tire

Abstract

To provide a tire with excellent dry grip performance during cornering. [Solution] The present invention relates to a tire having a tread, wherein the tread is composed of a tire rubber composition containing a rubber component including styrene-butadiene rubber and an ionic coupling agent, and has a first land portion closest to the equator and a second land portion located outside the first land portion on the vehicle side of the tire's equator, and satisfies the following (1) to (3). (1) The amount of styrene in the styrene-butadiene rubber is more than 20% by mass (2) When the land ratio of the first land area is L1 and the land ratio of the second land area is L2, L2 / L1 > 0.3 (3) (L2 - L1 × 0.3) × Total amount of styrene in the rubber component > 500

Description

[Technical Field]

[0001] This invention relates to tires. [Background technology]

[0002] Tires used in automobiles require good dry grip performance from a safety standpoint, and various types of tires have been proposed, but further improvements are desired (Patent Document 1, etc.). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2008-285524 [Overview of the project] [Problems that the invention aims to solve]

[0004] This invention has been made in view of the above-mentioned circumstances, and aims to provide a tire with excellent dry grip performance during cornering. [Means for solving the problem]

[0005] The present invention relates to a tire having a tread, wherein the tread is composed of a tire rubber composition containing a rubber component including styrene-butadiene rubber and an ionic coupling agent, and the tire has a first land portion closest to the equator and a second land portion located outside the first land portion on the vehicle side of the tire, and satisfies the following (1) to (3). (1) The amount of styrene in the styrene-butadiene rubber is more than 20% by mass (2) When the land ratio of the first land area is L1 and the land ratio of the second land area is L2, L2 / L1 > 0.3 (3) (L2 - L1 × 0.3) × Total amount of styrene in the rubber component > 500 [Effects of the Invention]

[0006] The present invention provides a tire having a tread, wherein the tread is composed of a rubber composition for tires containing a rubber component including styrene-butadiene rubber and an ionic coupling agent, and has a first land portion closest to the equator on the vehicle side of the tire's equator and a second land portion located further out than the first land portion, and satisfies the above (1) to (3), thus providing a tire with excellent dry grip performance during cornering. [Brief explanation of the drawing]

[0007] [Figure 1] This is an exploded view of the tread portion of one embodiment of the present invention. [Modes for carrying out the invention]

[0008] The above-mentioned tire is a tire having a tread, the tread being composed of a tire rubber composition containing a rubber component including styrene-butadiene rubber and an ionic coupling agent, and having a first land portion closest to the equator on the vehicle side of the tire's equator and a second land portion located further out than the first land portion, and satisfying the above conditions (1) to (3).

[0009] The mechanism by which the aforementioned effects are obtained is not clear, but it is presumed to be as follows. In a tire having a tread made of a rubber composition for tires containing an ionic coupling agent, increasing the land ratio of the tread's shoulder portion and increasing the amount of styrene in the styrene-butadiene rubber component increases the contact area between the road surface and the tread, and also increases the energy loss caused by the movement of polymer chains, making it easier to transmit force to the road surface when turning. Based on the above, it is presumed that the dry grip performance during cornering will be significantly improved.

[0010] In this specification, "rubber component" refers to a component that contributes to crosslinking, and is a solid rubber under the conditions of 1 atmosphere and 25°C. In other words, a liquid rubber under the conditions of 1 atmosphere and 25°C is not considered a "rubber component." Here, the rubber component is preferably a polymer with a weight-average molecular weight (Mw) of 100,000 or more.

[0011] The weight-average molecular weight of the rubber component is preferably 100,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and also preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. Within this range, a better effect tends to be obtained.

[0012] In this specification, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) can be determined by converting the measured values ​​obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation) to standard polystyrene equivalents.

[0013] The total styrene content in the rubber component is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and also preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less. Within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, it is preferably 13.75% by mass or more, more preferably 19.75% by mass or more, and even more preferably 23.7% by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, it is preferably 23.7% by mass or less, more preferably 19.75% by mass or less, and even more preferably 13.75% by mass or less.

[0014] Here, the total amount of styrene in the rubber component is the total amount of styrene contained in the entire rubber component (unit: mass%), and can be calculated using the formula Σ(content of each rubber component × amount of styrene in each rubber component / 100). For example, if 100% by mass of the rubber component consists of 85% by mass of styrene-butadiene rubber with a styrene content of 40% by mass, 5% by mass of styrene-butadiene rubber with a styrene content of 25% by mass, and 10% by mass of butadiene rubber with a styrene content of 0% by mass, then the total amount of styrene in the rubber component is 35.25% by mass (= 85 × 40 / 100 + 5 × 25 / 100 + 10 × 0 / 100).

[0015] In this specification, the amount of styrene in each rubber component is determined by pyrolysis gas chromatography or NMR measurement. 1 H-NMR and 13 It is calculated by 13C-NMR. The same applies to the styrene content and vinyl content of SBR described later. The amounts of these components are calculated using the complex modulus (E * Unlike physical properties such as those mentioned above, there exists a true value that is independent of the measurement method, so it is preferable to use a measurement method that is as high-precision as possible. Furthermore, while the total amount of styrene in the rubber component is calculated in accordance with the formulas described herein in the examples, it may also be analyzed from the tire using, for example, Py-GC / MS.

[0016] The above rubber components include styrene-butadiene rubber (SBR). The above-mentioned SBR is not particularly limited, and for example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc., can be used. These may be used individually or in combination of two or more types.

[0017] The glass transition temperature (Tg) of the above-mentioned SBR is preferably -10°C or lower, more preferably -20°C or lower. The lower limit of the Tg of SBR is not particularly limited, but is preferably -75°C or higher, more preferably -70°C or higher, and even more preferably -65°C or higher. When the Tg is within the above range, the effect tends to be better obtained.

[0018] In this specification, the glass transition temperature is the value measured by differential scanning calorimetry (DSC) at a heating rate of 10°C / min in accordance with JIS K7121. Furthermore, when multiple SBRs are used, the weight average value obtained from the individual glass transition temperatures and their respective mixing ratios is treated as the glass transition temperature of the SBR. For example, if 40% by mass of SBR with a Tg of -80°C is included in 100 parts by mass of the rubber component, and 40% by mass of SBR with a Tg of -40°C is included in 100 parts by mass of the rubber component, the glass transition temperature of the SBR in the rubber composition will be -60°C (=(-80×40-40×40) / (40+40)).

[0019] In the above rubber composition, the styrene content of SBR is more than 20% by mass. The styrene content of SBR is preferably 23% by mass or more, more preferably 25% by mass or more, even more preferably 27% by mass or more, and also preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. Within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, it is preferably 27.5% by mass or more, and more preferably 39.5% by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, it is preferably 39.5% by mass or less, and more preferably 27.5% by mass or less.

[0020] The styrene content of SBR refers to the styrene content of a single type of SBR if it is one type, and to the average styrene content if it is one of multiple types. The average styrene content of SBR can be calculated using the formula {Σ(content of each SBR × styrene content of each SBR)} / total content of all SBR. For example, if 85% of the rubber component is SBR with 40% styrene content and 5% is SBR with 25% styrene content, the average styrene content of the SBR is 39.2% (=(85 × 40 + 5 × 25) / (85 + 5)).

[0021] The vinyl content of SBR is preferably 30% by mass or more, more preferably 45% by mass or more, even more preferably 55% by mass or more, and also preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. When the content is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, it is preferably 38.5% by mass or more, more preferably 57% by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, it is preferably 57% by mass or less, more preferably 38.5% by mass or less.

[0022] The vinyl content of SBR (amount of 1,2-bonded butadiene units) is the ratio of vinyl bonds to the total mass of the butadiene portion in the SBR, with the total mass being 100 (unit: mass%). The formula is: vinyl content [mass%] + cis content [mass%] + trans content [mass%] = 100 [mass%]. If there is only one type of SBR, it refers to the vinyl content of that SBR; if there are multiple types, it refers to the average vinyl content. The average vinyl content of SBR can be calculated using the formula: Σ{Content of each SBR × (100 [mass%] - Styrene content of each SBR [mass%]) × Vinyl content of each SBR [mass%]} / Σ{Content of each SBR × (100 [mass%] - Styrene content of each SBR [mass%])}. For example, if 100 parts by mass of rubber component, 75 parts by mass of SBR contain 40% by mass of styrene and 30% by mass of vinyl, and 25% by mass of vinyl, If 15 parts by mass of SBR have a 20% vinyl content and the remaining 10 parts by mass are other than SBR, the average vinyl content of the SBR is 28% by mass (= {75 × (100 [mass%] - 40 [mass%]) × 30 [mass%] + 15 × (100 [mass%] - 25 [mass%]) × 20 [mass%])} / {75 × (100 [mass%] - 40 [mass%]) + 15 × (100 [mass%] - 25 [mass%])}.

[0023] Hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used as the above-mentioned SBR.

[0024] For example, SBR manufactured and sold by companies such as Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Co., Ltd. can be used as the above-mentioned SBR. Alternatively, SBR synthesized by known methods can also be used.

[0025] The above rubber component preferably includes isoprene-based rubber. Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. For NR, common types used in the rubber industry, such as SIR20, RSS#3, and TSR20, can be used. For IR, there are no particular limitations; common types used in the rubber industry, such as IR2200, can be used. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber. 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 individually or in combination of two or more types.

[0026] The above rubber component preferably includes butadiene rubber (BR). The above-mentioned BR is not particularly limited, and for example, high-cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, and BR synthesized using a rare-earth catalyst (rare-earth BR) can be used. These may be used individually or in combination of two or more. In particular, it is preferable that the BR contains high-cis BR with a cis content of 90% by mass or more. The cis content is more preferably 95% by mass or more. The cis content can be measured by infrared absorption spectroscopy.

[0027] The cis amount of the above BR refers to the cis amount of that BR if there is only one type of BR, and the average cis amount if there are multiple types. The average cis content of BR can be calculated as {Σ(content of each BR × cis content of each BR)} / total BR content. For example, if 20% of BR has a cis content of 90% and 10% has a cis content of 40% out of 100% of rubber components, the average cis content of BR is 73.3% (=(20 × 90 + 10 × 40) / (20 + 10)).

[0028] Hydrogenated butadiene polymer (hydrogenated BR) can also be used as the above-mentioned BR.

[0029] For example, products from companies such as Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation can be used as BRs.

