Polymer modifier, rubber composition and tire

Abstract

To provide a polymer modifier having a high reaction rate with a polymer and capable of controlling a cationic group amount in the polymer, a modified polymer introducing the polymer modifier and a rubber composition and a tire using the modified polymer.SOLUTION: A polymer modifier has a nitrile oxide group and a cationic group.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Rubbers having ionic molecules have been disclosed as polymers with various properties. For example, it has been proposed to introduce a unit containing carboxylic acid into styrene-butadiene rubber. However, these generally have problems such as a low reactivity with the polymer, difficulty in controlling the amount of carboxylic acid groups in the polymer, and gelation. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention has an object to solve the above-mentioned problems and to provide a polymer modifier that has a high reactivity with a polymer and is capable of controlling the amount of cationic groups in the polymer, a modified polymer incorporating the polymer modifier, and a rubber composition and a tire using the modified polymer. [Means for solving the problem]

[0004] The present invention relates to a polymer modifying agent having a nitrile oxide group and a cationic group. Effect of the Invention

[0005] According to the present invention, since the polymer modifier has a nitrile oxide group and a cationic group, the reaction rate with the polymer is high and the amount of the cationic group in the polymer can be controlled. [Brief description of the drawings]

[0006] [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 group. [Diagram 2]FIG. 2 is an example of 1H-NMR (proton NMR) spectra of compounds P1, P2, and P3 in the total pathway of FIG. 1. [Diagram 3] 1 is an example of the results of thermogravimetric analysis during the synthesis of compound P3. [Figure 4] This is an example of synthesis showing that a nitrile oxide compound having a nitrile oxide group and a cationic group reacts with a polymer having a double bond to synthesize a polymer having a cationic group. [Diagram 5] FIG. 5 is an example of a 1H-NMR (proton NMR) spectrum of a polymer in the total path of FIG. [Figure 6] 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 group. [Figure 7] FIG. 1 is a diagram showing the relationship between strain and stress. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] <Polymer Modifier> The present invention is a polymer modifier having a nitrile oxide group and a cationic group (nitrile oxide compound). The polymer modifier has a high reactivity with a polymer, and can control the amount of cationic groups in the polymer. In addition, the polymer modifier can provide a modified polymer having a cationic group introduced therein, and a rubber composition and a tire using the modified polymer.

[0008] The applicant has proposed a technique in WO2022 / 244317 to synthesize a nitrile oxide compound having a carboxylic acid group and add styrene butadiene rubber or butadiene rubber in a solution. In this case, the reaction rate of the nitrile oxide compound having a carboxylic acid group can be controlled to about 60%, and the addition rate of the double bond can be controlled to about 0.1 to 10%, but there are problems such as a high amount of solution used in the solution reaction, being unfriendly to the environment, and being difficult to scale up, and it is desirable to further increase the reaction rate.

[0009] In the present invention, when a nitrile oxide compound having a cationic group such as a pyridine group is synthesized and the nitrile oxide compound is added to a polymer such as styrene butadiene rubber or butadiene rubber, a high reaction rate can be obtained in the reaction between the nitrile oxide compound and the polymer even in the absence of a solvent. For example, when a rubber and a nitrile oxide compound having a pyridine group are kneaded in a mixer at a temperature of 70° C. for about 15 minutes to react, a high reaction rate of about 90% or more can be obtained as the reaction rate of the nitrile oxide compound having pyridine. In addition, the reaction rate of the nitrile oxide compound having a carboxylic acid group alone when kneaded with a polymer is, for example, less than 30%, but when the nitrile oxide compound having a carboxylic acid group is kneaded with a polymer together with a nitrile oxide compound having a pyridine group, not only a high reaction rate can be obtained between the nitrile oxide compound having a pyridine group and the polymer, but also the reaction rate between the nitrile oxide compound having a carboxylic acid group and the polymer can be improved, for example, the reaction rate can be improved to 70% or more. As described above, by using a nitrile oxide compound having a cationic group as a modifying agent for a polymer, the reaction rate with the polymer is improved, and it is also possible to control the addition rate of double bonds (double bond modification rate). Furthermore, by using a nitrile oxide compound having an anionic group such as a carboxylic acid group together with a nitrile oxide compound having a cationic group as a modifying agent, the reaction rate between the nitrile oxide compound having an anionic group and the polymer can also be improved.

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

[0011] [ka]

[0012] In the nitrile oxide compound having the nitrile oxide group and the cationic group, the cationic group is preferably introduced at the end of the nitrile oxide compound. The nitrile oxide compound may be a compound having one cationic group or a compound having two or more cationic groups. The cationic group in the nitrile oxide compound may be one type or two or more types.

[0013] The cationic group includes monovalent cationic groups such as amino, ammonium, and imino groups, and 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 given as an example of the cationic group is not limited to -NH2, and also includes substituted amino groups and cyclic amino groups. Examples of the substituted amino group include monoalkylamino groups, dialkylamino groups, monoarylamino groups, diarylamino groups, 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 them, from the viewpoint of obtaining a greater effect, cyclic amino group is preferred, and pyridine group and substituted pyridine group are more preferred.

[0014] Exemplary optionally substituted pyridine groups include the following: 2-pyridyl, 3-pyridyl, 4-pyridyl: [ka] and the following -CH3 substituted 3-pyridines: [ka] etc.

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

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

[0017] The monovalent hydrocarbon group in X (monovalent hydrocarbon group containing a cationic group) means a monovalent hydrocarbon group that constitutes the skeleton of X and in which a cationic group has been substituted with a hydrogen atom. For example, when X is a group represented by -(CH2)5-C5H4N (pyridine group: cationic group), the monovalent hydrocarbon group in X is -(CH2)5-H.

[0018] The monovalent hydrocarbon group in X may be a substituted or unsubstituted monovalent hydrocarbon group, which may be linear, branched, or cyclic, but is preferably cyclic. The monovalent hydrocarbon group in X may contain a heteroatom. The substituent is not particularly limited, and may be a known group such as a hydroxyl group or a halogen group (-Cl, -Br, etc.). The heteroatom is not particularly limited, and may be oxygen, nitrogen, etc. These substituents and heteroatoms may be present in one or more.

[0019] The monovalent hydrocarbon group for X preferably has 3 or more, more preferably 6 or more, and preferably 30 or less, more preferably 20 or less, and even more preferably 16 or less.

[0020] Examples of the monovalent hydrocarbon group in 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 in 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).

[0021] In the monovalent hydrocarbon group of X, examples of substituted or unsubstituted linear alkyl groups and branched alkyl groups which may contain heteroatoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, 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 which 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 which 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. Examples of the monovalent hydrocarbon group in 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).

[0022] 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 and a substituted or unsubstituted aryl group which may contain a heteroatom are bonded together.

[0023] The compound having the nitrile oxide group and the cationic group is preferably a compound containing 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 them, a compound having a benzene ring or a naphthalene ring is preferred, and a compound having a naphthalene ring is more preferred.

