Modified polymer, rubber composition, and tire

Abstract

To provide a modified polymer, a rubber composition and a tire capable of improving the overall performance of rubber breaking strength and compression set.SOLUTION: The present invention relates to a modified polymer obtained by reacting a nitrileoxide compound having a nitrileoxide group and an ionic functional group with a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a modified polymer, a rubber composition, and a tire. [Background technology]

[0002] Tires have traditionally been required to have various performance characteristics, such as low fuel consumption (see Patent Document 1). In addition, improvements in performance such as rubber strength and compression set are also desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-65240 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a modified polymer, a rubber composition, and a tire that can solve the above problems and improve the overall performance of rubber breaking strength and compression set. [Means for solving the problem]

[0005] The present invention relates to a modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing conjugated diene units and non-conjugated olefin units. [Effects of the Invention]

[0006] According to the present invention, the modified polymer is obtained by reacting a nitrile oxide compound having a nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit, and therefore the overall performance of rubber breaking strength and compression set can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 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 functional group. [Figure 2] 2 shows examples of 1H-NMR (proton NMR) spectra of compounds P1, P2, and P3 in the synthetic route of FIG. 1. [Figure 3] 1 shows an example of the results of thermogravimetric analysis during the synthesis of compound P3. [Figure 4] FIG. 1 is a schematic diagram illustrating an example of a method for synthesizing a nitrile oxide compound having a nitrile oxide group and an anionic functional group. [Figure 5] 5 shows examples of 1H-NMR (proton NMR) spectra of compounds C, D, and E in the synthetic route of FIG. 4. [Figure 6] 5 shows examples of IR spectra of compounds D and E in the synthetic route of FIG. 4. [Figure 7] This is an example of synthesis of a reaction product (modified polymer) between a nitrile oxide compound having a nitrile oxide group and an ionic functional group and a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit. [Figure 8] 8 is an example of a 1H-NMR (proton NMR) spectrum of a modified polymer in the synthesis route of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Modified polymer> The modified polymer is a modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit.

[0009] The reason why the above-mentioned effects are obtained is not entirely clear, but is presumed to be as follows. Multicomponent copolymers containing conjugated diene units and non-conjugated olefin units, such as hydrogenated styrene-butadiene copolymers, have high ozone resistance, and when the content of non-conjugated olefin units is high (such as when the hydrogenation rate is high), crystallinity is developed, resulting in high fracture strength, making them promising for use in sidewalls and other applications. However, the higher the content of non-conjugated olefin units, the lower the co-crosslinkability and the lower the permanent set tends to be.On the other hand, if the content of non-conjugated olefin units is reduced, the co-crosslinkability increases and the permanent set improves, but there is a problem that the crystallinity decreases and the breaking strength decreases. Therefore, it is thought that by introducing a nitrile oxide compound having a nitrile oxide group and an ionic functional group into a polymer, a network consisting of crosslinks due to hydrogen bonds without sulfur crosslinking is formed. Furthermore, when this network is combined with a conventional sulfur-crosslinked rubber, it is believed that a rubber composition consisting of two networks will result. Because crosslinks due to hydrogen bonds are weaker than sulfur crosslinks, when strong energy is applied, the hydrogen bonds, which are more easily broken than sulfur crosslinks, undergo sacrificial fracture, dissipating the input energy and preventing the sulfur crosslinks from breaking, which is thought to improve the breaking strength of the rubber.In addition, because multiple ionic functional groups can aggregate to function as crosslinking points, it is thought that good permanent set can be imparted to polymers with a high content of non-conjugated olefin units. Therefore, it is presumed that the use of the modified polymer improves the overall performance of rubber breaking strength and compression set.

[0010] The modified polymer is obtained by reacting a nitrile oxide compound (polymer modifier) ​​having a nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit.

[0011] In the nitrile oxide compound (polymer modifier) ​​having a nitrile oxide group and an ionic functional 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 two or more nitrile oxide groups.

[0012] [ka]

[0013] In the nitrile oxide compound having a nitrile oxide group and an ionic functional group, the ionic functional group may be a cationic functional group or an anionic functional group.

[0014] From the viewpoint of obtaining a better effect, the nitrile oxide compound having a nitrile oxide group and an ionic functional group preferably includes a nitrile oxide compound having a nitrile oxide group and a cationic functional group, and a nitrile oxide compound having a nitrile oxide group and an anionic functional group.

[0015] In this case, the reason why the above-mentioned effects are more effectively obtained is not entirely clear, but is presumed to be as follows. When a nitrile oxide compound having a nitrile oxide group and a cationic functional group and a nitrile oxide compound having a nitrile oxide group and an anionic functional group are used, it is believed that by introducing the nitrile oxide compound having a nitrile oxide group and an ionic functional group, which can interact with each other, into a polymer, a network consisting of crosslinks by hydrogen bonds without sulfur crosslinking is formed. It is believed that the crosslinks by hydrogen bonds prevent the destruction of the sulfur crosslinks, thereby improving the breaking strength of the rubber. Therefore, it is believed that the overall performance of the rubber breaking strength and compression set is significantly improved.

[0016] The ionic functional group is preferably introduced into the terminal of the nitrile oxide compound. The nitrile oxide compound may be a compound having one ionic functional group or two or more ionic functional groups. The ionic functional group in the nitrile oxide compound may be one type or two or more types. The nitrile oxide compound may be, for example, a nitrile oxide compound having a nitrile oxide group and a cationic functional group, a nitrile oxide compound having a nitrile oxide group and an anionic functional group, or a nitrile oxide compound having a nitrile oxide group, a cationic functional group, and an anionic functional group.

[0017] Examples of the cationic functional group include monovalent cationic groups such as amino, ammonium, and imino groups, as well as salts thereof. Examples of atoms or atomic groups constituting the salt include hydroxide ions, halogen ions, carboxylate ions, sulfonate ions, fluoride ions, cyanide ions, silicate ions, borate ions, and condensed phosphate ions. The amino group cited as an example of the cationic functional group is not limited to -NH2, but also includes substituted amino groups and cyclic amino groups. Examples of the substituted amino group include monoalkylamino, dialkylamino, monoarylamino, diarylamino, and alkylarylamino groups. Examples of the cyclic amino group include pyrrolidine group, piperidine group, piperazine group, morpholine group, pyrrole group, pyrazole group, imidazole group, pyridine group, pyridazine group, pyrimidine group, pyrazine group, oxazole group, isoxazole group, thiazole group, isothiazole group, pyrrolidone group, piperidone group, 3-morpholinone group, morpholinedione group, and substituted groups thereof, and examples of the substituent include halogen group, monovalent hydrocarbon group (alkyl group, alkenyl group, etc.).Among these, from the viewpoint of obtaining more effective, cyclic amino group is preferred, and pyridine group and substituted pyridine group are more preferred.

[0018] Typical optionally substituted pyridine groups include the following: 2-pyridyl, 3-pyridyl, 4-pyridyl: [ka] and the following -CH3 substituted 3-pyridines: [ka] Examples include:

[0019] Examples of the anionic functional group include a halogen group and an acidic functional group. Examples of the halogen group include a fluoro group, a chloro group, a bromo group, and an iodo group. Examples of the acidic functional group include a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a sulfate group, a phosphonic acid group, a phosphate group, a phosphinic acid group, a maleic acid group, an acid anhydride group (such as a maleic anhydride group), a fumaric acid group, an itaconic acid group, an acrylic acid group, a methacrylic acid group, and a mercapto group. Of these, a carboxylic acid group (carboxyl group) is preferred.

[0020] The nitrile oxide compound is not particularly limited as long as it is a compound having a nitrile oxide group and an ionic functional group, and examples thereof include compounds represented by the following formula: XC≡N + -O - (In the formula, X represents a monovalent hydrocarbon group containing an ionic functional group.)

[0021] X is not particularly limited as long as it is a monovalent hydrocarbon group containing an ionic functional group. Examples of the ionic functional group contained in X include the same as the ionic functional groups described above. The ionic functional group contained in X is preferably formed at the end of X, for example, so that X is a group represented by -(CH)-A (A: ionic functional group).

[0022] The monovalent hydrocarbon group in X (monovalent hydrocarbon group containing an ionic functional group) means a monovalent hydrocarbon group that constitutes the skeleton of X and in which an ionic functional group has been substituted with a hydrogen atom. For example, when X is a group represented by -(CH)-COOH (COOH: ionic functional group), the monovalent hydrocarbon group in X is -(CH)-H.

[0023] The monovalent hydrocarbon group for X includes substituted or unsubstituted monovalent hydrocarbon groups, which may be linear, branched, or cyclic, but are preferably cyclic. The monovalent hydrocarbon group for X may also contain a heteroatom. The substituent is not particularly limited, and examples thereof include known groups such as a hydroxyl group and a halogen group (such as -Cl or -Br). The heteroatom is not particularly limited, and examples thereof include oxygen and nitrogen. These substituents and heteroatoms may be present in one or more numbers.

[0024] The monovalent hydrocarbon group for X preferably has 3 or more carbon atoms, more preferably 6 or more carbon atoms, and preferably 30 or less, more preferably 26 or less, and even more preferably 20 or less carbon atoms.

[0025] Examples of the monovalent hydrocarbon group for X include a substituted or unsubstituted linear alkyl group, branched alkyl group, cyclic alkyl group, aryl group, and aralkyl group, which may contain a heteroatom. The monovalent hydrocarbon group for X may also be a group to which these substituted or unsubstituted linear alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, and aralkyl groups, which may contain a heteroatom, are bonded (such as a group to which a substituted or unsubstituted linear alkyl group, which may contain a heteroatom, and a substituted or unsubstituted aryl group, which may contain a heteroatom, are bonded).

[0026] In the monovalent hydrocarbon group represented by X, examples of substituted or unsubstituted linear or branched 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 groups containing these 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 groups containing these heteroatoms. Examples of substituted or unsubstituted aryl groups that may contain heteroatoms include phenyl, tolyl, xylyl, biphenyl, naphthyl, anthryl, phenanthryl, and groups containing these heteroatoms. Examples of the substituted or unsubstituted aralkyl group which may contain a heteroatom include a benzyl group, a phenethyl group, and groups containing these heteroatoms. Furthermore, examples of the monovalent hydrocarbon group for X include groups to which these groups are bonded (such as a group to which a substituted or unsubstituted pentyl group which may contain a heteroatom and a substituted or unsubstituted naphthyl group which may contain a heteroatom are bonded).