[0030] The raw materials (monomers) for synthetic rubbers such as IR, SBR, and BR may be derived from underground resources such as petroleum and natural gas, or they may be recycled from rubber products such as tires or non-rubber products such as polystyrene. The monomers obtained by recycling (recycled monomers) are not particularly limited, but examples include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyl. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl include styrene, but are not particularly limited. In particular, it is preferable to use recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) as raw materials.

[0031] The method for producing recycled monomer is not particularly limited, and for example, it can be synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Furthermore, the method for producing recycled naphtha is not particularly limited, and for example, rubber products such as tires may be decomposed under high temperature and pressure, decomposed by microwaves, or extracted after mechanical grinding.

[0032] 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, sugars, wood chips, plant residues after obtaining useful components, plant-derived ethanol, and biomass naphtha.

[0033] The biomass-derived monomer (biomass monomer) is not particularly limited and includes biomass-derived butadiene and biomass-derived aromatic vinyl. The butadiene is 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited but includes styrene. Furthermore, the method for producing the biomass monomer is not particularly limited and includes, for example, biological and / or chemical and / or physical transformations of plants and animals. A typical biological transformation is fermentation by microorganisms, while chemical and / or physical transformations include those by catalysts, high heat, high pressure, electromagnetic waves, critical liquids, and combinations thereof.

[0034] The polymer synthesized from biomass monomer components (biomass polymer) is not particularly limited, and examples include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymers 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.

[0035] Whether the raw materials for a polymer are biomass-derived can be determined by measuring pMC (percent Modern Carbon) in accordance with ASTMD6866-10.

[0036] pMC stands for Modern Standard Reference Carbon. 14 Sample relative to C concentration14 It is the ratio of C concentration and is a value used as an index indicating the biomass ratio of a compound. The significance of this value is described below.

[0037] In one mole (6.02×10 23 pieces) of carbon atoms, there are approximately 6.02×10 11 pieces of 14 C, which is about one trillionth of ordinary carbon atoms. 14 C is called a radioactive isotope, and its half-life is 5730 years and it decreases regularly. It takes 226,000 years for all of these to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken up and immobilized by plants and the like, in fossil fuels such as coal, oil, and natural gas where more than 226,000 years are considered to have passed, all of the 14 C element has decayed. Therefore, in the 21st century, at present, fossil fuels such as coal, oil, and natural gas do not contain 14 any C element at all. Therefore, chemical substances produced from these fossil fuels also do not contain 14 any C element.

[0038] On the other hand, 14 C is constantly generated by nuclear reactions of cosmic rays in the atmosphere, and a balance is maintained between its generation and decrease due to radioactive decay. In the earth's atmospheric environment, 14 the amount of C is a constant. Therefore, the 14 C concentration of substances derived from biomass resources that are circulating in the current environment is about 1×10 -12 mol% with respect to the entire C atoms as described above. Therefore, the biomass ratio of a certain compound can be calculated using the difference between these values.

[0039] This 14 C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, 13 the C concentration ( 13 C / 12 C), 14 the C concentration ( 14 C / 12 C) is measured. In the measurement,14 As a modern standard reference for the concentration of C, the amount of cyclic carbon in nature as of 1950 14 The C concentration will be used. The specific standard material will be the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific radioactivity of carbon in this oxalic acid (per gram of carbon) will be used. 14 The radioactivity intensity of C is separated by carbon isotope, 13 The value obtained by correcting C to a constant value and applying decay correction from 1950 AD to the measurement date is the standard value. 14 This value is used as the C concentration value (100%). The ratio of this value to the value of the sample actually measured is the pMC value.

[0040] Therefore, if the rubber is made from 100% biomass-derived materials, although there are regional differences, under normal conditions it will often not reach 100, and will show a value of approximately 110 pMC. On the other hand, regarding chemical substances derived from fossil fuels such as petroleum, 14 When the C concentration is measured, it will show a value of around 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% as mentioned above.

[0041] Based on the above, using materials such as rubber with a high pMC value, that is, materials such as rubber with a high biomass ratio, in rubber compositions is preferable from an environmental protection standpoint.

[0042] In the above-mentioned tire rubber composition, the SBR content in 100% by mass of the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and also preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. When the content is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, it is preferably 50% by mass or more, more preferably 60% by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, it is preferably 60% by mass or less, more preferably 50% by mass or less.

[0043] In the above-mentioned tire rubber composition, the content of isoprene-based rubber in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and also preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. When the content is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving wear resistance, the amount is preferably 30% by mass or more, more preferably 40% by mass or more. Furthermore, from the viewpoint of improving handling stability during high-speed driving, the amount is preferably 40% by mass or less, more preferably 30% by mass or less.

[0044] In the above-mentioned rubber composition for tires, the content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and also preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. When the content is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, the amount is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0045] The above tire rubber composition may contain other rubber components in addition to SBR, isoprene-based rubber, and BR. Other usable rubber components include, for example, diene-based rubbers other than those mentioned above. Examples of diene-based rubbers other than isoprene-based rubber, BR, and SBR include styrene-isoprene butadiene rubber (SIBR), ethylene-propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). Other rubber components include butyl-based rubber and fluororubber. The rubber components may be used individually or in combination of two or more. Furthermore, these rubber components may be subjected to modification treatment or hydrogenation treatment, and stretched rubber, which has been stretched with oil, resin, liquid rubber components, etc., may also be used.

[0046] The above-mentioned rubber composition for tires contains an ionic coupling agent. Any material that reacts with silica and is modified to form ionic bonds can be used as an ionic coupling agent. More specifically, any material having a site that can react with silica and a site that can form ionic bonds can be used as an ionic coupling agent, for example, a site that reacts with silanol groups on the silica surface, such as OCR. 1 (R 1 A compound having a moiety represented by (where represents a monovalent organic group) and an ionic functional group is preferred. The above ionic functional group is not particularly limited as long as it is a functional group containing anionic species or cationic species. For example, sulfate ester base (-OSO3 - X + ), sulfonic acid base (-SO3 - X + ), phosphate ester base (-OPO(O - X + )2) Phosphosphate base (-PO(O - X + 2) Carboxylic acid base (-COO - X + ), boronic acid base (-B(O - X + )2) anionic groups such as (X +represents a cation. ), quaternary ammonium group (-(NR 35 R 36 R 37 ) + Y - Cationic groups (Y) such as (R35~R37 will be described later in the formula) - represents an anion. ) are examples. The above ionic coupling agent may have one of these ionic functional groups, or two or more. The above X + The cation represented by may be an organic ion or an inorganic ion, and is not particularly limited, but examples include metal ions such as lithium ions, sodium ions, and potassium ions, and ammonium groups. - The anion represented by may be an organic ion or an inorganic ion, and is not particularly limited, but examples include chloride ions, as described later.

[0047] In particular, the ionic coupling agent is preferably at least one selected from the group consisting of a compound represented by the following formula (1), a hydrolysate of the compound represented by the following formula (1), and a hydrolyzed condensate of the compound represented by the following formula (1).

[0048] [ka]

[0049] In formula (1), R 31 and R 32 Each of these independently represents a monovalent organic group. 33 and R 34 Each of these independently represents an organic group having a group selected from the group consisting of alkyl groups, vinyl groups, epoxy groups, styryl groups, (meth)acrylic groups, amino groups, isocyanurate groups, ureido groups, mercapto groups, sulfide groups, polyalkylene oxyalkyl groups, carboxyl groups, sulfate ester bases, sulfonic acid bases, phosphate ester bases, phosphonic acid bases, carboxylic acid bases, boronic acid salts, and quaternary ammonium groups, and the above R 34At least one of the groups is an organic group having a group selected from the group consisting of sulfate ester bases, sulfonic acid bases, phosphate ester bases, phosphonic acid bases, carboxylic acid bases, boronic acid bases, and quaternary ammonium groups. m independently represents an integer from 0 to 2. n represents an integer. In this specification, an organic group means a group having one or more carbon atoms.

[0050] The hydrolysate of the compound represented by formula (1) is a compound in which at least some of the substituents on the silicon atom of the compound represented by formula (1) have been hydrolyzed to form a silanol group. Furthermore, the hydrolysis condensate of the compound represented by formula (1) is a compound obtained by the condensation of two or more compounds selected from the group consisting of the compound represented by formula (1) and the hydrolysis product of the compound represented by formula (1).

[0051] In formula (1), m is preferably 1 or 2, and more preferably 2. In equation (1), n ​​is preferably an integer between 2 and 20.

[0052] R in equation (1) 31 and R 32 The monovalent organic group preferably has 1 to 6 carbon atoms. R 31 and R 32 The C1-C6 organic group in the formula may be linear, branched, or cyclic. Examples of C1-C6 organic groups include alkyl groups and alkenyl groups, with alkyl groups being preferred. Examples of C1-C6 alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, and cyclohexyl groups.

[0053] R in equation (1) 31 and R 32Each of these is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, even more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0054] R in equation (1) 33 Each of these is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, even more preferably a methyl group or an ethyl group, and particularly preferably a methyl group.

[0055] R in equation (1) 34 Preferably, at least one of the organic groups has a quaternary ammonium group. Examples of groups having a quaternary ammonium group include the group represented by the following formula. [ka]

[0056] In the formula, R 35 ~R 37 Each of these independently represents a monovalent organic group. 38 Each of these independently represents a divalent organic group. - k represents an anion. k represents an integer.

[0057] R 35 ~R 37 Examples of monovalent organic groups include monovalent hydrocarbon groups, such as alkyl groups having 1 to 18 carbon atoms and alkenyl groups having 2 to 12 carbon atoms. R 35 ~R 37 The number of carbon atoms is preferably 1 to 12, more preferably 1 to 7, even more preferably 1 to 5, and particularly preferably 1 to 3. R 35 ~R 37 The monovalent organic group is particularly preferably a methyl group or an ethyl group.

[0058] R 38Examples of divalent organic groups include divalent hydrocarbon groups, such as alkylene groups having 1 to 12 carbon atoms and alkenylene groups having 2 to 12 carbon atoms. R 38 The number of carbon atoms is preferably 1 to 12, more preferably 1 to 7, even more preferably 1 to 5, and particularly preferably 1 to 3. R 38 The divalent organic group is particularly preferably a methylene group or an ethylene group.

