Rubber composition for tire and tire

Abstract

The invention provides a rubber composition with excellent rubber strength and a tire. The present invention relates to a rubber composition for tires, comprising: a rubber component containing a modified polymer obtained by reacting a polymer with a polymer modifier having an oxidized nitrile group and a cationic group; a cross-linking agent; carbon black; a plasticizer; and a temperature-responsive material A containing a polymer having a carboxyl group, the content of the crosslinking agent being more than 0 parts by mass and less than 10 parts by mass, the content of the carbon black being more than 0 parts by mass and less than 100 parts by mass, and the content of the plasticizer being more than 5 parts by mass, with respect to 100 parts by mass of the rubber component.

Description

Technical Field

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

[0002] Conventionally, various performances are required for tires, and improvement in rubber strength and the like are desired. Summary of the invention [Problems to be solved by the invention]

[0003] An object of the present invention is to solve the above-mentioned problems and to provide a rubber composition and a tire excellent in rubber strength. [Methods used to solve the problem]

[0004] The present invention relates to a rubber composition for a tire, comprising: A rubber component containing a modified polymer obtained by reacting a polymer having a nitrile oxide group and a cationic group with a polymer modifier; Cross-linking agent; Carbon black; Plasticizers; and A temperature-responsive material A containing a polymer having a carboxyl group, The content of the crosslinking agent is greater than 0 and less than 10 parts by mass, the content of the carbon black is greater than 0 and less than 100 parts by mass, and the content of the plasticizer is greater than 5 parts by mass, relative to 100 parts by mass of the rubber component. [Effects of the Invention]

[0005] According to the present invention, a rubber composition for a tire includes a rubber component containing a modified polymer obtained by reacting a polymer modifier having an oxynitrile group and a cationic group with a polymer, a crosslinking agent, carbon black, a plasticizer, and a temperature-responsive material A containing a polymer having a carboxyl group in a prescribed formulation, so that a rubber composition and a tire having excellent rubber strength can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] [ Figure 1 ] is a schematic diagram illustrating an example of a method for synthesizing a nitrile oxide compound having a nitrile oxide group and a cationic group. [ Figure 2 ]yes Figure 1 The synthesis of compounds P1, P2 and P3 1 An example of a H-NMR (proton NMR) spectrum. [ Figure 3 ] is an example of the result of thermogravimetric analysis during the synthesis of compound P3. [ Figure 4] is an example of a synthesis example in which a nitrile oxide compound having a nitrile oxide group and a cationic group reacts with a polymer having a double bond to synthesize a polymer having a cationic group. [ Figure 5 ]yes Figure 4 The synthetic route of the polymer 1 An example of a H-NMR (proton NMR) spectrum. [ Figure 6 ] is a schematic diagram illustrating an example of a method for synthesizing a nitrile oxide compound having a nitrile oxide group and an anionic group. DETAILED DESCRIPTION

[0007] The present invention is a rubber composition for tires, which comprises, in a prescribed formulation, a rubber component containing a modified polymer obtained by reacting a polymer modifier having an oxynitrile group and a cationic group with a polymer, a crosslinking agent, carbon black, a plasticizer, and a temperature-responsive material A containing a polymer having a carboxyl group.

[0008] Although the reason why the above-mentioned effects are obtained is not clear, it is presumed as follows. The cationic group of the modified polymer forms a hydrogen bond with the carboxyl group of the temperature responsive material A, thereby reducing the hydrophilicity of the temperature responsive material A and improving the dispersibility of the temperature responsive material A in the rubber. Furthermore, the nitrile oxide group of the modified polymer is bonded to the rubber, and the rubber and the temperature responsive material A are bonded or interacted with each other via the nitrile oxide compound having the nitrile oxide group and the cationic group, thereby improving the strength of the rubber. Furthermore, the cationic groups of the modified polymer interact with the carboxyl groups of the temperature responsive material A, making it difficult for the modified polymer to fall off, thereby improving the rubber strength. Therefore, the rubber strength is improved by the above-mentioned rubber composition for a tire.

[0009] The rubber composition contains, as a rubber component, a modified polymer obtained by reacting a nitrile oxide compound (polymer modifier) ​​having a nitrile oxide group and a cationic group with a polymer.

[0010] In the above-mentioned nitrile oxide compound (polymer modifier) ​​having a nitrile oxide group and a cationic group, the nitrile oxide group is a group represented by the following formula: The nitrile oxide compound may be a compound having one nitrile oxide group, or may be a compound having two or more nitrile oxide groups.

[0011]

[0012] In the above-mentioned nitrile oxide compound having a nitrile oxide group and a cationic group, preferably, the cationic group is introduced into the terminal of the nitrile oxide compound. The above-mentioned nitrile oxide compound may be a compound having one cationic group, or may be a compound having two or more cationic groups. In addition, the cationic group in the above-mentioned nitrile oxide compound may be one or more than two.

[0013] As the above-mentioned cationic group, the univalent cationic groups of amino, ammonium, imino and their salts etc. can be listed. As the atom or atomic group constituting the salt, hydroxide ion, halogen ion, carboxylate ion, sulfonate ion, fluoride ion, cyanide ion, silicate ion, borate ion, condensed phosphate ion etc. can be listed. It should be noted that the amino group listed as an example of the cationic group is not limited to -NH2, and also includes substituted amino and cyclic amino. As substituted amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkylarylamino etc. can be listed. Examples of the cyclic amino group include pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, pyrrolyl, pyrazolyl, imidazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrrolidonyl, piperidinonyl, 3-morpholinonyl, morpholinedionyl, and substituted groups thereof, and examples of the substituent include halogen groups and monovalent hydrocarbon groups (alkyl, alkenyl, etc.). Among them, from the perspective of obtaining a better effect, a cyclic amino group is preferred, and a pyridinyl and substituted pyridinyl are more preferred.

[0014] Typical examples of the pyridyl group which may be substituted as required include the following 2-pyridyl group, 3-pyridyl group, and 4-pyridyl group: And, the following 3-pyridyl substituted with -CH3: wait.

[0015] The compound having a nitrile oxide group and a cationic group is not particularly limited, and examples thereof include compounds represented by the following formula. XC≡N + -O - (In the formula, X represents a monovalent hydrocarbon group containing a cationic group.)

[0016] X is not particularly limited as long as it is a monovalent hydrocarbon group containing a cationic group. In addition, the cationic group contained in X can be, for example, the same group as the above-mentioned cationic group. Regarding the cationic group contained in X, it is preferably formed at the end of X, for example, as shown by X being a group represented by -(CH2)5-A (A: cationic group).

[0017] The monovalent hydrocarbon group in X (a monovalent hydrocarbon group containing a cationic group) refers to a monovalent hydrocarbon group constituting the skeleton of X and in which the cationic group is substituted with a hydrogen atom. For example, when X is a group represented by -(CH2)5-C5H4N (pyridyl: cationic group), the monovalent hydrocarbon group in X is -(CH2)5-H.

[0018] As the monovalent hydrocarbon group in X, substituted or unsubstituted monovalent hydrocarbon groups can be listed, which can be any of linear, branched, and cyclic, preferably cyclic. In addition, the monovalent hydrocarbon group in X may contain heteroatoms. As substituents, there are no particular restrictions, and well-known groups such as hydroxyl groups, halogen groups (-Cl, -Br, etc.) can be listed. As heteroatoms, there are no particular restrictions, and oxygen, nitrogen, etc. can be listed. These substituents and heteroatoms may have one or more.

[0019] The number of carbon atoms in the monovalent hydrocarbon group in X is preferably 3 or more, more preferably 6 or more, and is preferably 30 or less, more preferably 20 or less, and further preferably 16 or less.

[0020] Examples of the monovalent hydrocarbon group in X include substituted or unsubstituted linear alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, and aralkyl groups that may contain heteroatoms. In addition, the monovalent hydrocarbon group in X may be a group formed by combining these substituted or unsubstituted linear alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, and aralkyl groups that may contain heteroatoms (a group formed by combining a substituted or unsubstituted linear alkyl group that may contain heteroatoms and a substituted or unsubstituted aryl group that may contain heteroatoms, etc.).

[0021] Among the monovalent hydrocarbon groups in X, examples of substituted or unsubstituted straight-chain alkyl and branched-chain alkyl groups that may contain heteroatoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, and these groups containing heteroatoms. Examples of substituted or unsubstituted cyclic alkyl groups that may contain heteroatoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl, 1-ethylcyclopentyl, 1-ethylcyclohexyl, and these groups containing heteroatoms. Examples of substituted or unsubstituted aryl groups that may contain heteroatoms include phenyl, tolyl, xylyl, biphenyl, naphthyl, anthracenyl, phenanthryl, and these groups containing heteroatoms. Examples of substituted or unsubstituted aralkyl groups that may contain heteroatoms include benzyl, phenethyl, and these groups containing heteroatoms. Examples of the monovalent hydrocarbon group in X include groups formed by combining these groups (a group formed by combining a substituted or unsubstituted pentyl group which may contain a heteroatom and a substituted or unsubstituted naphthyl group which may contain a heteroatom, etc.).

[0022] The monovalent hydrocarbon group in X is preferably a substituted or unsubstituted straight-chain alkyl group which may contain a heteroatom, a substituted or unsubstituted aryl group which may contain a heteroatom, or a group formed by combining a substituted or unsubstituted straight-chain alkyl group which may contain a heteroatom and a substituted or unsubstituted aryl group which may contain a heteroatom.

[0023] The compound having an oxynitrile group and a cationic group is preferably a compound having a cyclic structure, and more preferably a compound having an aromatic ring. Specific examples of aromatic rings include: a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, a triphenylene ring, a tetracene ring, a biphenyl ring, a bisphenol ring, a terphenyl ring (three benzene rings can be connected in any connection mode), etc. Among them, compounds having a benzene ring and a naphthalene ring are preferred, and compounds having a naphthalene ring are more preferred.

[0024] Preferred examples of the nitrile oxide compound having a nitrile oxide group and a cationic group include compounds represented by the following formula (compounds having a naphthalene ring).

[0025] (In the formula, A represents a monovalent cationic group. Y represents a substituted or unsubstituted divalent hydrocarbon group which may contain a heteroatom.)

[0026] Examples of A (monovalent cationic group) include the monovalent cationic groups described above.

[0027] Y (a substituted or unsubstituted divalent hydrocarbon group which may contain a heteroatom) may be any of a linear, branched, or cyclic shape. In addition, as heteroatoms and substituents in Y, for example, the above-mentioned heteroatoms and substituents may be listed. Y may have one of these substituents and heteroatoms, or may have two or more of these substituents and heteroatoms.

[0028] The number of carbon atoms of the divalent hydrocarbon group in Y is preferably 1 or more, and is preferably 20 or less, more preferably 10 or less, and further preferably 6 or less.

[0029] Examples of Y (a substituted or unsubstituted divalent hydrocarbon group which may contain a hetero atom) include a substituted or unsubstituted alkylene group, an alkenylene group, a cycloalkylene group, a cycloalkylalkylene group, an arylene group, an aralkylene group, and an oxyalkylene group which may contain a hetero atom.

[0030] As substituted or unsubstituted alkylene groups which may contain heteroatoms, methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, octylene, nonylene, decylene, 1,2-propylene, and groups containing heteroatoms thereof, etc. can be cited. As substituted or unsubstituted alkenylene groups which may contain heteroatoms, vinylene, 1-propylene, 2-propylene, and groups containing heteroatoms thereof, etc. can be cited. As substituted or unsubstituted cycloalkylene groups which may contain heteroatoms, cyclohexylene, and groups containing heteroatoms thereof, etc. can be cited. As substituted or unsubstituted cycloalkylalkylene groups which may contain heteroatoms, cyclohexylmethylene, and groups containing heteroatoms thereof, etc. can be cited. As substituted or unsubstituted arylene groups which may contain heteroatoms, phenylene, tolylene group, xylylene group, and groups containing heteroatoms thereof, etc. can be cited. Examples of the substituted or unsubstituted aralkylene group which may contain a hetero atom include a benzylidene group and such groups containing a hetero atom. Examples of the substituted or unsubstituted oxyalkylene group which may contain a hetero atom include oxyethylene group, oxypropylene group, oxybutylene group, oxytetramethylene group and such groups containing a hetero atom.

[0031] The compound having a naphthalene ring represented by the above formula is one preferred example. + -O - The substitution position of the group represented by -YA is not particularly limited, and may be any one of positions 1 to 8. Preferably, positions 1 and 2 are replaced by -C≡N + -O - , -YA replaced.