[0027] Among these, the monovalent hydrocarbon group for X is preferably a substituted or unsubstituted linear alkyl group which may contain a heteroatom, a substituted or unsubstituted aryl group which may contain a heteroatom, or a group in which a substituted or unsubstituted linear alkyl group which may contain a heteroatom is bonded to a substituted or unsubstituted aryl group which may contain a heteroatom.

[0028] The compound having the nitrile oxide group and the ionic functional group is preferably a compound having a cyclic structure, more preferably a compound having an aromatic ring. Specific examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, a triphenylene ring, a naphthacene ring, a biphenyl ring, a bisphenol ring, and a terphenyl ring (three benzene rings may be connected in any manner). Among these, a compound having a benzene ring or a naphthalene ring is preferred, and a compound having a naphthalene ring is more preferred.

[0029] Suitable examples of the nitrile oxide compound having the nitrile oxide group and an ionic functional group include compounds represented by the following formula (compounds having a naphthalene ring).

[0030] [ka] (In the formula, A represents a monovalent ionic functional group, and Y represents a substituted or unsubstituted divalent hydrocarbon group which may contain a heteroatom.)

[0031] Examples of A (monovalent ionic functional group) include the monovalent ionic functional groups described above.

[0032] Y (a substituted or unsubstituted divalent hydrocarbon group which may contain a heteroatom) may be linear, branched, or cyclic. Examples of the heteroatom and substituent in Y include the heteroatoms and substituents described above. Y may have one or two or more of these substituents or heteroatoms.

[0033] The divalent hydrocarbon group for Y preferably has 1 or more carbon atoms, more preferably 2 or more carbon atoms, and even more preferably 3 or more carbon atoms, and preferably has 20 or less carbon atoms, more preferably 12 or less carbon atoms, and even more preferably 10 or less carbon atoms.

[0034] Examples of Y (a substituted or unsubstituted divalent hydrocarbon group which may contain a heteroatom) include a substituted or unsubstituted alkylene group, alkenylene group, cycloalkylene group, cycloalkylalkylene group, arylene group, aralkylene group, and oxyalkylene group which may contain a heteroatom.

[0035] Examples of substituted or unsubstituted alkylene groups that may contain heteroatoms include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, octylene, nonylene, decylene, 1,2-propylene, and groups containing these heteroatoms. Examples of substituted or unsubstituted alkenylene groups that may contain heteroatoms include vinylene, 1-propenylene, 2-propenylene, and groups containing these heteroatoms. Examples of substituted or unsubstituted cycloalkylene groups that may contain heteroatoms include cyclohexylene and groups containing this heteroatom. Examples of substituted or unsubstituted cycloalkylalkylene groups that may contain heteroatoms include cyclohexylmethylene and groups containing this heteroatom. Examples of substituted or unsubstituted arylene groups that may contain heteroatoms include phenylene, tolylene, xylylene, and groups containing these heteroatoms. Examples of the substituted or unsubstituted aralkylene group which may contain a heteroatom include a benzylidene group and a group containing this heteroatom, etc. Examples of the substituted or unsubstituted oxyalkylene group which may contain a heteroatom include an oxyethylene group, an oxypropylene group, an oxybutylene group, an oxytetramethylene group, and groups containing these heteroatoms, etc.

[0036] The compound having a naphthalene ring represented by the above formula is one example of a preferred example, and the —C≡N + -O - The substitution positions of the group represented by -YA are not particularly limited, and may be any of the 1st to 8th positions. + -O - , -YA.

[0037] Next, a method for synthesizing the nitrile oxide compound having the above nitrile oxide group and ionic functional group will be described.

[0038] Hereinafter, an example of a method for synthesizing a nitrile oxide compound having a nitrile oxide group and an ionic functional group will be described, but the nitrile oxide compound is not limited to one obtained by such a synthesis method, and includes compounds obtained by any synthesis method that allows synthesis.

[0039] First, a compound having a hydroxyl group and an aldehyde group is used as a starting material, and the compound having the hydroxyl group and the aldehyde group is reacted with a compound into which an ionic functional group can be introduced. If necessary, the group derived from the compound into which an ionic functional group can be introduced in the resulting substance is substituted with the ionic functional group.

[0040] Next, the aldehyde group in the prepared compound is converted to a group represented by -CH=N-OH, and the group represented by -CH=N-OH is further converted to -C≡N + -O - By converting the nitrile oxide compound into a group represented by the formula (I), a nitrile oxide compound having a nitrile oxide group and an ionic functional group can be synthesized.

[0041] The reaction process may be carried out in an organic solvent, in water, or without a solvent. The organic solvent is not particularly limited, but is preferably one in which both the reacting compound and the reactant compound are easily soluble. The organic solvent is not particularly limited, and examples thereof include toluene, mesitylene, chloroform (CHCl), alcohol, and THF (tetrahydrofuran). A catalyst may also be used, if necessary. The catalyst is not particularly limited, and examples thereof include DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), and triethylamine (TEA). The amounts of solvent and catalyst may be appropriately determined depending on the compound so that the reaction proceeds. The reaction temperature and time may also be appropriately determined depending on the compound so that the reaction proceeds. The reaction temperature may be, for example, 10 to 100°C, preferably 20 to 80°C, and the reaction time may be, for example, 1 to 200 hours, preferably 3 to 100 hours.

[0042] Regarding a synthesis example of a nitrile oxide compound having a nitrile oxide group and a cationic functional group, a synthesis example of a specific compound will be described. For example, a nitrile oxide compound having a nitrile oxide group and a cationic functional group, represented by compound P3, can be synthesized by the synthesis route shown in FIG. 1.

[0043] First, compound S (a compound having a hydroxyl group and an aldehyde group) is used as a starting material, and compound S is reacted with a compound into which a cationic group can be introduced (C5H4N-CH2-Cl (wherein C5H4N represents 2-pyridyl)) to obtain compound P1.

[0044] The aldehyde group in the prepared compound P1 is converted to 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 to -C≡N + -O - to synthesize compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic group).

[0045] Figure 2 shows the synthesis of compounds P1, P2, and P3 in the synthesis route of Figure 1.1 Figure 2 shows an example of a H-NMR (proton NMR) spectrum. Figure 3 shows an example of the results of thermogravimetric analysis (TGA) during the synthesis of compound P3 (a nitrile oxide compound (CNO-Py) having a nitrile oxide group and a cationic group). The spectra in Figure 2 and the TGA results in Figure 3 indicate that compounds P1, P2, and P3 were synthesized according to the synthetic route in Figure 1.

[0046] Furthermore, regarding a synthesis example of a nitrile oxide compound having a nitrile oxide group and an anionic functional group, a synthesis example of a specific compound will be described. For example, a nitrile oxide compound having a nitrile oxide group and an anionic functional group, represented by compound E, can be synthesized according to the synthesis route shown in FIG. 4.

[0047] First, compound A (a compound having a hydroxyl group and an aldehyde group) is used as the starting material, and compound A is reacted with a compound to which an anionic functional group can be introduced (Br-(CH2)5-C(=O)-O-CH2CH3) to obtain compound B. In the obtained compound B, -C(=O)-O-CH2CH3 (a group derived from a compound to which an anionic functional group can be introduced) is substituted with -C(=O)-OH (anionic functional group: carboxylic acid group) to obtain compound C.

[0048] The aldehyde group in the prepared compound C is converted to a group represented by -CH=N-OH to synthesize compound D. The group represented by -CH=N-OH in the obtained compound D is converted to -C≡N + -O - to synthesize compound E (a nitrile oxide compound having a nitrile oxide group and an anionic functional group).

[0049] Figure 5 shows the synthesis of compounds C, D, and E in the synthetic route of Figure 4. 1 Figure 5 shows an example of a H-NMR (proton NMR) spectrum. Figure 6 shows an example of the IR spectrum of compounds D and E in the synthesis route of Figure 4. The spectra in Figure 5 indicate that compounds C, D, and E have been synthesized, and the spectra in Figure 6 indicate that compounds D and E have been synthesized.

[0050] In the modified polymer obtained by reacting the nitrile oxide compound (polymer modifier) ​​having the nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing conjugated diene units and non-conjugated olefin units, the multicomponent copolymer A is not particularly limited as long as it is a polymer containing conjugated diene units and non-conjugated olefin units, and may contain other monomer units. Desirable examples of such other monomer units include aromatic vinyl units.

[0051] The multicomponent copolymer A may be a polymer that is solid at 25°C or a polymer that is liquid at 25°C.

[0052] In the multicomponent copolymer A, the conjugated diene unit is a structural unit derived from a conjugated diene compound, and examples of the conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, etc. These may be used alone or in combination of two or more, with 1,3-butadiene and isoprene being preferred, and 1,3-butadiene being more preferred.

[0053] In the multicomponent copolymer A, the non-conjugated olefin unit is a structural unit derived from a non-conjugated olefin, and examples of the non-conjugated olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, etc. These may be used alone or in combination of two or more, with ethylene, propylene, and 1-butene being preferred, and ethylene being more preferred.

[0054] In the multicomponent copolymer A, the aromatic vinyl unit optionally introduced is a constituent unit derived from an aromatic vinyl compound, and examples of the aromatic vinyl compound include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene, etc. These may be used alone or in combination of two or more, with styrene and α-methylstyrene being preferred, and styrene being more preferred.

[0055] The multicomponent copolymer A can be prepared, for example, by copolymerizing a conjugated diene compound, a non-conjugated olefin, and optionally an aromatic vinyl compound, or by copolymerizing a conjugated diene compound and optionally an aromatic vinyl compound, or a conjugated diene compound, a non-conjugated olefin, and optionally an aromatic vinyl compound, followed by hydrogenation to convert some of the conjugated diene units to non-conjugated olefin units. That is, the multicomponent copolymer A may be a copolymer of a conjugated diene compound, a non-conjugated olefin, and optionally an aromatic vinyl compound, or a polymer or copolymer of a conjugated diene compound and optionally an aromatic vinyl compound, or a hydrogenated product (hydrogenated copolymer) of a copolymer of a conjugated diene compound, a non-conjugated olefin, and optionally an aromatic vinyl compound. These may be used alone or in combination of two or more.

[0056] Among these, from the viewpoint of obtaining better effects, the multicomponent copolymer A is preferably a hydrogenated polymer or copolymer of a conjugated diene compound and, if necessary, an aromatic vinyl compound, and more preferably a hydrogenated styrene-butadiene copolymer (hydrogenated SBR).