[0059] k is preferably 0 to 5, more preferably 0 to 3, even more preferably 0 to 1, and particularly preferably 0.

[0060] Y - These are not particularly limited, and include, for example, halide ions (chloride ions, bromide ions, iodide ions, etc.); carboxylate ions (formate ions, acetate ions, trifluoroacetate ions, lactate ions, propionate ions, benzoate ions, oxalate ions, succinate ions, stearate ions, etc.); methyl sulfate ions (alkyl sulfate ions, etc.); sulfonate ions (methanesulfonate ions, benzenesulfonate ions, trifluoromethanesulfonate ions, toluenesulfonate ions, naphthalenesulfonate ions, nitrobenzenesulfonate ions) Examples include dodecylbenzenesulfonate ions, ethanesulfonate ions, etc.; sulfonate imide ions (bis(trifluoromethanesulfonic acid)imide ions, etc.); borate ions (tetrafluoroborate ions, tetraphenylborate ions, butyltriphenylborate ions, etc.); phosphate ions (hexafluorophosphate ions, etc.); antimonate ions (hexafluoroantimonate ions, etc.); arsenate ions (hexafluoroarsenate ions, etc.); perhalate ions (perchlorate ions, periodate ions, etc.); thiocyanate ions, nitrate ions, etc.

[0061] Among the compounds represented by formula (1) above, the hydrolysates of the compounds represented by formula (1) above, and the hydrolyzed condensates of the compounds represented by formula (1) above, the compound represented by the following formula (1-1) is preferable from the viewpoint of obtaining a better effect.

[0062] [Chemical]

[0063] In formula (1-1), R 35 ~R 37 each independently represents the same group as the above R 35 ~R 37 . R 38 each independently represents the same group as the above R 38 . Y - each independently represents the same anion as the above Y - . k each independently represents the same integer as the above k.

[0064] In formula (1-1), the preferred examples of R 35 ~R 37 , R 38 , Y - , k are also the same as above.

[0065] When the ionic coupling agent has a salt structure such as a quaternary ammonium salt, such as the compound represented by the formula (1-1), a better effect can be obtained. The compound represented by the formula (1) preferably has a quaternary ammonium salt structure. The ionic coupling agent is more preferably a quaternary ammonium salt.

[0066] For the above ionic coupling agent, commercially available products such as Shin-Etsu Chemical Co., Ltd.'s X-12-1126, KBM-9418-40, etc. can be used.

[0067] In the above rubber composition for tires, the total content of the above ionic coupling agent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 7 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. When within the above range, the effect tends to be obtained more favorably. On the other hand, from the viewpoint of improving the overall performance of wet grip performance and dry grip performance, the amount is preferably 6 parts by mass or more, more preferably 7 parts by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, the amount is preferably 7 parts by mass or less, more preferably 6 parts by mass or less.

[0068] The above-mentioned rubber composition for tires may contain a filler. The filler is not particularly limited, and materials known in the rubber field can be used. Examples include inorganic fillers such as carbon black, silica, calcium carbonate, talc, alumina, clay, magnesium sulfate, aluminum hydroxide, aluminum oxide, and mica, as well as biochar (BIO CHAR); and poorly dispersible fillers. Among these, carbon black and silica are preferred, with silica being more preferred, from the viewpoint of obtaining better results.

[0069] In the above-mentioned tire rubber composition, the silica that can be used is not particularly limited, and common silica used in the tire industry can be used, such as silica prepared by a dry process (anhydrous silica) or silica prepared by a wet process (hydrated silica). The raw material for silica is not particularly limited, and may be a mineral-derived raw material such as quartz, or a biological-derived raw material such as rice husks (for example, silica made from biomass materials such as rice husks), or silica recycled from products containing silica may be used. Among these, hydrated silica prepared by a wet process is preferred because it has a high silanol group content. These silicas may be used individually or in combination of two or more types.

[0070] Silica derived from biomass materials can be obtained, for example, by extracting silicates from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then using these silicates to react with sulfuric acid in the same way as conventional wet silica, the precipitate of silicon dioxide is filtered, washed with water, dried, and pulverized.

[0071] Silica recycled from products containing silica can be, for example, silica recovered from products containing silica such as electronic components such as semiconductors, tires, desiccants, and filter materials such as diatomaceous earth. The method of recovery is not particularly limited and includes pyrolysis, decomposition by electromagnetic waves, etc. Among them, silica recovered from electronic components such as semiconductors or tires is preferred.

[0072] When silica crystallizes, it becomes insoluble in water and the silicic acid that is its component cannot be utilized. By controlling the combustion temperature and combustion time, crystallization of the silica in rice husk ash can be suppressed (see, for example, Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, p. 216-222, etc.).

[0073] Amorphous silica extracted from rice husks can be those commercially available from companies such as Wilmar.

[0074] The CTAB specific surface area (cetyltrimethylammonium bromide adsorption specific surface area, CTAB) of silica is preferably 100 m 2 / g or more, more preferably 160 m 2 / g or more, still more preferably 220 m 2 / g or more. Also, the upper limit of the CTAB of silica is not particularly limited, but is preferably 350 m 2 / g or less, more preferably 300 m 2 / g or less, still more preferably 260 m 2 / g or less. Although the mechanism by which more effects are obtained within the above range is not clear, it is presumed that the followability to the road surface is improved, so the dry grip performance during turning is improved. In this specification, the CTAB specific surface area of silica is a value measured in accordance with JIS K6217-3.

[0075] The average particle size of silica is preferably 24 nm or less, more preferably 22 nm or less, even more preferably 20 nm or less, and even more preferably 17 nm or less, and also preferably 6 nm or more, more preferably 9 nm or more, and even more preferably 12 nm or more. Within the above range, a better effect tends to be obtained.

[0076] In this specification, the method for measuring the average particle size of silica is transmission electron microscopy (TEM) observation. Specifically, silica particles are photographed with a transmission electron microscope, and if the particle shape is spherical, the diameter of the sphere is defined as the particle size; if it is needle-shaped or rod-shaped, the shorter axis is defined as the particle size; if it is irregularly shaped, the average particle size from the center is defined as the particle size; and the average particle size of 100 fine particles is defined as the average particle size.

[0077] The carbon blacks mentioned above are not particularly limited and include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. The raw materials for carbon black may be biomass materials such as lignin and vegetable oil, or pyrolysis oil obtained by thermal decomposition of waste tires. The manufacturing method for carbon black may be combustion such as the furnace method, hydrothermal carbonization (HTC), or thermal decomposition of methane such as the thermal black method. 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 Corporation, etc. Carbon black may be used alone or in combination of two or more types.

[0078] The specific surface area of ​​carbon black (CTAB) is 50 m². 2 Preferably 80m / g or more. 2 More preferably 110m / g or more, 2 A value of 1 / g or more is even more preferable. Also, the above CTAB is 200m 2 Preferably less than / g, 180m 2 More preferably less than / g, 160m 2A value of less than / g is even more preferable. Within the above range, a better effect tends to be obtained. The CTAB specific surface area of ​​carbon black is a value measured in accordance with JIS K6217-3.

[0079] The magnesium sulfate mentioned above is preferably anhydrous magnesium sulfate, magnesium sulfate dihydrate, or magnesium sulfate trihydrate, with anhydrous magnesium sulfate being more preferred.

[0080] Examples of the poorly dispersible fillers mentioned above include short fibers and gel-like compounds. Among these, short fibers are preferred.

[0081] Examples of short fibers that can be used include organic short fibers and inorganic short fibers. Specific examples of organic short fibers include nanocellulose such as cellulose nanofibers (CNF) and cellulose nanocrystals (CNC); biomass nanomaterials such as chitin nanofibers and chitosan nanofibers; and specific examples of inorganic short fibers include metal fibers and glass fiber systems. Commercially available products include those from Nippon Paper Industries Co., Ltd. and Sugino Machine Co., Ltd. These may be used individually or in mixtures of two or more. Among these, organic short fibers are preferred, and nanocellulose is more preferred.

[0082] The particle size of the nanocellulose is preferably 10 nm or larger, more preferably 20 nm or larger, even more preferably 25 nm or larger, and particularly preferably 28 nm or larger. It is also preferably 50 nm or smaller, more preferably 40 nm or smaller, even more preferably 35 nm or smaller, and particularly preferably 32 nm or smaller. When the particle size is within the above range, a better effect tends to be obtained.

[0083] The particle size of nanocellulose is the average fiber diameter measured by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray scattering data analysis, and pore electrical resistance method (Culter principle method). In this specification, the average fiber diameter of nanocellulose (cellulose fiber) is typically the average fiber diameter of an aggregate of cellulose fibers formed by the aggregation of cellulose molecules.

[0084] In the above-mentioned rubber composition for tires, the content of fillers (total amount of fillers such as silica and carbon black) is preferably 65 parts by mass or more, more preferably 95 parts by mass or more, even more preferably 125 parts by mass or more, and preferably 180 parts by mass or less, more preferably 160 parts by mass or less, and even more preferably 140 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving wear resistance, the amount is preferably 85 parts by mass or more, more preferably 95 parts by mass or more, even more preferably 125 parts by mass or more, even more preferably 130 parts by mass or more, and even more preferably 145 parts by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, the amount is preferably 145 parts by mass or less, more preferably 130 parts by mass or less, even more preferably 125 parts by mass or less, even more preferably 95 parts by mass or less, and even more preferably 85 parts by mass or less.

[0085] In the above-mentioned rubber composition for tires, the silica content is preferably 70 parts by mass or more, more preferably 90 parts by mass or more, even more preferably 100 parts by mass or more, and even more preferably 110 parts by mass or more, and also preferably 160 parts by mass or less, more preferably 140 parts by mass or less, and even more preferably 120 parts by mass or less. When the silica content is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving wet grip performance, the amount is preferably 80 parts by mass or more, more preferably 110 parts by mass or more, even more preferably 120 parts by mass or more, and even more preferably 130 parts by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, the amount is preferably 130 parts by mass or less, more preferably 120 parts by mass or less, even more preferably 110 parts by mass or less, and even more preferably 80 parts by mass or less.

