Tire

Abstract

To improve total performance of high mileage, high speed durability, and steering stability.SOLUTION: This tire comprises: a carcass including a carcass code; a belt including a belt code and provided outside the carcass in a tire radial direction; a band including a band code and provided outside the belt in the tire radial direction; and a tread provided outside the band in the tire radial direction. The band code contains a polyethylene terephthalate fiber. When the tread is seen in the tire radial direction in a plan view, an intersection angle which is smaller one of angles between a tire circumferential direction and the longitudinal direction of the belt code is 0-25 degrees. The belt code includes four or more filaments. A radio (Dba / Dbr) of a band code diameter Dba (mm) to a belt code diameter Dbr (mm) satisfies the following expression: 0.5<Dba / Dbr<1.8 (Expression 1).SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] As in Patent Document 1, in passenger car tires, a band (also called a cap ply) is generally provided between the tread and the belt in order to prevent deformation of the tire due to centrifugal force when traveling at high speeds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-38812 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to improve the overall performance of fuel economy, high-speed durability, and handling stability. [Means for solving the problem]

[0005] The present invention provides a carcass having a carcass cord; a belt including a belt cord and provided on the outer side of the carcass in the tire radial direction; a band provided on the outer side of the belt in the tire radial direction, the band having a band cord; A tire comprising a tread provided on the outer side of the band in the tire radial direction, The band cord contains polyethylene terephthalate fibers, When the tread is viewed in a plane in the tire radial direction, an intersection angle, which is the smaller angle between the tire circumferential direction and the longitudinal direction of the belt cord, is greater than 0 degrees and less than 25 degrees, The belt cord is composed of one or more and four or fewer filaments, a tire characterized in that the ratio (Dba / Dbr) of the band cord diameter Dba (mm) to the belt cord diameter Dbr (mm) satisfies the following formula (1). 0.5 < Dba / Dbr < 1.8 (1 formula)

Effect of the Invention

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

Brief Description of the Drawings

[0007] [Figure 1] It is a schematic cross-sectional view for explaining a tire according to an embodiment of the present invention.

Mode for Carrying Out the Invention

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

[0009] 1. Overview The tire according to the present disclosure includes a carcass provided with a carcass cord, a belt provided with a belt cord on the outer side in the tire radius direction of the carcass, a band provided with a band cord on the outer side in the tire radius direction of the belt, and a tread provided on the outer side in the tire radius direction of the band. And the band cord contains polyethylene terephthalate fiber (PET fiber). Further, the belt cord is composed of one or more and four or fewer filaments, and among the angles formed by the tire circumferential direction and the longitudinal direction of the belt cord when the tread is viewed in a plan view in the tire diameter direction, the smaller intersection angle is more than 0 degrees and less than 25 degrees. Furthermore, the ratio (Dba / Dbr) of the band cord diameter Dba (mm) to the belt cord diameter Dbr (mm) satisfies the formula (1). 0.5 < Dba / Dbr < 1.8 (1 formula)

[0010] These characteristics make it possible to improve overall performance in terms of fuel economy, high-speed durability, and handling stability, as will be described later.

[0011] In this specification, the term "cord diameter" refers to the diameter when the circumscribing circle of a cross section perpendicular to the direction in which the cord extends is a perfect circle, and refers to the diameter equivalent to a perfect circle (the diameter of a perfect circle with the same cross-sectional area) when the circumscribing circle is an ellipse or the like.

[0012] The band cord diameter (Dba) is a value measured in accordance with the test method specified in JIS L1017:2002 "Test methods for synthetic fiber tire cords," and the belt cord diameter (Dbr) is a value measured in accordance with the test method specified in JIS G3510:1992 "Test methods for steel tire cords."

[0013] 2. Mechanism of effect manifestation in tires according to the present disclosure The mechanism by which the above-described effects of the tire according to the present disclosure are exhibited is believed to be as follows.

[0014] (1) Band cord In the tire according to the present invention, a cord containing PET fibers (PET cord) is used for the band cord.

[0015] PET fiber has higher rigidity than nylon 66 (a polyamide synthetic fiber), which has traditionally been used primarily for band cords, so by using PET cord for band cords, it is possible to achieve the same binding force even with a smaller cord diameter (reduced cord gauge). As a result, it is possible to reduce the thickness of the band (prep gauge) and the weight of the band (prep weight), which is thought to lead to a lighter tire, reduced rolling resistance, and improved fuel efficiency.

[0016] In the above, the term "cord containing PET fibers" means that the cord may be made of PET fibers alone, or may be made of a combination of PET fibers and other fibers (polyester fibers other than PET fibers, such as polyethylene naphthalate fibers, aramid fibers, etc.).

[0017] In the present invention, the PET fiber is preferably an environmentally friendly, sustainable material. Examples of sustainable PET fiber (sustainable PET fiber) include recycled PET fiber (recycled PET fiber) made from collected plastic waste such as used PET bottles, old products, and waste materials, and PET fiber (bio-PET fiber) made from biomass.

[0018] A band with a PET cord can be produced by treating the PET cord with an adhesive and then bonding it to a predetermined rubber composition for the band. Examples of adhesives that can be used to bond the PET cord include epoxy compounds such as EX-313 (glycerin polyglycidyl ether, manufactured by Nagase ChemteX Corporation) and RFL (resorcinol-formalin-latex).

[0019] The band cord diameter (Dba) is preferably greater than 0.2 mm, more preferably greater than 0.4 mm, and preferably less than 0.8 mm, more preferably less than 0.6 mm.

[0020] The band may be one layer or two layers, and may be formed across the entire width of the tread, or may be formed only on both ends of the tread.

[0021] (2) Belt cord Tires using PET cords with reduced cord diameters for band cords have poor compression fatigue resistance, which may reduce high-speed durability and handling stability. In addition, because PET cords have high rigidity and a high modulus, the contact shape tends to become rounded, which causes contact pressure to concentrate on the shoulder area, which can become the starting point of failure, and may reduce high-speed durability and handling stability.

[0022] Therefore, in the present invention, the smaller of the angles formed between the tire circumferential direction and the longitudinal direction of the belt cord when the tread is viewed in a plane in the tire radial direction is defined as the "intersection angle," and the "intersection angle," which is theoretically 0 to 90 degrees, is set to be smaller, more than 0 degrees and less than 25 degrees. Less than 24 degrees is more preferable, less than 23 degrees is even more preferable, and less than 22 degrees is even more preferable.

[0023] By reducing the crossing angle in this way, it is possible to increase the tread rigidity and the restraining force, which is thought to improve responsiveness during driving and improve steering stability.

[0024] Furthermore, by reducing the crossing angle, the ground contact shape can be flattened, which negates the disadvantage that the ground contact shape of a band cord using PET cords tends to be rounded as described above, and it is thought that the increased binding force resulting from the use of PET cords and the increased binding force resulting from the reduced crossing angle can improve high-speed durability.

[0025] In the present invention, the crossing angle is expressed as an absolute value without a ± sign, in accordance with the above definition, even when the inclination direction of the belt cords is opposite to the tire circumferential direction. Also, for example, when there are two or more belt layers with different crossing angles, it is sufficient that the crossing angle of at least one belt layer is greater than 0 degrees and less than 25 degrees.

[0026] In the present invention, the belt cord is composed of 1 to 4 filaments. By reducing the number of filaments in this way, it is possible to reduce the weight of the tire and the rolling resistance, which is thought to improve fuel economy.