[0057] The reason why the above-mentioned effect is more pronounced when the multicomponent copolymer A is a hydrogenated copolymer is not entirely clear, but it is thought that the hydrogenation causes crystallinity to develop and results in high breaking strength. In the case of hydrogenated styrene-butadiene copolymer (hydrogenated SBR), it is believed that the styrene units improve the rubber breaking strength and compression set. Therefore, it is believed that the overall performance of rubber breaking strength and compression set is significantly improved.

[0058] In order to obtain a better effect, the multicomponent copolymer A is preferably a polymer containing a conjugated diene unit, a non-conjugated olefin unit, and an aromatic vinyl unit. From the same viewpoint, the multicomponent copolymer A is preferably a copolymer containing ethylene units and conjugated diene units, or a copolymer containing ethylene units, conjugated diene units, and aromatic vinyl units, and more preferably a copolymer containing ethylene units and 1,3-butadiene, or a copolymer containing ethylene units, 1,3-butadiene units, and styrene units.

[0059] The reason why the above-mentioned effects are more effectively obtained when using polymers containing conjugated diene units, non-conjugated olefin units, and aromatic vinyl units is not entirely clear. However, it is thought that, for example, in the case of polymers containing conjugated diene units, non-conjugated olefin units, and aromatic vinyl units, the aromatic vinyl units improve the rubber breaking strength and compression set.

[0060] In preparing the multicomponent copolymer A, the polymerization method is not particularly limited, and may be random polymerization or block polymerization, with random polymerization being preferred.

[0061] When the multicomponent copolymer A is a hydrogenated copolymer, the hydrogenation method and reaction conditions are not particularly limited, and hydrogenation may be carried out by a known method and under known conditions. Typically, hydrogenation is carried out at 20 to 150°C under a hydrogen pressure of 0.1 to 10 MPa in the presence of a hydrogenation catalyst. Other production methods and conditions are also not particularly limited, and the contents described in WO 2016 / 039005, for example, can be applied.

[0062] When the multicomponent copolymer A is a hydrogenated copolymer, the hydrogenation rate is preferably 60 mol% or more, more preferably 80 mol% or more, even more preferably 88 mol% or more, even more preferably 90 mol% or more, particularly preferably 95 mol% or more, and is preferably 99 mol% or less, more preferably 98 mol% or less, based on 100 mol% of the total conjugated diene units before hydrogenation. Within the above ranges, the effect tends to be better obtained. On the other hand, from the viewpoint of strain recovery rate, the hydrogenation rate is preferably 95 mol % or less, more preferably 88 mol % or less, and even more preferably 60 mol % or less. The hydrogenation rate is 1 It can be calculated from the spectral reduction rate of the unsaturated bond portion of the spectrum obtained by measuring H-NMR.

[0063] Although the reason why the above-mentioned effects are more pronounced when the hydrogenation rate is high is not entirely clear, it is believed that a high hydrogenation rate increases crystallinity and results in high breaking strength, which is thought to significantly improve the overall performance of rubber breaking strength and compression set.

[0064] In the multicomponent copolymer A, the content of the conjugated diene units is preferably 2.0 mol% or more, more preferably 4.0 mol% or more, even more preferably 9.5 mol% or more, particularly preferably 32.0 mol% or more, and is preferably 50.0 mol% or less, more preferably 40.0 mol% or less, even more preferably 35.0 mol% or less, based on 100 mol% of all constituent units. Within the above ranges, the effect tends to be more favorable. On the other hand, from the viewpoint of the glass transition temperature, the content is preferably 32.0 mol % or less, more preferably 9.5 mol % or less, and even more preferably 4.0 mol % or less.

[0065] In the multicomponent copolymer A, the content of the non-conjugated olefin units is preferably 48 mol% or more, more preferably 70 mol% or more, and even more preferably 76 mol% or more, and is preferably 99 mol% or less, more preferably 98 mol% or less, and even more preferably 97 mol% or less, based on 100 mol% of all constituent units. Within the above ranges, the effect tends to be more favorable. On the other hand, from the viewpoint of strain recovery rate, the content is preferably 76 mol % or less, more preferably 70 mol % or less, and even more preferably 48 mol % or less.

[0066] In the multicomponent copolymer A, the content of aromatic vinyl units is preferably 5 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more, and is preferably 50 mol% or less, more preferably 45 mol% or less, and even more preferably 40 mol% or less, based on 100 mol% of all constituent units. Within the above ranges, the effect tends to be more favorable. On the other hand, from the viewpoint of strain recovery rate, the content is preferably 30 mol % or less, more preferably 20 mol % or less.

[0067] The multicomponent copolymer A may be an unmodified copolymer or a modified copolymer. Examples of the modified copolymer A include a terminally modified copolymer (a terminally modified copolymer having the functional group at the terminal) in which at least one terminal of the copolymer has been modified with a compound (modifying agent) having the functional group, a main-chain modified copolymer having the functional group in the main chain, a main-chain terminally modified copolymer having the functional group in the main chain and at least one terminal (for example, a main-chain terminally modified copolymer having the functional group in the main chain and at least one terminal modified with the modifier), and a terminally modified copolymer modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and into which a hydroxyl group or an epoxy group has been introduced.

[0068] Examples of the functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imido group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, and an epoxy group. These functional groups may have a substituent. Among these, an amino group (preferably an amino group in which a hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), and an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 6 carbon atoms) are preferred.

[0069] The weight average molecular weight (Mw) of the multicomponent copolymer A is preferably 100,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and particularly preferably 400,000 or more, and is preferably 2,000,000 or less, more preferably 1,500,000 or less, even more preferably 1,000,000 or less, and particularly preferably 600,000 or less. Within the above ranges, the effect tends to be more favorably obtained. The weight average molecular weight (Mw) can be determined by converting it into standard polystyrene based on the measured value obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation).

[0070] The method for reacting the nitrile oxide compound having the nitrile oxide group and the ionic functional group with the multicomponent copolymer A containing the conjugated diene unit and the non-conjugated olefin unit can be any method that allows the reaction to occur. For example, the nitrile oxide compound and the multicomponent copolymer A can be dissolved or energy can be applied as necessary to cause a cycloaddition reaction between the nitrile oxide group and the carbon-carbon double bond in the main chain of the multicomponent copolymer A, thereby allowing the reaction to form a five-membered ring to proceed.

[0071] The reaction process between the nitrile oxide compound and the multicomponent copolymer A is not particularly limited, and may be carried out in an organic solvent, in water, or without a solvent. The organic solvent is not particularly limited, but is preferably one in which both the nitrile oxide compound and the multicomponent copolymer A are easily soluble. Specific examples of the organic solvent include those mentioned above. The reaction temperature and time may be appropriately set depending on the nitrile oxide compound and the multicomponent copolymer A.

[0072] To explain a specific example of compound synthesis, for example, a reaction product (modified polymer) of the nitrile oxide compound and the multicomponent copolymer A can be synthesized according to the synthesis route shown in FIG.

[0073] FIG. 7 shows, as an example of a synthesis example of a reaction product (modified polymer) between the nitrile oxide compound and the multicomponent copolymer A, a synthesis route for synthesizing a reaction product (modified polymer) between the nitrile oxide compound having a nitrile oxide group and a cationic functional group and a nitrile oxide compound having a nitrile oxide group and an anionic functional group and the multicomponent copolymer A. Specifically, this shows a synthesis example in which a nitrile oxide compound having the nitrile oxide group and an anionic functional group (compound E) is first reacted with hydrogenated SBR, and then a nitrile oxide compound having the nitrile oxide group and a cationic functional group (compound P3) is further reacted to synthesize a reaction product (modified polymer) of compound P3 and compound E (nitrile oxide compound) with hydrogenated SBR (multicomponent copolymer A).

[0074] Specifically, the compound E (a nitrile oxide compound having a nitrile oxide group and an anionic functional group) and hydrogenated SBR are kneaded at 70°C for 15 minutes to obtain a modified polymer having an anionic functional group. Next, the resulting modified polymer having an anionic functional group and the above-mentioned compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic functional group) are kneaded at 70°C for 15 minutes to obtain the target reaction product (a reaction product (modified polymer) of the above-mentioned compound P3 and compound E (nitrile oxide compound) with hydrogenated SBR (multicomponent copolymer A)).

[0075] Figure 8 shows the polymers in the synthetic route of Figure 7. 1 Figure 8 shows an example of a H-NMR (proton NMR) spectrum. It shows that a nitrile oxide compound having a nitrile oxide group and an anionic functional group (compound E) and a nitrile oxide compound having a nitrile oxide group and a cationic functional group (compound P3) react with hydrogenated SBR to synthesize modified polymers having anionic and cationic functional groups.

[0076] The glass transition temperature (Tg) of the modified polymer is preferably above −50° C., more preferably at least −35° C., more preferably at least −20° C., and even more preferably at least −10° C., and the upper limit is preferably not more than 5° C., more preferably not more than 0° C., and even more preferably not more than −3° C. If it is within the above range, the effect tends to be better obtained. On the other hand, from the viewpoint of rubber for tires, the Tg is preferably −10° C. or lower, more preferably −20° C. or lower, and even more preferably −35° C. or lower. In this specification, the glass transition temperature (Tg) is a value measured in accordance with JIS-K7121:1987 using a differential scanning calorimeter at a temperature rise rate of 10°C / min.

[0077] <Rubber composition> (rubber component) As described above, the modified polymer may be either a polymer that is solid at 25° C. or a polymer that is liquid at 25° C., but a polymer that is solid at 25° C. is desirable, and in this case, it can be suitably used as a rubber component of a rubber composition. When the modified polymer is used as the rubber component, the overall performance of rubber rupture strength and compression set is improved.

[0078] The reason why the above-mentioned effects are more pronounced when the modified polymer is used as the rubber component is not entirely clear, but is presumed to be as follows. By introducing a nitrile oxide compound having a nitrile oxide group and an ionic functional group into a polymer, a network consisting of crosslinks by hydrogen bonds without sulfur crosslinking is formed. Furthermore, when this network is combined with a conventional sulfur-crosslinked rubber, it is believed that a rubber composition consisting of two networks will result. Because crosslinks due to hydrogen bonds are weaker than sulfur crosslinks, when strong energy is applied, the hydrogen bonds, which are more easily broken than sulfur crosslinks, undergo sacrificial fracture, dissipating the input energy and preventing the sulfur crosslinks from breaking, which is thought to improve the breaking strength of the rubber.In addition, because multiple ionic functional groups can aggregate to function as crosslinking points, it is thought that good permanent set can be imparted to polymers with a high content of non-conjugated olefin units. Therefore, it is presumed that the use of the modified polymer as the rubber component improves the overall performance of rubber breaking strength and compression set.

