords, a belt including belt cords and provided on the outer side in the tire radial direction of the carcass, a band including band cords and provided on the outer side in the tire radial direction of the belt, and a tread provided on the outer side in the tire radial direction of the band, wherein the band cords contain polyethylene terephthalate fibers, and 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. The tire is characterized in that the product of the tire weight (kg) and the diameter (mm) of the band cord (tire weight × band cord diameter) is less than 4.3.

Advantages of the Invention

[0006] According to the present invention, it is possible to improve the overall performance of low fuel consumption and high-speed durability.

Brief Description of the Drawings

[0007]

Figure 1

Modes for Carrying Out the Invention

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

[0009] 1. Overview The tire according to the present invention includes a carcass provided with a carcass cord, a belt provided with a belt cord and provided on the outer side in the tire radial direction of the carcass, a band provided with a band cord and provided on the outer side in the tire radial direction of the belt, and a tread provided on the outer side in the tire radial direction of the band. And the band cord contains polyethylene terephthalate fiber (PET fiber). Further, the ratio of the tire weight (kg) to the maximum load capacity (kg) of the tire (tire weight / maximum load capacity) is less than 0.014. Furthermore, the product of the tire weight (kg) and the diameter (mm) of the band cord (tire weight × band cord diameter) is less than 4.3.

[0010] In this specification, the "diameter of the cord" means 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 diameter of a circle (the diameter of the circle assumed when the cross-sectional area is the same).

[0011] By having these characteristics, as will be described later, it is possible to improve the overall performance of low fuel consumption and high-speed durability.

[0012] 2. Mechanism of Effect Expression in the Tire According to the Present Invention Regarding the mechanism of the above-described effect expression in the tire according to the present invention, it is considered as follows.

[0013] Since PET fiber is lighter than nylon 66 (polyamide synthetic fiber), it is considered that by using a band cord containing PET fiber, the weight of the tire can be reduced. Also, since PET fiber has a higher modulus (higher rigidity) than nylon 66 (polyamide synthetic fiber), it is considered that by using a band cord containing PET fiber, the deformation of the tire during running (change in the contact shape) can be suppressed, and high-speed durability can be achieved.

[0014] When the present inventor conducted studies, when controlling the ratio of the tire weight (kg) to the maximum load capacity (kg) of the tire (tire weight / maximum load capacity) to be less than 0.014 and controlling the product of the tire weight (kg) and the diameter (mm) of the band cord (tire weight × diameter of the band cord) to be less than 4.3, it was considered that the overall performance of the low fuel consumption and high-speed durability of the tire could be improved.

[0015] Note that (tire weight / maximum load 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. The lower limit is not particularly limited, but for example, it is preferably more than 0.003, more preferably more than 0.005, and further preferably more than 0.007.

[0016] Further, (tire weight × diameter of belt cord) is more preferably less than 4.0, even more preferably less than 3.5, and even more preferably less than 3.0. The lower limit is not particularly limited, but for example, it is preferably more than 1.5, more preferably more than 2.0, and even more preferably more than 2.5. Note that the tire weight can be reduced by methods such as reducing the fineness of various cords constituting the tire, reducing the thickness of the tread and sidewall, or reducing the density of the rubber composition used for various members constituting the tire.

[0017] [2] More preferred embodiments of the tire according to the present invention The tire according to the present invention can obtain a greater effect by adopting the following embodiments.

[0018] 1. Belt The belt may be one layer, two layers, or three or more layers. The material of the filament constituting the belt is preferably metal, and more preferably iron (steel). The cross-section of the filament constituting the belt may be circular or elliptical, but is preferably circular. Also, it may be corrugated or treated by plating. As the structure of the belt cord, a structure in which the filaments are not twisted may be used, a single twist (1×2, 1×3, 1×4) may be used, or a layer twist (2+2) may be used. In the case of a 1×1 structure, it is preferable to make a cord with one filament untwisted and without corrugation.

[0019] As the belt cord, a steel cord having high rigidity can be preferably used. At this time, the number of filaments of the steel cord is preferably 1 or more and 4 or less. Since the belt cord accounts for a high ratio of the tire weight, by reducing the number of filaments to 4 or less, the belt cord can be further lightened, and further lightening of the tire can be achieved. It is more preferably 2 or more and 3 or less.

[0020] Note that as the structure of the belt cord, it is preferably any one of a 1×1 structure, a 1×2 structure, a 1×3 structure, a 1×4 structure, and a 2+2 structure.

[0021] However, there is a concern that the lightweight belt cord may have a reduced binding force, leading to a decrease in high-speed durability.

[0022] Therefore, in the present invention, when the tire is viewed in a plan view 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. By controlling the crossing angle B to be small in this way, the binding force can be maintained, so it is considered that further improvement can be achieved without causing a decrease in high-speed durability.

[0023] 2. Band The band may be one layer or two layers. The band may be formed across the entire width direction of the tread, or may be formed only at both ends of the tread. However, it is preferable to include both a band formed across the entire width direction of the tread and a band formed only at both ends of the tread.

[0024] The band cord can be composed of fibers such as polyester fibers. As the fibers constituting the band cord, among polyester fibers, PET (polyethylene terephthalate) fibers and PEN (polyethylene naphthalate) fibers are preferable, and PET fibers are more preferable. Also, the fibers constituting the band cord may be fibers recycled from used products or waste products (recycled materials), or may be fibers synthesized from biomass (biomass materials). Furthermore, the band cord may be a hybrid cord using PET fibers and other fibers (such as aramid fibers) in combination.

[0025] As described above, in the present invention, the band cord contains PET fibers, and at this time, it is preferably a PET cord having a single-twist structure obtained by twisting one yarn. By doing so, it is considered that the cord gauge can be reduced while maintaining a high binding force, and further fuel consumption reduction of the tire can be achieved.

[0026] In addition, the diameter of the band cord measured in accordance with 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 or less, more preferably 0.6 mm or less.

[0027] The band can be produced by treating the band cord with an adhesive and then adhering it to a predetermined rubber composition for the band. As the adhesive used for adhesion, for example, EX-313 (glycerin polyglycidyl ether, manufactured by Nagase ChemteX Corporation) and RFL (resorcin formalin-latex) can be used as epoxy compounds.

[0028] As the PET fiber, it may be a sustainable PET fiber, that is, a PET fiber (recycled PET fiber) obtained by collecting and recycling plastic waste such as used plastic bottles (used products and waste materials), or a PET fiber (biomass PET fiber) obtained using biomass as a raw material. Using such sustainable PET fibers is suitable from the viewpoint of environmental protection.

[0029] 3. Carcass The carcass may be either one layer or two layers, but preferably it is one layer. The carcass cord can be composed of fibers. As the fibers constituting the carcass cord, conventionally known fibers such as polyester fibers such as PET (polyethylene terephthalate) fibers and PEN (polyethylene naphthalate) fibers, polyamide fibers such as nylon 6 fibers and nylon 66 fibers, aramid fibers, etc. can be used, and two or more kinds of fibers may be used in combination to form a hybrid cord. The fibers constituting the carcass cord may be fibers recycled from used products or waste products (recycled materials), or may be fibers synthesized from biomass (biomass materials).

