tire

Abstract

We provide tires that offer excellent fuel efficiency for city driving. [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 a carboxylic acid-modified diene rubber, a filler containing silica, and an ionic coupling agent, and the tire has a first land portion closest to the equator on the outside of the vehicle relative to the equator and a second land portion located further out than the first land portion, and satisfies the following (1) to (3). (1) The amount of polymer (PC), acetone extract (AE), carbon black (BC), and ash (Ash) in the rubber composition is (PC + AE) / (BC + Ash) > 1 (2) When the width of the first land area is W1 and the width of the second land area is W2, W1 / W2 > 0.3 (3)(W1-W2×0.3)×(PC+AE-BC-Ash)>100

Description

[Technical Field]

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

[0002] Tires used in automobiles are required to have low fuel consumption performance, and various rubber compositions 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. 2000-344955 [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 fuel efficiency performance when driving in urban areas. [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 a carboxylic acid-modified diene rubber, a filler containing silica, 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's equator, and satisfies the following (1) to (3). (1) The amount of polymer (PC), acetone extract (AE), carbon black (BC), and ash (Ash) in the rubber composition is (PC + AE) / (BC + Ash) > 1 (2) When the width of the first land area is W1 and the width of the second land area is W2, W1 / W2 > 0.3 (3)(W1-W2×0.3)×(PC+AE-BC-Ash)>100 [Effects of the Invention]

[0006] The present invention provides a tire having a tread, wherein the tread is composed of a rubber composition containing a rubber component including a carboxylic acid-modified diene rubber, a filler containing silica, 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 above (1) to (3), thus providing a tire with excellent fuel efficiency performance during city driving. [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, wherein the tread is composed of a tire rubber composition containing a rubber component including a carboxylic acid-modified diene rubber, a filler containing silica, 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 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. By increasing the width of the land portion on the equatorial side, the rigidity of the tread is increased, which suppresses deformation of the rubber blocks. Furthermore, by satisfying the above relation (1), energy loss due to the interaction between the filler and polymer can be reduced. In other words, it suppresses the deformation of the block and also reduces the energy loss caused by the deformation of the block. Based on the above, it is presumed that fuel efficiency during city driving will be significantly improved. Because the above tires excel in fuel efficiency during city driving, they are particularly effective in situations where vehicles frequently travel in urban areas and make many turns, such as taxis and route buses.

[0010] In the above rubber composition, the polymer content (PC) is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% 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, the effect tends to be better obtained. That's good too.

[0011] In the above rubber composition, the amount of acetone extract (AE) is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and also preferably 45% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. When the amount is within the above range, a better effect tends to be obtained.

[0012] In the above rubber composition, the amount of carbon black (BC) is preferably 0.5% by mass or more, more preferably 1.5% by mass or more, even more preferably 2.5% by mass or more, and also preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. When the amount is within the above range, the effect tends to be better obtained.

[0013] In the above rubber composition, the ash content is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and also preferably 55% by mass or less, more preferably 45% by mass or less, and even more preferably 35% by mass or less. When the ash content is within the above range, the effect tends to be better.

[0014] PC, AE, BC, and Ash are measured using the following methods. AE is measured for the above rubber composition (sample) using the acetone extraction amount measurement method in accordance with JIS K 6229:2015 (unit: mass %) of the above rubber composition (sample). PC is calculated from the amount of weight (mass) lost when organic matter in the sample remaining after the acetone extraction is thermally decomposed and vaporized by heating in nitrogen (raising the temperature from room temperature to 750°C), in accordance with JIS K6226-1:2003 (unit: mass %) of the above rubber composition (sample). BC is calculated from the amount of weight (mass) lost when the sample, after the above thermal decomposition and vaporization, is oxidized and burned by heating in air (unit: mass %) of the above rubber composition (sample). Ash is calculated from the mass of the components (ash) that do not burn in the above-mentioned oxidative combustion (unit: mass %) of the above-mentioned rubber composition (sample). Based on the above definitions, the sum of AE, PC, BC, and Ash is 100% by mass.

[0015] Methods known to those skilled in the art can be used to adjust AE, PC, BC, and Ash. For example, AE tends to increase as the amount of plasticizers such as oil in the rubber composition increases. PC tends to increase as the amount of rubber components in the rubber composition increases. BC tends to increase as the amount of carbon black in the rubber composition increases. Ash tends to increase as the amount of components that do not burn by oxidative combustion, such as silica, in the rubber composition increases.

[0016] In the above rubber composition, (PC+AE) / (BC+Ash)>1. In this case, the value of (left side) is preferably 1.5 or higher, more preferably 1.8 or higher, even more preferably 2.0 or higher, and also preferably 4.5 or lower, more preferably 3.5 or lower, and even more preferably 2.5 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 machinability, the preferred value is 1.42 or higher, more preferably 1.43 or higher, even more preferably 1.46 or higher, even more preferably 1.51 or higher, even more preferably 1.55 or higher, even more preferably 1.81 or higher, and even more preferably 2.02 or higher. Furthermore, from the viewpoint of improving wear resistance, the preferred value is 2.03 or lower, more preferably 1.82 or lower, even more preferably 1.56 or lower, even more preferably 1.52 or lower, even more preferably 1.47 or lower, even more preferably 1.44 or lower, and even more preferably 1.43 or lower.