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

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

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

[0027] Y (a substituted or unsubstituted divalent hydrocarbon group which may contain a heteroatom) may be linear, branched, or cyclic. Examples of the heteroatom and substituent in Y include the heteroatoms and substituents described above. Y may have one or more of these substituents and heteroatoms.

[0028] The divalent hydrocarbon group for Y preferably has 1 or more carbon atoms, and preferably has 20 or less, more preferably 10 or less, and further preferably 6 or less.

[0029] Examples of Y (a substituted or unsubstituted divalent hydrocarbon group which may contain a 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.

[0030] 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.

[0031] The compound having a naphthalene ring represented by the above formula is an example of a suitable example, and the -C≡N + -O -The substitution sites of the group represented by -YA are not particularly limited and may be any of the 1st to 8th positions. + -O - , preferably substituted with -YA.

[0032] Next, a method for synthesizing the nitrile oxide compound having the nitrile oxide group and the cationic group will be described. An example of a method for synthesizing the nitrile oxide compound having the nitrile oxide group and the cationic group will be described below, but the nitrile oxide compound is not limited to the one obtained by such a synthesis method, and includes a compound obtained by any synthesis method that can be synthesized.

[0033] First, a compound having a hydroxyl group and an aldehyde group is used as a starting material, and the compound having the hydroxyl group and the aldehyde group is reacted with a compound into which a cationic group can be introduced. If necessary, a group derived from the compound into which a cationic group can be introduced in the obtained material is substituted with the cationic group.

[0034] 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 following formula (1), a nitrile oxide compound having a nitrile oxide group and a cationic group can be synthesized.

[0035] 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 compound to be reacted and the compound to be reacted are easily dissolved. The organic solvent is not particularly limited, and examples thereof include toluene, mesitylene, chloroform (CHCl3), alcohol, and THF (tetrahydrofuran). A catalyst may be used as necessary. The catalyst is not particularly limited, and examples thereof include DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), and triethylamine (TEA). The amount of solvent and the amount of catalyst may be appropriately set according to the compound so that the reaction proceeds. The reaction temperature and time may also be appropriately set according to 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.

[0036] To explain a specific example of the synthesis of a compound, for example, a nitrile oxide compound having a nitrile oxide group and a cationic group, represented by compound P3, can be synthesized according to the synthesis route shown in FIG.

[0037] 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 to which a cationic group can be introduced (C5H4N-CH2-Cl (wherein C5H4N represents 2-pyridyl)) to obtain compound P1.

[0038] 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).

[0039] Figure 2 shows the total pathway of compounds P1, P2, and P3 in Figure 1. 1FIG. 2 shows an example of a H-NMR (proton NMR) spectrum. FIG. 3 shows an example of a thermogravimetric analysis (TGA) result during the synthesis of compound P3 (a nitrile oxide compound (CNO-Py) having a nitrile oxide group and a cationic group). The spectra in FIG. 2 and the TGA result in FIG. 3 show that compounds P1, P2, and P3 are synthesized through the combined route in FIG. 1.

[0040] <Modified polymer> The modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer is a modified polymer obtained by reacting the nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer (such as a polymer having an unsaturated bond). By using the modified polymer, mechanical properties, wet grip performance, etc. are improved.

[0041] The mechanism by which the above-mentioned effects are obtained is not clear, but is presumed to be as follows. The nitrile oxide compound having the nitrile oxide group and the cationic group can react with various unsaturated polymers, so that the nitrile oxide compound can be easily added to an unsaturated polymer such as a diene rubber, and a polymer having an ionic bond (a site where an ionic bond is formed) can be easily synthesized, and the content of the ionic bond in the polymer can be easily adjusted. The ionic bonded polymer has ionic clusters in the polymer, and the mechanical performance is improved. In addition, for example, when the diene rubber having the nitrile oxide compound introduced therein is applied to a rubber composition for tires, when the rubber composition comes into contact with a wet road surface, the ionic bond dissociates, the crosslinking is loosened, and the elastic modulus is reduced. Therefore, when driving on a wet road surface, the contact area with the road surface increases, friction increases, and loss is improved, so that it is presumed that the wet grip performance is improved.

[0042] The method of reacting the nitrile oxide compound having the nitrile oxide group and the cationic group with the polymer can be any method capable of reacting. For example, the nitrile oxide compound and the polymer having an unsaturated bond 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 polymer, and the reaction to generate a five-membered ring can be promoted.

[0043] The polymer may, for example, be a polymer having a carbon-carbon double bond. Examples of the polymer having a carbon-carbon double bond include rubber components such as diene rubber. Examples of diene rubber include isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). Other examples include butyl rubber and fluororubber. Among these, from the viewpoint of tire performance such as wet grip performance, SBR, BR, and isoprene rubber are preferred, and SBR and BR are more preferred.

[0044] The diene rubber may be a non-modified diene rubber or a modified diene rubber. The modified diene rubber may be any diene rubber having a functional group that interacts with a filler such as silica. Examples of the modified diene rubber include terminal-modified diene rubber (terminal-modified diene rubber having the functional group at the terminal) in which at least one terminal of the diene rubber has been modified with a compound (modifier) ​​having the functional group, main-chain modified diene rubber having the functional group in the main chain, main-chain terminal-modified diene rubber having the functional group in the main chain and at least one terminal (for example, main-chain terminal-modified diene rubber having the functional group in the main chain and at least one terminal modified with the modifier), and terminal-modified diene rubber modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or epoxy group introduced therein.

[0045] 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 imide 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 them, an amino group (preferably an amino group in which a hydrogen atom of an 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.

[0046] There are no particular limitations on the SBR, and examples of the SBR that can be used 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 kinds.

[0047] The styrene content of SBR is preferably 5% by mass or more, more preferably 20% by mass or more, and even more preferably 24% 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 better obtained. In this specification, the styrene content is 1 It can be measured by H-NMR measurement.

[0048] The styrene amount of SBR means the styrene amount of the SBR when there is one type of SBR, and means the average styrene amount 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)).

[0049] The vinyl bond content of SBR is preferably 3% by mass or more, more preferably 10% by mass or more, and even more preferably 17% by mass or more. When the vinyl bond content is within the above range of preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, the effect tends to be better. In this specification, the vinyl bond amount (1,2-bonded butadiene unit amount) can be measured by infrared absorption spectroscopy.

[0050] The vinyl content of SBR (amount of 1,2-bonded butadiene units) is the proportion of vinyl bonds when the total mass of the butadiene parts in SBR is taken as 100 (unit: mass%), 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, there are 75 parts by mass of SBR with a styrene content of 40 mass% and a vinyl content of 30 mass%, 25 parts by mass of styrene, and 10 parts by mass of vinyl. In the case where SBR with a vinyl content of 20 mass% is 15 parts by mass and the remaining 10 parts by mass is a component other than SBR, the average vinyl content of the SBR is 28 mass% (={75 × (100 [mass%] - 40 [mass%]) × 30 [mass%] + 15 × (100 [mass%] - 25 [mass%]) × 20 [mass%])} / {75 × (100 [mass%] - 40 [mass%]) + 15 × (100 [mass%] - 25 [mass%])}.

