Tire

Abstract

Provided is a tire having excellent comprehensive performance of handling stability, wear resistance, and fuel economy. The present invention relates to a tire and, more specifically, to a tire provided with a tire member comprising a rubber composition containing a rubber component and carbon black containing regenerated carbon black, the rubber composition containing a nitrogen-containing compound, the nitrogen content being 0.20 parts by mass or more with respect to 100 parts by mass of the rubber component, and the content of nitrogen being 0.20 parts by mass or more with respect to 100 parts by mass of the rubber component, and the content of nitrogen being 0.20 parts by mass or more with respect to 100 parts by mass of the rubber component. The carbon black content A (parts by mass), the nitrogen content B (parts by mass), and the maximum thickness C (mm) of the tire member satisfy the following formula (1): (1) A * B / Cgt; and 0.5.

Description

Technical Field

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

[0002] Recently, from the viewpoint of environmental considerations and the like, improvements in fuel efficiency, steering stability, wear resistance, and the like are desired for tires. Summary of the invention Problems to be solved by the invention

[0003] However, fuel economy, handling stability, and wear resistance are generally conflicting properties and therefore it is difficult to improve them in a balanced manner.

[0004] An object of the present invention is to solve the above-mentioned problems and to provide a tire having excellent comprehensive performance in terms of handling stability, wear resistance and low fuel consumption. Technical solutions to the problem

[0005] The present invention relates to a tire comprising a tire component composed of the following rubber composition, wherein the rubber composition contains a rubber component and carbon black including regenerated carbon black, The rubber composition contains a nitrogen-containing compound, The nitrogen content is 0.20 parts by mass or more relative to 100 parts by mass of the rubber component. The carbon black content A (parts by mass), the nitrogen content B (parts by mass), and the maximum thickness C (mm) of the tire component relative to 100 parts by mass of the rubber component satisfy the following formula (1): (1)A×B / C>0.5. Effects of the Invention

[0006] The present invention can provide a tire having tire parts composed of the following rubber composition, wherein the rubber composition contains a rubber component and carbon black containing regenerated carbon black, the rubber composition contains a nitrogen-containing compound, the nitrogen content is 0.20 parts by mass or more relative to 100 parts by mass of the rubber component, and the content A (parts by mass) of the carbon black, the nitrogen content B (parts by mass), and the maximum thickness C (mm) of the tire parts relative to 100 parts by mass of the rubber component satisfy the above formula (1), thereby being a tire with excellent comprehensive performance of low fuel consumption and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a cross-sectional view showing a part of a pneumatic tire. Figure 2 It shows Figure 1 An enlarged cross-sectional view of the tire near the tread. Description of Reference Numerals 2 tire 4 tread 6 sidewall 8 tire wing 10 lap 12 bead 14 carcass 16 belt layer 18 belt layer 20 inner liner 22 bead cover 26 groove 28 base layer 30 crown layer 32 bead core 34 bead apex strip 36 carcass ply 36a main body 36b folded portion 38 inner layer 40 outer layer 42 Main groove 44 Pattern 46 Sidewall surface CL Tire equatorial plane T Sidewall thickness D is the main groove depth of the circumferential main groove formed on the tread. DETAILED DESCRIPTION

[0008] The above-mentioned tire has a tire component composed of the following rubber composition, wherein the rubber composition contains a rubber component and a rubber composition of carbon black containing recycled carbon black, the rubber composition contains a nitrogen-containing compound, the nitrogen content is 0.20 parts by mass or more relative to 100 parts by mass of the rubber component, and the carbon black content A (parts by mass) and the nitrogen content B (parts by mass) relative to 100 parts by mass of the rubber component, and the maximum thickness C (mm) of the tire component satisfies the formula (1) "A×B / C>0.5".

[0009] The mechanism (reason) by which the above-mentioned effects are obtained by the above-mentioned tire is not necessarily clear, but is presumed as follows. When regenerated carbon black and nitrogen-containing compounds are used, the total acid content of the regenerated carbon black is greater than that of conventional carbon black, and the reactivity with basic substituents is high. Therefore, the basic substituents (isocyanates, etc.) further react with the acidic groups of the regenerated carbon black to modify the surface of the regenerated carbon black with substituents (aromatic rings, etc.) that interact with the polymer, thereby improving the affinity with the polymer and greatly improving the reinforcement. In addition, by improving the compatibility with polymers, the dispersibility of carbon black can be improved, thereby improving fuel efficiency. Furthermore, by improving the reinforcement, the tire components can be made thinner, and the fuel efficiency can be further improved by reducing the weight. Therefore, it is speculated that when the regenerated carbon black and the nitrogen-containing compound are contained in a specified ratio, and when the carbon black content A, the nitrogen content B, and the maximum thickness C of the tire components satisfy the formula (1) "A×B / C>0.5", the above mechanism can improve the reinforcement and low fuel consumption in a well-balanced manner, and the comprehensive performance of handling stability, wear resistance and low fuel consumption is improved.

[0010] In this way, the tire is constructed to satisfy the relationship "A×B / C>0.5", thereby solving the problem (purpose) of improving the comprehensive performance of handling stability, wear resistance and low fuel consumption. That is, the parameter "A×B / C>0.5" is not the problem (purpose) of the present invention. The problem of the present application is to improve the comprehensive performance of handling stability, wear resistance and low fuel consumption. As a technical means to solve this problem, a structure that satisfies this parameter is adopted.

[0011] The above tire has tire components composed of a rubber composition. Hereinafter, chemical substances that can be used in the above-mentioned rubber composition will be described.

[0012] The rubber composition contains a rubber component. Here, the rubber component is a component that contributes to crosslinking, and generally, a polymer having a weight average molecular weight (Mw) of 10,000 or more and a polymer component that cannot be extracted by acetone corresponds to the rubber component. The rubber component is in a solid state at room temperature (25° C.).

[0013] The weight average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, further preferably 200,000 or more, particularly preferably 270,000 or more, and is preferably 2,000,000 or less, more preferably 1,500,000 or less, further preferably 1,000,000 or less. When it is within the above range, better effects tend to be obtained.

[0014] It should be noted that in this specification, the weight average molecular weight (Mw) can be obtained by conversion to standard polystyrene based on the measured value using gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, chromatographic column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation). In addition, in the case of a polymer having a modified group, the modified group interacts with the silica gel of the chromatographic column and an accurate Mw cannot be obtained, so the Mw is measured before the modification treatment is performed.

[0015] The rubber component that can be used in the rubber composition may be an unmodified rubber or a modified rubber. Examples of modified rubbers include rubbers having functional groups that interact with fillers such as silica, etc. Examples include terminal-modified rubbers obtained by modifying at least one terminal of the rubber with a compound (modifier) ​​having the above functional groups (terminal-modified rubbers having the above functional groups at the terminals), main chain-modified rubbers having the above functional groups in the main chain, main chain-terminal-modified rubbers having the above functional groups in the main chain and the terminals (for example, main chain-terminal-modified rubbers obtained by modifying at least one terminal of the main chain with the above functional groups with the above modifiers), and terminal-modified rubbers into which hydroxyl groups and epoxy groups are introduced by modification (coupling) with a multifunctional compound having two or more epoxy groups in the molecule.

[0016] Examples of the functional group include amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazole, urea, ether, carbonyl, oxycarbonyl, mercapto, sulfide, disulfide, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imido, 1,2-hydrazine, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy, hydroxyl, oxy, epoxy, etc. It should be noted that these functional groups may have a substituent. Among them, amino (preferably an amino group in which the hydrogen atom possessed by the amino group is substituted by an alkyl group having 1 to 6 carbon atoms), alkoxy (preferably an alkoxy group having 1 to 6 carbon atoms), and alkoxysilyl (preferably an alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

[0017] As the above-mentioned rubber component, for example, diene rubber can be mentioned. As diene rubber, isoprene rubber, butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), etc. can be mentioned. In addition, as rubber components, butyl rubber, fluororubber, etc. can also be mentioned. They can be used alone or in combination of two or more. In addition, these rubber components can be modified and hydrogenated, and filled rubber filled with oil, resin, liquid rubber components, etc. can also be used. Among them, it is preferred to contain at least one of isoprene rubber, BR, and SBR, and it is more preferred to contain at least isoprene rubber.

[0018] As isoprene-based rubber, there are natural rubber (NR), polyisoprene rubber (IR), modified NR, modified NR, modified IR, etc. As NR, for example, SIR20, RSS#3, TSR20, etc., which are commonly used in the rubber industry, can be used. As IR, there is no particular limitation, for example, IR2200, etc., which are commonly used in the rubber industry, can be used. As modified NR, there are deproteinized natural rubber (DPNR), high purity natural rubber (UPNR), etc., as modified NR, there are epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc., as modified IR, there are epoxidized polyisoprene rubber, hydrogenated polyisoprene rubber, grafted polyisoprene rubber, etc. They can be used alone or in combination of two or more.

[0019] In the rubber composition, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and may be 100% by mass. When it is within the above range, better effects tend to be obtained.

[0020] BR is not particularly limited, for example, high cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, BR synthesized using a rare earth catalyst (rare earth BR), etc. can be used. They can be used alone or in combination of two or more. Among them, BR preferably contains a high cis BR with a cis content of 90% by mass or more. The cis content is more preferably 95% by mass or more. It should be noted that the cis content can be measured by infrared absorption spectroscopy.

[0021] The cis-amount of BR refers to the cis-amount of the BR when there is one type of BR, and refers to the average cis-amount when there are multiple types of BR. The average cis content of BR can be calculated as follows: {Σ(content of each BR×cis content of each BR)} / total content of all BRs. For example, when BR with a cis content of 90% by mass is 20% by mass and BR with a cis content of 40% by mass is 10% by mass in the rubber component of 100% by mass, the average cis content of BR is 73.3% by mass (=(20×90+10×40) / (20+10)).

[0022] In addition, BR may be either unmodified BR or modified BR. As modified BR, there may be mentioned modified BR introduced with the same functional group as the modified rubber. In addition, hydrogenated butadiene polymer (hydrogenated BR) may be used as BR.

[0023] As BR, for example, products of Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Corporation, etc. can be used.

[0024] When the rubber composition contains BR, the content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. When it is within the above range, better effects tend to be obtained.