[0032] Next, the synthesis method of the nitrile oxide compound having the nitrile oxide group and the cationic group is described. Hereinafter, an example of the synthesis method of the nitrile oxide compound having the nitrile oxide group and the cationic group is described, but the nitrile oxide compound is not limited to the nitrile oxide compound obtained by such a synthesis method, and includes compounds obtained by any synthesis method that can be synthesized.

[0033] First, a compound having a hydroxyl group and an aldehyde group is used as a starting material, and the compound having a hydroxyl group and an aldehyde group is reacted with a compound capable of introducing a cationic group. If necessary, a group derived from the compound capable of introducing a cationic group in the obtained material is substituted with the cationic group.

[0034] Next, the aldehyde group in the obtained compound is converted into a group represented by -CH=N-OH, and the group represented by -CH=N-OH is further converted into a group represented by -C≡N + -O --, a nitrile oxide compound having a nitrile oxide group and a cationic group can be synthesized.

[0035] It should be noted that the reaction process can be carried out in an organic solvent, in water, or in the absence of a solvent. The organic solvent is not particularly limited, and is preferably a solvent in which the compound to be reacted and the reaction compound are easily soluble. As an organic solvent, it is not particularly limited, and examples thereof include: toluene, mesitylene, chloroform (CHCl3), alcohol, THF (tetrahydrofuran), etc. In addition, a catalyst can be used as needed. As a catalyst, it is not particularly limited, and examples thereof include: DMF (N, N-dimethylformamide), DMSO (dimethyl sulfoxide), triethylamine (TEA), etc. The amount of solvent and the amount of catalyst can be appropriately set according to the compound. The reaction temperature and time can also be appropriately set according to the compound. Regarding the reaction temperature, for example, 10 to 100°C can be cited, preferably 20 to 80°C, and regarding the reaction time, for example, 1 to 200 hours can be cited, preferably 3 to 100 hours.

[0036] The synthesis examples of specific compounds are described. For example, Figure 1 The synthetic route shown can synthesize a nitrile oxide compound having a nitrile oxide group and a cationic group represented by compound P3.

[0037] First, compound S (a compound having a hydroxyl group and an aldehyde group) is used as a starting material, and the compound S is reacted with a compound capable of introducing a cationic group (C5H4N-CH2-Cl (wherein C5H4N represents a 2-pyridyl group)) to obtain compound P1.

[0038] The aldehyde group in the obtained compound P1 is converted into a group represented by -CH=N-OH to synthesize compound P2. The group represented by -CH=N-OH in the obtained compound P2 is converted into a group represented by -C≡N + -O - The group represented by the formula (a) was used to synthesize compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic group).

[0039] Figure 2 yes Figure 1 The synthesis of compounds P1, P2, and P3 1 An example of a H-NMR (proton NMR) spectrum. Figure 3 This is an example of the result of thermogravimetric analysis (TGA) during the synthesis of compound P3 (nitrile oxide compound (CNO-Py) having a nitrile oxide group and a cationic group). Figure 2 The spectra of Figure 3 The results of TGA are shown in Figure 1 Compounds P1, P2, and P3 were synthesized using the synthetic route.

[0040] The modified polymer obtained by reacting the above-mentioned nitrile oxide compound (polymer modifier) ​​having a nitrile oxide group and a cationic group with a polymer is a modified polymer obtained by reacting the above-mentioned nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer (a polymer having an unsaturated bond, etc.). By using this modified polymer, mechanical properties, etc. are improved.

[0041] Although the mechanism by which the above-mentioned effects are obtained is not clear, it is presumed as follows. Since the above-mentioned nitrile oxide compound with nitrile oxide group and cationic group can react with various unsaturated polymers, it is easy to add the nitrile oxide compound to unsaturated polymers such as diene rubber, and the polymer with ionic bonding point (position for forming ionic bond) can be easily synthesized, and in addition, the content of ionic bonding point in the polymer is also easily adjusted. The ionically bonded polymer has ion clusters in the polymer, and mechanical properties are improved. Therefore, rubber strength is improved.

[0042] The method for reacting the nitrile oxide compound having the nitrile oxide group and the cationic group with the polymer may adopt any method that can react. For example, as required, the nitrile oxide compound and the polymer having the unsaturated bond may be dissolved or energized, thereby causing a cycloaddition reaction between the nitrile oxide group and the carbon-carbon double bond in the main chain of the polymer, and a reaction to generate a five-membered ring may be performed.

[0043] Examples of the polymer include polymers having a carbon-carbon double bond. As the polymer having carbon-carbon double bonds, for example, rubber components such as diene rubbers can be cited. As diene rubbers, isoprene rubbers, butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), etc. can be cited. In addition, butyl rubbers, fluororubbers, etc. can also be cited. Among them, from the perspective of rubber strength, SBR, BR, and isoprene rubbers are preferred.

[0044] The above-mentioned diene rubber may be an unmodified diene rubber or a modified diene rubber. The modified diene rubber may be any diene rubber having a functional group that interacts with a filler such as silica, and examples thereof include a terminal-modified diene rubber obtained by modifying at least one terminal of a diene rubber with a compound (modifier) ​​having the functional group (terminal-modified diene rubber having the functional group at the terminal), a main chain-modified diene rubber having the functional group on the main chain, a main chain-terminal-modified diene rubber having the functional group on the main chain and the terminal (for example, a main chain-terminal-modified diene rubber having the functional group on the main chain and at least one terminal modified with the modifier), and a terminal-modified diene rubber into which a hydroxyl group or an epoxy group is introduced by modification (coupling) with a polyfunctional compound having two or more epoxy groups in the molecule.

[0045] As the functional group, for example, amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazole, urea, ether, carbonyl, oxycarbonyl, mercapto, sulfide, disulfide, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imido, hydrazine, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy, hydroxyl, oxy, epoxy, etc. are listed. It should be noted that these functional groups may have a substituent. Among them, amino (preferably, an amino group in which the hydrogen atom of the amino group is replaced by an alkyl group having 1 to 6 carbon atoms), alkoxy (preferably, an alkoxy group having 1 to 6 carbon atoms), and alkoxysilyl (preferably, an alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

[0046] The SBR is not particularly limited, and for example, emulsion polymerized styrene butadiene rubber (E-SBR), solution polymerized styrene butadiene rubber (S-SBR), etc. can be used. These can be used alone or in combination of two or more.

[0047] The styrene content of SBR is preferably 5% by mass or more, more preferably 20% by mass or more, and further preferably 24% by mass or more. The styrene content is preferably 60% by mass or less, more preferably 40% by mass or less, and further preferably 35% by mass or less. Within the above range, there is a tendency to obtain better effects. It should be noted that, in this specification, the styrene content can be 1 The results were determined by H-NMR measurement.

[0048] The styrene amount of SBR refers to the styrene amount of the SBR when there is one type of SBR, and refers to the average styrene amount when there are multiple types of SBR. The average styrene content of SBR can be calculated by {∑(content of each SBR×styrene content of each SBR)} / total content of all SBRs. For example, in 100% by mass of the rubber component, when SBR with a styrene content of 40% by mass is 85% by mass and SBR with a styrene content of 25% by mass is 5% by mass, the average styrene content of SBR is 39.2% by mass (=(85×40+5×25) / (85+5)).

[0049] The vinyl bonding amount of SBR is preferably 3% by mass or more, more preferably 10% by mass or more, and further preferably 17% by mass or more. The vinyl bonding amount is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. Within the above range, there is a tendency to obtain better effects. In addition, in this specification, the vinyl bond amount (1,2-bonded butadiene unit amount) can be measured by infrared absorption spectroscopic analysis.

[0050] The vinyl amount (1,2-bonded butadiene unit amount) of SBR is the ratio of vinyl bonds (unit: mass%) when the total mass of the butadiene part in SBR is 100, vinyl amount [mass%] + cis amount [mass%] + trans amount [mass%] = 100 [mass%]. When there is one type of SBR, it refers to the vinyl amount of the SBR, and when there are multiple types of SBR, it refers to the average vinyl amount. The average vinyl content of SBR can be calculated by ∑{content of each SBR×(100[mass%]-styrene content of each SBR[mass%])×vinyl content of each SBR[mass%]} / ∑{content of each SBR×(100[mass%]-styrene content of each SBR[mass%])}. For example, in 100 parts by mass of the rubber component, 75 parts by mass are SBRs having a styrene content of 40% and a vinyl content of 30%, and 25 parts by mass are SBRs having a styrene content of 25% and a vinyl content of 30%. When SBR having a vinyl content of 20% by mass accounts for 15 parts by mass and the remaining 10 parts by mass are other than SBR, the average vinyl content of SBR is 28% by mass (={75×(100[mass%]-40[mass%])×30[mass%]+15×(100[mass%]-25[mass%])×20[mass%])} / {75×(100[mass%]-40[mass%])+15×(100[mass%]-25[mass%])}.

[0051] SBR can use any one of unmodified SBR and modified SBR. As modified SBR, modified SBR introduced with the same functional group as modified rubber can be enumerated. In addition, as SBR, hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used.

[0052] As SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Corporation, etc. can be used. In addition, SBR synthesized by a known method can also be used.

[0053] BR is not particularly limited, for example, high cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, BR synthesized using a rare earth catalyst (rare earth BR), etc. can be used. They can be used alone, or two or more can be used in combination. Among them, BR preferably includes a high cis BR with a cis content of 90% by mass or more. The cis content is more preferably 95% by mass or more. It should be noted that the cis content can be measured by infrared absorption spectroscopy.

[0054] The cis-amount of BR refers to the cis-amount of the BR when there is one type of BR, and refers to the average cis-amount when there are multiple types of BR. The average cis content of BR can be calculated by {∑(content of each BR×cis content of each BR)} / total content of all BRs. For example, in the rubber component of 100 mass%, when BR with a cis content of 90 mass% is 20 mass% and BR with a cis content of 40 mass% is 10 mass%, the average cis content of BR is 73.3 mass% (=(20×90+10×40) / (20+10)).

[0055] In addition, BR may be either unmodified BR or modified BR. As the modified BR, there may be mentioned a modified BR into which the same functional group as the modified rubber is introduced. In addition, a hydrogenated butadiene polymer (hydrogenated BR) may be used as BR.

[0056] As BR, for example, products of Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Corporation, etc. can be used.

[0057] As isoprene-based rubber, natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, etc. can be listed. As NR, for example, NR commonly used in the rubber industry such as SIR20, RSS#3, TSR20, etc. can be used. As IR, there is no particular limitation, for example, IR commonly used in the rubber industry such as IR2200 can be used. As modified NR, deproteinized natural rubber (DPNR), high purity natural rubber (UPNR), etc. can be listed; as modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. can be listed; as modified IR, epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. can be listed. They can be used alone, or two or more types can be used in combination.

[0058] The reaction process of the above-mentioned nitrile oxide compound and the polymer such as the above-mentioned diene rubber is not particularly limited, and can be carried out in an organic solvent, in water, or can be carried out without a solvent. As the organic solvent, it is not particularly limited, and it is preferred that the above-mentioned nitrile oxide compound and the polymer are both easily soluble in an organic solvent. As a specific example of the organic solvent, for example, the above-mentioned organic solvent can be cited. The reaction temperature and time can be appropriately set according to the above-mentioned nitrile oxide compound and the above-mentioned polymer.

[0059] In particular, even in the absence of a solvent, the polymer and the nitrile oxide compound can be kneaded to react with each other. During kneading, a modified polymer obtained by the reaction of the nitrile oxide compound having a nitrile oxide group and a cationic group with the polymer can be obtained. In addition, during the kneading of the polymer and the nitrile oxide compound, a modified polymer is generated by the reaction of the nitrile oxide compound having a nitrile oxide group and a cationic group with the polymer. Further, during kneading, the modified polymer interacts with the temperature-responsive material A described later, thereby obtaining the strength of the gel. During the kneading process, the reaction temperature (kneading temperature) and the reaction time (kneading time) can be appropriately set as long as the temperature and time of the reaction are carried out. The reaction temperature (kneading temperature) is preferably 10 to 100°C, more preferably 50 to 80°C, and the reaction time (kneading time) is preferably 1 minute to 200 hours, more preferably 3 minutes to 100 hours, and more preferably 5 minutes to 1 hour.

[0060] The synthesis examples of specific compounds are described. For example, Figure 4 The synthetic route shown can synthesize a reaction product (modified polymer) of the above-mentioned nitrile oxide compound having a nitrile oxide group and a cationic group and a polymer having a double bond.

