Rubber composition and tire

Abstract

The invention provides a rubber composition and a tire with improved low fuel consumption. The present invention relates to a rubber composition containing a rubber component, a silica containing biomass-derived silica, and a silane coupling agent, the content (C) of the silica being 50 parts by mass or more with respect to 100 parts by mass of the rubber component, the average particle diameter (A) of the silica being 15 nm or less, and the average particle diameter (B) of the silica being 15 nm or less. The content C of the silicon dioxide, the average particle size A of the silicon dioxide and the average carbon atom number E of the silane coupling agent satisfy the following formula (1): (1) E * A / Cgt; and 2.5.

Description

Technical Field

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

[0002] Conventionally, tires have been required to have various performances, and from the viewpoints such as recent environmental considerations, it has been desired to improve low fuel consumption and the like. Summary of the Invention [Problems to be Solved by the Invention]

[0003] An object of the present invention is to solve the above problems and provide a rubber composition and a tire with improved low fuel consumption. [Means for Solving the Problems]

[0004] The present invention relates to a rubber composition comprising a rubber component, silica containing silica derived from biomass, and a silane coupling agent, wherein, based on 100 parts by mass of the rubber component, the content C of the silica is 50 parts by mass or more, the average particle size A of the silica is 15 nm or less, the content C of the silica, the average particle size A of the silica, and the average number of carbon atoms E of the silane coupling agent satisfy the following formula (1). (1) E×A / C>2.5 [Effects of the Invention]

[0005] The present invention is a rubber composition comprising a rubber component, silica containing silica derived from biomass, and a silane coupling agent, wherein, based on 100 parts by mass of the rubber component, the content C of the silica is 50 parts by mass or more, the average particle size A of the silica is 15 nm or less, and the above formula (1) is satisfied, and thus low fuel consumption can be improved. Brief Description of the Drawings

[0006] Figure 1 is a cross-sectional view showing a part of a pneumatic tire. Figure 2 is a magnified cross-sectional view showing the vicinity of the tread of the tire of Figure 1 . [Reference Signs] ​​2: Tire; 4: Tread; 6: Tread sidewall; 8: Bead wing; 10: Lap portion; 12: Bead; 14: Carcass; 16: Belt layer; 18: Band; 20: Inner liner; 22: Bead filler; 24: Tread surface; 26: Groove; 28: Base layer; 30: Running surface layer; 32: Bead core; 34: Apex; 36: Carcass ply; 36a: Main part; 36b: Return part; 38: Inner layer; 40: Outer layer; 42: Main groove; 44: Rib; CL: Equatorial plane of the tire; Tc: Thickness of the tread running surface; D: Main groove depth of the circumferential main groove formed in the tread. Detailed implementation mode

[0007] The rubber composition contains a rubber component, silica containing silica derived from biomass, and a silane coupling agent. Relative to 100 parts by mass of the rubber component, the content C of the silica is 50 parts by mass or more, the average particle size A of the silica is 15 nm or less, and the content C of the silica, the average particle size A of the silica, and the average number of carbon atoms E of the silane coupling agent satisfy the above formula (1).

[0008] The reason for the rubber composition to obtain the above effects is not necessarily clear, but it is speculated as follows. Silica derived from biomass has a tendency to have a higher heat generation due to the strong cohesion between silica with many silanol groups. In addition, when using silica with a small average particle size or compounding a large amount of silica, there is also a tendency to have a higher heat generation. In the above rubber composition, by adjusting the content C of the silica, the average particle size A of the silica, and the number of carbon atoms E of the silane coupling agent to satisfy the formula (1) "E×A / C>2.5", even if a large amount of small-particle silica containing silica derived from biomass is used, since the surface of the silica is hydrophobized, the heat generation can be reduced. Therefore, the low fuel consumption performance can be improved by the above rubber composition.

[0009] In this way, by setting the composition to satisfy the relationship of "E×A / C>2.5", the problem (purpose) of improving the low fuel consumption performance is solved. That is, the parameter of "E×A / C>2.5" is not specified by the problem (purpose). The problem of this application is to improve the low fuel consumption performance, and it is configured to satisfy this parameter as a solution means for this.

[0010] The rubber composition contains a rubber component. Here, the rubber component is a component that contributes to crosslinking. Usually, a polymer with a weight average molecular weight (Mw) of 10,000 or more and a polymer component that is not extracted by acetone belongs to the rubber component. The elastomer component is in a solid state at normal temperature (25°C).

[0011] 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. In addition, it is preferably 2,000,000 or less, more preferably 1,500,000 or less, further preferably 1,000,000 or less. When within the above range, there is a tendency to better obtain the effects.

[0012] It should be noted that in this specification, the weight-average molecular weight (Mw) can be obtained by standard polystyrene conversion based on the measured values obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation). In addition, in the case of a polymer having a modifying group, the modifying group interacts with the silica gel of the column and the correct Mw cannot be obtained. Therefore, Mw is measured before the modification treatment is carried out.

[0013] The rubber component that can be used in the rubber composition may be an unmodified rubber or a modified rubber. As the modified rubber, rubber having a functional group that interacts with a filler such as silica can be cited. For example, terminal-modified rubber (terminal-modified rubber having the above functional group at the terminal) in which at least one terminal of the rubber is modified with a compound (modifying agent) having the above functional group, main-chain modified rubber having the above functional group in the main chain, main-chain terminal-modified rubber having the above functional group in the main chain and at the terminal (for example, main-chain terminal-modified rubber having the above functional group in the main chain and at least one terminal modified with the above modifying agent), and terminal-modified rubber having a hydroxyl group and an epoxy group introduced by modification (coupling) with a polyfunctional compound having two or more epoxy groups in the molecule can be cited.

[0014] As the above functional group, for example, amino group, amide group, silyl group, alkoxysilyl group, isocyanate group, imino group, imidazole group, ureido group, ether group, carbonyl group, oxycarbonyl group, mercapto group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazogroup, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group, etc. can be cited. It should be noted that these functional groups may have substituents. Among them, an amino group (preferably, an amino group in which the hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably, an alkoxy group having 1 to 6 carbon atoms), and an alkoxysilyl group (preferably, an alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

[0015] As the above-mentioned rubber component, for example, a diene rubber can be cited. As the diene rubber, an isoprene rubber, a butadiene rubber (BR), a styrene-butadiene rubber (SBR), a styrene-isoprene-butadiene rubber (SIBR), an ethylene-propylene-diene rubber (EPDM), a chloroprene rubber (CR), an acrylonitrile-butadiene rubber (NBR), etc. can be cited. In addition, as the rubber component, a butyl rubber, a fluororubber, etc. can also be cited. They can be used alone, or two or more of them can be used in combination. In addition, these rubber components can be subjected to modification treatment, hydrogenation treatment, or an extended rubber (extended rubber) increased in amount by an oil, a resin, a liquid rubber component, etc. can be used. Among them, an isoprene rubber, BR, and SBR are preferable, BR and SBR are more preferable, and BR and SBR used in combination are further preferable.

[0016] As the isoprene rubber, a natural rubber (NR), an isoprene rubber (IR), a modified NR, a modified NR, a modified IR, etc. can be cited. As the NR, for example, a conventional product in the rubber industry such as SIR 20, RSS#3, TSR20, etc. can be used. As the IR, there is no particular limitation, and for example, a conventional product in the rubber industry such as IR2200, etc. can be used. As the modified NR, a deproteinized natural rubber (DPNR), a high-purity natural rubber (UPNR), etc. can be cited; as the modified NR, an epoxidized natural rubber (ENR), a hydrogenated natural rubber (HNR), a grafted natural rubber, etc. can be cited; as the modified IR, an epoxidized isoprene rubber, a hydrogenated isoprene rubber, a grafted isoprene rubber, etc. can be cited. They can be used alone, or two or more of them can be used in combination.

[0017] In the above-mentioned rubber composition, in 100% by mass of the rubber component, the content of the isoprene rubber is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, and may be 0% by mass. When within the above range, there is a tendency that appropriate effects can be obtained.

[0018] There is no particular limitation on BR, and for example, a high-cis BR having a high cis content, a BR containing syndiotactic polybutadiene crystals, a BR synthesized using a rare earth catalyst (rare earth BR), etc. can be used. They can be used alone, or two or more of them can be used in combination. Among them, BR preferably contains a high-cis BR having 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 spectrometry.

[0019] Regarding the cis amount of BR, when there is one type of BR, it means the cis amount of that BR, and when there are multiple types of BR, it means the average cis amount. The average cis content of BR can be calculated by {∑(the content of each BR × the cis content of each BR)} / the total content of all BRs. For example, in 100% by mass of the rubber component, when the BR with a cis content of 90% is 20% by mass and the BR with a cis content of 40% is 10% by mass, the average cis content of BR is 73.3% by mass (=(20×90 + 10×40) / (20 + 10)).

[0020] In addition, either unmodified BR or modified BR can be used as BR. As the modified BR, modified BR having the same functional group as the modified rubber can be cited. In addition, hydrogenated butadiene polymer (hydrogenated BR) can also be used as BR.

[0021] In the above rubber composition, in 100% by mass of the rubber component, the content of BR is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more. In addition, it is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less. When within the above range, there is a tendency to obtain appropriate effects.

[0022] There is no particular limitation on SBR. For example, emulsion polymerization styrene-butadiene rubber (E-SBR), solution polymerization styrene-butadiene rubber (S-SBR), etc. can be used. They can be used alone or two or more of them can be used in combination.

[0023] The styrene content of SBR is preferably 5% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass or more. The styrene content is preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less. When within the above range, there is a tendency to better obtain the effects. It should be noted that in this specification, the styrene content can be determined by 1 1H-NMR measurement.

[0024] Regarding the styrene amount of SBR, when there is one kind of SBR, it refers to the styrene amount of that SBR, and when there are multiple kinds of SBR, it refers to the average styrene amount. The average styrene content of SBR can be calculated by {∑(the content of each SBR × the styrene amount of each SBR)} / the total content of all SBRs. For example, in 100% by mass of the rubber component, when the SBR with a styrene amount of 40% is 85% by mass and the SBR with a styrene amount of 25% is 5% by mass, the average styrene amount of SBR is 39.2% by mass (=(85×40 + 5×25) / (85 + 5)).

[0025] The vinyl bond amount of SBR is preferably 3% by mass or more, more preferably 5% by mass or more, and still more preferably 7% by mass or more. The vinyl bond amount is preferably 25% by mass or less, more preferably 15% by mass or less, and still more preferably 13% by mass or less. When within the above ranges, there is a tendency to better obtain the effects. It should be noted that in this specification, the vinyl bond amount (1,2-bonded butadiene unit amount) can be measured by infrared absorption spectrometry.