[0025] The 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 can be used alone or in combination of two or more.

[0026] The styrene content of SBR is preferably 5% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass or more. The styrene content is preferably 60% by mass or less, more preferably 40% by mass or less, and further preferably 35% by mass or less. When within the above range, a better effect is tended to be obtained. It should be noted that, in this specification, the styrene content can be1 H-NMR was used for determination.

[0027] The styrene amount of SBR refers to the styrene amount of the SBR when the SBR is one type, and refers to the average styrene amount when the SBR is multiple types. The average styrene content of SBR can be calculated as follows: {Σ(content of each SBR×styrene content of each SBR)} / total content of all SBRs. For example, when SBR with a styrene content of 40 mass% is 85 mass% and SBR with a styrene content of 25 mass% is 5 mass% in 100 mass% of the rubber component, the average styrene content of SBR is 39.2 mass% (=(85×40+5×25) / (85+5)).

[0028] The vinyl bond content of SBR is preferably 3% by mass or more, more preferably 5% by mass or more, and further preferably 7% by mass or more. The vinyl bond content is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. When within the above range, a better effect is tended to be obtained. In addition, in this specification, the vinyl bond amount (1,2-bonded butadiene unit amount) can be measured by infrared absorption spectroscopic analysis.

[0029] The vinyl amount (1,2-bonded butadiene unit amount) of SBR is the ratio of vinyl bonds when the total mass of the butadiene part in SBR is 100 (unit: mass %), vinyl amount [mass %] + cis amount [mass %] + trans amount [mass %] = 100 [mass %]. When there is one type of SBR, it refers to the vinyl amount of the SBR, and when there are multiple types, it refers to the average vinyl amount. The average vinyl content of SBR can be calculated as follows: 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, in 100 parts by mass of the rubber component, SBR having 40% by mass styrene and 30% by mass vinyl content is 75 parts by mass, and SBR having 25% by mass styrene and 30% by mass vinyl content is 75 parts by mass. When the base amount of SBR is 15 parts by mass and the remaining 10 parts by mass are other than SBR, the average vinyl content of 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%])}.

[0030] SBR can use any one of non-modified SBR and modified SBR. As modified SBR, the modified SBR formed by introducing the same functional group as modified rubber can be enumerated. In addition, as SBR, hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used.

[0031] As SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Corporation, etc. can be used. In addition, SBR synthesized by a known method can also be used.

[0032] When the rubber composition contains SBR, the content of SBR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less. When within the above range, a better effect tends to be obtained.

[0033] It should be noted that the raw materials (monomers) of synthetic rubbers such as SBR and BR may also come from petroleum, or 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, and examples include: butadiene from recycling, aromatic vinyl compounds from recycling, etc. Examples of the butadiene include: 1,2-butadiene and 1,3-butadiene. The aromatic vinyl compounds are not particularly limited, but examples include styrene, etc. Among them, it is preferred to use butadiene from recycling (recycled butadiene) and / or styrene from recycling (recycled styrene) as raw materials.

[0034] There are no particular limitations on the method for producing the recycled monomer, and for example, the monomer may be synthesized from naphtha, a recycled source, obtained by decomposing rubber products such as tires. In addition, there are no particular limitations on the method for producing naphtha, a recycled source, and for example, rubber products such as tires may be decomposed under high temperature and high pressure, may be decomposed using microwaves, or may be mechanically crushed and then extracted.

[0035] Furthermore, the raw materials (monomers) of synthetic rubbers such as SBR and BR can also come from biomass. As monomers from biomass (biomass monomers), there are no particular limitations, and examples include: butadiene from biomass, aromatic vinyl compounds from biomass, etc. As the butadiene, there are 1,2-butadiene and 1,3-butadiene. As the aromatic vinyl compound, there are no particular limitations, and examples include styrene, etc. In addition, the method for producing biomass monomers is not particularly limited, and for example, methods through biological and / or chemical and / or physical transformations of animals and plants can be cited. As a biological transformation, the transformation using microbial fermentation is representative, and as a chemical and / or physical transformation, there are exemplified: transformation using a catalyst, transformation using high heat, transformation using high pressure, transformation using electromagnetic waves, transformation using critical liquids, and combinations thereof. As biomass sources of these monomers, there are exemplified: sugar, wood, plant residues after obtaining useful components, ethanol from plants, biomass naphtha, etc.

[0036] The polymer synthesized from the biomass monomer component (biomass polymer) is not particularly limited, and examples thereof include: polybutadiene rubber synthesized from butadiene from biomass, aromatic vinyl / butadiene copolymers synthesized from butadiene from biomass and / or aromatic vinyl compounds from biomass, etc. Examples of the aromatic vinyl / butadiene copolymer include, for example, styrene-butadiene rubber synthesized from butadiene from biomass and / or styrene from biomass, etc.

[0037] Whether the raw material of a polymer is derived from biomass can be determined by pMC (percent Modern Carbon) measured according to ASTM D6866-10.

[0038] pMC is the sample 14 C concentration and modern standard reference 14 The ratio of C concentration is used as an index to indicate the biomass ratio of the compound (rubber). The meaning of this value is as follows.

[0039] In 1 mol of carbon atoms (6.02×10 23 There are about 6.02×10 carbon atoms, which is about one trillionth of the normal carbon atoms. 11 indivual 14 C. 14 C is called a radioactive isotope, and its half-life is 5730 years and it decreases regularly. It takes 226,000 years for all of them to decay. Therefore, after carbon dioxide in the atmosphere is absorbed and fixed by plants, etc., it has been fixed in fossil fuels such as coal, oil, and natural gas for more than 226,000 years.14 The C element has completely decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas do not contain any C. 14 Therefore, the chemical substances produced from these fossil fuels do not contain 14 Element C.

[0040] on the other hand, 14 C is continuously produced by cosmic rays in the atmosphere through nuclear reactions, which is balanced by the reduction caused by radioactive decay. In the Earth's atmospheric environment, 14 The amount of C is constant. Therefore, in the current environment, the amount of substances from biomass resources in the material cycle is 14 As mentioned above, the C concentration is about 1×10 -12 Therefore, the ratio (biomass ratio) of a compound derived from a natural resource (a compound derived from a biomass resource) in a certain compound (rubber) can be calculated using the difference between these values.

[0041] Should 14 C is usually measured as follows. Using tandem accelerator-based accelerator mass spectrometry, 13 C concentration ( 13 C / 12 C) 14 C concentration ( 14 C / 12 C) determination. In the determination, as a 14 The standard modern carbon based on the concentration of C is based on the circulating carbon in nature in 1950. 14 C concentration. As a specific standard substance, an oxalic acid standard provided by NIST (National Institute of Standards and Technology) was used. The specific radioactivity of carbon in the oxalic acid (per gram of carbon) 14 The radioactivity intensity of C is divided into 13 C correction is fixed, and the decay-corrected value from 1950 AD to the measurement date is used as the standard 14 The ratio of this value to the value of the sample actually measured is the pMC value.

[0042] Therefore, if rubber is made from 100% biomass (natural), it will show a value of about 110 pMC (currently, it will not be 100 in most cases under normal conditions) despite regional differences. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring this 14In the case of C concentration, it will show about 0 pMC (for example, 0.3 pMC). This value corresponds to the above-mentioned biomass ratio of 0%.

[0043] In summary, it is preferable from the perspective of environmental protection to use rubber or other materials having a high pMC value, that is, rubber or other materials having a high biomass ratio, in a rubber composition.

[0044] The rubber composition contains at least regenerated carbon black (recycled carbon black) as carbon black. The carbon black may be used alone or in combination of two or more. It should be noted that, in this specification, regenerated carbon black refers to carbon black recovered by thermally decomposing used rubber products containing carbon black.

[0045] As the regenerated carbon black, for example, regenerated carbon black produced by thermal decomposition of waste tires can be cited. The thermal decomposition of waste tires can be carried out by a known method, for example, a thermal decomposition method at a temperature of 650° C. or above can be cited. Specifically, the recycled carbon black containing hydroxyl and / or carboxyl groups on its surface obtained by thermal decomposition of tires disclosed in European Patent Application Publication No. 3173251 can be cited. The regenerated carbon black can be used alone or in combination of two or more.

[0046] The average primary particle size of the regenerated carbon black is preferably 30 nm or more, more preferably 35 nm or more, and preferably 65 nm or less, more preferably 60 nm or less, and further preferably 55 nm or less. When it is within the above range, better effects tend to be obtained. In this specification, the average primary particle size of carbon black can be determined by measuring 400 or more primary particles of carbon black observed in a field of view through a transmission or scanning electron microscope and averaging the measured values.

[0047] Regenerated carbon black can be commercially available, for example, PB365 manufactured by Enrestec. PB365 is a regenerated carbon black produced by thermal decomposition of waste tires. 2 SA is 76m 2 / g. In addition, PB365 contains about 17% by mass of ash.

[0048] In the rubber composition, the content of the regenerated carbon black is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, particularly preferably 40 parts by mass or more, and preferably 150 parts by mass or less, more preferably 100 parts by mass or less, further preferably 80 parts by mass or less, relative to 100 parts by mass of the rubber component. When within the above range, a better effect tends to be obtained.

[0049] The rubber composition may contain carbon black other than regenerated carbon black (hereinafter also referred to as conventional carbon black). As such conventional carbon black (new carbon black), there is no particular limitation, but can be cited: N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Co., Ltd., Shin Nichia Carbon Co., Ltd., Columbia Carbon Co., Ltd., etc. can be used. They can be used alone or in combination of two or more. In addition, in addition to using carbon black made from conventional mineral oils, etc. as raw materials, carbon black made from biomass materials such as lignin as raw materials can also be used.

[0050] Nitrogen adsorption specific surface area of ​​conventional carbon black (N 2 SA) is preferably 5m 2 / g or more, more preferably 10m 2 / g or more, more preferably 15m 2 / g or more. In addition, the above N 2 SA is preferably 130m 2 / g or less, more preferably 120m 2 / g or less, more preferably 100m 2 When it is within the above range, better effects tend to be obtained. In addition, the nitrogen adsorption specific surface area of ​​carbon black is calculated|required based on JIS K6217-2:2001.