[0030] In the present invention, it is preferable that the carcass cord contains fibers of more than 2400 dtex. In the case of a carcass cord with a low total fineness, it is necessary to form a carcass by using two or more layers of cords. However, when using a carcass cord with a high total fineness of more than 2400 dtex, a carcass can be formed with one layer of cord. Therefore, it is considered that the amount of rubber between the layers can be further reduced to further reduce the weight of the tire. It is more preferably 3000 dtex or more, and even more preferably 4000 dtex or more. As the upper limit, it is preferably 5000 dtex or less, more preferably 4800 tex or less, and even more preferably 4600 dtex or less.

[0031] 4. Silica In the present invention, it is preferable that the rubber composition constituting the tread (tire tread rubber composition) contains more than 75 parts by mass of silica with respect to 100 parts by mass of the rubber component. Silica is a reinforcing filler, and it is considered that it can harden the tread and suppress a large change in the tread profile during high-speed driving, so that further improvement in high-speed durability can be achieved. In addition, since silica has OH groups on its surface and can capture ozone, it is considered that the ozone resistance is improved and further improvement in high-speed durability can be achieved also from this aspect. More preferably, it is 80 parts by mass or more, and even more preferably, it is 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.

[0032] At this time, if the particle size (average primary particle size) of silica is too small, the processability deteriorates, so it is preferable to use silica having a particle size of more than 8 nm. More preferably, it is 9 nm or more, and even more preferably, it is 10 nm or more. On the other hand, from the viewpoint of ensuring the reinforcing property of the rubber, it is preferably 25 nm or less, more preferably 20 nm or less, and even more preferably 17 nm or less.

[0033] The average primary particle size of silica means the average value of the values measured by observing the smallest particle unit of silica constituting the aggregated structure as a circle and taking the absolute maximum length of the smallest particle as the diameter of the circle. It can be observed with a transmission or scanning electron microscope, and the primary particles of silica observed in the field of view are measured for 400 or more, and the average value can be obtained by averaging them.

[0034] Specifically, the average primary particle size can be calculated by directly observing the silica taken out from the rubber composition cut out from the tire using an electron microscope or the like, calculating the equivalent cross-sectional diameter from the area of each silica particle obtained, and obtaining the average value. 5. Acetone extract (AE amount)

[0035] In the present invention, the acetone extract content (AE content) 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.

[0036] The acetone extract content (AE content) can be considered as an index indicating the amount of materials that impart plasticity to the rubber component, such as softeners (plasticizers), in the rubber composition, and can also be considered as an index indicating the softness of the rubber composition. Therefore, when the AE content of the tread rubber composition is increased to a certain extent, the tread blocks can be deformed flexibly, and even during high-speed driving, a sufficient contact area with the road surface can be ensured, and heat generation due to concentrated ground pressure can be suppressed. Thus, it is considered that further improvement in high-speed durability can be achieved.

[0037] The measurement of the acetone extract content (AE content) can be carried out in accordance with JIS K 6229:2015. Specifically, by immersing a vulcanized rubber test piece cut out from the measurement site in acetone for a predetermined time and obtaining the mass reduction rate (%) of the test piece, the AE content (% by mass) can be obtained.

[0038] More specifically, under normal temperature and pressure, each vulcanized rubber test piece is immersed in acetone for 72 hours to extract the soluble components, the masses of each test piece before and after extraction are measured, and it can be obtained by the following formula. 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

[0039] Also, the above-mentioned acetone extract content can be appropriately changed by changing the blending ratio of the plasticizer in the rubber composition.

[0040] [3] Embodiments Hereinafter, the present invention will be specifically described based on embodiments.

[0041] 1. Tire according to this embodiment FIG. 1 is a schematic cross-sectional view for explaining the tire according to this embodiment. In FIG. 1, the vertical direction is the radial direction of the tire, the horizontal direction is the rotational axis direction of the tire, and the direction perpendicular to the plane of the paper is the circumferential direction of the tire. In FIG. 1, the dashed-dotted line CL represents the equatorial plane of the tire. Since the shape of this tire is symmetric with respect to the equatorial plane except for the tread pattern, 1 / 4 of the entire tire is shown in FIG. 1.

[0042] As shown in FIG. 1, the tire 1 includes a tread 2, a pair of sidewalls 3, a pair of chafer 4, a pair of beads 5, an inner liner 6, a carcass 7, a belt 8, a pair of fillers 9, and a band 10. The carcass 7, the belt 8, the band 10, and the tread 2 are arranged from the inner side to the outer side in the tire radial direction. Here, the band 10 includes a band cord containing PET fibers. In FIG. 1, the tread 2 is configured with one layer, but it may be configured with two or more layers by providing a cap rubber layer on the outside and a base rubber layer on the inside, or may be configured with three or more layers. The upper limit of the tread thickness is preferably 20 mm or less, and more preferably 15 mm or less.

[0043] With such a configuration, by appropriately controlling (tire weight / maximum load capacity) and (tire weight × diameter of the band cord) as described above, it is possible to improve the overall performance of low fuel consumption and high-speed durability.

[0044] 2. Rubber composition for tread In this embodiment, the rubber composition for the tread can be obtained by kneading various compounding materials such as a rubber component, a reinforcing material, an antioxidant, an oil, a resin material, and an antioxidant.

[0045] (1) Compounding materials (a) Rubber component The rubber component is not particularly limited. For example, diene rubbers such as isoprene rubbers (natural rubber (NR), isoprene rubber (IR), etc.), styrene-butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR) can be used. These may be used alone or in combination of two or more. In the present invention, the combined use of NR, SBR, and BR is preferred.

[0046] (i) SBR The weight-average molecular weight of SBR is, for example, more than 100,000 and less than 2,000,000. The styrene content of SBR is preferably, for example, more than 5% by mass, more preferably more than 10% by mass, and even more preferably more than 15% by mass. On the other hand, it is preferably less than 40% by mass, more preferably less than 35% by mass, and even more preferably less than 30% by mass. The vinyl content (amount of 1,2-bonded butadiene units) of SBR is preferably, for example, more than 5% by mass, more preferably more than 10% by mass, and even more preferably more than 15% by mass. On the other hand, it is preferably less than 70% by mass, more preferably less than 40% by mass, and even more preferably less than 30% by mass. The structure identification of SBR (measurement of styrene content and vinyl content) can be performed, for example, using an apparatus of the JNM-ECA series manufactured by JEOL Ltd.

[0047] SBR is not particularly limited. For example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc. can be used. SBR may be either non-modified SBR or modified SBR. Further, hydrogenated SBR in which the butadiene part in SBR is hydrogenated may be used. The hydrogenated SBR may be obtained by post-hydrogenation treatment of the BR part in SBR, or a similar structure may be obtained by copolymerizing styrene, ethylene, and butadiene.

[0048] The modified SBR preferably has a functional group that interacts with a filler such as silica. For example, a terminally modified SBR (a terminally modified SBR having the above functional group at the terminal), which is obtained by modifying at least one terminal of SBR with a compound (modifying agent) having the above functional group, a main-chain modified SBR having the above functional group in the main chain, a main-chain terminally modified SBR having the above functional group in the main chain and at the terminal (for example, a main-chain terminally modified SBR having the above functional group in the main chain and at least one terminal modified with the above modifying agent), or a terminally modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or an epoxy group introduced therein can be mentioned.

[0049] Examples of the above functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, an epoxy group, etc. These functional groups may have a substituent.

[0050] As the modified SBR, for example, an SBR modified with a compound (modifying agent) represented by the following formula can be used.

[0051]

Chemical formula

[0052] In the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH) or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R 4 and R5 may combine to form a ring structure together with a nitrogen atom. n represents an integer.