[0026] The vinyl amount (1,2-bonded butadiene unit amount) of SBR is the proportion of vinyl bonding (unit: % by mass) when the total mass of the butadiene part in SBR is 100. Vinyl amount [% by mass] + cis amount [% by mass] + trans amount [% by mass] = 100 [% by mass]. When there is one type of SBR, it refers to the vinyl amount of this SBR. When there are multiple types of SBR, it refers to the average vinyl amount. The average vinyl amount of SBR can be calculated by ∑{content of each SBR × (100 [% by mass] - styrene amount of each SBR [% by mass]) × vinyl amount of each SBR [% by mass]} / ∑{content of each SBR × (100 [% by mass] - styrene amount of each SBR [% by mass])}. For example, in 100 parts by mass of the rubber component, when 75 parts by mass of SBR has a styrene amount of 40% by mass and a vinyl amount of 30% by mass, 15 parts by mass of SBR has a styrene amount of 25% by mass and a vinyl amount of 20% by mass, and the remaining 10 parts by mass is a rubber component other than SBR, the average vinyl amount of SBR is 28% by mass (= {75 × (100 [% by mass] - 40 [% by mass]) × 30 [% by mass] + 15 × (100 [% by mass] - 25 [% by mass]) × 20 [% by mass]} / {75 × (100 [% by mass] - 40 [% by mass]) + 15 × (100 [% by mass] - 25 [% by mass])}).

[0027] Either unmodified SBR or modified SBR can be used as SBR. As the modified SBR, a modified SBR having the same functional group as the modified rubber can be cited. In addition, as SBR, a hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used.

[0028] In the above rubber composition, in 100% by mass of the rubber component, the content of SBR is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, and preferably 95% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less. When within the above ranges, there is a tendency to better obtain the effects.

[0029] The raw materials (monomers) of synthetic rubbers such as SBR and BR can be derived from petroleum, or recycled from rubber products such as tires or non-rubber products such as polystyrene. As the monomers obtained by recycling (recycled monomers), there is no particular limitation, and examples include recycled butadiene, recycled aromatic ethylene, etc. As the butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the aromatic ethylene, there is no particular limitation, and styrene, etc. can be mentioned. Among them, it is preferable to use recycled butadiene (recycled butadiene) and / or recycled styrene (recycled styrene) as the raw materials.

[0030] As the method for manufacturing recycled monomers, there is no particular limitation. For example, it can be mentioned that it is synthesized from recycled naphtha obtained by decomposing rubber products such as tires. In addition, as the method for manufacturing recycled naphtha, there is no particular limitation. For example, rubber products such as tires can be decomposed under high temperature and high pressure, or can be decomposed under microwaves, or can be extracted after mechanical pulverization.

[0031] In addition, the raw materials (monomers) of synthetic rubbers such as SBR and BR can be derived from biomass. As the monomers derived from biomass (biomass monomers), there is no particular limitation, and examples include biomass-derived butadiene, biomass-derived aromatic ethylene, etc. As the butadiene, 1,2-butadiene and 1,3-butadiene can be mentioned. As the aromatic ethylene, there is no particular limitation, and styrene, etc. can be mentioned. In addition, the method for manufacturing biomass monomers is not particularly limited. For example, it can be mentioned that it is through the biological and / or chemical and / or physical conversion methods of animals and plants. As the biological conversion, typically it is microbial fermentation. As the chemical and / or physical conversion, it can be mentioned that it is through chemical and / or physical conversion by catalysis, high heat, high pressure, electromagnetic waves, critical liquids, and their combinations. As the biomass sources of these monomers, sugar or wood, plant residues after obtaining useful components, ethanol from plants, biomass naphtha, etc. can be mentioned.

[0032] As the polymers synthesized from biomass monomer components (biomass polymers), there is no particular limitation, and examples include: polybutadiene rubber synthesized from biomass-derived butadiene, aromatic ethylene / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic ethylene, etc. As the aromatic ethylene / butadiene copolymer, for example, styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene can be mentioned.

[0033] Whether the raw materials of the polymer are derived from biomass can be judged by pMC (percent Modern Carbon) measured according to ASTM D6866-10.

[0034] pMC refers to the 14 ratio of the 14 C concentration of the sample to that of the standard modern carbon (modern standard reference), and this value is used as an index to indicate the biomass ratio of the compound (rubber). The significance of this value is described as follows.

[0035] Among 1 mole of carbon atoms (6.02×10 23 ), there are approximately one trillionth of the normal carbon atoms, that is, about 6.02×10 11 of 14 C. 14 14 C is called a radioactive isotope, with a half-life of 5730 years and a regular decrease. It takes 226,000 years for all of these to decay. Therefore, in fossil fuels such as coal, oil, and natural gas (which are considered to be produced after more than 226,000 years after carbon dioxide in the atmosphere is taken up and fixed by plants), all of the 14 14 C elements contained in them at the beginning of fixation have decayed. Therefore, in the current 21st century, fossil fuels such as coal, oil, and natural gas do not contain any 14 14 C elements at all. Therefore, chemical substances produced from these fossil fuels also do not contain any 14 14 C elements.

[0036] On the other hand, cosmic rays undergo nuclear reactions in the atmosphere and continuously generate 14 14 C, which balances the decrease in 14 14 C due to radioactive decay. In the atmospheric environment of the earth, the amount of 14 14 C is a certain amount. Therefore, as described above, the 14 14 C concentration of substances from biomass resources involved in the current material cycle is about 1×10 -12 mol% relative to all C atoms as described above. Therefore, the ratio (biomass ratio) of the compound from natural resources (compound from biomass resources) in a certain compound (rubber) can be calculated using the difference between these values.

[0037] This 14 14 C is usually measured as follows. Using accelerator mass spectrometry based on a tandem [type] accelerator, the 13 14 C concentration ( 13 14 C / 12 14 C), 14 14 C concentration ( 14 14 C / 12 14 C) are measured. During the measurement, as the 14Modern Standard Reference for the concentration of C, using the 14 C concentration in the natural carbon cycle in 1950. As a specific reference material, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) is used. The specific radioactivity of carbon in this oxalic acid (the radioactivity intensity of 14 C per 1 g of carbon) is distinguished for each carbon isotope. For 13 C, it is corrected to a fixed value, and the value after decay correction from 1950 AD to the measurement date is used as the standard 14 C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0038] Therefore, if the rubber is made from materials derived from 100% biomass (natural system), although there are regional differences, etc., it shows a value of about 110 pMC (currently, in most cases, it does not reach 100 under normal conditions). On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring the 14 C concentration, it shows about 0 pMC (for example, 0.3 pMC). This value corresponds to a biomass ratio of 0%.

[0039] In summary, using materials such as rubber with a high pMC value, that is, rubber with a high biomass ratio, in the rubber composition is preferred in terms of environmental protection.

[0040] The above rubber composition contains silica, and the silica contains silica derived from biomass.

[0041] As the silica derived from biomass, for example, silica from plants can be cited. As the silica from plants, silica from plants containing silica components can be cited. As plants containing silica components, rice, corn, sugarcane, Equisetum, wheat, barley, rye, Coix lacryma-jobi, millet, panicum miliaceum, Miscanthus, Erianthus, etc. can be cited. In addition, the saccharification treatment residue of plants containing silica components can also be used. Among them, rice husks or rice straw with a high silica content are preferred, and rice husks (rice husk silica) are more preferred. In addition, plants containing silica components can be burned to form ash, or carbonization treatment can be carried out. They can be used alone or two or more of them can be used in combination.

[0042] As the silica that can be used other than silica derived from biomass (hereinafter, also referred to as "other silica"), fumed silica (anhydrous silica), precipitated silica (hydrous silica), etc. can be cited. Among them, precipitated silica is preferred in view of the large number of silanol groups. As commercially available products, products of Degussa, Rhodia, Tosoh Silica Corporation, Solvay Japan, Tokuyama Corporation, etc. can be used. They can be used alone or two or more of them can be used in combination.

[0043] The average particle size A of the silica contained in the above rubber composition is 15 nm or less. The average particle size A of the silica is preferably 14 nm or less, more preferably 13 nm or less. In addition, it is preferably 6 nm or more, more preferably 9 nm or more, and further preferably 10 nm or more. When within the above range, there is a tendency to obtain better effects. It should be noted that the average particle size A of the silica is the average particle size of all types of silica (silica derived from biomass and other silica) contained in the rubber composition. The average particle size of the silica derived from biomass is also preferably in the same range.

[0044] It should be noted that in this specification, the average particle size A of the silica is measured by observing with a transmission electron microscope (TEM). Specifically, a photograph of the silica particles is taken with a transmission electron microscope. When the shape of the particles is spherical, the diameter of the sphere is taken as the particle size. When the shape of the particles is needle-like or rod-like, the minor axis is taken as the particle size. When the shape of the particles is amorphous, the average particle size measured from the center is taken as the particle size, and the average value of the particle sizes of 100 fine particles is taken as the average particle size.

[0045] The nitrogen adsorption specific surface area (N 2 SA) of the silica is preferably 100 m 2 / g or more, more preferably 130 m 2 / g or more, and further preferably 150 m 2 / g or more. The upper limit is preferably 250 m 2 / g or less, more preferably 220 m 2 / g or less, and further preferably 200 m 2 / g or less. When within the above range, there is a tendency to obtain better effects. The average particle size of the silica derived from biomass is also preferably in the same range. It should be noted that in this specification, the N of silica 2 SA is the value measured by the BET method according to ASTM D3037-93.

[0046] The CTAB specific surface area of silica (cetyltrimethylammonium bromide adsorption specific surface area, CTAB) is preferably 100 m 2 / g or more, more preferably 130 m 2 / g or more, and further preferably 150 m 2 / g or more. The upper limit is preferably 250 m 2 / g or less, more preferably 220 m 2 / g or less, and further preferably 200 m 2 / g or less. When within the above range, there is a tendency to obtain better effects. The average particle size of silica derived from biomass is also preferably in the same range. It should be noted that in this specification, the CTAB specific surface area of silica is the value measured according to JIS K6217-3.

[0047] In the above rubber composition, relative to 100 parts by mass of the rubber component, the content C of silica (the total amount of silica derived from biomass and other silica) is 50 parts by mass or more, preferably 60 parts by mass or more, more preferably 70 parts by mass or more, and further preferably 80 parts by mass or more. The upper limit of the content C is preferably 150 parts by mass or less, more preferably 120 parts by mass or less, and further preferably 100 parts by mass or less. When within the above range, there is a tendency to obtain better effects.

[0048] In the above rubber composition, relative to 100 parts by mass of the rubber component, the content of silica derived from biomass is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, further preferably 70 parts by mass or more, and particularly preferably 80 parts by mass or more. The upper limit of the content is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and further preferably 80 parts by mass or less. When within the above range, there is a tendency to obtain better effects.

[0049] The content rate of silica derived from biomass in 100% by mass of the silica contained in the above rubber composition is preferably 60% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and particularly preferably 100% by mass. When within the above range, there is a tendency to obtain better effects.

[0050] The above rubber composition contains a silane coupling agent. In the above rubber composition, the content C of the above silica, the average particle size A of the above silica, and the average number of carbon atoms E of the above silane coupling agent satisfy the following formula (1). (1) E×A / C > 2.5 The right side of formula (1) is preferably 2.8, more preferably 3.0, and further preferably 3.1. The upper limit of E×A / C is preferably 6.0 or less, more preferably 5.0 or less, and further preferably 4.7 or less. When within the above range, there is a tendency to obtain better effects.

[0051] The average number of carbon atoms E of the silane coupling agent contained in the above rubber composition (the average number of carbon atoms of all the silane coupling agents contained in the rubber composition) is preferably 10.0 or more, more preferably 12.0 or more, and further preferably 13.0 or more. Additionally, it is preferably 50.0 or less, more preferably 30.0 or less, and further preferably 20.0 or less. When within the above range, there is a tendency to obtain better effects.