[0051] The average primary particle size of conventional carbon black is preferably 10 nm or more, more preferably 30 nm or more, and preferably 100 nm or less, more preferably 80 nm or less, further preferably 70 nm or less. When within the above range, better effects tend to be obtained.

[0052] In the rubber composition, the content of conventional carbon black is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 10 parts by mass or more, and preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and further preferably 30 parts by mass or less, relative to 100 parts by mass of the rubber component. When within the above range, better effects tend to be obtained.

[0053] In the rubber composition, the carbon black content A (the total content of regenerated carbon black and other carbon black) is preferably 2 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 30 parts by mass or more, and preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and further preferably 80 parts by mass or less, relative to 100 parts by mass of the rubber component. When it is within the above range, a better effect tends to be obtained.

[0054] The mechanism for obtaining a better effect when the carbon black is contained in a prescribed amount or more, especially 30 parts by mass or more, is not clear. It is believed that when the regenerated carbon black is not mixed, the reinforcement is greatly reduced, so by mixing the carbon black containing the regenerated carbon black in a prescribed amount, a significant reinforcement improvement effect can be exerted. Therefore, it is speculated that the comprehensive performance of handling stability, wear resistance and low fuel consumption is improved.

[0055] In the rubber composition, the content of regenerated carbon black in 100% by mass of carbon black (in 100% by mass of the total amount of regenerated carbon black and other carbon black) is preferably 50% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more. The upper limit is not particularly limited and may be 100% by mass, but is preferably 95% by mass or less, and more preferably 90% by mass or less. When within the above range, a better effect tends to be obtained.

[0056] In the rubber composition, the average primary particle size of carbon black (the average primary particle size of the entire carbon black) is preferably 10 nm or more, more preferably 30 nm or more, and preferably 100 nm or less, more preferably 60 nm or less, and further preferably 40 nm or less. When within the above range, a better effect tends to be obtained.

[0057] It should be noted that, in the present specification, the average primary particle size of carbon black (the average primary particle size of the carbon black as a whole) can be calculated as follows: {Σ(content of each carbon black × average primary particle size of each carbon black)} / total content of total carbon black. For example, relative to 100 parts by mass of the rubber component, when conventional carbon black with an average primary particle size of 66 nm is 10 parts by mass and regenerated carbon black with an average primary particle size of 35 nm is 40 parts by mass, the average primary particle size of the carbon black as a whole is 41 nm (= (66×10+35×40) / (10+40)).

[0058] The mechanism for obtaining a better effect within the specified range, especially when the average primary particle size of the carbon black as a whole is 30 nm or more and 60 nm or less, is unclear. It can be considered that the larger the particle size of the regenerated carbon black, the greater the reduction in reinforcement when not mixed. Therefore, by mixing the carbon black containing the regenerated carbon black, a significant reinforcement improvement effect can be exerted. Therefore, it is speculated that the comprehensive performance of handling stability, wear resistance and low fuel consumption is improved.

[0059] The rubber composition may contain a filler other than carbon black. Such fillers are not particularly limited, and materials known in the rubber field can be used, for example, inorganic fillers such as silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide, alumina, and mica, biochar, and poorly dispersible fillers, etc. Among them, silica is preferred from the viewpoint of obtaining a better effect.

[0060] In the rubber composition, the content of the filler (the total amount of fillers such as carbon black and silica) is preferably 2 parts by mass or more, more preferably 30 parts by mass or more, and further preferably 50 parts by mass or more, and is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and further preferably 100 parts by mass or less, relative to 100 parts by mass of the rubber component. When it is within the above range, better effects tend to be obtained.

[0061] In the rubber composition, there is no particular limitation on the silica that can be used. For example, silica prepared by a dry method (anhydrous silica), silica prepared by a wet method (hydrous silica), and other silicas commonly used in the tire industry can be used. As the raw material of silica, there is no particular limitation. For example, it can be a raw material from a mineral source such as quartz, a raw material from a biological source such as rice husk (for example, silica made from biomass materials such as rice husk as raw materials, etc.), or silica recycled and reused from a product containing silica can be used. Among them, from the reason that there are many silanol groups, hydrous silica prepared by a wet method is preferred. These silicas can be used alone or in combination of two or more.

[0062] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and filtering, washing, drying, and pulverizing the silica precipitate generated by reacting the silicate with sulfuric acid in the same manner as conventional wet silica.

[0063] Silica recovered and reused from products containing silica can be, for example, silica recovered from electronic parts such as semiconductors, tires, desiccants, diatomaceous earth and other silica-containing products. In addition, the recovery method is not particularly limited, and thermal decomposition, decomposition using electromagnetic waves, etc. can be cited. Among them, silica recovered from electronic parts such as semiconductors or tires is preferred.

[0064] When silicon dioxide crystallizes, it becomes insoluble in water, and the silicic acid that is its component cannot be used. By controlling the combustion temperature and combustion time, the crystallization of silicon dioxide in rice husk ash can be suppressed (see Japanese Patent Publication No. 2009-2594, Akita Prefectural University Online Journal B / 2019, vol. 6, p. 216-222, etc.).

[0065] Amorphous silica extracted from rice husks may be commercially available products such as those produced by Wilmar.

[0066] When the rubber composition contains silica, the content of silica is preferably 2 parts by mass or more, more preferably 6 parts by mass or more, and further preferably 20 parts by mass or more, and is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, and further preferably 100 parts by mass or less, relative to 100 parts by mass of the rubber component. When it is within the above range, better effects tend to be obtained.

[0067] The nitrogen adsorption specific surface area of ​​silicon dioxide (N 2 SA) is preferably 50m 2 / g or more, more preferably 100m 2 / g or more, more preferably 150m 2 / g or more. In addition, N 2 The upper limit of SA is not particularly limited, but is preferably 350 m 2 / g or less, more preferably 300m 2 / g or less, more preferably 250m 2 When it is within the above range, better effects tend to be obtained. It should be noted that the N 2 SA is a value measured by the BET method according to ASTM D3037-93.

[0068] Examples of the poorly dispersible filler include microfibrillated plant fibers, short-fiber cellulose, and gel compounds. Among them, microfibrillated plant fibers are preferred.

[0069] As the microfibrillated plant fibers, cellulose fibrils are preferred from the perspective of obtaining good reinforcement. As cellulose fibrils, there are no particular restrictions as long as they are derived from natural products, and examples thereof include: in addition to resource biomass such as fruits, grains, and root vegetables, wood fiber, bamboo fiber, hemp fiber, jute fiber, kenaf fiber, and waste biomass such as pulp, paper, cloth, crop residues, food waste, and sewage sludge obtained from these as raw materials, unused biomass such as straw, wheat straw, and thinning materials, cellulose produced by sea squirts, acetic acid bacteria, etc. These microfibrillated plant fibers can be used alone or in combination of two or more.

[0070] It should be noted that, in this specification, cellulose fibrils typically refer to cellulose fibers having an average fiber diameter of 10 μm or less, and more typically refer to cellulose fibers having a microstructure with an average fiber diameter of 500 nm or less formed by aggregation of cellulose molecules. Typical cellulose fibrils are formed, for example, as aggregates of cellulose fibers having the above-mentioned average fiber diameter.

[0071] In the case where the rubber composition contains a poorly dispersible filler, the content of the poorly dispersible filler is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more, relative to 100 parts by mass of the rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, further preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less. When within the above range, a better effect tends to be obtained.

[0072] When the rubber composition contains silica, it further preferably contains a silane coupling agent. The silane coupling agent is not particularly limited, and any silane coupling agent 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-triethoxysilylbutyl)tetrasulfide bis(4-trimethoxysilylbutyl) disulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, Thioether-based silanes such as 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylic acid monosulfide; mercapto-based silanes such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z manufactured by Momentive; ethylene Vinyl series such as triethoxysilane and vinyl trimethoxysilane; amino series such as 3-aminopropyl triethoxysilane and 3-aminopropyl trimethoxysilane; glycidoxy series such as γ-glycidoxypropyl triethoxysilane and γ-glycidoxypropyl trimethoxysilane; nitro series such as 3-nitropropyl trimethoxysilane and 3-nitropropyl triethoxysilane; chlorine series such as 3-chloropropyl trimethoxysilane and 3-chloropropyl triethoxysilane. As commercially available products, products of Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Dow Corning Toray Industries, Ltd., etc. can be used. They can be used alone or in combination of two or more.

[0073] In the rubber composition, the content of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more, relative to 100 parts by mass of silica. The upper limit of the content is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, further preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. When within the above range, a better effect tends to be obtained.

[0074] The above-mentioned rubber composition contains a nitrogen-containing compound. The nitrogen-containing compound is not particularly limited as long as it is a compound having nitrogen in its molecule. The nitrogen-containing compound may be used alone or in combination of two or more.

[0075] In the rubber composition, the content of the nitrogen-containing compound is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, and particularly preferably 33 parts by mass or more, relative to 100 parts by mass of carbon black. The upper limit of the content is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and further preferably 50 parts by mass or less. When within the above range, a better effect tends to be obtained.

[0076] From the viewpoint of obtaining a better effect, the nitrogen-containing compound preferably contains an isocyanate compound.

[0077] The mechanism of obtaining a better effect when an isocyanate compound is contained is not clear, but isocyanate has high reactivity with hydroxyl groups. Therefore, it is estimated that the affinity with the polymer is improved, the reinforcement and carbon black dispersibility are improved, and the overall performance of handling stability, wear resistance and low fuel consumption is improved.

[0078] As the isocyanate compound, there can be mentioned a compound having at least one isocyanate group. The compound having at least one isocyanate group can be mentioned a monofunctional isocyanate and a polyfunctional isocyanate. Among them, from the viewpoint of obtaining a better effect, a monofunctional isocyanate is preferred.

[0079] Examples of the monofunctional isocyanate include methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, octyl isocyanate, decyl isocyanate, octadecyl isocyanate, stearyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, benzyl isocyanate, p-chlorophenyl isocyanate, p-nitrophenyl isocyanate, (R)-(+)-α-methylbenzyl isocyanate, (R)-(+)-1-phenylethyl isocyanate, (S)-(-)-1-phenylethyl isocyanate, and p-toluenesulfonyl isocyanate. Among them, benzyl isocyanate and (R)-(+)-α-methylbenzyl isocyanate are preferred, and benzyl isocyanate is more preferred, from the viewpoint of obtaining a better effect.

