Phenylboronic acid compounds, modified polymers, polymer compositions, and tires

Abstract

Provided are a phenylboronic acid compound that can impart to a polymer the ability to reversibly change physical properties when exposed to water, a polymer that exhibits reversible changes in physical properties when exposed to water, and a polymer composition and tire that use said polymer. The present invention relates to a phenylboronic acid compound represented by the following formula (1-1). (R21 and R22 are the same or different and are divalent hydrocarbon groups which may have a substituent, and may contain a heteroatom. R23–R25 are the same or different and are hydrogen atoms or monovalent hydrocarbon groups which may have a substituent, and may contain a heteroatom. m is an integer of 1–5.)

Description

Technical Field

[0001] The present disclosure relates to a phenylboronic acid compound, a modified polymer, a polymer composition, and a tire.

Background Art

[0002] Various polymers are used in products such as tires, and it is desired to impart various performances by the polymers.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The present disclosure solves the above problems, and provides a phenylboronic acid compound that can impart a function of reversibly changing physical properties with water to a polymer, a polymer that exhibits a reversibly change in physical properties with water, and a polymer composition and a tire using the polymer.

Means for Solving the Problems

[0004] The present disclosure relates to a phenylboronic acid compound represented by the following formula (1-1).

Chemical Formula

Effects of the Invention

[0005] According to the present disclosure, since it is the phenylboronic acid compound represented by the formula (1-1), a function of reversibly changing physical properties with water can be imparted to a polymer.

Brief Description of the Drawings

[0006] [Figure 1] This is an example of a synthesis in which a phenylboronic acid compound represented by formula (1) is synthesized. [Figure 2] This is an example of the 1H-NMR spectrum of the synthesized product. [Figure 3] This is an example of a synthesis that shows a pathway in which a modified polymer is synthesized by the reaction of a phenylboronic acid compound with a polymer. [Figure 4] These are examples of IR spectra and 1H-NMR spectra of synthetic products. [Modes for carrying out the invention]

[0007] <Modified polymer> This disclosure relates to a modified polymer modified with a phenylboronic acid compound represented by the following formula (1). The modified polymer can exhibit reversible changes in physical properties when exposed to water.

[0008] The reason why the aforementioned effects are obtained is not entirely clear, but it is presumed to be due to the following mechanism. When a modified polymer, obtained by reacting a polymer with a phenylboronic acid compound represented by formula (1), is dried, it undergoes reversible dehydration condensation of three molecules to generate boroxine (boroxine crosslinks). Subsequently, upon contact with water, the generated boroxine crosslinks decompose. Therefore, during drying, a polymer with boroxine crosslinks is formed, while during water swelling, the boroxine crosslinks decompose, forming the modified polymer. Consequently, the modified polymer can exhibit reversible changes in physical properties due to water. Furthermore, for example, if the modified polymer is used in a tire, it is presumed that the elastic modulus decreases upon contact with water, increasing losses on wet surfaces and improving wet grip performance.

[0009] The aforementioned modified polymer is a polymer modified with a phenylboronic acid compound represented by the following formula (1). [ka] (R 11is a monovalent hydrocarbon group which may be the same or different and may have a substituent, and may contain a hetero atom. n is an integer of 1 to 5.)

[0010] In formula (1), R 11 Examples of the monovalent hydrocarbon group constituting the skeleton of include linear, cyclic or branched alkyl groups, alkenyl groups, aryl groups, aralkyl groups, etc., and an alkyl group is particularly preferred. The carbon number of R 11 is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, and is preferably 30 or less, more preferably 20 or less, still more preferably 10 or less, and particularly preferably 6 or less. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group, etc. can be mentioned.

[0011] In the above formula (1), the substituent in R 11 may be added to the skeleton of the monovalent hydrocarbon group constituting the skeleton of R 11 or introduced into the skeleton. The substituent is not particularly limited, and known groups can be mentioned. For example, alkoxy groups having 1 to 4 carbon atoms such as methoxy group, ethoxy group, butoxy group, halogen atoms such as chlorine, bromine, iodine, fluorine, aryl groups having 6 to 12 carbon atoms such as phenyl group, naphthyl group, biphenyl group, oxo group (=O), hydroxy group, carboxyl group, carbonyl group, polar groups such as amino group, acetyl group, amide group, imide group, etc. are exemplified. From the viewpoint of reactivity with the polymer, the substituent is preferably a carboxyl group, an amino group, a thiol group, etc.

[0012] From the viewpoint of more obtaining the function of reversible physical property change by water, a group having a nitrogen atom is preferred, and an amino group is more preferred.

[0013] The reason for obtaining the above-mentioned action and effect is not necessarily clear, but it is presumed to be due to the following mechanism. As described above, when a modified polymer obtained by reacting with a phenylboronic acid compound represented by formula (1) is dried, it undergoes reversible dehydration condensation of three molecules to generate boroxine (boroxine crosslinks). Subsequently, when it comes into contact with water, the generated boroxine crosslinks decompose, thus providing the function of reversible property change due to water. Furthermore, while ordinary phenylboroxine requires heating for dehydration and recondensation of three molecules after hydrolysis, in the case of phenylboronic acid compounds containing nitrogen atoms, particularly phenylboronic acid compounds where the nitrogen atom is located near the phenylboroxine group, dehydration and recondensation of three molecules is possible even at room temperature. Therefore, it is presumed that by using the above-mentioned modified polymer, the function of reversible property change due to water can be better imparted.