[0052] The number of carbon atoms of each silane coupling agent (silane coupling agent compound) used in the above rubber composition is preferably 10 or more, more preferably 12 or more, and further preferably 13 or more. Additionally, it is preferably 50 or less, more preferably 30 or less, and further preferably 20 or less. When within the above range, there is a tendency to obtain better effects.

[0053] In this specification, the number of carbon atoms of the silane coupling agent (silane coupling agent compound) refers to the total number of carbon atoms in the longest multi-element chain (skeleton) of the carbon atoms in the compound containing the silane coupling agent. For example, the number of carbon atoms E of the silane coupling agent (bis(3-(triethoxysilyl)propyl)tetrasulfide) represented by the following formula (A) is 10, and the number of carbon atoms E of the silane coupling agent (3-octanoylthiopropyltriethoxysilane) represented by the following formula (B) is 13.

Chemical Formula 1

[0054] In this specification, the average number of carbon atoms E of the silane coupling agent is calculated by {∑(the number of carbon atoms of each silane coupling agent × the content of each silane coupling agent)} / the total content of all silane coupling agents. For example, in the case of 3 parts by mass of a silane coupling agent with 10 carbon atoms and 5 parts by mass of a silane coupling agent with 30 carbon atoms relative to 100 parts by mass of the rubber component, the average number of carbon atoms E of the silane coupling agent is 22.5 (= (10×3 + 30×5) / (3 + 5)).

[0055] As the silane coupling agent, for example, mercapto-based silane coupling agents can be appropriately used.

[0056] As the mercapto-based silane coupling agent, a silane coupling agent having a mercapto group, a silane coupling agent in which the mercapto group is protected, etc. can be cited. They may be used alone or two or more of them may be used in combination.

[0057] As a preferable mercapto-based silane coupling agent, a silane coupling agent represented by (i) the following formula (2-1), a silane coupling agent containing a bonding unit A represented by the following formula (2-2) and a bonding unit B represented by the following formula (2-3), etc. can be cited. [Chemical formula 2] (In formula (2-1), R 101 is a monovalent group selected from -Cl, -Br, -OR 106 , -O(O=)CR 106 , -ON=CR 106 R 107 , -NR 106 R 107 and -(OSiR 106 R 107 )(OSiR h )(OSiR 106 R 107 R 108 )(R 106 , R 107 and R 108 may be the same or different and each is a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, and the average value of h is 1 to 4.). R 102 represents R 101 , a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, R 103 represents a -[O(R 109 O) j - group (R 109 is an alkylene group having 1 to 18 carbon atoms, and j is an integer of 1 to 4), R 104 represents a divalent hydrocarbon group having 1 to 18 carbon atoms, R 105 represents a monovalent hydrocarbon group having 1 to 18 carbon atoms, and xa, ya and za are numbers satisfying the relationship of xa + ya + 2za = 3, 0 ≤ xa ≤ 3, 0 ≤ ya ≤ 2, 0 ≤ za ≤ 1.). [Chemical formula 3] [Chemical formula 4] (In formulas (2-2) and (2-3), xb is an integer of 0 or more, and yb is an integer of 1 or more. R 201represents hydrogen, a halogen, a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, a branched or unbranched alkynyl group having 2 to 30 carbon atoms, or a group formed by substituting the hydrogen at the terminal of the alkyl group with a hydroxyl group or a carboxyl group. R 202 represents a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, or a branched or unbranched alkynylene group having 2 to 30 carbon atoms. R 201 and R 202 may form a ring structure.)

[0058] As R 102 , R 105 , R 106 , R 107 and R 108 in the above formula (2-1), specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl, cyclopentyl, cyclohexyl, vinyl, propenyl, allyl, hexenyl, octenyl, cyclopentenyl, cyclohexenyl, phenyl, tolyl, xylyl, naphthyl, benzyl, phenethyl, naphthylmethyl, etc. As an example of R 109 in the above formula (2-1), as a linear alkylene group, examples include methylene, ethylene, n-propylene, n-butylene, hexylene, etc., and as a branched alkylene group, examples include isopropylidene, isobutylene, 2-methylpropylene, etc.

[0059] Specific examples of the silane coupling agent represented by the above formula (2-1) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane, etc. Among them, 3-octanoylthiopropyltriethoxysilane (NXT manufactured by Momentive) is particularly preferred. The above silane coupling agent can be used alone or two or more kinds can be used in combination.

[0060] Compared with polysulfide silanes such as bis-(3-triethoxysilylpropyl)tetrasulfide, the silane coupling agent containing the bonding unit A represented by the formula (2-2) and the bonding unit B represented by the formula (2-3) can suppress the increase in viscosity during processing. It is considered that this is because: the sulfide part of the bonding unit A is a C-S-C bond, so it is thermally stable compared with tetrasulfide or disulfide, and thus the increase in Mooney viscosity is small.

[0061] In addition, compared with mercapto silanes such as 3-mercaptopropyltrimethoxysilane, the shortening of the scorch time is suppressed. It is considered that this is because: the bonding unit A has the structure of a mercapto silane, and the -C 7 H 15 part covers the -SH group of the bonding unit B, so it is difficult to react with the polymer and difficult to cause scorch.

[0062] In the silane coupling agent having the above structure, the content of the bonding unit A is preferably 30 mol% or more, more preferably 50 mol% or more, and further preferably 99 mol% or less, more preferably 90 mol% or less. In addition, from the perspective of reactivity with silica, the content of the bonding unit B is preferably 1 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, and further preferably 70 mol% or less, more preferably 65 mol% or less, still more preferably 55 mol% or less. In addition, the total content of the bonding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%. It should be noted that the contents of the bonding units A and B also include the amounts in the case where the bonding units A and B are located at the ends of the silane coupling agent. The form in the case where the bonding units A and B are located at the ends of the silane coupling agent is not particularly limited as long as units corresponding to the formulas (2-2) and (2-3) representing the bonding units A and B are formed.

[0063] As R 201 of the halogen, chlorine, bromine, fluorine, etc. can be cited.

[0064] As R 201 of the branched or unbranched alkyl group having 1 to 30 carbon atoms, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, etc. can be cited. The number of carbon atoms of this alkyl group is preferably 1 to 12.

[0065] As R 201 of the branched or unbranched alkenyl group having 2 to 30 carbon atoms, vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 1-hexenyl, 2-hexenyl, 1-octenyl, etc. can be cited. The number of carbon atoms of this alkenyl group is preferably 2 to 12.

[0066] As R 201 a branched or unbranched alkynyl group having 2 to 30 carbon atoms, examples thereof include: ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, undecynyl, dodecynyl and the like. The number of carbon atoms of the alkynyl group is preferably 2 to 12.

[0067] As R 202 a branched or unbranched alkylene group having 1 to 30 carbon atoms, examples thereof include: ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecylene, octadecylene and the like. The number of carbon atoms of the alkylene group is preferably 1 to 12.

[0068] As R 202 a branched or unbranched alkenylene group having 2 to 30 carbon atoms, examples thereof include: vinylidene, 1-propenylene, 2-propenylene, 1-butenylene, 2-butenylene, 1-pentenylene, 2-pentenylene, 1-hexenylene, 2-hexenylene, 1-octenylene and the like. The number of carbon atoms of the alkenylene group is preferably 2 to 12.

[0069] As R 202 a branched or unbranched alkynylene group having 2 to 30 carbon atoms, examples thereof include: acetylenylene, propynylene, butynylene, pentynylene, hexynylene, heptynylene, octynylene, nonynylene, decynylene, undecynylene, dodecynylene and the like. The number of carbon atoms of the alkynylene group is preferably 2 to 12.

[0070] In the silane coupling agent containing the bonding unit A represented by the formula (2-2) and the bonding unit B represented by the formula (2-3), the total number of repetitions (xb + yb) of the number of repetitions (xb) of the bonding unit A and the number of repetitions (yb) of the bonding unit B is preferably in the range of 3 to 300. When the total number of repetitions is within this range, since the -C 7 H 15 of the bonding unit A covers the mercapto group of the bonding unit B, it is possible to suppress the shortening of the scorch time, and at the same time, good reactivity with silica and rubber components can be ensured.

[0071] As the silane coupling agent containing the bonding unit A represented by the formula (2-2) and the bonding unit B represented by the formula (2-3), for example, NXT-Z30, NXT-Z45, NXT-Z60 and the like manufactured by Momentive can be used. They can be used alone or in combination of two or more.

[0072] As the mercapto-based silane coupling agent, it is also preferable to use (iii) a silane coupling agent represented by the following formula (2-4).

[0073] [Chemical Formula 5] (In the formula, R 6 ~R 8 represents a branched or unbranched alkyl group having 1 to 12 carbon atoms, a branched or unbranched alkoxy group having 1 to 12 carbon atoms, or -O-(R 111 -O) z -R 112 (z R 111 represents a divalent hydrocarbon group having 1 to 30 carbon atoms which is branched or unbranched. z R 111 may be the same or different from each other. R 112 represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. z represents an integer of 1 to 30.). The groups represented by R 6 ~R 8 may be the same or different from each other. R 9 represents a branched or unbranched alkylene group having 1 to 6 carbon atoms.).

[0074] R 6 ~R 8 represents a branched or unbranched alkyl group having 1 to 12 carbon atoms, a branched or unbranched alkoxy group having 1 to 12 carbon atoms, or a group represented by -O-(R 111 -O) z -R 112 Regarding R 6 ~R 8 , preferably, at least one is a group represented by -O-(R 111 -O) z -R 112 , more preferably, two are groups represented by -O-(R 111 -O) z -R 112 , and one is a branched or unbranched alkoxy group having 1 to 12 carbon atoms.

[0075] As the branched or unbranched alkyl group having 1 to 12 (preferably 1 to 5) carbon atoms for R 6 ~R 8 , for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, etc. can be cited.

[0076] As R 6 ~R8 The alkoxy group having 1 to 12 (preferably 1 to 5) branched or unbranched carbon atoms, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, hexyloxy, heptyloxy, 2-ethylhexyloxy, octyloxy, nonyloxy, etc. can be mentioned.

[0077] R 6 ~R 8 of -O-(R 111 -O) z -R 112 In, R 111 represents a divalent hydrocarbon group having 1 to 30 (preferably 1 to 15, more preferably 1 to 3) branched or unbranched carbon atoms. As this hydrocarbon group, for example, an alkylene group having 1 to 30 branched or unbranched carbon atoms, an alkenylene group having 2 to 30 branched or unbranched carbon atoms, an alkynylene group having 2 to 30 branched or unbranched carbon atoms, an arylene group having 6 to 30 carbon atoms, etc. can be mentioned. Among them, an alkylene group having 1 to 30 branched or unbranched carbon atoms is preferred.

[0078] As R 111 The alkylene group having 1 to 30 (preferably 1 to 15, more preferably 1 to 3) branched or unbranched carbon atoms, for example, methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecylene, octadecylene, etc. can be mentioned.