[0017] The above rubber composition contains rubber components. In this specification, the "rubber component" is a component that contributes to crosslinking, and may be either a solid rubber under the conditions of 1 atmosphere and 25°C (solid rubber) or a liquid rubber under the conditions of 1 atmosphere and 25°C (liquid rubber). In particular, it is preferable to include liquid rubber. In this specification, the rubber component is a polymer with a weight-average molecular weight (Mw) of 10,000 or more.

[0018] The weight-average molecular weight of the rubber component is preferably 30,000 or more, more preferably 100,000 or more, even more preferably 150,000 or more, and particularly preferably 270,000 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.

[0019] 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.

[0020] The total styrene content in the rubber component is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 18% by mass or more, and also preferably 35% by mass or less, more preferably 25% by mass or less, and even more preferably 20% 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 12.65% by mass or more, more preferably 12.925% by mass or more, even more preferably 18.17% by mass or more, and even more preferably 18.565% by mass or more. Furthermore, from the viewpoint of improving processability, it is preferably 18.565% by mass or less, more preferably 18.17% by mass or less, even more preferably 12.925% by mass or less, and even more preferably 12.65% by mass or less.

[0021] 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 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).

[0022] 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.

[0023] The above rubber components may include 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.

[0024] The above rubber component may include 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. A cis content of 95% by mass or more is more preferable. The cis content can be measured by infrared absorption spectroscopy.

[0025] 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 using the formula {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)).

[0026] Hydrogenated butadiene polymer (hydrogenated BR) can also be used as the above-mentioned BR.

[0027] For example, products from companies such as Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation can be used as BRs.

[0028] The above rubber component may also 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.

[0029] 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 may be -70°C or higher. When it is within the above range, the effect tends to be better obtained.

[0030] 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)).

[0031] In the above rubber composition, the styrene content of SBR is preferably 15% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, and also preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% 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 processability, the amount is preferably 39.5% by mass or less, and more preferably 27.5% by mass or less.

[0032] 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)).

[0033] The vinyl content of SBR is preferably 15% by mass or more, more preferably 25% by mass or more, even more preferably 35% by mass or more, and also preferably 65% ​​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 grip performance, it is preferably 38.5% by mass or more, and more preferably 59% by mass or more.

[0034] 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%])}.

[0035] As mentioned above, hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used as SBR.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Whether the raw material of the polymer is derived from biomass can be determined by pMC (percent Modern Carbon) measured in accordance with ASTM D6866-10.

[0043] pMC is the ratio of the 14 C concentration of the sample to the 14 C concentration of the modern standard reference, and is a value used as an index indicating the biomass ratio of a compound. The significance of this value is described below.

[0044] In one mole (6.02×10 23 atoms) of carbon atoms, there are approximately 6.02×10 11 atoms of 14 C, which is about one trillionth of the normal 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, in fossil fuels such as coal, oil, and natural gas, which are considered to have passed more than 226,000 years after carbon dioxide in the atmosphere was taken up and immobilized by plants, etc., all of the 14 C elements contained in them at the time of immobilization have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas do not contain 14 C elements at all. Therefore, chemical substances produced from these fossil fuels as raw materials also do not contain 14 C elements at all.

[0045] On the other hand, 14 C is constantly generated by nuclear reactions of cosmic rays in the atmosphere, and the balance between the decrease due to radioactive decay results in a constant amount of 14 C in the earth's atmospheric environment. Therefore, the 14 C concentration of substances derived from biomass resources circulating in the current environment is about 1×10 -12The values ​​are approximately in the range of mol%. Therefore, the difference between these values ​​can be used to calculate the biomass ratio of a particular compound.

[0046] this 14 C is typically measured as follows: Using accelerator mass spectrometry based on a tandem accelerator, 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 Perform measurement C). 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 standard value is obtained by correcting C to a constant value and applying decay correction from 1950 AD to the measurement date. 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.

[0047] 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 approximately 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0% as mentioned above.

[0048] 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.

[0049] When the above rubber component includes isoprene-based rubber, the isoprene-based rubber content 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 25% 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 wear resistance, the amount is preferably 28% by mass or more, and more preferably 38% by mass or more.

[0050] When the above rubber component contains BR, the BR content in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and also preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. When it is within the above range, the effect tends to be better obtained. On the other hand, from the viewpoint of improving handling stability during high-speed driving, it is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0051] When the above rubber component contains SBR, the SBR content in 100% by mass of the rubber component is preferably 25% by mass or more, more preferably 35% by mass or more, even more preferably 45% by mass or more, and also preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the content is within the above range, the effect tends to be better obtained.

[0052] The above tire rubber composition may contain other rubber components in addition to isoprene-based rubber, BR, and SBR. 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.

[0053] The above rubber components include carboxylic acid-modified diene rubber. In this specification, the carboxylic acid-modified diene rubber may be in a solid state (solid rubber) or a liquid state (liquid rubber) under conditions of 1 atmosphere and 25°C. In "carboxylic acid-modified diene rubber," "carboxylic acid modification" refers to the inclusion of a functional group derived from a carboxylic acid in the molecule of the diene rubber. Examples of carboxylic acids include maleic acid, fumaric acid, itaconic acid, and (meth)acrylic acid, with maleic acid being preferred. There may be one carboxylic acid or two or more. Furthermore, the carboxylic acid-modified diene rubber mentioned above is a polymer with an Mw of 10,000 or more, and corresponds to the rubber component described above.