[0053] As the modified SBR modified with the compound (modifying agent) represented by the above formula, SBR in which the polymerization terminal (active terminal) of solution-polymerized styrene-butadiene rubber (S-SBR) is modified with the compound represented by the above formula (modified SBR described in JP-A-2010-111753, etc.) can be used.

[0054] R 1 、R 2 and R 3 are preferably alkoxy groups (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). R 4 and R 5 are preferably alkyl groups (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Further, when R 4 and R 5 combine to form a ring structure together with a nitrogen atom, a 4- to 8-membered ring is preferred. The alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0055] Specific examples of the above modifying agent include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. These may be used alone or in combination of two or more.

[0056] In addition, as the modified SBR, modified SBR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenolic groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, and N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide and other sulfide group-containing silane compounds; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-t-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; in addition, N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethyl ethyleneurea, 1,3-divinyl ethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone and the like can be mentioned. The modification with the above compound (modifying agent) can be carried out by a known method.;

[0057] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., ENEOS MATERIALS Co., Ltd., Asahi Kasei Co., Ltd., Zeon Corporation, etc. can be used. The SBR may be used alone or in combination of two or more kinds.;

[0058] 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 still more 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 still more preferably 60 parts by mass or less.;

[0059] (b) Isoprene rubber Examples of the isoprene rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, etc. NR is preferred in terms of excellent strength.;

[0060] As the NR, for example, those commonly used in the tire industry such as SVR-L, SIR20, RSS#3, TSR20, etc. can be used. The IR is not particularly limited, and for example, those commonly used in the tire industry such as IR2200 manufactured by Nippon Zeon Co., Ltd. can be used. As the modified NR, deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc., as the modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc., as the modified IR, epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. can be mentioned. These may be used alone or in combination of two or more.

[0061] The content of the isoprene-based 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.

[0062] (C) BR The weight-average molecular weight of the BR is, for example, more than 100,000 and less than 2,000,000. The vinyl content of the BR is, for example, more than 1% by mass and less than 30% by mass. The cis content of the BR is, for example, more than 1% by mass and 98% by mass or less. The trans content of the BR is, for example, more than 1% by mass and less than 60% by mass. The cis content can be measured by infrared absorption spectroscopy.

[0063] The BR is not particularly limited, and BR with a high cis content (cis content of 90% or more), BR with a low cis content, BR containing syndiotactic polybutadiene crystals, etc. can be used. The BR may be either unmodified BR or modified BR, and as the modified BR, for example, BR modified with a compound (modifying agent) represented by the following formula can be used.

[0064] [Chemical formula]

[0065] In the formula, R 1 , R 2and R 3 is, independently or identically, an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH) or a derivative thereof. R 4 and R 5 is, independently or identically, a hydrogen atom or an alkyl group. R 4 and R 5 may combine to form a ring structure together with the nitrogen atom. n represents an integer.

[0066] Examples of the modified BR modified by the compound (modifying agent) represented by the above formula include BR in which the polymerization terminal (active terminal) is modified by the compound represented by the above formula.

[0067] R 1 、R 2 and R 3 are preferably alkoxy groups (preferably alkoxy groups having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). R 4 and R 5 are preferably alkyl groups (preferably alkyl groups having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Further, when R 4 and R 5 combine to form a ring structure together with the nitrogen atom, it is preferably a 4- to 8-membered ring. The alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0068] Specific examples of the above modifying agent include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane and the like. These may be used alone or in combination of two or more.

[0069] In addition, as the modified BR, modified BR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenolic groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine, 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide and other sulfide group-containing silane compounds; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-t-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; in addition to N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethyl ethyleneurea, 1,3-divinyl ethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone and the like can be mentioned. Incidentally, the modification by the above compounds (modifying agents) can be carried out by known methods. These modified BRs may be used alone or in combination of two or more kinds.;

[0070] As BR, for example, products of Ube Industries, Ltd., ENEOS MATERIALS Co., Ltd., Asahi Kasei Corporation, Nippon Zeon Co., Ltd. and the like can be used.

[0071] The content of BR in 100 parts by mass of the rubber component is preferably 25 parts by mass or more, and more preferably 30 parts by mass or more. On the other hand, it is preferably 40 parts by mass or less, and more preferably 35 parts by mass or less.

[0072] (ii) Other rubber components The rubber composition may contain, as other rubber components, rubber (polymer) generally used in the production of tires such as nitrile rubber (NBR) as required.

[0073] Note that the raw materials (monomers) of synthetic rubbers such as SBR and BR described above may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires and non-rubber products such as polystyrene.

[0074] The monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include isoprene derived from recycling, butadiene derived from recycling, and aromatic vinyl derived from recycling. Examples of the butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited, and examples include styrene. Among them, it is preferable to use isoprene derived from recycling (recycled isoprene), butadiene (recycled butadiene), and / or styrene derived from recycling (recycled styrene) as raw materials.

[0075] The method for producing recycled monomers is not particularly limited, and examples include being synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Also, the method for producing recycled naphtha is not particularly limited, and for example, rubber products such as tires may be decomposed under high temperature and high pressure, decomposed by microwaves, or extracted after mechanical pulverization.

[0076] Furthermore, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. The biomass is not particularly limited, and examples include agricultural and forestry products, sugars, wood chips, plant residues after obtaining useful components, ethanol derived from plants, biomass naphtha, and the like.

[0077] The biomass-derived monomers (biomass monomers) are not particularly limited, and examples thereof include biomass-derived butadiene and biomass-derived aromatic vinyls. Examples of the butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited, and examples thereof include styrene. Further, the method for producing the biomass monomer is not particularly limited, and examples thereof include those by biological and / or chemical and / or physical conversion of animals and plants. Fermentation by microorganisms is typical as the biological conversion, and examples of the chemical and / or physical conversion include those by a catalyst, high heat, high pressure, electromagnetic waves, a critical liquid, and combinations thereof.

[0078] The polymers synthesized from the biomass monomer components (biomass polymers) are not particularly limited, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene and aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyls. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0079] Whether the raw material of the polymer is derived from biomass can be determined by pMC (percent Modern Carbon) measured in accordance with ASTM D6866-10.

[0080] pMC is the ratio of the 14 C concentration of the sample to the 14 C concentration of the standard modern carbon (modern standard reference), and is a value used as an index indicating the biomass ratio of a compound. The significance of this value will be described below.

[0081] In one mole (6.02×10 23 pieces) of carbon atoms, there are about 6.02×10 11 pieces, which is about one trillionth of ordinary carbon atoms, of 14C exists. 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 these to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken up and fixed by plants and the like, in fossil fuels such as coal, oil, and natural gas where more than 226,000 years are considered to have passed, at the beginning of fixation, it was also included in these. 14 All of the C element has decayed. Therefore, in the current 21st century, in fossil fuels such as coal, oil, and natural gas 14 The C element is not contained at all. Therefore, in chemical substances produced using these fossil fuels as raw materials 14 The C element is not contained at all.

[0082] On the other hand, 14 C is constantly generated by nuclear reactions of cosmic rays in the atmosphere, and is in balance with the decrease due to radioactive decay. In the earth's atmospheric environment, 14 The amount of C is a certain amount. Therefore, in substances derived from biomass resources that are circulating in the current environment 14 The C concentration is about 1×10 -12 mol% with respect to the entire C atoms as described above. Therefore, by using the difference between these values, the biomass ratio in a certain compound can be calculated.