[0079] As R 111 The alkenylene group having 2 to 30 (preferably 2 to 15, more preferably 2 to 3) branched or unbranched carbon atoms, for example, vinylidene, 1-propenylene, 2-propenylene, 1-butenylene, 2-butenylene, 1-pentenylene, 2-pentenylene, 1-hexenylene, 2-hexenylene, 1-octenylene, etc. can be mentioned.

[0080] As R 111 The alkynylene group having 2 to 30 (preferably 2 to 15, more preferably 2 to 3) branched or unbranched carbon atoms, for example, acetylene, propyne, butyne, pentyne, hexyne, heptyne, octyne, nonyne, decyne, undecyne, dodecyne, etc. can be mentioned.

[0081] As R 111An arylene group having 6 to 30 carbon atoms (preferably 6 to 15 carbon atoms), for example, a phenylene group, a tolylene group, a xylylene group, a naphthylene group, etc. can be cited.

[0082] z is an integer of 1 to 30 (preferably 2 to 20, more preferably 3 to 7, and further preferably 5 to 6).

[0083] R 112 represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an aralkyl group having 7 to 30 carbon atoms. Among them, a branched or unbranched alkyl group having 1 to 30 carbon atoms is preferred.

[0084] As R 112 For the branched or unbranched alkyl group having 1 to 30 carbon atoms (preferably 3 to 25 carbon atoms, more preferably 10 to 15 carbon atoms), for example, the following can be cited: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, octadecyl, etc.

[0085] As R 112 For the branched or unbranched alkenyl group having 2 to 30 carbon atoms (preferably 3 to 25 carbon atoms, more preferably 10 to 15 carbon atoms), for example, the following can be cited: vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 1-hexenyl, 2-hexenyl, 1-octenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, octadecenyl, etc.

[0086] As R 112 For the aryl group having 6 to 30 carbon atoms (preferably 10 to 20 carbon atoms), for example, the following can be cited: phenyl, tolyl, xylyl, naphthyl, biphenyl, etc.

[0087] As R 112 For the aralkyl group having 7 to 30 carbon atoms (preferably 10 to 20 carbon atoms), the following can be cited: benzyl, phenethyl, etc.

[0088] As -O-(R 111 -O) z -R 112 Specific examples of the group represented, for example, include: -O-(C 2 H 4 -O) 5 -C 11 H 23 、-O-(C 2 H 4-O) 5 -C 12 H 25 ,-O-(C 2 H 4 -O) 5 -C 13 H 27 ,-O-(C 2 H 4 -O) 5 -C 14 H 29 ,-O-(C 2 H 4 -O) 5 -C 15 H 31 ,-O-(C 2 H 4 -O) 3 -C 13 H 27 ,-O-(C 2 H 4 -O) 4 -C 13 H 27 ,-O-(C 2 H 4 -O) 6 -C 13 H 27 ,-O-(C 2 H 4 -O) 7 -C 13 H 27 etc. Among them, preferably -O-(C 2 H 4 -O) 5 -C 11 H 23 ,-O-(C 2 H 4 -O) 5 -C 13 H 27 ,-O-(C 2 H 4 -O) 5 -C 15 H 31 ,-O-(C 2 H 4 -O) 6 -C 13 H 27 .

[0089] As the branched or unbranched alkylene group having 1 to 6 carbon atoms (preferably 1 to 5 carbon atoms) of R 9 , for example, it can be exemplified: with R111 Groups having the same alkylene group with 1 to 30 branched or unbranched carbon atoms.

[0090] As the compound represented by the above formula (2-4), for example, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, compounds represented by the following formula (Si363 manufactured by Evonik-Degussa Corporation), etc. Compounds represented by the following formula can be appropriately used. They can be used alone or in combination of two or more.

Chemical Formula 6

[0091] As the silane coupling agent, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, sulfide-based silane coupling agents such as 3-triethoxysilylpropyl methacrylate monosulfide; vinyl-based silane coupling agents such as vinyltriethoxysilane, vinyltrimethoxysilane; amino-based silane coupling agents such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane; glycidoxy-based silane coupling agents such as γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane; nitro-based silane coupling agents such as 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane; chloro-based silane coupling agents such as 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane; polymer-type alkoxy oligomer-type or polyfunctional-type silane coupling agents, etc. They can be used alone or in combination of two or more.

[0092] Among them, from the perspective of low burn-off property, polymer-type alkoxy oligomer-type or polyfunctional-type silane coupling agents are preferred. Specifically, examples include: oligomer-type silane coupling agents containing methoxy / ethoxy and having epoxy groups (such as KR-517 manufactured by Shin-Etsu Silicone Co., Ltd.), oligomer-type silane coupling agents containing methoxy and having epoxy groups (such as KR-516 manufactured by Shin-Etsu Silicone Co., Ltd.), oligomer-type silane coupling agents containing methoxy / ethoxy and having mercapto groups (such as X-41-1805 manufactured by Shin-Etsu Silicone Co., Ltd.), oligomer-type silane coupling agents containing methoxy and having mercapto groups (such as X-41-1810 manufactured by Shin-Etsu Silicone Co., Ltd.), polyfunctional-type silane coupling agents containing ethoxy and having amino groups (such as X-12-972F manufactured by Shin-Etsu Silicone Co., Ltd.), polyfunctional-type silane coupling agents containing ethoxy and having epoxy groups (such as X-12-981S manufactured by Shin-Etsu Silicone Co., Ltd.), polyfunctional-type silane coupling agents containing ethoxy and having epoxy groups (such as X-12-984S manufactured by Shin-Etsu Silicone Co., Ltd.), polyfunctional-type silane coupling agents containing methoxy and having mercapto groups (such as X-12-1154 manufactured by Shin-Etsu Silicone Co., Ltd.), polyfunctional-type silane coupling agents containing methoxy and having isocyanate groups (such as X-12-1252 manufactured by Shin-Etsu Silicone Co., Ltd.), and the like.

[0093] It should be noted that as commercially available products of silane coupling agents, products of companies such as Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., AZmax Co., Ltd., and Toray Dow Corning Co., Ltd. can be used.

[0094] In the above rubber composition, relative to 100 parts by mass of silica, the content Sc (total amount of silane coupling agent) of the silane coupling agent contained is preferably 2 parts by mass or more, more preferably 6 parts by mass or more, and further preferably 10 parts by mass or more. In addition, the above content is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less. When it is below the upper limit, there is a tendency to obtain an effect commensurate with the compounding amount. It should be noted that the content of mercapto-based silane coupling agents is also preferably in the same range.

[0095] In the above rubber composition, relative to 100 parts by mass of silica, the content (total amount of silane coupling agent having 10 or more carbon atoms) of the silane coupling agent having 10 or more carbon atoms is preferably 2 parts by mass or more, more preferably 6 parts by mass or more, and further preferably 10 parts by mass or more. In addition, the above content is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less. When it is below the upper limit, there is a tendency to obtain an effect commensurate with the compounding amount. It should be noted that the content of the silane coupling agent having 13 to 30 carbon atoms is also preferably in the same range.

[0096] The above rubber composition may contain fillers other than silica. As this filler, there is no particular limitation, and materials known in the rubber field can be used. For example, inorganic fillers such as carbon black, calcium carbonate, talc, bauxite, clay, aluminum hydroxide, alumina, mica, and biomass charcoal (BIO CHAR); poorly dispersible fillers, etc. can be cited. Among them, from the perspective of better obtaining effects, carbon-based fillers (carbon-containing fillers) such as carbon black are preferred.

[0097] In the above rubber composition, relative to 100 parts by mass of the rubber component, the content of the filler (total amount of fillers such as silica and carbon black) is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, still more preferably 65 parts by mass or more. In addition, it is preferably 150 parts by mass or less, more preferably 110 parts by mass or less, and still more preferably 85 parts by mass or less. When within the above range, there is a tendency to better obtain effects.

[0098] In the above rubber composition, there is no particular limitation on the carbon black that can be used, and examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan K.K., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin Nippon Carbon Co., Ltd., Columbia Carbon Inc., etc. can be used. They can be used alone or in combination of two or more. In addition, in addition to the conventional carbon black using mineral oil and the like as raw materials, carbon black using biomass materials such as lignin as raw materials can also be used. In addition, recycled carbon black obtained by decomposing rubber products, plastic products, etc. containing carbon black such as tires can be appropriately used in an equivalent replacement with the above carbon black.

[0099] The nitrogen adsorption specific surface area (N 2 SA) of carbon black is preferably 50 m 2 / g or more, more preferably 80 m 2 / g or more, still more preferably 100 m 2 / g or more. In addition, the above N 2 SA is preferably 150 m 2 / g or less, more preferably 130 m2 120 m² / g or less, more preferably 120 m² / g or less. When within the above range, there is a tendency to better obtain the effect. 2 120 m² / g or less. When within the above range, there is a tendency to better obtain the effect. It should be noted that the nitrogen adsorption specific surface area of carbon black is determined according to JIS K6217-2:2001.

[0100] The dibutyl phthalate absorption (DBP) of carbon black is preferably 40 ml / 100 g or more, more preferably 60 ml / 100 g or more, and further preferably 70 ml / 100 g or more. In addition, the above DBP is preferably 200 ml / 100 g or less, more preferably 150 ml / 100 g or less, and further preferably 130 ml / 100 g or less. When within the above range, there is a tendency to better obtain the effect. It should be noted that the DBP of carbon black is determined according to the measurement method of JIS K6217-4:2001.

[0101] In the above rubber composition, the content of carbon black 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 with respect to 100 parts by mass of the rubber component. In addition, it is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 10 parts by mass or less. When within the above range, there is a tendency to better obtain the effect.

[0102] Examples of the hardly dispersible filler include microfibrillated vegetable fibers, short fibrous celluloses, and gel-like compounds. Among them, microfibrillated vegetable fibers are preferred.

[0103] As the microfibrillated vegetable fiber, from the viewpoint of obtaining good reinforcement, cellulose microfibrils are preferred. As the cellulose microfibrils, there is no particular limitation as long as they are cellulose microfibrils derived from natural products. For example, cellulose microfibrils derived from resource-based biomass such as fruits, grains, and root vegetables, wood, bamboo, hemp, jute, kenaf, and pulp or paper, cloth obtained from them, waste biomass such as agricultural crop waste, food waste, or sewage sludge, unused biomass such as rice straw, wheat straw, and thinned wood, and cellulose such as cellulose produced by ascidians and acetic acid bacteria can be mentioned. These microfibrillated vegetable fibers can be used alone or in combination of two or more.

[0104] It should be noted that in this specification, regarding cellulose microfibrils, typically, it refers to cellulose fibers within the range of an average fiber diameter of 10 μm or less, and more typically, it refers to cellulose fibers having a micro-structure with an average fiber diameter of 500 nm or less formed by the aggregation of cellulose molecules. Typical cellulose microfibrils are formed, for example, as aggregates of cellulose fibers having the above-mentioned average fiber diameter.

[0105] When the above 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 still more preferably 5 parts by mass or more, based on 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, still more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less. When within the above range, there is a tendency to obtain better effects.

[0106] The above rubber composition preferably contains a plasticizer. In this specification, a plasticizer is a material that imparts plasticity to the rubber component, and is a concept including both plasticizers that are liquid (in a liquid state) at normal temperature (25°C) and plasticizers that are solid at normal temperature (25°C). Examples of plasticizers include resin components, oils, liquid polymers, ester-based plasticizers, etc. These plasticizers can be derived from petroleum, or can be derived from biomass, or can be derived from naphtha obtained by reusing rubber products or non-rubber products. In addition, low-molecular-weight hydrocarbon components obtained by thermally decomposing and extracting used tires or products containing various components can be used as plasticizers. These plasticizers can be used alone, or two or more of them can be used in combination.