[0051] Both unmodified and modified SBR can be used. Modified SBR includes modified SBR with the same functional groups as modified rubber. Hydrogenated styrene-butadiene copolymer (hydrogenated SBR) can also be used as SBR.

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

[0053] The BR is not particularly limited, and for example, high cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, BR synthesized using a rare earth catalyst (rare earth BR), etc. can be used. These may be used alone or in combination of two or more. In particular, 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.

[0054] The cis amount of BR means the cis amount of the BR when there is one type of BR, and means the average cis amount 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)).

[0055] In addition, either unmodified or modified BR can be used as the BR. Modified BR includes modified BR in which the same functional group as that of modified rubber is introduced. In addition, hydrogenated butadiene polymer (hydrogenated BR) can also be used as the BR.

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

[0057] Examples of isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. Examples of NR include SIR20, RSS♯3, TSR20, and other rubber industry-standard rubbers. Examples of IR include IR2200 and other rubber industry-standard rubbers. Examples of modified NR include deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), and other rubbers. Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0058] The reaction process between the nitrile oxide compound and the polymer such as the diene rubber 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 polymer are easily dissolved. Specific examples of the organic solvent include those mentioned above. The reaction temperature and time may be appropriately set according to the nitrile oxide compound and the polymer at which the reaction proceeds.

[0059] In particular, even without a solvent, the reaction between the polymer and the nitrile oxide compound can be progressed by kneading the polymer with the nitrile oxide compound, and it is also possible to obtain a modified polymer in which the nitrile oxide compound having the nitrile oxide group and the cationic group reacts with the polymer during kneading. In the kneading process, the reaction temperature (kneading temperature) and reaction temperature (kneading time) may be appropriately set to the temperature and time at which the reaction proceeds, and the reaction temperature (kneading temperature) is preferably 10 to 100°C, more preferably 50 to 80°C, and the reaction time (kneading time) is preferably 1 minute to 200 hours, more preferably 3 minutes to 100 hours, and even more preferably 5 minutes to 1 hour.

[0060] To explain a specific example of the synthesis of a compound, for example, a reaction product (modified polymer) of the above-mentioned nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer having a double bond can be synthesized by the synthesis route shown in FIG.

[0061] For example, the nitrile oxide compound having the nitrile oxide group and the cationic group (compound P3) is kneaded with BR and SBR (diene rubber) at 70° C. for 15 minutes to obtain the target reaction product (modified polymer having the cationic group). In addition, a high reaction rate of compound P3 is also obtained.

[0062] Figure 5 shows the synthesis of the polymer in the synthesis route of Figure 4. 1 This is an example of a H-NMR (proton NMR) spectrum. (A) is that of BR. 1 H-NMR spectrum, (B) of SBR 1 H-NMR spectrum, (C) is BR with a pyridine group (cationic group). 1 H-NMR spectrum, (D) is SBR with pyridine group (cationic group) 1 5(C) and (D) are examples of H-NMR spectra. They show that a nitrile oxide compound having a nitrile oxide group and a cationic group (compound P3 above) reacts with BR and SBR to synthesize a polymer having a cationic group.

[0063] <Rubber composition> The rubber composition contains, as a rubber component, the modified polymer (hereinafter also referred to as "modified polymer (A)") obtained by reacting the nitrile oxide compound having the nitrile oxide group and the cationic group with the polymer. By using the modified polymer, mechanical properties, wet grip performance, etc. are improved.

[0064] Conventionally, when preparing a rubber composition using ionic bonds, there is a limit to the type of ion-modified rubber. For example, when SBR is used, there is a limit to the SBR skeleton. However, when the above-mentioned nitrile oxide compound is used, it is possible to impart a cationic group regardless of the skeleton structure, which is considered to facilitate adjustments such as further improving mechanical properties and wet grip performance.

[0065] The rubber composition contains the modified polymer (A), and may be a composition in which the modified polymer (A) previously synthesized by the above-mentioned production method or the like is mixed with other components, or may be a composition containing the modified polymer (A) produced by reacting the polymer and the nitrile oxide compound during kneading the above-mentioned polymer such as the diene rubber, the nitrile oxide compound having a nitrile oxide group and a cationic group, and, if necessary, other components, under the above-mentioned kneading conditions to produce a composition.

[0066] From the viewpoint of obtaining a better effect, it is desirable that the rubber composition further contains, as the rubber component, a modified polymer (B) obtained by reacting a nitrile oxide compound having a nitrile oxide group and an anionic group with a polymer, in addition to the modified polymer (A).

[0067] Examples of the anionic 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 iodine group. Examples of the acidic functional group include a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a sulfuric acid group, a phosphonic acid group, a phosphoric acid group, a phosphinic acid group, a maleic acid group, an acid anhydride group (maleic anhydride group, etc.), a fumaric acid group, an itaconic acid group, an acrylic acid group, a methacrylic acid group, and a mercapto group. Among these, a carboxylic acid group (carboxyl group) is preferred.

[0068] Examples of the nitrile oxide compound having a nitrile oxide group and an anionic group include compounds in which the cationic group of the nitrile oxide compound having a nitrile oxide group and a cationic group is replaced with an anionic group.

[0069] The synthesis of the nitrile oxide compound having the nitrile oxide group and the anionic group is, for example, first performed by reacting a compound having a hydroxyl group and an aldehyde group as a starting material with a compound into which an anionic group can be introduced. If necessary, a group derived from the compound into which an anionic group can be introduced in the obtained material is substituted with the anionic group. 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 - A nitrile oxide compound having a nitrile oxide group and an anionic group can be synthesized by converting the nitrile oxide group to a group represented by the formula: Specifically, the nitrile oxide compound having the nitrile oxide group and an anionic group can be synthesized by the method described in WO2022 / 244317.

[0070] In the modified polymer (B), the method of reacting the nitrile oxide compound having the nitrile oxide group and the anionic group with the polymer can be any method capable of reacting. For example, the nitrile oxide compound and the polymer having an unsaturated bond can be dissolved or energy can be applied as necessary to cause a cyclization addition reaction between the nitrile oxide group and the carbon-carbon double bond in the main chain of the polymer, and the reaction to generate a five-membered ring can be advanced. Specifically, the modified polymer (B) can be synthesized by reacting the nitrile oxide compound having the nitrile oxide group and the anionic group with the polymer by the method described in WO2022 / 244317. The modified polymer (B) can also be synthesized by kneading the polymer and the nitrile oxide compound under the above-mentioned solvent-free conditions.