[0027] The material of the filaments constituting the belt cord is not particularly limited, but is preferably metal, more preferably iron, and particularly preferably steel. The belt cord preferably has a non-twisted 1x1 structure, a single-twisted 1x2 structure, a 1x3 structure, a 1x4 structure, or a layer-twisted 2+2 structure.

[0028] (3) Ratio of band cord diameter Dba to belt cord diameter Dbr (Dba / Dbr) The present inventors conducted further studies and found that when (Dba / Dbr) is appropriately controlled to be greater than 0.5 and less than 1.8, the above-mentioned effects are exerted in cooperation, and the overall performance of fuel economy, high-speed durability, and handling stability can be improved. The lower limit of (Dba / Dbr) is preferably greater than 0.7, more preferably greater than 0.9, and even more preferably greater than 1.1. On the other hand, the upper limit is preferably less than 1.7, more preferably less than 1.6, and even more preferably less than 1.5.

[0029] [2] More preferred embodiments of the tire according to the present disclosure The tire according to the present disclosure can achieve even greater effects by adopting the following aspects.

[0030] 1. The inclusion of isoprene-based rubber in the rubber composition that forms the tread In the present invention, the rubber composition forming the tread (rubber composition for tread) preferably contains more than 25 parts by mass of isoprene-based rubber per 100 parts by mass of the rubber component.

[0031] By including more than 25 parts by mass of isoprene-based rubber per 100 parts by mass of the rubber component, a low heat buildup tread can be achieved that can reduce heat generation during high-speed driving, thereby reducing rolling resistance and further improving fuel economy. Furthermore, it is believed that a decrease in the rigidity (modulus) of the PET cords that occurs as the tread temperature rises can be suppressed, thereby improving high-speed durability. It is more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more. The upper limit is, for example, preferably 70 parts by mass or less, and more preferably 60 parts by mass or less.

[0032] Specific examples of isoprene-based rubber include natural rubber (NR), modified natural rubber (modified NR), modified natural rubber (modified NR), synthetic polyisoprene (isoprene rubber (IR)), and modified isoprene rubber (modified IR). Of these, NR is preferred because of its excellent strength. NR may be, for example, SVR-L, SIR20, RSS#3, or TSR20, which are commonly used in the tire industry.

[0033] 2. Silica content In the present invention, the rubber composition for a tread preferably contains more than 60 parts by mass of silica as a filler per 100 parts by mass of the rubber component. More than 70 parts by mass is more preferable, and more than 80 parts by mass is even more preferable. The upper limit is, for example, preferably less than 150 parts by mass, more preferably less than 130 parts by mass, and even more preferably less than 110 parts by mass.

[0034] Because silica has OH groups on its surface, adding a large amount (more than 60 parts by mass per 100 parts by mass of rubber component) creates hydrogen bonds on the silica surface and interacts with the rubber component. This makes it easier to generate and transmit force within the rubber during driving, and facilitates the transmission of force generated during cornering, which is thought to further improve handling stability.

[0035] Furthermore, it is believed that the OH groups on the surface can capture ozone, improving ozone resistance and further improving high-speed durability.

[0036] 3. Acetone extractables (AE amount) in tread rubber composition Furthermore, in the present invention, the AE amount of the rubber composition for tread is preferably more than 10% by mass, more preferably more than 15% by mass, and even more preferably more than 20% by mass, while the upper limit is, for example, preferably less than 35% by mass, more preferably less than 30% by mass, and particularly preferably 25% by mass or less.

[0037] The AE amount can be considered an index showing the amount of a material that imparts plasticity to the rubber component, such as a softener (plasticizer), in a rubber composition, and can also be considered an index showing the softness of the rubber composition. Therefore, when the AE amount of a rubber composition for a tread is increased to a certain extent, such as more than 10% by mass, the tread blocks can deform flexibly, ensuring a sufficient contact area with the road surface even during high-speed driving and suppressing heat generation due to concentration of contact pressure, which is thought to further improve high-speed durability.

[0038] The AE amount can be measured in accordance with JIS K 6229: 2015. Specifically, the AE amount (mass%) can be obtained by immersing a vulcanized rubber test piece cut out from the measurement site in acetone for a predetermined time and determining the mass loss rate (%) of the test piece.

[0039] More specifically, each vulcanized rubber test piece is immersed in acetone at room temperature and normal pressure for 72 hours to extract the soluble components, and the mass of each test piece is measured before and after extraction, and the mass can be calculated using the following formula. AE amount (%) = {(mass of rubber test piece before extraction - mass of rubber test piece after extraction)} / (mass of rubber test piece before extraction)}×100

[0040] The amount of AE can be appropriately changed by changing the compounding ratio of the plasticizer in the rubber composition.

[0041] The tread may be formed of only one layer (cap rubber layer) that forms the ground contact surface, or may be composed of two layers with a base rubber layer provided inside the cap rubber layer, or may be composed of three layers, or may be four or more layers. In this case, the rubber composition for the tread is the rubber composition that forms the cap rubber layer that is the outermost layer on the ground contact surface side, and preferably satisfies each of the above parameters.

[0042] In this case, the thickness of the cap rubber layer in the entire tread is preferably 10% or more, more preferably 30% or more, even more preferably 50% or more, and even more preferably 70% or more.

[0043] Here, the tread thickness refers to the thickness of the tread on the tire equatorial plane in a radial cross section of the tire. When the tread is formed from a single rubber composition, it refers to the thickness of that rubber composition. When the tread is formed from a laminated structure of multiple rubber compositions, it refers to the thickness of the cap rubber layer, which is the outermost layer on the contact surface side of those layers. It can be measured by aligning the bead portion with the normal rim width in a cross section cut out in the radial direction of the tire.

[0044] "Genuine rim" refers to the rim specified for each tire in the standard system that includes the standard on which the tire is based. For example, for JATMA (Japan Automobile Tire Manufacturers Association), it refers to the standard rim for the applicable size listed in the "JATMA Year Book." For ETRTO (The European Tire and Rim Technical Organization), it refers to the "Measuring Rim" listed in the "Standards Manual." For TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "Year Book." JATMA, ETRTO, and TRA are referenced in that order, and if an applicable size is available at the time of reference, that standard is followed. For tires not specified in the standard, it refers to the rim that can be mounted on the rim and can maintain internal pressure, i.e., the rim with the smallest rim diameter and the next narrowest rim width, among rims that do not leak air between the rim and tire.

[0045] [3] Implementation form Hereinafter, the present disclosure will be specifically described based on embodiments.

[0046] 1. Tire according to this embodiment Fig. 1 is a schematic cross-sectional view illustrating a 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 paper surface is the circumferential direction of the tire. In Fig. 1, the dashed-dotted line CL represents the equatorial plane of the tire. Note that the shape of this tire is symmetrical with respect to the equatorial plane except for the tread pattern, and therefore Fig. 1 shows one-quarter of the entire tire.

[0047] As shown in Fig. 1, the tire 1 includes a tread 2, a pair of sidewalls 3, a pair of chafers 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, with the carcass 7, the belt 8, the band 10, and the tread 2 being arranged from the inside to the outside in the tire radial direction. In Fig. 1, the tread 2 is configured as a single layer.

[0048] With this configuration, as described above, it is believed that by using PET cords as band cords, setting the crossing angle of the belt formed using belt cords having 1 to 4 filaments to less than 25 degrees, and appropriately controlling (Dba / Dbr), it is possible to improve the overall performance of fuel economy, high-speed durability, and handling stability.