[0080] Examples of the polyfunctional isocyanate include aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates.

[0081] Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4′-dimethylbiphenyl diisocyanate, 2,4,6-triisocyanatotoluene, 1,3,5-triisocyanatobenzene, 3,3′-dimethoxy-4,4′-biphenyl diisocyanate, 4,4′-diphenyl ether diisocyanate, and 4,4′,4″-triphenylmethane triisocyanate.

[0082] Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0083] Examples of the aromatic aliphatic polyisocyanate include ω,ω′-diisocyanate-1,3-dimethylbenzene and 1,4-tetramethylxylylene diisocyanate.

[0084] Examples of the alicyclic polyisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis(isocyanate cyclohexyl) and 1,4-bis(isocyanate methyl)cyclohexane.

[0085] In the rubber composition, the content of the isocyanate compound is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, and particularly preferably 33 parts by mass or more, relative to 100 parts by mass of carbon black. The upper limit of the content is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and further preferably 50 parts by mass or less. When within the above range, a better effect tends to be obtained. In addition, the content of the monofunctional isocyanate and the content of benzyl isocyanate are also preferably in the same range.

[0086] From the viewpoint of obtaining a better effect, the nitrogen-containing compound preferably contains a compound represented by the following formula (A). [Chemistry 1] (wherein, ring Q 1 It represents a group selected from halogen atoms, hydroxyl groups, amino groups, nitro groups, C1-6 Alkyl, C 1-6 Alkoxy and C 1-6 A benzene ring substituted with 1 to 3 groups in the group consisting of alkyl-carbonyl; Ring Q 2 It represents a group selected from halogen atoms, hydroxyl groups, amino groups, nitro groups, C 1-6 Alkyl, C 1-6 Alkoxy and C 1-6 An imidazole ring substituted with 1 to 2 groups consisting of an alkyl-carbonyl group.

[0087] As a ring Q 1 , preferably can be selected from halogen atoms, hydroxyl groups, amino groups, C 1-4 Alkyl, C 1-4 A benzene ring substituted with 1 to 3 groups selected from the group consisting of alkoxy and acetyl; more preferably, a halogen atom, C 1-4 Alkyl and C 1-4 A benzene ring substituted with 1 to 3 groups consisting of an alkoxy group.

[0088] As a ring Q 2 , preferably can be selected from halogen atoms, hydroxyl groups, amino groups, C 1-4 Alkyl, C 1-4 An imidazole ring substituted with 1 to 2 groups selected from the group consisting of alkoxy and acetyl; more preferably, an imidazole ring substituted with 1 to 2 groups selected from the group consisting of halogen atoms, amino groups and C 1-4 An imidazole ring substituted with 1 to 2 groups in the group consisting of alkyl; more preferably substituted with 1 to 2 C 1-4 Alkyl substituted imidazole ring. It should be noted that the bonding site to the carbonyl group on the imidazole ring may be any of the carbon atom and the nitrogen atom constituting the ring.

[0089] In the rubber composition, relative to 100 parts by mass of carbon black, the content of the compound shown in the above formula (A) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, and particularly preferably 33 parts by mass or more. The upper limit of the content is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and further preferably 50 parts by mass or less. When within the above range, a better effect tends to be obtained.

[0090] When carbon black is combined with the compound represented by the above formula (A), the amide bond of the compound represented by the formula (A) undergoes a hydrolysis reaction and breaks during the kneading process, and the resulting compound having an amino group is combined with the functional group on the surface of the carbon black. On the other hand, the carboxylic acid represented by the following formula (A1) produced as a result of the hydrolysis can be recovered by Soxhlet extraction of the vulcanized rubber. [Chemistry 2] (Ring Q 2 It represents a group selected from halogen atoms, hydroxyl groups, amino groups, nitro groups, C 1-6 Alkyl, C 1-6 Alkoxy and C 1-6 An imidazole ring substituted with 1 to 2 groups consisting of an alkyl-carbonyl group.

[0091] As a ring Q 2 , preferably can be selected from halogen atoms, hydroxyl groups, amino groups, C 1-4 Alkyl, C 1-4 An imidazole ring substituted with 1 to 2 groups selected from the group consisting of alkoxy and acetyl; more preferably, an imidazole ring substituted with 1 to 2 groups selected from the group consisting of halogen atoms, amino groups and C 1-4 An imidazole ring substituted with 1 to 2 groups in the group consisting of alkyl; more preferably substituted with 1 to 2 C 1-4 Alkyl-substituted imidazole ring. It should be noted that the bonding site to the carbonyl group on the imidazole ring may be any of the carbon atom and the nitrogen atom constituting the ring.

[0092] For the rubber composition after vulcanization, the amount of the compound represented by formula (A1) extracted when Soxhlet extraction is performed at 80°C for 72 hours using acetone as a solvent according to method A described in JIS K 6229:2015 "Determination (quantitative) of rubber-solvent extracts" is preferably 0.10 parts by mass or more, more preferably 0.20 parts by mass or more, further preferably 0.30 parts by mass or more, and particularly preferably 0.40 parts by mass or more, relative to 100 parts by mass of carbon black. In addition, the upper limit of the amount of the compound represented by formula (A1) is not particularly limited, but is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and further preferably 30 parts by mass or less.

[0093] In the rubber composition, from the viewpoint of obtaining a better effect, the regenerated carbon black is preferably obtained by previously surface-treating the regenerated carbon black with the nitrogen-containing compound (hereinafter also referred to as nitrogen-treated regenerated carbon black).

[0094] The mechanism of obtaining better effects in the case of nitrogen-treated regenerated carbon black is not clear, but by using nitrogen-treated regenerated carbon black that has been treated in advance, it is easy to cause the carbon black surface to react with nitrogen-containing compounds. Therefore, it is speculated that the affinity with the polymer is improved, the reinforcement and dispersibility of carbon black are improved, and the comprehensive performance of handling stability, wear resistance and low fuel consumption is improved.

[0095] The rubber composition may contain a plasticizer. In this specification, plasticizer refers to a material that imparts plasticity to a rubber component, and includes the concepts of a plasticizer that is liquid (liquid state) at room temperature (25°C) and a plasticizer that is solid at room temperature (25°C). Examples of plasticizers include: resin components, oils, liquid polymers, ester plasticizers, etc. These plasticizers may be derived from petroleum, biomass, or naphtha recycled from rubber products or non-rubber products. In addition, low molecular weight hydrocarbon components obtained by thermal decomposition and extraction of used tires and products containing various components may be used as plasticizers. These plasticizers may be used alone or in combination of two or more.

[0096] Specific examples of the plasticizer include oils, liquid polymers, resins, etc. These may be used alone or in combination of two or more.

[0097] As oil, for example, process oil, vegetable oil, animal oil, etc. can be cited. As process oil, paraffin-based process oil (mineral oil), naphthenic process oil, aromatic process oil, etc. can be cited. As specific examples of process oil, for example, MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), etc. can be cited. In addition, process oils with low content of polycyclic aromatic compounds (PCA) can also be used in environmental measures. As the low PCA content process oil, MES, TDAE, heavy naphthenic oil, etc. can be cited. In addition, from the perspective of life cycle assessment, oils refined from waste oil used in rubber mixers or engines and waste cooking oil used in restaurants can also be used.

[0098] 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, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia oil, peanut oil, grape seed oil, wood wax, etc. Further, as vegetable oils, refined oils (salad oils, etc.) obtained by refining the oils, ester exchange oils obtained by transesterifying the oils, solidified oils obtained by hydrogenating the oils, thermally polymerized oils obtained by thermally polymerizing the oils, oxidatively polymerized oils obtained by oxidizing the oils, and waste edible oils obtained by recovering oils used as edible oils, etc. It should be noted that vegetable oils can be liquid or solid at room temperature (25° C.). These vegetable oils can be used alone or in combination of two or more.

[0099] The vegetable oil of the present embodiment preferably contains acylglycerols, and more preferably contains triacylglycerols. It should be noted that, in the present specification, acylglycerols refer to compounds in which the hydroxyl group of glycerol forms an ester bond with a fatty acid. There are no particular limitations on the acylglycerols, and it can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerols can be monomers, dimers, or polymers of trimers or higher. It should be noted that acylglycerols of dimers or higher can be obtained by thermal polymerization, oxidative polymerization, etc. In addition, the acylglycerols can be liquid or solid at room temperature (25°C).

[0100] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, and the method can be performed by 1 For example, a rubber composition mixed with triacylglycerol is immersed in deuterated chloroform at room temperature (25°C) for 24 hours, and then the rubber composition is removed and then measured at room temperature. 1 H-NMR, when the signal of tetramethylsilane (TMS) was set to 0.00 ppm, signals were observed near 5.26 ppm, near 4.28 ppm, and near 4.15 ppm, and it is speculated that these signals are from the signals of hydrogen atoms bonded to the carbon atoms adjacent to the oxygen atoms of the ester group. It should be noted that "near" in this paragraph refers to the range of ±0.10 ppm.

[0101] The fatty acid is not particularly limited and may be an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0102] Among them, as the above-mentioned fatty acid, it is preferred to contain a fatty acid with few double bonds, i.e. a saturated fatty acid or a monounsaturated fatty acid, preferably oleic acid. As the vegetable oil containing such fatty acid, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid can be used, and a vegetable oil modified by transesterification can also be used. In addition, in order to manufacture the vegetable oil containing such fatty acid, plants can also be improved by variety improvement, genetic recombination, genome editing, etc.

[0103] As the oil, for example, commercially available products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Olisur Co., Ltd., H&R Co., Ltd., Toyokuni Oil Manufacturing Co., Ltd., Fuji Kosan Co., Ltd., Nissin Oillio Group Co., Ltd., etc. can be used.

[0104] As the above-mentioned liquid polymer, for example, there can be mentioned: a diene polymer (liquid rubber) that is liquid at 25°C, a liquid farnesene polymer, etc. As the liquid rubber, there can be mentioned: a liquid styrene-butadiene copolymer (liquid SBR), a liquid butadiene polymer (liquid BR), a liquid polyisoprene polymer (liquid IR), a liquid styrene isoprene copolymer (liquid SIR), a liquid styrene-butadiene styrene block copolymer (liquid SBS block polymer), a liquid styrene isoprene styrene block copolymer (liquid SIS block polymer), etc. Their ends or main chains can also be modified with polar groups. In addition, their hydrogenated products can also be used.