[0071] The rubber composition contains a rubber component such as the modified polymer (A) and, if necessary, the modified polymer (B). Here, the rubber component is generally a polymer having a weight average molecular weight (Mw) of 10,000 or more, and is a rubber component that is not extracted with acetone. The rubber component is in a solid state at room temperature (25°C). When the rubber component is a rubber component, the rubber component is a component that contributes to crosslinking.

[0072] In the rubber composition, examples of the rubber component include the modified polymers (A) and (B) as well as the polymers such as the diene rubber.

[0073] The weight average molecular weight of the rubber component is preferably 50,000 or more, more preferably 150,000 or more, even more preferably 200,000 or more, and particularly preferably 270,000 or more, and is preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,000,000 or less. Within the above ranges, the effect tends to be better obtained.

[0074] In this specification, the weight average molecular weight (Mw) can be determined by converting it into standard polystyrene based on the measured value by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation). In the case of a polymer having a modifying group, the modifying group interacts with the silica gel of the column, making it impossible to obtain an accurate Mw, so that the Mw is measured before carrying out the modification treatment.

[0075] In the rubber composition, the content of the modified polymer (A) (modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and may be 100% by mass or less, or may be 90% by mass or less, 85% by mass or less, or 80% by mass or less. When it is within the above range, the effect tends to be better obtained. The content of the modified polymer (A) means the content of the modified polymer (A) in the case of a composition obtained by mixing the modified polymer (A) synthesized by reacting a nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer in advance by the above-mentioned production method or the like with other components, and also means the total amount of the polymer and the nitrile oxide compound in the case of kneading a polymer, a nitrile oxide compound having a nitrile oxide group and a cationic group, and other components as necessary, under the above-mentioned kneading conditions or the like, and reacting the polymer with the nitrile oxide compound during kneading to produce the modified polymer (A).

[0076] In the rubber composition, the content of the modified polymer (B) (modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an anionic group with a polymer) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and may be 100% by mass or less, or may be 90% by mass or less, 85% by mass or less, or 80% by mass or less. When it is within the above range, the effect tends to be better obtained. In addition, the content of the modified polymer (B) means the content of the modified polymer (B) in the case of a composition obtained by mixing a modified polymer (B) synthesized by reacting a nitrile oxide compound having a nitrile oxide group and an anionic group with a polymer in advance by the above-mentioned production method or the like with other components, and also means the total amount of the polymer and the nitrile oxide compound in the case of kneading a polymer, a nitrile oxide compound having a nitrile oxide group and an anionic group, and, if necessary, other components, under the above-mentioned kneading conditions or the like, and generating the modified polymer (B) by reacting the polymer with the nitrile oxide compound during kneading.

[0077] When the rubber composition contains modified SBR (A) obtained by reacting SBR with a nitrile oxide compound having a nitrile oxide group and a cationic group, the content of the modified SBR (A) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. Within the above ranges, the effect tends to be better obtained.

[0078] When the rubber composition contains the modified BR (A) obtained by reacting the nitrile oxide compound having the nitrile oxide group and the cationic group with the BR, the content of the modified BR (A) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less. Within the above ranges, the effect tends to be better obtained.

[0079] When the rubber composition contains the modified isoprene rubber (A) obtained by reacting the nitrile oxide compound having the nitrile oxide group and the cationic group with the isoprene rubber, the content of the modified isoprene rubber (A) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less. Within the above ranges, the effect tends to be better obtained.

[0080] When the rubber composition contains modified SBR (B) obtained by reacting SBR with a nitrile oxide compound having a nitrile oxide group and an anionic group, the content of the modified SBR (B) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. Within the above ranges, the effect tends to be better obtained.

[0081] When the rubber composition contains the modified BR (B) obtained by reacting the nitrile oxide compound having a nitrile oxide group and an anionic group with BR, the content of the modified BR (B) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. Within the above ranges, the effect tends to be better obtained.

[0082] When the rubber composition contains the modified isoprene rubber (B) obtained by reacting the nitrile oxide compound having the nitrile oxide group and the anionic group with the isoprene rubber, the content of the modified isoprene rubber (B) in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less. Within the above ranges, the effect tends to be better obtained.

[0083] In addition, when one or more kinds of polymers, one or more kinds of nitrile oxide compounds having a nitrile oxide group and an ionic group (cationic group or anionic group), and other components as necessary are kneaded under the above kneading conditions, etc., and two or more kinds of modified polymers are generated by reaction between each polymer and each nitrile oxide compound during kneading, the content of each modified polymer includes each modified polymer proportionally distributed according to the content ratio of the two or more kinds of polymers and the content ratio of the two or more kinds of nitrile oxide compounds having a nitrile oxide group and an ionic group (cationic group or anionic group). For example, in the case where two types of polymers (60 parts by mass of BR, 40 parts by mass of isoprene-based rubber) and 10 parts by mass of one type of nitrile oxide compound having a nitrile oxide group and a cationic group (polymer modifier) ​​are kneaded, modified BR and modified isoprene-based rubber are generated during kneading, and a rubber composition containing these is manufactured, the ratio of the nitrile oxide compound having a nitrile oxide group and a cationic group modified BR is 6 parts by mass (=10×60 / (60+40)), the content of the modified BR is 66 parts by mass (=60+6), the ratio of the nitrile oxide compound having a nitrile oxide group and a cationic group modified isoprene-based rubber is 4 parts by mass (=10×40 / (60+40)), and the content of the modified isoprene-based rubber is 44 parts by mass (=40+4).

[0084] The rubber composition desirably contains a filler. The filler is not particularly limited, and materials known in the rubber field can be used, for example, inorganic fillers such as carbon black, silica, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, mica, biochar, poorly dispersible fillers, etc. Among them, carbon black and silica are preferred from the viewpoint of obtaining a greater effect.

[0085] In the rubber composition, the content of the filler (total amount of fillers such as carbon black and silica) is preferably 2 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 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, the effect tends to be better obtained. In this specification, the above-mentioned nitrile oxide group and nitrile oxide compounds having a cationic group are not included in the packing material.

[0086] Carbon black is not particularly limited, but examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Co., Ltd., Shin-Nichika Carbon Co., Ltd., Columbia Carbon Co., Ltd., and the like. These may be used alone or in combination of two or more. In addition to conventional carbon black made from mineral oils and the like, carbon black made from biomass materials such as lignin may also be used. Furthermore, regenerated carbon black (recycled carbon black) may also be used.

[0087] The nitrogen adsorption specific surface area (N2SA) of carbon black is 5m 2 / g or more is preferable, and 50m 2 / g or more is more preferable, and 90m 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, there is a tendency that the effect is better obtained. The nitrogen adsorption specific surface area of ​​carbon black is determined in accordance with JIS K6217-2:2001.

[0088] In the rubber composition, the content 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. Within the above ranges, the effect tends to be better obtained.