[0107] Specific examples of the above plasticizer include oils, liquid polymers, resins, etc. They can be used alone, or two or more of them can be used in combination.

[0108] As the oil, for example, processing oil, vegetable oil, animal oil, etc. can be cited. As the processing oil, paraffinic processing oil (mineral oil), naphthenic processing oil, aromatic processing oil, etc. can be cited. As specific examples of the processing oil, for example, Mild Extract Solvated (MES), Distillate Aromatic Extract (DAE), Treated Distillate Aromatic Extract (TDAE), Treated Residual Aromatic Extract (TRAE), Residual Aromatic Extract (RAE), etc. can be cited. In addition, for environmental countermeasures, processing oil with a low content of polycyclic aromatic compound (PCA) can also be used. As the above-mentioned low-PCA-content processing oil, MES, TDAE, heavy naphthenic oil, etc. can be cited. In addition, from the perspective of life cycle assessment, oil obtained by refining waste oil used in rubber mixers and engines and waste cooking oil used in restaurants can be used.

[0109] In this specification, as the vegetable oil, 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 nut oil, peanut oil, grape seed oil, wood wax, etc. can be cited. In addition, as the vegetable oil, refined oil (such as salad oil) obtained by refining the above-mentioned oil, transesterified oil obtained by transesterifying the above-mentioned oil, hydrogenated oil obtained by hydrogenating the above-mentioned oil, heat-polymerized oil obtained by heat-polymerizing the above-mentioned oil, oxidation-polymerized oil obtained by oxidizing the above-mentioned oil, waste cooking oil recovered from oil used as edible oil, etc. can also be cited. It should be noted that the vegetable oil can be liquid or solid at normal temperature (25°C). These vegetable oils can be used alone or in combination of two or more.

[0110] The vegetable oil involved in this embodiment preferably contains acylglycerol, and more preferably contains triacylglycerol. It should be noted that in this specification, acylglycerol refers to a compound in which the hydroxyl group of glycerol forms an ester bond with a fatty acid. As the acylglycerol, there is no particular limitation, and it can be 1-monoacylglycerol, or it can be 2-monoacylglycerol, or it can be 1,2-diacylglycerol, or it can be 1,3-diacylglycerol, or it can be triacylglycerol. In addition, the acylglycerol can be a monomer, or it can be a dimer, or it can be a polymer of trimer or higher. It should be noted that acylglycerols of dimer or higher can be obtained by thermal polymerization, oxidative polymerization, etc. In addition, the acylglycerol can be a liquid or a solid at room temperature (25 °C).

[0111] As a method for confirming whether the rubber composition contains the acylglycerol, there is no particular limitation, and it can be confirmed by 1 1H-NMR measurement. For example, the rubber composition compounded with triacylglycerol is immersed in chloroform at room temperature (25 °C) for 24 hours, the rubber composition is removed, and then 1H-NMR is measured at room temperature 1 When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm are observed, and this signal is presumed to be the signal from the hydrogen atom bonded to the carbon atom (this carbon atom is adjacent to the oxygen atom of the ester group). It should be noted that "around" in this paragraph refers to the range of ±0.10 ppm.

[0112] As the fatty acid, there is no particular limitation, and it can be an unsaturated fatty acid or a saturated fatty acid. As the unsaturated fatty acid, examples include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. In addition, as the saturated fatty acid, examples include butyric acid (butanoic acid) and lauric acid.

[0113] Among them, as the fatty acid, it is preferred to contain a fatty acid with fewer double bonds (that is, a saturated fatty acid or a monounsaturated fatty acid), and oleic acid is preferred. As the vegetable oil containing such a fatty acid, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid can be used, or a modified vegetable oil such as transesterified vegetable oil can be used. In addition, in order to produce a vegetable oil containing such a fatty acid, plants can be improved by variety improvement, genetic recombination, genome editing, etc.

[0114] As the vegetable oil, for example, commercially available products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Olisoy Company, H&R Company, Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin OilliO Group Co., Ltd., etc. can be used.

[0115] As the above-mentioned liquid polymer, for example, a diene-based polymer (liquid rubber) or a farnesene-based polymer that is liquid at 25°C can be cited. As the liquid rubber, a liquid styrene-butadiene copolymer (liquid SBR), a liquid butadiene polymer (liquid BR), a liquid isoprene 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. can be cited. The terminals or main chains of these can be modified with polar groups. In addition, hydrides of these can also be used.

[0116] The polystyrene-reduced weight-average molecular weight (Mw) of the above-mentioned liquid diene-based polymer measured by gel permeation chromatography (GPC) is preferably 1.0×10 3 or more, more preferably 3.0×10 3 or more. Additionally, it is preferably 5.0×10 4 or less, more preferably 1.5×10 4 or less. Further, the lower limit or upper limit of Mw of the liquid diene-based polymer can be 4500 or 8500. It should be noted that in this specification, the Mw of the liquid diene-based polymer is the polystyrene-reduced value measured by gel permeation chromatography (GPC).

[0117] As the above-mentioned liquid diene-based polymer, for example, products of Sartomer Company, Kuraray Co., Ltd., etc. can be used.

[0118] As the above-mentioned resin, a commonly used resin can be used as a tire compounding material, and it can be liquid or solid at normal temperature (25°C). For example, an aromatic vinyl polymer, a benzofuran-indene resin, a benzofuran resin, an indene resin, a phenolic resin, a rosin resin, a petroleum resin, a terpene-based resin, an acrylic resin, etc. can be cited. Additionally, the resin can be a hydrogenated resin (hydrogenated resin). They can be used alone or in combination of two or more. Further, the resin itself can be a copolymer from multiple monomer components. Among them, an aromatic vinyl polymer, a petroleum resin, a terpene-based resin, and hydrogenated resins of these are preferred.

[0119] When using a resin that is solid at normal temperature, the softening point of the above-mentioned resin is preferably 50°C or higher, more preferably 55°C or higher, further preferably 60°C or higher, and particularly preferably 85°C or higher. Additionally, 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. When within the above range, there is a tendency to obtain better effects. When the resin is liquid at room temperature, the softening point is preferably 20 °C or lower, more preferably 10 °C or lower, still more preferably 0 °C or lower. The hydrogenated resin preferably has the same softening point as described above. It should be noted that the softening point of the above resin is the temperature at which the ball drops when measured by a ring and ball softening point measuring device in accordance with the softening point specified in JIS K6220-1:2001.

[0120] The above aromatic vinyl polymer is a polymer containing an aromatic vinyl monomer as a constituent unit. For example, resins obtained by polymerizing α-methylstyrene and / or styrene can be cited. Specifically, homopolymers of styrene (styrene resins), homopolymers of α-methylstyrene (α-methylstyrene resins), copolymers of α-methylstyrene and styrene, copolymers of styrene and other monomers, etc. can be cited.

[0121] The above benzofuran-indene resin is a resin containing benzofuran and indene as the main monomer components constituting the resin skeleton (main chain). As monomer components contained in the skeleton other than benzofuran and indene, styrene, α-methylstyrene, methyl indene, vinyl toluene, etc. can be cited.

[0122] The above benzofuran resin is a resin containing benzofuran as the main monomer component constituting the resin skeleton (main chain).

[0123] The above indene resin is a resin containing indene as the main monomer component constituting the resin skeleton (main chain).

[0124] As the above phenolic resin, for example, known phenolic resins such as polymers obtained by reacting phenols with aldehydes such as formaldehyde, acetaldehyde, and furfural using an acid or base catalyst can be used. Among them, phenolic resins (novolac-type phenolic resins, etc.) obtained by reacting them with an acid catalyst are preferred.

[0125] As the above rosin resin, rosin-based resins represented by natural rosin, polymerized rosin, modified rosin, their ester compounds, and their hydrides can be cited.

[0126] As the above petroleum resin, C5-based resins, C9-based resins, C5 / C9-based resins, dicyclopentadiene (DCPD) resins, C9 / DCPD resins, their hydrides, etc. can be cited. Among them, DCPD resins, hydrogenated DCPD resins, C9 / DCPD resins, and C9 / hydrogenated DCPD resins are preferred.

[0127] The above-mentioned terpene resin is a polymer containing terpenes as constituent units. For example, polyterpene resins obtained by polymerizing terpene compounds, aromatic-modified terpene resins obtained by polymerizing terpene compounds and aromatic compounds, etc. can be cited. As the aromatic-modified terpene resin, terphenol resins using terpene compounds and phenolic compounds as raw materials, terpene styrene resins using terpene compounds and styrene-based compounds as raw materials, and terpene phenol styrene resins using terpene compounds, phenolic compounds and styrene-based compounds as raw materials can also be used. It should be noted that as the terpene compound, α-pinene, β-pinene, etc. can be cited, as the phenolic compound, phenol, bisphenol A, etc. can be cited, and as the aromatic compound, styrene-based compounds (styrene, α-methylstyrene, etc.) can be cited. Among them, aromatic-modified terpene resins are preferred.

[0128] The above-mentioned acrylic resin is a polymer containing acrylic monomers as constituent units. For example, styrene-acrylic resins such as styrene-acrylic resins having a carboxyl group and obtained by copolymerizing an aromatic vinyl monomer component and an acrylic monomer component can be cited. Among them, a solvent-free carboxyl group-containing styrene-acrylic resin can be preferably used.

[0129] 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 Corporation, KRATON, Nippon Paint Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., Taoka Chemical Industry Co., Ltd., etc. can be used.

[0130] As the above-mentioned plasticizer, from the perspective of sustainability, it is preferable to use plant-derived plasticizers such as the above-mentioned plant oils and farnesene-based polymers.

[0131] The farnesene-based polymer refers to a polymer obtained by polymerizing farnesene and having a constituent unit based on farnesene. In farnesene, isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and / or β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene) exist, and (E)-β-farnesene having the following structure is preferred.

Chemical Formula 7

[0132] The farnesene-based polymer can be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer). They can be used alone or two or more of them can be used in combination. Among them, a copolymer of farnesene and a vinyl monomer is preferred.

[0133] Examples of the vinyl monomer include: styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinyl ethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyl dimethylamine, (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, vinylxylene, vinylnaphthalene, vinyltoluene, vinylpyridine, diphenylethylene, aromatic vinyl compounds such as diphenylethylene containing a tertiary amino group, or conjugated diene compounds such as butadiene and isoprene. One of them can be used alone or two or more of them can be used in combination. Among them, butadiene is preferred. That is, as the farnesene-vinyl monomer copolymer, a copolymer of farnesene and butadiene (farnesene-butadiene copolymer) is preferred.

[0134] In the farnesene-vinyl monomer copolymer, the copolymerization ratio by mass of farnesene and the vinyl monomer (farnesene / vinyl monomer) is preferably 40 / 60 to 90 / 10.

[0135] The farnesene-based polymer is preferably a farnesene-based polymer having a weight average molecular weight (Mw) of 3,000 or more and 300,000 or less. The Mw of the farnesene-based 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 within the above range, there is a tendency to obtain better effects.