[0061] For example, by kneading the nitrile oxide compound having a nitrile oxide group and a cationic group (the above-mentioned compound P3) with BR and SBR (diene rubber) at 70° C. for 15 minutes, the target reaction product (modified polymer having a cationic group) can be obtained. In addition, a high reaction rate of the above-mentioned compound P3 can be obtained.

[0062] Figure 5 yes Figure 4 The synthetic route of the polymer 1 An example of a H-NMR (proton NMR) spectrum. (A) is BR 1 An example of H-NMR spectrum, (B) is SBR 1 An example of H-NMR spectrum, (C) is BR having a pyridyl group (cationic group) 1 An example of H-NMR spectrum, (D) is SBR having a pyridyl group (cationic group)1 An example of H-NMR spectrum. Figure 5 (C) and (D) represent the reaction of a nitrile oxide compound having a nitrile oxide group and a cationic group (the above-mentioned compound P3) with BR and SBR to synthesize a polymer having a cationic group.

[0063] The rubber composition is a rubber composition containing the modified polymer (hereinafter also referred to as "modified polymer (A)") obtained by reacting the nitrile oxide compound having a nitrile oxide group and a cationic group with the polymer as a rubber component, but may also be a composition in which a modified polymer synthesized in advance by the above-mentioned production method is mixed with other components, or may be a composition containing the following modified polymer: when the polymer such as the above-mentioned diene rubber, the above-mentioned nitrile oxide compound having a nitrile oxide group and a cationic group, and other components as required are kneaded under the above-mentioned kneading conditions, etc., and the polymer is kneaded to produce a modified polymer, and the polymer reacts with the nitrile oxide compound during kneading.

[0064] The rubber composition may contain, as the rubber component, a modified polymer (B) obtained by reacting a nitrile oxide compound having a nitrile oxide group and anionic groups with a polymer in addition to the modified polymer (A) in order to obtain better effects.

[0065] As the above-mentioned anionic group, halogen groups, acidic functional groups, etc. can be listed. As the halogen group, fluorine groups, chlorine groups, bromine groups and iodine groups can be listed. As the acidic functional group, hydroxyl groups, carboxylic acid groups, sulfonic acid groups, sulfuric acid groups, phosphonic acid groups, phosphoric acid groups, phosphinic acid groups, maleic acid groups, anhydride groups (maleic anhydride groups, etc.), fumaric acid groups, itaconic acid groups, acrylic acid groups, methacrylic acid groups, mercapto groups, etc. can be listed. Among them, carboxylic acid groups (carboxyl groups) are preferred.

[0066] Examples of the nitrile oxide compound having a nitrile oxide group and an anionic group include compounds obtained by replacing the cationic group of the nitrile oxide compound having a nitrile oxide group and a cationic group with an anionic group.

[0067] Regarding the synthesis of the above-mentioned nitrile oxide compound having a nitrile oxide group and an anionic group, for example, first, a compound having a hydroxyl group and an aldehyde group is used as a starting material, and the compound having a hydroxyl group and an aldehyde group is reacted with a compound that can introduce an anionic group. If necessary, the group from the compound that can introduce an anionic group in the obtained substance is substituted with the anionic group. Then, the aldehyde group in the obtained compound is converted into a group represented by -CH=N-OH, and the group represented by -CH=N-OH is further converted into a group represented by -C≡N + -O- The group represented by can synthesize a nitrile oxide compound having a nitrile oxide group and an anionic group. Specifically, the nitrile oxide compound having a nitrile oxide group and an anionic group can be synthesized by the method described in WO2022 / 244317.

[0068] In the above-mentioned modified polymer (B), the method for making the above-mentioned nitrile oxide compound with nitrile oxide group and anionic group react with polymer can adopt any method that can react.For example, as required, the nitrile oxide compound and the polymer with unsaturated bond are dissolved or energy is given, thus cycloaddition reaction occurs between the carbon-carbon double bond in the main chain of the nitrile oxide group and the polymer, and the reaction of generating a five-membered ring can be carried out. Specifically, by the method described in WO2022 / 244317, the above-mentioned nitrile oxide compound with nitrile oxide group and anionic group is reacted with polymer, and the above-mentioned modified polymer (B) can be synthesized accordingly. In addition, by the above-mentioned method of mixing the polymer and the nitrile oxide compound under solvent-free conditions, the above-mentioned modified polymer (B) can also be synthesized.

[0069] The rubber composition contains the modified polymer (A) and, if necessary, the modified polymer (B) and other rubber components. Herein, the rubber component is generally a polymer having a weight average molecular weight (Mw) of 10,000 or more, and is a rubber component that cannot be extracted by acetone. The rubber component is in a solid state at room temperature (25° C.) and is a component that contributes to crosslinking.

[0070] In the rubber composition, examples of the rubber component include, in addition to the modified polymers (A) and (B), the polymers such as the diene rubber and the like.

[0071] The weight average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, further preferably 200,000 or more, particularly preferably 270,000 or more, and preferably 2,000,000 or less, more preferably 1,500,000 or less, further preferably 1,000,000 or less. When it is within the above range, there is a tendency to obtain better effects.

[0072] It should be noted that in this specification, the weight average molecular weight (Mw) can be obtained by conversion to standard polystyrene based on the measured value obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, chromatographic column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation). In addition, in the case of a polymer having a modified group, the modified group interacts with the silica gel of the chromatographic column and the correct Mw cannot be obtained, so the Mw is measured before the modification treatment is performed.

[0073] In the rubber composition, the content of the modified polymer (A) (a modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer) in 100% by mass of the rubber component is preferably 2% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, particularly preferably 15% by mass or more, and may be 100% by mass, 90% by mass or less, 85% by mass or less, or 80% by mass or less. Within the above range, there is a tendency to obtain a better effect. It should be noted that the content of the modified polymer (A) refers to the content of the modified polymer (A) in the case of a composition obtained by mixing a modified polymer (A) synthesized by reacting a nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer in advance by the above-mentioned production method and other components. In addition, when a polymer, a nitrile oxide compound having a nitrile oxide group and a cationic group and other components as required are kneaded under the above-mentioned kneading conditions and the polymer reacts with the nitrile oxide compound during kneading to produce the modified polymer (A), it refers to the total amount of the polymer and the nitrile oxide compound.

[0074] In the rubber composition, the content of the modified polymer (B) (modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and anionic groups with a polymer) in 100% by mass of the rubber component is preferably 2% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, particularly preferably 15% by mass or more, and may be 100% by mass, 90% by mass or less, 85% by mass or less, or 80% by mass or less. Within the above range, there is a tendency to obtain better effects. It should be noted that the content of the modified polymer (B) refers to the content of the modified polymer (B) in the case of a composition obtained by mixing a modified polymer (B) synthesized by reacting a nitrile oxide compound having a nitrile oxide group and anionic groups with a polymer in advance by the above-mentioned production method and other components. In addition, when a polymer, a nitrile oxide compound having a nitrile oxide group and anionic groups, and other components as required are kneaded under the above-mentioned kneading conditions, and the polymer reacts with the nitrile oxide compound during kneading to produce the modified polymer (B), it refers to the total amount of the polymer and the nitrile oxide compound.

[0075] When the rubber composition contains a modified SBR (A) obtained by reacting the nitrile oxide compound having a nitrile oxide group and a cationic group with SBR, the content of the modified SBR (A) is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more in 100% by mass of the rubber component, and is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. Within the above range, there is a tendency to obtain a better effect.

[0076] When the rubber composition contains a modified BR (A) obtained by reacting the nitrile oxide compound having a nitrile oxide group and a cationic group with BR, the content of the modified BR (A) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. Within the above range, there is a tendency to obtain better effects.

[0077] When the rubber composition contains a modified isoprene rubber (A) obtained by reacting the nitrile oxide compound having a nitrile oxide group and a cationic group with an isoprene rubber, the content of the modified isoprene rubber (A) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. Within the above range, there is a tendency to obtain better effects.

[0078] When the rubber composition contains a modified SBR (B) obtained by reacting the nitrile oxide compound having a nitrile oxide group and anionic groups with SBR, the content of the modified SBR (B) is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more in 100% by mass of the rubber component, and is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. Within the above range, there is a tendency to obtain a better effect.

[0079] When the rubber composition contains a modified BR (B) obtained by reacting the nitrile oxide compound having a nitrile oxide group and an anionic group with BR, the content of the modified BR (B) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. Within the above range, there is a tendency to obtain better effects.

[0080] When the rubber composition contains a modified isoprene rubber (B) obtained by reacting the nitrile oxide compound having a nitrile oxide group and anionic groups with an isoprene rubber, the content of the modified isoprene rubber (B) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 80% by mass or less. Within the above range, there is a tendency to obtain better effects.

[0081] It should be noted that, when one or more polymers, one or more nitrile oxide compounds having nitrile oxide groups and ionic groups (cationic groups or anionic groups), and other components as required are kneaded under the above-mentioned kneading conditions, and during kneading, each polymer reacts with each nitrile oxide compound to generate two or more modified polymers, the content of each modified polymer is: based on the content ratio of the two or more polymers and the content ratio of the two or more nitrile oxide compounds having nitrile oxide groups and ionic groups (cationic groups or anionic groups), the content of each modified polymer is proportionally distributed. For example, when two polymers (60 parts by mass of BR and 40 parts by mass of isoprene rubber) and 10 parts by mass of a nitrile oxide compound having a nitrile oxide group and a cationic group (polymer modifier) ​​are kneaded to generate modified BR and modified isoprene rubber during kneading, and a rubber composition containing these is produced, the ratio of the nitrile oxide compound having a nitrile oxide group and a cationic group that modifies BR is 6 parts by mass (=10×60 / (60+40)), and the content of the modified BR is 66 parts by mass (=60+6), the ratio of the nitrile oxide compound having a nitrile oxide group and a cationic group that modifies the isoprene rubber is 4 parts by mass (=10×40 / (60+40)), and the content of the modified isoprene rubber is 44 parts by mass (=40+4).

[0082] The rubber composition mentioned above contains a cross-linking agent. The crosslinking agent is not particularly limited as long as it is a compound that has the function of crosslinking the rubber component, and for example, sulfur, an organic crosslinking agent, an organic peroxide, a resin crosslinking agent, and other crosslinking agents known in the tire field can be used. Among them, sulfur is preferred from the perspective of obtaining a better effect.

[0083] In the above-mentioned rubber composition, the content of the crosslinking agent (the total amount of the crosslinking agent) is greater than 0 mass parts and less than 10 mass parts relative to 100 mass parts of the rubber component. The lower limit is preferably 0.6 mass parts or more, more preferably 0.9 mass parts or more, further preferably 1.2 mass parts or more, and particularly preferably 1.5 mass parts or more. The upper limit is preferably 5.0 mass parts or less, more preferably 3.0 mass parts or less, further preferably 2.5 mass parts or less, and particularly preferably 2.0 mass parts or less. When within the above range, there is a tendency to obtain a better effect.

[0084] As sulfur, powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are generally used as crosslinking agents in the rubber industry, can be cited. As commercially available products, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexsys Co., Ltd., Nippon Senryu Industry Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used. These can be used alone, or two or more can be used in combination.

[0085] In the rubber composition, the sulfur content is preferably 0.6 parts by mass or more, more preferably 0.9 parts by mass or more, further preferably 1.2 parts by mass or more, and particularly preferably 1.5 parts by mass or more, relative to 100 parts by mass of the rubber component, and is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, further preferably 2.5 parts by mass or less, and particularly preferably 2.0 parts by mass or less. Within the above range, there is a tendency to obtain better effects.

[0086] The organic crosslinking agent is not particularly limited, and examples thereof include maleimide compounds, alkylphenol-sulfur chloride condensates, organic peroxides, amine organic sulfides, etc. These may be used alone or in combination of two or more.

[0087] In the rubber composition, the content of the organic crosslinking agent is preferably 0.6 parts by mass or more, more preferably 0.9 parts by mass or more, further preferably 1.2 parts by mass or more, and particularly preferably 1.5 parts by mass or more, relative to 100 parts by mass of the rubber component, and is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, further preferably 2.5 parts by mass or less, and particularly preferably 2.0 parts by mass or less. When within the above range, there is a tendency to obtain better effects.

[0088] Examples of the organic peroxide include benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, methyl ethyl ketone peroxide, cumyl hydroperoxide, 2,5-dimethyl-2,5-di(tert-butyl peroxide)hexane, 2,5-dimethyl-2,5-bis(benzoyl peroxide)hexane, 2,5-dimethyl-2,5-di(tert-butyl peroxide)-3-hexyne, and 1,3-bis(tert-butyl peroxide isopropyl)benzene, etc. These may be used alone or in combination of two or more.