[0089] In the rubber composition, examples of silica that can be used include dry process silica (anhydrous silica) and wet process silica (hydrated silica). Among them, wet process silica is preferred because it has a large number of silanol groups. Commercially available products include those from Degussa, Rhodia, Tosoh Silica, Solvay Japan, and Tokuyama. These may be used alone or in combination of two or more.

[0090] As the silica, plant-derived silica can also be suitably used. Examples of plant-derived silica include silica derived from plants containing silica. Examples of plants containing silica include rice, corn, sugarcane, horsetail, wheat, barley, rye, pearl barley, millet, foxtail millet, Japanese barnyard millet, and Erianthus. In addition, the saccharification residue of the above-mentioned plants containing silica can also be used. Among them, rice husks and straws with high silica content are preferred, and rice husks are more preferred. In addition, the plant containing silica may be one that has been burned to ash or one that has been carbonized.

[0091] In the rubber composition, the content of silica is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, and is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less, based on 100 parts by mass of the rubber component. When the content is within the above range, the effect tends to be better obtained.

[0092] The nitrogen adsorption specific surface area (N2SA) of the silica is preferably 50 m 2 / g or more, more preferably 100m2 / g or more, more preferably 150m 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.

[0093] Examples of the poorly dispersible filler include microfibrillated vegetable fibers, short fiber cellulose, gel compounds, etc. Among these, microfibrillated vegetable fibers are preferred.

[0094] The microfibrillated plant fiber is preferably cellulose microfibril, since it has good reinforcing properties. The cellulose microfibril is not particularly limited as long as it is derived from a natural product, and examples thereof include those derived from resource biomass such as fruits, grains, and root vegetables, wood, bamboo, hemp, jute, and kenaf, and pulp, paper, cloth, agricultural waste, waste biomass such as food waste and sewage sludge obtained from these as raw materials, unused biomass such as rice straw, wheat straw, and thinned wood, as well as cellulose produced by sea squirts, acetic acid bacteria, etc. These microfibrillated plant fibers may be used alone or in combination of two or more.

[0095] 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.

[0096] When the rubber composition contains a poorly dispersible filler, the content of the poorly dispersible filler is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit of the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 10 parts by mass or less. Within the above range, the effect tends to be better obtained.

[0097] 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, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N, Examples of such silylsilanes include sulfide-based silylsilanes such as N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based silylsilanes such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z; vinyl-based silylsilanes such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based silylsilanes such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based silylsilanes such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silylsilanes such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based silylsilanes such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products include those manufactured by Degussa, Momentive, Shin-Etsu Silicones, Tokyo Chemical Industry, Azumax, and Dow Corning Toray Co., Ltd. These may be used alone or in combination of two or more.

[0098] 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, based on 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 better obtained.

[0099] The rubber composition may contain a plasticizer. In this specification, the plasticizer is a material that imparts plasticity to the rubber component, and may be liquid or solid at room temperature (25° C.) These may be used alone or in combination of two or more kinds. In this specification, the above-mentioned nitrile oxide group and nitrile oxide compounds having a cationic group are not included in the plasticizer.

[0100] The plasticizer may be an oil, a liquid polymer, a resin, etc. These may be used alone or in combination of two or more kinds.

[0101] The oil is not particularly limited, and may be any conventionally known oil, such as paraffinic process oil, aromatic process oil, naphthenic process oil, low PCA (polycyclic aromatic) process oil such as TDAE and MES, vegetable-derived oil, and mixtures thereof. These may be used alone or in combination of two or more. From the viewpoint of life cycle analysis, lubricating oil or waste edible oil after use in a rubber mixing mixer or automobile engine may be used as appropriate.

[0102] Examples of the plant-derived oils (also called vegetable oils) include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil.

[0103] As the above oil, for example, products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., Ltd., H&R Co., Ltd., Toyokuni Oil Mills Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kosan Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0104] Examples of the liquid polymer include liquid diene polymers (liquid rubber) and liquid farnesene polymers at 25°C. Examples of liquid rubber include liquid styrene butadiene copolymers (liquid SBR), liquid butadiene polymers (liquid BR), liquid isoprene polymers (liquid IR), liquid styrene isoprene copolymers (liquid SIR), liquid styrene butadiene styrene block copolymers (liquid SBS block polymers), and liquid styrene isoprene styrene block copolymers (liquid SIS block polymers). The ends or main chains of these may be modified with polar groups. Hydrogenated products of these may also be used.

[0105] The liquid diene polymer has a weight average molecular weight (Mw) of 1.0×10 in terms of polystyrene 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-based polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0106] As the liquid diene polymer, for example, products available from Sartomer Co., Ltd., Kuraray Co., Ltd., etc. can be used.

[0107] The resin may be a resin that is commonly used as a tire compound, and may be liquid or solid at room temperature (25°C). Examples of the resin 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 of multiple origins. Among these, aromatic vinyl polymers, petroleum resins, terpene resins, and hydrogenated resins thereof are preferable.

[0108] When a resin that is solid at room temperature is used, the softening point of the resin is preferably 50° C. or higher, more preferably 55° C. or higher, 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, the effect tends to be better obtained. When the resin is liquid at room temperature, the softening point is preferably 20° C. or lower, more preferably 10° C. or lower, and even more preferably 0° C. or lower. In the case of hydrogenated resins, it is desirable for the softening point to be similar to that mentioned 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.

[0109] The aromatic vinyl polymer is a polymer containing an aromatic vinyl monomer as a structural unit. For example, it can be a resin obtained by polymerizing α-methylstyrene and / or styrene, and specifically, it can be a homopolymer of styrene (styrene resin), a homopolymer of α-methylstyrene (α-methylstyrene resin), a copolymer of α-methylstyrene and styrene, a copolymer of styrene and another monomer, etc.

[0110] The coumarone-indene resin is a resin containing coumarone and indene as 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.

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

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

[0113] 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. Among these, those obtained by reacting with an acid catalyst (such as novolac-type phenolic resin) are preferred.

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

[0115] Examples of the petroleum resin include C5 resin, C9 resin, C5 / C9 resin, dicyclopentadiene (DCPD) resin, C9 / DCPD resin, and hydrogenated versions of these resins. Among these, DCPD resin, hydrogenated DCPD resin, C9 / DCPD resin, and C9 / hydrogenated DCPD resin are preferred.

[0116] The terpene resin is a polymer containing terpene as a constituent unit. For example, polyterpene resin obtained by polymerizing a terpene compound, aromatic modified terpene resin obtained by polymerizing a terpene compound and an aromatic compound, etc. can be mentioned. As the aromatic modified terpene resin, terpene phenol resin made from terpene compounds and phenolic compounds, terpene styrene resin made from terpene compounds and styrene compounds, and terpene phenol styrene resin made from terpene compounds, phenolic compounds, and styrene compounds can also be used. In addition, examples of the terpene compound include α-pinene, β-pinene, etc., examples of the phenolic compound include phenol, bisphenol A, etc., and examples of the aromatic compound include styrene compounds (styrene, α-methylstyrene, etc.). Among them, aromatic modified terpene resin is preferable.