[0136] The farnesene-based polymer can be in either a liquid state or a solid state at normal temperature (25 °C). Among them, a liquid farnesene-based polymer in a liquid state at normal temperature (25 °C) is preferred.

[0137] In the above rubber composition, the content of the plasticizer (total amount of the plasticizer) is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 10 parts by mass or less with respect to 100 parts by mass of the rubber component. The lower limit is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and further preferably 8 parts by mass or more. When within the above range, there is a tendency to obtain better effects. It should be noted that the content of the plasticizer also includes the amounts of oil and resin contained in oil-extended rubber and resin-compatible rubber.

[0138] In the above rubber composition, relative to 100 parts by mass of the rubber component, the content of the solid plasticizer in a solid state at normal temperature (25 °C) is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, and may be 0 parts by mass. When within the above range, there is a tendency to better obtain the effects. It should be noted that the content of the resin in a solid state at normal temperature (25 °C) is also preferably in the same range.

[0139] In the above rubber composition, relative to 100 parts by mass of the rubber component, the content of the liquid plasticizer in a liquid state at normal temperature (25 °C) is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 10 parts by mass or less. The lower limit is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 8 parts by mass or more. When within the above range, there is a tendency to better obtain the effects. It should be noted that the content of the liquid plasticizer also includes the amount of oil contained in oil-extended rubber and the amount of liquid resin of resin-compatible rubber compatibilized with a liquid resin. The content of the oil in a liquid state at normal temperature (25 °C) is also preferably in the same range.

[0140] From the perspective of better obtaining the effects, the above rubber composition preferably contains a compound represented by the following formula (I). The compound represented by the formula (I) can be used alone or two or more thereof can be used in combination. [Chemical formula 8] (In formula (I), R 1 represents a hydrocarbon group. R 2 , R 3 are the same or different and represent a hydrogen atom (-H), a hydrocarbon group, or -(AO) n -H group (n represents an integer of 1 or more, and the respective n of R 2 , R 3 can be the same or different. AO is the same or different and represents an oxyalkylene group having 2 or more carbon atoms.). At least one of R 2 , R 3 is a -(AO) n -H group.)

[0141] R 1 ~R 3The alkyl group can be any of linear, branched, and cyclic, and examples thereof include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, etc. Among them, aliphatic hydrocarbon groups are preferred. The number of carbon atoms of the alkyl group is preferably 1 or more, more preferably 5 or more, further preferably 8 or more, particularly preferably 12 or more. Additionally, it is preferably 30 or less, more preferably 25 or less, further preferably 22 or less, particularly preferably 20 or less. When within the above range, there is a tendency to better obtain the effects.

[0142] Examples of the aliphatic hydrocarbon group include alkyl groups, alkylene groups, alkenyl groups, alkenylene groups, alkynyl groups, alkynylene groups, etc. Among them, alkyl groups having the above-mentioned number of carbon atoms are preferred. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, octadecyl, etc.

[0143] As the alicyclic hydrocarbon group, an alicyclic hydrocarbon group having 3 to 8 carbon atoms is preferred. Specifically, examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, etc.

[0144] As the aromatic hydrocarbon group, an aromatic hydrocarbon group having 6 to 10 carbon atoms is preferred. Specifically, examples thereof include phenyl, benzyl, phenethyl, tolyl group, xylyl group, naphthyl, etc. It should be noted that the substitution position of the methyl group on the benzene ring in the tolyl group and the xylyl group can be any of the ortho, meta, and para positions.

[0145] R 2 、R 3 's -(AO) n -H group (n represents an integer of 1 or more, and each n of R 2 、R 3 can be the same or different. ) The AOs are the same or different and represent an oxyalkylene group having 2 or more carbon atoms. The number of carbon atoms is preferably 3 or more, and the upper limit is not particularly limited, preferably 7 or less, more preferably 6 or less, further preferably 5 or less. When within the above range, there is a tendency to better obtain the effects.

[0146] The alkylene group A in the oxyalkylene group AO can be any of linear and branched. For the reason of more suitably obtaining the effects, AO is preferably a group in which a branched R 4 (R 4 represents an alkyl group. ) is bonded to an oxyalkylene group having 2 to 3 carbon atoms (oxyethylene group (EO), oxypropylene group (PO)), -(AO)n The -H group is more preferably a group represented by the following formula (A) or (B), and further preferably a group represented by the following formula (A). In addition, the branched chain R 4 is preferably bonded to the carbon atom adjacent to the oxygen atom. [Chemical Formula 9] (In formula (A) and (B), R 4 represents a hydrocarbon group. n is the same as n in the -(AO) n -H group.)

[0147] Examples of the hydrocarbon group of R 4 include the same groups as the hydrocarbon groups of R 1 to R 3 . Among them, an aliphatic hydrocarbon group is preferred, and an alkyl group is more preferred. The number of carbon atoms of the hydrocarbon group (preferably an aliphatic hydrocarbon group, more preferably an alkyl group) is preferably 1 or more, more preferably 2 or more, and in addition, preferably 6 or less, more preferably 5 or less, further preferably 4 or less, and particularly preferably 3 or less. When within the above range, there is a tendency to obtain better effects.

[0148] When (AO) n contains two or more kinds of oxyalkylene groups, the arrangement of the oxyalkylene groups can be block or random.

[0149] n represents the number of moles of AO added. n is preferably 1 or more, more preferably 2 or more, and in addition, preferably 20 or less, more preferably 16 or less, further preferably 10 or less, particularly preferably 5 or less, and most preferably 3 or less. When within the above range, there is a tendency to obtain better effects.

[0150] In formula (I), at least one of R 2 and R 3 is a -(AO) n -H group, and more preferably both R 2 and R 3 are -(AO) n -H groups. That is, the compound represented by the above formula (I) is more preferably a compound represented by the following formula (I-1). Thus, there is a tendency to obtain better effects. [Chemical Formula 10] (In formula (I-1), except that n1 and n2 represent integers of 1 or more (the same integers as n), it is the same as formula (I).)

[0151] In formula (I) and (I-1), the total molar addition number of AO (n1 + n2) is preferably 2 or more, more preferably 3 or more, still more preferably 4 or more, and further preferably 40 or less, more preferably 32 or less, still more preferably 20 or less, particularly preferably 10 or less, and most preferably 6 or less. When within the above ranges, there is a tendency to better obtain the effects.

[0152] As specific examples of the compound represented by formula (I), for example, LIPONOLs manufactured by Lion Specialty Chemicals can be cited (in formula (I), R 2 : -(CH 2 CH 2 )x-H, R 3 : -(CH 2 CH 2 )y-H), etc. They can be used alone or two or more of them can be used in combination.

[0153] As specific examples of the compound represented by the above formula (I-1), for example, POE(2) octylamine, POE(4) decylamine, POE(2) dodecylamine, POE(5) dodecylamine, POE(15) dodecylamine, POE(2) tetradecylamine, POE(2) hexadecylamine, POE(2) octadecylamine, POE(20) octadecylamine, POE(2) octadecenylamine, etc. It should be noted that POE(m) represents an average addition of m moles of polyoxyethylene. As commercial products of these, AMIET 102 (POE(2) dodecylamine), AMIET 105 (POE(5) dodecylamine), AMIET 302 (POE(2) octadecylamine), AMIET 320 (POE(20) octadecylamine), etc. manufactured by Kao Corporation can be used.

[0154] As the compound represented by formula (I), the above commercial products, etc. can be used, and in addition, compounds manufactured other than these commercial products can also be used. As a manufacturing method, for example, it can be considered to make an alkylene oxide act on a polyamine compound in the presence of a catalyst or without using a catalyst, but it is not limited to this method.

[0155] In the above rubber composition, relative to 100 parts by mass of the rubber component, the content of the compound represented by formula (I) is preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more. In addition, relative to 100 parts by mass of the rubber component, this content is preferably 10.0 parts by mass or less, more preferably 8.0 parts by mass or less, still more preferably 6.0 parts by mass or less. When the content of the compound is within the above ranges, the effects can be better obtained.

[0156] From the viewpoints of crack resistance, ozone resistance, etc., the above composition preferably contains an antioxidant.

[0157] As the antioxidant, there is no particular limitation, and examples thereof include: naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl) diphenylamine; p-phenylenediamine-based antioxidants such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-dimethylxyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD), etc.; quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bisphenol-based, triphenol-based, polyphenol-based antioxidants such as tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane, etc. Among them, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 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 Industry Co., Ltd., Flexsys Co., etc. can be used.

[0158] In the above rubber composition, relative to 100 parts by mass of the rubber component, the content of the antioxidant is preferably 0.2 parts by mass or more, more preferably 2.0 parts by mass or more, and further preferably 2.5 parts by mass or more. The content is preferably 7.0 parts by mass or less, more preferably 3.5 parts by mass or less.

[0159] The above rubber composition preferably contains stearic acid. In the above rubber composition, relative to 100 parts by mass of the rubber component, the content of stearic acid is preferably 0.5 parts by mass or more, more preferably 2.0 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

[0160] It should be noted that as the stearic acid, conventionally known stearic acid can be used. For example, products of NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Corporation, Chiba Fatty Acids Co., Ltd., etc. can be used.

[0161] The above rubber composition preferably contains zinc oxide. In the above rubber composition, based on 100 parts by mass of the rubber component, 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 5.0 parts by mass or less, more preferably 3.0 parts by mass or less.

[0162] It should be noted that as the zinc oxide, conventionally known zinc oxides can be used. For example, products of Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., HakusuiTech Co., Ltd., Shoindo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0163] In the above rubber composition, wax can be compounded. In the above rubber composition, based on 100 parts by mass of the rubber component, the content of wax is preferably 1.0 parts by mass or more, more preferably 2.0 parts by mass or more, and preferably 10.0 parts by mass or less, more preferably 5.0 parts by mass or less.

[0164] There is no particular limitation on the wax, and examples include petroleum waxes, natural waxes, etc. In addition, synthetic waxes obtained by refining or chemically treating various waxes can also be used. These waxes can be used alone or in combination of two or more.

[0165] Examples of petroleum waxes include paraffin wax, microcrystalline wax, etc. As natural waxes, there is no particular limitation as long as they are waxes derived from resources other than petroleum. For example, plant waxes such as candelilla wax, carnauba wax, wood wax, rice wax, jojoba wax, etc.; animal waxes such as beeswax, lanolin, spermaceti wax, etc.; mineral waxes such as ozokerite, ceresine, petrolatum, etc.; and their refined products, etc. As commercially available products, for example, products of Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Seiko Chemical Co., Ltd., etc. can be used.

[0166] In the above rubber composition, sulfur is preferably compounded in consideration of forming appropriate crosslinked chains on the polymer chain and imparting good properties.

[0167] In the above rubber composition, based on 100 parts by mass of the rubber component, the content of sulfur is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, further preferably 2.0 parts by mass or more. This content is preferably 7.0 parts by mass or less, more preferably 5.0 parts by mass or less, further preferably 4.0 parts by mass or less.

[0168] As sulfur, powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc., which are commonly used in the rubber industry, can be cited. As commercially available products, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexsys, Nippon Kankyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used. They can be used alone or two or more of them can be used in combination.

[0169] The above rubber composition preferably contains a vulcanization accelerator.