[0014] In the above equation (1), R 11 When the compound has a nitrogen atom, it is preferable that the nitrogen atom and the boron atom of the phenylboronic acid compound represented by formula (1) are bonded via 1 to 6 carbon atoms, from the viewpoint of obtaining the function of reversible property changes by water. The number of carbon atoms involved is preferably 2 to 5, more preferably 2 to 4, and even more preferably 2 to 3. For example, the phenylboronic acid compound C shown in Figure 1, described later, is a compound in which the nitrogen atom and the boron atom are bonded via 3 carbon atoms.

[0015] R 11 Examples of substituent amino groups in this compound include primary amino groups (-NH2) and secondary amino groups (-NH2). 1 ), tertiary amino group (-NR 1 R 2 ) are examples of the above R 1 and R 2 Examples of R include alkyl groups, phenyl groups, aralkyl groups, etc. 1 , R 2 The number of carbon atoms is preferably 1 to 8. The amino group may also be an ammonium base, for example, a tertiary ammonium base, a quaternary ammonium base, etc. The amino group may also be a divalent amino group. Examples of the divalent amino group include -N(H)- and -N(R 3 )- is an example. The aforementioned R 3Examples of R include alkyl groups, phenyl groups, aralkyl groups, etc. 3 The number of carbon atoms is preferably 1 to 8. In the case of a divalent amino group, for example, R 11 It is introduced into the framework.

[0016] R 11 Examples of heteroatoms in this compound include nitrogen atoms, oxygen atoms, and sulfur atoms. Among these, nitrogen atoms are preferred from the viewpoint of obtaining a more effective result.

[0017] In formula (1), n ​​is preferably 1 to 4, more preferably 1 to 3, even more preferably 1 to 2, and particularly preferably 1, from the viewpoint of obtaining a better effect.

[0018] From the viewpoint of obtaining a more effective result, among the phenylboronic acid compounds represented by formula (1) above, the compound represented by the following formula (1-1) is preferred. [ka] (R 21 and R 22 R is a divalent hydrocarbon group which may have substituents, either identical or different, and may contain heteroatoms. 23 ~R 25 m is a monovalent hydrocarbon group that may have a hydrogen atom or substituents, and may also contain a heteroatom. m is an integer from 1 to 5.

[0019] The reason why the aforementioned effects are obtained is not entirely clear, but it is presumed to be due to the following mechanism. As mentioned above, when ordinary phenylboroxine is hydrolyzed, heating is required for the dehydration and recondensation of three molecules. However, in the case of the phenylboronic acid compound shown in formula (1-1), the dehydration and recondensation of three molecules is possible even at room temperature. Therefore, it is presumed that by using the modified polymer, the function of reversible property changes due to water can be better imparted.

[0020] In equation (1-1), R 21 and R 22The divalent hydrocarbon groups constituting the skeleton may be linear, cyclic, or branched, and examples include alkylene groups, alkenylene groups, cycloalkylene groups, cycloalkylalkylene groups, arylene groups, and aralkylene groups. 21 and R 22 The number of carbon atoms is preferably 1 to 30, more preferably 1 to 15, even more preferably 1 to 8, and particularly preferably 1 to 5. Specifically, examples include methylene groups, ethylene groups, trimethylene groups, tetramethylene groups, pentamethylene groups, hexamethylene groups, and the like.

[0021] R 21 and R 22 The substituents in R 21 and R 22 The substituent may be added to or introduced into the skeleton of the divalent hydrocarbon group that constitutes the skeleton. The substituent is not particularly limited, for example, the R 11 Examples of substituents similar to those in R include: 21 and R 22 Regarding heteroatoms in the above, for example, R 11 Examples similar to heteroatoms include the following.

[0022] R 23 ~R 25 Examples of monovalent hydrocarbon groups that constitute the skeleton include the aforementioned R 11 Examples include monovalent hydrocarbon groups similar to those that make up the skeleton. 23 ~R 25 The substituents in R 23 ~R 25 The substituent may be added to or introduced into the skeleton of the monovalent hydrocarbon group constituting the skeleton. The substituent is not particularly limited, for example, the R 11 Examples of substituents similar to those in R include: 23 ~R 25 Regarding heteroatoms in the above, for example, R 11 Examples similar to heteroatoms include the following.

[0023] Among them, R 23From the viewpoint of obtaining a more effective result, a hydrogen atom or a monovalent hydrocarbon group is preferred, and a hydrogen atom is more preferred. R 24 From the viewpoint of obtaining a more effective result, a hydrogen atom or a monovalent hydrocarbon group is preferred, and a hydrogen atom is more preferred. R 25 From the viewpoint of obtaining a more effective result, a hydrogen atom or a monovalent hydrocarbon group is preferred, and a hydrogen atom is more preferred.

[0024] In formula (1-1), from the viewpoint of obtaining a better effect, m is preferably 1 to 4, more preferably 1 to 3, even more preferably 1 to 2, and particularly preferably 1.

[0025] The phenylboronic acid compound represented by formula (1) can be synthesized by known methods. An example of a synthesis method for the phenylboronic acid compound is described below, but the phenylboronic acid compound is not limited to those obtained by this synthesis method, and includes compounds obtained by any synthesis method that is feasible.

[0026] For example, a predetermined phenylboronic acid compound and the R 11 By reacting a compound that can be introduced with the group shown by formula (1), a phenylboronic acid compound represented by formula (1) can be synthesized.

[0027] The above reaction is usually carried out in a solvent. The solvent used in the reaction is not particularly limited, and any solvent that allows the reaction to proceed can be appropriately selected. Examples include ethers such as ethylene glycol dimethyl ether, tetrahydrofuran, and 1,4-dioxane, aromatic hydrocarbons such as toluene, water, and mixtures thereof. A known catalyst can be used in the reaction as appropriate, such as a palladium catalyst. The amount of catalyst used in the reaction can be appropriately selected. The phenylboronic acid compound used in the reaction and the aforementioned R 11The mixing ratio of the compound into which the group indicated by can be introduced should be appropriately selected within the range in which the reaction proceeds. The reaction temperature is usually in the range of 50 to 110°C, and the reaction time is usually in the range of 1 to 24 hours. After the reaction is complete, the target product can be isolated by work-up operations such as extracting the reaction mixture with an organic solvent and concentrating the organic layer, and can be further purified by recrystallization, chromatography, etc., if necessary.