[0083] This 14 C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 C) is measured. In the measurement, 14 As a modern standard reference for the concentration of C, in the circulating carbon in nature at the time of 1950 14The C concentration is adopted. 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 (radioactivity intensity of 14 C per 1 g of carbon) is separated for each carbon isotope, 13 For 14 C, it is corrected to a constant value, and the value after decay correction from 1950 AD to the measurement date is used as the value of the standard

[0084] C concentration (100%). The ratio of this value to the value of the actually measured sample is the pMC value. 14 Therefore, if the rubber is made of 100% biomass-derived substances, although there are regional differences, etc., it usually does not reach 100 under normal conditions at present, so it will show a value of about 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring this

[0085] C concentration, it will show a value of about 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% mentioned above.

[0086] (b) Blending materials other than the rubber component (i) Filler The rubber composition preferably contains silica or carbon black as a reinforcing agent. If necessary, it may also contain other fillers, such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, vulcanized rubber particles (rubber powder), etc. When using silica, it is preferably used in combination with a silane coupling agent.

[0087] As the compounding amount of the filler, it is preferable to contain at least more than 75 parts by mass of silica with respect to 100 parts by mass of the rubber component. However, the total compounding amount with other fillers is preferably 80 parts by mass or more, more preferably 90 parts by mass or more with respect to 100 parts by mass of the rubber component. On the other hand, from the viewpoint of dispersibility in the rubber composition, it is preferably 150 parts by mass or less, more preferably 100 parts by mass or less.

[0088] (i) silica 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 improved. And by containing more than 75 parts by mass, hydrogen bonds are generated between the silica surfaces and also interact with the rubber component. Therefore, during driving, it is easy to generate and transmit force inside the rubber, and it is easy to transmit the force generated during turning, and excellent handling stability can be ensured.

[0089] 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. The above-mentioned BET specific surface area is the value of N2SA measured by the BET method in accordance with ASTM D3037-93.

[0090] Silica is not particularly limited. For example, silica prepared by the dry method (anhydrous silica), silica prepared by the wet method (hydrous silica), etc., which are common in the tire industry, 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.

[0091] The raw material for silica is not particularly limited. For example, it may be a raw material derived from minerals such as quartz, or a raw material derived from organisms such as rice husks (for example, silica obtained from biomass materials such as rice husks), or silica recycled from products containing silica may also be used. Among them, hydrated silica prepared by the wet method is preferred because it has many silanol groups. These silicas may be used alone or in combination of two or more.

[0092] Silica made from biomass materials (biomass silica) can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same way as conventional wet silica to precipitate silicon dioxide, followed by filtration, washing with water, drying, and pulverization.

[0093] Silica recycled from products containing silica (recycled silica) can be used, for example, silica recovered from products containing silica such as electronic components such as semiconductors, tires, desiccants, and filter materials such as diatomaceous earth. Also, the recovery method is not particularly limited, and examples include pyrolysis and decomposition by electromagnetic waves. Among them, silica recovered from electronic components such as semiconductors or tires is preferred.

[0094] When silica crystallizes, it is insoluble in water and the silicic acid, which is its component, cannot be utilized. By controlling the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (see, for example, Japanese Patent Application Laid-Open No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, p. 216-222, etc.).

[0095] Amorphous silica extracted from rice husks can be commercially available products from Wilmar and others.

[0096] These silicas may be used alone or in combination of two or more. It is preferable from the viewpoint of environmental protection to use sustainable silicas such as biomass silica obtained from biomass as a raw material, recycled silica obtained from recycling of used products or waste materials, and the like.

[0097] As described above, the content of silica with respect to 100 parts by mass of the rubber component is preferably more than 75 parts by mass, more preferably 80 parts by mass or more, and even more preferably 90 parts by mass or more with respect to 100 parts by mass of the rubber component. As the upper limit, for example, it is preferably 150 parts by mass or less, and more preferably 100 parts by mass or less.

[0098] (ii) Silane coupling agent When using silica, it is preferable to use a silane coupling agent in combination in order to enhance the dispersibility of silica and to improve mechanical properties and moldability by reaction with silica.

[0099] The silane coupling agent is not particularly limited. For example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, etc. sulfide-based, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, mercapto-based such as NXT and NXT-Z manufactured by Momentive, vinyl-based such as vinyltriethoxysilane and vinyltrimethoxysilane, amino-based such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane, glycidoxy-based such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, nitro-based such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, chloro-based such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane, etc. can be mentioned. Among these, silane coupling agents having a thiocarbonyl group such as the above-mentioned NXT are preferred. These may be used alone or in combination of two or more.

[0100] As the silane coupling agent, for example, products of Evonik Industries, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Toray Dow Corning Co., Ltd. etc. can be used.

[0101] The content of the silane coupling agent is preferably more than, for example, 3 parts by mass, more preferably 5 parts by mass or more, and still more preferably 7 parts by mass or more with respect to 100 parts by mass of silica. As the upper limit, it is preferably less than, for example, 15 parts by mass, more preferably 12 parts by mass or less, and still more preferably 9 parts by mass or less.

[0102] (iii) Carbon black Carbon black is preferably used for the purpose of improving the crack growth resistance, durability, ultraviolet degradation resistance, etc. of the tire.

[0103] The nitrogen adsorption specific surface area (N2SA) of carbon black is, from the viewpoint of the reinforcing property to rubber, 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 viewpoint 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. The nitrogen adsorption specific surface area of carbon black is measured according to ASTM D4820-93.

[0104] The dibutyl phthalate (DBP) absorption amount of carbon black is, from the viewpoint of the rigidity of rubber, for example, preferably 50 ml / 100 g or more, more preferably 100 ml / 100 g or more. On the other hand, from the viewpoint of the followability to the deformation of rubber, it is preferably 250 ml / 100 g or less, more preferably 150 ml / 100 g or less. The DBP absorption amount of carbon black is measured according to ASTM D2414-93.

[0105] The carbon black is not particularly limited, and examples include furnace black (furnace carbon black) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal black (thermal carbon black) such as FT and MT; channel black (channel carbon black) such as EPC, MPC, and CC. In addition, examples of the product numbers include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. These may be used alone or in combination of two or more.

[0106] In addition to mineral oil, the raw material of carbon black may 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. It is preferable from the viewpoint of environmental protection to use sustainable carbon black such as biomass carbon black using biomass materials as raw materials or recycled carbon black using recycled materials such as used products and waste materials as raw materials.

[0107] Also, the production method of carbon black may be by combustion such as the furnace method, by hydrothermal carbonization (HTC), or by thermal decomposition of methane by the thermal black method or the like.

[0108] As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., Columbian Carbon Company, etc. can be used. These may be used alone or in combination of two or more.

[0109] 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.

[0110] (iv) Other fillers In addition to the above-mentioned carbon black and silica, the rubber composition may further contain fillers generally used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, magnesium sulfate, etc. The content of these is, for example, more than 0.1 part by mass and less than 150 parts by mass with respect to 100 parts by mass of the rubber component.

[0111] (B) Softening agent (plasticizer) component In the rubber composition, from the viewpoint of imparting plasticity to the rubber component and appropriately dispersing the powder material during kneading, it is preferable to use a softening agent (plasticizer) component as necessary. Here, the softening agent component is a concept including both softening agents that are liquid at 25°C and softening agents that are solid at 25°C.