[0170] In the above rubber composition, the content of the vulcanization accelerator is not particularly limited and can be freely determined according to the desired vulcanization rate and crosslink density. However, relative to 100 parts by mass of the rubber component, it is preferably 2.0 parts by mass or more, more preferably 4.0 parts by mass or more, and further preferably 4.9 parts by mass or more. The upper limit is preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, and further preferably 6.0 parts by mass or less.

[0171] The type of the vulcanization accelerator is not particularly limited, and commonly used vulcanization accelerators can be used. As the vulcanization accelerator, benzothiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, bis(2-benzothiazolyl) disulfide, and N-cyclohexyl-2-benzothiazolesulfenamide can be cited; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetra(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolesulfenamide, N-tert-butyl-2-benzothiazolylsulfenamide, N-oxydiethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; guanidine-based vulcanization accelerators such as diphenylguanidine, di-o-tolylguanidine, and o-tolylbiguanide. They can be used alone or two or more of them can be used in combination. Among them, sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, and benzothiazole-based vulcanization accelerators are preferred.

[0172] In the above rubber composition, in addition to the above components, compounding agents commonly used in the tire industry, such as mold release agents and other materials, can be appropriately compounded.

[0173] In this specification, various materials containing carbon atoms (for example, rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining the compounded product of the present invention from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process of synthesizing methane from carbon dioxide can be converted.

[0174] The rubber composition can be produced, for example, by kneading the above-mentioned components using a rubber kneading device such as an open roll mill or a Banbury mixer, followed by vulcanization.

[0175] As the mixing conditions, in the basic mixing step of mixing additives other than the crosslinking agent (vulcanizing agent) and the vulcanization accelerator, the mixing temperature is preferably 100°C or more, more preferably 120°C or more, and preferably 180°C or less, and more preferably 170°C or less. In the final mixing step of mixing the vulcanizing agent and the vulcanization accelerator, the mixing temperature is preferably 80°C or more, and preferably 120°C or less, and more preferably 110°C or less. In addition, the composition mixed 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, and more preferably 185°C or less.

[0176] The rubber composition can be used (as a rubber composition for tires) for tire components such as captread, sidewall, base tread, under tread, clinch, bead apex, breaker cushion rubber, carcass cord covering rubber, insulation, chafer, inner liner, sidewall reinforcing layer of run-flat tires, etc. Among them, it is preferably used for captread.

[0177] The tire of the present invention can be manufactured by conventional methods using the above-mentioned rubber composition. That is, in the unvulcanized stage, the composition mixed with various additives as needed is extruded into the shape of various tire components such as the tread surface, and then formed in a tire molding machine in a conventional manner, and bonded together with other tire components to form an unvulcanized tire, and then heated and pressurized in a vulcanizer to manufacture the tire.

[0178] The tire is not particularly limited, and examples thereof include pneumatic tires, solid tires, and non-pneumatic tires (airless tires), etc. Among them, pneumatic tires are preferred.

[0179] The above tires can be suitably used as passenger car tires, large passenger car tires, large SUV tires, truck / 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.

[0180] The above-mentioned tire is preferably a tire having a tread running surface made of the above-mentioned rubber composition.

[0181] In the above-mentioned tire, the thickness Tc (mm) of the tread running surface is preferably 2.0 mm or more, more preferably 3.0 mm or more, further preferably 4.0 mm or more. Additionally, it is preferably 10.0 mm or less, more preferably 9.0 mm or less, and further preferably 8.0 mm or more. When within the above range, there is a tendency to suitably obtain the effects.

[0182] It should be noted that in this specification, the tread running surface refers to the rubber layer that forms the outermost layer in the radial direction of the tire among the rubber layers constituting the tread. In the case of a single-layer tread, the single-layer tread itself; in the case of a two-layer tread of a tread running surface and a tread base, the rubber layer forming the surface; and in the case of a tread having a structure of three or more layers, the rubber layer forming the outermost layer respectively corresponds to the tread running surface.

[0183] The thickness Tc of the tread running surface refers to the thickness of the tread running surface on the tire equatorial plane in the radial cross-section of the tire. In the radial cross-section of the tire, it is the straight-line distance from the tread surface (the surface of the tread running surface) to the inner side surface in the radial direction of the tire of the tread running surface.

[0184] The thickness of the tread running surface on the tire equatorial plane is the respective value measured along the tire equatorial plane from the outermost surface of the tread running surface and the outermost surface of the tread base on the tire equatorial plane. When there are energized components, etc. on the tire equatorial plane, this thickness is the value measured along the tire equatorial plane from the straight line connecting the ends of the interface blocked by the energized component. When there are grooves on the tire equatorial plane, this thickness is the thickness measured at the center in the tire width direction of the land portion closest to the tire equatorial plane, and is the thickness measured in the normal direction of the outer surface in the radial direction of the tire of the tread running surface and the outer surface in the radial direction of the tire of the tread base.

[0185] In the above-mentioned tire, the groove depth D (mm) of the circumferential groove formed in the tread is preferably 3.5 mm or more, more preferably 4.0 mm or more, further preferably 4.5 mm or more. Additionally, it is preferably 8.5 mm or less, more preferably 8.0 mm or less, and more preferably 7.5 mm or less. When within the above range, there is a tendency to better obtain the effects.

[0186] It should be noted that in this specification, the groove depth D of the circumferential groove refers to the distance measured along the normal line of the surface obtained by extending the surface of the ground contact surface forming the outermost surface of the tread, from the surface obtained by extending the surface forming the ground contact surface to the deepest groove bottom, and refers to the maximum distance among the groove depths of the circumferential grooves provided.

[0187] In the above tire, the ratio (Sc / Tc) of the content Sc (parts by mass) of the silane coupling agent to 100 parts by mass of the rubber component in the tread running surface rubber composition to the thickness Tc (mm) of the tread running surface is preferably 0.6 or more, more preferably 0.8 or more, and still more preferably 1.0 or more. The upper limit is preferably 2.5 or less, more preferably 2.2 or less, and still more preferably 2.0 or less. When within the above range, there is a tendency to obtain better effects.

[0188] Although the mechanism by which better effects can be obtained when Sc / Tc is adjusted to a specified value or more is unclear, it is considered that the hydrophobization based on the silane coupling agent becomes better and the heat generation is reduced. Therefore, it is speculated that the low fuel consumption property is improved.

[0189] In the above tire, the ratio (Sc / D) of the content Sc (parts by mass) of the silane coupling agent to 100 parts by mass of the rubber component in the tread running surface rubber composition to the groove depth D (mm) of the circumferential groove formed in the tread is preferably 0.7 or more, more preferably 0.9 or more, and still more preferably 1.0 or more. The upper limit is preferably 2.5 or less, more preferably 2.2 or less, and still more preferably 2.0 or less. When within the above range, there is a tendency to obtain better effects.

[0190] Although the mechanism by which better effects can be obtained when Sc / D is adjusted to a specified value or more is unclear, it is considered that the hydrophobization becomes better due to the silane coupling agent, and thus the heat generation is reduced. Therefore, it is speculated that the low fuel consumption property is improved.

[0191] In this specification, dimensions such as thickness are measured in a state where the bead portion of the tire is adapted to the regular rim width. When measuring, the tire is cut out in the radial direction of the tire, and the bead end portions on both sides of the sample are fixed in a state adapted to the width of the regular rim.

[0192] In this specification, unless otherwise specifically stated, the dimensions of each part of the tire are values measured in the regular state. In this specification, the "regular state" means a non-loaded state in which the tire rim is assembled on a regular rim (not shown) and filled with a regular internal pressure.

[0193] In the case where it is impossible to measure in a state where the tire is assembled on a regular rim, the dimensions and angles of each part in the meridian cross-section of the tire are measured in a cross-section of the tire obtained by cutting the tire along a plane including the rotation axis, such that the distance between the left and right beads is made to coincide with the distance between the beads in the tire assembled on the regular rim.

[0194] "Normal rim" means the rim specified for each tire in a specification system including the specifications on which the tire is based. For example, in JATMA (The Japan Automobile Tire Manufacturers Association), it means the standard rim; in TRA (The Tire and Rim Association, Inc.), it means "Design Rim"; and in ETRTO (The European Tyre and Rim Technical Organisation), it means "Measuring Rim". "Normal internal pressure" means the air pressure specified for each tire in the above-mentioned specifications. In JATMA, it means the maximum air pressure; in TRA, it means the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in ETRTO, it means "INFLATION PRESSURE". "Normal load" means the load specified for each tire in the above-mentioned specifications. In JATMA, it means the maximum load capacity; in TRA, it means the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES"; and in ETRTO, it means "LOAD CAPACITY".

[0195] Hereinafter, an example of the tire of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to such a form.

[0196] Figure 1 In 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 symmetric. The tread 4 includes a running surface layer 30 (tread running surface) and a base layer 28 (tread base).

[0197] It should be noted that although Figure 1 in the figure, an example of the two-layer structure tread 4 composed of the running surface layer 30 and the base layer 28 is shown, it may be a single-layer structure tread or a tread having a structure of three or more layers.

[0198] Figure 1In the tire 2, the tread layer 30 is preferably composed of the above rubber composition. In this case, the tread layer 30 contains a rubber component, silica, and a silane coupling agent. With respect to 100 parts by mass of the rubber component, the content C of the silica is 50 parts by mass or more, the average particle diameter A of the silica is 15 nm or less, and the content C of the silica, the average particle diameter A of the silica, and the average number of carbon atoms E of the silane coupling agent satisfy the formula (1) "E×A / C>2.5". Further, the silica contains silica derived from biomass.

[0199] In the tire 2, each sidewall 6 extends substantially 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 overlapping portion 10. The sidewall 6 can prevent damage to the carcass 14.

[0200] Figure 1 Each bead filler 8 of the tire 2 is located between the tread 4 and the sidewall 6. The bead fillers 8 are respectively joined to the tread 4 and the sidewall 6.

[0201] Each overlapping portion 10 is located substantially radially inward of the sidewall 6 and has at least one portion in contact with the rim.

[0202] The carcass 14 includes a carcass ply 36. In the tire 2, the carcass 14 is composed of one carcass ply 36, but may also be composed of two or more carcass plies.

[0203] In the tire 2, the carcass ply 36 is stretched between the bead cores 32 on both sides and along the tread 4 and the sidewall 6. The carcass ply 36 turns back from the axial inner side toward the outer side around each bead core 32. By this turning back, a main portion 36a and a pair of turned-back portions 36b are formed in the carcass ply 36 layer. That is, the carcass ply 36 includes a main portion 36a and a pair of turned-back portions 36b.

[0204] Each bead core 32 includes a bead apex 34 extending radially outward from the bead core 32. The bead core 32 is annular and preferably includes a wound non-stretchable wire. The bead apex 34 gradually tapers radially outward.

[0205] Although not shown, the carcass ply 36 is preferably formed of a plurality of juxtaposed cords and topping rubber. The absolute value of the angle formed by each cord with respect to the equatorial plane is preferably 75° to 90°. In other words, preferably, the carcass 14 has a radial structure.