[0079] When the rubber composition uses the modified polymer as a rubber component, the modified polymer may be a composition obtained by mixing a modified polymer synthesized in advance by the above-mentioned production method or the like with other components, or may be a composition containing a modified polymer produced by reaction between the multicomponent copolymer A and the nitrile oxide compound having a nitrile oxide group and an ionic functional group, and, if necessary, other components, when the multicomponent copolymer A, the nitrile oxide compound having a nitrile oxide group and an ionic functional group, and, if necessary, other components are kneaded under the above-mentioned kneading conditions or the like to prepare a composition.

[0080] When the rubber composition uses the modified polymer as a rubber component, the rubber composition contains the modified polymer and, as necessary, rubber components such as other rubbers.

[0081] Here, the rubber component is generally a polymer with a weight-average molecular weight (Mw) of 10,000 or more, and is a rubber component that is not extracted with acetone. The rubber component is in a solid state at room temperature (25°C). The rubber component is a component that contributes to crosslinking.

[0082] When the rubber composition contains the modified polymer as a rubber component, the content of the modified polymer (content of the modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 20% by mass or more, even more preferably 50% by mass or more, and is preferably 90% by mass or less, more preferably 70% by mass or less, even more preferably 60% by mass or less. Within the above ranges, the effect tends to be more favorable. On the other hand, from the viewpoint of strain recovery rate, the content is preferably 5% by mass or more, more preferably 10% by mass or more, and is preferably 50% by mass or less, more preferably 20% by mass or less.

[0083] In addition, when one or more types of multicomponent copolymers A, one or more types of nitrile oxide compounds having a nitrile oxide group and an ionic functional group (cationic functional group, anionic functional group), and other components as necessary are kneaded under the above-mentioned kneading conditions, etc., and during kneading, each multicomponent copolymer A reacts with each nitrile oxide compound to produce two or more types of modified polymers, the content of each modified polymer is considered to include each modified polymer distributed proportionally according to the content ratio of the two or more types of multicomponent copolymers A. For example, if two types of multicomponent copolymer A (60 parts by mass of hydrogenated SBR, 40 parts by mass of hydrogenated BR), 5 parts by mass of a nitrile oxide compound having a nitrile oxide group and a cationic functional group, and 5 parts by mass of a nitrile oxide compound having a nitrile oxide group and an anionic functional group are kneaded together, and modified hydrogenated SBR and modified hydrogenated BR are generated during kneading, and a rubber composition containing these is produced, the proportion of the modified hydrogenated SBR is 66 parts by mass (=(60+40+5+5)×60 / (60+40)), and the proportion of the modified hydrogenated BR is 44 parts by mass (=(60+40+5+5)×40 / (60+40)).

[0084] From the viewpoint of obtaining better effects, the rubber composition preferably further contains a multicomponent copolymer B containing conjugated diene units and non-conjugated olefin units as a rubber component other than the modified polymer.

[0085] Although the reason why the above-mentioned effects are more pronounced when the multicomponent copolymer B is used is not entirely clear, it is believed that the use of the multicomponent copolymer B can prevent the sulfur crosslinks from being broken, thereby improving the rupture strength of the rubber, and therefore the overall performance of the rubber rupture strength and compression set is presumably improved.

[0086] Examples of the multicomponent copolymer B include the same as the multicomponent copolymer A. Among these, from the viewpoint of obtaining a better effect, the multicomponent copolymer B is preferably a hydrogenated polymer or copolymer of a conjugated diene compound and, if necessary, an aromatic vinyl compound, and more preferably a hydrogenated styrene-butadiene copolymer (hydrogenated SBR). Furthermore, from the viewpoint of obtaining a better effect, the multicomponent copolymer B is preferably a copolymer containing an ethylene unit and a conjugated diene unit, or a copolymer containing an ethylene unit, a conjugated diene unit, and an aromatic vinyl unit, and more preferably a copolymer containing an ethylene unit and a 1,3-butadiene, or a copolymer containing an ethylene unit, a 1,3-butadiene unit, and a styrene unit.

[0087] In the rubber composition, the content of the multicomponent copolymer B in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass or more, and is preferably 95% by mass or less, more preferably 90% by mass or less. Within the above ranges, the effect tends to be more favorably obtained. On the other hand, from the viewpoint of rubber breaking strength, the content is preferably 10% by mass or more, more preferably 20% by mass or more, and is preferably 80% by mass or less, more preferably 50% by mass or less.

[0088] The rubber composition may contain rubber components other than the modified polymer and the multicomponent copolymer B. Like the multicomponent copolymer A, such rubber components may be unmodified or modified rubber. Examples of functional groups introduced into the modified rubber include the same functional groups that can be introduced into the multicomponent copolymer A.

[0089] When the rubber composition contains other rubber components such as the multicomponent copolymer B in addition to the modified polymer, it is desirable that hydrogen bonds and sulfur crosslinks are formed in the rubber composition, which tends to produce better effects.

[0090] The reason why the above-mentioned effects are more pronounced when hydrogen bonds and sulfur crosslinks are formed in the rubber composition is not entirely clear, but is presumed to be as follows. By introducing a nitrile oxide compound having a nitrile oxide group and an ionic functional group into a polymer, a network consisting of crosslinks by hydrogen bonds without sulfur crosslinking is formed. Furthermore, when this network is combined with a conventional sulfur-crosslinked rubber, it is believed that a rubber composition consisting of two networks will result. Therefore, it is presumed that the overall performance of rubber breaking strength and compression set is improved, as in the above case.

[0091] Examples of other rubber components include diene rubbers. Examples of diene rubbers include isoprene rubbers, butadiene rubbers (BR), styrene butadiene rubbers (SBR), styrene isoprene butadiene rubbers (SIBR), ethylene propylene diene rubbers (EPDM), chloroprene rubbers (CR), and acrylonitrile butadiene rubbers (NBR). Examples of rubber components include butyl rubbers and fluororubbers. These may be used alone or in combination of two or more. These rubber components may be modified or hydrogenated, and extended rubbers extended with oils, resins, liquid rubber components, or the like may also be used. Among these, isoprene rubbers, BR, and SBR are preferred.

[0092] Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. NRs such as SIR20, RSS#3, and TSR20 are commonly used in the rubber industry. IRs are not particularly limited, and examples of IRs such as IR2200 are commonly used in the rubber industry. Modified NRs include deproteinized natural rubber (DPNR) and high-purity natural rubber. Modified NRs include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Modified IRs include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0093] The BR is not particularly limited, and examples thereof include high-cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, and BR synthesized using a rare earth catalyst (rare earth BR). These may be used alone or in combination of two or more. Of these, the BR preferably contains high-cis BR with a cis content of 90% by mass or more. The cis content is more preferably 95% by mass or more. The cis content can be measured by infrared absorption spectroscopy.

[0094] The cis content of BR means the cis content of the BR when there is one type of BR, and means the average cis content when there are multiple types of BR. The average cis content of BR can be calculated by {Σ(content of each BR × cis content of each BR)} / total content of all BRs. For example, when 100% by mass of the rubber component contains 20% by mass of BR with a cis content of 90% by mass and 10% by mass of BR with a cis content of 40% by mass, the average cis content of BR is 73.3% by mass (=(20×90+10×40) / (20+10)).

[0095] The BR may be either unmodified or modified. Examples of modified BR include modified BR into which the same functional group as that in the multicomponent copolymer A has been introduced. The BR may also be a hydrogenated butadiene polymer (hydrogenated BR).

[0096] As the BR, for example, products from Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Corporation, etc. can be used.

[0097] The SBR is not particularly limited, and examples thereof include emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc. These may be used alone or in combination of two or more.

[0098] The styrene content of the SBR is preferably 5% by mass or more, more preferably 20% by mass or more, and even more preferably 23.5% by mass or more. The styrene content is preferably 60% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. Within the above range, the effect tends to be more favorable. In this specification, the styrene content can be measured by pyrolysis gas chromatography analysis.

[0099] The styrene content of SBR means the styrene content of the SBR when there is one type of SBR, and means the average styrene content when there are multiple types of SBR. The average styrene amount of SBR can be calculated by {Σ(content of each SBR × styrene amount of each SBR)} / total content of all SBRs. For example, when 100% by mass of the rubber component contains 85% by mass of SBR with a styrene amount of 40% by mass and 5% by mass of SBR with a styrene amount of 25% by mass, the average styrene amount of the SBR is 39.2% by mass (=(85×40+5×25) / (85+5)).

[0100] The vinyl bond content of SBR is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. When the vinyl bond content is within the above range, that is, preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less, better effects tend to be obtained. In this specification, the vinyl bond amount (amount of 1,2-bonded butadiene units) can be measured by pyrolysis gas chromatography analysis.

[0101] The vinyl content of SBR (amount of 1,2-bonded butadiene units) is the proportion of vinyl bonds (unit: mass%) when the total mass of the butadiene parts in the SBR is taken as 100, and is calculated as vinyl content [mass%] + cis content [mass%] + trans content [mass%] = 100 [mass%]. When there is one type of SBR, it means the vinyl content of that SBR, and when there are multiple types, it means the average vinyl content. The average vinyl content of SBR can be calculated by Σ{content of each SBR × (100 [mass%] - styrene content of each SBR [mass%]) × vinyl content of each SBR [mass%]} / Σ{content of each SBR × (100 [mass%] - styrene content of each SBR [mass%])}. For example, in 100 parts by mass of the rubber component, 75 parts by mass of SBR with a styrene content of 40% by mass and a vinyl content of 30% by mass, 25 parts by mass of styrene and 10 parts by mass of vinyl are used. In the case where 15 parts by mass of SBR with a vinyl content of 20% by mass is used and the remaining 10 parts by mass are other than SBR, the average vinyl content of the SBR is 28% by mass (= {75 × (100 [% by mass] - 40 [% by mass]) × 30 [% by mass] + 15 × (100 [% by mass] - 25 [% by mass]) × 20 [% by mass])} / {75 × (100 [% by mass] - 40 [% by mass]) + 15 × (100 [% by mass] - 25 [% by mass])}.

[0102] Either unmodified or modified SBR can be used as SBR. Modified SBR includes modified SBR into which the same functional group as that in the multicomponent copolymer A has been introduced. Hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used as SBR.

[0103] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd., etc. can be used. SBR synthesized by a known method can also be used.

[0104] The raw materials (monomers) for synthetic rubbers such as IR, SBR, and BR may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires or non-rubber products such as polystyrene. Monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include recycled polyisoprene, recycled butadiene, and recycled aromatic vinyls. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyls include, but are not limited to, styrene. Among these, recycled polyisoprene (recycled isoprene), recycled butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) are preferably used as raw materials.