[0112] Examples of softening agents include resin components, oils, liquid polymers, ester-based plasticizers, etc. These softening agents may be derived from mineral resources such as petroleum and natural gas, may be derived from biomass, or may be derived from naphtha recycled from rubber products or non-rubber products. Also, low-molecular-weight hydrocarbon components obtained by pyrolyzing and extracting used tires and products containing various components may be used as softening agents. Among these, softening agents derived from biomass or recycling are preferable as sustainable softening agents.

[0113] These softeners may be used alone or in combination of two or more. The content of the softener component relative to 100 parts by mass of the rubber component is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and still more preferably 25 parts by mass or more. The upper limit is preferably, for example, 40 parts by mass or less, more preferably 35 parts by mass or less, and still more preferably 30 parts by mass or less. Note that the content of the softener component includes the amount of oil contained in rubber (oil-extended rubber) and the like.

[0114] (i) Oil Examples of the oil include mineral oil, vegetable oil, and animal oil. From the perspective of life cycle assessment, waste oil used in a rubber mixer or an engine, or refined waste cooking oil used in a restaurant may also be used.

[0115] (i-1) Mineral oil In this specification, the mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of the mineral oil include paraffinic oil (mineral oil), naphthenic oil, and aromatic oil.

[0116] Specific examples of the mineral oil include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), and the like.

[0117] In addition, oil with a low content of polycyclic aromatic (PCA) compounds can also be used for environmental protection. Examples of the low-PCA-content oil include MES, TDAE, and heavy naphthenic oil.

[0118] Examples of commercially available mineral oils include oils such as paraffinic, aromatic, and naphthenic oils. For example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Oleosuisse, H&R, Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kogyo Co., Ltd., etc. can be used. These may be used alone or in combination of two or more.

[0119] (i-2) Vegetable oil Examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc.

[0120] Furthermore, examples of vegetable oils include refined oils (such as salad oil) obtained by refining each of the above oils, transesterified oils obtained by transesterification, hydrogenated hardened oils, thermally polymerized oils obtained by thermal polymerization, oxidation polymerized oils obtained by oxidation, and waste cooking oils recovered from those used as edible oils, etc. Note that vegetable oils may be liquid or solid at normal temperature (25°C). These may be used alone or in combination of two or more.

[0121] Vegetable oils preferably contain acylglycerol, and more preferably contain triacylglycerol. Note that acylglycerol refers to a compound in which the hydroxy group of glycerin and a fatty acid are ester-bonded. Acylglycerol is not particularly limited, and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, or a multimer of three or more. Note that acylglycerols of two or more can be obtained by thermal polymerization, oxidation polymerization, etc. Also, acylglycerol may be liquid or solid at normal temperature (25°C).

[0122] As a method for confirming whether acylglycerol is contained in the rubber composition, it is not particularly limited, but 1 it can be confirmed by 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours. After removing the rubber composition, at room temperature 1 1H-NMR is measured. When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals are observed around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm. Since these signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group, the content of acylglycerol can be confirmed. Here, "around" refers to a range of ±0.10 ppm.

[0123] The fatty acid is not particularly limited and may be an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0124] Among them, as the fatty acid, it is desirable to contain a fatty acid with few double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As the vegetable oil containing such a fatty acid, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid may be used, or a vegetable oil subjected to modification such as transesterification may be used. In addition, in order to produce a vegetable oil containing such a fatty acid, plants may be improved by variety improvement, genetic recombination, genome editing, etc.

[0125] As the vegetable oil, for example, those commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Oryz Oy, H&R, Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0126] (ii) Liquid rubber Liquid rubber is a polymer in a liquid state at room temperature (25°C) and is a rubber component that can be extracted from a vulcanized tire by acetone extraction. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and hydrogenated products thereof.

[0127] A farnesene-based polymer is a polymer obtained by polymerizing farnesene and has a structural unit based on farnesene. Farnesene has isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene).

[0128] The farnesene-based polymer may be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

[0129] Examples of liquid diene-based polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), and the like.

[0130] The liquid diene-based polymer has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of, for example, more than 1.0×10 3 super, 2.0×10 5 less than. Here, the Mw of the liquid diene-based polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0131] As the liquid rubber, for example, products of Kuraray Co., Ltd., KRAIBURG Co., etc. can be used.

[0132] (iii) Resin component The rubber composition for tread preferably contains a resin component. When the resin component is contained in the rubber composition, the adhesiveness of the resin component improves the ground contact property with the road surface, so it is considered that the rolling resistance during starting can be further reduced.

[0133] The resin component also functions as an adhesiveness-imparting component and may be solid or liquid at normal temperature. Specific resin components include, for example, rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc., and two or more of them may be used in combination. In addition, these resin components may be provided with a modifying group capable of reacting with silica or the like as necessary. And the content with respect to 100 parts by mass of the rubber component is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and still more preferably 50 parts by mass or more.

[0134] The rosin-based resin is a resin mainly composed of rosin acid obtained by processing pine resin. This rosin-based resin (rosins) can be classified according to the presence or absence of modification, and can be classified into unmodified rosin (non-modified rosin) and rosin modified body (rosin derivative). Examples of unmodified rosin include tall rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Rosin modified bodies are modified bodies of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid-modified rosins, unsaturated carboxylic acid-modified rosin esters, amide compounds of rosin, and amine salts of rosin.

[0135] Styrene resins are polymers using styrene monomers as constituent monomers, and examples include polymers polymerized with styrene monomers as the main component (50% by mass or more). Specifically, homopolymers obtained by polymerizing styrene monomers (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.) alone, copolymers obtained by copolymerizing two or more styrene monomers, and copolymers of styrene monomers and other monomers copolymerizable therewith are also included.

[0136] Examples of the other monomers include acrylonitriles such as acrylonitrile and methacrylonitrile, acrylics, unsaturated carboxylic acids such as methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene and butadiene isoprene, olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or acid anhydrides thereof; and the like.

[0137] Among coumarone resins, coumarone-indene resins are preferred. Coumarone-indene resins are resins containing coumarone and indene as monomer components constituting the resin skeleton (main chain). Examples of monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methyl indene, vinyl toluene, and the like.

[0138] The hydroxyl value (OH value) of the coumarone-indene resin is, for example, more than 15 mgKOH / g and less than 150 mgKOH / g. The OH value represents the amount of potassium hydroxide in milligrams required to neutralize acetic acid bonded to hydroxyl groups when 1 g of the resin is acetylated, and is a value measured by the potentiometric titration method (JIS K 0070:1992).

[0139] The softening point of the coumarone-indene resin is, for example, over 30°C and less than 160°C. The softening point is the temperature at which the ball drops when measured with a ring and ball softening point measuring device according to the softening point specified in JIS K 6220-1:2001.

[0140] Examples of terpene resins include polyterpene, terpene phenol, and aromatic-modified terpene resins. Polyterpene is a resin obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are hydrocarbons represented by the composition of (C5H8) n and their oxygen-containing derivatives, and are compounds having a terpene as a basic skeleton, which are classified into monoterpene (C 10 H 16 ), sesquiterpene (C 15 H 24 ), diterpene (C 20 H 32 ), etc. Examples thereof include α-pinene, β-pinene, dipentene, limonene, myrcene, allo-ocimene, ocimene, α-farnesene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc.