[0089] In the rubber composition, the content of the organic peroxide is preferably 0.6 parts by mass or more, more preferably 0.9 parts by mass or more, further preferably 1.2 parts by mass or more, and particularly preferably 1.5 parts by mass or more, relative to 100 parts by mass of the rubber component, and is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, further preferably 2.5 parts by mass or less, and particularly preferably 2.0 parts by mass or less. Within the above range, there is a tendency to obtain better effects.

[0090] The resin crosslinking agent is not particularly limited, and examples thereof include phenolic resins, melamine-formaldehyde resins, triazine-formaldehyde condensates, hexamethoxymethyl-melamine resins, alkylphenol-sulfur chloride condensates, etc. Among them, alkylphenol-sulfur chloride condensates are preferred from the viewpoint of the effects of the present invention.

[0091] The alkylphenol·sulfur chloride condensate is not particularly limited, but is preferably a compound represented by the following formula (II) from the viewpoint of achieving good low heat build-up properties, hardness, etc., and suppressing reversion.

[0092] (Where R 101 , R 102 and R 103 are the same or different and represent an alkyl group having 5 to 12 carbon atoms. x and y are the same or different and represent an integer of 1 to 3. k represents an integer of 0 to 250.

[0093] From the viewpoint of good dispersibility of the alkylphenol·sulfur chloride condensate in the rubber component, k is preferably an integer of 0 to 250, and more preferably an integer of 0 to 100. From the viewpoint of efficient high hardness, both x and y are preferably 2. From the viewpoint of good dispersibility of the alkylphenol·sulfur chloride condensate in the rubber component, R 101 ~R 103 An alkyl group having 6 to 9 carbon atoms is preferred.

[0094] The alkylphenol-sulfur chloride condensate can be prepared by a known method, for example, a method of reacting alkylphenol and sulfur chloride at a molar ratio of 1:0.9 to 1.25, etc. Specific examples of the alkylphenol-sulfur chloride condensate include TACKIROL V200 (the following formula (II-1)) manufactured by Taoka Chemical Industry Co., Ltd.

[0095] (In the formula, k represents an integer from 0 to 100.)

[0096] In the rubber composition, the content of the resin crosslinking agent is preferably 0.6 parts by mass or more, more preferably 0.9 parts by mass or more, further preferably 1.2 parts by mass or more, and particularly preferably 1.5 parts by mass or more, relative to 100 parts by mass of the rubber component, and is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, further preferably 2.5 parts by mass or less, and particularly preferably 2.0 parts by mass or less. When within the above range, there is a tendency to obtain better effects.

[0097] As commercially available crosslinking agents, products of Tsurumi Chemical Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexsys Co., Ltd., Nippon Senryu Kogyo Co., Ltd., Hosoi Chemical Co., Ltd., etc. can be used. These can be used alone or in combination of two or more.

[0098] The rubber composition contains carbon black. As carbon black, there is no particular limitation, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Co., Ltd., Shin Nichia Carbon Co., Ltd., and Columbia Carbon Co., Ltd. can be used. These can be used alone, or two or more can be used in combination.

[0099] The nitrogen adsorption specific surface area (N2SA) of carbon black is preferably 30 m 2 / g or more, more preferably 50m 2 / g or more, more preferably 70m 2 / g or more. In addition, the above N2SA is preferably 200m 2 / g or less, more preferably 150m 2 / g or less, more preferably 130m 2 / g or less, particularly preferably 120m 2 / g or less, and the most preferred is 111m 2When it is within the above range, there is a tendency for the effect to be better obtained. It should be noted that the N2SA of carbon black is determined in accordance with JIS K6217-2:2001.

[0100] In the rubber composition, the content of carbon black is greater than 0 mass parts and less than 100 mass parts relative to 100 mass parts of rubber components. The lower limit is preferably 3 mass parts or more, more preferably 5 mass parts or more, further preferably 7 mass parts or more, and particularly preferably 10 mass parts or more. The upper limit is preferably 50 mass parts or less, more preferably 30 mass parts or less, further preferably 25 mass parts or less, and particularly preferably 20 mass parts or less. When within the above range, there is a tendency to obtain a better effect.

[0101] Preferably, the rubber composition contains a filler (expander) other than carbon black. The filler is not particularly limited, and materials known in the rubber field can be used, for example, inorganic fillers such as silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica; biochar; poorly dispersible fillers, etc. Among them, silica is preferred from the perspective of obtaining a better effect.

[0102] In the rubber composition, the content of the filler (the total amount of fillers such as carbon black and silica) is preferably 2 parts by mass or more, more preferably 10 parts by mass or more, and further preferably 15 parts by mass or more, relative to 100 parts by mass of the rubber component, and 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. It should be noted that, in the present specification, the nitrile oxide compound having a nitrile oxide group and a cationic group is not included in the filler.

[0103] In the rubber composition, as the silica that can be used, dry process silica (anhydrous silica), wet process silica (hydrous silica) and the like can be cited. Among them, wet process silica is preferred because of the large number of silanol groups. As commercially available products, products of Degussa, Rhodia, Tosoh Silicon Chemical Co., Ltd., Solvay Japan Co., Ltd., Tokuyama Co., Ltd. and the like can be used. They can be used alone, or two or more can be used in combination.

[0104] As the silicon dioxide, silicon dioxide derived from plants can also be appropriately used. As the silica from plants, silica from plants containing silica components can be cited. As plants containing silica components, rice, corn, sugar cane, horsetail, wheat, barley, rye, rye, millet, foxtail millet, barnyard grass, awn, and sedge can be cited. In addition, saccharification residues of the above-mentioned plants containing silica components can also be used. Among them, rice husks and rice straws with high silica content are preferred, and rice husks are more preferred. In addition, plants containing silica components can be treated to ash by burning, or carbonization can be performed.

[0105] In the rubber composition, the content of silica is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and further preferably 15 parts by mass or more, relative to 100 parts by mass of the rubber component, and 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. Within the above range, there is a tendency to obtain better effects.

[0106] The nitrogen adsorption specific surface area (N2SA) of silicon dioxide is preferably 50 m 2 / g or more, more preferably 100m 2 / g or more, more preferably 150m 2 / g or more. In addition, the upper limit of N2SA of silica is not particularly limited, but is preferably 350 m 2 / g or less, more preferably 300m 2 / g or less, more preferably 250m 2 When it is within the above range, there is a tendency for the effect to be better obtained. It should be noted that the N2SA of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0107] Examples of the poorly dispersible filler include microfibrillated plant fibers, short-fiber cellulose, gel-like compounds, etc. Among them, microfibrillated plant fibers are preferred.

[0108] As the above-mentioned microfibrillated plant fiber, cellulose microfibrils are preferred from the perspective of obtaining good reinforcement. As cellulose microfibrils, there are no particular restrictions as long as they are cellulose microfibrils from natural objects. For example, cellulose microfibrils from resource biomass such as fruits, grains, root vegetables, wood, bamboo, hemp, jute, kenaf, and pulp or paper, cloth, crop waste, food waste, sewage sludge and other waste biomass obtained from them as raw materials, unused biomass such as rice straw, wheat straw, thinning materials, and cellulose produced by sea squirts, acetic acid bacteria, etc. can be listed. These microfibrillated plant fibers can be used in one kind, or in combination of two or more kinds.

[0109] It should be noted that, in this specification, cellulose microfibrils typically refer to cellulose fibers having an average fiber diameter of 10 μm or less, and more typically refer to cellulose fibers having a microstructure formed by an assembly of cellulose molecules and having an average fiber diameter of 500 nm or less. Typical cellulose microfibrils are formed, for example, as an assembly of cellulose fibers having the above-mentioned average fiber diameter.

[0110] When the rubber composition contains a poorly dispersible filler, the content of the poorly dispersible filler is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more, relative to 100 parts by mass of the rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, further preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less. Within the above range, there is a tendency to obtain better effects.

[0111] When the rubber composition contains silica, it is preferred that the rubber composition further contains a silane coupling agent. The silane coupling agent is not particularly limited, and any silane coupling agent known in the rubber field can be used. Examples thereof include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylbutyl)tetrasulfide, bis(trimethoxysilylethyl) 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 Sulfide-based products such as 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based products such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z manufactured by Momentive; ethylene The present invention relates to a vinyl-based silane such as triethoxysilane and vinyl trimethoxysilane; an amino-based silane such as 3-aminopropyl triethoxysilane and 3-aminopropyl trimethoxysilane; a glycidoxy-based silane such as γ-glycidoxypropyl triethoxysilane and γ-glycidoxypropyl trimethoxysilane; a nitro-based silane such as 3-nitropropyl trimethoxysilane and 3-nitropropyl triethoxysilane; a chlorine-based silane such as 3-chloropropyl trimethoxysilane and 3-chloropropyl triethoxysilane. As commercially available products, products of Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., AZmax Co., Ltd., Toray Dow Corning Co., Ltd., etc. can be used. These can be used alone or in combination of two or more.

[0112] In the rubber composition, the content of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and particularly preferably 7 parts by mass or more, relative to 100 parts by mass of silica. The upper limit of the content is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, further preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. When within the above range, there is a tendency to obtain a better effect.

[0113] The rubber composition mentioned above contains a plasticizer. In the present specification, the plasticizer is a material that imparts plasticity to the rubber component, and may be liquid or solid at room temperature (25° C.) These may be used alone or in combination of two or more. It should be noted that, in the present specification, the nitrile oxide compound having a nitrile oxide group and a cationic group is not included in the plasticizer.

[0114] Examples of the plasticizer include oils, liquid polymers, resins, etc. These may be used alone or in combination of two or more.

[0115] As the above-mentioned oil, there is no particular limitation, and the previously known oils such as paraffinic process oil, aromatic process oil, naphthenic process oil, low PCA (polycyclic aromatic) process oils such as TDAE and MES, oils from plants, and mixtures thereof can be used. They can be used alone, or two or more can be used in combination. It should be noted that, from the perspective of life cycle analysis, lubricating oils, waste cooking oils, etc. used in rubber mixing mixers, motor vehicle engines, etc. can be appropriately used.

[0116] Examples of the plant-derived oil (also referred to as vegetable oil) include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia oil, and tung oil.

[0117] As the above oil, for example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Nippon Energy Co., Ltd., Olisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Refining Co., Ltd., Showa Shell Sekiyu Co., Ltd., Fuji Kosan Co., Ltd., Nissin Oillio Group Co., Ltd., etc. can be used.

[0118] As the above-mentioned liquid polymer, for example, liquid diene polymers (liquid rubber) and liquid farnesene polymers at 25° C. can be cited. As liquid rubber, liquid styrene-butadiene copolymers (liquid SBR), liquid butadiene polymers (liquid BR), liquid isoprene polymers (liquid IR), liquid styrene-isoprene copolymers (liquid SIR), liquid styrene-butadiene-styrene block copolymers (liquid SBS block polymers), liquid styrene-isoprene-styrene block copolymers (liquid SIS block polymers) can be cited. The ends and main chains of these can be modified with polar groups. In addition, these hydrogenated products can also be used.

[0119] The weight average molecular weight (Mw) of the liquid diene polymer measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1.0×10 3 ~5.0×10 4 , more preferably 3.0×10 3 ~1.5×10 4In addition, the lower limit or upper limit of Mw of the liquid diene polymer may be 4,500 or 8,500. In addition, in this specification, Mw of a liquid diene polymer is a polystyrene conversion value measured by gel permeation chromatography (GPC).

[0120] As the liquid diene polymer, for example, products of Sartomer Co., Ltd., Kuraray Co., Ltd., etc. can be used.

[0121] As the above-mentioned resin, as a tire compound, a commonly used resin can be used, which can be liquid or solid at room temperature (25°C). For example, it can be listed: aromatic vinyl polymers, coumarone-indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, acrylic resins, etc. In addition, the resin can be a hydrogenated resin (hydrogenated resin). They can be used alone or in combination of two or more. In addition, the resin itself can be a copolymer from a variety of monomer components. Among them, aromatic vinyl polymers, petroleum resins, terpene resins, and their hydrogenated resins are preferred.

[0122] When a resin that is solid at room temperature is used, the softening point of the resin is preferably 50° C. or higher, more preferably 55° C. or higher, further preferably 60° C. or higher, and particularly preferably 85° C. or higher. In addition, 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 it is within the above range, there is a tendency that a better effect is obtained. When the resin is liquid at room temperature, the softening point is preferably 20° C. or lower, more preferably 10° C. or lower, and further preferably 0° C. or lower. In the case of hydrogenated resins, the softening point is preferably the same as above. The softening point of the resin is the softening point specified in JIS K6220-1:2001 measured using a ring and ball softening point measuring device, and is the temperature at which the ball falls.