[0206] Figure 1 The belt layer 16 is located radially inside the tread 4. The belt layer 16 is laminated on the carcass 14. The belt layer 16 reinforces the carcass 14. Figure 1In the tire 2, the belt layer 16 is composed of an inner layer 38 and an outer layer 40. As can be clearly seen from Figure 1 preferably, in the axial direction, the width of the inner layer 38 is slightly larger than the width of the outer layer 40. In this tire 2, the axial width of the belt layer 16 is preferably 0.6 times or more and preferably 0.9 times or less of the cross-sectional width of the tire 2.

[0207] Preferably, each of the inner layer 38 and the outer layer 40 is formed of a plurality of single-wire steel cord (steel monofilament) arranged in parallel and rubberized rubber (coated rubber). In other words, the belt layer 16 includes a plurality of steel monofilaments arranged in parallel.

[0208] Figure 1 The belt 18 is located radially outside the belt layer 16. In the axial direction, the belt 18 has a width equal to the width of the belt layer 16. The width of the belt 18 may be greater than the width of the belt layer 16.

[0209] Although not shown, preferably, the belt 18 is formed of cord and rubberized rubber. The cord is wound in a spiral shape. The belt 18 has a so-called jointless structure. The cord substantially extends in the circumferential direction. The angle of the cord with respect to the circumferential direction is preferably 5° or less, and more preferably 2° or less. Since the belt layer 16 is constrained by the cord, the lifting of the belt layer 16 is suppressed.

[0210] Figure 1 The belt layer 16 and the belt 18 constitute a reinforcing layer. The reinforcing layer may be composed only of the belt layer 16.

[0211] Figure 2 is Figure 1 an enlarged view near the tread 4. Figure 2 The tire is the tire 2 having a groove 26 on the tire equatorial plane (on the CL). In this case, the thickness (Tc) of the tread running surface is the thickness measured at the center in the tire width direction of the land portion closest to the groove 26 on the tire equatorial plane in the radial cross-section of the tire, and is the thickness measured in the normal direction of the surface of the running surface layer 30 (tread running surface). Specifically, it refers to the straight-line distance in the normal direction between the radially outer surface of the running surface layer 30 and the interface on the outermost surface side of the tire of the base layer 28.

[0212] The inner liner 20 is located inside the carcass 14. The inner liner 20 is joined 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.

[0213] Each bead filler 22 is located near the bead 12. In this embodiment, preferably, the bead filler 22 is formed of a fabric and rubber impregnated in the fabric. The bead filler 22 may be formed integrally with the overlap portion 10.

[0214] In the tire 2, the tread 4 has main grooves 42 as grooves 26. As Figure 1 shown, on the tread 4, a plurality (specifically, three) of main grooves 42 are engraved. These main grooves 42 are arranged at intervals in the axial direction. On the tread 4, by engraving three main grooves 42, four ribs 44 extending in the circumferential direction are formed. That is, between the ribs 44 are the main grooves 42.

[0215] Each main groove 42 extends in the circumferential direction. The main grooves 42 are continuously uninterrupted in the circumferential direction. The main grooves 42 promote the drainage of water existing between the road surface and the tire 2, for example, in rainy weather. Therefore, even when the road surface is wet, the tire 2 can make sufficient contact with the road surface. Figure 2 D represents the groove depth of the circumferential main groove 42 formed on the tread 4.

[0216] In the tire 2, for the content Sc (parts by mass) of the silane coupling agent relative to 100 parts by mass of the rubber component in the tread layer 30, the thickness Tc (mm) of the tread layer 30, and the groove depth D (mm) of the main groove 42, Sc / Tc and Sc / D are preferably within the above ranges. [Examples]

[0217] Hereinafter, examples considered to be preferable in implementation (examples) are shown, but the scope of the present disclosure is not limited to the examples.

[0218] Hereinafter, various chemicals used in the manufacture of the tire are summarized. It should be noted that the chemicals are refined according to conventional methods as needed. SBR: HPR 850 manufactured by JSR Corporation (styrene content: 27.5% by mass, vinyl bond content: 59.0% by mass) BR: BR 730 manufactured by JSR Corporation (cis content: 95% by mass) Carbon black: Shoblack N220 (N manufactured by Cabot Japan Ltd. 2 SA: 114m 2 / g) Silica 1: Ultrasil VN3 manufactured by Evonik Degussa GmbH (average particle size: 19 nm, N 2 SA: 175m 2 / g) Silica 2: K160 manufactured by Wilmar Corporation (average particle size: 15 nm, rice husk silica, N 2 SA: 154 m 2 / g, CTAB: 152 m 2 / g) Silane Coupling Agent 1: Si266 manufactured by Evonik Degussa GmbH (bis(3-triethoxysilylpropyl) disulfide, carbon atom number E: 10) Silane Coupling Agent 2: NXT manufactured by Momentive (3-octanoylthio-1-propyltriethoxysilane, carbon atom number E: 13) Dispersant: LIPONOL HT / 14 manufactured by Lion Specialty Chemical Co., Ltd. (compound represented by the above formula (I-1)) Stearic Acid: Tsubaki manufactured by NOF Corporation Zinc Oxide: Zinc White No. 2 manufactured by Mitsui Mining & Smelting Co., Ltd. Wax: Sunnoc N manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. Antioxidant 1: Nocrac 6C (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. Antioxidant 2: Antage RD (polymer of 2,2,4-trimethyl-1,2-dihydroquinoline) manufactured by Kawaguchi Chemical Industry Co., Ltd. Oil: Diana Process AH-24 manufactured by Idemitsu Kosan Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization Accelerator 1: Nocceler NS (N-tert-butyl-2-benzothiazolylsulfenamide) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd. Vulcanization Accelerator 2: Nocceler D (1,3-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

[0219] <Fabrication of Test Tires> According to the formulation content shown in Table 1, using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd., materials other than sulfur and vulcanization accelerators were kneaded at 150 °C for 5 minutes to obtain a kneaded product. Sulfur and vulcanization accelerators were added to the kneaded product, and using a two-roll mill, it was kneaded at 80 °C for 5 minutes to obtain an unvulcanized rubber composition. The rubber composition for the uncured tread running surface is formed into the shape of the tread running surface, and is bonded to other tire components on a tire building machine to form an uncured tire, which is vulcanized at 170 °C for 10 minutes to manufacture a test tire (size 205 / 70R15, passenger car tire).

[0220] It is assumed that test tires obtained from compositions with varying formulations and specifications according to Table 1, and the results calculated based on the following evaluation methods are shown in each table. It should be noted that the reference comparative examples are as follows. Table 1: Comparative Example 1

[0221] <60 °C tanδ measurement> Samples sized 4 mm in width, 20 mm in length, and 1 mm in thickness are collected from the tread of the test tire (aligning the circumferential direction of the tire with the length direction of the sample). Using an EPLEXOR manufactured by GABO, the loss tangent tanδ is measured under the conditions of a temperature of 60 °C, an initial strain of 10%, a dynamic strain of 1%, a frequency of 10 Hz, and an elongation mode. The reference comparative example is set to 100 for index expression. The larger the index, the lower the heat generation and the better the low fuel consumption performance.

[0222] <Low fuel consumption performance> Using a rolling resistance testing machine, the rolling resistance of each test tire traveling at a speed of 80 km / h is measured, and the reference comparative example is set to 100 for index representation. The larger the index, the smaller the rolling resistance and the better the low fuel consumption performance.

[0223] [Table 1]

[0224] The present invention (1) is a rubber composition comprising a rubber component, silica containing silica derived from biomass, and a silane coupling agent. Based on 100 parts by mass of the rubber component, the content C of the silica is 50 parts by mass or more. The average particle size A of the silica is 15 nm or less. The content C of the silica, the average particle size A of the silica, and the average number of carbon atoms E of the silane coupling agent satisfy the following formula (1): (1) E × A / C > 2.5.

[0225] The present invention (2) is the rubber composition according to the present invention (1), wherein E × A / C > 3.0 is satisfied.

[0226] The present invention (3) is the rubber composition according to the present invention (1) or (2), wherein E × A / C is 5.0 or less.

[0227] The rubber composition of the present invention (4) is an arbitrary combination of any one of the present inventions (1) to (3), wherein, the rubber component contains butadiene rubber and styrene-butadiene rubber, in 100% by mass of the rubber component, the content of the butadiene rubber is 15 to 40% by mass, and the content of the styrene-butadiene rubber is 60 to 85% by mass.

[0228] The rubber composition of the present invention (5) is an arbitrary combination of any one of the present inventions (1) to (4), wherein the silane coupling agent contains a mercapto-based silane coupling agent.

[0229] The rubber composition of the present invention (6) is an arbitrary combination of any one of the present inventions (1) to (5), wherein, relative to 100 parts by mass of the rubber component, the content of the plasticizer is 10 parts by mass or less.

[0230] The present invention (7) is a tire having a tread running surface composed of the rubber composition of an arbitrary combination of any one of the present inventions (1) to (6).

[0231] The present invention (8) is the tire according to the present invention (7), wherein the ratio (Sc / Tc) of the content Sc (parts by mass) of the silane coupling agent to the thickness Tc (mm) of the tread running surface in the tread running surface is 0.8 or more.

[0232] The present invention (9) is the tire according to the present invention (7) or (8), wherein the ratio (Sc / D) of the content Sc (parts by mass) of the silane coupling agent to the groove depth D (mm) of the circumferential groove formed in the tread in the tread running surface is 0.9 or more.

Claims

1. A rubber composition, characterized in that: The rubber composition comprises a rubber component, silica containing biomass-derived silica, and a silane coupling agent. The content C of the silica is 50 parts by mass or more relative to 100 parts by mass of the rubber component, The average particle size A of the silicon dioxide is less than 15 nm, The content C of the silicon dioxide, the average particle size A of the silicon dioxide and the average number of carbon atoms E of the silane coupling agent satisfy the following formula (1): (1)E×A / C>2.

5.

2. The rubber composition according to claim 1, wherein Satisfies E×A / C>3.

0.

3. The rubber composition according to claim 1, wherein E×A / C is 5.0 or less.

4. The rubber composition according to claim 1, wherein The rubber component includes butadiene rubber and styrene butadiene rubber. In 100% by mass of the rubber component, the content of the butadiene rubber is 15% by mass or more and 40% by mass or less, and the content of the styrene butadiene rubber is 60% by mass or more and 85% by mass or less.

5. The rubber composition according to claim 1, wherein The silane coupling agent includes a mercapto-based silane coupling agent.

6. The rubber composition according to claim 1, wherein The content of the plasticizer is 10 parts by mass or less based on 100 parts by mass of the rubber component.

7. A tire, characterized in that: A cap tread comprising the rubber composition according to claim 1.

8. The tire according to claim 7, wherein: The ratio Sc / Tc of the content Sc of the silane coupling agent per 100 parts by mass of the rubber component in the cap tread to the thickness Tc of the cap tread is 0.8 or more, where the unit of Sc is part by mass and the unit of Tc is mm.

9. The tire according to claim 7, wherein: The ratio Sc / D of the content Sc of the silane coupling agent per 100 parts by mass of the rubber component in the cap tread to the groove depth D of the circumferential groove formed in the tread is 0.9 or more, where the unit of Sc is part by mass and the unit of D is mm.

10. The rubber composition according to claim 1, wherein The average carbon number E of the silane coupling agent is greater than or equal to 10.0 and less than or equal to 20.0.

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