[0028] To illustrate with a specific example of compound synthesis, for instance, phenylboronic acid compound C can be synthesized using the synthesis route shown in Figure 1.

[0029] As shown in Figure 1, for example, phenylboronic acid compound C is synthesized by reacting phenylboronic acid compound B and an amine compound overnight at room temperature in a solvent (methanol), reducing it with sodium borohydride (NaBH4), and deprotecting it with hydrochloric acid (HCl) at the Boc (tert-butoxycarbonyl group) level.

[0030] The polymer constituting the backbone of the modified polymer is not particularly limited, and any polymer can be used.

[0031] The polymer may be an unmodified polymer or a modified polymer. The modified polymer can be any polymer having a functional group. Examples include end-modified polymers (end-modified polymers having the functional group at the end) in which at least one end of the polymer is modified with a compound having the functional group (modifying agent), main-chain modified polymers having the functional group in the main chain, main-chain end-modified polymers having the functional group in both the main chain and the end (for example, a main-chain end-modified polymer having the functional group in the main chain and at least one end modified with the modifying agent), and end-modified polymers that are modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule, and into which hydroxyl groups or epoxy groups are introduced.

[0032] Examples of the above-mentioned functional groups include amino groups, amide groups, silyl groups, alkoxysilyl groups, isocyanate groups, imino groups, imidazole groups, urea groups, ether groups, carbonyl groups, oxycarbonyl groups, mercapto groups, sulfide groups, disulfide groups, sulfonyl groups, sulfinyl groups, thiocarbonyl groups, ammonium groups, imide groups, hydrazo groups, azo groups, diazo groups, carboxyl groups, nitrile groups, pyridyl groups, alkoxy groups, hydroxyl groups, oxy groups, epoxy groups, and the like. These functional groups may have substituents. Among these, amino groups, epoxy groups, and carboxyl groups are preferred from the viewpoint of reactivity with the phenylboronic acid compound represented by formula (1).

[0033] Examples of the above-mentioned polymers include polymers having carbon-carbon double bonds. Examples of polymers containing carbon-carbon double bonds include diene rubbers. Examples of diene rubbers 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 rubbers and fluororubbers. Among these, isoprene rubbers, NBRs, BRs, and SBRs are preferred from the viewpoint of reactivity with the phenylboronic acid compound represented by formula (1), and isoprene rubbers, NBRs, and SBRs are more preferred. These may be used individually or in combination of two or more.

[0034] Examples of isoprene-based rubbers include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. For NR, common types used in the rubber industry can be used, such as SIR20, RSS#3, and TSR20. For IR, there are no particular limitations; common types used in the rubber industry can be used, such as IR2200. Examples of modified NR include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). 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. As exemplified above, isoprene-based rubbers may be unmodified isoprene-based rubbers or modified isoprene-based rubbers (such as ENR). These may be used individually or in combination of two or more types.

[0035] From the viewpoint of reactivity with the phenylboronic acid compound represented by formula (1) above, modified isoprene rubber is preferred. Examples of functional groups to be imparted to the modified isoprene rubber include the aforementioned functional groups, among which epoxy groups and carboxyl groups are preferred.

[0036] BR is not particularly limited, and for example, high-cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, and BR synthesized using a rare-earth catalyst (rare-earth BR) can be used. These may be used alone or in combination of two or more. Among these, high-cis BR with a cis content of 90% by mass or more is preferred for improved wear resistance. BR may be unmodified BR or modified BR (such as carboxylic acid-modified BR). These may be used alone or in combination of two or more.

[0037] From the viewpoint of reactivity with the phenylboronic acid compound represented by formula (1) above, modified BR is preferred. Examples of functional groups that can be added to modified BR include the aforementioned functional groups, among which carboxyl groups, amino groups, and epoxy groups are preferred.

[0038] For example, products from companies such as Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Corporation can be used as BRs.

[0039] The type of SBR is not particularly limited; for example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc., can be used. These may be used individually or in combination of two or more types. The SBR may be unmodified SBR or modified SBR (such as carboxylic acid-modified SBR). These may be used individually or in combination of two or more types.

[0040] From the viewpoint of reactivity with the phenylboronic acid compound represented by formula (1) above, modified SBR is preferred. Examples of functional groups to be added to the modified SBR include the aforementioned functional groups, among which carboxyl groups, amino groups, and epoxy groups are preferred.

[0041] The styrene content of SBR is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. Furthermore, the styrene content is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained. In this specification, the styrene content of SBR is as follows: 1 It is calculated by 1H-NMR measurement.

[0042] The vinyl content of SBR is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. The vinyl content is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained. The vinyl content (amount of 1,2-bonded butadiene units) can be measured by infrared absorption spectroscopy.

[0043] For example, SBR manufactured and sold by companies such as Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, and Nippon Zeon Co., Ltd. can be used.

[0044] In addition to the aforementioned diene-based rubbers, butyl-based rubbers, and fluororubber polymers, liquid polymers that are in a liquid state at room temperature (25°C) (such as liquid resins, liquid diene-based polymers, and liquid farnesene-based polymers) can also be used as the polymers mentioned above.