[0054] When the above-mentioned carboxylic acid-modified diene rubber is a solid rubber under conditions of 1 atmosphere and 25°C, examples of diene rubbers that constitute the skeleton of the carboxylic acid-modified diene rubber include the above-mentioned isoprene rubber, BR, SBR, SIBR, EPDM, CR, NBR, etc. Among these, BR and SBR are preferred, and SBR is more preferred.

[0055] When the carboxylic acid-modified diene rubber is a solid rubber under conditions of 1 atmosphere and 25°C, the content of the carboxylic acid-modified diene rubber in 100% by mass of the rubber component in the above tire rubber composition is preferably 3% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and also preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0056] On the other hand, when the carboxylic acid-modified diene rubber is a liquid rubber under conditions of 1 atmosphere and 25°C, examples of liquid diene rubbers (liquid rubbers) that constitute the skeleton of the carboxylic acid-modified diene rubber include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), liquid styrene-butadiene-styrene block copolymer (liquid SBS block polymer), and liquid styrene-isoprene-styrene block copolymer (liquid SIS block polymer). Among these, liquid IR is preferred. In particular, the modified liquid rubber is preferably a modified diene-based rubber that is in a liquid state under the conditions of 1 atmosphere and 25°C.

[0057] Examples of liquid diene-based rubbers that can be used include products from companies such as Sartomer and Kuraray.

[0058] When the carboxylic acid-modified diene rubber is in a liquid state under conditions of 1 atmosphere and 25°C, the content of the carboxylic acid-modified diene rubber in 100% by mass of the rubber component in the above tire rubber composition is preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 6% by mass or more, and also preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. When the content is within the above range, a better effect tends to be obtained.

[0059] The above rubber composition contains silica as a filler. 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.

[0060] 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.

[0061] The silica recycled from silica-containing products can be, for example, silica recovered from products containing silica such as semiconductors and other electronic components, tires, desiccants, and diatomaceous earth and other filter materials. The recovery method is not particularly limited and can include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from semiconductors and other electronic components or tires is preferred.

[0062] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (see Japanese Patent Publication No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol.6, pp.216-222, etc.).

[0063] Amorphous silica extracted from rice husks can be commercially available from companies such as Wilmar.

[0064] The CTAB specific surface area of ​​silica (cetyltrimethylammonium bromide adsorption specific surface area, CTAB) is preferably 100 m². 2 / g or more, more preferably 140m 2 / g or more, more preferably 170m 2 / g or more, more preferably 200m 2 It is 1 / g or more. Furthermore, the upper limit of the CTAB of silica is not particularly limited, but preferably 350m 2 Less than / g, more preferably 300m 2 / g or less, more preferably 260m 2 It is less than / g. Although the mechanism by which the above range is more effective is not clear, it is presumed that the polymer chains are more firmly bound to silica, suppressing the movement of the polymer chains and improving fuel efficiency during city driving. In this specification, the CTAB specific surface area of ​​silica is the value measured in accordance with JIS K6217-3.

[0065] 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.

[0066] 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.

[0067] The above rubber composition may contain fillers other than silica. Other fillers are not particularly limited and materials known in the rubber field can be used, such as inorganic fillers such as carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica, as well as water-soluble fillers, biochar, and poorly dispersible fillers. These may be used alone or in combination of two or more. Among these, water-soluble fillers are preferred.

[0068] 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.

[0069] 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. Furthermore, the above CTAB is 200m 2 Preferably less than / g, 180m 2 More preferably less than / g, 160m 2 A value of less than / g is even more preferable. Within the above range, there is a tendency to obtain better effects. The CTAB specific surface area of ​​carbon black is a value measured in accordance with JIS K6217-3.

[0070] The median particle size (median diameter, D50) of the water-soluble filler is preferably 0.4 μm or larger, more preferably 0.6 μm or larger, and even more preferably 1.0 μm or larger. The upper limit is preferably 200 μm or smaller, more preferably 150 μm or smaller, even more preferably 50 μm or smaller, and particularly preferably 20 μm or smaller. Within the above range, better effects tend to be obtained. In this specification, the median particle size of a water-soluble filler can be measured by laser diffraction, and refers to the particle size of the 50% integrated value in the mass-based particle size distribution curve obtained by laser diffraction scattering. The median particle size of water-soluble fillers is measured by the following method. [Measurement of median particle size (median diameter) of water-soluble fillers] The measurement will be performed using the SALD-2000J model manufactured by Shimadzu Corporation, employing the laser diffraction method. The operating procedure is as follows: <Measurement Procedure> A water-soluble filler is dispersed at room temperature in a mixed solution of a dispersion solvent (toluene) and a dispersant (10% by mass of di-2-ethylhexyl sodium sulfosuccinate / toluene solution). The resulting dispersion is stirred for 5 minutes while being irradiated with ultrasound to obtain a test solution. The test solution is transferred to a batch cell and measured after 1 minute. (Refractive index: 1.70-0.20i)

[0071] Examples of water-soluble fillers include water-soluble inorganic salts and water-soluble organic substances. These may be used individually or in combination of two or more.