[0105] The method for producing the recycled monomer is not particularly limited, and examples thereof include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. The method for producing recycled naphtha is also not particularly limited, and examples thereof include decomposing rubber products such as tires under high temperature and pressure, decomposing with microwaves, or mechanically crushing and then extracting.

[0106] Furthermore, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to materials derived from natural resources such as plants. Examples of biomass include, but are not limited to, agricultural, forestry, and fishery products, sugar, wood chips, plant residues after useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0107] Monomers derived from biomass (biomass monomers) are not particularly limited and include biomass-derived butadiene and biomass-derived aromatic vinyl. Examples of butadienes include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyls include, but are not limited to, styrene. The method for producing biomass monomers is not particularly limited and includes, for example, biological and / or chemical and / or physical conversion of animals and plants. A representative example of biological conversion is fermentation by microorganisms, and examples of chemical and / or physical conversion include catalytic conversion, high heat conversion, high pressure conversion, electromagnetic wave conversion, critical fluid conversion, and combinations thereof.

[0108] The polymer synthesized from a biomass monomer component (biomass polymer) is not particularly limited, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymer synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyl. Examples of the aromatic vinyl / butadiene copolymer include styrene-butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0109] Whether the raw material for a polymer is derived from biomass can be determined by the pMC (percent modern carbon) measured in accordance with ASTM D6866-10.

[0110] pMC is the modern standard reference 14 of sample against C concentration 14 This is the ratio of C concentrations and is a value used as an index of the biomass ratio of a compound. The significance of this value is explained below.

[0111] 1 mole of carbon atoms (6.02 × 10 23 ) contains approximately 6.02 × 10 atoms, which is about one trillionth of the number of ordinary carbon atoms. 11 pieces 14C exists. 14 C is called a radioactive isotope, and its half-life is 5,730 years, and it decreases regularly. It takes 226,000 years for all of it to decay. Therefore, in fossil fuels such as coal, oil, and natural gas, which are thought to have been absorbed and fixed by plants and other organisms more than 226,000 years ago, C was also included in these when it was first fixed. 14 All C elements have decayed. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain 14 Therefore, chemicals produced from these fossil fuels do not contain any C element. 14 It does not contain any C elements.

[0112] on the other hand, 14 C is produced continuously by nuclear reactions in the atmosphere caused by cosmic rays, and this balances with the decrease due to radioactive decay. In the Earth's atmospheric environment, 14 Therefore, the amount of carbon derived from biomass resources currently circulating in the environment is constant. 14 As mentioned above, the C concentration is approximately 1 × 10 -12 The value is approximately mol %. Therefore, the biomass ratio of a certain compound can be calculated by using the difference between these values.

[0113] this 14 C is typically measured using accelerator mass spectrometry based on a tandem accelerator. 13 C concentration ( 13 C / 12 C). 14 C concentration ( 14 C / 12 C) is measured. 14 The modern standard reference for the C concentration is the carbon circulating in nature as of 1950. 14The specific standard substance used is the oxalic acid standard provided by NIST (National Institute of Standards and Technology). The specific activity of carbon in this oxalic acid (per gram of carbon) is 14 The radioactivity of C is separated into carbon isotopes, 13 The standard value is the value corrected for decay from 1950 to the measurement date. 14 This is used as the C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0114] Therefore, if rubber is made from 100% biomass-derived materials, although there are regional differences, under normal circumstances, it will usually not reach 100, and will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from petroleum and other fossil fuels, 14 When the carbon concentration is measured, it will show a value of about 0 pMC (for example, 0.3 pMC), which corresponds to the biomass ratio of 0% mentioned above.

[0115] From the above, it is preferable in terms of environmental protection to use a material such as rubber having a high pMC value, that is, a material such as rubber having a high biomass ratio, in a rubber composition.

[0116] (filler) The rubber composition preferably contains a filler. The filler is not particularly limited, and materials known in the rubber field can be used, including inorganic fillers such as carbon black, silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica, biochar, and poorly dispersible fillers. Of these, carbon black and silica are preferred from the viewpoint of obtaining better effects.

[0117] Carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. The raw material for carbon black may be a biomass material such as lignin or vegetable oil, or pyrolysis oil obtained by pyrolysis of waste tires. Carbon black may be produced by combustion, such as in a furnace process, by hydrothermal carbonization (HTC), or by pyrolysis of methane, such as in a thermal black process. Commercially available carbon black products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Columbia Carbon Co., Ltd. Carbon black may be used alone or in combination.

[0118] The nitrogen adsorption specific surface area (N2SA) of carbon black is 5m 2 / g or more is preferable, and 20m 2 / g or more is more preferable, and 40m 2 / g or more is more preferable. 2 / g or less is preferable, and 130m 2 / g or less is more preferable, and 120m 2 Within the above range, the effect tends to be better. The nitrogen adsorption specific surface area of ​​carbon black can be determined according to JIS K6217-2:2001.

[0119] The silica that can be used in the rubber composition is not particularly limited, and can be, for example, silica prepared by a dry process (anhydrous silica) or silica prepared by a wet process (hydrated silica), which are commonly used in the tire industry. The raw material for the silica is not particularly limited, and can be, for example, a mineral-derived raw material such as quartz, a biological raw material such as rice husk (for example, silica made from a biomass material such as rice husk), or silica recycled from a silica-containing product. Among these, hydrated silica prepared by a wet process is preferred because it contains a large number of silanol groups. These silicas can be used alone or in combination of two or more types.

[0120] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and then reacting the silicate with sulfuric acid in the same manner as conventional wet-process silica to produce a silicon dioxide precipitate, which is then filtered, washed with water, dried, and pulverized.

[0121] Silica recycled from silica-containing products can be, for example, silica recovered from products containing silica, such as electronic components such as semiconductors, tires, desiccants, and filtering materials such as diatomaceous earth. The recovery method is not particularly limited, and examples include thermal decomposition and decomposition by electromagnetic waves. Among these, silica recovered from electronic components such as semiconductors or tires is preferred.

[0122] When silica crystallizes, it becomes insoluble in water, and its component, silicic acid, cannot be utilized. By controlling the combustion temperature and duration, it is possible to suppress the crystallization of silica in rice husk ash (see, for example, JP 2009-2594 A and Akita Prefectural University Web Journal B / 2019, vol. 6, pp. 216-222).

[0123] Amorphous silica extracted from rice husks may be commercially available from Wilmar Co., Ltd., etc.

[0124] The nitrogen adsorption specific surface area (N2SA) of the silica is preferably 50 m2 / g or more, more preferably 80m 2 / g or more, more preferably 100m 2 The upper limit of the 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 Within the above range, there is a tendency for the effect to be better obtained. The N2SA of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0125] Examples of the hardly dispersible filler include microfibrillated plant fibers, short fiber cellulose, gel compounds, etc. Among these, microfibrillated plant fibers are preferred.

[0126] The microfibrillated plant fiber is preferably cellulose microfibrils, as they provide good reinforcing properties. The cellulose microfibrils are not particularly limited as long as they are derived from natural products, and examples include those derived from resource biomass such as fruits, grains, and root vegetables; wood, bamboo, hemp, jute, and kenaf; pulp, paper, and cloth obtained from these raw materials; waste biomass such as agricultural waste, food waste, and sewage sludge; unused biomass such as rice straw, wheat straw, and thinned wood; and cellulose produced by sea squirts, acetic acid bacteria, and the like. These microfibrillated plant fibers may be used alone or in combination of two or more.

[0127] In this specification, cellulose microfibrils typically refer to cellulose fibers having an average fiber diameter of 10 μm or less, more typically cellulose fibers having a microstructure formed by the aggregation of cellulose molecules and an average fiber diameter of 500 nm or less. Typical cellulose microfibrils are formed, for example, as an aggregate of cellulose fibers having the above-mentioned average fiber diameter.

[0128] In the rubber composition, the content of the filler (total amount of fillers such as carbon black and silica) is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more, per 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 even more preferably 100 parts by mass or less. Within the above ranges, better effects tend to be obtained. On the other hand, from the viewpoint of crosslinking by hydrogen bonding, the content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 30 parts by mass or less.

[0129] When the rubber composition contains carbon black, the amount of carbon black is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less. When the amount is within the above range, better effects tend to be obtained. On the other hand, from the viewpoint of crosslinking by hydrogen bonding, the content is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and is preferably 30 parts by mass or less, more preferably 5 parts by mass or less.

[0130] When the rubber composition contains silica, the content of silica is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less. When the content is within the above range, better effects tend to be obtained. On the other hand, from the viewpoint of crosslinking by hydrogen bonding, the content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and is preferably 35 parts by mass or less, more preferably 25 parts by mass or less.

[0131] (Silane coupling agent) When the rubber composition contains silica, it is preferable that the rubber composition further contains a silane coupling agent. The silane coupling agent is not particularly limited, and those known in the rubber field can be used, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N, Examples include sulfide-based compounds such as N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and NXT and NXT-Z manufactured by Momentive; vinyl-based compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products include those from Evonik, Momentive, Shin-Etsu Silicones Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Dow Corning Toray Co., Ltd. These may be used alone or in combination of two or more.

[0132] 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, even more 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, even more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less. Within the above range, the effect tends to be more favorably obtained.

[0133] (plasticizer) The rubber composition may contain a plasticizer. In this specification, the term "plasticizer" refers to a material that imparts plasticity to a rubber component, and includes both plasticizers that are liquid at 25°C and plasticizers that are solid at 25°C. Examples of plasticizers include resin components, oils, liquid polymers, and ester-based plasticizers. These plasticizers may be derived from mineral resources such as petroleum and natural gas, biomass-derived plasticizers, or naphtha recycled from rubber and non-rubber products. Low-molecular-weight hydrocarbon components obtained by pyrolysis and extraction of used tires or products containing various components may also be used as plasticizers. These plasticizers may be used alone or in combination.

[0134] Examples of plasticizers that can be used in the rubber composition include oils, liquid polymers, resins, etc. These may be used alone or in combination of two or more.

[0135] Examples of oils include mineral oil, vegetable oil, animal oil, etc. From the viewpoint of life cycle assessment, waste oils used in rubber mixers or engines, or refined waste cooking oils used in restaurants may also be used.