[0123] The 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, and 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.

[0124] The coumarone-indene resin is a resin containing coumarone and indene as main monomer components constituting the resin skeleton (main chain). Examples of monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, and the like.

[0125] The coumarone resin is a resin containing coumarone as a main monomer component constituting the resin skeleton (main chain).

[0126] The indene resin is a resin containing indene as a main monomer component constituting the resin skeleton (main chain).

[0127] As the phenolic resin, for example, a known phenolic resin such as a polymer obtained by reacting phenols with aldehydes such as formaldehyde, acetaldehyde, and furfural using an acid or alkaline catalyst can be used. Among them, a phenolic resin obtained by reacting them using an acid catalyst (such as a novolac phenolic resin) is preferred.

[0128] Examples of the rosin resin include rosin-based resins represented by natural rosin, polymerized rosin, modified rosin, ester compounds thereof, and hydrogenated products thereof.

[0129] Examples of the petroleum resin include C5 resins, C9 resins, C5 / C9 resins, dicyclopentadiene (DCPD) resins, C9 / DCPD resins, and hydrogenates thereof, among which DCPD resins, hydrogenated DCPD resins, C9 / DCPD resins, and C9 / hydrogenated DCPD resins are preferred.

[0130] The above-mentioned terpene resin is a polymer containing terpene as a constituent unit. For example, polyterpene resins obtained by polymerizing terpene compounds, aromatic modified terpene resins obtained by polymerizing terpene compounds and aromatic compounds, etc. can be listed. As aromatic modified terpene resins, terpene phenol resins using terpene compounds and phenolic compounds as raw materials, terpene styrene resins using terpene compounds and styrene compounds as raw materials, and terpene phenol styrene resins using terpene compounds, phenolic compounds and styrene compounds as raw materials can also be used. It should be noted that as terpene compounds, α-pinene, β-pinene, etc. can be listed, as phenolic compounds, phenol, bisphenol A, etc. can be listed, and as aromatic compounds, styrene compounds (styrene, α-methylstyrene, etc.) can be listed. Among them, aromatic modified terpene resins are preferred.

[0131] The acrylic resin is a polymer containing an acrylic monomer as a constituent unit. For example, styrene acrylic resins such as styrene acrylic resins obtained by copolymerizing an aromatic vinyl monomer component and an acrylic monomer component having a carboxyl group can be cited. Among them, solvent-free styrene acrylic resins containing a carboxyl group can be preferably used.

[0132] 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 Company, ExxonMobil Corporation, KRATON, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0133] As the plasticizer, from the viewpoint of sustainability, it is preferred to use a plant-derived plasticizer such as the plant-derived oil or farnesene polymer.

[0134] Farnesene polymers are polymers obtained by polymerizing farnesene, and have structural units based on farnesene. Farnesene includes isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodetetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene), and (E)-β-farnesene having the following structure is preferred.

[0135] The farnesene polymer may be a homopolymer of farnesene (farnesene homopolymer), or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer). They may be used alone, or two or more may be used in combination. Among them, a copolymer of farnesene and a vinyl monomer is preferred.

[0136] As the vinyl monomer, styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethylether, 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 tertiary amino groups, butadiene, conjugated diene compounds such as isoprene, etc. can be listed. They can be used alone or in combination of two or more. Among them, butadiene is preferred. That is, as the farnesene-vinyl monomer copolymer, a copolymer of farnesene and butadiene (farnesene-butadiene copolymer) is preferred.

[0137] In the farnesene-vinyl monomer copolymer, the copolymerization ratio of farnesene to vinyl monomer (farnesene / vinyl monomer) based on mass is preferably 40 / 60 to 90 / 10.

[0138] Farnesene polymers having a weight average molecular weight (Mw) of 3000 or more and 300,000 or less can be used appropriately. The Mw of the farnesene polymer is preferably 8000 or more, more preferably 10000 or more, and preferably 100,000 or less, more preferably 60,000 or less, and further preferably 50,000 or less. Within the above range, there is a tendency to obtain better effects.

[0139] The farnesene polymer may be any of a farnesene polymer in a liquid state at room temperature (25° C.) or a farnesene polymer in a solid state. Among them, a liquid farnesene polymer in a liquid state at room temperature (25° C.) is preferred.

[0140] When the rubber composition contains a plasticizer, the content of the plasticizer (the total amount of the plasticizer) is preferably greater than 5 parts by mass relative to 100 parts by mass of the rubber component. The lower limit is preferably more than 10 parts by mass, more preferably more than 15 parts by mass, further preferably more than 20 parts by mass, and particularly preferably more than 25 parts by mass. The upper limit is preferably less than 100 parts by mass, more preferably less than 60 parts by mass, further preferably less than 50 parts by mass, particularly preferably less than 40 parts by mass, and most preferably less than 35 parts by mass. When within the above range, there is a tendency to obtain a better effect. It should be noted that the content of the plasticizer also includes the amount of oil and resin contained in the oil-extended rubber and the resin-filled rubber.

[0141] In the rubber composition, the content of the solid plasticizer in a solid state at room temperature (25° C.) is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and further preferably 7 parts by mass or more, relative to 100 parts by mass of the rubber component. The upper limit is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 12 parts by mass or less. Within the above range, there is a tendency to obtain better effects. In addition, the content of the above-mentioned resin in a solid state at room temperature (25° C.) is also preferably in the same range.

[0142] In the rubber composition, the content of the liquid plasticizer in a liquid state at room temperature (25° C.) is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, further preferably 20 parts by mass or more, and particularly preferably 25 parts by mass or more, relative to 100 parts by mass of the rubber component. The upper limit is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, further preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less, and most preferably 35 parts by mass or less. Within the above range, there is a tendency to obtain better effects. It should be noted that the content of the liquid plasticizer also includes the amount of oil contained in the oil-extended rubber and the amount of liquid resin in the resin-filled rubber filled with the liquid resin. The content of the oil that is liquid at room temperature (25° C.) is also preferably in the same range.

[0143] The rubber composition includes a temperature responsive material A, and the temperature responsive material A includes a polymer having a carboxyl group. Poly(N-isopropylacrylamide) (Poly(NIPAAm)) is known as a representative example of a temperature-responsive polymer. Poly(NIPAAm) shows a phenomenon in which it dissolves at low temperatures and precipitates at high temperatures (phase separation) in an aqueous solution, and has a lower critical solution temperature (LCST). In addition, it is known that a hydrogel of poly(N-isopropylacrylamide) undergoes a volume phase transition.

[0144] On the other hand, the temperature-responsive material A containing a polymer having a carboxyl group also has the characteristics of a temperature-responsive hydrogel, and preferably has the following properties. (1) When the liquid is less than the LCST, it is transparent; when the liquid is greater than the LCST, it is phase separated and becomes turbid. (2) It is soft when it is below LCST, and shows high strength and high toughness when it is above LCST. When it is above LCST, the elastic modulus and toughness increase with the higher temperature, but above a certain temperature, due to strong phase separation, the elastic modulus rises sharply (becomes extremely hard) and the toughness decreases. (3) Before and after LCST, the volume change is almost zero, and no volume phase change is shown. In the hydrogel of the present invention, no volume phase change or substantially no volume change means that the ratio V2 / V1 of the volume V2 at a temperature greater than LCST (e.g., T2 ≥ LCST + 5°C) to the volume V1 at a temperature less than LCST (e.g., T1 ≤ LCST - 5°C) is in the range of 0.8 to 1.2, preferably in the range of 0.85 to 1.15, and more preferably in the range of 0.98 to 1.02. (4) The temperature-responsive phase separation is completely reversible.

[0145] The above-mentioned polymer with carboxyl group is not particularly limited as long as it is an organic macromolecular compound with carboxyl group, and for example, a homopolymer (homopolymer) of a monomer with carboxyl group, a copolymer (copolymer) of a variety of monomers containing a monomer with carboxyl group, etc. can be enumerated. They can be used alone, or can be used in combination with more than two kinds.

[0146] Examples of the monomer having a carboxyl group include α,β-unsaturated carboxylic acids having one or more carboxyl groups in the molecule. Examples of the α,β-unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, aconitic acid, fumaric acid, and crotonic acid.

[0147] The homopolymer is not particularly limited, and examples thereof include polyacrylic acid and polymethacrylic acid.

[0148] As the copolymer, copolymers formed from a plurality of monomers having a carboxyl group, copolymers of a monomer having a carboxyl group and other monomers other than the monomer having a carboxyl group, etc. can be cited. There is no particular limitation on other monomers other than the monomer having a carboxyl group, for example, acrylate monomers (for example, α, β-ethylenically unsaturated carboxylic acid esters, hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids, alkoxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids), acrylamide monomers, styrene monomers, etc. can be cited. They can be used alone or in combination of two or more.

[0149] The above-mentioned acrylic acid ester monomers are not particularly limited, and examples thereof include α,β-ethylenically unsaturated carboxylates such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, lauryl acrylate, and stearyl acrylate; hydroxyalkyl esters of α,β-ethylenically unsaturated carboxylic acids such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 3-hydroxypropyl methacrylate; and alkoxyalkyl esters of α,β-ethylenically unsaturated carboxylic acids such as diethylene glycol methacrylate.

[0150] The acrylamide-based monomer is not particularly limited, and examples thereof include acrylamide and methylol acrylamide.

[0151] The styrene-based monomer is not particularly limited, and examples thereof include styrene and alkylstyrene.

[0152] From the perspective of temperature responsiveness, in the above-mentioned copolymer, the content of the structural unit from the monomer having a carboxyl group is preferably 50 mol% or more. The content is preferably 60 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, and particularly preferably 90 mol% or more. In addition, the upper limit is not particularly limited, for example, preferably 98 mol% or less, more preferably 95 mol% or less.

[0153] From the perspective of temperature responsiveness, the content of carboxyl groups in the above-mentioned polymer having carboxyl groups is preferably 0.001 mol / g or more, more preferably 0.005 mol / g or more, and further preferably 0.007 mol / g or more. In addition, it is preferably 0.05 mol / g or less, more preferably 0.03 mol / g or less, and further preferably 0.014 mol / g or less.

[0154] The above-mentioned polymer having a carboxyl group may have a cross-linked structure. Examples of the crosslinked structure include a chemical crosslinked structure, a physical crosslinked structure, etc. The chemical crosslinked structure can be formed by crosslinking with a crosslinking agent for forming chemical crosslinks during or after the formation of the polymer. It should be noted that, in the present invention, a crosslinking agent for forming chemical crosslinks is not included in the above-mentioned crosslinking agents.

[0155] As a crosslinking agent for chemical crosslinking formation for forming a chemical crosslinking structure, a monomer with more than two functionalities can be used. As a crosslinking agent, for example, N,N'-methylenebisacrylamide (MbAAd), N,N'-ethylenebisacrylamide, diethylene glycol diacrylate, diethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, 1-acryloyloxy-3-methacryloyloxy-2-propanol, etc. can be listed. Regarding the amount of the crosslinking agent for chemical crosslinking formation, according to the desired degree of crosslinking, relative to the concentration of the monomer, for example, it can be set in the range of 0 to 10 mol%.

[0156] The weight average molecular weight of the polymer having a carboxyl group is not particularly limited, and is, for example, 1,000,000 or less, and more preferably 500,000 or less. The lower limit is, for example, 5,000 or more, and preferably 10,000 or more. However, it is virtually impossible to measure the average molecular weight of a polymer having a cross-linked structure.

[0157] The physical crosslinking structure is formed, for example, by forming a salt between two carboxyl groups and one divalent metal possessed by a polymer having a carboxyl group and / or by polymer entanglement. The former physical crosslinking structure is formed by forming a salt based on a divalent metal on a polymer formed without using a crosslinking agent for chemical crosslinking. The phenomenon that the physically cut hydrogel rejoins after cutting is mainly caused by the formation of a salt between a carboxyl group and a divalent metal. Among them, it is speculated that since polymer entanglement is also carried out over a relatively long period of time, the rejoining caused by salt formation is further enhanced. In addition, with respect to the hydrogel having a chemical crosslinking structure, since the two carboxyl groups possessed by the polymer form a salt with one divalent metal, and there is also entanglement of the polymer, it also has a physical crosslinking structure.