[0072] Examples of water-soluble inorganic salts include metal sulfates such as magnesium sulfate, sodium sulfate, and potassium sulfate; metal chlorides such as potassium chloride, sodium chloride, calcium chloride, and magnesium chloride; metal hydroxides such as potassium hydroxide and sodium hydroxide; carbonates such as potassium carbonate, sodium carbonate, and calcium bicarbonate; and phosphates such as sodium hydrogen phosphate and sodium dihydrogen phosphate.

[0073] Examples of water-soluble organic substances include lignin derivatives and sugars. Suitable lignin derivatives include lignin sulfonic acid and lignin sulfonate salts. The lignin derivative may be obtained by either the sulfite pulp method or the kraft pulp method.

[0074] Examples of ligninsulfonates include alkali metal salts, alkaline earth metal salts, ammonium salts, and alcoholamine salts of ligninsulfonic acid. Among these, alkali metal salts (potassium salts, sodium salts, etc.) and alkaline earth metal salts (calcium salts, magnesium salts, lithium salts, barium salts, etc.) of ligninsulfonic acid are preferred.

[0075] The lignin derivative preferably has a sulfonation degree of 1.5 to 8.0 / OCH3. In this case, the lignin derivative includes ligninsulfonic acid and / or ligninsulfonate salts in which at least a portion of lignin and / or its decomposition products are substituted with sulfon groups (sulfonated groups), and the sulfon groups of the ligninsulfonic acid may be in an unionized state, or the hydrogen of the sulfon group may be substituted with an ion such as a metal ion. The sulfonation degree is more preferably 3.0 to 6.0 / OCH3. The effect tends to be more favorably obtained by keeping it within the above range.

[0076] The degree of sulfonation of lignin derivative particles (the lignin derivatives that constitute the particles) is the rate of introduction of sulfo groups and can be calculated using the following formula. Sulfonation degree ( / OCH3) = S (moles) in the sulfone group in the lignin derivative / methoxyl group (moles) in the lignin derivative

[0077] Sugars have no particular restrictions on the number of carbon atoms they consist of and can be monosaccharides, oligosaccharides, or polysaccharides. Examples of monosaccharides include trisaccharides such as aldotrioose and ketotriose; tetrasaccharides such as erythrose and threose; pentoses such as xylose and ribose; hexoses such as mannose, allose, altrose, and glucose; and heptasaccharides such as sedoheptulose. Examples of oligosaccharides include disaccharides such as sucrose and lactose; trisaccharides such as raffinose and melegitose; tetrasaccharides such as acarbose and stachyose; and oligosaccharides such as xylooligosaccharides and cellooligosaccharides. Examples of polysaccharides include glycogen, starch (amylose, amylopectin), cellulose, hemicellulose, dextrin, and glucan.

[0078] Among water-soluble fillers, water-soluble inorganic salts are preferred, metal sulfates are more preferred, and magnesium sulfate is even more preferred. Among magnesium sulfates, anhydrous magnesium sulfate, magnesium sulfate dihydrate, and magnesium sulfate trihydrate are preferred, and anhydrous magnesium sulfate is more preferred.

[0079] It is presumed that if the above rubber composition contains a water-soluble filler, its fuel efficiency during city driving tends to improve.

[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 55 parts by mass or more, more preferably 65 parts by mass or more, even more preferably 75 parts by mass or more, and preferably 140 parts by mass or less, more preferably 120 parts by mass or less, and even more preferably 100 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 80 parts by mass or more, more preferably 89 parts by mass or more, even more preferably 117 parts by mass or more, and even more preferably 135 parts by mass or more. Furthermore, from the viewpoint of improving processability, the amount is preferably 135 parts by mass or less, more preferably 117 parts by mass or less, even more preferably 89 parts by mass or less, and even more preferably 80 parts by mass or less.

[0085] In the above-mentioned rubber composition for tires, the silica content is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, and even more preferably 100 parts by mass or more, and also preferably 150 parts by mass or less, more preferably 130 parts by mass or less, and even more preferably 110 parts by mass or less. The mechanism by which the above range yields greater effectiveness is not clear, but it is presumed that the polymer chains are more firmly bound to the silica, thereby suppressing the movement of the polymer chains and improving fuel efficiency during city driving. On the other hand, from the viewpoint of improving wear resistance, the amount is preferably 75 parts by mass or more, more preferably 103 parts by mass or more, and even more preferably 121 parts by mass or more. Furthermore, from the viewpoint of improving processability, the amount is preferably 121 parts by mass or less, more preferably 103 parts by mass or less, and even more preferably 75 parts by mass or less.

[0086] When the above tire rubber composition contains carbon black, the carbon black content is preferably 1.5 parts by mass or more, more preferably 3.0 parts by mass or more, even more preferably 4.5 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.

[0087] When the above tire rubber composition contains a water-soluble filler, the water-soluble filler content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 9 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 this range, a better effect tends to be obtained.

[0088] 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.

[0089] 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.

[0090] 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).

[0091] [ka]

[0092] 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 34 At 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.

[0093] 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).

[0094] 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.

[0095] 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 have a cyclic structure. 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.