[0049] 2. Rubber composition for tread In this embodiment, the rubber composition for tread can be obtained by kneading various compounding materials such as a rubber component, a filler (reinforcing material), a softener component (oil, resin component, etc.), and an antioxidant.

[0050] (1) Compounding materials (a) Rubber component As described above, the rubber component preferably contains an isoprene-based rubber such as natural rubber (NR), but an isoprene-based rubber may be used in combination with a diene-based rubber other than isoprene-based rubber. As the diene-based rubber other than isoprene-based rubber, for example, a diene-based rubber such as styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), or butyl rubber (IIR) may also be used in combination, and two types (NR and SBR or NR and BR) or three types (NR, SBR, and BR) may be used in combination.

[0051] (a) Isoprene rubber As described above, the isoprene-based rubber may be natural rubber (NR), or an isoprene-based rubber other than NR (modified natural rubber (modified NR), modified natural rubber (modified NR), or synthetic polyisoprene rubber such as synthetic polyisoprene (isoprene rubber (IR), modified isoprene rubber (modified IR)). The content of the isoprene-based rubber in 100 parts by mass of the rubber component is as described above.

[0052] As the NR, for example, SVR-L, SIR20, RSS#3, TSR20, and the like, which are commonly used in the tire industry, can be used.

[0053] Examples of isoprene-based rubbers other than NR include isoprene rubber (IR), modified NR, modified NR, and modified IR. The IR is not particularly limited, and for example, IR2200 manufactured by Zeon Corporation and other commonly used rubbers in the tire industry can be used. Examples of modified NR include deproteinized natural rubber (DPNR) and highly purified natural rubber (UPNR). Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0054] (b) 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 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 more than 5% by mass, more preferably more than 10% by mass, and even more preferably more than 15% by mass. On the other hand, it is preferably less than 70% by mass, more preferably less than 40% by mass, and even more preferably less than 30% by mass. The structural identification of SBR (measurement of styrene content and vinyl content) can be performed using, for example, a JNM-ECA series instrument manufactured by JEOL Ltd.

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

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

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

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

[0059] [ka]

[0060] In the formula, R 1 , R 2 and R 3 R may be the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group.4 and R 5 may bond to form a ring structure together with the nitrogen atom, and n represents an integer.

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

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

[0063] Specific examples of the modifying agent include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. These may be used alone or in combination of two or more.

[0064] Modified SBR may also be modified with the following compounds (modifiers): Examples of the modifier include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups, such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline; Diglycidyl amino compounds such as diglycidyl orthotoluidine, tetraglycidyl meta-xylenediamine, tetraglycidyl aminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidyl aminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, and N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(trippropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxy sulfide group-containing silane compounds such as (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, Alkoxysilanes such as thyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, and N,N,N',N'-bis-(tetraethylamino)benzophenone; 4-N,N- Benzaldehyde compounds having an amino group and / or a substituted amino group, such as dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, and 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, and N-methyl-5-methyl-2-pyrrolidone; and N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurylolactam, N-vinyl-ω-laurylolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam; as well as N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), and tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione , N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophen, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. Modification with the above compounds (modifiers) can be carried out by known methods.

[0065] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., ENEOS Material Corporation, Asahi Kasei Corporation, Zeon Corporation, etc. can be used. The SBR may be used alone or in combination of two or more types.

[0066] The amount of SBR in 100 parts by mass of the rubber component is preferably 10 parts by mass or more, more preferably 25 parts by mass or more, and even more preferably 40 parts by mass or more, and the upper limit is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less.

[0067] (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 not more than 98% by mass. 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.

[0068] The BR is not particularly limited, and can be a BR with a high cis content (cis content of 90% or more), a BR with a low cis content, a BR containing syndiotactic polybutadiene crystals, etc. The BR can be either unmodified or modified, and the modified BR can be, for example, BR modified with a compound (modifier) ​​represented by the following formula:

[0069] [ka]

[0070] In the formula, R 1 , R 2 and R 3 R may be the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. 4 and R 5 may bond to form a ring structure together with the nitrogen atom, and n represents an integer.

[0071] The modified BR modified with the compound (modifying agent) represented by the above formula includes BR whose polymerization terminal (active terminal) has been modified with the compound represented by the above formula.

[0072] R 1 , R 2 and R 3 R is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). 4 and R 5 is preferably an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and even more preferably 3. In addition, R 4 and R 5When the groups bond to form a ring structure together with the nitrogen atom, the ring is preferably a 4- to 8-membered ring. The alkoxy group also includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group or a benzyloxy group).

[0073] Specific examples of the modifying agent include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. These may be used alone or in combination of two or more.

[0074] The modified BR may also be modified with the following compounds (modifiers): Examples of the modifier include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline; Diglycidyl amino compounds such as diglycidyl orthotoluidine, tetraglycidyl meta-xylenediamine, tetraglycidyl aminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidyl aminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, and N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(trippropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxy sulfide group-containing silane compounds such as (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, Alkoxysilanes such as thyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, and N,N,N',N'-bis-(tetraethylamino)benzophenone; 4-N,N- Benzaldehyde compounds having an amino group and / or a substituted amino group, such as dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, and 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones, such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, and N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones, such as N-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurylolactam, N-vinyl-ω-laurylolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam; as well as N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), and tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione , N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophen, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. Modification with the above compounds (modifiers) can be carried out by known methods. These modified BRs may be used alone or in combination of two or more.

[0075] As the BR, for example, products from Ube Industries, Ltd., ENEOS Materials Corporation, Asahi Kasei Corporation, Zeon Corporation, etc. can be used.

[0076] The amount of BR in 100 parts by mass of the rubber component is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less.

[0077] (d) Other rubber components The rubber composition may contain, as other rubber components, rubbers (polymers) that are generally used in the production of tires, such as nitrile rubber (NBR), as needed.

[0078] The raw materials (monomers) of the above-mentioned synthetic rubbers such as IR, SBR, and BR may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0079] Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples thereof include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyls include, but are not particularly limited to, styrene. Among these, it is preferable to use recycled polyisoprene (recycled isoprene), butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) as raw materials.

[0080] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0081] 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. Biomass is not particularly limited, but examples include agricultural, forestry, and fishery products, sugar, wood chips, plant residues after useful components have been obtained, plant-derived ethanol, and biomass naphtha.

[0082] Monomers derived from biomass (biomass monomers) are not particularly limited and include biomass-derived butadiene and biomass-derived aromatic vinyl. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyls include, but are not particularly limited to, styrene. The method for producing biomass monomers is not particularly limited and includes, for example, biological and / or chemical and / or physical conversion of animals and plants. A representative example of biological conversion is fermentation by microorganisms, and examples of chemical and / or physical conversion include catalytic conversion, high heat conversion, high pressure conversion, electromagnetic wave conversion, critical fluid conversion, and combinations thereof.

[0083] The polymer synthesized from a biomass monomer component (biomass polymer) is not particularly limited, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0084] Whether the raw material of a polymer is derived from biomass can be determined by the pMC (percent modern carbon) measured in accordance with ASTM D6866-10.

[0085] pMC is the modern standard reference carbon 14 of sample against C concentration 14 This is the ratio of C concentrations and is a value used as an index of the biomass ratio of a compound. The significance of this value is explained below.

[0086] 1 mole of carbon atoms (6.02 × 10 23 ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. 11 pieces 14C exists. 14 C is called a radioactive isotope, and its half-life is 5,730 years, and it decreases regularly. It takes 226,000 years for all of it to decay. Therefore, in fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when it was first fixed. 14 All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain 14 Therefore, chemicals produced from these fossil fuels do not contain any C element. 14 It does not contain any C elements.