[0117] 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 and an acrylic monomer component, such as a styrene-acrylic resin, can be used. Among them, a solventless carboxyl group-containing styrene-acrylic resin can be preferably used.

[0118] 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, Exxon Mobil Corporation, KRATON, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Co., Ltd.

[0119] From the viewpoint of sustainability, it is desirable to use, as the plasticizer, a plant-derived plasticizer such as the plant-derived oil or farnesene-based polymer.

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

[0121] The farnesene-based 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 them, a copolymer of farnesene and a vinyl monomer is preferred.

[0122] 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-t-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethylether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-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).

[0123] 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.

[0124] The farnesene-based polymer preferably has a weight average molecular weight (Mw) of 3000 or more and 300,000 or less. The Mw of the farnesene-based polymer is preferably 8000 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 effect tends to be more preferably obtained.

[0125] The farnesene-based polymer may be either a liquid or solid polymer at room temperature (25° C.), and is preferably a liquid farnesene-based polymer that is a liquid at room temperature (25° C.).

[0126] When the rubber composition contains a plasticizer, the content of the plasticizer (total amount of the plasticizer) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. Within the above range, the effect tends to be better obtained. The plasticizer content includes the amount of oil and resin contained in the oil-extended rubber and resin-extended rubber.

[0127] In the rubber composition, the content of the solid plasticizer in a solid state at room temperature (25°C) is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 7 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less. Within the above range, the effect tends to be better obtained. The content of the resin in a solid state at room temperature (25° C.) is also desirably in the same range.

[0128] In the rubber composition, the content of the liquid plasticizer in a liquid state at room temperature (25°C) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. Within the above range, the effect tends to be better obtained. The liquid plasticizer content includes the amount of oil contained in the oil-extended rubber and the amount of liquid resin in the resin-extended rubber that has been extended with the liquid resin. A similar range is also desirable for the oil content that is liquid at room temperature (25°C).

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

[0130] The antiaging agent is not particularly limited, and examples thereof include naphthylamine-based antiaging agents such as phenyl-α-naphthylamine; diphenylamine-based antiaging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, Examples of the antioxidant include p-phenylenediamine antioxidants such as amines; quinoline antioxidants such as polymerized 2,2,4-trimethyl-1,2-dihydroquinoline; 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 antioxidants and quinoline antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymerized 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd.

[0131] In the rubber composition, the content of the antioxidant is preferably 0.2 parts by mass or more, more preferably 2.0 parts by mass or more, and even more preferably 3.4 parts by mass or more, based on 100 parts by mass of the rubber component. The content is preferably 10.0 parts by mass or less, and more preferably 6.0 parts by mass or less.

[0132] The rubber composition preferably contains stearic acid. In the above rubber composition, the content of stearic acid is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the rubber component.

[0133] As the stearic acid, any conventionally known product can be used, for example, products available from NOF Corp., Kao Corp., Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., and the like.

[0134] The rubber composition preferably contains zinc oxide. In the above rubber composition, the content of zinc oxide is preferably 0.5 parts by mass or more, more preferably 1.5 parts by mass or more, and preferably 6.0 parts by mass or less, more preferably 4.0 parts by mass or less, based on 100 parts by mass of the rubber component.

[0135] As the zinc oxide, any known zinc oxide can be used, for example, products available 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.

[0136] The rubber composition may contain wax. In the rubber composition, the wax content is preferably 0.5 parts by mass or more, more preferably 1.6 parts by mass or more, and preferably 8.0 parts by mass or less, more preferably 5.0 parts by mass or less, based on 100 parts by mass of the rubber component.

[0137] The wax is not particularly limited, and examples thereof include petroleum waxes, natural waxes, etc. Also, synthetic waxes obtained by refining or chemically treating multiple waxes can be used. These waxes may be used alone or in combination of two or more kinds.

[0138] Examples of petroleum waxes include paraffin wax and microcrystalline wax. Examples of natural waxes are not particularly limited as long as they are derived from resources other than petroleum, and include, for example, vegetable waxes such as candelilla wax, carnauba wax, Japan wax, rice wax, and jojoba wax; animal waxes such as beeswax, lanolin, and spermaceti; mineral waxes such as ozokerite, ceresin, and petrolactam; and refined products thereof. Examples of commercially available products include products from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Chemical Co., Ltd.

[0139] It is preferable to compound sulfur into the rubber composition in order to form an appropriate amount of crosslinked chains in the polymer chains and impart good performance.

[0140] In the rubber composition, the amount of sulfur is preferably 1.0 part by mass or more, more preferably 1.3 parts by mass or more, and even more preferably 1.6 parts by mass or more, based on 100 parts by mass of the rubber component. The amount is preferably 7.0 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 4.0 parts by mass or less.

[0141] 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 kinds.

[0142] 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 speed and crosslink density, but is preferably 0.1 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 1.7 parts by mass or more, based on 100 parts by mass of the rubber component. The upper limit is preferably 8.0 parts by mass or less, more preferably 5.0 parts by mass or less, and even more preferably 4.0 parts by mass or less.

[0143] The type of vulcanization accelerator is not particularly limited, and commonly used ones can be used. Examples of the vulcanization accelerator include thiazole-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-orthotolyl guanidine, and orthotolyl biguanidine. 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.

[0144] In addition to the above-mentioned components, the rubber composition may contain compounding agents generally used in the tire industry, such as materials such as a mold release agent.

[0145] The rubber composition can be produced, for example, by kneading the above-mentioned components using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanizing the mixture.

[0146] As for the kneading conditions, in the base kneading step in which additives other than the crosslinking agent (vulcanizing agent) and the vulcanization accelerator are kneaded, the kneading temperature is preferably 100°C or higher, more preferably 120°C or higher, and also preferably 180°C or lower, more preferably 170°C. In the finish kneading step in which the vulcanizing agent and the vulcanization accelerator are kneaded, the kneading temperature is preferably 80°C or higher, and also preferably 120°C or lower, more preferably 110°C or lower. In addition, the composition kneaded with the vulcanizing agent and the 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 also preferably 190°C or lower, more preferably 185°C or lower.

[0147] The rubber composition can be used for tires, shoe soles, flooring materials, vibration-proof materials, seismic isolation materials, butyl frames, belts, hoses, packings, drug stoppers, and other rubber industrial products, etc. In particular, it is preferable to use the rubber composition as a tire rubber composition since it has excellent tire performance such as wet grip performance.

[0148] The tire components to which the rubber composition is applied are not particularly limited, and include any tire components such as cap tread, sidewall, base tread, bead apex, clinch apex, inner liner, under tread, breaker topping, bright topping, etc. Among them, the rubber composition is preferably applied to the cap tread because of its excellent wet grip performance.