[0086] In the above rubber composition, it is preferable that the silica content / total styrene content in the rubber component > 5. In this case, the value of (left side) is preferably 6.0 or higher, more preferably 7.0 or higher, even more preferably 8.0 or higher, and also preferably 16 or lower, more preferably 13 or lower, and even more preferably 10 or lower. When it is within the above range, a better effect tends to be obtained. In this relationship, the silica content is expressed as the content per 100 parts by mass of the rubber component (unit: parts by mass), and the total styrene content is expressed as the content in 100% by mass of the rubber component (unit: mass%).

[0087] When the above tire rubber composition contains carbon black, the carbon black content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and also preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. Within the above range, a better effect tends to be obtained.

[0088] When the above tire rubber composition contains magnesium sulfate, the magnesium sulfate content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and also preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. Within the above range, a better effect tends to be obtained.

[0089] When the above tire rubber composition contains a poorly dispersible filler, the content of the poorly dispersible filler is preferably 1 part by mass or more, more preferably 5 parts by mass or more, per 100 parts by mass of the rubber component. The content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0090] If the above tire rubber composition contains silica, it is preferable that it further contains a silane coupling agent. The silane coupling agent is not particularly limited and any known in the rubber field can be used, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl) trisulfide, bis(4-trimethoxysilylbutyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, Examples include sulfide compounds such as N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto compounds such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z from Momentive; vinyl compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Among these, mercapto compounds are preferred. Commercially available products include those from companies such as Degussa, Momentive, Shin-Etsu Chemical Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd. These can be used individually or in combination of two or more types.

[0091] In addition to compounds containing a mercapto group, compounds in which the mercapto group is protected by a protecting group (for example, compounds represented by the following formula (S1)) can also be used as mercapto-silane coupling agents.

[0092] Particularly suitable mercapto-silane coupling agents include silane coupling agents represented by the following formula (S1), and silane coupling agents containing a bonding unit A shown in the following formula (I) and a bonding unit B shown in the following formula (II). [ka] (In the formula, R 1001 -Cl, -Br, -OR 1006 -O(O=)CR 1006 , -ON=CR 1006 R 1007 , -NR 1006 R 1007 and -(OSiR 1006 R 1007 ) h (OSiR 1006 R 1007 R 1008 A monovalent group (R) selected from ) 1006 , R 1007 and R 1008 They may be the same or different, and each is a hydrogen atom or a monovalent hydrocarbon group with 1 to 18 carbon atoms, and the average value of h is 1 to 4. 1002 is R 1001 , hydrogen atom or monovalent hydrocarbon group having 1 to 18 carbon atoms, R 1003 is -[O(R 1009 O) j ]-group(R 1009 is an alkylene group with 1 to 18 carbon atoms, and j is an integer from 1 to 4. ), R 1004 R is a divalent hydrocarbon group having 1 to 18 carbon atoms. 1005 (where represents a monovalent hydrocarbon group with 1 to 18 carbon atoms, and x, y, and z are numbers that satisfy the relationships x + y + 2z = 3, 0 ≤ x ≤ 3, 0 ≤ y ≤ 2, and 0 ≤ z ≤ 1.) [ka] [ka] (In the formula, v is a non-negative integer and w is a non-negative integer. 11 R represents hydrogen, halogen, branched or unbranched C1-C30 alkyl group, branched or unbranched C2-C30 alkenyl group, branched or unbranched C2-C30 alkynyl group, or an alkyl group in which the terminal hydrogen is substituted with a hydroxyl group or a carboxyl group. 12 R represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, or a branched or unbranched alkynylene group having 2 to 30 carbon atoms. 11 and R 12 (They may form a ring structure.)

[0093] In equation (S1), R 1005 , R 1006 , R 1007 and R 1008 Each of these is preferably independently selected from the group consisting of linear, cyclic, or branched alkyl groups, alkenyl groups, aryl groups, and aralkyl groups having 1 to 18 carbon atoms. 1002 If is a monovalent hydrocarbon group having 1 to 18 carbon atoms, it is preferably a group selected from the group consisting of linear, cyclic, or branched alkyl groups, alkenyl groups, aryl groups, and aralkyl groups. 1009 The alkylene group is preferably linear, cyclic, or branched, and is particularly preferred to be linear. 1004 Examples of these include alkylene groups having 1 to 18 carbon atoms, alkenylene groups having 2 to 18 carbon atoms, cycloalkylene groups having 5 to 18 carbon atoms, cycloalkylalkylene groups having 6 to 18 carbon atoms, arylene groups having 6 to 18 carbon atoms, and aralkylene groups having 7 to 18 carbon atoms. The alkylene groups and alkenylene groups may be linear or branched, and the cycloalkylene groups, cycloalkylalkylene groups, arylene groups, and aralkylene groups may have functional groups such as lower alkyl groups on their rings. 1004Preferably, the alkylene group has 1 to 6 carbon atoms, and in particular, linear alkylene groups such as methylene, ethylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene groups are preferred.

[0094] R in equation (S1) 1002 , R 1005 , R 1006 , R 1007 and R 1008 Specific examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclohexenyl group, phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, phenethyl group, naphthylmethyl group, and the like. R in equation (S1) 1009 Examples of linear alkylene groups include methylene, ethylene, n-propylene, n-butylene, and hexylene groups, while examples of branched alkylene groups include isopropylene, isobutylene, and 2-methylpropylene groups.

[0095] Specific examples of silane coupling agents represented by formula (S1) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, and 2-lauroylthioethyltrimethoxysilane. These may be used individually or in combination of two or more. Among them, 3-octanoylthiopropyltriethoxysilane is particularly preferred.

[0096] In a silane coupling agent containing a bonding unit A represented by formula (I) and a bonding unit B represented by formula (II), the content of bonding unit A is preferably 30 mol% or more, more preferably 50 mol% or more, preferably 99 mol% or less, and more preferably 90 mol% or less. The content of bonding unit B is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, preferably 70 mol% or less, more preferably 65 mol% or less, and even more preferably 55 mol% or less. The total content of bonding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%. The content of bonding units A and B includes the amount when bonding units A and B are located at the ends of the silane coupling agent. The form of bonding units A and B when they are located at the ends of the silane coupling agent is not particularly limited, as long as they form units corresponding to formulas (I) and (II) that represent bonding units A and B.

[0097] R in equations (I) and (II)11 Examples of halogens include chlorine, bromine, and fluorine. Examples of branched or unbranched alkyl groups with 1 to 30 carbon atoms include methyl and ethyl groups. Examples of branched or unbranched alkenyl groups with 2 to 30 carbon atoms include vinyl and 1-propenyl groups. Examples of branched or unbranched alkynyl groups with 2 to 30 carbon atoms include ethynyl and propynyl groups.

[0098] R in equations (I) and (II) 12 Regarding branched or unbranched alkylene groups with 1 to 30 carbon atoms, examples include ethylene and propylene groups. Regarding branched or unbranched alkenylene groups with 2 to 30 carbon atoms, examples include vinylene and 1-propenylene groups. Regarding branched or unbranched alkylene groups with 2 to 30 carbon atoms, examples include ethynylene and propynylene groups.

[0099] In a silane coupling agent containing a bonding unit A represented by formula (I) and a bonding unit B represented by formula (II), the sum of the number of repeats of bonding unit A (v) and the number of repeats of bonding unit B (w), (v+w), is preferably in the range of 3 to 300.

[0100] In the above-mentioned rubber composition for tires, the content of the silane coupling agent is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, and even more preferably 6 parts by mass or more, and also preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of silica. When the content is within the above range, a better effect tends to be obtained.

[0101] The above-mentioned rubber composition for tires preferably contains a resin as a plasticizer. Resin is a material that imparts plasticity to rubber components, and the concept includes both liquid resins and solid resins under the same conditions of 1 atmosphere and 25°C. The resin may be used alone, or two or more types may be used in combination. In this specification, resin and rubber (rubber component or liquid rubber) are considered different materials.

[0102] The resin is not particularly limited, but resins commonly used in the tire industry can be used. Examples include adhesive resins such as C5 resins, C9 resins, C5C9 resins, aromatic vinyl resins, dicyclopentadiene resins, coumarone resins, indene resins, terpene resins, rosin resins, and phenolic resins. These resins may be used individually or in combination of two or more.

[0103] Among the above resins, at least one selected from the group consisting of dicyclopentadiene resins, aromatic vinyl resins, and terpene resins is preferred, from the viewpoint of obtaining better effects.

[0104] C5 resins refer to resins obtained by polymerizing C5 fractions, and may be hydrogenated or modified versions of these resins. Examples of C5 fractions include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, isoprene, pentane, isopentane, neopentane, pentene, and pentadiene. These C5 resins may be used individually or in combination of two or more types.

[0105] C9 resins refer to resins obtained by polymerizing a C9 fraction, and may be obtained by polymerizing the C9 fraction alone, or as copolymers obtained by copolymerizing the C9 fraction with other components. They may also be hydrogenated or modified. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, coumarone, indene, and methylindene. These C9 resins may be used individually or in combination of two or more types.

[0106] C5C9 resins refer to resins obtained by copolymerizing the C5 fraction and the C9 fraction, and may be hydrogenated or modified versions of these resins. As C5C9 petroleum resins, for example, those commercially available from Tosoh Corporation, LUHUA, etc., can be used. These C5C9 resins may be used individually or in combination of two or more types.

[0107] Aromatic vinyl resins refer to resins containing aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and p-chlorostyrene as the most abundant monomer component, and may also be hydrogenated or modified versions of these compounds. For aromatic vinyl resins, α-methylstyrene or a homopolymer of styrene, or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, due to their economical nature, ease of processing, and excellent heat generation properties. Aromatic vinyl resins that can be used are commercially available from companies such as Kraton, Eastman Chemical Company, and Mitsui Chemicals, Inc. These aromatic vinyl resins may be used individually or in combination of two or more types.

[0108] Dicyclopentadiene resins refer to resins containing cyclopentadiene (CPD) or dicyclopentadiene (DCPD) as monomer components, and may be hydrogenated or modified. Examples of dicyclopentadiene resins include DCPD / C9 resins containing dicyclopentadiene and C9 fraction as monomer components (these DCPD / C9 resins may be hydrogenated or modified), with DCPD / C9 resins containing dicyclopentadiene and styrene as monomer components being preferred, and DCPD / C9 resins containing dicyclopentadiene, styrene, and indene as monomer components being particularly preferred. Dicyclopentadiene resins that are commercially available from companies such as ExxonMobil, ENEOS Corporation, Nippon Zeon Corporation, and Maruzen Petrochemical Co., Ltd. can be used. These dicyclopentadiene resins may be used individually or in combination of two or more types.