[0087] on the other hand, 14 C is produced continuously by nuclear reactions in the atmosphere caused by cosmic rays, and in the Earth's atmospheric environment, the amount of C is balanced by the decrease caused by radioactive decay. 14 Therefore, the amount of carbon derived from biomass resources currently circulating in the environment is constant. 14 As mentioned above, the C concentration is approximately 1 × 10 -12 The value is approximately mol %. Therefore, the biomass ratio in a compound can be calculated by using the difference between these values.

[0088] this 14 C is typically measured using accelerator mass spectrometry based on a tandem accelerator. 13 C concentration ( 13 C / 12 C). 14 C concentration ( 14 C / 12 C) is measured. 14 The modern standard reference for the C concentration is the carbon circulating in nature as of 1950. 14The specific standard substance used is the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific activity of carbon in this oxalic acid (per gram of carbon) is 14 The radioactivity of C is separated into carbon isotopes, 13 The standard value is the value corrected for decay from 1950 to the measurement date. 14 This is used as the C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0089] Therefore, if rubber is made from 100% biomass (natural) derived materials, although there are regional differences, it will usually not reach 100 under normal conditions, so it will show a value of approximately 110pMC. On the other hand, for chemical substances derived from petroleum and other fossil fuels, 14 When the carbon concentration is measured, it will show a range of about 0 pMC (for example, 0.3 pMC), which corresponds to the biomass ratio of 0% mentioned above.

[0090] For these reasons, it is preferable from the standpoint of environmental protection (sustainability) to use a material such as rubber with a high pMC value, that is, a material such as rubber with a high biomass ratio, in a rubber composition.

[0091] (b) Compounding materials other than rubber components (a) Filler The rubber composition preferably contains silica or carbon black as a reinforcing agent, but may also contain other fillers, such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. When silica is used, it is preferably used in combination with a silane coupling agent.

[0092] (i) Silica As described above, silica has OH groups on the surface, and by blending it in an appropriate amount of more than 60 parts by mass per 100 parts by mass of the rubber component, it is possible to improve the handling stability and high-speed durability.

[0093] The BET specific surface area of ​​silica is 100m from the viewpoint of obtaining good durability. 2 / g, and preferably greater than 130m 2 / g. On the other hand, it is more preferable that the 2 / g, and preferably less than 200m 2 / g or less. The BET specific surface area is the N2SA value measured by the BET method in accordance with ASTM D3037-93.

[0094] The silica is not particularly limited, and for example, silica commonly used in the tire industry, such as silica prepared by a dry method (anhydrous silica) or silica prepared by a wet method (hydrated silica), can be used. Commercially available products include those from Evonik Industries, Rhodia, Tosoh Silica Corporation, Solvay Japan, Tokuyama Corporation, etc.

[0095] The raw material for silica is not particularly limited, and may be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from biomass materials such as rice husk), or silica recycled from a product containing silica. Among these, hydrated silica prepared by a wet method is preferred because it contains a large number of silanol groups. However, sustainable silica (silica made from biomass materials or silica recycled from a product containing silica) is preferred.

[0096] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet-process silica to produce a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0097] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0098] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, it is possible to suppress the crystallization of silica in rice husk ash (see, for example, JP 2009-2594 A and Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222).

[0099] Amorphous silica extracted from rice husks may be commercially available from Wilmar Co., Ltd., etc.

[0100] These silicas may be used alone or in combination of two or more. The use of biomass silica or recycled silica is preferable from the viewpoint of environmental protection (sustainability).

[0101] Since a too small particle size (average primary particle size) of silica leads to poor processability, it is preferably greater than 8 nm, more preferably greater than 9 nm, and even more preferably greater than 10 nm, while from the viewpoint of ensuring rubber reinforcement, it is preferably less than 25 nm, more preferably less than 20 nm, and even more preferably less than 17 nm.

[0102] The average primary particle size of silica refers to the average value of the diameter of the circle measured by observing the smallest particle unit of silica constituting the aggregate structure as a circle and measuring the absolute maximum length of the smallest particle. The average primary particle size of silica can be determined by observing with a transmission or scanning electron microscope, measuring 400 or more primary particles of silica observed within the field of view, and averaging the measured values.

[0103] Specifically, silica particles extracted from a rubber composition cut out from a tire are directly observed using an electron microscope or the like, and the equivalent cross-sectional area diameter is calculated from the area of ​​each silica particle obtained, and the average value is calculated, thereby allowing the average primary particle diameter to be calculated.

[0104] (ii) Silane coupling agent When silica is used, it is preferable to use a silane coupling agent in combination in order to enhance the dispersibility of the silica and also to improve the mechanical properties and moldability by reacting with the silica.

[0105] The silane coupling agent is not particularly limited, and examples thereof include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, and bis(4-trimethoxysilylbutyl). Trisulfide, 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-triethoxysilyl Examples of suitable silane coupling agents include sulfide-based silanes such as silylethyl-N,N-dimethylthiocarbamoyl tetrasulfide and 3-triethoxysilylpropyl methacrylate monosulfide, mercapto-based silanes such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z, vinyl-based silanes such as vinyltriethoxysilane and vinyltrimethoxysilane, amino-based silanes such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane, glycidoxy-based silanes such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, nitro-based silanes such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, and chloro-based silanes such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Among these, silane coupling agents having a thiocarbonyl group, such as the above-mentioned NXT, are preferred. These silane coupling agents may be used alone or in combination of two or more.

[0106] As the silane coupling agent, for example, products from Evonik Industries, Momentive, Shin-Etsu Silicones Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Dow Corning Toray Co., Ltd., etc. can be used.

[0107] The content of the silane coupling agent is, for example, preferably more than 3 parts by mass, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, relative to 100 parts by mass of silica. The upper limit is, for example, preferably less than 15 parts by mass, more preferably 12 parts by mass or less, and even more preferably 9 parts by mass or less.

[0108] (iii) Carbon black Carbon black is preferably used for the purpose of improving the crack growth resistance, durability, resistance to ultraviolet degradation, etc. of the tire.

[0109] The nitrogen adsorption specific surface area (N2SA) of carbon black is 30m from the viewpoint of reinforcing properties for rubber. 2 / g or more, and 2 / g or more is more preferable, and 60m 2 On the other hand, from the viewpoint of heat buildup, it is more preferable that the solubility is 250m / g or more. 2 / g or less, and 150m 2 / g or less is more preferable, and 120m 2 The nitrogen adsorption specific surface area of ​​carbon black is measured in accordance with ASTM D4820-93.

[0110] From the viewpoint of rubber rigidity, the dibutyl phthalate (DBP) absorption of carbon black is preferably 50 ml / 100 g or more, more preferably 100 ml / 100 g or more. On the other hand, from the viewpoint of rubber deformation compliance, it is preferably 250 ml / 100 g or less, more preferably 150 ml / 100 g or less. The DBP absorption of carbon black is measured according to ASTM D2414-93.

[0111] The carbon black is not particularly limited, and examples thereof include furnace blacks (furnace carbon black) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal blacks (thermal carbon black) such as FT and MT; and channel blacks (channel carbon black) such as EPC, MPC, and CC, and examples of product numbers include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These may be used alone or in combination of two or more.