[0096] R in equation (1) 31 and R 32 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.

[0097] 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.

[0098] R in equation (1) 34 Preferably, at least one of the organic groups has a quaternary ammonium group. Examples of the group having a quaternary ammonium group include groups represented by the following formulae.

Chemical formula

[0099] In the formula, R 35 ~R 37 each independently represents a monovalent organic group. R 38 each independently represents a divalent organic group. Y - represents an anion. k represents an integer.

[0100] Examples of the monovalent organic group of R 35 ~R 37 include monovalent hydrocarbon groups, and examples of the monovalent hydrocarbon group include an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and the like. R 35 ~R 37 preferably has 1 to 12 carbon atoms, more preferably 1 to 7 carbon atoms, still more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. R 35 ~R 37 The monovalent organic group is particularly preferably a methyl group or an ethyl group.

[0101] Examples of the divalent organic group of R 38 include divalent hydrocarbon groups, and examples of the divalent hydrocarbon group include an alkylene group having 1 to 12 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, and the like. R 38 preferably has 1 to 12 carbon atoms, more preferably 1 to 7 carbon atoms, still more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. R 38 The divalent organic group is particularly preferably a methylene group or an ethylene group.

[0102] k is preferably 0 to 5, more preferably 0 to 3, still more preferably 0 to 1, and particularly preferably 0.

[0103] Y -is not particularly limited, and examples thereof include 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, dodecylbenzenesulfonate ions, ethanesulfonate ions, etc.); sulfonimide ions (bis(trifluoromethanesulfonate)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, and the like.

[0104] Among the compound represented by the above formula (1), the hydrolyzate of the compound represented by the above formula (1), and the hydrolysis condensate of the compound represented by the above formula (1), from the viewpoint of obtaining better effects, the compound represented by the following formula (1-1) is desirable.

[0105]

Chemical formula

[0106] 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.

[0107] In equation (1-1), R 35 ~R 37 , R 38 , Y - The preferred example of k is the same as described above.

[0108] The effect is better obtained when the ionic coupling agent has a salt structure such as a quaternary ammonium salt, such as the compound represented by formula (1-1). The compound represented by formula (1) preferably has a quaternary ammonium salt structure. The ionic coupling agent is more preferably a quaternary ammonium salt.

[0109] The ionic coupling agent mentioned above can be a commercially available product such as X-12-1126 or KBM-9418-40 manufactured by Shin-Etsu Chemical Co., Ltd.

[0110] In the above-mentioned rubber composition for tires, the total content of the ionic coupling agent is preferably 3 parts by mass or more, more preferably 6 parts by mass or more, even more preferably 9 parts by mass or more, and preferably 25 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, a better effect tends to be obtained.

[0111] 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 from companies such as Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd. can be used. These can be used individually or in combination of two or more types.

[0112] It is presumed that when the above rubber composition contains a mercapto-silane coupling agent, fuel efficiency during city driving tends to improve.

[0113] 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.

[0114] 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 h has an average value of 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.)

[0115] 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. 1004Examples 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. 1004 Preferably, 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] In the above-mentioned rubber composition for tires, the content of the silane coupling agent is preferably 1 part 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 silica, 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.

[0123] The above rubber composition preferably contains a plasticizer. 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 include resins, oils, liquid rubber, and ester-based plasticizers. Among these, resins are 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.

[0124] It is presumed that when the above rubber composition contains resin, its fuel efficiency during city driving tends to improve.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] It is presumed that when the product contains at least one resin selected from the group consisting of cyclopentadiene resins, aromatic vinyl resins, and terpene resins, fuel efficiency during city driving tends to improve.

[0129] 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 isoprene, pentane, isopentane, neopentane, pentene, and pentadiene. These C5 resins may be used individually or in combination of two or more types.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] There are no particular limitations on the method for confirming whether the acylglycerol is contained in the tire rubber composition, 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] In the above rubber composition, the plasticizer content (total amount of plasticizer such as resin and liquid rubber) is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 35 parts by mass or more, and preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 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. On the other hand, from the viewpoint of improving processability, the amount is preferably 27 parts by mass or more, more preferably 32 parts by mass or more, and even more preferably 37 parts by mass or more. Furthermore, from the viewpoint of improving wear resistance, the amount is preferably 37 parts by mass or less, more preferably 32 parts by mass or less, and even more preferably 27 parts by mass or less.

[0154] When the above 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 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 35 parts by mass or less, more preferably 25 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, a better effect tends to be obtained.

[0155] When the above 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 5 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.

[0156] When the above 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 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 35 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 15 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 processability, the amount is preferably 9 parts by mass or more, more preferably 14 parts by mass or more, and even more preferably 18 parts by mass or more. Furthermore, from the viewpoint of improving wear resistance, the amount is preferably 18 parts by mass or less, more preferably 14 parts by mass or less, and even more preferably 9 parts by mass or less.

[0157] When the above 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 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 35 parts by mass or less, more preferably 25 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.

[0158] When the above 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 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 35 parts by mass or less, more preferably 25 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. Furthermore, the amount of resin contained in the liquid state includes the amount of resin contained in the resin-stretched rubber.

[0159] When the above rubber composition contains oil in a liquid state under conditions of 1 atmosphere and 25°C, the oil content is preferably 5 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 45 parts by mass or less, more preferably 35 parts by mass or less, and even more preferably 25 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.