[0136] As used herein, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oil include paraffinic oil (mineral oil), naphthenic oil, and aromatic oil. Specific examples of mineral oil include mild extract solvated (MES), distillate aromatic extract (DAE), treated distillate aromatic extract (TDAE), treated residual aromatic extract (TRAE), and residual aromatic extract (RAE). Furthermore, as an environmental measure, oils with a low content of polycyclic aromatic compounds (PCA) can also be used. Examples of low PCA oils include MES, TDAE, and heavy naphthenic oil.

[0137] As used herein, examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and Japan wax. Further examples of vegetable oils include refined oils (such as salad oil) obtained by refining the above-mentioned oils, interesterified oils obtained by interesterifying the above-mentioned oils, hardened oils obtained by hydrogenating the above-mentioned oils, thermally polymerized oils obtained by thermally polymerizing the above-mentioned oils, oxidatively polymerized oils obtained by oxidizing the above-mentioned oils, and waste edible oils recovered from edible oils and the like. Vegetable oils may be liquid or solid at 25°C. These vegetable oils may be used alone or in combination of two or more.

[0138] The vegetable oil according to this embodiment preferably contains acylglycerol, and more preferably triacylglycerol. In this specification, acylglycerol refers to a compound in which a hydroxyl group of glycerin is ester-bonded to a fatty acid. The acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, the acylglycerol may be a monomer, a dimer, or a multimer (trimer or higher). Dimer or higher acylglycerols can be obtained by thermal polymerization, oxidative polymerization, or the like. Furthermore, the acylglycerol may be liquid or solid at 25°C.

[0139] The method for confirming whether the rubber composition contains the acylglycerol is not particularly limited, but may be any of the following: 1 For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at 25°C for 24 hours, and after removing the rubber composition, the 1 When H-NMR was measured, signals were observed around 5.26 ppm, 4.28 ppm, and 4.15 ppm when the signal of tetramethylsilane (TMS) was set at 0.00 ppm. These signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atoms of the ester group. In this paragraph, "around" refers to a range of ±0.10 ppm.

[0140] The fatty acid is not particularly limited and may be either an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0141] Among these, it is desirable that the fatty acid contains a fatty acid with few double bonds, i.e., a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As a vegetable oil containing such a fatty acid, for example, vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid may be used, or vegetable oil modified by ester exchange or the like may be used. Furthermore, in order to produce vegetable oil containing such a fatty acid, plants may be improved by breeding, genetic modification, genome editing, or the like.

[0142] As the oil, for example, oils commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0143] Examples of the liquid polymer include liquid diene polymers (liquid rubbers) and liquid farnesene polymers at 25°C. Examples of liquid rubber include liquid styrene butadiene copolymers (liquid SBRs), liquid butadiene polymers (liquid BRs), liquid isoprene polymers (liquid IRs), liquid styrene isoprene copolymers (liquid SIRs), liquid styrene butadiene styrene block copolymers (liquid SBS block polymers), and liquid styrene isoprene styrene block copolymers (liquid SIS block polymers). The terminals or main chains of these may be modified with polar groups. Hydrogenated versions of these compounds can also be used.

[0144] The liquid diene polymer has a weight average molecular weight (Mw) of 1.0×10 in terms of polystyrene as measured by gel permeation chromatography (GPC). 3 ~5.0×10 4 Preferably, it is 3.0 × 10 3 ~1.5×10 4 The lower or upper limit of Mw of the liquid diene polymer may be 4,500 or 8,500. In this specification, the Mw of the liquid diene polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0145] As the liquid diene polymer, for example, products available from Sartomer Co., Ltd., Kuraray Co., Ltd., etc. can be used.

[0146] The resin may be a resin commonly used in tire compounds, and may be liquid or solid at 25°C. Examples include aromatic vinyl polymers, coumarone-indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, and acrylic resins. The resin may also be a hydrogenated resin (hydrogenated resin). These may be used alone or in combination of two or more. The resin itself may also be a copolymer of monomer components derived from multiple sources. Among these, aromatic vinyl polymers, petroleum resins, terpene resins, and hydrogenated resins thereof are preferred.

[0147] When a resin that is solid at 25° C. is used, the softening point of the resin is preferably 50° C. or higher, more preferably 55° C. or higher, even more preferably 60° C. or higher, and particularly preferably 85° C. or higher. Also, the softening point is preferably 160° C. or lower, more preferably 150° C. or lower, even more preferably 140° C. or lower, and particularly preferably 100° C. or lower. Within the above range, better effects tend to be obtained. When the resin is liquid at 25°C, the softening point is preferably 20°C or lower, more preferably 10°C or lower, and even more preferably 0°C or lower. In the case of hydrogenated resins, it is desirable that the softening point is the same as above. The softening point of the resin is the temperature at which the ball drops when the softening point specified in JIS K6220-1:2001 is measured using a ring and ball softening point tester.

[0148] The aromatic vinyl polymer is a polymer containing an aromatic vinyl monomer as a constituent unit. For example, it may be a resin obtained by polymerizing α-methylstyrene and / or styrene, and specifically may be a homopolymer of styrene (styrene resin), a homopolymer of α-methylstyrene (α-methylstyrene resin), a copolymer of α-methylstyrene and styrene, or a copolymer of styrene and another monomer.

[0149] The coumarone-indene resin is a resin containing coumarone and indene as the main monomer components constituting the resin skeleton (main chain). Other monomer components contained in the skeleton besides coumarone and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, etc.

[0150] The coumarone resin is a resin containing coumarone as a main monomer component constituting the skeleton (main chain) of the resin.

[0151] The indene resin is a resin containing indene as a main monomer component constituting the skeleton (main chain) of the resin.

[0152] The phenolic resin may be a known polymer obtained by reacting phenol with an aldehyde such as formaldehyde, acetaldehyde, or furfural in the presence of an acid or alkali catalyst. Of these, those obtained by reacting with an acid catalyst (such as novolac phenolic resin) are preferred.

[0153] Examples of the rosin resin include rosin-based resins such as natural rosin, polymerized rosin, modified rosin, ester compounds thereof, and hydrogenated products thereof.

[0154] Examples of the petroleum resin include C5 resin, C9 resin, C5 / C9 resin, dicyclopentadiene (DCPD) resin, C9 / DCPD resin, and hydrogenated versions of these. Of these, DCPD resin, hydrogenated DCPD resin, C9 / DCPD resin, and C9 / hydrogenated DCPD resin are preferred.

[0155] The terpene resin is a polymer containing terpene as a structural unit. Examples include polyterpene resins obtained by polymerizing terpene compounds and aromatic-modified terpene resins obtained by polymerizing terpene compounds and aromatic compounds. Examples of aromatic-modified terpene resins include terpene phenol resins made from terpene compounds and phenolic compounds, terpene styrene resins made from terpene compounds and styrene compounds, and terpene phenol styrene resins made from terpene compounds, phenolic compounds, and styrene compounds. Examples of terpene compounds include α-pinene and β-pinene, phenolic compounds include phenol and bisphenol A, and aromatic compounds include styrene compounds (styrene, α-methylstyrene, etc.). Among these, aromatic-modified terpene resins are preferred.

[0156] The acrylic resin is a polymer containing an acrylic monomer as a constituent unit. For example, a styrene-acrylic resin having a carboxyl group and obtained by copolymerizing an aromatic vinyl monomer component with an acrylic monomer component can be used. Among them, a solvent-free carboxyl-containing styrene-acrylic resin can be preferably used.

[0157] Examples of the resins that can be used include products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, ExxonMobil, KRATON, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Co., Ltd.

[0158] From the viewpoint of sustainability, it is desirable to use the above-mentioned plant-derived plasticizers such as plant-derived oils and farnesene-based polymers as the plasticizer.

[0159] Farnesene polymers are polymers obtained by polymerizing farnesene and contain structural units based on farnesene. Farnesene has isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene), but (E)-β-farnesene, which has the following structure, is preferred. [ka]

[0160] The farnesene polymer may be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer). These may be used alone or in combination of two or more. Among these, a copolymer of farnesene and a vinyl monomer is preferred.

[0161] Examples of vinyl monomers include aromatic vinyl compounds such as styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, vinylxylene, vinylnaphthalene, vinyltoluene, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylene, as well as conjugated diene compounds such as butadiene and isoprene. These may be used alone or in combination of two or more. Among these, butadiene is preferred. That is, the farnesene-vinyl monomer copolymer is preferably a copolymer of farnesene and butadiene (farnesene-butadiene copolymer).

[0162] In the farnesene-vinyl monomer copolymer, the copolymerization ratio by mass of farnesene and vinyl monomer (farnesene / vinyl monomer) is preferably 40 / 60 to 90 / 10.

[0163] The farnesene polymer preferably has a weight average molecular weight (Mw) of 3,000 or more and 300,000 or less. The Mw of the farnesene polymer is preferably 8,000 or more, more preferably 10,000 or more, and is preferably 100,000 or less, more preferably 60,000 or less, and even more preferably 50,000 or less. Within the above ranges, the effects tend to be more favorably obtained.

[0164] The farnesene-based polymer may be either a liquid or solid at 25° C. Among these, a liquid farnesene-based polymer that is a liquid at 25° C. is preferred.

[0165] When the rubber composition contains a plasticizer, the content of the plasticizer (total amount of plasticizer) per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less. When the content is within the above range, better effects tend to be obtained. The plasticizer content includes the amount of oil and resin contained in the oil-extended rubber and resin-extended rubber.

[0166] When the rubber composition contains a solid plasticizer that is in a solid state at 25° C., the content of the solid resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, and is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less. Within the above ranges, the effect tends to be more favorably obtained. The content of the solid plasticizer also includes the amount of resin contained in the resin-extended rubber.

[0167] When the rubber composition contains a liquid plasticizer that is in a liquid state at 25° C., the content of the liquid plasticizer is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less. Within the above ranges, better effects tend to be obtained. The content of the liquid plasticizer includes the amount of oil contained in the oil-extended rubber and the amount of liquid resin in the resin-extended rubber extended with the liquid resin.

[0168] (Other ingredients) The rubber composition may further contain vulcanized rubber particles. The vulcanized rubber particles are particles made of vulcanized rubber, and specifically, rubber powder as specified in JIS K 6316:2017 can be used. From the standpoint of environmental considerations and cost, recycled rubber powder produced from crushed waste tires is preferred. These may be used alone or in combination of two or more types.

[0169] The vulcanized rubber particles are not particularly limited, and may be unmodified vulcanized rubber particles or modified vulcanized rubber particles.

[0170] As commercially available vulcanized rubber particles, for example, products from Lehigh Corporation, Muraoka Rubber Industries Co., Ltd., etc. can be used.