[0109] Coumarone-based resins refer to resins containing coumarone as a monomer component, and may be hydrogenated or modified resins. Examples of coumarone resins include coumarone-indene resins containing coumarone and indene as monomer components, and coumarone-indene-styrene resins containing coumarone, indene, and styrene as monomer components. These coumarone-based resins may be used individually or in combination of two or more types.

[0110] Indene resins refer to resins containing indene as a monomer component, and may be hydrogenated or modified resins. Examples of indene resins include coumarone-indene resins containing coumarone and indene as monomer components, and coumarone-indene-styrene resins containing coumarone, indene, and styrene as monomer components. These indene resins may be used individually or in combination of two or more types.

[0111] Terpene resins are resins that contain terpene compounds such as α-pinene, β-pinene, limonene, and dipentene as the most abundant monomer component, and may be hydrogenated or modified versions of these compounds. Specific examples of terpene resins include, for example, polyterpene resins containing only one or more of the aforementioned terpene compounds as monomer components; aromatically modified terpene resins containing the aforementioned terpene compounds and aromatic compounds as monomer components; and terpene-phenol resins containing the aforementioned terpene compounds and phenolic compounds as monomer components. Examples of aromatic compounds that serve as monomer components in aromatically modified terpene resins include styrene, α-methylstyrene, vinyltoluene, and divinyltoluene. Examples of phenolic compounds that serve as monomer components in terpene-phenol resins include phenol, bisphenol A, cresol, and xylenol. These terpene resins may be used individually or in combination of two or more types.

[0112] Rosin-based resins refer to resins containing rosin acid compounds such as abietic acid, neoabietic acid, palastic acid, and isopimal acid, and may be hydrogenated or modified versions of these compounds. Rosin-based resins are not particularly limited, but examples include natural resin rosin and rosin-modified resins obtained by hydrogenation, disproportionation, dimerization, esterification, etc. These rosin-based resins may be used individually or in combination of two or more types.

[0113] Phenolic resins are resins that contain phenol compounds such as phenol and cresol as the most abundant monomer component. Phenolic resins are not particularly limited, but examples include phenol-formaldehyde resins, alkylphenol-formaldehyde resins, alkylphenol-acetylene resins, and oil-modified phenol-formaldehyde resins. These phenolic resins may be used individually or in combination of two or more types.

[0114] The resin may be a modified resin (functionalized resin) into which functional groups have been introduced. Modified resins can be produced by known methods, such as slurry methods and metathesis methods. Specifically, they can be produced, for example, by reacting a polymer that forms the polymer backbone of the modified resin with a functional compound that allows for the introduction of functional groups, using known methods.

[0115] The polymer forming the polymer backbone is not particularly limited and may be, for example, the C5 resin, aromatic resin, or terpene resin mentioned above, or other resins. These may be used alone or in combination of two or more. Among these, aromatic resins are preferred, α-methylstyrene resins are more preferred, and styrene-α-methylstyrene resin (a copolymer of styrene and α-methylstyrene) is even more preferred.

[0116] The functional group is preferably one containing at least one element selected from the group consisting of oxygen, silicon, and nitrogen, and more preferably one containing silicon.

[0117] Commercially available resins from companies such as Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0118] When the above tire rubber composition contains resin, the resin content (total amount of resin in a solid state and resin in a liquid state under 1 atmosphere and 25°C conditions) is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and also preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. Within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, the amount is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more. Furthermore, from the viewpoint of improving fuel efficiency, the amount is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less.

[0119] When the above tire rubber composition contains a resin in a solid state under conditions of 1 atmosphere and 25°C, the content of the solid resin is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and also preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0120] When the above tire rubber composition contains a resin in a liquid state under conditions of 1 atmosphere and 25°C, the content of the resin in a liquid state is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and also preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. When the content is within the above range, a better effect tends to be obtained. Furthermore, the amount of resin contained in the liquid state includes the amount of resin contained in the resin-stretched rubber.

[0121] The above-mentioned rubber composition for tires may also contain plasticizers other than the above-mentioned resin.

[0122] In this specification, "plasticizer" refers to a material that imparts plasticity to rubber components, and is a concept that includes both liquid plasticizers under conditions of 1 atmosphere and 25°C, and solid plasticizers under conditions of 1 atmosphere and 25°C. Examples of plasticizers other than resins include oils, liquid rubber, and ester-based plasticizers. Among these, liquid rubber is preferred. These plasticizers may be derived from mineral resources such as petroleum and natural gas, from biomass, or from naphtha recycled from rubber or non-rubber products. Alternatively, low molecular weight hydrocarbon components obtained by thermal decomposition and extraction of used tires or products containing various components may be used as plasticizers. These plasticizers may be used individually or in combination of two or more.

[0123] Examples of oils include mineral oil, vegetable oil, and animal oil. From a life cycle assessment perspective, waste oil used in rubber mixers and engines, or refined waste cooking oil used in restaurants, may also be used.

[0124] In this specification, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oils (mineral oil), naphthenic oils, and aromatic oils. Specific examples of mineral oil include MES (Mild Extract Sollvates), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract). Furthermore, for environmental reasons, oils with a low content of polycyclic aromatic compounds (PCA) can be used. Examples of such low-PCA oils include MES, TDAE, and heavy naphthenic oils.

[0125] In this specification, vegetable oils include, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice 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. Furthermore, vegetable oils may also include refined oils obtained by refining the above oils (such as salad oil), transesterified oils obtained by transesterifying the above oils, hydrogenated oils obtained by hydrogenating the above oils, thermally polymerized oils obtained by thermally polymerizing the above oils, oxidized polymerized oils obtained by oxidizing the above oils, and waste cooking oils recovered from use as edible oils. Note that vegetable oils may be liquid or solid at 25°C. These vegetable oils may be used individually or in combination of two or more types.

[0126] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably contains triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin and a fatty acid are ester-bonded. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a polymer of three or more. Note that acylglycerols of two or more forms can be obtained by thermal polymerization, oxidative polymerization, etc. Also, the acylglycerol may be a liquid or a solid at 25°C.

[0127] The method for confirming whether the acylglycerol is contained in the tire rubber composition is not particularly limited, 1 This can be confirmed by 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, it is measured at room temperature. 1When 1H-NMR was measured and the tetramethylsilane (TMS) signal was set to 0.00 ppm, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm. These signals are presumed to originate from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0128] The aforementioned fatty acids are not particularly limited and may be either unsaturated or saturated fatty acids. 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.

[0129] In particular, it is desirable that the fatty acid contains fatty acids with few double bonds, i.e., saturated fatty acids or monounsaturated fatty acids, and oleic acid is preferred. As a vegetable oil containing such fatty acids, for example, a vegetable oil containing saturated fatty acids or monounsaturated fatty acids may be used, or a vegetable oil that has been modified by transesterification or other means may be used. Furthermore, in order to produce a vegetable oil containing such fatty acids, plants may be improved by breeding, genetic modification, genome editing, etc.

[0130] As for the oil, commercially available products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kosan Co., Ltd., and Nisshin Oillio Group Ltd. can be used.

[0131] As the liquid rubber, at least one diene-based (co)polymer selected from the group consisting of butadiene, isoprene, styrene, farnesene, and their derivatives can be used. Specific examples include liquid diene-based polymers such as liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), liquid farnesene polymer, and liquid farnesene-butadiene copolymer. Among these, liquid IR is preferred.

[0132] The liquid rubber may be modified with functional groups that interact with silica, or its terminals and / or main chain may be modified with functional groups containing at least one element selected from the group consisting of oxygen, nitrogen, silicon, and phosphorus. The liquid rubber may also be unhydrogenated or hydrogenated.

[0133] In the above-mentioned rubber composition for tires, the content of plasticizers (total amount of plasticizers such as resin and liquid rubber) is preferably 20 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more, per 100 parts by mass of the rubber component, and also preferably 110 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 70 parts by mass or less. When the content is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, the amount is preferably 33 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 43 parts by mass or more, even more preferably 50 parts by mass or more, even more preferably 53 parts by mass or more, even more preferably 55 parts by mass or more, even more preferably 60 parts by mass or more, and even more preferably 70 parts by mass or more. Furthermore, from the viewpoint of improving wear resistance, the amount is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 55 parts by mass or less, even more preferably 53 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 43 parts by mass or less, even more preferably 40 parts by mass or less, and even more preferably 33 parts by mass or less.

[0134] In the above rubber composition, it is preferable that the total amount of styrene in the rubber component × (plasticizer content + silica content) / 100 > 50. In this case, the value of (left side) is preferably 65 or less, more preferably 60 or less, and even more preferably 55 or less. When it is within the above range, a better effect tends to be obtained. In this relationship, the total styrene content is the content per 100% by mass of the rubber component (unit: mass%), while the plasticizer and silica content are the content per 100 parts by mass of the rubber component (unit: parts by mass).

[0135] When the above tire rubber composition contains a solid plasticizer in a solid state under conditions of 1 atmosphere and 25°C, the content of the solid resin is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and also preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0136] When the above tire rubber composition contains a liquid plasticizer in a liquid state under conditions of 1 atmosphere and 25°C, the content of the liquid plasticizer is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and also preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained. Furthermore, the liquid plasticizer content includes the amount of oil contained in the oil-stretched rubber and the amount of liquid resin in the resin-stretched rubber that has been stretched with liquid resin.

[0137] When the above tire rubber composition contains liquid rubber in a liquid state under conditions of 1 atmosphere and 25°C, the content of the liquid rubber is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and 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, per 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0138] When the above tire rubber composition contains oil in a liquid state under conditions of 1 atmosphere and 25°C, the oil content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and also 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, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained. Note that the oil content also includes the amount of oil contained in the oil-applied rubber.

[0139] The above-mentioned tire rubber composition may contain a fatty acid derivative.

[0140] Examples of the above-mentioned fatty acid derivatives include fatty acid metal salts, amide esters, fatty acid esters, fatty acid amides, mixtures of fatty acid metal salts and amide esters, and mixtures of fatty acid metal salts and fatty acid amides. These may be used individually or in combination of two or more. In particular, it is preferable that at least one is selected from the group consisting of fatty acid metal salts, amide esters, and mixtures of fatty acid metal salts and amide esters or fatty acid amides, more preferably fatty acid metal salts, mixtures of fatty acid metal salts and fatty acid amides, and even more preferably a mixture of fatty acid metal salts and fatty acid amides.

