Rubber composition and tire

Abstract

The present invention addresses the problem of providing a rubber composition capable of improving the low-loss characteristics and steering stability of tires. The rubber composition comprises a rubber component, a hydrogenated resin, and a filler, and is characterized in that the rubber component comprises a modified conjugated-diene-based polymer which is a product of reaction between a conjugated-diene-based polymer having an active terminal and a compound [M] having, in total, two or more groups selected from among -CR1=N-A1 groups and -N=CR1-A1 groups (R1 is a hydrogen atom or a hydrocarbyl group and A1 is a monovalent group having an alkoxysilyl group), the hydrogenated resin has a softening point higher than 110°C and a weight-average molecular weight of 200-1200 g / mol in terms of polystyrene, and the filler comprises silica.

Description

[Technical Field]

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

[0002] In recent years, with the rise in environmental awareness and the trend toward global carbon dioxide emission regulations, there has been an increasing demand for improved fuel efficiency in automobiles. To meet these demands, there is also a demand for reduced rolling resistance in tires. To address this demand, a common method for reducing tire rolling resistance has been to use rubber compositions with low loss tangents (tan δ) (hereinafter referred to as "excellent low loss properties"). To improve the low loss properties of rubber compositions, various techniques have been used, such as incorporating modified polymers, modified fillers, and dispersion improvers. For example, Patent Document 1 below discloses a method for producing a polymer having a conjugated diene base polymer with an active terminal and a group "-CR 1 =NA 1 " and the group "-N=CR 1 -A 1 " (However, R 1 is a hydrogen atom or a hydrocarbyl group, and A 1 is a monovalent group having an alkoxysilyl group.) and a compound [M] having a total of two or more groups selected from the group consisting of:

[0003] Furthermore, from the standpoint of improving vehicle safety, it is also important to ensure the steering stability of tires, and there is a demand for improving the steering stability as well as the fuel economy performance of tires. In response to this, Patent Document 2 below discloses a rubber composition comprising a rubber component (A) containing a natural rubber (A1) and a modified diene rubber (A2) having a glass transition temperature (Tg) of −50° C. or lower, and a thermoplastic resin (B), the rubber composition having a storage modulus of 4.5 MPa or higher at 1% strain at 30° C. and a storage modulus of 16.7 MPa or lower at 4% strain at 0° C.; and by applying this rubber composition to a tire, it is possible to reduce the rolling resistance of the tire while improving handling stability and wet performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 221943 [Patent Document 2] International Publication No. 2018 / 056382 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inventors of the present invention have conducted studies and found that the rubber composition disclosed in Patent Document 1 does not have sufficient low loss properties, and that tires using this rubber composition have room for improvement in terms of handling stability. Furthermore, it has also been found that tires using the rubber composition disclosed in Patent Document 2 need to have further reduced rolling resistance and improved handling stability.

[0006] Therefore, an object of the present invention is to provide a rubber composition that can solve the above-mentioned problems of the conventional technology and can improve the low loss property and steering stability of a tire. Another object of the present invention is to provide a tire that has low loss properties and excellent steering stability. [Means for solving the problem]

[0007] The gist and configuration of the present invention to solve the above problems is as follows.

[0008] The rubber composition of the present invention is a rubber composition including a rubber component, a hydrogenated resin, and a filler, The rubber component comprises a conjugated diene polymer having an active terminal and a group "-CR 1 =NA 1 " and the group "-N=CR 1 -A 1 " (However, R 1 is a hydrogen atom or a hydrocarbyl group, and A 1 is a monovalent group having an alkoxysilyl group; and a compound [M] having a total of two or more groups selected from The hydrogenated resin has a softening point higher than 110°C and a weight average molecular weight in terms of polystyrene of 200 to 1200 g / mol, The filler comprises silica. It is characterized by:

[0009] The tire of the present invention is characterized by including the above rubber composition. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a rubber composition that can improve the low loss property and steering stability of a tire. Furthermore, according to the present invention, a tire having low loss properties and excellent steering stability can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0011] The rubber composition and tire of the present invention will be described in detail below by way of example based on embodiments thereof.

[0012] <Rubber composition> The rubber composition of the present invention includes a rubber component, a hydrogenated resin, and a filler. The rubber composition of the present invention further includes: (1) the rubber component contains a conjugated diene polymer having an active end and a group "-CR 1 =NA 1 " and the group "-N=CR 1 -A 1" (However, R 1 is a hydrogen atom or a hydrocarbyl group, and A 1 is a monovalent group having an alkoxysilyl group.) and a compound [M] having a total of two or more groups selected from the group consisting of (1) and (2), (2) the hydrogenated resin has a softening point of more than 110°C and a weight average molecular weight of 200 to 1200 g / mol in terms of polystyrene, and (3) the filler contains silica.