[0105] The liquid diene polymer preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 1.0×10 3 ~5.0×10 4 , more preferably 3.0×10 3 ~1.5×10 4 In addition, the lower limit or upper limit of Mw of the liquid diene polymer may be 4,500 or 8,500. In addition, in this specification, Mw of a liquid diene polymer is a polystyrene conversion value measured by gel permeation chromatography (GPC).

[0106] As the liquid diene polymer, for example, products produced by Sartomer Co., Ltd., Kuraray Co., Ltd., and the like can be used.

[0107] As the above-mentioned resin, as a tire compound, a commonly used resin can be used, which can be liquid or solid at room temperature (25°C). For example, aromatic vinyl polymers, coumarone-indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, acrylic resins, etc. can be mentioned. In addition, the resin can also be a hydrogenated resin (hydrogenated resin). They can be used alone or in combination of two or more. In addition, the resin itself can also be a resin obtained by copolymerizing monomer components from multiple sources. Among them, aromatic vinyl polymers, petroleum resins, terpene resins, and their hydrogenated resins are preferred.

[0108] When a resin that is solid at room temperature is used, the softening point of the resin is preferably 50° C. or higher, more preferably 55° C. or higher, further preferably 60° C. or higher, particularly preferably 85° C. or higher. Furthermore, it is preferably 160° C. or lower, more preferably 150° C. or lower, further preferably 140° C. or lower, and particularly preferably 100° C. or lower. Within the above range, better effects tend to be obtained. When the resin is liquid at room temperature, the softening point is preferably 20° C. or lower, preferably 10° C. or lower, and preferably 0° C. or lower. In the case of a hydrogenated resin, the same softening point as above is also preferred. It should be noted that the softening point of the above resin is the softening point specified in JIS K6220-1:2001, measured using a ring and ball softening point measuring device, and is the temperature when a ball falls.

[0109] The aromatic vinyl polymer is a polymer containing an aromatic vinyl monomer as a structural unit, and examples thereof include resins obtained by polymerizing α-methylstyrene and / or styrene, and specifically include homopolymers of styrene (styrene resins), homopolymers of α-methylstyrene (α-methylstyrene resins), copolymers of α-methylstyrene and styrene, and copolymers of styrene and other monomers.

[0110] The coumarone-indene resin is a resin containing coumarone and indene as main monomer components constituting the resin skeleton (main chain). Examples of monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, and the like.

[0111] The coumarone resin is a resin containing coumarone as a main monomer component constituting the resin skeleton (main chain).

[0112] The indene resin is a resin containing indene as a main monomer component constituting the resin skeleton (main chain).

[0113] As the phenolic resin, for example, known resins such as polymers obtained by reacting phenol with aldehydes such as formaldehyde, acetaldehyde, and furfural using an acid or base catalyst can be used. Among them, resins obtained by reacting using an acid catalyst (such as novolac phenolic resins) are preferred.

[0114] Examples of the rosin resin include rosin-based resins represented by natural rosin, polymerized rosin, modified rosin, ester compounds thereof, and hydrogenated products thereof.

[0115] Examples of the petroleum resin include C5 resins, C9 resins, C5 / C9 resins, dicyclopentadiene (DCPD) resins, C9 / DCPD resins, and hydrogenated products thereof, among which DCPD resins, hydrogenated DCPD resins, C9 / DCPD resins, and C9 / hydrogenated DCPD resins are preferred.

[0116] The above-mentioned terpene resin is a polymer containing terpene as a structural unit. For example, polyterpene resins obtained by polymerizing terpene compounds, aromatic modified terpene resins obtained by polymerizing terpene compounds and aromatic compounds, etc. can be mentioned. As aromatic modified terpene resins, terpene phenolic resins using terpene compounds and phenolic compounds as raw materials, terpene styrene resins using terpene compounds and styrene compounds as raw materials, and terpene phenol styrene resins using terpene compounds, phenolic compounds and styrene compounds as raw materials can also be used. It should be noted that as terpene compounds, α-pinene, β-pinene, etc. can be mentioned, as phenolic compounds, phenol, bisphenol A, etc. can be mentioned, and as aromatic compounds, styrene compounds (styrene, α-methylstyrene, etc.) can be mentioned. Among them, aromatic modified terpene resins are preferred.

[0117] The acrylic resin is a polymer containing an acrylic monomer as a structural unit. For example, styrene acrylic resins such as styrene acrylic resins obtained by copolymerizing an aromatic vinyl monomer component and an acrylic monomer component having a carboxyl group can be cited. Among them, solvent-free carboxyl-containing styrene acrylic resins can be preferably used.

[0118] As the above-mentioned resin, for example, products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical, Exxon Mobil, Kraton, Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0119] As the plasticizer, from the viewpoint of sustainable development, it is preferred to use a plant-derived plasticizer such as the plant-derived oil and farnesene polymer.

[0120] Farnesene polymers are polymers obtained by polymerizing farnesene, and have structural units based on farnesene. Farnesene has isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene), and (E)-β-farnesene having the following structure is preferred. [Chemistry 3]

[0121] Farnesene polymers may be homopolymers of farnesene (farnesene homopolymers), or copolymers of farnesene and vinyl monomers (farnesene-vinyl monomer copolymers). They may be used alone or in combination of two or more. Among them, copolymers of farnesene and vinyl monomers are preferred.

[0122] As the vinyl monomer, there can be mentioned: styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, dimethylstyrene, vinylnaphthalene, vinyltoluene, vinylpyridine, diphenylethylene, aromatic vinyl compounds such as diphenylethylene containing tertiary amino groups, butadiene, conjugated diene compounds such as isoprene, etc. They can be used alone or in combination of two or more. Among them, butadiene is preferred. That is, as the farnesene-vinyl monomer copolymer, a copolymer of farnesene and butadiene (farnesene-butadiene copolymer) is preferred.

[0123] In the farnesene-vinyl monomer copolymer, the copolymerization ratio of farnesene to vinyl monomer (farnesene / vinyl monomer) is preferably 40 / 60 to 90 / 10 on a mass basis.

[0124] The farnesene polymer may preferably have a weight average molecular weight (Mw) of 3,000 or more and 300,000 or less. The Mw of the farnesene polymer is preferably 8,000 or more, more preferably 10,000 or more, and preferably 100,000 or less, more preferably 60,000 or less, and further preferably 50,000 or less. When it is within the above range, a better effect tends to be obtained.

[0125] The farnesene polymer may be in a liquid state or a solid state at room temperature (25° C.), and among them, a liquid farnesene polymer that is in a liquid state at room temperature (25° C.) is preferred.

[0126] When the rubber composition contains a plasticizer, the content of the plasticizer (the total amount of the plasticizer) is preferably 20 parts by mass or more, more preferably 35 parts by mass or more, and more preferably 40 parts by mass or more relative to 100 parts by mass of the rubber component. The upper limit is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and more preferably 50 parts by mass or less. When within the above range, a better effect is tended to be obtained. It should be noted that the content of the plasticizer also includes the amount of oil and resin contained in the oil-extended rubber and the resin-filled rubber.

[0127] In the rubber composition, the content of the solid plasticizer in a solid state at room temperature (25° C.) is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and further preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber component. The upper limit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and further preferably 30 parts by mass or less. When within the above range, a better effect tends to be obtained. In addition, the content of the above-mentioned resin in a solid state at room temperature (25° C.) is also preferably in the same range.

[0128] In the rubber composition, the content of the liquid plasticizer in a liquid state at room temperature (25°C) is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and further preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber component. The upper limit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and further preferably 30 parts by mass or less. When within the above range, a better effect tends to be obtained. It should be noted that the content of the liquid plasticizer also includes the amount of oil contained in the oil-filled rubber and the amount of liquid resin in the resin-filled rubber. The content of the oil that is liquid at room temperature (25° C.) is also preferably in the same range.

[0129] From the viewpoint of crack resistance, ozone resistance, and the like, the rubber composition preferably contains an antioxidant.

[0130] The antioxidant is not particularly limited, but examples thereof include: naphthylamine antioxidants such as phenyl-α-naphthylamine; diphenylamine antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl-p-phenylenediamine (D p-phenylenediamine antioxidants such as TPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bisphenol antioxidants such as tetrakis-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane, triphenol antioxidants or polyphenol antioxidants. Among them, p-phenylenediamine antioxidants and quinoline antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., Flexsys Corporation, and the like can be used.

[0131] In the rubber composition, the content of the antioxidant is preferably 0.2 parts by mass or more, more preferably 0.7 parts by mass or more, and further preferably 1.0 parts by mass or more, relative to 100 parts by mass of the rubber component. The content is preferably 10.0 parts by mass or less, and more preferably 6.0 parts by mass or less.

[0132] The rubber composition preferably contains stearic acid. In the rubber composition, the content of stearic acid is preferably 0.5 parts by mass or more, more preferably 2.0 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the rubber component.

[0133] As stearic acid, conventionally known stearic acid can be used. For example, products of NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc. can be used.

[0134] The rubber composition preferably contains zinc oxide. In the rubber composition, the content of zinc oxide is preferably 0.5 parts by mass or more, more preferably 2.0 parts by mass or more, and preferably 6.0 parts by mass or less, more preferably 4.0 parts by mass or less, based on 100 parts by mass of the rubber component.

[0135] As zinc oxide, conventionally known zinc oxide can be used, and for example, products of Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Shiramizu Techno Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., and the like can be used.

[0136] The above-mentioned rubber composition may contain wax. In the rubber composition, the wax content is preferably 0.5 parts by mass or more, more preferably 1.2 parts by mass or more, and is preferably 8.0 parts by mass or less, more preferably 5.0 parts by mass or less, based on 100 parts by mass of the rubber component.