[0171] In the rubber composition, the content of the vulcanized rubber particles is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. Within the above ranges, better effects tend to be obtained.

[0172] The rubber composition preferably contains an antioxidant from the viewpoints of crack resistance, ozone resistance, and the like.

[0173] The antioxidant is not particularly limited, and examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), and N,N'-ditolyl-p-phenylenediamine. p-phenylenediamine antioxidants such as N-isopropyl-N'-phenyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymers; monophenol antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis-, tris-, and polyphenol antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products that can be used include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis, etc.

[0174] In the rubber composition, the content of the antioxidant is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, per 100 parts by mass of the rubber component, and is preferably 7.0 parts by mass or less, more preferably 5.0 parts by mass or less.

[0175] The rubber composition preferably contains stearic acid. In the rubber composition, the content of stearic acid is preferably 1.0 part by mass or more, more preferably 2.0 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of the rubber component.

[0176] As the stearic acid, conventionally known products can be used, for example, products available from NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., etc.

[0177] The rubber composition preferably contains zinc oxide. In the above rubber composition, the content of zinc oxide is preferably 1.0 part by mass or more, more preferably 2.0 parts by mass or more, and preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, per 100 parts by mass of the rubber component.

[0178] As the zinc oxide, conventionally known products can be used, for example, products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used. Alternatively, two or more of them may be used in combination.

[0179] The rubber composition may contain short fibers. The amount of the short fibers is preferably 1 part by mass or more, more preferably 5 parts by mass or more, based on 100 parts by mass of the rubber component, and is preferably 50 parts by mass or less, more preferably 30 parts by mass or less.

[0180] Examples of the short fibers include non-metallic inorganic short fibers such as glass fiber and carbon fiber, and non-metallic organic short fibers such as cellulose fiber, rayon fiber, acrylic fiber, polyester fiber, nylon fiber, aromatic polyamide fiber, urethane fiber, and aramid fiber.

[0181] The rubber composition may contain a processing aid. The content of the processing aid is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 6 parts by mass or less, based on 100 parts by mass of the rubber component.

[0182] The rubber composition preferably contains sulfur. In the rubber composition, the sulfur content is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.7 parts by mass or more, and is preferably 3.5 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.5 parts by mass or less, per 100 parts by mass of the rubber component. Within the above ranges, the effect tends to be more favorably obtained. On the other hand, from the viewpoint of strain recovery rate, the content is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, and preferably 1.0 part by mass or less, more preferably 0.7 part by mass or less.

[0183] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. Commercially available products include those from Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. These may be used alone or in combination of two or more.

[0184] The rubber composition preferably contains a vulcanization accelerator. In the rubber composition, the content of the vulcanization accelerator is not particularly limited and may be freely determined according to the desired vulcanization rate and crosslink density, but is preferably 0.5 parts by mass or more, more preferably 1.3 parts by mass or more, and even more preferably 1.5 parts by mass or more, per 100 parts by mass of the rubber component. The upper limit is preferably 8.0 parts by mass or less, more preferably 6.0 parts by mass or less, and even more preferably 4.0 parts by mass or less.

[0185] The type of vulcanization accelerator is not particularly limited, and commonly used ones 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-benzothiazyl 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, Nt-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-orthotolylguanidine, and orthotolylbiguanidine. Commercially available products include those from Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., etc. 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.

[0186] In addition to the above components, the rubber composition may also contain compounding agents generally used in the tire industry, such as a mold release agent, as appropriate.

[0187] In this specification, various materials containing carbon atoms (e.g., rubber, oil, resin, vulcanization accelerator, antioxidant, surfactant, etc.) may be derived from atmospheric carbon dioxide. The compound may be obtained from carbon dioxide by directly converting carbon dioxide or by converting methane obtained through a methanation process in which methane is synthesized from carbon dioxide.

[0188] The rubber composition can be produced, for example, by kneading the above components using a rubber kneading device such as an open roll or a Banbury mixer, followed by vulcanization.

[0189] Regarding kneading conditions, in the base kneading step in which additives other than the crosslinking agent (vulcanizing agent) and vulcanization accelerator are kneaded, the kneading temperature is preferably 100°C or higher, more preferably 120°C or higher, and preferably 180°C or lower, more preferably 170°C or lower. In the finish kneading step in which the vulcanizing agent and vulcanization accelerator are kneaded, the kneading temperature is preferably 80°C or higher, and preferably 120°C or lower, more preferably 110°C or lower. Furthermore, the composition kneaded with the vulcanizing agent and vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is preferably 140°C or higher, more preferably 150°C or higher, and preferably 190°C or lower, more preferably 185°C or lower.

[0190] The rubber composition can be suitably applied to tire components. The tire component is not particularly limited, and examples thereof include any tire component such as a tread (cap tread, base tread, etc.), a sidewall, a bead apex, a clinch apex, an inner liner, an undertread, a breaker topping, a bright topping, etc. Among these, tire surface layer components that are susceptible to external damage, such as a sidewall, a tread, a wing, and a clinch, are preferred, and a sidewall is more preferred, in view of their good overall performance in terms of rubber fracture strength and compression set.

[0191] <Tires> The rubber composition can be suitably used for tires.

[0192] The tire is not particularly limited, and examples thereof include pneumatic tires, solid tires, airless tires, etc. Among these, pneumatic tires are preferred.

[0193] The above-mentioned tires can be suitably used as summer tires, winter tires (studless tires, snow tires, studded tires, etc.), all-season tires, etc. The above-mentioned tires can also be used as tires for passenger cars, large passenger cars, large SUVs, heavy-duty tires for trucks, buses, etc., light trucks, motorcycles, racing tires (high-performance tires), aircraft tires, mining tires, etc. Among these, the tires can be suitably used as tires for passenger cars and light trucks.

[0194] The tire is manufactured by a conventional method using the rubber composition. For example, a rubber composition containing various materials is extruded in an unvulcanized state to match the shape of a tire component, and molded together with other tire components in a tire building machine by a conventional method to form an unvulcanized tire, which is then heated and pressurized in a vulcanizer to manufacture the tire. [Example]

[0195] Below, examples (embodiments) that are considered preferable for implementation will be shown, but the scope of the present invention is not limited to the examples.

[0196] The modified hydrogenated styrene-butadiene copolymer was produced and evaluated by the following method. The physical properties are shown in Table 1.

[0197] <Polymer evaluation method> (Bound styrene content (styrene content)) Using a polymer as a sample, 100 mg of the sample is dissolved in chloroform to make a total volume of 100 mL, and the resultant solution is used as a measurement sample. The amount of bound styrene (mass %) relative to 100 mass % of the sample polymer is measured based on the amount of absorption of ultraviolet light by the phenyl group of styrene (near 254 nm) (measuring device: Shimadzu UV-2450 spectrophotometer).

[0198] (Polymer hydrogenation rate) Using a polymer as a sample, 1 The hydrogenation rate of the polymer is measured by H-NMR measurement. 1 The conditions for H-NMR measurement are as follows: <Measurement conditions> Measuring equipment: JNM-LA400 (JEOL) Solvent: deuterated chloroform Measurement sample: rubbery polymer Sample concentration: 50mg / mL Observation frequency: 400MHz Chemical shift standard: TMS (tetramethylsilane) Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45° Measurement temperature: 26℃

[0199] (Amount of nitrile oxide compound having nitrile oxide group and cationic functional group added) The amount of the nitrile oxide compound (CNO-Py) having a nitrile oxide group and a cationic functional group reacted with the polymer is measured as follows. The ratio (mol%) of nitrile oxide compound added to carbon-carbon double bonds in the polymer was measured by IR. 1 H-NMR measurement and 13 Calculated by C-NMR measurement.

[0200] (Amount of nitrile oxide compound having nitrile oxide group and anionic functional group added) The amount of the nitrile oxide compound (CNO-COOH) having a nitrile oxide group and an anionic functional group reacted with the polymer is measured as follows. The ratio (mol%) of nitrile oxide compound added to carbon-carbon double bonds in the polymer was measured by IR. 1 H-NMR measurement and 13 Calculated by C-NMR measurement.

[0201] (glass transition temperature (Tg)) The glass transition temperature is measured in accordance with JIS-K7121:1987 using a differential scanning calorimeter (Q200) manufactured by TA Instruments Japan Co., Ltd. at a heating rate of 10°C / min.

[0202] <Production of hydrogenated styrene butadiene copolymer (hydrogenated SBR)> n-Hexane, styrene, 1,3-butadiene, TMEDA (N,N,N',N'-tetramethylethylenediamine), and n-butyllithium were added to a heat-resistant reactor that had been thoroughly purged with nitrogen. The mixture was then stirred at 50°C for 5 hours to carry out the polymerization reaction. Hydrogen gas was then supplied at 0.4 MPa-gauge pressure while stirring for 20 minutes, allowing the unreacted lithium at the polymer terminals to react and produce lithium hydride. The hydrogen gas supply pressure was set to 0.7 MPa-gauge, the reaction temperature to 90°C, and hydrogenation was carried out using a titanocene dichloride-based catalyst. When the cumulative amount of hydrogen absorption reached the target hydrogenation rate, the reaction temperature was returned to room temperature, the hydrogen pressure was returned to normal, and the reactor was withdrawn. The reaction solution was then stirred and poured into water, and the solvent was removed by steam stripping to obtain the hydrogenated copolymers (1) to (3) (hydrogenated styrene-butadiene copolymers) shown in Table 1.

[0203] <Synthesis of nitrile oxide compounds bearing nitrile oxide groups and cationic functional groups (CNO-Py)> Compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic functional group) is synthesized according to the synthetic route shown in FIG.

[0204] (Compound S→Compound P1) A stir bar is added to a three-neck flask, and 2-hydroxy-1-naphthaldehyde (compound S) and DMF (N,N-dimethylformamide) are added and stirred to dissolve. K2CO3 is added to the flask and stirred for 1 hour. 2-(Chloromethyl)pyridine Hydrochloride is added to the mixture and stirred to dissolve. The solution is heated in an oil bath and reacted at 100°C. After 3 hours, the solution is cooled to room temperature, diluted with ethyl acetate, and poured into a separatory funnel. The organic layer is collected, dried with MgSO4, and the solvent is removed using an evaporator. The resulting crude product is recrystallized from ethanol to obtain compound P1.

[0205] (Compound P1 → Compound P2) Add a stir bar to a beaker, add compound P1 and ethanol, and stir to dissolve. Add an aqueous solution of CH3COONa·3H2O and NH2OH·HCl to P1 and react at room temperature for 4 hours. Then, add a large amount of water to the reaction mixture to precipitate compound P2. Collect the precipitate and dry it to obtain compound P2.