[0158] As the polymerization method for preparing the polymer, free radical polymerization (thermal polymerization) based on a thermal initiator and photopolymerization based on a photoinitiator can be cited. Among them, photopolymerization is preferred. As a polymerization initiator, a known initiator can be used appropriately. As a photoinitiator, for example, α-ketoglutaric acid can be cited. The concentration relative to the initiator and the monomer can be set in the range of 0.01 to 10 mol%, for example.

[0159] Preferably, the temperature responsive material A contains a metal salt. The metal salt is not particularly limited, but is preferably an organic acid metal salt, and more preferably an organic acid divalent metal salt, from the viewpoint of obtaining a better effect.

[0160] The organic acid constituting the organic acid divalent metal salt is not particularly limited, and examples thereof include fatty acids (aliphatic carboxylic acids), aromatic carboxylic acids, oxocarboxylic acids, and other organic acids.

[0161] Examples of the fatty acid (aliphatic carboxylic acid) include the following compounds. ·Formic acid / methanoic acid ·Acetic acid / ethanoic acid ·Propionic acid / propanoic acid ·Butyric acid [butyric acid / butanoic acid] Isobutyric acid ·Valeric acid / pentanoic acid Isovaleric acid ·Caproic acid [caproic acid / hexanoic acid] ·Heptanoic acid [enanthic acid / heptanoic acid] · Caprylic acid / octanoic acid ·Pelargonic acid / nonanoic acid ·Capric acid / decanoic acid ·Lauric acid / dodecanoic acid ·Myristic acid / tetradecanoic acid ·Pentadecylic acid / pentadecanoic acid ·Palmitic acid[palmitic acid / hexadecanoic acid] ·Pearl fatty acid [margaric acid / heptadecanoic acid] ·Stearic acid / octadecanoic acid Oleic acid Linoleic acid Linolenic acid ·Tuberculostearic acid / nonadecanoic acid ·Arachidic acid / icosanoic acid Arachidonic acid Eicosapentaenoic acid ·Behenic acid / docosanoic acid Docosahexaenoic acid ·Lignoceric acid / tetracosanoic acid ·Cerotic acid / hexacosanoic ·Montanic acid / octacosanoic acid Melissic acid / triacontanoic acid

[0162] Examples of the aromatic carboxylic acid include the following compounds. Salicylic acid [hydroxybenzoic acid] Gallic acid (trihydroxybenzoic acid) ·Benzoic acid [Benzenecarboxylic acid] Phthalic acid Cinnamic acid (β-phenyl acrylic acid) ·Mellitic acid (mellitate, graphite) [Melitic acid]

[0163] Examples of the oxocarboxylic acid include the following compounds. Pyruvic acid (oxopyruvic acid, α-ketopyruvic acid, pyrogluconic acid)

[0164] As other organic acids, the following compounds can be mentioned. ·Oxalic acid Lactic acid (α-hydroxypropionic acid) ·tartaric acid Maleic acid Fumaric acid (fumaric acid, allomalic acid, boletic acid, lichenic acid) ·Propanedioic acid Succinic acid Malic acid (hydroxysuccinic acid) Citric acid ·Aconitic acid Glutaric acid ·Hexanedioic acid Amino Acids L-Ascorbic Acid (Vitamin C)

[0165] Among the above-mentioned organic acids, formic acid, acetic acid, and propionic acid are preferred in consideration of the solubility and solubility curve of the salt in the hydrogel in the aqueous solution. For example, calcium formate exhibits a relatively small positive solubility curve in the range of 0 to 100°C as a function of temperature (the solubility increases when the temperature rises). In contrast, calcium acetate exhibits a negative solubility curve in the range of 0°C to about 60°C as a function of temperature, and exhibits a relatively small positive solubility curve in the range of about 50°C to about 85°C. Calcium propionate exhibits a negative solubility curve in the range of 0°C to about 50°C as a function of temperature, and exhibits a positive solubility curve in the range of about 50°C to 100°C.

[0166] The divalent metal constituting the divalent metal salt of an organic acid is not particularly limited, and is preferably an alkaline earth metal, such as calcium (Ca), magnesium (Mg), strontium (Sr), and barium (Ba).

[0167] From the viewpoint of obtaining better effects, among the above organic acid divalent metal salts, Ca formate, Ca acetate, Ca propionate, Mg formate, Mg acetate, Mg propionate, etc. are preferred. The LCST of the hydrogel can be changed depending on the type of organic acid divalent metal salt used.

[0168] The total metal concentration in the above-mentioned temperature-responsive material A can be measured, for example, by inductively coupled plasma atomic emission spectroscopy (ICP). By sintering a known volume of temperature-responsive material A (for example, about 1000°C), removing the organic components, dissolving the residue in a known amount of water, and measuring the aqueous solution by ICP, the concentration of the metal can be determined. It should be noted that, in the case where the temperature-responsive material A contains a divalent metal salt of an organic acid, the concentration of free metal in the temperature-responsive material A that has not formed an organic acid salt can be measured, for example, using a metal ion electrode. In the case where metal ions that form organic acid salts and free metal ions exist in the temperature-responsive material A, this method can be used to distinguish between the two.

[0169] In the case where the temperature responsive material A contains a divalent metal salt of an organic acid, the concentration of the divalent metal salt of an organic acid in the temperature responsive material A can be appropriately determined in consideration of the physical properties required for the temperature responsive hydrogel and the amount of carboxyl groups. The concentration of the aqueous metal salt solution immersed in the polymer is, for example, in the range of 50 mM to saturation concentration, preferably in the range of 50 to 500 mM. Saturation concentration refers to the saturated amount (equivalent amount) relative to the amount of carboxyl groups in the polymer. The LCST of the hydrogel can be changed by the concentration of the metal salt relative to the polymer. The concentration of the metal relative to the polymer tends to be higher than the metal concentration of the aqueous metal salt solution immersed in the polymer, and varies according to conditions such as the carboxyl group concentration in the polymer and the concentration of the metal salt in the aqueous solution. For example, it is sometimes about 1.1 to 2.0 times higher, and more typically about 1.2 to 1.5 times higher. When the divalent metal is calcium, the concentration of the divalent metal relative to the polymer is, for example, in the range of about 1 to 100 mg, more typically about 10 to 70 mg, and even more typically about 15 to 50 mg per 1 g of the polymer (gel).

[0170] The above-mentioned polymer having a carboxyl group, and the temperature-responsive material A (hydrogel) containing a metal salt as required, is a gel with water or an aqueous solution and a polymer as the main components. Whether the above-mentioned polymer forms a hydrogel depends mainly on the length of the polymer (in other words, the concentration of the polymerization initiator). Even if the polymer mass is the same, if the concentration of the polymerization initiator is high, the tendency to gel will also become higher. From this perspective, with respect to the polymerization initiator, for example, when the monomer is acrylic acid, when the concentration is 0.1 mol%, there is a tendency to gel at 3M or more, and when the concentration is 0.01 mol%, there is a tendency to gel at 2M or more. In the case where the monomer is methacrylic acid, it is also roughly the same degree. The concentration of the polymerization initiator can be appropriately selected within the range of forming a hydrogel according to the type of polymerization initiator and the type of monomer.

[0171] The temperature-responsive material A (hydrogel) has a lower critical solution temperature (LCST). LCST is the lower critical solution temperature at which white turbidity is produced due to phase separation of the hydrogel, and serves as an indicator of the phase separation temperature. Having LCST can be evaluated, for example, by measuring turbidity (transmittance) using an ultraviolet-visible-near-infrared spectrophotometer. In addition, it can also be evaluated by measuring the exothermic peak by a differential scanning calorimeter, or by measuring the temperature dependence of the dynamic elastic modulus by a rheometer (viscoelasticity measuring device). The LCST of the above-mentioned temperature-responsive material A (hydrogel) varies depending on the composition of the polymer, the type and concentration of the metal salt, for example, in the range of 10 to 80°C, preferably in the range of 25 to 45°C.

[0172] The temperature responsive material A (hydrogel) is transparent in a temperature range below LCST and is turbid in a temperature range above LCST. Transparency in the present invention means that the transmittance at a wavelength of 550nm is 85% or more, and turbid means that the transmittance at a wavelength of 550nm is 30% or less.

[0173] The temperature-responsive material A (hydrogel) containing a polymer having a carboxyl group can be manufactured, for example, by immersing the polymer having a carboxyl group in water. In addition, the temperature-responsive material A (hydrogel) containing a polymer having a carboxyl group and a metal salt can be manufactured, for example, by immersing the polymer having a carboxyl group in an aqueous solution of the metal salt. The immersion of the polymer in water or an aqueous solution of a metal salt can be carried out at room temperature, for example, at a temperature in the range of 4 to 30° C. However, considering the LCST of the obtained temperature-responsive hydrogel, it can be carried out at a temperature higher or lower than the LCST.

[0174] The concentration of the metal salt in the aqueous solution of the above-mentioned metal salt can be appropriately determined in consideration of the types of polymer and metal salt and the desired LCST, for example, in the range of 50 mM to saturation concentration. For example, by immersing in an aqueous solution containing a metal salt at a concentration of 50 mM to saturation until it is approximately in equilibrium, a temperature-responsive hydrogel can be obtained. Regarding the immersion time, in the case of a chemically cross-linked gel, for example, it is approximately in equilibrium in about 1 to 72 hours, and in the case of a physically cross-linked gel, it is approximately in equilibrium in 2 to 7 days. However, if the desired physical properties can be obtained, it is sometimes not necessary to immerse until equilibrium.

[0175] From the perspective of obtaining a better effect, preferably, the temperature responsive material A is a material having at least a portion of a foamed structure. As long as at least a portion of the temperature responsive material A has a foamed structure, a portion of the temperature responsive material A may have a foamed structure, or the entire temperature responsive material A may have a foamed structure. By setting the temperature responsive material A to be a material having at least a portion of a foamed structure, the space in the void portion where water originally existed can be used to swell, thereby preventing the temperature responsive material A from swelling and increasing in volume when absorbing water, thereby further improving the hardness of the rubber composition when dried.

[0176] The material having at least a portion of a foamed structure is obtained by further processing the hydrogel into a foamed structure. The material is obtained by foaming the hydrogel and at least a portion of the hydrogel has a foamed structure containing a large number of bubbles. As a method for processing the hydrogel into a foamed structure, as long as a material having at least a portion of a foamed structure can be obtained, there is no particular limitation on the method, as long as it is foamed by a known method. For example, the method includes: heating the temperature-responsive material A (hydrogel) and then rapidly cooling and freezing it (for example, within 1 hour, preferably within 30 minutes, more preferably within 10 minutes, and particularly preferably within 5 minutes) by liquid nitrogen, etc., and freeze-drying the material. The heating conditions are not particularly limited as long as the temperature-responsive material A (hydrogel) phase separates. For example, the heating temperature is preferably 60° C. or higher, more preferably 80° C. or higher, and preferably 120° C. or lower, more preferably 100° C. or lower. The heating time is preferably 1 minute or longer, more preferably 5 minutes or longer, and preferably 24 hours or shorter, more preferably 10 hours or shorter, and even more preferably 1 hour or shorter. In addition, as the drying time of above-mentioned freeze drying, there is no particular restriction, for example, preferably more than 1 hour, more preferably more than 5 hours, further preferably more than 10 hours, particularly preferably more than 24 hours. In addition, preferably less than 72 hours, more preferably less than 48 hours, further preferably less than 30 hours. In addition, as a method for processing the hydrogel into a foamed structure, there are also methods of adding a foaming agent such as an inorganic foaming agent such as sodium bicarbonate and ammonium carbonate, and an organic foaming agent such as azodicarbonamide, dinitrosopentamethylenetetramine, and p,p'-oxybisbenzenesulfonylhydrazine to foam it.

[0177] In the rubber composition, the content of the temperature responsive material A is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, further preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more, relative to 100 parts by mass of the rubber component. The upper limit is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, further preferably 50 parts by mass or less, and particularly preferably 40 parts by mass or less. Within the above range, there is a tendency to obtain a better effect. It should be noted that in the present invention, the content of temperature responsive material A refers to the amount of a temperature responsive hydrogel (a gel with water or an aqueous solution and a polymer as main components) containing a polymer having a carboxyl group and a metal salt as required, and in addition to the polymer having a carboxyl group and the metal salt as required, it also includes the amount of water contained in the temperature responsive material (temperature responsive hydrogel).