[0137] The wax is not particularly limited, and waxes commonly used in the tire industry can be preferably used. For example, petroleum waxes, mineral waxes, synthetic waxes, plant-derived waxes, etc. Among them, petroleum waxes and plant-derived waxes are preferred, and petroleum waxes are more preferred. As plant-derived waxes, for example, rice bran wax, carnauba wax, candelilla wax, etc. As petroleum waxes, for example, paraffin wax, microcrystalline wax, and selected special waxes thereof, etc., preferably paraffin wax. It should be noted that the wax of the present embodiment does not contain stearic acid. Waxes can use commercial products of Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seira Co., Ltd., Paramelt Co., Ltd., etc., for example. These waxes can be used alone or in combination of two or more.

[0138] It is preferred that sulfur be blended into the rubber composition in order to form appropriate crosslinks in the polymer chains and impart good performance.

[0139] In the rubber composition, the sulfur content is preferably 1.0 parts by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2.0 parts by mass or more, relative to 100 parts by mass of the rubber component. The sulfur content is preferably 7.0 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 4.0 parts by mass or less.

[0140] Sulfur includes powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. As commercially available products, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexsys Co., Ltd., Nippon Dry Industry Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used. These can be used alone or in combination of two or more.

[0141] The rubber composition preferably contains a vulcanization accelerator. In the rubber composition, the content of the vulcanization accelerator is not particularly limited and can be freely determined according to the desired vulcanization speed and crosslinking density, but is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and further preferably 0.5 parts by mass or more relative to 100 parts by mass of the rubber component. The upper limit is preferably 8.0 parts by mass or less, more preferably 5.0 parts by mass or less, and further preferably 4.0 parts by mass or less.

[0142] There is no particular limitation on the type of vulcanization accelerator, and commonly used vulcanization accelerators can be used. Examples of the vulcanization accelerator include benzothiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazole disulfide, and N-cyclohexyl-2-benzothiazole sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-o-tolylguanidine, and o-tolylbiguanide. They can be used alone or in combination of two or more. Among them, sulfenamide-based, guanidine-based, and benzothiazole-based vulcanization accelerators are preferred.

[0143] In addition to the above components, the rubber composition may also contain appropriately compounding agents commonly used in the tire industry, such as a mold release agent.

[0144] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining the above-mentioned compound from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through the following process can be converted, and the process is a methanation process for synthesizing methane from carbon dioxide.

[0145] The above rubber composition is used for tire components. In addition to the above components, the rubber composition may also contain appropriately compounding agents commonly used in the tire industry, such as a mold release agent.

[0146] The rubber composition can be produced, for example, by a method in which the above-mentioned components are kneaded using a rubber kneading device such as an open roll mill or a Banbury mixer, and then vulcanized.

[0147] As a kneading condition, in the basic kneading process of kneading additives other than the crosslinking agent (vulcanizing agent) and the vulcanization accelerator, the kneading temperature is preferably 100°C or more, more preferably 120°C or more, and preferably 180°C or less, more preferably 170°C or less. In the final kneading process of kneading the vulcanizing agent and the vulcanization accelerator, the kneading temperature is preferably 80°C or more, and preferably 120°C or less, more preferably 110°C or less. In addition, the composition kneaded with the vulcanizing agent and the vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. As the vulcanization temperature, it is preferably 140°C or more, more preferably 150°C or more, and preferably 190°C or less, more preferably 185°C or less.

[0148] The rubber composition can be applied to tire components (as a rubber composition for tires) such as tread cap, sidewall, tread base, base tread, lap joint, bead apex strip, buffer layer insulation rubber, carcass cord covering rubber, isolation layer, bead chafer, inner liner, sidewall reinforcement layer of run-flat tire, etc. Among them, from the viewpoint of obtaining better effects, the tire components are preferably tire internal components. It should be noted that, in this specification, the tire internal components refer to the components other than the tread running surface that contacts the road surface during driving (carcass ply, tread base, buffer layer, sidewall, lap apex, bead apex, etc.), and the sidewall and tread base are particularly preferred.

[0149] The tire is manufactured by a conventional method using the rubber composition. That is, the composition mixed with various additives can be extruded and processed in the shape of various tire components such as sidewalls in an unvulcanized stage as needed, molded in a tire molding machine by a conventional method, and bonded together with other tire components. After forming an unvulcanized tire, it is heated and pressurized in a vulcanizer to manufacture the tire.

[0150] The tire is not particularly limited, and examples thereof include pneumatic tires, solid tires, airless tires, etc. Among them, pneumatic tires are preferred.

[0151] The above tires can be suitably used as tires for passenger cars, large passenger cars, large SUVs, truck and bus tires, two-wheeled vehicle tires, racing tires, winter tires (studless tires, snow tires, studded tires), all-season tires, run-flat tires, aircraft tires, mining tires, etc.

[0152] The tire has tire components made from the rubber composition. In the tire, the content A (parts by mass) of the carbon black relative to 100 parts by mass of the rubber component of the rubber composition, the nitrogen content B (parts by mass) relative to 100 parts by mass of the rubber component of the rubber composition, and the maximum thickness C (mm) of the tire component satisfy the following formula (1): (1)A×B / C>0.5. A×B / C is preferably 1.0 or more, more preferably 1.6 or more, further preferably 2.5 or more, and particularly preferably 3.0 or more. The upper limit of A×B / C is preferably 8.0 or less, more preferably 5.0 or less, and further preferably 4.0 or less. When within the above range, better effects tend to be obtained.

[0153] In the rubber composition, the nitrogen content B (nitrogen atom content B) is 0.20 parts by mass or more relative to 100 parts by mass of the rubber component. B is preferably 0.25 parts by mass or more, more preferably 0.28 parts by mass or more, and further preferably 0.30 parts by mass or more. The upper limit of B is preferably 0.50 or less, more preferably 0.40 or less, and further preferably 0.33 or less. When within the above range, a better effect tends to be obtained. In this specification, the nitrogen content B relative to 100 parts by mass of the rubber component refers to the content of nitrogen atoms in the nitrogen-containing compound contained in the rubber composition relative to 100 parts by mass of the rubber component in the rubber composition. It should be noted that the nitrogen content B does not include the amount of nitrogen atoms in the modified rubber modified with a nitrogen-containing modifier and the amount of nitrogen atoms in fillers such as the nitrogen-treated regenerated carbon black. That is, for example, in the case of a rubber composition consisting of 100 parts by mass of a modified rubber modified with a nitrogen-containing modifier, 10 parts by mass of conventional carbon black, 10 parts by mass of the above-mentioned nitrogen-treated regenerated carbon black, 1 part by mass of the above-mentioned nitrogen-containing compound, 2 parts by mass of stearic acid, 2 parts by mass of zinc oxide, 2 parts by mass of sulfur, 1 part by mass of a nitrogen-containing antioxidant, and 0.5 parts by mass of a nitrogen-containing vulcanization accelerator, the nitrogen content B relative to 100 parts by mass of the rubber component is the total content of the nitrogen content (parts by mass) in the above-mentioned nitrogen-containing compound, the nitrogen content (parts by mass) in the above-mentioned nitrogen-containing antioxidant, and the nitrogen content (parts by mass) in the above-mentioned nitrogen-containing vulcanization accelerator relative to 100 parts by mass of the rubber component.

[0154] In the above tire, the maximum thickness C of the tire component is preferably 8.0 mm or less, more preferably 6.0 mm or less, further preferably 5.0 mm or less, and particularly preferably 4.0 mm or less. The lower limit of the thickness C of the tire component is preferably 0.5 mm or more, more preferably 0.8 mm or more, further preferably 1.0 mm or more, and when it is within the above range, the effect tends to be well obtained.

[0155] It should be noted that in this specification, the maximum thickness C of a tire component refers to the maximum value of the thickness of each tire component (sidewall, tread base, etc.). The thickness at each point on the surface of each tire component is the straight-line distance measured along the normal line of the surface of each tire component at that point, and the maximum thickness C of each tire component is the maximum value of the thickness at each point.

[0156] In the above tire, the maximum thickness Ts (mm) of the sidewall is preferably 8.0 mm or less, more preferably 6.0 mm or less, further preferably 5.0 mm or less, and particularly preferably 4.0 mm or less. The lower limit of Ts is preferably 2.0 mm or more, more preferably 2.5 mm or more, further preferably 3.0 mm or more, and when it is within the above range, the effect tends to be well obtained.

[0157] It should be noted that in this specification, the maximum thickness Ts of the sidewall refers to the maximum value of the thickness of the sidewall. The thickness at each point on the sidewall surface is the straight-line distance measured along the normal line of the sidewall surface at that point, and the maximum thickness Ts of the sidewall is the maximum value of the thickness at each point.

[0158] In the tire, the ratio (A / C) of the carbon black content A (parts by mass) per 100 parts by mass of the rubber component of the rubber composition to the maximum thickness C (mm) of the tire member is preferably greater than 21.0. A / C is preferably 22.0 or more, more preferably 24.0 or more, and further preferably 25.0 or more. In addition, the lower limit of A / C is preferably 50.0 or less, more preferably 40.0 or less, and further preferably 35.0 or less. When within the above range, a better effect tends to be obtained.

[0159] When A / C is greater than the specified value, especially greater than 21.0, the mechanism for obtaining a better effect is not clear, but a sufficient amount of carbon black can be mixed in large quantities relative to the thickness of the tire components to improve the reinforcement. Therefore, it is estimated that the comprehensive performance of handling stability, wear resistance and low fuel consumption is improved.

[0160] In the tire, the ratio (B / C) of the nitrogen content B (parts by mass) to the maximum thickness C (mm) of the tire member relative to 100 parts by mass of the rubber component of the rubber composition is preferably less than 0.15. B / C is preferably 0.14 or less, more preferably 0.13 or less, and further preferably 0.12 or less. In addition, the lower limit of B / C is preferably 0.01 or more, more preferably 0.05 or more, and further preferably 0.08 or more. When within the above range, a better effect tends to be obtained.

[0161] When B / C is less than the specified value, especially less than 0.15, the mechanism for obtaining a better effect is unclear, but the balance between the thickness of the tire components and the nitrogen content becomes good, so it is estimated that the overall performance of steering stability, wear resistance and low fuel consumption is improved.

[0162] In the above tire, the groove depth D (mm) of the circumferential groove formed on the tread is preferably 5.5 mm or more, more preferably 5.8 mm or more, and further preferably 6.0 mm or more, and is preferably 8.5 mm or less, more preferably 8.0 mm or less, and further preferably 7.5 mm or less. When it is within the above range, better effects tend to be obtained.