[0149] <Tires> The rubber composition can be suitably used for tires. Examples of tires include pneumatic tires and non-pneumatic tires, and among these, pneumatic tires are preferred. In particular, the rubber composition can be suitably used as summer tires (summer tires), winter tires (studless tires, snow tires, studded tires, etc.), all-season tires, etc. Tires can be used as passenger car tires, large passenger car tires, large SUV tires, heavy load tires such as trucks and buses, light truck tires, two-wheeled automobile tires, racing tires (high performance tires), etc. Among these, the rubber composition can be suitably used for passenger car tires and light truck tires.

[0150] A tire is manufactured by a normal method using the above 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 normal method to form an unvulcanized tire, which is then heated and pressurized in a vulcanizer to manufacture a tire. EXAMPLES

[0151] In the following, examples (embodiments) that are considered to be preferable for carrying out the present invention will be shown, but the scope of the present invention is not limited to the examples.

[0152] <Synthesis of nitrile oxide compounds having nitrile oxide groups and cationic groups (CNO-Py)> Compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic group) is synthesized according to the synthetic route shown in FIG.

[0153] (Compound S→Compound P1) Add a stir bar to a three-neck flask, add 2-hydroxy-1-naphthaldehyde (compound S) and DMF (N,N-dimethylformamide), and stir to dissolve. Add K2CO3 to the flask and stir for 1 hour. Add 2-(chloromethyl)pyridine hydrochloride to the mixture and stir to dissolve. Heat the solution in an oil bath and react at 100°C. After 3 hours, cool the solution to room temperature, dilute with ethyl acetate, and pour into a separatory funnel to separate with water and an aqueous NaCl solution. Collect the organic layer, dry with MgSO4, and remove the solvent with an evaporator. Recrystallize the resulting crude product from ethanol to obtain compound P1.

[0154] (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 the beaker of P1 and react at room temperature for 4 hours. Then add a large amount of water to the reaction solution to precipitate compound P2. Collect the precipitate and dry it to obtain compound P2.

[0155] (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 react. After completion of the dropping, 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 (nitrile oxide compound having a nitrile oxide group and a cationic group, CNO-Py).

[0156] Synthetic 1 From the H-NMR spectrum (FIG. 2) and TGA (FIG. 3), it is understood that compound P3 (a nitrile oxide compound having a nitrile oxide group and a cationic group) has been synthesized.

[0157] <Synthesis of nitrile oxide compounds having nitrile oxide groups and anionic groups (CNO-COOH)> Compound C4 (a nitrile oxide compound having a nitrile oxide group and an anionic group) is synthesized according to the synthetic route shown in FIG.

[0158] (Compound S→Compound C1) First, add a stir bar, 2-hydroxy-1-naphthaldehyde (compound S), K2CO3, DMF (N,N-dimethylformamide), and ethyl 6-bromohexanoate to a three-neck flask, 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 C1.

[0159] (Compound C1 → Compound C2) Compound C1 and LiOH are dissolved in a mixed solvent of THF: iPrOH: H2O = (4:2:1), and reacted at room temperature overnight. After the reaction is completed, the mixture is neutralized with hydrochloric acid and evaporated. The residue is diluted with water, and ethyl acetate is poured into a separatory funnel to separate the liquids. The ethyl acetate layer is dried with MgSO4, evaporated to dryness, and then dried in vacuum to obtain compound C2.

[0160] (Compound C2 → Compound C3) Add a stir bar, compound C2 and ethanol to a 500 ml beaker and stir to dissolve. Add an aqueous solution of CH3COONa·3H2O and NH2OH·HCl to the compound C2 solution and react at room temperature for 4 hours to obtain a precipitate. Filter the mixture to collect the precipitate and dry it in vacuum to obtain compound C3.

[0161] (Compound C3 → Compound C4) Add a stirrer, compound C3, and 2-propanol to a three-neck flask, place in an ice bath, and stir to disperse. Add an aqueous NaClO solution to the flask using a dropping funnel at 0-5°C and react. After the reaction is complete, adjust the pH to approximately 5 with HCl, and add a large amount of water to precipitate compound C4. Recrystallize the precipitate with ethanol / water to obtain the desired compound C4 (a nitrile oxide compound with a nitrile oxide group and an anionic group, CNO-COOH).

[0162] <Synthesis of modified polymer (A)> According to Table 1, the above compound P3 (nitrile oxide compound having a nitrile oxide group and a cationic group, CNO-Py) is added to SSBR or BR and kneaded at 70°C for 15 minutes, and the reaction is allowed to proceed during kneading to obtain modified polymer (A) (modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and a cationic group with a polymer (Py_SBR_K1, Py_SBR_K2, Py_SBR_K3, Py_BR_K1, Py_BR_K2, Py_BR_K3)).

[0163] <Synthesis of modified polymer (B)> According to Table 2, the above compound C4 (nitrile oxide compound having a nitrile oxide group and an anionic group, CNO-COOH) is added to SSBR or BR and kneaded at 70°C for 15 minutes, and the reaction is allowed to proceed during kneading to obtain modified polymer (B) (modified polymer obtained by reacting a nitrile oxide compound having a nitrile oxide group and an anionic group with a polymer (COOH_SBR_K1, COOH_SBR_K2, COOH_SBR_K3, COOH_BR_K1, COOH_BR_K2, COOH_BR_K3)).

[0164] <Synthesis of modified polymer (C)> According to Table 3, the above compound P3 is added to SSBR or BR and kneaded at 70°C for 15 minutes, and then the above compound C4 is added to the kneaded mixture and kneaded at 70°C for 15 minutes, and the reaction is allowed to proceed during kneading to obtain modified polymers (C) (Py_COOH_SBR_K1, Py_COOH_SBR_K2, Py_COOH_SBR_K3, Py_COOH_BR_K1, Py_COOH_BR_K2, Py_COOH_BR_K3) in which the anions and cations have been modified.

[0165] The SBR and BR in Tables 1, 2, and 3 use the following materials. SBR (SSBR): HPR840 (S-SBR) manufactured by JSR Corporation BR: BR150B (cis content 96% by mass) manufactured by Ube Industries, Ltd.

[0166] The double bond modification rates and nitrile oxide compound reaction rates in Tables 1, 2 and 3 are defined below and are measured by the following method. (Double bond modification rate (%)) = [amount of carbon-carbon double bonds reacted with nitrile oxide compounds / (amount of remaining carbon-carbon double bonds + amount of carbon-carbon double bonds reacted with nitrile oxide compounds)] x 100 (Reaction rate of nitrile oxide compound (%)) = (amount of nitrile oxide compound reacted with double bond) / (amount of nitrile oxide compound charged) × 100

[0167] (1) Double bond modification rate The ratio of nitrile oxide compounds added to the carbon-carbon double bonds in the polymer was measured by IR. 1 H-NMR measurement and 13 Calculated by C-NMR measurement.