[0013] In the rubber composition of the present invention, the modified conjugated diene polymer improves the dispersibility of the filler containing silica, thereby reducing the hysteresis loss and improving the low loss property. Furthermore, in the rubber composition of the present invention, the hydrogenated resin is easily compatible with the rubber component and improves the hardness (elastic modulus) of the rubber composition, and therefore, when applied to a tire, the steering stability of the tire can be improved. Furthermore, in the rubber composition of the present invention, by combining the modified conjugated diene polymer with the hydrogenated resin, a synergistic effect can be obtained in improving the low loss property and the handling stability. Therefore, by applying the rubber composition of the present invention to a tire, the tire's low loss property and handling stability can be significantly improved.

[0014] (rubber component) The rubber component of the rubber composition of the present embodiment comprises a conjugated diene polymer having an active terminal and a group "-CR 1 =NA 1 " and the group "-N=CR 1 -A 1 " (However, R 1 is a hydrogen atom or a hydrocarbyl group, and A 1 is a monovalent group having an alkoxysilyl group.) and a compound [M] having a total of two or more groups selected from the group consisting of: The inclusion of the modified conjugated diene polymer in the rubber component improves the dispersibility of the filler containing silica, thereby improving the low loss properties of the rubber composition. Furthermore, the modified conjugated diene polymer, when combined with a hydrogenated resin described below, can significantly improve the low loss properties and handling stability of a tire using the rubber composition.

[0015] --Modified conjugated diene polymer-- The modified conjugated diene polymer comprises a conjugated diene polymer having an active terminal and a group "-CR 1 =NA 1 " and the group "-N=CR 1 -A 1 " (However, R 1 is a hydrogen atom or a hydrocarbyl group, and A 1 is a monovalent group having an alkoxysilyl group.) and a compound [M] having a total of two or more groups selected from the group consisting of

[0016] The conjugated diene polymer having an active terminal can be obtained by polymerizing a monomer containing a conjugated diene compound. Examples of the conjugated diene compound used in the polymerization include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2-phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, and 2-chloro-1,3-butadiene. Among these compounds, 1,3-butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene are preferred, and 1,3-butadiene is particularly preferred.

[0017] The conjugated diene polymer may be a homopolymer of a conjugated diene compound, or a copolymer of a conjugated diene compound and another monomer. From the viewpoint of increasing the hardness (elastic modulus) of the rubber composition, the conjugated diene polymer is preferably a copolymer of a conjugated diene compound and an aromatic vinyl compound. Examples of aromatic vinyl compounds used in the polymerization include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, t-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, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylene (e.g., 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene). Among these, styrene and α-methylstyrene are preferred as aromatic vinyl compounds, and styrene is particularly preferred.

[0018] Furthermore, when the conjugated diene polymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound, it is preferably a copolymer containing 1,3-butadiene and styrene in the monomer composition, because it has high living properties in anionic polymerization. Furthermore, the copolymer preferably has a random copolymerization portion in which the distribution of the conjugated diene compound and the aromatic vinyl compound is irregular, and may further have a block portion made of the conjugated diene compound or the aromatic vinyl compound.

[0019] When the conjugated diene polymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound, the proportion of aromatic vinyl units in the conjugated diene polymer is preferably less than 10% by mass. When the proportion of aromatic vinyl units is less than 10% by mass, the low loss properties of the tire can be further improved when the tire is applied to the tire.

[0020] In the polymerization, compounds other than conjugated diene compounds and aromatic vinyl compounds (hereinafter also referred to as "other monomers") may be used as monomers. Examples of other monomers include acrylonitrile, methyl (meth)acrylate, and ethyl (meth)acrylate. The proportion of other monomers used is preferably 10% by mass or less, and more preferably 5% by mass or less, of the total amount of monomers used in the polymerization.

[0021] The polymerization method for obtaining the conjugated diene polymer may be, for example, a solution polymerization method, a gas phase polymerization method, or a bulk polymerization method, with the solution polymerization method being particularly preferred. The polymerization method may be either a batch method or a continuous method. When using the solution polymerization method, a specific example of the polymerization method is a method in which a monomer containing a conjugated diene compound is polymerized in an organic solvent in the presence of a polymerization initiator and, if necessary, a randomizer.

[0022] As the polymerization initiator used in the polymerization, it is preferable to use at least one of an alkali metal compound and an alkaline earth metal compound.Specific examples of the polymerization initiator include alkyllithium such as methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, and t-butyllithium, 1,4-dilithiobutane, phenyllithium, stilbenelithium, naphthyllithium, 1,3-bis(1-lithio-1,3-dimethylpentyl)benzene, 1,3-phenylenebis(3-methyl-1-phenylpentylidene)dilithium, naphthylsodium, naphthylpotassium, di-n-butylmagnesium, di-n-hexylmagnesium, ethoxypotassium, and calcium stearate.Among these, lithium compounds are preferred, and alkyllithium is more preferred. The total amount of the polymerization initiator used is preferably 0.2 to 20 mmol per 100 g of the monomer used in the polymerization.