[0163] The mechanism for obtaining a better effect when the groove depth D of the circumferential groove formed on the tread is adjusted to a specified range is not clear, but by adjusting the groove depth, the lightweight is adjusted in a well-balanced manner while maintaining the elongation, and as a result, it is speculated that the overall performance of handling stability, wear resistance and low fuel consumption is improved.

[0164] It should be noted that, in this specification, the groove depth D of the circumferential groove refers to the distance from the extended surface forming the contact surface of the outermost surface of the tread to the deepest groove bottom, measured along the normal line of the surface formed by extending the surface forming the contact surface, and refers to the maximum distance among the groove depths of the circumferential grooves.

[0165] In the tire, the ratio (A / D) of the carbon black content A (parts by mass) per 100 parts by mass of the rubber component of the rubber composition to the groove depth D (mm) of the circumferential groove formed in the tread is preferably 3.0 or more and 10.0 or less. A / D is preferably 4.5 or more, more preferably 5.0 or more, and further preferably 5.5 or more. In addition, the upper limit of A / D is preferably 9.0 or less, more preferably 8.5 or less, and further preferably 8.0 or less. When within the above range, a better effect tends to be obtained.

[0166] The mechanism for achieving better results when A / D is adjusted to the specified range is not clear, but by adjusting the groove depth, it is possible to adjust the weight reduction and maintain the elongation in a well-balanced manner, and at the same time, by containing a sufficient amount of carbon, the affinity with the polymer is improved, and the reinforcement and fuel efficiency can be improved. Therefore, it is estimated that the comprehensive performance of handling stability, wear resistance and fuel efficiency is improved.

[0167] In the tire, the ratio (B / D) of the nitrogen content B (parts by mass) per 100 parts by mass of the rubber component of the rubber composition to the groove depth D (mm) of the circumferential groove formed in the tread is preferably 0.03 or more and 0.08 or less. B / D is preferably 0.04 or more, more preferably 0.05 or more. In addition, the upper limit of B / D is preferably 0.08 or less, more preferably 0.07 or less, and further preferably 0.06 or less. When within the above range, a better effect tends to be obtained.

[0168] The mechanism for achieving better effects when B / D is adjusted to the specified range is not clear, but by adjusting the groove depth, it is possible to adjust the weight reduction and maintain the elongation in a well-balanced manner, and by containing a sufficient amount of nitrogen atoms, the affinity with the polymer is improved, which can improve reinforcement and fuel efficiency. Therefore, it is estimated that the comprehensive performance of handling stability, wear resistance and fuel efficiency is improved.

[0169] In this specification, the thickness and other dimensions are measured with the tire bead portion aligned with the standard rim width. During the measurement, the tire is cut out in the tire radial direction and the sample is fixed with the bead ends on both sides aligned with the standard rim width.

[0170] In this specification, unless otherwise specified, the dimensions of each part of the tire are the values ​​measured under normal conditions. "Normal condition" means that the tire is mounted on a normal rim and filled with a normal internal pressure, and is in a no-load state. Here, "normal rim" refers to the rim specified for each tire in the standard system including tire-based standards. For example, if it is JATMA (Japan Automobile Tire Association), it refers to the standard rim of applicable size recorded in the "JATMA Yearbook"; if it is ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "Measuring Rim" recorded in the "Standards Manual"; if it is TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" recorded in the "YEAR BOOK". Rim)", and refer to them in the order of JATMA, ETRTO, and TRA. If there is an applicable size during the reference, the standard shall be followed. Also, in the case of a tire not specified in the standard, it refers to a rim that can be assembled with a rim and can maintain the internal pressure, that is, a rim with the smallest diameter and the narrowest rim width among the rims that will not cause air leakage between the rim and the tire. In addition, "normal internal pressure" refers to the air pressure specified for each tire in each standard in a standard system that includes tire-based standards. In the case of JATMA, it refers to the "maximum air pressure"; in the case of ETRTO, it refers to the "inflation pressure (INFLATION PRESSURE)"; in the case of TRA, it refers to the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES (TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES The maximum value recorded in "Regular Pressures (Regular Internal Pressures)" is used, and is referenced in the order of JATMA, ETRTO, and TRA. If there is an applicable size, the standard is used. In the case of tires not specified in the standard, it refers to the regular internal pressure (of which 250 kPa or more) of other tire sizes (tires specified in the standard) that record the above-mentioned regular rim as the standard rim. It should be noted that when multiple regular internal pressures of 250 kPa or more are recorded, it refers to the minimum value among them.

[0171] Hereinafter, an example of the above-mentioned tire will be described using drawings, but the present invention is not limited to this embodiment.

[0172] Figure 1In the figure, the up-down direction is the radial direction of the tire 2, the left-right direction is the axial direction of the tire 2, and the direction perpendicular to the paper surface is the circumferential direction of the tire 2. The tire 2 is bilaterally symmetrical. The tread 4 includes a cap layer 30 (tread running surface) and a base layer 28 (tread base).

[0173] It should be noted that in Figure 1 , an example of a two-layer structure tread 4 composed of a cap layer 30 and a base layer 28 is shown, but a single-layer structure tread or a tread having a structure of three or more layers may also be used.

[0174] In the tire 2, each sidewall 6 extends slightly inward in the radial direction from the end of the tread 4. The radially outer portion of the sidewall 6 is joined to the tread 4. The radially inner portion of the sidewall 6 is joined to the lap portion 10. The sidewall 6 can prevent damage to the carcass 14.

[0175] Figure 1 In the tire 2, the sidewall 6 is composed of the above-mentioned rubber composition. The sidewall 6 is composed of a rubber composition containing a rubber component and carbon black containing regenerated carbon black, the rubber composition contains a nitrogen-containing compound, the nitrogen content is 0.20 parts by mass or more relative to 100 parts by mass of the rubber component, and the carbon black content A, the nitrogen content B, and the maximum thickness Ts (mm) of the sidewall 6 relative to 100 parts by mass of the rubber component satisfy the formula (1) "A×B / C>0.5".

[0176] Figure 1 Each tread wing 8 is located between the tread 4 and the sidewall 6. The tread wing 8 is joined to the tread 4 and the sidewall 6, respectively.

[0177] Each clinch portion 10 is located slightly inward of the sidewall 6 in the radial direction and has at least one portion in contact with the rim.

[0178] The carcass 14 includes a carcass ply 36. In the tire 2, the carcass 14 is composed of a single carcass ply 36, but may be composed of two or more layers.

[0179] In the tire 2, the carcass ply 36 is laid between the bead cores 32 on both sides and along the tread 4 and the sidewall 6. The carcass ply 36 is folded from the axial inside to the outside around each bead core 32. By the folding, a main body portion 36a and a pair of folded portions 36b are formed in the carcass ply 36. That is, the carcass ply 36 includes a main body portion 36a and a pair of folded portions 36b.

[0180] Each bead core 32 includes a bead apex strip 34 extending radially outward from the bead core 32. The bead core 32 is annular and preferably includes a wound inextensible wire. The bead apex strip 34 tapers radially outward.

[0181] Although not shown, the carcass ply 36 is preferably composed of a plurality of parallel cords and a topping rubber. The absolute value of the angle formed by each cord relative to the equatorial plane CL is preferably 75° to 90°. In other words, the carcass 14 preferably has a meridian structure.

[0182] Figure 1 The belt layer 16 is located radially inward of the tread 4. The belt layer 16 is stacked with the carcass 14. The belt layer 16 reinforces the carcass 14. Figure 1 In the tire 2, the belt layer 16 is composed of an inner layer 38 and an outer layer 40. Figure 1 It can be seen that in the axial direction, the width of the inner layer 38 is preferably slightly wider than the width of the outer layer 40 . In the tire 2 , the axial width of the belt layer 16 is preferably 0.6 times or more, and preferably 0.9 times or less, the cross-sectional width of the tire 2 .

[0183] It is preferable that the inner layer 38 and the outer layer 40 are respectively composed of a plurality of parallel single-wire steel cords (steel monofilaments) and a topping rubber (covering rubber). In other words, the belt layer 16 includes a plurality of parallel steel monofilaments.

[0184] Figure 1 The band layer 18 is located radially outside the belt layer 16. In the axial direction, the band layer 18 has the same width as the width of the belt layer 16. The band layer 18 may have a width greater than the width of the belt layer 16.

[0185] Although not shown, the belt layer 18 is preferably composed of cords and topping rubber. The cords are wound in a spiral shape. The belt layer 18 has a so-called annular (seamless) structure. The cords substantially extend in the circumferential direction. The angle of the cords relative to the circumferential direction is preferably less than 5°, and more preferably less than 2°. Since the belt layer 16 is constrained by the cords, the detachment of the belt layer 16 can be suppressed.

[0186] Figure 1 The belt layer 16 and the band layer 18 constitute a reinforcing layer. The reinforcing layer may also be constituted by only the belt layer 16.

[0187] Figure 2 yes Figure 1 An enlarged view of the vicinity of tread 4. Figure 2 The tire is a tire 2 having grooves 26 on the tire equatorial plane (CL).

[0188] Figure 2 , reference numeral P is a point on the sidewall surface 46. T is the thickness of the sidewall 6 at the point P. The thickness T is measured along the normal to the sidewall surface 46 at the point P. The maximum thickness Ts of the sidewall 6 is the maximum dimension among the thicknesses of the sidewall 6 at each point on the sidewall surface 46.

[0189] The inner liner 20 is located inside the carcass 14. The inner liner 20 is bonded to the inner surface of the carcass 14. A typical base rubber of the inner liner 20 is butyl rubber or halogenated butyl rubber. The inner liner 20 maintains the internal pressure of the tire 2.

[0190] Each chafer 22 is located near the bead 12. In this embodiment, the chafer 22 is preferably composed of cloth and rubber impregnated in the cloth. The chafer 22 may be integrated with the clinch portion 10.

[0191] In the tire 2, the tread 4 has main grooves 42 as the grooves 26. Figure 1 As shown in FIG. 1 , the tread 4 is engraved with a plurality of, specifically, three main grooves 42. These main grooves 42 are arranged at intervals in the axial direction. By engraving three main grooves 42 on the tread 4, four patterns 44 (rib-type patterns) extending in the circumferential direction are formed. That is, the main grooves 42 are between the patterns 44.