[0112] In addition to mineral oil, the raw material for carbon black may be biomass materials such as lignin and vegetable oil, or pyrolysis oil obtained by pyrolyzing rubber products such as waste tires (recycled carbon black). The use of these sustainable carbon blacks is preferable from the viewpoint of environmental protection.

[0113] The carbon black may be produced by combustion such as a furnace method, by hydrothermal carbonization (HTC), or by thermal decomposition of methane such as a thermal black method.

[0114] Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., Columbia Carbon Co., Ltd., etc. These may be used alone or in combination of two or more. The carbon black content is as described above.

[0115] The amount of carbon black per 100 parts by mass of the rubber component is preferably more than 5 parts by mass, more preferably more than 8 parts by mass, and even more preferably more than 10 parts by mass, and the upper limit is preferably less than 40 parts by mass, and more preferably less than 35 parts by mass.

[0116] (iv) Other fillers In addition to the above-mentioned carbon black and silica, the rubber composition may further contain fillers commonly used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, magnesium sulfate, etc. The content of these fillers is, for example, more than 0.1 part by mass and less than 150 parts by mass per 100 parts by mass of the rubber component.

[0117] (b) Softener component It is preferable to use a softener component in the rubber composition as needed from the viewpoint of imparting plasticity to the rubber component during kneading and properly dispersing the powder material. The softener component here is a concept that includes both softeners that are liquid at 25°C and softeners that are solid at 25°C.

[0118] Examples of softeners include resin components, oils, liquid polymers, and ester-based plasticizers. These softeners may be derived from mineral resources such as petroleum and natural gas, biomass-derived softeners, or naphtha recycled from rubber or non-rubber products. Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as softeners. Among these, biomass-derived and recycled softeners are preferred as sustainable softeners.

[0119] These softeners may be used alone or in combination of two or more. The content of the softener component per 100 parts by mass of the rubber component is preferably more than 5 parts by mass, more preferably more than 10 parts by mass, and even more preferably more than 20 parts by mass. The upper limit is, for example, preferably less than 70 parts by mass, more preferably less than 60 parts by mass, and even more preferably less than 55 parts by mass. The content of the softener component also includes the amount of oil contained in the rubber (oil-extended rubber) etc.

[0120] (i) Oil Examples of oils include mineral oil, vegetable oil, animal oil, etc. From the viewpoint of life cycle assessment, waste oils used in rubber mixers or engines, or refined waste cooking oils used in restaurants may also be used, and among these, vegetable oils are preferred.

[0121] (i-1) Mineral oil In this specification, mineral oil refers to oil derived from mineral resources such as petroleum, natural gas, etc. Examples of mineral oil include paraffinic oil (mineral oil), naphthenic oil, and aromatic oil.

[0122] Specific examples of mineral oils include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract).

[0123] Additionally, to address environmental concerns, oils with low polycyclic aromatic compound (PCA) content can be used, such as MES, TDAE, and heavy naphthenic oils.

[0124] Examples of commercially available mineral oils include paraffinic, aromatic, and naphthenic oils, and usable products include those from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Showa Shell Sekiyu K.K., and Fuji Kosan Co., Ltd. These may be used alone or in combination of two or more.

[0125] (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, grapeseed oil, and wood wax.

[0126] Further examples of vegetable oils include refined oils (salad oil, etc.) obtained by refining the above oils, interesterified oils, hydrogenated hardened oils, thermally polymerized oils, oxidatively polymerized oils, and waste edible oils recovered from those used as edible oils. Vegetable oils may be liquid or solid at room temperature (25°C). These may be used alone or in combination of two or more.

[0127] The vegetable oil preferably contains acylglycerol, and more preferably triacylglycerol. Acylglycerol refers to a compound in which a hydroxyl group of glycerin is ester-bonded to a fatty acid. The acylglycerol is not particularly limited, and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, or a polymer (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. Acylglycerol may be liquid or solid at room temperature (25°C).

[0128] The method for confirming whether or not acylglycerol is contained in the rubber composition is not particularly limited, but may be 1 For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours, and after removing the rubber composition, the 1When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal of tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to the carbon atoms adjacent to the oxygen atoms of the ester groups, and therefore the presence of acylglycerol can be confirmed. Here, "around" refers to a range of ±0.10 ppm.

[0129] The fatty acid is not particularly limited and may be either 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.

[0130] Among these, it is desirable that the fatty acid contains a fatty acid with few double bonds, i.e., a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As a vegetable oil containing such a fatty acid, for example, vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid may be used, or vegetable oil modified by ester exchange or the like may be used. Furthermore, in order to produce vegetable oil containing such a fatty acid, plants may be improved by breeding, genetic modification, genome editing, or the like.

[0131] As the vegetable oil, for example, commercially available products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0132] (ii) Liquid rubber Liquid rubber is a polymer that is in a liquid state at room temperature (25°C) and is a rubber component that can be extracted by acetone extraction from a vulcanized tire. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and hydrogenated products thereof.

[0133] Farnesene polymers are polymers obtained by polymerizing farnesene, which contains structural units 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).

[0134] 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).

[0135] Examples of liquid diene polymers include liquid styrene butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), and liquid styrene isoprene copolymer (liquid SIR).

[0136] The liquid diene polymer has a weight average molecular weight (Mw) of, for example, 1.0 × 10 in terms of polystyrene measured by gel permeation chromatography (GPC). 3 Super, 2.0×10 5 Here, the Mw of the liquid diene polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0137] As the liquid rubber, for example, products of Kuraray Co., Ltd., Cray Valley Co., Ltd., etc. can be used.

[0138] (iii) Resin component The resin component also functions as a tackifier and may be solid or liquid at room temperature. Specific examples of the resin component include rosin resins, styrene resins, coumarone resins, terpene resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins, and two or more of these resins may be used in combination. These resin components may be provided with a modifying group capable of reacting with silica, etc., as needed. The content of the resin component per 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 even more preferably 50 parts by mass or more.

[0139] Rosin-based resins are resins whose main component is rosin acid obtained by processing pine resin. These rosin-based resins (rosins) can be classified based on whether they are modified or not, and can be divided into unmodified rosin (unmodified rosin) and modified rosin (rosin derivatives). Examples of unmodified rosins include tall rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Modified rosin is a modification of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid-modified rosin esters, unsaturated carboxylic acid-modified rosin esters, rosin amide compounds, and rosin amine salts.

[0140] Styrenic resins are polymers that use styrene monomers as constituent monomers, and examples thereof include polymers obtained by polymerizing styrene monomers as the main component (50% by mass or more).Specific examples include 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.) individually, copolymers obtained by copolymerizing two or more styrene monomers, and copolymers of styrene monomers and other monomers that can be copolymerized with them.

[0141] Examples of the other monomers include acrylonitriles such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylics and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene and butadiene isoprene, olefins such as 1-butene and 1-pentene, α,β-unsaturated carboxylic acids or acid anhydrides thereof such as maleic anhydride, and the like.

[0142] Among the coumarone resins, coumarone-indene resins are preferred. Coumarone-indene resins are resins containing coumarone and indene as monomer components constituting the resin skeleton (main chain). Monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, etc.

[0143] The hydroxyl value (OH value) of the coumarone-indene resin is, for example, more than 15 mgKOH / g and less than 150 mgKOH / g. The OH value is the amount of potassium hydroxide, expressed in milligrams, required to neutralize acetic acid bonded to hydroxyl groups when acetylating 1 g of the resin, and is a value measured by potentiometric titration (JIS K 0070:1992).