[0178] From the viewpoint of obtaining better effects, the rubber composition preferably contains a water-soluble and / or water-absorbent material B. It should be noted that in the present invention, the water-soluble and / or water-absorbent material B refers to a material that is separately blended from the temperature-responsive material A containing the polymer having a carboxyl group and, if necessary, a metal salt, etc. That is, for example, when the temperature-responsive material A contains a temperature-responsive hydrogel containing polyacrylic acid and calcium acetate, and the water-soluble and / or water-absorbent material B contains calcium acetate monohydrate, the calcium acetate constituting the temperature-responsive material A does not belong to the water-soluble and / or water-absorbent material B, and the separately blended calcium acetate monohydrate belongs to the water-soluble and / or water-absorbent material B.

[0179] Among the above-mentioned water-soluble and / or water-absorbent materials B, the water-soluble material B (hereinafter, also referred to as "water-soluble material") is not particularly limited, and known water-soluble materials can be used. For example, a material having a solubility in water of 25 g / 100 g water or more at 20°C can be used. Among them, from the perspective of obtaining a better effect, the above-mentioned metal salts and their hydrates are preferred, and the above-mentioned organic acid divalent metal salts and their hydrates are more preferred. The organic acid and divalent metal constituting the organic acid divalent metal salt can also be listed as the same compounds as above. Hydrates that can be formed by metal salts such as monohydrates and dihydrates can be appropriately used.

[0180] Among the above water-soluble materials, alkaline earth metal salts of organic acids and hydrates thereof are preferred from the viewpoint of obtaining better effects, and Ca formate, Ca acetate, Ca propionate, Mg formate, Mg acetate, Mg propionate and hydrates thereof are more preferred.

[0181] Among the water-soluble and / or water-absorbent materials B, the water-absorbent material B (hereinafter also referred to as "water-absorbent material") is not particularly limited, and a known water-absorbent material can be used. For example, a material having a water absorption rate of 5% or more calculated by the following measurement method can be used. (Measurement method) When immersed in water at 20° C. for 24 hours, the weight before and after the immersion was measured, and the water absorption rate was calculated according to the following formula. Water absorption (%) = (weight after immersion - weight before immersion) / weight after immersion × 100

[0182] Examples of the water-absorbing material include materials having a heteroatom (fiber, elastomer, resin). Heteroatoms refer to atoms other than carbon atoms and hydrogen atoms, and are not particularly limited as long as they can undergo reversible molecular bonding such as hydrogen bonding and ionic bonding with water. They are preferably at least one atom selected from oxygen atoms, nitrogen atoms, silicon atoms, sulfur atoms, phosphorus atoms and halogen atoms, more preferably oxygen atoms, nitrogen atoms and silicon atoms, and still more preferably oxygen atoms.

[0183] Examples of the oxygen atom-containing structure and group include ether groups, ester groups, carboxyl groups, carbonyl groups, alkoxy groups, and hydroxyl groups, among which ether groups are preferred and oxyalkylene groups are more preferred. Examples of the nitrogen atom-containing structure or group include amino groups (primary amino groups, secondary amino groups, and tertiary amino groups), amide groups, nitrile groups, and nitro groups, among which amino groups are preferred, and tertiary amino groups are more preferred. Examples of the structure or group containing a silicon atom include a silyl group, an alkoxysilyl group, and a silanol group, among which a silyl group is preferred, and an alkoxysilyl group is more preferred. Examples of the sulfur atom-containing structure and group include a sulfide group, a sulfate group, a sulfate ester, and a sulfone group. Examples of the structure or group containing a phosphorus atom include a phosphoric acid group and a phosphoric acid ester group. Examples of the halogen atom-containing structure and group include halogenated groups such as a fluoro group, a chloro group, a bromo group, and an iodine group.

[0184] For example, since cellulose fibers have hydroxyl groups, cellulose fibers can be cited as water-absorbent fibers. As the cellulose fibers, cellulose microfibrils are preferred. As cellulose microfibrils, there are no particular restrictions as long as they are cellulose microfibrils derived from natural materials, and for example, cellulose microfibrils derived from resource biomass such as fruits, grains, and root vegetables, wood, bamboo, hemp, jute, kenaf, and pulp or paper, cloth, agricultural waste, food waste, waste biomass such as sewage sludge, unused biomass such as rice straw, wheat straw, and thinning materials, and cellulose produced by sea squirts, acetic acid bacteria, etc., can be cited. They can be used alone, or two or more can be used in combination.

[0185] As the water-absorbing elastomer, for example, an elastomer having an oxyalkylene group can be cited. As the elastomer, for example, an epoxide / allyl glycidyl ether copolymer, an amine / allyl glycidyl ether copolymer, a silyl / allyl glycidyl ether copolymer, etc. can be cited. These can be used alone or in combination of two or more.

[0186] Examples of the water-absorbing resin include polyvinyl alcohol, polyurethane, polyvinyl acetate, epoxy resin, cellulose resin, polyethylene glycol, sodium polyacrylate, etc. These may be used alone or in combination of two or more.

[0187] In the rubber composition, relative to 100 parts by mass of the rubber component, the content of the water-soluble and / or water-absorbent material B (the total content of the water-soluble material and the water-absorbent material) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, further preferably 15 parts by mass or more, and particularly preferably 20 parts by mass or more. The upper limit is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, further preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less, and most preferably 30 parts by mass or less. When within the above range, there is a tendency to obtain a better effect. In the case of containing any one of the water-soluble material and the water-absorbent material, the amount is also preferably in the same range. In the present invention, the content of the water-soluble and / or water-absorbent material B refers to the total content of the water-soluble material and the water-absorbent material, and when the water-soluble material or the water-absorbent material is a hydrate, the content also includes the hydrate.

[0188] From the perspective of crack resistance, ozone resistance, etc., preferably, the rubber composition contains an antioxidant.

[0189] The antioxidant is not particularly limited, and examples thereof include naphthylamine antioxidants such as phenyl-α-naphthylamine; diphenylamine antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine antioxidants such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and N,N'-di-2-naphthyl-p-phenylenediamine; quinoline antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol antioxidants such as 2,6-di-tert-butyl-4-methylphenol and styrenated phenol; bisphenol, triphenol and polyphenol antioxidants such as tetrakis-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane; and the like. Among them, p-phenylenediamine antioxidants and quinoline antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., Flexsys Co., Ltd., etc. can be used.

[0190] In the rubber composition, 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 3.4 parts by mass or more, relative to 100 parts by mass of the rubber component. The content is preferably 10.0 parts by mass or less, and more preferably 6.0 parts by mass or less.

[0191] Preferably, the rubber composition comprises stearic acid. In the rubber composition, the content of stearic acid is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the rubber component.

[0192] As stearic acid, conventionally known stearic acid can be used. For example, products of NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc. can be used.

[0193] Preferably, the rubber composition described above contains zinc oxide. In the rubber composition, the content of zinc oxide is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and is preferably 6.0 parts by mass or less, more preferably 4.0 parts by mass or less, based on 100 parts by mass of the rubber component.

[0194] As zinc oxide, conventionally known zinc oxide can be used, for example, products of Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0195] The above-mentioned rubber composition may contain wax. In the rubber composition, the wax content is preferably 0.5 parts by mass or more, more preferably 1.6 parts by mass or more, and is preferably 8.0 parts by mass or less, more preferably 5.0 parts by mass or less, based on 100 parts by mass of the rubber component.

[0196] The wax is not particularly limited, and petroleum wax, natural wax, etc. can be cited. In addition, synthetic wax obtained by purifying or chemically treating various waxes can also be used. These waxes can be used alone or in combination of two or more.

[0197] Examples of petroleum waxes include paraffin wax and microcrystalline wax. Examples of natural waxes include plant waxes such as candelilla wax, carnauba wax, wood wax, rice wax, and jojoba wax; animal waxes such as beeswax, lanolin, and spermaceti; mineral waxes such as ozokerite, ceresin, and petrolatum; and purified products thereof. Examples of commercially available products include products of Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Chemical Co., Ltd.

[0198] Preferably, the rubber composition comprises a vulcanization accelerator. In the rubber composition, the content of the vulcanization accelerator is not particularly limited, and can be freely determined according to the desired vulcanization speed and crosslinking density. It is preferably 0.1 parts by mass or more, more preferably 1.0 parts by mass or more, and further preferably 1.7 parts by mass or more relative to 100 parts by mass of the rubber component. The upper limit is preferably 8.0 parts by mass or less, more preferably 5.0 parts by mass or less, and further preferably 4.0 parts by mass or less.

[0199] The type of vulcanization accelerator is not particularly limited, and commonly used vulcanization accelerators can be used. Examples of the vulcanization accelerator include benzothiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazole sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-o-tolylguanidine, and o-tolylbiguanide. These may be used alone or in combination of two or more. Among them, sulfenamide-based, guanidine-based, and benzothiazole-based vulcanization accelerators are preferred.

[0200] The rubber composition may contain, in addition to the above components, compounding agents commonly used in the tire industry, such as a mold release agent.

[0201] The rubber composition can be produced, for example, by kneading the above-mentioned components using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanizing the mixture.

[0202] 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 of the mixed vulcanizing agent and the vulcanization accelerator can usually be subjected to 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.

[0203] The tire components to which the rubber composition is applied are not particularly limited, and may include any of the following tire components: captread, sidewall, base tread, bead apex, lap apex, inner liner, under tread, breaker topping, ply topping, etc. Among them, the captread may be preferably used from the viewpoint of excellent wet grip performance.

[0204] As the tire, pneumatic tires, non-pneumatic tires, etc. can be listed, among which pneumatic tires are preferred. In particular, it can be preferably used as summer tires (summer tires), winter tires (studless anti-skid tires, snow tires, studded anti-skid tires, etc.), all-season tires, etc. The tire can be used for passenger car tires, large passenger car tires, large SUV tires, trucks, buses and other heavy-duty tires, light truck tires, two-wheeled motor vehicle tires, racing tires (high-performance tires), etc. Among them, it can be preferably used for passenger car tires and light truck tires.

[0205] The tire can be manufactured by conventional methods using the above-mentioned rubber composition. For example, the tire can be manufactured by the following method: the rubber composition compounded with various materials is extruded into the shape of a tire component in an unvulcanized stage, and is molded together with other tire components on a tire molding machine by conventional methods to form an unvulcanized tire, and then the unvulcanized tire is heated and pressurized in a vulcanizer to manufacture the tire. [Example]

[0206] Hereinafter, examples (embodiments) considered to be preferable when implemented will be described, but the scope of the present invention is not limited to the embodiments.

[0207] <Synthesis of Nitrile Oxide Compound Having Nitrile Oxide Group and Cationic Group (CNO-Py)> pass Figure 1 Compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic group) was synthesized by the synthetic route shown.

[0208] (Compound S → Compound P1) Add a stirring bar to a three-necked flask, add 2-hydroxy-1-naphthaldehyde (compound S) and DMF (N,N-dimethylformamide), and stir to dissolve. Add K2CO3 to the above flask and stir for 1 hour. Add 2-(chloromethyl)pyridine hydrochloride to the above mixture and stir to dissolve. Heat the solution in an oil bath and react at 100°C. After 3 hours, cool the solution to room temperature, dilute with ethyl acetate, put into a separatory funnel, and separate with water and NaCl aqueous solution. Collect the organic layer, dry with MgSO4, and remove the solvent with an evaporator. The obtained crude product is recrystallized from ethanol to obtain compound P1.

[0209] (Compound P1 → Compound P2) Add a stirring bar to a beaker, add compound P1 and ethanol, and stir to dissolve. Add an aqueous solution of CH3COONa·3H2O and NH2OH·HCl to the beaker of P1 and react at room temperature for 4 hours. Then, add a large amount of water to the above reaction solution to precipitate compound P2. Collect the precipitate and dry it to obtain compound P2.

[0210] (Compound P2 → Compound P3) Compound P2 was dispersed in 2-propanol, and NaClO aqueous solution was added to the compound P2 solution in a dropping funnel at 0-5°C to react. After the addition was completed, the reaction was allowed to proceed for 1 hour, and a large amount of water was added to the solution to precipitate compound P3. The precipitate was collected and dried to obtain compound P3 (nitrile oxide compound having a nitrile oxide group and a cationic group, CNO-Py).

[0211] Based on the composite 1 H-NMR spectrum ( Figure 2 )、TGA( Figure 3 ) It can be seen that compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic group) was synthesized.

[0212] <Synthesis of Nitrile Oxide Compound Having Nitrile Oxide Group and Anionic Group (CNO-COOH)> pass Figure 6 Compound C4 (a nitrile oxide compound having a nitrile oxide group and an anionic group) was synthesized by the synthetic route shown.