[0141] Examples of polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin, which are made from the above-mentioned terpene compounds as raw materials, as well as hydrogenated terpene resins obtained by hydrogenating the terpene resins. Examples of terpene phenols include resins obtained by copolymerizing the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating such resins. Specifically, examples include resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds, and formalin. Examples of phenolic compounds include phenol, bisphenol A, cresol, and xylenol. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating such resins. The aromatic compound is not particularly limited as long as it has an aromatic ring. Examples include phenolic compounds such as phenol, alkylphenol, alkoxyphenol, and unsaturated hydrocarbon group-containing phenol; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, and unsaturated hydrocarbon group-containing naphthol; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and unsaturated hydrocarbon group-containing styrene; and coumarone and indene.

[0142] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of the C5 fraction include petroleum fractions equivalent to 4 to 5 carbon atoms, such as cyclopentadiene, pentene, pentadiene, and isoprene. As the C5-based petroleum resin, dicyclopentadiene resin (DCPD resin) is preferably used.

[0143] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, which may be hydrogenated or modified. Examples of the C9 fraction include petroleum fractions corresponding to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, and methylindene. As specific examples, for instance, coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl-based resins are preferably used. Among the aromatic vinyl-based resins, due to economic reasons, ease of processing, and excellent heat generation properties, a homopolymer of α-methylstyrene (AMS resin) or styrene, or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred. As the aromatic vinyl-based resin, for example, those commercially available from companies such as Kraton Corporation and Eastman Chemical Company can be used.

[0144] "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, which may be hydrogenated or modified. Examples of the C5 fraction and the C9 fraction include the above-mentioned petroleum fractions. As the C5C9 resin, for example, those commercially available from Tosoh Corporation, LUHUA, etc. can be used.

[0145] The acrylic resin is not particularly limited, and for example, a solvent-free acrylic resin can be used.

[0146] The solvent-free acrylic resin is a (meth)acrylic resin (polymer) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (the methods described in U.S. Patent No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Patent No. 5,010,166, TREND 2000, No. 3, p42-45 of the Annual Report of Toagosei Co., Ltd., etc.) without using a polymerization initiator, a chain transfer agent, an organic solvent, etc. as auxiliary raw materials as much as possible. In the present invention, "(meth)acrylic" means methacrylic and acrylic.

[0147] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (such as alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0148] In addition, as the monomer components constituting the acrylic resin, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or (meth)acrylic acid derivatives.

[0149] The acrylic resin may be a resin composed only of the (meth)acrylic component or a resin having components other than the (meth)acrylic component as constituent elements. Further, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, etc.

[0150] Examples of the resin component include products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Clayton, Nippon Paint Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., Tago Chemical Industry Co., Ltd., etc.

[0151] (C) Wax The rubber composition may contain wax. The content of the wax is preferably, for example, 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, and even more preferably 1.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0152] The wax is not particularly limited, and any wax commonly used in the tire industry can be preferably used. For example, mineral waxes, plant-derived waxes, etc. can be mentioned. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among them, mineral waxes are preferred.

[0153] Examples of plant-derived waxes include rice wax, carnauba wax, candelilla wax, etc. Examples of mineral waxes include paraffin wax, microcrystalline wax, these selected special waxes, etc., and paraffin wax is preferred. In the present invention, the wax shall not contain stearic acid.

[0154] As the wax, for example, those commercially available from Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramoelt Co., etc. can be used. These waxes may be used alone or in combination of two or more.

[0155] (ii) Antioxidant The rubber composition may contain an antioxidant. The content of the antioxidant is, for example, more than 1 part by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0156] The anti-aging agent is not particularly limited, but examples include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine-based anti-aging agents 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'-ditoly-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; bis, tris, polyphenol-based anti-aging agents such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among them, p-phenylenediamine-based anti-aging agents and quinoline-based anti-aging agents are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. These may be used alone or in combination of two or more kinds.

[0157] As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Industry Co., Ltd., Flexsys, etc. can be used.

[0158] (Co) processing aid The rubber composition may contain a processing aid. Examples of the processing aid include metal salts (compounds in which the hydrogen atom of an acid is replaced by a metal ion), fatty acid amides, amide esters, fatty acid esters, etc. These may be used alone or in combination of two or more kinds. Among them, metal salts and fatty acid amides are preferred, and metal salts are more preferred.

[0159] 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. Further, magnesium, zinc, nickel, molybdenum, etc. can also be used. Among them, alkali metals are preferred.

[0160] Examples of the acid used in the metal salt include fatty acids such as lauric acid, myristic acid, palmitic acid, etc. Further, boric acid, carbonic acid, hydrochloric acid, nitric acid, sulfuric acid, etc. can also be used.

[0161] As commercially available products of the processing aid, products of Kinoshita Chemical Co., Ltd., Ken-ei Pharmaceutical Co., Ltd., Struktol, Performance Additives, etc. can be used.

[0162] The content of the processing aid is preferably 1 part by mass or more, more preferably 2 parts by mass or more, based on 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.

[0163] (f) Lubricant (Stearic acid) The rubber composition may contain a lubricant. As the lubricant, lubricants based on fatty acid derivatives such as stearic acid can be preferably used. As stearic acid, conventionally known ones can be used, specifically, for example, products of NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Corporation, Chiba Fatty Acids Co., Ltd., etc. can be used. Further, Struktol WB16 manufactured by Struktol can also be used.

[0164] The content of stearic acid is preferably more than 0.5 part by mass and less than 10.0 parts by mass, based on 100 parts by mass of the rubber component.

[0165] (t) Zinc oxide The rubber composition may contain zinc oxide. The content of zinc oxide is, for example, more than 0.5 part by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component. As the zinc oxide, conventionally known ones can be used, for example, products of Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusuitech Co., Ltd., Sho-Doh Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0166] (D) Crosslinking agent and vulcanization accelerator The rubber composition preferably contains a crosslinking agent such as sulfur. The content of the crosslinking agent is, for example, more than 0.1 part by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component. Note that the sulfur content is the pure sulfur content, and when insoluble sulfur is used, it is the content excluding the oil content.

[0167] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc. generally used in the rubber industry. These may be used alone or in combination of two or more.

[0168] As sulfur, for example, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexsys, Nippon Kankyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0169] Crosslinking agents other than sulfur may be used. Specifically, for example, Tackiol V200 manufactured by Tago Chemical Industry Co., Ltd., DURALINK HTS (sodium 1,6 - hexamethylene - dithiolsulfate dihydrate) manufactured by Flexsys, KA9188 (1,6 - bis(N,N’ - dibenzylthiocarbamoyldithio)hexane: hybrid crosslinking agent) manufactured by Lanxess, etc., vulcanizing agents containing sulfur atoms, organic peroxides such as dicumyl peroxide, etc. can be used.

[0170] And the rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, more than 0.3 part by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0171] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyldisulfide, and N-cyclohexyl-2-benzothiazylsulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-t-butyl-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diorthotolylguanidine, and orthotolylbiguanidine. These may be used alone or in combination of two or more.

[0172] (V) Others In addition to the above components, the rubber composition may be blended with additives generally used in the tire industry, such as organic fillers such as cellulose fibers and organic peroxides, as necessary. The content of these additives is, for example, more than 0.1 part by mass and less than 50 parts by mass with respect to 100 parts by mass of the rubber component.

[0173] In the present invention, among the above-described various materials, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, anti-aging agent, surfactant, etc.) may be derived from carbon dioxide in the atmosphere. As a method for obtaining the formulation of the present invention from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation step of synthesizing methane from carbon dioxide may be converted.

[0174] (2) Preparation of rubber composition The rubber composition It can be produced by a manufacturing method including a base kneading step of kneading a rubber component and a filler such as silica, and a finishing kneading step of kneading the kneaded product obtained in the base kneading step and a crosslinking agent.