[0160] When the above 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.

[0161] The above rubber composition preferably contains liquid rubber. The liquid rubber may have a weight-average molecular weight (Mw) of 10,000 or more, i.e., be a rubber component, or it may have an Mw of less than 10,000, i.e., be a plasticizer, but it is preferable that the Mw is 10,000 or more. Examples of liquid rubber with an Mw of 10,000 or more include those described above regarding the rubber components. Examples of liquid rubber with an Mw of less than 10,000 include those described above regarding the plasticizers.

[0162] It is presumed that when the above rubber composition contains liquid rubber, fuel efficiency during city driving tends to improve.

[0163] The liquid rubber described above is preferably a carboxylic acid-modified diene rubber. Examples of carboxylic acid-modified diene rubbers include those described above for their rubber components. It is presumed that if the liquid rubber is a carboxylic acid-modified diene rubber, fuel efficiency during city driving tends to improve.

[0164] The above-mentioned tire rubber composition may contain a fatty acid derivative. 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] Examples of the above-mentioned fatty acid derivatives include products from companies such as Rhein Chemie and Structol.

[0173] The content of the above fatty acid derivative is preferably 2.0 parts by mass or more, more preferably 4.0 parts by mass or more, even more preferably 5.5 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, the effect tends to be better obtained.

[0174] 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.

[0175] The vulcanized rubber particles are not particularly limited and may be either unmodified or modified vulcanized rubber particles.

[0176] Commercially available vulcanized rubber particles can be used, for example, products from Lehigh, Muraoka Rubber Industries, Ltd., and others.

[0177] 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.

[0178] The above-mentioned rubber composition for tires preferably contains an anti-aging agent from the viewpoint of crack resistance, ozone resistance, etc.

[0179] 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.

[0180] 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 4.0 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.

[0181] The above tire rubber composition may contain stearic acid. In the above-mentioned rubber composition for tires, the stearic acid content is preferably 1.0 part by mass or more, more preferably 1.5 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.

[0182] 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.

[0183] 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 1.5 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.

[0184] 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.

[0185] The above-mentioned rubber composition for tires may contain sulfur. In the above-mentioned rubber composition for tires, the sulfur content is preferably 0.4 parts by mass or more, more preferably 0.8 parts by mass or more, even more preferably 1.0 part by mass or more, per 100 parts by mass of the rubber component, and also 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. When the content is within the above range, a better effect tends to be obtained.

[0186] 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.

[0187] 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 1.0 part by mass or more, more preferably 3.0 parts by mass or more, and even more preferably 4.5 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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] The tread of the above-mentioned tire has a first land portion that is closest to the equator and a second land portion that is located further out than the first land portion, on the outer side of the vehicle from the tire's equator. In this specification, the outer side 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.

[0197] "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.

[0198] "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.

[0199] The "width W1 of the first land portion closest to the equator on the vehicle outer side of the tire equator" and the "width W2 of the second land portion disposed outside the first land portion" respectively refer to the widths of the "first land portion closest to the equator on the vehicle outer side of the tire equator" and the "second land portion disposed outside the first land portion" specified by the above definitions.

[0200] In this specification, the land portion refers to a portion intended to contact the road surface among regions sandwiched by two main grooves or one main groove and the ground contact end in the tire width direction.

[0201] In this specification, the main groove refers to a groove continuous in the tire circumferential direction, and among them, a groove having a cross-sectional area perpendicular to the tire circumferential direction of 10 mm 2 or more. Note that the shape of the groove may be a straight line parallel to the tire circumferential direction, a wavy line, or a straight line (zigzag shape) bent multiple times.

[0202] Since the tire of the present invention has two or more land portions on the vehicle outer side of the tire equator, at least one or more main grooves exist outside the tire equator.

[0203] In addition, since the low fuel consumption performance during urban driving, which is an effect of the present invention, is greatly contributed by the land portion on the vehicle outer side of the tire equator, an arbitrary pattern may be formed on the vehicle inner side of the tire equator. It is preferable that the tread of the above tire also satisfies a similar relationship for the land portion on the vehicle inner side of the tire equator. That is, it is preferable to satisfy formula (1) even when the tire is mounted on the vehicle with the inner and outer sides of the tire swapped.

[0204] FIG. 1 is a developed view of the tread portion of one embodiment of the above tire. In FIG. 1, the right side is the outer side in the tire axial direction, and the left side is the inner side in the tire axial direction.

[0205] The tread portion is provided with at least two main grooves. As shown in FIG. 1, three main grooves 2 are provided in this embodiment. The main grooves 2 include a main groove 2B extending on the tire equator C, and main grooves 2A and 2C extending on both outer sides of the main groove 2B. Each main groove 2 extends linearly and continuously in the tire circumferential direction.

[0206] By each main groove 2, the land portions 1 of the tread portion are divided into four, 1A to 1D. In FIG. 1, the land portion 1C located on the outer side of the vehicle of the main groove 2B corresponds to "the first land portion that is closest to the equator on the outer side of the vehicle from the tire equator", and the land portion 1D arranged on the outer side in the tire axial direction of the main groove 2C corresponds to "the second land portion arranged outside the first land portion".