[0213] (Compound S → Compound C1) First, a stirrer, 2-hydroxy-1-naphthaldehyde (compound S), K2CO3, DMF (N,N-dimethylformamide), and ethyl 6-bromohexanoate were added to a three-necked flask and stirred to dissolve. Then, the mixture was heated in an oil bath and reacted at 100°C for 3 hours. The mixture was cooled to room temperature and separated using ethyl acetate and water. The ethyl acetate layer was dried with MgSO4 and evaporated. The residue was recrystallized with hexane to obtain compound C1.

[0214] (Compound C1 → Compound C2) Compound C1 and LiOH were dissolved in a mixed solvent of THF:iPrOH:H2O=(4:2:1), and reacted overnight at room temperature. After the reaction was completed, hydrochloric acid was used for neutralization and evaporation was performed. The residue was diluted with water and added to a separatory funnel together with ethyl acetate for separation. The ethyl acetate layer was dried with MgSO4, evaporated to dryness, and then vacuum dried to obtain compound C2.

[0215] (Compound C2 → Compound C3) Add a stirring bar, compound C2 and ethanol to a 500 ml beaker and stir to dissolve. Add an aqueous solution of CH3COONa·3H2O and NH2OH·HCl to the compound C2 solution and react at room temperature for 4 hours to obtain a precipitate. Filter the mixture, collect the precipitate, and vacuum dry to obtain compound C3.

[0216] (Compound C3 → Compound C4) Add a stirrer, compound C3, and 2-propanol to a three-necked flask, place in an ice bath, and stir to disperse. Add NaClO aqueous solution to the flask using a dropping funnel at 0-5°C for reaction. After the reaction is completed, adjust the pH to about 5 with HCl, and add a large amount of water to precipitate compound C4. Recrystallize the precipitate with ethanol / water to obtain the target compound C4 (nitrile oxide compound having a nitrile oxide group and anionic group, CNO-COOH).

[0217] <Synthesis of Modified Polymer (A)> According to Table 1, the above-mentioned compound P3 (an oxynitrile compound having an oxynitrile group and a cationic group, CNO-Py) is added to SSBR or BR, kneaded at 70°C for 15 minutes, and reacted during kneading to obtain a modified polymer (A) (modified polymers (Py_SBR_K1, Py_SBR_K2, Py_SBR_K3, Py_BR_K1, Py_BR_K2, Py_BR_K3) obtained by reacting an oxynitrile compound having an oxynitrile group and a cationic group with a polymer).

[0218] <Synthesis of Modified Polymer (B)> According to Table 2, the above-mentioned compound C4 (an oxynitrile compound having an oxynitrile group and an anionic group, CNO-COOH) is added to SSBR or BR, kneaded at 70°C for 15 minutes, and reacted during kneading to obtain a modified polymer (B) (modified polymers (COOH_SBR_K1, COOH_SBR_K2, COOH_SBR_K3, COOH_BR_K1, COOH_BR_K2, COOH_BR_K3) obtained by reacting an oxynitrile compound having an oxynitrile group and an anionic group with a polymer).

[0219] <Synthesis of Modified Polymer (C)> According to Table 3, the above-mentioned compound P3 is added to SSBR or BR, kneaded at 70°C for 15 minutes, and then the above-mentioned compound C4 is added to the mixture, kneaded at 70°C for 15 minutes, and reacted during kneading to obtain modified polymers (C) (Py_COOH_SBR_K1, Py_COOH_SBR_K2, Py_COOH_SBR_K3, Py_COOH_BR_K1, Py_COOH_BR_K2, Py_COOH_BR_K3) modified with anions and cations.

[0220] In addition, the SBR and BR in Tables 1, 2, and 3 used the following materials. SBR (SSBR): HPR840 (S-SBR) manufactured by JSR Corporation BR: BR150B manufactured by Ube Industries, Ltd. (cis content: 96 mass%)

[0221] The double bond modification rates and nitrile oxide compound reaction rates in Tables 1, 2, and 3 are defined as follows and measured by the following methods. (Double bond modification rate (%)) = [the amount of carbon-carbon double bonds reacted with the nitrile oxide compound / (the amount of remaining carbon-carbon double bonds + the amount of carbon-carbon double bonds reacted with the nitrile oxide compound)] × 100 (Nitrile oxide compound reaction rate (%)) = (amount of nitrile oxide compound reacting with double bond / (amount of nitrile oxide compound added) × 100

[0222] (1) Double bond modification rate By IR measurement, 1 H-NMR determination and 13 C-NMR measurement was used to calculate the ratio of the nitrile oxide compound added to the carbon-carbon double bond in the polymer.

[0223] (2) Reaction rate of nitrile oxide compounds By IR measurement, 1 H-NMR determination and 13 It was obtained by C-NMR measurement.

[0224] [Table 1] Mixing results of CNO-Py and SBR / BR

[0225] [Table 2] Mixing results of CNO-COOH and SBR / BR

[0226] [Table 3]

[0227] Tables 1 and 2 show that the double bond modification rate of the modified polymer (B) (a modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an anionic group with a polymer) is 0.4 to 4.8%, and the nitrile oxide compound reaction rate is 20.0 to 27.8%. In contrast, the double bond modification rate of the modified polymer (A) (a modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer) is 2.2 to 15.5%, and the nitrile oxide compound reaction rate is 83.3 to 95.0%. By using a nitrile oxide compound having a nitrile oxide group and a cationic group, the double bond modification rate can be controlled while the nitrile oxide compound reaction rate is increased.

[0228] Table 3 shows that the double bond modification rate of the nitrile oxide compound having a nitrile oxide group and an anionic group is improved by using the nitrile oxide compound having a nitrile oxide group and a cationic group together with the nitrile oxide compound having a nitrile oxide group and an anionic group.

[0229] <Preparation of Rubber Composition> The following is a summary of the various chemicals used. NR:TSR20 BR: BR150B manufactured by Ube Industries, Ltd. (cis content: 98 mass%) SBR: Nipol SBR1502 manufactured by Japan Zeon Co., Ltd. (styrene content: 23.5 mass%) Carbon black: Seast N220 (N2SA: 111m 2 / g) Silicon dioxide: Ultrasil VN3 (N2SA: 175m 2 / g) Silane coupling agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa Oil: Diana Process NH-70S manufactured by Idemitsu Kosan Co., Ltd. Plasticizer: Ricon 150 (liquid butadiene polymer) manufactured by Sartomer Temperature-responsive material A: Preparation example 1 (polyacrylic acid / calcium acetate gel) CNO-Py: The above-mentioned nitrile oxide compound having a nitrile oxide group and a cationic group CNO-COOH: The above-mentioned nitrile oxide compound having a nitrile oxide group and an anionic group Antioxidant: Nocrac 6C manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: Made by NOF Corporation Zinc oxide: Zinc oxide No. 2 manufactured by Mitsui Mining and Smelting Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator CZ: Nocceler CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator DPG: Nocceler D manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0230] (Production Example 1) Referring to Advanced Materials 2020, 32, 1905878, temperature-responsive material A was manufactured by the following manufacturing method. In ultrapure water, 1.0 M acrylic acid (AAc), 1.0 mol % of initiator potassium peroxodisulfate and 1.0 mol % of crosslinker N,N'-methylenebisacrylamide (MbAAd) were dissolved to prepare a precursor aqueous solution. Here, when the concentration of the crosslinking agent is 0 mol %, a physically crosslinked gel is obtained, and when a crosslinking agent is added, a chemically crosslinked gel is obtained. The solution was poured into a mold of any shape and heated and polymerized at 60° C. for 6 hours in air to form a gel. The polymerized gel or high-viscosity body having no fluidity is immersed in a sufficient amount of an aqueous solution (the aqueous solution is prepared by dissolving calcium acetate prepared at a concentration of 1000 mM in ultrapure water) until equilibrium is reached, thereby obtaining a temperature-responsive material A.

[0231] (Manufacturing of rubber composition) According to the formulations shown in Tables 4 to 6, chemicals other than the temperature-responsive material A, CNO materials (CNO-COOH, CNO-Py), sulfur, and a vulcanization accelerator were kneaded at 130° C. for 5 minutes using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded product. The temperature responsive material A and the CNO material (CNO-COOH, CNO-Py) were added to the kneaded product, and the mixture was kneaded at 70° C. for 15 minutes to obtain a kneaded product. Sulfur and a vulcanization accelerator were added to the kneaded product, and kneaded at 70° C. for 4 minutes to obtain an unvulcanized rubber composition. The unvulcanized rubber composition was press-vulcanized at 170° C. for 12 minutes to obtain a vulcanized rubber composition.

[0232] The physical properties of the vulcanized rubber composition were measured and evaluated as follows. The results are shown in Tables 4 to 6. The reference comparative examples are shown below. Table 4: Comparative Example 1-1 Table 5: Comparative Example 2-1 Table 6: Comparative Example 3-1

[0233] <Rubber Strength> A dumbbell No. 7 test piece was prepared and subjected to a tensile test using a tensile tester (RTG-1210) manufactured by A&D Co., Ltd. at a test temperature of 23° C. and a tensile test speed of 200 mm / min to measure the following TB and EB. TB: It represents the strength at break TB (MPa) per unit cross-sectional area at the thinnest part (the dumbbell neck part located in the center) of the test piece. EB: The test piece was placed on a testing machine with a distance between chucks of 20 mm, and a tensile test was performed. The distance between chucks at break was measured, and the elongation at break EB (%) was calculated from the value given by the following formula. Distance between fixtures at break (mm) / initial distance between fixtures (20mm)×100 Furthermore, the fracture energy calculated as follows was obtained from the obtained TB and EB, and was expressed as an index with the value of the reference comparative example being 100. Fracture energy = TB × EB / 2 The larger the fracture energy, the better the fracture characteristics (durability).

[0234] [Table 4]

[0235] [Table 5]

[0236] [Table 6]

[0237] According to Tables 4 to 6, when SBR, BR, nitrile oxide compounds (cationic group, CNO-Py), nitrile oxide compounds (anionic group, CNO-COOH) and other materials are kneaded, CNO-Py modified SBR, CNO-Py modified BR, CNO-COOH modified SBR, and CNO-COOH modified BR are generated during kneading.

[0238] The present invention (1) is a rubber composition for a tire, comprising: A rubber component containing a modified polymer obtained by reacting a polymer having a nitrile oxide group and a cationic group with a polymer modifier; Cross-linking agent; Carbon black; Plasticizers; and a temperature-responsive material A, wherein the temperature-responsive material A contains a polymer having a carboxyl group, The content of the crosslinking agent is greater than 0 and less than 10 parts by mass, the content of the carbon black is greater than 0 and less than 100 parts by mass, and the content of the plasticizer is greater than 5 parts by mass, relative to 100 parts by mass of the rubber component.

[0239] The present invention (2) is the rubber composition for a tire according to the present invention (1), wherein the cationic group is an amino group.

[0240] The present invention (3) is the tire rubber composition according to the present invention (2), wherein the amino group is a pyridyl group.

[0241] The present invention (4) is a tire using the rubber composition of any combination of any one of the present inventions (1) to (3).

Claims

1. A rubber composition for a tire, characterized in that: The tire rubber composition comprises: A rubber component containing a modified polymer obtained by reacting a polymer having a nitrile oxide group and a cationic group with a polymer modifier; Cross-linking agent; Carbon black; Plasticizers; as well as a temperature-responsive material A, wherein the temperature-responsive material A contains a polymer having a carboxyl group, The content of the crosslinking agent is greater than 0 and less than 10 parts by mass, the content of the carbon black is greater than 0 and less than 100 parts by mass, and the content of the plasticizer is greater than 5 parts by mass, relative to 100 parts by mass of the rubber component.

2. The tire rubber composition according to claim 1, wherein The cationic group is an amino group.

3. The tire rubber composition according to claim 2, wherein The amino group includes -NH2, a substituted amino group and a cyclic amino group.

4. The tire rubber composition according to claim 2, wherein The amino group is a pyridyl group.

5. The tire rubber composition according to claim 1, wherein The content of the carbon black is 3 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the rubber component.

6. The rubber composition for a tire according to claim 1, wherein The content of the plasticizer is 100 parts by mass or less relative to 100 parts by mass of the rubber component.

7. The rubber composition for a tire according to claim 1, wherein In the rubber composition, a content of the temperature responsive material A is 5 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the rubber component.

8. The rubber composition for a tire according to claim 1, wherein In the rubber composition, a content of the temperature responsive material A is 10 parts by mass or more and 60 parts by mass or less relative to 100 parts by mass of the rubber component.

9. A tire, characterized in that: The rubber composition according to any one of claims 1 to 8 is used.

Images