[0206] (Compound P2 → Compound P3) Compound P2 is dispersed in 2-propanol, and an aqueous solution of NaClO is added to the compound P2 solution using a dropping funnel at 0-5°C to allow the reaction to proceed. After the addition is complete, the reaction is allowed to proceed for 1 hour, and then a large amount of water is added to the solution to precipitate compound P3. The precipitate is collected and dried to obtain compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic functional group, CNO-Py).

[0207] synthetic 1 The H-NMR spectrum (FIG. 2) and TGA (FIG. 3) show that compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic functional group) has been synthesized.

[0208] <Synthesis of nitrile oxide compounds with nitrile oxide groups and anionic functional groups (CNO-COOH)> Compound E (a nitrile oxide compound having a nitrile oxide group and an anionic functional group) is synthesized according to the synthetic route shown in FIG.

[0209] (Compound A → Compound B) First, add a stir bar, 2-hydroxy-1-naphthaldehyde (compound A), K2CO3, DMF (N,N-dimethylformamide), and ethyl 6-bromohexanoate to a three-neck flask and stir to dissolve. Then, heat in an oil bath and react at 100°C for 3 hours. Cool to room temperature and separate using ethyl acetate and water. Dry the ethyl acetate layer with MgSO4, evaporate, and recrystallize the residue with hexane to obtain compound B.

[0210] (Compound B → Compound C) Compound B and NaOH are dissolved in a mixture of THF: iPrOH: HO (4:2:1) and reacted overnight at room temperature. After the reaction is complete, the mixture is neutralized with hydrochloric acid and evaporated. The residue is diluted with water and poured into a separatory funnel with ethyl acetate to separate the layers. The ethyl acetate layer is dried over MgSO, evaporated to dryness, and then vacuum dried to obtain compound C.

[0211] (Compound C → Compound D) Add a stir bar, compound C, and ethanol to a 500 ml beaker and stir to dissolve. Add an aqueous solution of CH3COONa·3H2O and NH2OH·HCl to the compound C solution and allow to react at room temperature for 4 hours to obtain a precipitate. Filter the mixture, collect the precipitate, and dry it in vacuo to obtain compound D.

[0212] (Compound D → Compound E) A stirrer, compound D, and 2-propanol are added to a three-neck flask, which is then placed in an ice bath and stirred to disperse. NaClO solution is added to the flask using a dropping funnel at 0-5°C, and the reaction is allowed to proceed. After the reaction is complete, the pH is adjusted to approximately 5 with HCl, and the mixture is separated with CHCl3. The CHCl3 layer is dried over MgSO4, evaporated to dryness, and then recrystallized from ethanol / water to obtain the desired compound E (a nitrile oxide compound having a nitrile oxide group and an anionic functional group).

[0213] synthetic 1 The H-NMR spectrum (FIG. 5) and IR spectrum (FIG. 6) show that compound E (a nitrile oxide compound having a nitrile oxide group and an anionic functional group) has been synthesized.

[0214] <Synthesis of modified polymer (modified hydrogenated styrene butadiene copolymer)> The hydrogenated copolymers (1) to (3) (hydrogenated styrene-butadiene copolymer) obtained above are used to obtain modified polymers (modified hydrogenated copolymers (4) to (6)). Specifically, according to Table 1, the compound E (CNO-COOH) is added to the hydrogenated copolymer (1), (2), or (3), and the mixture is kneaded at 70°C for 15 minutes to allow the reaction to proceed during the kneading. Next, the compound P3 (CNO-Py) is added to the resulting mixture, and the mixture is kneaded at 70°C for 15 minutes to allow the reaction to proceed during the kneading, thereby obtaining modified polymers (modified hydrogenated copolymers (4) to (6)) that have been modified with both the CNO-COOH and CNO-Py compounds.

[0215] [Table 1]

[0216] Copolymer (7) in Table 1 is the following material. Copolymer (7): ESBR1502 (manufactured by ENEOS Materials Corporation, E-SBR, styrene content: 24% by mass, vinyl content: 17% by mass, non-oil-extended product containing no oil per 100 parts by mass of rubber solids)

[0217] <Preparation of Rubber Composition> The various chemicals used will be explained below. Hydrogenated copolymers (1) to (3): the above hydrogenated styrene butadiene copolymers (hydrogenated SBR) Modified hydrogenated copolymers (4) to (6): the above modified polymers (modified hydrogenated styrene butadiene copolymers) Copolymer (7): ESBR1502 Carbon black: Show Black N220 (N2SA: 111m) manufactured by Cabot Japan Co., Ltd. 2 / g) Silica: Evonik Ultrasil VN3 (N2SA: 175 ml 2 / g) Silane coupling agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Resin: Exxon Mobil Oppa PR-395 (hydrogenated DCPD resin) Oil: H&R VIVATEC 500 (aromatic process oil) Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Anti-aging agent: Nocrac 6C manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: NOF Corporation Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccela D manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccela CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0218] (Production of rubber composition) According to the formulation shown in Table 2, chemicals other than sulfur and vulcanization accelerator are kneaded for 5 minutes at 130°C using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded mixture. Sulfur and a vulcanization accelerator are added to the kneaded mixture, which is then kneaded at 70°C for 4 minutes to obtain an unvulcanized rubber composition. The unvulcanized rubber composition is press-vulcanized at 170° C. for 12 minutes to obtain a vulcanized rubber composition.

[0219] The vulcanized rubber composition was measured and evaluated for physical properties as follows. The results are shown in Table 2. The reference comparative examples are as follows. Table 1: Comparative Example 1

[0220] <Rubber breaking strength> A No. 7 dumbbell test piece is prepared, and a tensile test is carried out using an A&D tensile testing machine (RTG-1210) at a test temperature of 23°C and a tensile test speed of 200 mm / min, and the following TB and EB are measured. TB: The strength at break TB (MPa) per cross-sectional area of ​​the narrowest part of the test piece (the dumbbell-shaped constricted part located in the center). EB: The test piece is set on the testing machine with a chuck distance of 20 mm and a tensile test is carried out. The chuck distance at break is measured and the value calculated using the following formula is the elongation at break, EB (%). Distance between chucks at break (mm) / initial distance between chucks (20 mm) x 100 Furthermore, the fracture energy is calculated from the obtained TB and EB as follows, and is expressed as an index with the value of the reference comparative example being 100. Breaking energy = TB x EB / 2 The greater the breaking energy, the better the rubber breaking strength (durability).

[0221] <Strain recovery rate> The compression set (%) of the rubber composition is measured in accordance with JIS K6262:2013, and the strain recovery rate (%) is calculated as 100 minus the compression set (%). The results are expressed as an index, with the calculated value for Reference Comparative Example 1 being 100. A larger index indicates a larger strain recovery rate, i.e., a smaller compression set.

[0222] <Overall performance> The overall performance of rubber breaking strength and compression set is evaluated by the sum of the two indices obtained by evaluating the rubber breaking strength and the strain recovery rate. The larger the value, the better the overall performance.

[0223] [Table 2]

[0224] In Table 2, "CNO amount" represents the content of monomer units added by the CNO compound in 100 parts by mass of the rubber component. For example, the CNO amount in Example 1 is 20 parts by mass of modified hydrogenated copolymer (4) (modified hydrogenated SBR) × 5 / 100 (amount of butadiene units) = 1.0 mol%.

[0225] The "double bond content" in Table 2 represents the content of monomer units having double bonds in 100 parts by mass of the rubber component. For example, the double bond content in Example 1 is 80 parts by mass of hydrogenated copolymer (1) (hydrogenated SBR) × 5 / 100 (amount of butadiene units) = 4.0 mol % (the modified hydrogenated copolymer to which a CNO compound is added is assumed to be 100 mol % added, and the calculation is based on the assumption that no double bonds remain).

[0226] The present invention (1) is a modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit.

[0227] The present invention (2) is the modified polymer according to the present invention (1), wherein the multicomponent copolymer A is a polymer containing a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit.

[0228] The present invention (3) is the modified polymer according to the present invention (1) or (2), in which the multicomponent copolymer A is a hydrogenated copolymer.

[0229] The present invention (4) is the modified polymer according to the present invention (3), wherein the hydrogenated copolymer has a hydrogenation rate of 80 mol % or more.

[0230] The present invention (5) is a modified polymer in any combination with any of the present inventions (1) to (4), in which the multicomponent copolymer A is a hydrogenated styrene-butadiene copolymer.

[0231] The present invention (6) is a modified polymer in any combination with any of the present inventions (1) to (5), wherein the nitrile oxide compound contains a nitrile oxide compound having a nitrile oxide group and a cationic functional group, and a nitrile oxide compound having a nitrile oxide group and an anionic functional group.

[0232] The present invention (7) is a rubber composition containing a modified polymer in any combination with any of the present inventions (1) to (6).

[0233] The present invention (8) is the rubber composition according to the present invention (7), which further comprises a multicomponent copolymer B containing conjugated diene units and non-conjugated olefin units.

[0234] The present invention (9) is the rubber composition according to the present invention (7) or (8), in which hydrogen bonds and sulfur crosslinks are formed.

[0235] The present invention (10) is a tire using a rubber composition in any combination with any of the present inventions (7) to (9).

Claims

1. A modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an ionic functional group with a multicomponent copolymer A containing a conjugated diene unit and a non-conjugated olefin unit.

2. 2. The modified polymer according to claim 1, wherein the multicomponent copolymer A is a polymer containing a conjugated diene unit, a non-conjugated olefin unit, and an aromatic vinyl unit.

3. 3. The modified polymer according to claim 1, wherein the multicomponent copolymer A is a hydrogenated copolymer.

4. 4. The modified polymer according to claim 3, wherein the hydrogenated copolymer has a hydrogenation rate of 80 mol % or more.

5. 3. The modified polymer according to claim 1, wherein the multicomponent copolymer A is a hydrogenated styrene-butadiene copolymer.

6. 3. The modified polymer according to claim 1, wherein the nitrile oxide compound comprises a nitrile oxide compound having a nitrile oxide group and a cationic functional group, and a nitrile oxide compound having a nitrile oxide group and an anionic functional group.

7. A rubber composition comprising the modified polymer according to claim 1 or 2.

8. The rubber composition according to claim 7, further comprising a multicomponent copolymer B containing conjugated diene units and non-conjugated olefin units.

9. The rubber composition according to claim 7, wherein hydrogen bonds and sulfur crosslinks are formed.

10. A tire using the rubber composition according to claim 7.

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