[0207] In the above tire, the width W1 of the first land portion that is closest to the equator on the outer side of the vehicle from the tire equator is preferably 10 mm or more, more preferably 15 mm or more, still more preferably 22 mm or more, and is preferably 35 mm or less, more preferably 30 mm or less, still more preferably 25 mm or less. When it is within the above range, the effect tends to be obtained more favorably.

[0208] In the above tire, the width W2 of the second land portion arranged outside the first land portion is preferably 15 mm or more, more preferably 20 mm or more, still more preferably 26 mm or more, and is preferably 40 mm or less, more preferably 35 mm or less, still more preferably 30 mm or less. When it is within the above range, the effect tends to be obtained more favorably.

[0209] In the above tire, W1 / W2 > 0.3. (The value on the left side) is preferably 0.4 or more, more preferably 0.6 or more, still more preferably 0.8 or more, and is preferably 2.0 or less, more preferably 1.5 or less, still more preferably 1.0 or less. When it is within the above range, the effect tends to be obtained more favorably. In this relationship, W1 is the width (in mm) of the first land portion closest to the equator, located outside the tire's equator on the vehicle's exterior, and W2 is the width (in mm) of the second land portion located outside the first land portion.

[0210] For the above tire, (W1-W2×0.3)×(PC+AE-BC-Ash)>100. The value of (left side) is preferably greater than 200, more preferably 350 or more, even more preferably 450 or more, and also preferably 700 or less, more preferably 600 or less, and even more preferably 500 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 wet grip performance, the values ​​are preferably 242 or higher, more preferably 249 or higher, even more preferably 261 or higher, even more preferably 279 or higher, even more preferably 299 or higher, even more preferably 401 or higher, even more preferably 402 or higher, and even more preferably 471 or higher. Furthermore, from the viewpoint of improving wear resistance, the values ​​are preferably 472 or lower, more preferably 403 or lower, even more preferably 402 or lower, even more preferably 300 or lower, even more preferably 280 or lower, even more preferably 262 or lower, even more preferably 250 or lower, and even more preferably 243 or lower. In this relationship, W1 is the width (in mm) of the first land portion closest to the equator, located outside the tire's equator on the vehicle's exterior, W2 is the width (in mm) of the second land portion located outside the first land portion, and PC, AE, BC, and Ash are the values ​​(in mass%) mentioned above. [Examples]

[0211] The following examples (implementations) are considered preferable for implementation, but the scope of the present invention is not limited to these examples.

[0212] The various chemicals used in the examples and comparative examples are described below. NR:TSR20 Liquid IR: LIR-410 (maleic acid-modified liquid polyisoprene, Mw30000) manufactured by Kuraray Co., Ltd. SBR1: HPR850 manufactured by JSR Corporation (Tg -24℃, styrene content 27.5% by mass, vinyl content 59% by mass) SBR2: HPR830E manufactured by JSR Corporation (Tg -23℃, styrene content 39.5% by mass, vinyl content 38.5% by mass, oil content 10 parts by mass per 100 parts by mass of rubber solids) SBR3: HPR840 manufactured by JSR Corporation (Tg -60℃, 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: 111 m²) 2 / g) Silica 1: Evonik ULTRASIL VN3 (CTAB specific surface area 170 m²) 2 / g) Silica 2: Solvay's Zeosil Premium SW (CTAB specific surface area 245 m²) 2 / g) Magnesium sulfate: MN-00 (anhydrous magnesium sulfate, median particle size 75 μm) manufactured by Mai Kasei Kogyo Co., Ltd. Silane coupling agent 1: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik. Silane coupling agent 2: NXT (3-octanoylthiopropyltriethoxysilane) manufactured by Momentive Ionic coupling agent: X-12-1126 (quaternary ammonium salt, hydrolysate of the compound represented by formula (1), compound represented by formula (1-1)) manufactured by Shin-Etsu Chemical Co., Ltd. Oil: H&R VIVATEC500 Resin 1: Oppera PR-383 (hydrogenated DCPD-C9 resin) manufactured by Exxon Mobil Resin 2: Sylvatraxx 4401 (a copolymer of α-methylstyrene and styrene) manufactured by Arizona Chemical Corporation. Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. Fatty acid derivative 1: WB16 manufactured by Structol (a mixture of fatty acid metal salts (calcium fatty acid, constituent fatty acids: saturated fatty acids with 14-20 carbon atoms) and fatty acid amides) Fatty acid derivative 2: Activator 73A manufactured by Structol (a mixture of zinc salts of aliphatic carboxylic acids and aromatic carboxylic acids) Anti-aging agent 1: Nocrack 6C (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) (6PPD) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Anti-aging agent 2: Anti-aging agent 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 oxide No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: HK-200-5 (5% by mass oil-containing powdered sulfur) manufactured by Hosoi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noxellar CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noxellar D (diphenylguanidine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0213] <Examples and Comparative Examples> (Base mixing process) According to the formulation shown in Table 1, the materials are placed in a Banbury mixer and kneaded. After kneading for 2 minutes at a rubber temperature of 160°C, the mixture is discharged. Only the mixture (sheet rubber) obtained from the discharge is put into a Banbury mixer and kneaded further (discharge temperature 160°C). (Final mixing 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 obtain a test tire.