[0175] Kneading can be carried out using a known (closed-type) kneader such as a Banbury mixer, a kneader, an open roll, etc.

[0176] The kneading temperature in the base kneading step is, for example, above 50°C and below 200°C, and the kneading time is, for example, above 30 seconds and below 30 minutes. In the base kneading step, in addition to the above components, compounding agents conventionally used in the rubber industry, such as softening agents such as oil, stearic acid, zinc oxide, anti-aging agents, waxes, vulcanization accelerators, etc., may be appropriately added and kneaded as required.

[0177] In the finishing kneading step, the kneaded product obtained in the base kneading step and a crosslinking agent are kneaded. The kneading temperature in the finishing kneading step is, for example, above room temperature and below 80°C, and the kneading time is, for example, above 1 minute and below 15 minutes. In the finishing kneading step, in addition to the above components, vulcanization accelerators, zinc oxide, etc. may be appropriately added and kneaded as required.

[0178] The rubber composition obtained as above can then be formed into a tread by extrusion into a predetermined shape.

[0179] 3. Manufacture of tires The tire according to this embodiment can be manufactured by a normal method. First, using the rubber composition obtained as above, it is formed into a predetermined shape to manufacture a tread. Next, it is combined with other rubber members on a tire molding machine to produce an unvulcanized tire.

[0180] Specifically, on the forming drum, an inner liner as a member for ensuring the airtightness of the tire, a carcass as a member for withstanding the load, impact, and inflation pressure received by the tire, a belt member as a member for strongly clamping the carcass to increase the rigidity of the tread, a band, etc. are wound, both ends of the carcass are fixed to both side edges, and a bead portion as a member for fixing the tire to the rim is arranged. After forming into a toroidal shape, a tread is attached to the central portion of the outer periphery, and a sidewall is bonded to the radially outer side to form a side portion, thereby producing an unvulcanized tire.

[0181] Thereafter, the unvulcanized tire produced as described above is heated and pressurized in a vulcanizer to obtain a tire. The vulcanization process can be carried out by applying known vulcanization means. The vulcanization temperature is, for example, above 120°C and below 200°C, and the vulcanization time is, for example, above 5 minutes and below 15 minutes.

[0182] As described above, the tire obtained can improve the comprehensive performance of low fuel consumption and high-speed durability by appropriately controlling the product of the tire weight (kg) and the diameter (mm) of the band cord, so that the effect of using the PET band and the effect of the appropriately formed tire weight (the ratio of the tire weight to the maximum load capacity) cooperate with each other.

[0183] And the tire according to the present invention can be preferably used as a passenger car tire, a large passenger car tire, a large SUV tire, a truck and bus tire, a two-wheeler tire, a racing tire, a studless tire (winter tire), an all-season tire, a run-flat tire, etc., and particularly preferably as a passenger car tire.

Examples

[0184] Hereinafter, examples (Examples) considered to be preferable when implementing are shown, but the scope of the present invention is not limited to the said examples.

[0185] A tire formed from various compounding materials shown below, and a tire (tire size: 195 / 65R15) composed of tire members such as bands and belts are considered, and the results calculated based on the evaluation methods described later regarding low fuel consumption and high-speed durability are shown together at the bottom of Table 2 and Table 3.

[0186] 1. Preparation of rubber composition Using various compounding materials shown below, a tread rubber composition is prepared.

[0187] (1) Compounding materials (a) Rubber components (i) NR: TSR20 (ii) SBR-1: Modified S-SBR (styrene content: 25% by mass, vinyl content: 63 mol%, Tg: -20°C, non-oil product) manufactured based on Production Example 1 described later (iii) SBR-2: Modified S-SBR (styrene content: 24% by mass, vinyl content: 59 mol%, Tg: -25°C, non-oil product) manufactured based on Production Example 2 described later (iv) SBR-3: HPR840 manufactured by ENEOS MATERIALS Co., Ltd. (modified S-SBR, styrene content: 10% by mass, vinyl content: 42 mol%, Tg: -60°C, non-oil product) (v) BR-1: BR730 manufactured by ENEOS MATERIALS Co., Ltd. (cis content: 96% by mass, trans content: 3% by mass, vinyl content: 1% by mass) (vi) BR-2: ASAPREN N103 manufactured by Asahi Kasei Corporation (cis content: 38% by mass, Tg: -90°C) (vii) BR-3: BR360B manufactured by Ube Industries, Ltd. (cis content: 97% by mass, trans content: 1% by mass, vinyl content: 2% by mass)

[0188] (Production Example 1) The above SBR-1 is prepared according to the following procedure. First, cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene are charged into a nitrogen-substituted autoclave reactor. After adjusting the temperature of the contents of the reactor, n-butyllithium is added to initiate polymerization. Then, polymerization is carried out under adiabatic conditions. When the polymerization conversion rate reaches 99%, 1,3-butadiene is added, and polymerization is carried out for an additional 5 minutes. N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane is added as a modifier to conduct the reaction. After the polymerization reaction is completed, 2,6-di-tert-butyl-p-cresol is added, solvent is removed by steam stripping, and drying is carried out using a hot roll to obtain SBR-1.

[0189] (Production Example 2) The above SBR-2 is obtained in the same manner as in Production Example 1, except that the target styrene content, vinyl content, and Tg are changed, and the modifier is 3-dimethylaminopropyltriethoxysilane.

[0190] (b) Compounding materials other than the rubber component (i) Carbon black: Dia Black N220 manufactured by Mitsubishi Chemical Corporation (N2SA: 115 m 2 / g) (ii) Silica: Ultrasil VN3 manufactured by Evonik Industries AG (N2SA: 175 m 2 / g, average primary particle size: 17 nm) (iii) Silane coupling agent: NXT manufactured by Momentive (3-octanoylthiopropyltriethoxysilane) (iv) Oil: Process Oil A / OMIX manufactured by Sankyo Yuka Kogyo Co., Ltd. (v) Resin: YS Resin PX850 manufactured by Yasuhara Chemical Co., Ltd. (Softening point 85°C, β-pinene resin (terpene resin)) (vi) Wax: Oz Ace 0355 manufactured by Nippon Seiro Co., Ltd. (vii) Antioxidant-1: No Crack 6C manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine) (Chi) Antioxidant - 2: ANTAGE RD manufactured by Kawaguchi Chemical Industry Co., Ltd. (Poly(2,2,4-trimethyl-1,2-dihydroquinoline) (Ri) Antioxidant - 3: Sirantech S-TMQ manufactured by Sennics (Poly(2,2,4-trimethyl-1,2-dihydroquinoline) (Nu) Processing Aid - 1: Noceller CZ manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (N-Cyclohexylbenzothiazole-2-sulfenamide) (Ru) Processing Aid - 2: Noceller D manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (1,3-Diphenylguanidine (DPG)) (Wo) Processing Aid - 3: Noceller M-P manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. (2-Mercaptobenzothiazole) (Wa) Stearic Acid: Bead Stearic Acid "Tsubaki" manufactured by NOF Corporation (Ka) Zinc Oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. (Yo) Sulfur: Powder sulfur manufactured by Karuizawa Sulfur Co., Ltd. (Ta) Accelerator - 1: Sunseller CM-G manufactured by Sanshin Chemical Industry Co., Ltd. (N-Cyclohexyl-2-benzothiazolylsulfenamide (CBS) (Re) Accelerator - 2: Soxinol DG manufactured by Sumitomo Chemical Co., Ltd. (1,3-Diphenylguanidine (DPG) (So) Accelerator - 3: SUNSINE MBT manufactured by Shandong Shangshun Chemical Industry Co., Ltd. (2-Mercaptobenzothiazole)

[0191] (2) Preparation of Rubber Composition for Tire Tread Based on each formulation 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 accelerator are kneaded at 150°C for 5 minutes to obtain a kneaded product.