[0144] The softening point of the coumarone-indene resin is, for example, more than 30° C. and less than 160° C. The softening point is the temperature at which the ball drops when the softening point specified in JIS K 6220-1:2001 is measured using a ring and ball softening point tester.

[0145] Terpene resins include polyterpenes, terpene phenols, and aromatic modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are (C5H8) n The hydrocarbons and their oxygen-containing derivatives are represented by the following composition: monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32), and examples thereof include α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0146] Examples of polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin, which are made from the above-mentioned terpene compounds, as well as hydrogenated terpene resins obtained by hydrogenating the terpene resins. Examples of terpene phenols include resins obtained by copolymerizing the above-mentioned terpene compounds with phenolic compounds, and resins obtained by hydrogenating the above-mentioned resins. Specific examples include resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds, and formalin. Examples of phenolic compounds include phenol, bisphenol A, cresol, and xylenol. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating the above-mentioned resins. The aromatic compound is not particularly limited as long as it is a compound having an aromatic ring, and examples thereof include phenolic compounds such as phenol, alkylphenol, alkoxyphenol, and unsaturated hydrocarbon group-containing phenol; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, and unsaturated hydrocarbon group-containing naphthol; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and unsaturated hydrocarbon group-containing styrene; coumarone, indene, and the like.

[0147] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of C5 fractions include petroleum fractions having 4 to 5 carbon atoms, such as cyclopentadiene, pentene, pentadiene, and isoprene. Dicyclopentadiene resin (DCPD resin) is preferably used as a C5 petroleum resin.

[0148] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, and may be a hydrogenated or modified version. Examples of C9 fractions include petroleum fractions having 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, indene, and methylindene. Specific examples of suitable aromatic vinyl resins include coumarone-indene resins, coumarone resins, indene resins, and aromatic vinyl resins. Preferred aromatic vinyl resins are α-methylstyrene (AMS resin), styrene homopolymers, and copolymers of α-methylstyrene and styrene, with copolymers of α-methylstyrene and styrene being more preferred, due to their economical efficiency, ease of processing, and excellent heat generation. Examples of aromatic vinyl resins that can be used include those commercially available from Kraton, Eastman Chemical, and the like.

[0149] "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, and may be a hydrogenated or modified resin. Examples of C5 fractions and C9 fractions include the petroleum fractions mentioned above. As the C5C9 resin, for example, commercially available products from Tosoh Corporation, LUHUA, etc. can be used.

[0150] The acrylic resin is not particularly limited, but for example, a solventless acrylic resin can be used.

[0151] Examples of solvent-free acrylic resins include (meth)acrylic resins (polymers) synthesized by high-temperature continuous polymerization (high-temperature continuous bulk polymerization) (methods described in U.S. Pat. No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Pat. No. 5,010,166, and Toa Gosei Kenkyusho TREND 2000 Vol. 3, pp. 42-45, etc.), with minimal use of secondary raw materials such as polymerization initiators, chain transfer agents, and organic solvents. In this disclosure, (meth)acrylic refers to both methacrylic and acrylic.

[0152] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0153] In addition, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or a (meth)acrylic acid derivative as a monomer component constituting the acrylic resin.

[0154] The acrylic resin may be a resin composed solely of a (meth)acrylic component, or a resin containing components other than a (meth)acrylic component, and may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0155] As the resin component, for example, products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Clayton, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., Taoka Chemical Co., Ltd., etc. can be used.

[0156] (c) Wax The rubber composition may contain wax. The wax content is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit is, for example, preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 4 parts by mass or less.

[0157] The wax is not particularly limited, and any wax commonly used in the tire industry can be suitably used. Examples include mineral waxes and plant-derived waxes. 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 these, plant-derived waxes are preferred from the viewpoint of sustainable materials.

[0158] Examples of plant-derived waxes include rice wax, carnauba wax, and candelilla wax. Examples of mineral waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. Note that stearic acid is not included in the wax.

[0159] The wax that can be used may be commercially available waxes from, for example, Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Co., Ltd., etc. These waxes may be used alone or in combination of two or more.

[0160] (d) Antiaging agents The rubber composition may contain an antioxidant. The content of the antioxidant is, for example, preferably more than 1 part by mass and the upper limit is preferably less than 10 parts by mass per 100 parts by mass of the rubber component.

[0161] The antioxidant is not particularly limited, but examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; 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), and N,N'-ditolyl-p-phenylenediamine. p-phenylenediamine-based antioxidants such as diisopropyl-N'-phenyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers; monophenol-based antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis-, tris-, and polyphenol-based antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. These may be used alone or in combination of two or more.

[0162] As commercially available products, for example, products from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis, etc. can be used.

[0163] (e) Processing aids The rubber composition may contain a processing aid. Examples of processing aids include metal salts (compounds in which the hydrogen atoms of an acid are substituted with metal ions), fatty acid amides, amide esters, and fatty acid esters. These may be used alone or in combination of two or more. Of these, metal salts and fatty acid amides are preferred, and metal salts are more preferred.

[0164] Examples of metals used in metal salts include alkali metals such as potassium and sodium, and alkaline earth metals such as calcium and barium. Magnesium, zinc, nickel, molybdenum, etc. can also be used. Of these, alkali metals are preferred.

[0165] Examples of acids used in metal salts include fatty acids such as lauric acid, myristic acid, palmitic acid, etc. In addition, boric acid, carbonic acid, hydrochloric acid, nitric acid, sulfuric acid, etc. can also be used.

[0166] As commercially available processing aids, products from Kishida Chemical Co., Ltd., Kenei Pharmaceutical Co., Ltd., Struktol Co., Ltd., Performance Additives Co., Ltd., etc. can be used.

[0167] The content of the processing aid is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, per 100 parts by mass of the rubber component, and the upper limit is, for example, preferably 6 parts by mass or less, and more preferably 4 parts by mass or less.

[0168] (f) Lubricant (stearic acid) The rubber composition may contain a lubricant. A lubricant based on a fatty acid derivative such as stearic acid is preferably used as the lubricant. Conventionally known stearic acids can be used, specifically, products from NOF Corporation, NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc. can be used. Struktol WB16 manufactured by Struktol Co., Ltd. can also be used.

[0169] The content of stearic acid is, for example, preferably more than 0.5 parts by mass and the upper limit is preferably less than 10.0 parts by mass relative to 100 parts by mass of the rubber component.

[0170] (g) Zinc oxide The rubber composition may contain zinc oxide. The content of zinc oxide is, for example, preferably more than 0.5 parts by mass, and the upper limit is preferably less than 10 parts by mass, per 100 parts by mass of the rubber component. As the zinc oxide, a conventionally known product can be used, and for example, products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0171] (H) Crosslinking agents and vulcanization accelerators The rubber composition preferably contains a cross-linking agent such as sulfur. The content of the cross-linking agent is preferably, for example, more than 0.1 parts by mass, and the upper limit is preferably less than 10.0 parts by mass, per 100 parts by mass of the rubber component. The sulfur content is the pure sulfur content, and when insoluble sulfur is used, it is the content excluding oil content.

[0172] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. These may be used alone or in combination of two or more.

[0173] As sulfur, for example, products from Tsurumi Chemical Industry Co., Ltd., Karuizawa Iso Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0174] Crosslinking agents other than sulfur may also be used. Specific examples include vulcanizing agents containing sulfur atoms, such as Tackirol V200 manufactured by Taoka Chemical Co., Ltd., DURALINK HTS (sodium 1,6-hexamethylenedithiosulfate dihydrate) manufactured by Flexis, and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane: hybrid crosslinking agent) manufactured by Lanxess, as well as organic peroxides such as dicumyl peroxide.