[0045] Examples of liquid resins include terpene resins (including terpene phenol resins and aromatically modified terpene resins), rosin resins, styrene resins, C5 resins, C9 resins, C5 / C9 resins, dicyclopentadiene (DCPD) resins, coumarone-indene resins (including coumarone and indene-only resins), phenolic resins, olefin resins, polyurethane resins, and acrylic resins. Hydrogenated versions of these resins can also be used.

[0046] Examples of liquid diene polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), liquid styrene-butadiene-styrene block copolymer (liquid SBS block polymer), liquid styrene-isoprene-styrene block copolymer (liquid SIS block polymer), liquid farnesene polymer, and liquid farnesene-butadiene copolymer. These polymers may have polar groups attached to their ends or main chains. Hydrogenated versions of these polymers can also be used.

[0047] Liquid farnesene polymers are polymers obtained by polymerizing farnesene and have constituent 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]

[0048] The liquid farnesene polymer may be a farnesene homopolymer (farnesene homopolymer) or a farnesene-vinyl monomer copolymer (farnesene-vinyl monomer copolymer). These may be used individually or in combination of two or more. Among these, the farnesene-vinyl monomer copolymer is preferred.

[0049] 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)dimethylaminoethyl ether, 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 individually or in combination of two or more. Among these, butadiene is preferred. In other words, a copolymer of farnesene and butadiene (farnesene-butadiene copolymer) is preferred as the farnesene-vinyl monomer copolymer.

[0050] In farnesene-vinyl monomer copolymers, the mass-based copolymerization ratio (farnesene / vinyl monomer) of farnesene to vinyl monomer is preferably 40 / 60 to 90 / 10.

[0051] Liquid farnesene polymers with a weight-average molecular weight (Mw) of 3,000 to 300,000 are preferably used. The Mw of the liquid farnesene polymer is preferably 8,000 or more, more preferably 10,000 or more, and also preferably 100,000 or less, more preferably 60,000 or less, and even more preferably 50,000 or less.

[0052] In this specification, the weight-average molecular weight (Mw) can be determined by converting the measured values ​​obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation) to standard polystyrene equivalents.

[0053] As the polymers mentioned above, resins (resins that are solid at room temperature (25°C)) can also be used. Examples of the above-mentioned resins (resins that are solid at room temperature (25°C)) include aromatic vinyl polymers, coumarone indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, and acrylic resins that are solid at room temperature (25°C). The resins may also be hydrogenated. These may be used individually or in combination of two or more types.

[0054] The softening point of the above resin is preferably 50°C or higher, more preferably 55°C or higher, and even more preferably 60°C or higher. The upper limit is preferably 160°C or lower, more preferably 150°C or lower, and even more preferably 145°C or lower. Within the above range, better tire performance, such as wet grip performance, tends to be obtained. The softening point of the above resin is the temperature at which the sphere descends when the softening point specified in JIS K6220-1:2001 is measured using a ring-type softening point measuring device.

[0055] The above-mentioned aromatic vinyl polymer is a polymer containing aromatic vinyl monomers as constituent units. Examples include resins obtained by polymerizing α-methylstyrene and / or styrene, specifically, homopolymers of styrene (styrene resin), homopolymers of α-methylstyrene (α-methylstyrene resin), copolymers of α-methylstyrene and styrene, copolymers of styrene and other monomers.

[0056] The above-mentioned coumarone-indene resin is a resin that contains coumarone and indene as the main monomer components that constitute the resin's backbone (main chain). Other monomer components that may be included in the backbone besides coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0057] The coumarone resin described above is a resin that contains coumarone as the main monomer component that constitutes the resin's backbone (main chain).

[0058] The above-mentioned indene resin is a resin that contains indene as the main monomer component that constitutes the resin's backbone (main chain).

[0059] As the phenolic resin mentioned above, known polymers such as those obtained by reacting phenol with aldehydes such as formaldehyde, acetaldehyde, and furfural using an acid or alkali catalyst can be used. Among these, those obtained by reaction with an acid catalyst (such as novolac-type phenolic resins) are preferred.

[0060] Examples of the rosin resins mentioned above include natural rosin, polymerized rosin, modified rosin, their ester compounds, and rosin-based resins represented by their hydrogenated products.

[0061] Examples of the above petroleum resins include C5 resins, C9 resins, C5 / C9 resins, dicyclopentadiene (DCPD) resins, and hydrogenated versions thereof. Among these, DCPD resins and hydrogenated DCPD resins are preferred.

[0062] The above-mentioned terpene resins are polymers that contain terpenes as constituent units. Examples include polyterpene resins obtained by polymerizing terpene compounds, and aromatically modified terpene resins obtained by polymerizing terpene compounds and aromatic compounds. As aromatically modified terpene resins, terpene-phenol resins made from terpene compounds and phenolic compounds, terpene-styrene resins made from terpene compounds and styrene compounds, and terpene-phenol-styrene resins made from terpene compounds, phenolic compounds, and styrene compounds can also be used. Examples of terpene compounds include α-pinene and β-pinene, examples of phenolic compounds include phenol and bisphenol A, and examples of aromatic compounds include styrene compounds (styrene, α-methylstyrene, etc.).

[0063] The above-mentioned acrylic resin is a polymer containing acrylic monomers as constituent units. Examples include styrene-acrylic resins such as styrene-acrylic resin, which have carboxyl groups and are obtained by copolymerizing an aromatic vinyl monomer component with an acrylic monomer component. Among these, solvent-free carboxyl group-containing styrene-acrylic resins can be suitably used.

[0064] The reaction process between the phenylboronic acid compound represented by formula (1) and the polymer is not particularly limited and can be carried out using known methods. It may be carried out in a solvent such as an organic solvent in water, or without a solvent. The solvent is not particularly limited, but it is preferable that the phenylboronic acid compound and the polymer are both easily soluble in it. Specific examples of solvents include those mentioned above. The reaction temperature and time can be appropriately set according to the phenylboronic acid compound and the polymer, allowing the reaction to proceed.