[0023] The polymerization reaction may be carried out using, as a polymerization initiator, a mixture of at least one of an alkali metal compound and an alkaline earth metal compound and a compound having a functional group that interacts with silica. By carrying out the polymerization in the presence of the mixture, the polymerization initiation terminal of the conjugated diene polymer can be modified with the functional group that interacts with silica. In this specification, "functional groups that interact with silica" refers to groups having elements that interact with silica, such as nitrogen, sulfur, phosphorus, oxygen, etc. "Interaction" refers to the formation of a covalent bond between molecules or an intermolecular force that is weaker than a covalent bond (for example, an electromagnetic force acting between molecules such as an ion-dipole interaction, a dipole-dipole interaction, a hydrogen bond, or a van der Waals force).

[0024] The compound having a functional group that interacts with silica and used for modifying the polymerization initiation terminal is preferably a nitrogen-containing compound such as a secondary amine compound.Specific examples of the nitrogen-containing compound include dimethylamine, diethylamine, dipropylamine, dibutylamine, dodecamethyleneimine, N,N'-dimethyl-N'-trimethylsilyl-1,6-diaminohexane, piperidine, pyrrolidine, hexamethyleneimine, heptamethyleneimine, dicyclohexylamine, N-methylbenzylamine, di-(2-ethylhexyl)amine, diallylamine, morpholine, N-(trimethylsilyl)piperazine, N-(tert-butyldimethylsilyl)piperazine, and 1,3-ditrimethylsilyl-1,3,5-triazinane.

[0025] When polymerization is carried out in the presence of the mixture, at least one of an alkali metal compound and an alkaline earth metal compound and a compound having a functional group that interacts with silica may be mixed in advance, and the mixture may be added to the polymerization system to carry out polymerization. Alternatively, at least one of an alkali metal compound and an alkaline earth metal compound and a compound having a functional group that interacts with silica may be added to the polymerization system, and the two may be mixed in the polymerization system to carry out polymerization. Either of these cases is included in the embodiment of "polymerizing a monomer containing a conjugated diene compound in the presence of an initiator containing at least one of an alkali metal compound and an alkaline earth metal compound."

[0026] The randomizer can be used for the purpose of adjusting the vinyl bond content, which represents the content of vinyl bonds in a polymer. Examples of randomizers include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(tetrahydrofuryl)propane, 2-(2-ethoxyethoxy)-2-methylpropane, triethylamine, pyridine, N-methylmorpholine, and tetramethylethylenediamine. These can be used alone or in combination of two or more.

[0027] The organic solvent used in the polymerization may be any organic solvent inert to the reaction, and examples thereof include aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. Among these, hydrocarbons having 3 to 8 carbon atoms are preferred, and specific examples thereof include propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans-2-butene, cis-2-butene, 1-pentyne, 2-pentyne, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, heptane, cyclopentane, methylcyclopentane, methylcyclohexane, 1-pentene, 2-pentene, and cyclohexene. The organic solvent may be used alone or in combination of two or more.

[0028] When solution polymerization is performed, the monomer concentration in the reaction solvent is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, from the viewpoint of maintaining a balance between productivity and ease of polymerization control. The temperature of the polymerization reaction is preferably -20°C to 150°C, more preferably 0°C to 120°C. The polymerization reaction is preferably carried out under a pressure sufficient to maintain the monomers substantially in a liquid phase. Such a pressure can be obtained by, for example, pressurizing the inside of a reactor with a gas inert to the polymerization reaction.

[0029] The conjugated diene polymer preferably has a weight average molecular weight (Mw) of 5.0×10 in terms of polystyrene as determined by gel permeation chromatography (GPC). 4 ~2.0×10 6 Mw is 5.0×10 4 When the crosslinked polymer is 2.0×10 or more, the tensile strength, low heat buildup and abrasion resistance of the crosslinked polymer tend to be easily improved. 6 When the modified polymer is used, the rubber composition obtained using the modified polymer tends to have good processability. 5 ~1.0×10 6 is.

[0030] In the conjugated diene polymer having an active terminal, the vinyl bond content in the conjugated diene unit (e.g., butadiene unit) is preferably 10 to 70 mass %, more preferably 20 to 60 mass %. When the vinyl bond content is 10 mass % or more, the grip property tends to be improved, and when it is 70 mass % or less, the abrasion resistance of the obtained vulcanized rubber tends to be improved. In this specification, the "vinyl bond content" is a value indicating the content ratio of structural units having 1,2-bonds to all structural units of the conjugated diene compound (e.g., butadiene) in the conjugated diene polymer, 1 The values ​​were measured by H-NMR.