[0141] The fatty acids that make up the fatty acid metal salt are not particularly limited, but include saturated or unsaturated fatty acids (preferably saturated or unsaturated fatty acids having 6 to 28 carbon atoms (more preferably 10 to 25 carbon atoms, and even more preferably 14 to 20 carbon atoms)). Examples include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, behenic acid, and nervonic acid. These can be used individually or in combination of two or more. Among these, saturated fatty acids are preferred, and saturated fatty acids having 14 to 20 carbon atoms are more preferred.

[0142] Examples of metals that make up fatty acid metal salts include alkali metals such as potassium and sodium, alkaline earth metals such as magnesium, calcium and barium, zinc, nickel, and molybdenum. These may be used individually or in combination of two or more. Among these, zinc and calcium are preferred.

[0143] Examples of amide esters include fatty acid amide esters, which are composed of the saturated or unsaturated fatty acids mentioned above. These may be used individually or in combination of two or more types.

[0144] Examples of fatty acid esters include fatty acid esters composed of the saturated or unsaturated fatty acids mentioned above. These may be used individually or in combination of two or more types.

[0145] The fatty acid amide can be either saturated or unsaturated. These may be used individually or in combination of two or more. Examples of saturated fatty acid amides include N-(1-oxooctadecyl)sarcosinamide, stearic acid amide, and behenic acid amide. Examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide.

[0146] Specific examples of mixtures of fatty acid metal salts and amide esters include Aflux16, manufactured by Rhein Chemie, which is a mixture of fatty acid calcium salt and amide ester.

[0147] Specific examples of mixtures of fatty acid metal salts and fatty acid amides include WB16, manufactured by Structol, which is a mixture of fatty acid calcium and fatty acid amide.

[0148] Examples of the above-mentioned fatty acid derivatives include products from companies such as Rhein Chemie and Structol.

[0149] The content of the above fatty acid derivative is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, and even more preferably 6 parts by mass or more, per 100 parts by mass of the rubber component, and also preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0150] The above-mentioned rubber composition for tires may contain vulcanized rubber particles. Vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the viewpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. These may be used individually or in combination of two or more types.

[0151] The vulcanized rubber particles are not particularly limited and may be either unmodified or modified vulcanized rubber particles.

[0152] Commercially available vulcanized rubber particles can be used, for example, products from Lehigh, Muraoka Rubber Industries, Ltd., and others.

[0153] In the above tire rubber composition, the content of vulcanized rubber particles is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of rubber component, and also 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. When the content is within the above range, a better effect tends to be obtained.

[0154] The above-mentioned rubber composition for tires preferably contains an anti-aging agent from the viewpoint of crack resistance, ozone resistance, etc.

[0155] While not particularly limited, examples of anti-aging agents include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; 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'-ditril-p-phenylenediamine. Examples include p-phenylenediamine-based antioxidants such as methyl amine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-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, with polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline being more preferred. Commercially available products include those from companies such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis.

[0156] In the above-mentioned rubber composition for tires, the content of the anti-aging agent is preferably 2.0 parts by mass or more, more preferably 4.5 parts by mass or more, per 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 6 parts by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0157] The above-mentioned rubber composition for tires may contain stearic acid. In the above-described rubber composition for tires, the stearic acid content is preferably 1.0 part by mass or more, more preferably 2.0 parts by mass or more, and preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0158] In addition, conventionally known stearic acid can be used, such as products from NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Corporation, Chiba Fatty Acid Co., Ltd.

[0159] The above rubber composition may contain zinc oxide. In the above rubber composition, the zinc oxide content is preferably 1.0 part by mass or more, more preferably 2.0 parts by mass or more, and preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of the rubber component. Within this range, a better effect tends to be obtained.

[0160] In addition, conventionally known zinc oxides can be used, such as products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd.

[0161] The above-mentioned rubber composition for tires may contain sulfur. In the above-mentioned rubber composition for tires, the sulfur content is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, even more preferably 1.2 parts by mass or more, and preferably 3.5 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.5 parts by mass or less, per 100 parts by mass of the rubber component. When the content is within the above range, a better effect tends to be obtained.

[0162] Examples of sulfur commonly used in the rubber industry include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur. Commercially available products include those from Tsurumi Chemical Industries, Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Co., Ltd., Flexis Co., Ltd., Nippon Dry Distillation Co., Ltd., and Hosoi Chemical Industry Co., Ltd. These can be used individually or in combination of two or more types.

[0163] The above-mentioned rubber composition for tires may contain a vulcanization accelerator. In the above-mentioned rubber composition for tires, there are no particular restrictions on the content of the vulcanization accelerator, and it can be freely determined according to the desired vulcanization rate and crosslinking density. However, it is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the rubber component, and also preferably 15 parts by mass or less, and more preferably 10 parts by mass or less.

[0164] There are no particular restrictions on the type of vulcanization accelerator; commonly used ones can be used. Examples of vulcanization accelerators include benzothiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiadylsulfenamide; thiram-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-benzothiazolesulfenamide, Nt-butyl-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diortotrilguanidine, and orthotrilbiguanidine. Commercially available products from companies such as Sumitomo Chemical Co., Ltd. and Ouchi Shinko Chemical Co., Ltd. can be used. These may be used individually or in combination of two or more. Among these, sulfenamide, guanidine, and benzothiazole vulcanization accelerators are preferred.

[0165] In addition to the above-mentioned components, the above-mentioned rubber composition for tires may also appropriately contain compounding agents commonly used in the tire industry, such as mold release agents.

[0166] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from atmospheric carbon dioxide. As a method for obtaining the above formulations 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.

[0167] The above-mentioned rubber composition for tires can be manufactured, for example, by kneading each of the above components using a rubber mixing device such as an open roll or Banbury mixer, and then vulcanizing them.

[0168] Regarding the mixing conditions, in the base mixing step in which additives other than the crosslinking agent (vulcanizing agent) and vulcanization accelerator are mixed, the mixing temperature is preferably 100°C or higher, more preferably 120°C or higher, and also preferably 180°C or lower, more preferably 170°C or lower. In the finish mixing step in which the vulcanizing agent and vulcanization accelerator are mixed, the mixing temperature is preferably 80°C or higher, also preferably 120°C or lower, more preferably 110°C or lower. Furthermore, the composition mixed with the vulcanizing agent and vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is preferably 140°C or higher, more preferably 150°C or higher, also preferably 190°C or lower, more preferably 185°C or lower.

[0169] A tire having a tread made of the above-mentioned tire rubber composition is manufactured by conventional methods using the above-mentioned tire rubber composition. That is, a rubber composition, which may contain various additives as needed, can be extruded to match the shape of the tread at the unvulcanized stage, molded in conventional methods on a tire molding machine, bonded together with other tire components to form an unvulcanized tire, and then heated and pressurized in a vulcanizing machine to manufacture the tire.

[0170] The above-mentioned tires are not particularly limited and include, for example, pneumatic tires, solid tires, and airless tires. Among these, pneumatic tires are preferred.

[0171] The above tires can be used for passenger cars, large passenger cars, large SUVs, heavy-duty trucks and buses, light trucks, motorcycles, racing tires, winter tires (studless tires, snow tires, studded tires), all-season tires, run-flat tires, aircraft tires, mining tires, and more.

[0172] The tread of the above-described tire has a first land portion that is closest to the tire's equator and located on the outside of the vehicle relative to the tire's equator, and a second land portion located further out than the first land portion. In this specification, "outside of the vehicle" refers to the side that is further away from the center of the vehicle when the tire is mounted on the vehicle.

[0173] "The first land area closest to the equator on the outside of the vehicle, beyond the tire's equator" refers to a land area with a contact surface at least outside the vehicle's equator, in cases where there is no main groove on the equator. Examples of such land areas include land areas that straddle the equator or land areas that extend outside the vehicle with the equator as the groove edge. In cases where there is a main groove on the equator, it refers to the land area closest to the tire's equator on the outside of the vehicle, beyond the tire's equator.

[0174] "The second land area located outside the first land area" refers to the land area that is located outside the tire axis direction (outside the vehicle) of the first land area and has the largest width. If there are multiple such land areas, it refers to the land area closest to the outer contact edge of the vehicle.

[0175] "Land ratio L1 of the first land area closest to the equator outside the tire's equator and outside the vehicle" and "Land ratio L2 of the second land area located outside the first land area" refer to the land ratios of the "first land area closest to the equator outside the tire's equator" and the "second land area located outside the first land area," respectively, as defined above.

[0176] In this specification, "land area" refers to the portion of the area between two main grooves, or between one main groove and the tire's widthwise contact edge, that is intended to be in contact with the road surface.

[0177] In this specification, the main groove is defined as a groove that is continuous in the circumferential direction of the tire and has a cross-sectional area perpendicular to the circumferential direction of the tire of 10 mm². 2 This refers to the grooves described above. The shape of the grooves may be a straight line parallel to the circumferential direction of the tire, a wavy line, or a straight line that bends multiple times (zigzag).

[0178] Since the tire of the present invention has two or more land sections on the outside of the vehicle beyond the tire's equator, at least one main groove exists on the outside of the tire's equator.

[0179] Furthermore, since the dry grip performance during cornering, which is an effect of the present invention, is largely due to the contribution of the land portion on the outside of the vehicle rather than the tire's equator, any pattern may be formed on the inside of the tire's equator. It is preferable that the same relationship is satisfied for the land portion of the tire tread on the inside of the vehicle rather than the tire's equator. In other words, it is preferable that equation (1) is satisfied even when the inside and outside of the tire are swapped and mounted on the vehicle.

[0180] Figure 1 is an exploded view of the tread portion of one embodiment of the above tire. In Figure 1, the right side is the outer side in the tire axial direction (outside the vehicle), and the left side is the inner side in the tire axial direction (inside the vehicle).

[0181] The tread section is provided with at least two main grooves, and in this embodiment, as shown in Figure 1, three main grooves 2 are provided. The main grooves 2 include a main groove 2B that extends along the tire equator C, and main grooves 2A and 2C that extend on both outer sides of the main groove 2B. Each main groove 2 extends continuously in a straight line in the circumferential direction of the tire.