[0065] To illustrate with specific examples of compound synthesis, modified polymers A to D can be synthesized, for example, using the synthesis route shown in Figure 3.

[0066] Specifically, for example, phenylboronic acid compound A or C shown in Figure 3 is dissolved in a solvent with epoxidized natural rubber (ENR), NBR having an amino group (amine-modified NBR), SBR having a carboxyl group (carboxylic acid-modified SBR), or liquid polyisoprene modified with a carboxyl group. The prepared solution is stirred and reacted under appropriate temperature conditions. After the reaction is complete, the solution containing the product is precipitated in methanol and dried to obtain the target reaction product (a polymer modified with a phenylboronic acid compound represented by formula (1) (modified polymers A to D)).

[0067] The modified polymer may be either a modified polymer that is in a solid state at 25°C or a modified polymer that is in a liquid state at 25°C. Examples of modified polymers that are solid at 25°C include modified polymers of the aforementioned diene rubbers, butyl rubbers, and fluororubbers, which are solid at room temperature (25°C). In particular, it is desirable that the modified polymer is solid at 25°C and has a weight-average molecular weight (Mw) of 10,000 or more. Examples of modified polymers that are liquid at 25°C include the aforementioned liquid resins, liquid diene polymers, liquid farnesene polymers, and other liquid polymers that are liquid at room temperature (25°C).

[0068] <Polymer composition> The polymer composition includes a modified polymer modified with a phenylboronic acid compound represented by formula (1). When this polymer composition is used, it is provided with the function of reversible property changes due to water. The polymer composition may include any form of the modified polymer described above. That is, the polymer composition may include a composition containing at least one of the following: a modified polymer of a polymer that is solid at room temperature (25°C), such as the aforementioned diene rubber, butyl rubber, or fluororubber; or a modified polymer of a liquid polymer that is liquid at room temperature (25°C), such as the aforementioned liquid resin, liquid diene polymer, or liquid farnesene polymer. For example, when the polymer composition is used as a tire component, the elastic modulus decreases upon contact with water, increasing losses on wet surfaces, thus improving wet grip performance.

[0069] In the polymer composition, the content of the modified polymer modified with the phenylboronic acid compound represented by formula (1) in 100% by mass of the polymer components is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The upper limit is not particularly limited, but is preferably 70% by mass or less, more preferably 50% by mass or less, and even more preferably 30% by mass or less. When the content is within the above range, the effect tends to be favorably obtained.

[0070] The polymer composition may also contain other polymers besides the modified polymer modified with the phenylboronic acid compound represented by formula (1). Examples of other polymers include the aforementioned diene rubber, butyl rubber, and fluororubber.

[0071] If the polymer composition contains polymers other than the modified polymer modified with the phenylboronic acid compound represented by formula (1), the content of the other polymers in 100% by mass of the polymer component is not particularly limited, but is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The upper limit is not particularly limited, but is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. Within the above range, the effect tends to be favorably obtained.

[0072] In the polymer composition described above, the "polymer component" refers to a component that contributes to crosslinking, and generally, the polymer component is a polymer with a weight-average molecular weight (Mw) of 10,000 or more that is not extracted by acetone. Furthermore, the "content of the modified polymer modified with the phenylboronic acid compound represented by formula (1) in 100% by mass of the polymer component" and the "content of other polymers in 100% by mass of the polymer component" mean the "content of the modified polymer modified with the phenylboronic acid compound represented by formula (1)" and the "content of other polymers" that correspond to the polymer component, in 100% by mass of such a polymer component.

[0073] The polymer composition preferably contains a filler. As the filler, inorganic fillers such as silica, carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica; poorly dispersible fillers; and other fillers known in the rubber field can be used. From the viewpoint of tire performance when applied to tire components, silica and carbon black are preferred.

[0074] In the polymer composition, the total amount of filler 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, per 100 parts by mass of the polymer component. The upper limit is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, and even more preferably 160 parts by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained.

[0075] Examples of usable silica include dry-process silica (anhydrous silica) and wet-process silica (hydrated silica). Among these, wet-process silica is preferred because it contains a large number of silanol groups. Examples of silica products that can be used include those from Degussa, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Ltd., and Tokuyama Corporation.

[0076] The nitrogen adsorption specific surface area (N2SA) of silica is preferably 10 m². 2 / g or more, more preferably 20m 2 / g or more, more preferably 30m 2 It is 1 / g or more. Furthermore, the upper limit of N2SA in silica is not particularly limited, but preferably 300m 2 / g or less, more preferably 275m 2 / g or less, more preferably 250m 2 It is less than / g. Within the above range, tire performance such as wet grip performance tends to be better. In this specification, the N2SA of silica is the value measured by the BET method in accordance with ASTM D3037-93.

[0077] In the polymer composition, the silica content 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, per 100 parts by mass of the polymer component. The upper limit is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, and even more preferably 160 parts by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained.

[0078] If silica is included, a silane coupling agent may be added together with the silica. As for usable silane coupling agents, any silane coupling agent that has been conventionally used in combination with silica in the rubber industry can be used, and is not particularly limited. For example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3- Examples include sulfide-based compounds such as dimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyltetrasulfide, and 3-triethoxysilylpropyl methacrylate monosulfide; mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z; vinyl-based compounds such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based compounds such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based compounds such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products from companies such as Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azumax Co., Ltd., and Toray Dow Corning Co., Ltd. can be used. These may be used individually or in combination of two or more types. Among these, sulfide-based and mercapto-based products are preferred.