[0175] The rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, preferably more than 0.3 parts by mass and the upper limit is preferably less than 10.0 parts by mass per 100 parts by mass of the rubber component.

[0176] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenyl guanidine, di-orthotolyl guanidine, and orthotolyl biguanidine. These may be used alone or in combination of two or more.

[0177] (R) Other In addition to the above-mentioned components, the rubber composition may contain additives commonly used in the tire industry, such as organic fillers such as cellulose fibers, organic peroxides, etc. The content of these additives is, for example, more than 0.1 parts by mass and less than 50 parts by mass per 100 parts by mass of the rubber component.

[0178] In the present disclosure, among the above-mentioned materials, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from carbon dioxide in the atmosphere. As a method for obtaining the compound of the present disclosure from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through a methanation process in which methane is synthesized from carbon dioxide may be converted.

[0179] (2) Preparation of rubber composition The rubber composition can be produced by a general method, for example, a production method including a base kneading step of kneading a rubber component with a filler such as silica, and a finish kneading step of kneading the kneaded product obtained in the base kneading step with a crosslinking agent.

[0180] The kneading can be carried out using a known (internal) kneading machine such as a Banbury mixer, a kneader, or an open roll.

[0181] The kneading temperature in the base kneading step is, for example, preferably above 50° C., with the upper limit preferably being below 200° C. The kneading time is, for example, preferably above 30 seconds, with the upper limit preferably being less than 30 minutes. In the base kneading step, in addition to the above components, compounding agents conventionally used in the rubber industry, for example, softeners such as oil, stearic acid, zinc oxide, antioxidants, waxes, vulcanization accelerators, etc., may be added and kneaded as needed.

[0182] In the final kneading step, the kneaded product obtained in the base kneading step is kneaded with a crosslinking agent. The kneading temperature in the final kneading step is, for example, preferably above room temperature, and the upper limit is preferably less than 80°C. The kneading time is, for example, preferably more than 1 minute and less than 15 minutes. In the final kneading step, in addition to the above components, a vulcanization accelerator, zinc oxide, etc. may be appropriately added and kneaded as necessary.

[0183] The rubber composition obtained as described above can then be extruded into a predetermined shape to form a tread.

[0184] 3. Tire manufacturing The tire according to the present embodiment can be manufactured by a conventional method. First, the rubber composition obtained as described above is molded into a predetermined shape to manufacture a tread. Next, the rubber composition is combined with other rubber components on a tire building machine to manufacture an unvulcanized tire.

[0185] Specifically, an inner liner as a component for ensuring the airtightness of the tire, a carcass as a component for withstanding the load, impact, and inflation pressure to which the tire is subjected, and a belt component, band, etc. as a component for tightly fastening the carcass and increasing the rigidity of the tread are wound around a forming drum, and both ends of the carcass are fixed to both side edges, and bead portions as components for fixing the tire to the rim are arranged. After forming into a toroidal shape, a tread is attached to the center of the outer periphery and sidewalls are attached to the radially outer sides to form side portions, thereby producing an unvulcanized tire.

[0186] The unvulcanized tire produced as described above is then heated and pressurized in a vulcanizer to obtain a tire. The vulcanization step can be carried out by applying a known vulcanization method. The vulcanization temperature is preferably, for example, above 120°C, and the upper limit is preferably below 200°C. The vulcanization time is preferably, for example, above 5 minutes, and the upper limit is preferably below 15 minutes.

[0187] As described above, the tire obtained as described above exhibits the effects of using PET cords as band cords and the effects of reducing the crossing angle of the belt cords, which are composed of a small number of filaments, in cooperation with each other by appropriately controlling (Dba / Dbr), thereby improving the overall performance of fuel economy, high-speed durability, and handling stability.

[0188] The tires according to the present disclosure can be suitably used as passenger car tires, large passenger car tires, large SUV tires, truck and bus tires, motorcycle tires, racing tires, winter tires such as studless tires, all-season tires, run-flat tires, etc., and are particularly preferably used as passenger car tires. [Example]

[0189] Below, examples (embodiments) that are considered preferable for implementation will be shown, but the scope of the present invention is not limited to these examples.

[0190] A tire (tire size: 215 / 60R16) consisting of a tread molded from the various compound materials shown below, as well as tire components such as bands and belts, was examined, and the results calculated based on the evaluation methods described below regarding fuel economy, high-speed durability, and handling stability are also shown at the bottom of Tables 2 and 3.

[0191] 1. Preparation of Rubber Composition A rubber composition for a tread is prepared using the various compounding materials shown below.

[0192] (1) Compounding materials (a) Rubber component (a) SBR: SBR1502 manufactured by ENEOS Materials Co., Ltd. (styrene content: 23.5% by mass) (b) NR:TSR20 (c) BR: BR150B manufactured by Ube Industries (Cis content 96% by mass)

[0193] (b) Compounding materials other than rubber components (a) Carbon black: Show Black N220 manufactured by Cabot Japan (N2SA:111m 2 / g) (b) Silica: Ultrasil VN3 manufactured by Evonik Industries (N2SA:175m 2 / g) (c) Silane coupling agent: Si266 manufactured by Evonik Industries (Bis(3-triethoxysilylpropyl)disulfide) (d) Oil: H&R Vivatec 500 (TDAE, aromatic mineral oil) (e) Resin: SYLVARES SA85 manufactured by Arizona Chemical Company (α-methylstyrene resin: copolymer of α-methylstyrene and styrene, softening point 85°C) (F) Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. (g) Anti-aging agent: Antigen 6C manufactured by Sumitomo Chemical Co., Ltd. (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) (H) Stearic acid: NOF Corp. stearic acid beads "Tsubaki" (i) Zinc oxide: Zinc oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. (J) Sulfur: HK-200-5 (powdered sulfur) manufactured by Hosoi Chemical Industry Co., Ltd. (k) Vulcanization accelerator: Noccela D manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N,N´-diphenylguanidine)

[0194] (2) Preparation of rubber composition for tread Based on each of the blends A to C shown in Table 1, materials other than sulfur and vulcanization accelerator are kneaded for 5 minutes at 150°C using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded mixture.

[0195] Next, sulfur and a vulcanization accelerator are added to the kneaded mixture, and the mixture is kneaded for 5 minutes under the condition of 80°C using an open roll to obtain rubber compositions for treads of formulations A to C.

[0196] 2. Forming of tire components (tread, band, belt) (1) Tread molding Next, the rubber composition obtained above is molded into a tread having a predetermined shape.

[0197] (2) Forming the band In parallel, each band cord shown in Tables 2 and 3 is topped with a predetermined rubber composition for the band to form each band.

[0198] (3) Belt molding Similarly, each belt cord shown in Tables 2 and 3 is topped with a predetermined rubber composition for belts to form each belt.

[0199] 3. Tire manufacturing Next, each of the treads, bands, and belts obtained above is bonded together with other tire components to form an unvulcanized tire, which is then press-vulcanized for 10 minutes under a condition of 170°C to produce test tires for Examples 1 to 5 and Comparative Examples 1 to 6.