[0192] Next, sulfur and a vulcanization accelerator are added to the kneaded material, and it is kneaded for 5 minutes at 80°C using an open roll to obtain the tread rubber compositions of Formulations A to C.

[0193] 2. Molding of Tire Members (Tread, Band, Belt, Carcass) (1) Molding of Tread Next, the tread is molded into a predetermined shape using the rubber composition obtained above.

[0194] (2) Molding of Band In parallel, each band code shown in Tables 2 and 3 is topped with a predetermined rubber composition for the band to mold each band.

[0195] (3) Molding of Belt Similarly, each belt code shown in Tables 2 and 3 is topped with a predetermined rubber composition for the belt to mold each belt.

[0196] (4) Molding of Carcass Similarly, each carcass code shown in Tables 2 and 3 is topped with a predetermined rubber composition for the carcass to mold each carcass.

[0197] 3. Manufacture of Tire Next, each of the obtained tread, band, belt, and carcass is bonded together with other tire members to form an unvulcanized tire, which is press-vulcanized at 170°C for 10 minutes to manufacture the test tires of Examples 1 to 9 and Comparative Examples 1 to 3.

[0198] 4. Performance Evaluation Test (1) Evaluation of Low Fuel Consumption Using a rolling resistance tester, the rolling resistance coefficient (RRC: Rolling Resistance Coefficient) is measured when each test tire runs on a drum at a speed of 80 km / h under the following conditions. Service Rim: 15×6J Internal Pressure: 210 kPa Load: 4.35 kN

[0199] Next, taking the result in Comparative Example 3 as 100, it is exponentiated based on the following formula for low fuel consumption evaluation. The larger the numerical value, the better the low fuel consumption performance is indicated. Rolling resistance evaluation =[(Result of Comparative Example 3) / (Result of the test tire)]×100

[0200] (2) High-speed durability evaluation Each test tire was incorporated into a rim (size = 16×6.0J), the tire was filled with air, and after adjusting the internal pressure to 280 kPa, it was mounted on a drum running tester, a vertical load of 4.22 kN was applied, and the speed was gradually increased from 200 km / h in steps of 10 km / h, and the time and speed until the tire was damaged were measured. The obtained time was divided by the time taken to increase to the next speed, and the value obtained by multiplying by 10 km / h was added to the obtained speed to obtain a combined value.

[0201] Next, taking the result in Comparative Example 3 as 100, it is exponentiated based on the following formula as an index of high-speed durability for evaluation. The larger the numerical value, the better the high-speed durability is indicated. High-speed durability evaluation = [(Result of the test tire) / (Result of Comparative Example 3)]×100

[0202] (3) Comprehensive evaluation Then, (1) and (2) are added together for comprehensive evaluation.

[0203]

Table 1

[0204]

Table 2

[0205]

Table 3

[0206] Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

[0207] The present invention (1) is a carcass including a carcass cord, a belt including a belt cord and provided on the outer side in the tire radial direction of the carcass, a band including a band cord and provided on the outer side in the tire radial direction of the belt, and a tread provided on the outer side in the tire radial direction of the band, and is a tire characterized in that the band cord contains polyethylene terephthalate fiber, 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, and the product (tire weight × diameter of the band cord) of the tire weight (kg) and the diameter (mm) of the band cord is less than 4.3.

[0208] The present invention (2) is characterized in that the ratio (tire weight / maximum load capacity) is less than 0.013, and is the tire according to the present invention (1).

[0209] The present invention (3) is characterized in that the ratio (tire weight / maximum load capacity) is less than 0.012, and is the tire according to the present invention (2).

[0210] The present invention (4) is characterized in that the ratio (tire weight / maximum load capacity) is less than 0.011, and is the tire according to the present invention (3).

[0211] The present invention (5) is characterized in that the ratio (tire weight / maximum load capacity) is less than 0.010, and is the tire according to the present invention (4).

[0212] The present invention (6) is characterized in that the number of filaments of the belt cord is 1 or more and 4 or less, and it is a tire according to the present invention (1).

[0213] The present invention (7) 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, and it is a tire according to the present invention (1).

[0214] The present invention (8) is characterized in that when the tire is viewed from the outside in the tire radial direction in plan view, the crossing angle of the belt cord with respect to the equatorial plane of the tire is less than 25 degrees, and it is a tire according to the present invention (1).

[0215] The present invention (9) is characterized in that the band cord is made by twisting one yarn (single twist), and it is a tire according to the present invention (1).

[0216] The present invention (10) is characterized in that the total fineness of the carcass cord is more than 2400 dtex, and it is a tire according to the present invention (1).

[0217] The present invention (11) 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, and it is a tire according to the present invention (1).

[0218] The present invention (12) is characterized in that the acetone extract (AE amount) of the rubber composition forming the tread is more than 15% by mass, and it is a tire according to the present invention (1).

[0219] The present invention (13) is The polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber, and the tire is the tire according to the present invention (1).

[0220] The present invention (14) is The rubber composition forming the tread contains vegetable oil, and the tire is the tire according to the present invention (1).

[0221] The present invention (15) is The rubber composition forming the tread contains sustainable carbon black, and the tire is the tire according to the present invention (1).

[0222] The present invention (16) is The rubber composition forming the tread contains sustainable silica, and the tire is the tire according to the present invention (1).

Explanation of reference numerals

[0223] 1 Tire 2 Tread 3 Sidewall 4 Chafer 5 Bead 6 Inner liner 7 Carcass 8 Belt 9 Filler 10 Band CL Equatorial plane of the tire

Claims

1. A carcass having a carcass cord; A belt having a belt cord and provided on the outer side in the tire radial direction of the carcass; A band having a band cord and provided on the outer side in the tire radial direction of the belt; A tire comprising a tread provided on the outer side in the tire radial direction of the band, wherein the band cord contains polyethylene terephthalate fiber; 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; a tire characterized in that the product (tire weight × diameter of the band cord) of the tire weight (kg) and the diameter (mm) of the band cord is less than 4.

3.

2. The tire according to claim 1, wherein the ratio (tire weight / maximum load capacity) is less than 0.

013.

3. The tire according to claim 2, wherein the ratio (tire weight / maximum load capacity) is less than 0.

012.

4. The tire according to claim 3, wherein the ratio (tire weight / maximum load capacity) is less than 0.

011.

5. The tire according to claim 4, wherein the ratio (tire weight / maximum load capacity) is less than 0.

010.

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

7. The tire according to claim 1, wherein 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.

8. The tire according to claim 1, wherein when the tire is viewed in plan from the outer side in the tire radial direction, the crossing angle of the belt cord with respect to the equatorial plane of the tire is less than 25 degrees.

9. The tire according to claim 1, wherein the band cord is a single yarn twisted (single twist).

10. The tire according to claim 1, wherein the total fineness of the carcass cord is more than 2400 dtex.

11. The tire according to claim 1, wherein 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.

12. The tire according to claim 1, wherein the acetone extract (AE amount) of the rubber composition forming the tread is more than 15% by mass.

13. The tire according to claim 1, wherein 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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