[0079] In the polymer composition, the content of the silane coupling agent is preferably 3 parts by mass or more, and more preferably 6 parts by mass or more, per 100 parts by mass of silica. Furthermore, the content is preferably 20 parts by mass or less, and more preferably 15 parts by mass or less.

[0080] Suitable carbon blacks include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These can be used individually or in combination of two or more types. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Shin-Nippon Chemical Carbon Co., Ltd., and Columbia Carbon Corporation.

[0081] The nitrogen adsorption specific surface area (N2SA) of carbon black is preferably 10 m². 2 / g or more, more preferably 20m 2 / g or more, more preferably 30m 2 It is 1 / g or more. Furthermore, the upper limit of N2SA in silica is not particularly limited, but preferably 300m 2 / g or less, more preferably 275m 2 / g or less, more preferably 250m 2 It is less than / g. Within the above range, tire performance such as wet grip performance tends to be better. In this specification, the specific surface area for nitrogen adsorption of carbon black is determined according to JIS K6217-2:2001.

[0082] In the polymer composition, the carbon black content 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, per 100 parts by mass of the polymer component. The upper limit is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, and even more preferably 160 parts by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained.

[0083] The polymer composition may also contain a plasticizer. Here, a plasticizer is a material that imparts plasticity to the polymer component, and examples include a liquid plasticizer (a plasticizer that is in a liquid state at room temperature (25°C)) and a resin (a resin that is in a solid state at room temperature (25°C)).

[0084] In the polymer composition, the plasticizer content (total amount of plasticizer) 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, per 100 parts by mass of the polymer component. The upper limit is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 90 parts by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained.

[0085] The liquid plasticizers (plasticizers that are in a liquid state at room temperature (25°C)) that can be used in polymer compositions are not particularly limited and include oils, liquid polymers (such as the aforementioned liquid resins, liquid diene polymers, and liquid farnesene polymers). Here, as liquid polymers, in addition to the aforementioned liquid resins, liquid diene polymers, and liquid farnesene polymers, modified polymers obtained by reacting such liquid resins with a phenylboronic acid compound represented by formula (1) can also be mentioned. These liquid plasticizers may be used alone or in combination of two or more.

[0086] In the polymer composition, the liquid plasticizer content 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, per 100 parts by mass of the polymer component. The upper limit is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 90 parts by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained. Note that the liquid plasticizer content also includes the amount of oil contained in the oil-applied rubber.

[0087] Examples of oils include process oils, vegetable oils, or mixtures thereof. Examples of process oils include paraffinic process oils, aromatic process oils, and naphthenic process oils. Examples of 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. Commercial products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kosan Co., Ltd., and Nisshin Oillio Group Ltd. can be used. Among these, process oils (paraffinic process oils, aromatic process oils, naphthenic process oils, etc.) and vegetable oils are preferred.

[0088] Examples of the above-mentioned resins (resins that are solid at room temperature (25°C)) that can be used in polymer compositions include the aforementioned aromatic vinyl polymers, coumarone indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, and acrylic resins that are solid at room temperature (25°C). In addition to the aforementioned aromatic vinyl polymers, coumarone indene resins, coumarone resins, indene resins, phenolic resins, rosin resins, petroleum resins, terpene resins, and acrylic resins that are solid at room temperature (25°C), modified polymers obtained by reacting such aromatic vinyl polymers with a phenylboronic acid compound represented by formula (1) can also be used. The above-mentioned resins may be hydrogenated. These resins may be used individually or in combination of two or more. Among them, aromatic vinyl polymers, petroleum resins, and terpene resins are preferred.

[0089] In the polymer composition, the resin content 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, per 100 parts by mass of the polymer component. The upper limit is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 90 parts by mass or less. Within the above range, better tire performance, such as wet grip performance, tends to be obtained.

[0090] Examples of plasticizers 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, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd.

[0091] The polymer composition preferably contains an anti-aging agent from the viewpoint of crack resistance, ozone resistance, etc.

[0092] While not particularly limited, the following are examples of anti-aging agents: naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging 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, and N,N′-di-2-naphthyl-p-phenylenediamine. Examples of anti-aging agents include p-phenylenediamine-based anti-aging agents such as amines; quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis, tris, and polyphenol-based anti-aging agents such as tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based anti-aging agents and quinoline-based anti-aging agents are preferred, and polymers of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercial products such as those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd. can be used.

[0093] In the polymer composition, the content of the anti-aging agent is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, per 100 parts by mass of the polymer component. The content is preferably 7.0 parts by mass or less, more preferably 4.0 parts by mass or less.

[0094] The polymer composition may contain stearic acid. In the polymer composition, the stearic acid content is preferably 0.5 to 10 parts by mass or more, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the polymer component.

[0095] In addition, conventionally known stearic acid can be used, such as products from NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Corporation, Chiba Fatty Acid Co., Ltd.

[0096] The polymer composition may also contain zinc oxide. In the polymer composition, the zinc oxide content is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of the polymer component.

[0097] In addition, conventionally known zinc oxides can be used, such as products from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., and Sakai Chemical Industry Co., Ltd.

[0098] The polymer composition may contain wax. In the polymer composition, the wax content is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of the polymer component.

[0099] The type of wax used is not particularly limited and includes petroleum-based waxes, natural waxes, and synthetic waxes obtained by refining or chemically processing multiple waxes. These waxes may be used individually or in combination of two or more types.

[0100] Examples of petroleum-based waxes include paraffin wax and microcrystalline wax. Examples of natural waxes are not limited to those derived from non-petroleum resources, and include plant-based waxes such as candelilla wax, carnauba wax, wood wax, rice wax, and jojoba wax; animal-based waxes such as beeswax, lanolin, and whale wax; mineral waxes such as ozokerite, ceresin, and petrolactam; and refined products thereof. Commercially available products include those from companies such as Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Chemical Co., Ltd.