[0182] Each main groove 2 divides the tread's land portion 1 into four sections, 1A to 1D. In Figure 1, the land portion 1C located on the outer side of the vehicle in the main groove 2B extending along the tire equator C corresponds to the "first land portion that is closest to the equator while being on the outer side of the vehicle than the tire's equator." Also, the land portion 1D located on the outer side of the main groove 2C in the direction of the tire axis corresponds to the "second land portion located further out than the first land portion."

[0183] In this specification, if the tire is a pneumatic tire, the land ratio is calculated from the contact patch shape under normal rim, normal internal pressure, and normal load conditions. In the case of a non-pneumatic tire, it can be measured similarly without requiring normal internal pressure.

[0184] A "standard rim" refers to the rim specified for each tire within the standards system that the tire is based on. 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 Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" listed in the "STANDARDS MANUAL," and for TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "YEAR BOOK." Refer to JATMA, ETRTO, and TRA in that order, and if an applicable size is available at the time of reference, follow that standard. In the case of tires not specified in the standards, it refers to the rim with the smallest diameter and the narrowest rim width among rims that can be mounted on and can maintain internal pressure, i.e., rims that do not cause air leakage between the rim and tire.

[0185] "Regular internal pressure" refers to the air pressure specified for each tire by the aforementioned standards. For JATMA, it is the maximum air pressure; for ETRTO, it is "INFLATION PRESSURE"; and for TRA, it is the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES." Similar to the case of "regular rim," refer to JATMA, ETRTO, and TRA in that order and follow the respective standards. In the case of tires not specified in the standards, it refers to the regular internal pressure (but 250 kPa or higher) of another tire size (specified in the standards) that uses the aforementioned regular rim as the standard rim. If multiple regular internal pressures of 250 kPa or higher are listed, refer to the lowest value among them.

[0186] "Regular load" refers to the load specified for each tire in the standards system, including the standard on which the aforementioned tire is based, and represents the maximum mass that the tire is allowed to be loaded with. For JATMA, it refers to the maximum load capacity; for ETRTO, it refers to "LOAD CAPACITY"; and for TRA, it refers to the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". As with the "regular rim" and "regular internal pressure" mentioned above, refer to JATMA, ETRTO, and TRA in that order and follow their respective standards. For tires not specified in any standard, the regular load WL is determined by the following calculation. V={(Dt / 2)2-(Dt / 2-Ht)2}×π×Wt WL = 0.000011 × V + 175 WL: Regular load (kg) V: Virtual volume of the tire (mm²) 3 ) Dt: Tire outer diameter (mm) Ht: Tire section height (mm) Wt: Tire section width (mm)

[0187] The contact patch shape can be obtained by mounting the tire onto a standard rim, applying standard internal pressure, letting it stand at 25°C for 24 hours, then applying ink to the tire tread surface, applying standard load, pressing it onto cardboard (camber angle 0°), and transferring the shape to the paper. Therefore, the tire is rotated 72° in the circumferential direction, and the transfer is performed at 5 locations. In other words, the contact patch shape is obtained 5 times. At this time, for the 5 contact patch shapes, the parts that are interrupted by grooves in the contour are smoothly connected, and the resulting shape is considered the virtual contact surface.

[0188] The land ratio across the entire tread is calculated as: average area of ​​the five contact shapes (inked areas) transferred onto the cardboard / (average area of ​​the virtual contact surface of the five contact shapes) × 100 (%). The above L1 and L2 can be calculated in the same way as the land ratio for the entire tread by using the average area of ​​the ink portion corresponding to the land area of ​​each of the five contact shapes transferred to the cardboard, and the area of ​​the virtual contact surface of each corresponding land area.

[0189] In the above-mentioned tire, the land ratio of the entire tread is preferably 55% or more, more preferably 65% ​​or more, even more preferably 75% or more, and also preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less. When it is within the above range, the effect tends to be better obtained.

[0190] In the above-mentioned tire, the land ratio L1 of the first land portion closest to the equator on the outside of the vehicle, relative to the tire's equator, is preferably 65% ​​or more, more preferably 75% or more, even more preferably 85% or more, and also preferably 95% or less, more preferably 90% or less. Within this range, a better effect tends to be obtained.

[0191] In the above-described tire, the land ratio L2 of the second land portion, which is positioned outside the first land portion, is preferably 65% ​​or more, more preferably 75% or more, even more preferably 85% or more, and also preferably 95% or less, more preferably 90% or less. When it is within the above range, a better effect tends to be obtained.

[0192] For the above tires, L2 / L1 > 0.3. The value of (left side) is preferably 0.5 or higher, more preferably 0.8 or higher, even more preferably 1.0 or higher, and also preferably 2.0 or lower, more preferably 1.5 or lower, and even more preferably 1.1 or lower. When the value is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving wear resistance, the value is preferably 1.0 or higher, more preferably 1.07 or higher. Furthermore, from the viewpoint of improving ride comfort, the value is preferably 1.08 or lower, more preferably 1.0 or lower. In this relationship, L1 is the land ratio (in %) of the first land area closest to the equator, located outside the tire's equator, and L2 is the land ratio (in %) of the second land area located outside the first land area.

[0193] In the above tire, (L2 - L1 × 0.3) × total amount of styrene in the rubber component > 500. The value of (left side) is preferably 600 or more, more preferably 700 or more, even more preferably 800 or more, and also preferably 2000 or less, more preferably 1500 or less, and even more preferably 1000 or less. When it is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving grip performance, it is preferably 818.125 or higher, more preferably 1175.125 or higher, and even more preferably 1552.35 or higher. Furthermore, from the viewpoint of improving fuel efficiency, it is preferably 1552.35 or lower, more preferably 1175.125 or lower, and even more preferably 818.125 or lower. In this relationship, L1 is the land ratio (in %) of the first land portion closest to the equator on the outside of the vehicle, L2 is the land ratio (in %) of the second land portion located further out than the first land portion, and the total styrene content is the content in 100% by mass of the rubber component (in mass%).

[0194] In the above tire, it is preferable that (L2 - L1 × 0.3) × plasticizer content / 100 > 25. In this case, the value of (left side) is preferably 29 or more, more preferably 32 or more, even more preferably 35 or more, and also preferably 50 or less, more preferably 45 or less, and even more preferably 40 or less. The mechanism by which the above range is more effective is not clear, but it is presumed that the ability to follow the road surface is improved, and the vehicle can grip the road surface more firmly when turning. Therefore, it is presumed that the dry grip performance when turning is significantly improved. On the other hand, from the viewpoint of improving grip performance, the preferred value is 28.165 or higher, more preferably 29.75 or higher, even more preferably 32.725 or higher, even more preferably 34.715 or higher, even more preferably 35.7 or higher, and even more preferably 41.65 or higher. Furthermore, from the viewpoint of improving wear resistance, the preferred value is 41.65 or lower, more preferably 35.7 or lower, even more preferably 34.715 or lower, even more preferably 32.725 or lower, even more preferably 29.75 or lower, and even more preferably 28.165 or lower. In this relationship, L1 is the land ratio (in %) of the first land portion closest to the equator on the outside of the vehicle, L2 is the land ratio (in %) of the second land portion located further out than the first land portion, and the plasticizer content is the content per 100 parts by mass of rubber component (in parts by mass).

[0195] In the above-mentioned tire, it is preferable that the land ratio × silica CTAB specific surface area / 100 in the entire tread is > 150. In this case, the value of (left side) is preferably 160 or more, more preferably 170 or more, even more preferably 180 or more, and also preferably 250 or less, more preferably 220 or less, and even more preferably 200 or less. When it is within the above range, a better effect tends to be obtained. On the other hand, from the viewpoint of improving wear resistance, the value is preferably 127.5 or higher, more preferably 176.475 or higher, even more preferably 183.75 or higher, and even more preferably 191.1 or higher. Furthermore, from the viewpoint of improving fuel efficiency, the value is preferably 191.1 or lower, more preferably 183.75 or lower, even more preferably 176.475 or lower, even more preferably 127.5 or lower, even more preferably below, and even more preferably below. In this relationship, the unit of the land ratio for the entire tread is %, and the unit of the CTAB specific surface area of ​​silica is m 2 It is / g.

[0196] In the above-mentioned tire, it is preferable that the content of the ionic coupling agent is >350 (L2-L1 × 0.3). In this case, the value of (left side) is preferably 370 or more, more preferably 390 or more, even more preferably 410 or more, and also preferably 500 or less, more preferably 460 or less, and even more preferably 430 or less. When it is within the above range, a better effect tends to be obtained. In this relationship, L1 is the land ratio (in %) of the first land portion closest to the equator on the outside of the vehicle, L2 is the land ratio (in %) of the second land portion located further out than the first land portion, and the content of the ionic coupling agent is the content per 100 parts by mass of the rubber component (in parts by mass). [Examples]

[0197] The following examples (implementations) are considered preferable for implementation, but the scope of the present invention is not limited to these examples.