[0192] Each main groove 42 extends in the circumferential direction. The main groove 42 is continuous in the circumferential direction without interruption. The main groove 42 promotes the discharge of water between the road surface and the tire 2, for example, on rainy days. Therefore, even if the road surface is slippery, the tire 2 can fully contact the road surface. Figure 2 D represents the groove depth of the circumferential main groove 42 formed in the tread 4 .

[0193] In the tire 2, regarding the carbon black content A relative to 100 parts by mass of the rubber component of the sidewall 6, the nitrogen content B relative to 100 parts by mass of the rubber component of the sidewall 6, the maximum thickness C (mm) of the sidewall 6, and the groove depth D of the circumferential groove formed on the tread, it is preferred that A / C, B / C, A / D, B / D, C, and D are within the aforementioned ranges. Example

[0194] Hereinafter, examples (embodiments) considered to be preferable when implementing the present invention will be described, but the scope of the present disclosure is not limited to the embodiments.

[0195] Hereinafter, various chemical substances used in the manufacture of tires will be collectively described. It should be noted that the chemical substances are purified according to conventional methods as required. NR: TSR20 Carbon black: N660 manufactured by Asahi Carbon Co., Ltd. (average primary particle size: 66 nm) Regenerated carbon black 1: Commercially available product (manufactured by Klean Industries, average primary particle size: 35 nm) Regenerated carbon black 2: The above-mentioned regenerated carbon black 1 is dispersed in dehydrated toluene, and benzyl isocyanate (nitrogen-containing compound 2) is further added to react to obtain a regenerated carbon black Nitrogen-containing compound 1: the compound shown below (described in Japanese Patent Application Laid-Open No. 2020-70302) [Chemistry 4] Nitrogen-containing compound 2: Benzyl isocyanate (manufactured by Tokyo Chemical Industry) Stearic acid: Stearic acid "Tsubaki" manufactured by NOF Corporation Zinc oxide: Zinc oxide No. 2 manufactured by Mitsui Mining and Smelting Co., Ltd. Antioxidant: NOCRAC 224 (2,2,4-trimethyl-1,2-dihydroquinoline polymer) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator: NOCCELLER CZ (N-cyclohexyl-2-benzothiazole sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0196] <Production of test tires> According to the compounding contents shown in each table, materials other than sulfur and the vulcanization accelerator were kneaded at 150° C. for 5 minutes using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded product. Sulfur and a vulcanization accelerator were added to the kneaded product, and the mixture was kneaded at 80° C. for 5 minutes using an open roll mill to obtain an unvulcanized rubber composition. The unvulcanized rubber composition was molded into a sidewall shape and bonded together with other tire components on a tire molding machine to form an unvulcanized tire, which was vulcanized at 170° C. for 10 minutes to produce a test tire (size 205 / 70R15, passenger car tire).

[0197] Test tires were obtained by changing the compositions of the formulations and specifications according to the respective tables, and the results calculated by the following evaluation methods are shown in the respective tables. In addition, the reference comparative example is as follows. Table 1: Comparative Example 1-1 Table 2: Comparative Example 2-1 Table 3: Comparative Example 3-1

[0198] <Handling stability> The test tires were mounted on the vehicle and the control stability was evaluated on a five-point scale (maximum 5 points) while driving on the test route. The evaluation was performed by 20 test drivers, and the total value was expressed as an index with the evaluation standard being 100. The larger the index, the higher the control stability, indicating that the handling stability is better.

[0199] <Abrasion resistance> The test tires were mounted on a vehicle, and the tread groove depth was measured after a driving distance of 8,000 km. Then, the travel distance when the groove depth decreases by 1 mm was calculated and expressed as an index according to the following formula. A larger value indicates better wear resistance. (Abrasion resistance index) = (travel distance when the groove depth of each ratio is reduced by 1 mm) / (travel distance when the groove depth of the reference comparative example is reduced by 1 mm) × 100

[0200] <Low fuel consumption> The rolling resistance of the test tire when running at an internal pressure (230 kPa) and a speed (80 km / h) was measured using a rolling resistance tester, and the result was expressed as an index with the reference comparative example being 100. A larger value indicates better fuel economy.

[0201] [Table 1]

[0202] [Table 2]

[0203] [Table 3]

[0204] The present invention (1) is a tire comprising tire components composed of the following rubber composition, wherein the rubber composition contains a rubber component and carbon black including regenerated carbon black, wherein: The rubber composition contains a nitrogen-containing compound, The nitrogen content is 0.20 parts by mass or more relative to 100 parts by mass of the rubber component. The carbon black content A (parts by mass), the nitrogen content B (parts by mass), and the maximum thickness C (mm) of the tire component relative to 100 parts by mass of the rubber component satisfy the following formula (1): (1)A×B / C>0.5.

[0205] The present invention (2) is the tire according to the present invention (1), wherein the content A (parts by mass) of the carbon black is 30 parts by mass or more per 100 parts by mass of the rubber component.

[0206] The present invention (3) is the tire according to the present invention (1) or (2), wherein the nitrogen-containing compound contains an isocyanate compound.

[0207] The present invention (4) is a tire in combination with any one of the present inventions (1) to (3) wherein the average primary particle size of the carbon black is 30 nm or more and 60 nm or less.

[0208] The present invention (5) is a tire in combination with any one of the present inventions (1) to (4) wherein the regenerated carbon black is obtained by preliminarily surface-treating the regenerated carbon black with the nitrogen-containing compound.

[0209] The present invention (6) is a tire of any combination of any one of the present inventions (1) to (5), wherein the ratio (A / C) of the content A (parts by mass) of the above-mentioned carbon black relative to 100 parts by mass of the above-mentioned rubber component to the maximum thickness C (mm) of the above-mentioned tire components is greater than 21.0.

[0210] The present invention (7) is a tire of any combination of any one of the present inventions (1) to (6), wherein the ratio (B / C) of the nitrogen content B (parts by mass) relative to 100 parts by mass of the rubber component to the maximum thickness C (mm) of the tire component is less than 0.15.

[0211] The present invention (8) is a tire in combination with any one of the present inventions (1) to (7) wherein the groove depth D of the circumferential groove formed in the tread is 5.5 mm or more and 8.5 mm or less.

[0212] The present invention (9) is a tire described in the present invention (8) in which the ratio (A / D) of the content A (parts by mass) of the above-mentioned carbon black relative to 100 parts by mass of the above-mentioned rubber component to the groove depth D (mm) of the circumferential groove formed in the above-mentioned tread is greater than 3.0 and less than 9.0.

[0213] The present invention (10) is a tire described in the present invention (8) or (9), wherein the ratio (B / D) of the above-mentioned nitrogen content B (parts by mass) relative to 100 parts by mass of the above-mentioned rubber component to the groove depth D (mm) of the circumferential groove formed in the above-mentioned tread is greater than 0.04 and less than 0.08.

Claims

1. A tire comprising tire components composed of the following rubber composition, wherein the rubber composition contains a rubber component and carbon black containing regenerated carbon black, The rubber composition contains a nitrogen-containing compound, The nitrogen content is 0.20 parts by mass or more relative to 100 parts by mass of the rubber component. The carbon black content A, the nitrogen content B, and the maximum thickness C of the tire component relative to 100 parts by mass of the rubber component satisfy the following formula (1): (1) A×B / C>0.5, In the above formula, A and B are parts by mass, and C is mm.

2. The tire according to claim 1, wherein: The carbon black content A is 30 parts by mass or more relative to 100 parts by mass of the rubber component.

3. The tire according to claim 1, wherein: The content of the regenerated carbon black is 5 parts by mass or more and 150 parts by mass or less relative to 100 parts by mass of the rubber component.

4. The tire according to claim 1, wherein: The content of the regenerated carbon black in 100% by mass of the carbon black is 50% by mass or more and 100% by mass or less.

5. The tire according to claim 1, wherein: The nitrogen-containing compound contains an isocyanate compound.

6. The tire according to claim 1, wherein: The nitrogen-containing compound includes a compound represented by the following formula (A): In the formula, ring Q 1 represents a group selected from halogen atoms, hydroxyl groups, amino groups, nitro groups, C 1-6 Alkyl, C 1-6 Alkoxy and C 1-6 A benzene ring substituted or unsubstituted with 1 to 3 groups in the group consisting of alkyl-carbonyl; Ring Q 2 represents a group selected from halogen atoms, hydroxyl groups, amino groups, nitro groups, C 1-6 Alkyl, C 1-6 Alkoxy and C 1-6 An imidazole ring which may be substituted by 1 or 2 groups consisting of an alkyl-carbonyl group.

7. The tire according to claim 6, wherein: The content of the compound represented by the formula (A) is 10 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of carbon black.

8. The tire according to claim 1, wherein: The average primary particle size of the carbon black is 30 nm or more and 60 nm or less.

9. The tire according to claim 1, wherein: The average primary particle size of the regenerated carbon black is greater than or equal to 30 nm and less than or equal to 65 nm.

10. The tire according to claim 1, wherein: The regenerated carbon black is obtained by preliminarily surface-treating the regenerated carbon black with the nitrogen-containing compound.

11. The tire according to claim 1, wherein: The ratio A / C of the carbon black content A to the maximum thickness C of the tire component relative to 100 parts by mass of the rubber component is greater than 21.0, wherein A is parts by mass and C is mm.

12. The tire according to claim 1, wherein: The ratio B / C of the nitrogen content B to the maximum thickness C of the tire component relative to 100 parts by mass of the rubber component is less than 0.15, wherein B is parts by mass and C is mm.

13. The tire according to any one of claims 1 to 12, wherein: The groove depth D of the circumferential groove formed in the tread is 5.5 mm or more and 8.5 mm or less.

14. The tire according to claim 13, wherein: The ratio A / D of the carbon black content A to the groove depth D of the circumferential groove formed in the tread relative to 100 parts by mass of the rubber component is 3.0 or more and 9.0 or less; wherein A is parts by mass and D is mm.

15. The tire according to claim 13, wherein: The ratio B / D of the nitrogen content B to the groove depth D of the circumferential groove formed in the tread relative to 100 parts by mass of the rubber component is 0.04 or more and 0.08 or less; wherein B is parts by mass and D is mm.

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