[0101] The polymer composition may also contain sulfur. In the polymer composition, the sulfur content is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.7 parts by mass or more, per 100 parts by mass of the polymer component. The content is preferably 6.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.0 parts by mass or less.

[0102] Examples of sulfur commonly used in the rubber industry include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur. Commercially available products include those from Tsurumi Chemical Industries, Karuizawa Sulfur Co., Ltd., Shikoku Chemicals Co., Ltd., Flexis Co., Ltd., Nippon Dry Distillation Co., Ltd., and Hosoi Chemical Industry Co., Ltd. These can be used individually or in combination of two or more types.

[0103] The polymer composition may also contain a vulcanization accelerator. In the polymer composition, the content of the vulcanization accelerator is usually 0.3 to 10 parts by mass, preferably 0.5 to 7 parts by mass, per 100 parts by mass of the polymer component.

[0104] There are no particular restrictions on the type of vulcanization accelerator; commonly used ones can be used. Examples of vulcanization accelerators include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiadylsulfenamide; 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-benzothiazolesulfenamide, Nt-butyl-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, diortotrilguanidine, and orthotrilbiguanidine. These may be used individually or in combination of two or more. Among them, sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators are preferred.

[0105] In addition to the above-mentioned components, the polymer composition may also contain, as appropriate, conventional additives used in the application field, such as mold release agents and pigments.

[0106] As for the method of producing the polymer composition, known methods can be used. For example, it can be produced by kneading each component using a rubber kneading device such as an open roll or Banbury mixer, and crosslinking as necessary. The kneading conditions are that the kneading temperature is usually 50 to 200°C, preferably 80 to 190°C, and the kneading time is usually 30 seconds to 30 minutes, preferably 1 minute to 30 minutes.

[0107] The polymer composition can be used in tires, shoe soles, flooring materials, vibration dampers, seismic isolation materials, butyl frames, belts, hoses, gaskets, chemical plugs, and other rubber industrial products. In particular, it is preferable to use it as a polymer composition for tires because it exhibits excellent tire performance, such as wet grip performance.

[0108] The tire components to which the polymer composition is applied are not particularly limited, and include any tire components such as the cap tread, sidewall, base tread, bead apex, clinch apex, inner liner, under tread, breaker topping, and pry topping. In particular, it can be suitably applied to the cap tread due to its excellent wet grip performance.

[0109] <Tires> The polymer composition can be suitably used in tires. Examples of tires include pneumatic tires and non-pneumatic tires, but pneumatic tires are preferred. In particular, it can be suitably used in summer tires, winter tires (studless tires, snow tires, studded tires, etc.), all-season tires, etc. The tires can be used in passenger car tires, large passenger car tires, large SUV tires, heavy-duty tires for trucks and buses, light truck tires, motorcycle tires, racing tires (high-performance tires), etc. In particular, it can be suitably used in passenger car tires and light truck tires.

[0110] The tire is manufactured using the polymer composition by conventional methods. For example, a polymer composition containing various materials can be extruded to match the shape of a tire component at an unvulcanized stage, and then molded together with other tire components on a tire molding machine in a conventional manner to form an unvulcanized tire. After that, the tire can be manufactured by heating and pressurizing it in a vulcanizing machine. [Examples]

[0111] The present disclosure will be described in detail based on examples, but the present disclosure is not limited to these examples.

[0112] <Synthesis of phenylboronic acid compounds> Phenylboronic acid compound C (represented by formula (1)) was synthesized using the synthetic route shown in Figure 1. Specifically, it was synthesized using the following method.

[0113] Phenylboronic acid compound B and an amine compound were reacted overnight at room temperature in methanol, reduced with sodium borohydride (NaBH4), and deprotected with hydrochloric acid (HCl) to form phenylboronic acid compound C.

[0114] The composite shown in Figure 2 1 From the 1H-NMR spectrum, it was found that phenylboronic acid compound C (a phenylboronic acid compound represented by formula (1)) was synthesized.

[0115] <Synthesis of Modified Polymers> Modified polymers A to D (modified polymers modified with phenylboronic acid compounds represented by formula (1)) are synthesized using the synthesis route shown in Figure 3. Specifically, it is synthesized using the following method.

[0116] (Synthesis of modified polymer A) Add a stirring bar, ENR25, and THF to a three-necked flask and stir until dissolved. Add phenylboronic acid compound A and react at 70°C for 24 hours, then precipitate with methanol. Air dry in a fume hood and dry at 70°C to obtain modified polymer A.

[0117] (Synthesis of modified polymer B) Add a stirring bar, ENR25, and THF to a three-necked flask and stir until dissolved. Add phenylboronic acid compound C and react at 70°C for 24 hours, then precipitate with methanol. Air dry in a fume hood and dry at 70°C to obtain modified polymer B.

[0118] (Synthesis of modified polymer C) Phenylboronic acid compound C and DMTMM are dissolved separately in water in beakers and added to carboxylic acid-modified SBR latex. The mixture is stirred at room temperature for 48 hours, and then solidified with a 1% sulfuric acid aqueous solution. The solid is dried to obtain modified polymer C.

[0119] (Synthesis of modified polymer D) Liquid polyisoprene modified with carboxyl groups and phenylboronic acid compound C were added to chloroform, and a dehydration condensation reaction was carried out using EDC / HOBt to obtain modified polymer D. Modified polymer D was purified by washing with methanol.