[0214] The test tires are evaluated as follows. The results are shown in Table 1. In the following evaluation method, when calculating the index, Comparative Example 2 is used as the evaluation criterion.

[0215] In the table, the rubber content in the oil-extended rubber is described in the rubber column, and the oil content in the oil-extended rubber is added to the oil column.

[0216] Also, the tire sizes in Table 1 are as follows. Table 1: 245 / 45R18

[0217] Also, W1, W2, and W1 / W2 in Table 1 are as follows. Table 1: W1: 22 mm, W2: 26 mm, W1 / W2: 0.846

[0218] (Low fuel consumption performance during urban driving) Each test tire is assembled on a regular rim and filled with the regular internal pressure. Each test tire is mounted on all wheels of the vehicle and driven on the dry road surface of a test course simulating a driving state close to urban areas. After driving a predetermined distance, the reduction rate of fuel is measured and expressed as an index with the evaluation criterion set to 100. The larger the index, the better the low fuel consumption performance during urban driving.

[0219]

Table 1

[0220] The present invention (1) is a tire having a tread, where the tread is composed of a rubber composition for tires containing a rubber component including a carboxylic acid-modified diene rubber, a filler including silica, 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, and is a tire satisfying the following (1) to (3). (1) The amount of polymer (PC), acetone extract (AE), carbon black (BC), and ash (Ash) in the rubber composition is (PC + AE) / (BC + Ash) > 1 (2) When the width of the first land area is W1 and the width of the second land area is W2, W1 / W2 > 0.3 (3)(W1-W2×0.3)×(PC+AE-BC-Ash)>100

[0221] The present invention (2) is the tire according to the present invention (1), wherein the rubber component contains styrene-butadiene rubber, and the amount of styrene in the styrene-butadiene rubber is 25% by mass or more.

[0222] The present invention (3) is the tire according to the present invention (2), wherein the styrene content of the styrene-butadiene rubber is 30% by mass or more.

[0223] The present invention (4) relates to the silica having a CTAB specific surface area of ​​200 m². 2 A tire in any combination with any of the present invention (1) to (3) which is 1 / g or more.

[0224] The present invention (5) is a tire in any combination of the present invention (1) to (4), wherein the silica content per 100 parts by mass of the rubber component is 100 parts by mass or more.

[0225] The present invention (6) is a tire in any combination of the rubber composition containing a resin with any of the present inventions (1) to (5).

[0226] The present invention (7) is a tire according to the present invention (6), wherein the resin is at least one selected from the group consisting of dicyclopentadiene resins, aromatic vinyl resins, and terpene resins.

[0227] The present invention (8) is a tire in any combination of the rubber composition containing a mercapto-silane coupling agent with any of the present inventions (1) to (7).

[0228] The present invention (9) is a tire in any combination of the rubber component with any of the present inventions (1) to (8), wherein the rubber component contains liquid rubber.

[0229] The present invention (10) is a tire in any combination of the rubber composition containing a water-soluble filler with any of the present inventions (1) to (9).

[0230] The present invention (11) is a tire according to the present invention (9), wherein the liquid rubber is the carboxylic acid-modified diene rubber.

[0231] Invention (12) is a tire in any combination with any of Inventions (1) to (11) such that (W1-W2×0.3)×(PC+AE-BC-Ash)>200.

[0232] Invention (13) is a tire in any combination with any of Inventions (1) to (12) such that (PC+AE) / (BC+Ash) > 1.5. [Explanation of Symbols]

[0233] 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 a carboxylic acid-modified diene rubber, a filler containing silica, 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. A tire that satisfies the following conditions (1) to (3). (1) Regarding the amount of polymer (PC), acetone extract (AE), carbon black (BC), and ash (Ash) in the rubber composition, (PC + AE) / (BC + Ash) > 1 (2) When the width of the first land area is W1 and the width of the second land area is W2, W1 / W2 > 0.3 (3) (W1-W2×0.3)×(PC+AE-BC-Ash)>100

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

3. The tire according to claim 2, wherein the amount of styrene in the styrene-butadiene rubber is 30% by mass or more.

4. The CTAB specific surface area of ​​the aforementioned silica is 200 m². ２ The tire according to claim 1 or 2, wherein the weight is 1 / g or more.

5. The tire according to claim 1 or 2, wherein the silica content relative to 100 parts by mass of the rubber component is 100 parts by mass or more.

6. The tire according to claim 1 or 2, wherein the rubber composition contains a resin.

7. The tire according to claim 6, wherein the resin is at least one selected from the group consisting of dicyclopentadiene resins, aromatic vinyl resins, and terpene resins.

8. The tire according to claim 1 or 2, wherein the rubber composition contains a mercapto-silane coupling agent.

9. The tire according to claim 1 or 2, wherein the rubber composition contains liquid rubber.

10. The tire according to claim 1 or 2, wherein the rubber composition contains a water-soluble filler.

11. The tire according to claim 9, wherein the liquid rubber is the carboxylic acid-modified diene rubber.

12. The tire according to claim 1 or 2, wherein (W1 - W2 × 0.3) × (PC + AE - BC - Ash) > 200.

13. The tire according to claim 1 or 2, wherein (PC + AE) / (BC + Ash) > 1.5.

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