[0200] 4. Performance evaluation test (1) Fuel efficiency evaluation Using a rolling resistance tester, measure the rolling resistance coefficient (RRC) when each test tire runs on a drum at a speed of 80 km / h under the following conditions. Rim used: 16x6.5J Internal pressure: 210kPa Load: 4.6kN

[0201] Next, the RRC in Comparative Example 1 was set to 100, and the results were indexed based on the following formula to evaluate fuel economy. A larger value indicates lower rolling resistance and better fuel economy. Fuel economy rating=[(RRC of Comparative Example 1) / (RRC of test tire)]×100

[0202] (2) High-speed durability evaluation Each test tire is mounted on a rim (size = 16 x 6.5J), and the tire is inflated with air to adjust the internal pressure to 210 kPa. After that, the tire is mounted on a drum running test machine and a high-speed durability test is carried out in accordance with the method specified in JIS D4230:1998, and the time until the tire is damaged is measured.

[0203] Next, the result of Comparative Example 1 is set to 100, and the high-speed durability is indexed based on the following formula and evaluated as an index. A larger value indicates a longer time until damage occurs and superior high-speed durability. High-speed durability evaluation = [(Test tire results) / (Comparative example 1 results)] x 100

[0204] (3) Steering stability evaluation One test driver drives a vehicle (a domestically produced FR vehicle with an engine displacement of 2000cc) fitted with each test tire on all wheels around a dry asphalt test course at a speed of 100 km / h. Each of the 20 test drivers then performs a sensory evaluation of the handling stability during driving on a scale of 1 to 5 (the higher the number, the better) based on characteristics such as steering response, rigidity, and grip, and the total score is calculated.

[0205] Next, the result of Comparative Example 1 was set to 100, and the result was indexed according to the following formula to give an evaluation of steering stability. A larger value indicates better steering stability during high-speed driving. Steering stability evaluation = [(Test tire results) / (Comparative example 1 results)] x 100

[0206] (4) Overall performance evaluation Then, (1), (2), and (3) are added together to arrive at the overall performance evaluation.

[0207] [Table 1]

[0208] [Table 2]

[0209] [Table 3]

[0210] Although the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above embodiments. Various modifications can be made to the above embodiments within the scope of the same or equivalent to the present disclosure.

[0211] The present invention (1) is a carcass having a carcass cord; a belt including a belt cord and provided on the outer side of the carcass in the tire radial direction; A tire comprising a band code and provided with a band 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, The band code contains polyethylene terephthalate fibers, When the tread is viewed in a plane in the tire diameter direction, the intersection angle, which is the smaller of the angles formed by the tire circumferential direction and the longitudinal direction of the belt code, is greater than 0 degrees and less than 25 degrees, The belt code is composed of one or more and four or less filaments, A tire characterized in that the ratio (Dba / Dbr) of the band code diameter Dba (mm) to the belt code diameter Dbr (mm) satisfies the following formula (1). 0.5 < Dba / Dbr < 1.8 (1 formula)

[0212] The present invention (2) Is characterized in that the (Dba / Dbr) satisfies the following formula (2), and is the tire according to the present invention (1). 0.9 < Dba / Dbr < 1.7 (2 formula)

[0213] The present invention (3) Is characterized in that the structure of the belt code is any one of a 1×1 structure, a 1×2 structure, a 1×3 structure, a 1×4 structure, and a 2+2 structure, and is the tire according to the present invention (1) or the present invention (2).

[0214] The present invention (4) Is characterized in that the belt code is made of steel, and is the tire according to the present invention (1) or the present invention (2).

[0215] The present invention (5) Is characterized in that the intersection angle is less than 22 degrees, and is the tire according to the present invention (1) or the present invention (2).

[0216] The present invention (6) The tire according to the present invention (1) or (2), characterized in that the band cord diameter is more than 0.2 mm and less than 0.8 mm.

[0217] The present invention (7) is The tire is characterized in that the rubber composition forming the tread contains more than 25 parts by mass of isoprene-based rubber per 100 parts by mass of the rubber component, and is the tire described in present invention (1) or present invention (2).

[0218] The present invention (8) is The tire according to the present invention (7) is characterized in that the isoprene-based rubber is natural rubber.

[0219] The present invention (9) is The tire is characterized in that the rubber composition forming the tread contains more than 60 parts by mass of silica per 100 parts by mass of the rubber component, and is the tire according to the present invention (1) or (2).

[0220] The present invention (10) is The tire according to present invention (9) is characterized in that the particle size (average primary particle size) of the silica is more than 8 nm.

[0221] The present invention (11) is The tire according to the present invention (1) or (2) is characterized in that the amount of acetone extractables in the rubber composition forming the tread exceeds 10% by mass.

[0222] The present invention (12) is The tire is characterized in that the polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber, and is the tire according to the present invention (1) or (2).

[0223] The present invention (13) is The tire according to the present invention (1) or (2), characterized in that the silica is sustainable silica.

[0224] The present invention (14) is The tire according to the present invention (1) or (2), characterized in that the carbon black is sustainable carbon black.

[0225] The present invention (15) is The tire according to the present invention (1) or (2) is characterized in that the rubber composition forming the tread contains vegetable oil. [Explanation of symbols]

[0226] 1 tire 2 Tread 3 Sidewall 4 Chafer 5 beads 6 Inner liner 7. Carcass 8. Belt 9. Filler 10 bands CL Tire equatorial plane

Claims

1. a carcass having a carcass cord; a belt including a belt cord and provided on the outer side of the carcass in the tire radial direction; a band provided on the outer side of the belt in the tire radial direction, the band having a band cord; A tire comprising a tread provided on the outer side of the band in the tire radial direction, The band cord contains polyethylene terephthalate fibers, When the tread is viewed in a plane in the tire radial direction, an intersection angle, which is the smaller angle between the tire circumferential direction and the longitudinal direction of the belt cord, is greater than 0 degrees and less than 25 degrees, The belt cord is composed of one or more and four or less filaments, A tire characterized in that a ratio (Dba / Dbr) of the band cord diameter Dba (mm) to the belt cord diameter Dbr (mm) satisfies the following (Formula 1): 0.5<Dba / Dbr<1.8 (1 set)

2. 2. The tire according to claim 1, wherein the (Dba / Dbr) satisfies the following (2) formula: 0.9<Dba / Dbr<1.7 (2 formulas)

3. 3. The tire according to claim 1, wherein the belt cord has a structure selected from the group consisting of a 1x1 structure, a 1x2 structure, a 1x3 structure, a 1x4 structure, and a 2+2 structure.

4. 3. The tire according to claim 1, wherein the belt cord is made of steel.

5. 3. The tire according to claim 1, wherein the crossing angle is less than 22 degrees.

6. 3. The tire according to claim 1, wherein the band cord has a diameter greater than 0.2 mm and less than 0.8 mm.

7. 3. The tire according to claim 1, wherein the rubber composition forming the tread contains more than 25 parts by mass of an isoprene-based rubber per 100 parts by mass of the rubber component.

8. 8. The tire according to claim 7, wherein the isoprene-based rubber is natural rubber.

9. 3. The tire according to claim 1, wherein the rubber composition forming the tread contains more than 60 parts by mass of silica per 100 parts by mass of the rubber component.

10. The tire according to claim 9, characterized in that the particle diameter (average primary particle diameter) of the silica is greater than 8 nm.

11. 3. The tire according to claim 1, wherein the rubber composition forming the tread has an acetone extractable amount of more than 10% by mass.

12. 3. The tire according to claim 1 or claim 2, wherein the polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber.

13. 3. The tire according to claim 1, wherein the silica is sustainable silica.

14. 3. The tire according to claim 1, wherein the carbon black is sustainable carbon black.

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

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