[0120] The following materials were used in the synthesis of phenylboronic acid compound B and modified polymers A-D shown in Figures 1 and 3. Phenylboronic acid compound B: Manufactured by Boron Molecular Pty Limited (Compound B in Figure 1) Amine compound: Combi-Blocks (Amine compound shown in Figure 1) Phenylboronic acid compound A: Manufactured by Combi-Blocks (Compound A in Figure 3) Sodium borohydride (NaBH4): Manufactured by Fujifilm Wako Pure Chemical Corporation Hydrochloric acid (HCl): Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. ENR: ENR25 (epoxidation rate 25% by mass) manufactured by GUTHRIE POLYMER SDN BHD. Carboxylic acid-modified SBR: Carboxylic acid-modified SBR latex manufactured by Asahi Kasei Corporation, JSR, and Nippon A&L. Liquid polyisoprene modified with carboxyl groups (LIR-410, manufactured by Kuraray Co., Ltd., molecular weight 30,000, 10 carboxyl groups per molecule, glass transition temperature -59°C) EDC: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (manufactured by TCI) HOBt: 1-hydroxybenzotriazole (manufactured by TCI)

[0121] The IR spectrum shown in Figure 4, 1 From the 1H-NMR spectrum, it was found that phenylboronic acid compound C (phenylboronic acid compound represented by formula (1)), liquid polyisoprene modified with a carboxyl group, and liquid polyisoprene modified with phenylboronic acid compound C (modified polymer D) were synthesized.

[0122] Furthermore, it is believed that modified polymers A to C (modified polymers modified with phenylboronic acid compounds represented by formula (1)) have been synthesized.

[0123] As described above, it has been found that the phenylboronic acid compound represented by formula (1) can be synthesized, and it is also considered possible to synthesize polymers modified with the phenylboronic acid compound represented by formula (1).

[0124] When the obtained modified polymers A to D are dried at room temperature and pressure until a constant weight is reached, and then repeatedly immersed in water to wet them, they undergo reversible dehydration condensation of three molecules, generating boroxine (boroxine crosslinks). Subsequently, when exposed to water, the generated boroxine crosslinks are thought to decompose. Therefore, it is considered that modified polymers A to D possess the function of reversibly changing their physical properties in response to water.

[0125] In particular, modified polymer D became a transparent, non-fluid gel, confirming that crosslinking had progressed. Furthermore, the elastomer obtained by removing the solvent from this gel could be molded at 100°C, suggesting that the crosslinking was thermally reversible.

[0126] Furthermore, when a modified polymer with such reversible property changes due to water is used in a tire rubber composition, it is thought that when it comes into contact with a wet road surface, the elastic modulus decreases, increasing the contact area with the road surface during driving on a wet surface, which increases friction and improves loss, thus improving wet grip performance.

[0127] Furthermore, the phenylboronic acid compound represented by formula (1) is considered to be highly reactive and capable of reacting with various polymers, making it possible to provide polymers modified with various phenylboronic acid compounds represented by formula (1).

[0128] Disclosure (1) is a phenylboronic acid compound represented by the following formula (1-1). [ka] (R 21 and R 22 R is a divalent hydrocarbon group which may have substituents, either identical or different, and may contain heteroatoms. 23 ~R 25 m is a monovalent hydrocarbon group that may have a hydrogen atom or substituents, and may also contain a heteroatom. m is an integer from 1 to 5.

[0129] Disclosure (2) is a modified polymer modified with a phenylboronic acid compound represented by the following formula (1). [ka] (R 11 (where n is an integer from 1 to 5.)

[0130] Disclosure (3) is the modified polymer according to Disclosure (2), wherein the polymer constituting the backbone of the modified polymer is at least one selected from the group consisting of isoprene rubber, acrylonitrile butadiene rubber, butadiene rubber, and styrene butadiene rubber.

[0131] Disclosure (4) is a modified polymer according to Disclosure (2) or (3) that is in a solid state at 25°C and has a weight-average molecular weight of 10,000 or more.

[0132] Disclosure (5) is the modified polymer described in Disclosure (2) which is in a liquid state at 25°C.

[0133] Disclosure (6) is a polymer composition comprising a modified polymer as described in any of Disclosures (2) to (5).

[0134] This disclosure (7) contains a rubber component, The polymer composition according to disclosure (6) comprises a modified polymer in which the rubber component is modified with a phenylboronic acid compound represented by formula (1) which is in a solid state at 25°C.

[0135] This disclosure (8) includes a liquid polymer, The polymer composition according to this disclosure (6) comprises a modified polymer that has been modified with a phenylboronic acid compound represented by formula (1), which is in a liquid state at 25°C.

[0136] Disclosure (9) relates to a tire having a tire member composed of a polymer composition as described in any of Disclosures (6) to (8).

Claims

1. A tire having a tire component made of a polymer composition containing a modified polymer modified with a phenylboronic acid compound represented by the following formula (1). 【Chemistry 1】 (R １１ (where n is an integer from 1 to 5.)

2. The tire according to claim 1, wherein the polymer constituting the backbone of the modified polymer is at least one selected from the group consisting of isoprene rubber, acrylonitrile butadiene rubber, butadiene rubber, and styrene butadiene rubber.

3. The tire according to claim 1 or 2, wherein the modified polymer is in a solid state at 25°C and has a weight-average molecular weight of 10,000 or more.

4. The tire according to claim 1, wherein the modified polymer is in a liquid state at 25°C.

5. The polymer composition contains a rubber component, The tire according to claim 1, wherein the rubber component comprises a modified polymer modified with a phenylboronic acid compound represented by formula (1), which is in a solid state at 25°C.

6. Certain polymer compositions include liquid polymers, The tire according to claim 1, wherein the liquid polymer comprises a modified polymer modified with a phenylboronic acid compound represented by formula (1), which is in a liquid state at 25°C.

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