[0198] The various chemicals used in the examples and comparative examples are described below. NR:TSR20 SBR1: HPR850 manufactured by JSR Corporation (Tg -25℃, styrene content 27.5% by mass, vinyl content 59% by mass) SBR2: HPR830E manufactured by JSR Corporation (Tg -23°C, styrene content 39.5% by mass, vinyl content 38.5% by mass, containing 10 parts by mass of oil per 100 parts by mass of rubber solids) SBR3: HPR840 manufactured by JSR Corporation (Tg -60°C, styrene content 10% by mass, vinyl content 42% by mass) BR: BR150B manufactured by Ube Industries, Ltd. (cis content 95% by mass or more) Carbon black: N220 (CTAB specific surface area 111m 2 / g) Silica 1: ULTRASIL VN3 manufactured by Evonik Industries AG (CTAB specific surface area 170m 2 / g) Silica 2: Zeosil Premium SW manufactured by Solvay (CTAB specific surface area 245m 2 / g) Silica 3: ULTRASIL 9100GR manufactured by Evonik Industries AG (CTAB specific surface area 200m 2 / g) Magnesium sulfate: MN-00 manufactured by Maki Kasei Kogyo Co., Ltd. (anhydrous magnesium sulfate, median particle size (median diameter) 75μm) Silane coupling agent 1: Si266 manufactured by Evonik Industries AG (bis(3-triethoxysilylpropyl) disulfide) Silane coupling agent 2: NXT manufactured by Momentive (3-octanoylthiopropyltriethoxysilane) Ionic bonding coupling agent 1: X-12-1126 of Shin-Etsu Chemical Co., Ltd. (quaternary ammonium salt, hydrolyzate of the compound represented by formula (1), compound represented by formula (1-1)) Ionic bonding coupling agent 2: KBM-9418-40 of Shin-Etsu Chemical Co., Ltd. (quaternary ammonium salt, compound represented by formula (1)) Liquid rubber: LIR-410 manufactured by Kuraray Co., Ltd. (maleic acid-modified liquid polyisoprene, Mw 30000) Oil 1: A / O Mix manufactured by Sankyo Yuka Kogyo Co., Ltd. Oil 2: Nisshin Soybean White Press Oil manufactured by Nisshin Oillio Group Co., Ltd. Resin 1: Opera PR-383 (hydrogenated DCPD-C9 resin) manufactured by Exxon Mobil Resin 2: Sylvatraxx 4401 (copolymer of α-methylstyrene and styrene) manufactured by Arizona Chemical Resin 3: YS Resin TO125 (terpene styrene resin (copolymer of terpene compound and styrene)) manufactured by Yasuhara Chemical Co., Ltd. Wax: Oz Ace 0355 manufactured by Nippon Seiro Co., Ltd. Antioxidant 1: No Crack 6C (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) (6PPD) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Antioxidant 2: Antage RD (polymer of 2,2,4-trimethyl-1,2-dihydroquinoline) manufactured by Kawaguchi Chemical Industry Co., Ltd. Stearic acid: Stearic acid "Tsubaki" manufactured by NOF Corporation Zinc oxide: Zinc white No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: HK-200-5 (powder sulfur containing 5% oil) manufactured by Hosoi Chemical Industry Co., Ltd. Fatty acid derivative 1: WB16 (mixture of fatty acid metal salt (calcium fatty acid, constituent fatty acid: saturated fatty acid with 14 to 20 carbon atoms) and fatty acid amide) manufactured by Struktol Fatty acid derivative 2: Activator 73A (mixture of zinc salts of aliphatic carboxylic acids and zinc salts of aromatic carboxylic acids) manufactured by Struktol Vulcanization accelerator 1: Nocceler CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Nocceler D (diphenylguanidine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0199] <Examples and Comparative Examples> (Base kneading process) According to the formulation shown in Tables 1 and 2, the materials are put into a Banbury mixer and kneaded. After kneading at a rubber temperature of 160°C for 2 minutes, it is discharged. Only the mixture (sheet rubber) obtained by discharge is put into the Banbury mixer and further kneaded (discharge temperature 160°C). (Finishing kneading process) The above mixture, sulfur, and vulcanization accelerator are placed in a Banbury mixer and kneaded to obtain an unvulcanized rubber composition. Kneading is stopped when the rubber temperature reaches 100°C. (Vulcanization process) An unvulcanized rubber composition is molded into the shape of a cap tread, bonded together with other tire components to form an unvulcanized tire, and then press-vulcanized at 150°C for 12 minutes to produce a test tire.

[0200] The above test tires were evaluated as follows. The results are shown in Tables 1 and 2. In the evaluation method described below, the evaluation criteria for calculating the index are as follows: Table 1: Comparative Example 1 Table 2: Comparative Example 4

[0201] In the table, the rubber content in the oil-applied rubber is listed in the "Rubber" column, and the oil content in the oil-applied rubber is added to the "Oil 1" column.

[0202] Furthermore, the tire sizes in Tables 1 and 2 are as follows: Table 1:185 / 65R14 Table 2:215 / 65R14

[0203] Furthermore, the land ratio, L1, and L2 for the entire tread in Tables 1 and 2 are as follows: Table 1: Land ratio across the entire tread: 75%, L1: 85%, L2: 85%, L2 / L1: 1.0 Table 2: Land ratio across the entire tread: 78%, L1: 85%, L2: 91%, L2 / L1: 1.07

[0204] (Dry grip performance during cornering) Vehicles equipped with each test tire on all wheels are used to perform cornering maneuvers on a dry test track. Drivers subjectively evaluate the grip performance on a 5-point scale from 1 to 5. The total scores from 20 drivers are calculated and expressed as an index, with a baseline of 100. A higher index indicates superior dry grip performance during cornering.

[0205]

Table 1

[0206]

Table 2

[0207] The present invention (1) is a tire provided with a tread, wherein the tread is composed of a rubber composition for a tire containing a rubber component including styrene-butadiene rubber and an ionic bonding coupling agent, and has a first land portion closest to the equator on the outer side of the vehicle with respect to the equator of the tire and a second land portion disposed outside the first land portion, a tire satisfying the following (1) to (3). (1) The styrene content of the styrene-butadiene rubber is more than 20% by mass (2) When the land ratio of the first land portion is L1 and the land ratio of the second land portion is L2, L2 / L1 > 0.3 (3) (L2 - L1 × 0.3) × the total styrene amount in the rubber component > 500

[0208] The present invention (2) is the tire according to the present invention (1), wherein the rubber component contains isoprene rubber.

[0209] The present invention (3) is the tire according to the present invention (1) or (2), wherein the rubber component contains butadiene rubber.

[0210] The present invention (4) is a tire in any combination with any one of the present inventions (1) to (3), containing 100 parts by mass or more of silica with respect to 100 parts by mass of the rubber component.

[0211] The present invention (5) is a tire in any combination with any one of the present inventions (1) to (4), containing silica having a CTAB specific surface area of 220 m 2 / g or more.

[0212] The present invention (6) is a tire comprising any combination of the present inventions (1) to (5) and containing 50 parts by mass or more of a plasticizer per 100 parts by mass of the rubber component.

[0213] The present invention (7) is a tire that contains a resin, wherein the resin is at least one selected from the group consisting of dicyclopentadiene resins, aromatic vinyl resins, and terpene resins, and is any combination of the present invention (1) to (6).

[0214] The present invention (8) is a tire containing liquid rubber in any combination of any of the present inventions (1) to (7).

[0215] The present invention (9) is a tire containing a mercapto-silane coupling agent in any combination of the present inventions (1) to (8).

[0216] The present invention (10) is a tire in any combination of the present invention (1) to (9), wherein the ionic coupling agent is a quaternary ammonium salt.

[0217] The present invention (11) is a tire in any combination with any of the present inventions (1) to (10) such that the total amount of styrene in the rubber component × (plasticizer content + silica content) / 100 > 50.

[0218] Invention (12) is a tire in any combination with any of Inventions (1) to (11) such that (L2-L1×0.3)×plasticizer content / 100>25.

[0219] The present invention (13) is a tire in any combination of the land ratio × silica CTAB specific surface area / 100 > 150 in the entire tread, and any combination of the present invention (1) to (12).

[0220] The present invention (14) is a tire in any combination of any of the present inventions (1) to (13) such that (L2-L1×0.3) × the content of the ionic coupling agent > 350.

[0221] The present invention (15) is a tire in any combination of any of the present inventions (1) to (14) wherein the silica content / total styrene content in the rubber component > 5.

[0222] The present invention (16) is a tire in any combination of the present invention (1) to (15), wherein the styrene content of the styrene-butadiene rubber is 25% by mass or more and 40% by mass or less.

[0223] Invention (17) is a tire in any combination with any of Inventions (1) to (16) such that 0.8 ≤ L2 / L1 ≤ 1.5.

[0224] The present invention (18) is a tire in any combination with any of the present inventions (1) to (17) such that 700 ≤ (L2 - L1 × 0.3) × total amount of styrene in the rubber component ≤ 1500. [Explanation of Symbols]

[0225] 1 land area 2 Main groove C Tire Equator

Claims

1. A tire having a tread, The tread is composed of a tire rubber composition containing a rubber component including styrene-butadiene rubber and an ionic coupling agent, and has a first land portion closest to the equator on the outside of the vehicle relative to the equator of the tire, and a second land portion located further out than the first land portion. A tire that satisfies the following conditions (1) to (3). (1) The styrene content of the styrene-butadiene rubber exceeds 20% by mass. (2) When the land ratio of the first land area is L1 and the land ratio of the second land area is L2, L2 / L1 > 0.3 (3) (L2 - L1 × 0.3) × Total amount of styrene in the rubber component > 500

2. The tire according to claim 1, wherein the rubber component comprises isoprene-based rubber.

3. The tire according to claim 1 or 2, wherein the rubber component comprises butadiene rubber.

4. The tire according to claim 1 or 2, wherein the tire contains 100 parts by mass or more of silica per 100 parts by mass of the rubber component.

5. CTAB specific surface area is 220 m² ２ A tire according to claim 1 or 2, containing silica of 1g or more.

6. The tire according to claim 1 or 2, wherein the tire contains 50 parts by mass or more of a plasticizer per 100 parts by mass of the rubber component.

7. The tire according to claim 1 or 2, which contains a resin, wherein the resin is at least one selected from the group consisting of dicyclopentadiene resins, aromatic vinyl resins, and terpene resins.

8. A tire according to claim 1 or 2, containing liquid rubber.

9. A tire according to claim 1 or 2, comprising a mercapto-silane coupling agent.

10. The tire according to claim 1 or 2, wherein the ionic coupling agent is a quaternary ammonium salt.

11. The tire according to claim 1 or 2, wherein the total amount of styrene in the rubber component × (plasticizer content + silica content) / 100 > 50.

12. The tire according to claim 1 or 2, wherein (L2 - L1 × 0.3) × plasticizer content / 100 > 25.

13. The tire according to claim 1 or 2, wherein the land ratio over the entire tread × silica CTAB specific surface area / 100 > 150.

14. The tire according to claim 1 or 2, wherein (L2 - L1 × 0.3) × the content of the ionic coupling agent > 350.

15. The tire according to claim 1 or 2, wherein the silica content / total styrene content in the rubber component > 5.

16. The tire according to claim 1 or 2, wherein the styrene content of the styrene-butadiene rubber is 25% by mass or more and 40% by mass or less.

17. The tire according to claim 1 or 2, wherein 0.8 ≤ L2 / L1 ≤ 1.

5.

18. The tire according to claim 1 or 2, wherein 700 ≤ (L2 - L1 × 0.3) × total amount of styrene in the rubber component ≤ 1500.

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