[0168] (2) Reaction rate of nitrile oxide compound IR measurement, 1 H-NMR measurement and 13 Determined by C-NMR measurement.

[0169] [Table 1]

[0170] [Table 2]

[0171] [Table 3]

[0172] (Extension test) The modified SBR produced by kneading addition (SBR and the above compounds P3 and C4 are kneaded for 15 minutes each while controlling the rotation speed to 50 rpm and the temperature to 70°C or less, and the SBR is reacted with P3 and C4 during kneading to produce the modified SBR) is pressed at 70°C for 10 minutes to obtain a 1 mm thick sheet, and an elongation test is performed using the sheet. Specifically, a biaxial extension tester (manufactured by IS Giken Co., Ltd.) is used to perform an extension test at 23° C. and an extension rate of 100 mm / min. Figure 7 shows the relationship between strain and stress.

[0173] Tables 1 and 2 show that the modified polymer (B) (a modified polymer obtained by reacting a polymer with a nitrile oxide compound having a nitrile oxide group and an anionic group) has a double bond modification rate of 0.4 to 4.8% and a nitrile oxide compound reaction rate of 20.0 to 27.8%, whereas the modified polymer (A) (a modified polymer obtained by reacting a polymer with a nitrile oxide compound having a nitrile oxide group and a cationic group) has a double bond modification rate of 2.2 to 15.5% and a nitrile oxide compound reaction rate of 83.3 to 95.0%, indicating that the use of a nitrile oxide compound having a nitrile oxide group and a cationic group improves the nitrile oxide compound reaction rate and enables the double bond modification rate to be controlled.

[0174] Table 3 shows that the double bond modification rate of the nitrile oxide compound having a nitrile oxide group and an anionic group is improved by using a nitrile oxide compound having a nitrile oxide group and a cationic group together with a nitrile oxide compound having a nitrile oxide group and an anionic group.

[0175] <Preparation of Rubber Composition> The various chemicals used are explained below. SBR: HPR840 (S-SBR) manufactured by JSR Corporation BR: BR150B (cis content 96% by mass) manufactured by Ube Industries, Ltd. Carbon black: Show Black N220 (N2SA:111m) manufactured by Cabot Japan Co., Ltd. 2 / g, DBP absorption: 115ml / 100g) Silica: Ultrasil VN3 (N2SA: 175m) manufactured by Evonik Degussa 2 / g) Silane coupling agent: Si266 manufactured by Evonik Degussa CNO-Py: Synthesis of nitrile oxide compounds having the above nitrile oxide group and cationic group CNO-COOH: Synthesis of nitrile oxide compounds having the above nitrile oxide group and anionic group Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccela NS (N-tert-butyl-2-benzothiazylsulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccelaer D (1,3-diphenylguanidine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0176] (Production of Rubber Composition) According to the formulation shown in Tables 4 and 5, the CNO materials (CNO-COOH, CNO-Py), sulfur, and chemicals other than the vulcanization accelerator are kneaded for 5 minutes under the condition of 130°C using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded product. To the kneaded mixture, CNO materials (CNO-COOH, CNO-Py) are added, and the mixture is kneaded for 15 minutes under the condition of 70° C. 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.

[0177] The vulcanized rubber composition was subjected to the following physical property measurements and evaluations. The results are shown in Tables 4 and 5. The reference comparative examples are as follows. Table 4: Comparative Example 1-1 Table 5: Comparative Example 2-1

[0178] <Crack growth resistance> A flex crack growth test was conducted in accordance with JIS K6260:2017, in which the vulcanized rubber composition (sheet) was bent by repeatedly stretching by 70% 1 million times, and the length of the crack that developed was then measured. The reciprocal of the measured value of the reference comparative example was set to 100 and expressed as an index. The larger the index, the smaller the crack and the better the crack growth resistance.

[0179] <Tensile test> A dumbbell No. 7 test piece is prepared and a tensile test is performed at a test temperature of 23°C and a tensile test speed of 200mm / min using a tensile tester (RTG-1210) manufactured by A&D Co., Ltd. The larger the breaking strength TB and breaking elongation EB, the better the fracture properties (durability). TB: represents the fracture strength 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 from the following formula is the elongation at break, EB (%). Chuck distance at break (mm) / initial chuck distance (20mm) x 100

[0180] <Wet grip performance> For the vulcanized rubber composition, tan δ is measured using a viscoelasticity spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.) under conditions of a frequency of 10 Hz, a strain of 0.1%, and a temperature of 0° C. The tan δ of the reference comparative example is expressed as an index of 100. A larger index value indicates better wet grip performance.

[0181] [Table 4]

[0182] [Table 5]

[0183] According to Table 4, when SBR or BR is mixed with materials such as a nitrile oxide compound (cationic group, CNO-Py) or a nitrile oxide compound (anionic group, CNO-COOH), CNO-Py-modified SBR, CNO-Py-modified BR, CNO-COOH-modified SBR, and CNO-COOH-modified BR are produced during mixing.

[0184] The present invention (1) is a polymer modifying agent having a nitrile oxide group and a cationic group.

[0185] The present invention (2) relates to the polymer modifying agent according to the present invention (1), in which the cationic group is an amino group.

[0186] The present invention (3) relates to the polymer modifying agent according to the present invention (2), in which the amino group is a pyridine group.

[0187] The present invention (4) is a modified polymer obtained by reacting a polymer modifier having a nitrile oxide group and a cationic group, which is any combination of any of the present inventions (1) to (3), with a polymer.

[0188] The present invention (5) relates to the modified polymer according to the present invention (4), wherein the polymer is a diene rubber.

[0189] The present invention (6) is a rubber composition containing the modified polymer according to the present invention (4) or (5).

[0190] The present invention (7) is the rubber composition according to the present invention (6), further comprising a modified polymer (B) obtained by reacting a polymer modifier (B) having a nitrile oxide group and an anionic group with a polymer.

[0191] The present invention (8) is a tire using the rubber composition according to the present invention (6) or (7).

Claims

1. Modifier for polymers having nitrile oxide groups and cationic groups.

2. 2. The polymer modifying agent according to claim 1, wherein the cationic group is an amino group.

3. 3. The polymer modifying agent according to claim 2, wherein the amino group is a pyridine group.

4. A modified polymer obtained by reacting the polymer modifier having a nitrile oxide group and a cationic group according to claim 1 with a polymer.

5. The modified polymer of claim 4, wherein the polymer is a diene-based rubber.

6. A rubber composition comprising the modified polymer according to claim 4.

7. The rubber composition according to claim 6, further comprising a modified polymer (B) obtained by reacting a polymer modifier (B) having a nitrile oxide group and an anionic group with a polymer.

8. A tire using the rubber composition according to claim 6.

Images