[0031] The modified conjugated diene polymer is obtained by converting the above-mentioned conjugated diene polymer into a compound having a group "-CR1 =NA 1 " and the group "-N=CR 1 -A 1 " (However, R 1 is a hydrogen atom or a hydrocarbyl group, and A 1 is a monovalent group having an alkoxysilyl group.) with a compound [M] having a total of two or more specific imino groups. By using a compound having a total of two or more of the specific imino groups as a modifying agent, a modified conjugated diene polymer having a large number of branches in the polymer chain and modified with a group that interacts with a filler such as silica can be obtained through the modification process.

[0032] In the specific imino group, R 1 Examples of the hydrocarbyl group include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. 1 The structure of R is not particularly limited as long as it has an alkoxysilyl group, but it is preferably a group further having a methylene group or a polymethylene group, and more preferably has a methylene group or a polymethylene group and an alkoxysilyl group, and the methylene group or the polymethylene group is bonded to a nitrogen atom or a carbon atom constituting a carbon-nitrogen double bond. The number of specific imino groups possessed by compound [M] may be 2 or more, preferably 2 to 6. In addition, the number of R possessed by compound [M] may be 2 or more, and preferably 2 to 6. 1 , A 1 may be the same or different.

[0033] The compound [M] is preferably a compound represented by the following general formula (1). [ka] [In formula (1), R 2 and R 3 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, and R 4 is an alkanediyl group having 1 to 20 carbon atoms, and A 2 is the group *-C(R1 )=N-" or the group "*-N=C(R 1 )-" (However, R 1 is a hydrogen atom or a hydrocarbyl group, and "*" is R 5 ) indicates that the bond is bonded to R. 5 is an m-valent hydrocarbyl group having 1 to 20 carbon atoms, or an m-valent group having 1 to 20 carbon atoms and having at least one atom selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms and having no active hydrogen. n is an integer of 1 to 3, and m is an integer of 2 to 10. In the formula, multiple R 2 , R 3 , R 4 , A 2 , n may be the same or different.]

[0034] In the above formula (1), R 2 , R 3 Examples of the hydrocarbyl group include an alkyl group having 1 to 20 carbon atoms, an allyl group, a cycloalkyl group having 3 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. 4 The alkanediyl group (alkylene group) having 1 to 20 carbon atoms is preferably linear.

[0035] A 2 R has 1 The above explanation applies to n. n is preferably 2 or 3, and more preferably 3, in that the effect of improving silica dispersibility is high. R 5 Examples of the m-valent hydrocarbyl group include groups in which m hydrogen atoms have been removed from a chain hydrocarbon having 1 to 20 carbon atoms, an alicyclic hydrocarbon having 3 to 20 carbon atoms, or an aromatic hydrocarbon having 6 to 20 carbon atoms. In view of the high effect of improving the abrasion resistance of the resulting vulcanized rubber, a group in which m hydrogen atoms have been removed from the ring portion of an aromatic hydrocarbon (aromatic ring group) is preferred. Specific examples of such aromatic hydrocarbons include a ring structure represented by the following general formula (2) and a polycyclic structure formed by linking two or more such ring structures (for example, a biphenyl group). [ka] [In formula (2), r is an integer of 0 to 5.]

[0036] R 5 When is an m-valent group having 1 to 20 carbon atoms and having at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom and having no active hydrogen, preferred specific examples include an m-valent heterocyclic group, an m-valent group having a tertiary amine structure, etc. The heterocyclic group is preferably a conjugated system, and examples thereof include a group in which m hydrogen atoms have been removed from a ring portion of a single ring or fused ring such as pyridine, pyrimidine, pyrazine, quinoline, naphthalidine, furan, or thiophene, or a structure in which a plurality of such single rings or fused rings are linked together. m is an integer of 2 to 10. From the viewpoint of processability of the rubber composition, m is preferably 2 to 6. In this specification, "active hydrogen" refers to a hydrogen atom bonded to an atom other than a carbon atom, and preferably refers to one having a bond energy lower than that of the carbon-hydrogen bond of polymethylene.

[0037] Specific examples of the compound [M] include compounds represented by the following formulae (M-1) to (M-23). ​​The compound [M] may be used singly or in combination of two or more. 7 represents a hydrogen atom or an alkyl group. [ka] [ka] [ka] [ka]

[0038] The compound [M] can be synthesized by appropriately combining conventional methods in organic chemistry. For example, one example of a method for obtaining the compound represented by the formula (1) is to: (i) combine an alkoxysilyl group and R4 a monofunctional amine compound having R 5 (ii) a method of dehydrating and condensing a polyfunctional aldehyde compound having the formula (e.g., terephthalaldehyde, isophthalaldehyde, phthaldialdehyde, 2,4-pyridinedicarboxaldehyde, etc.) having R 5 and a polyfunctional amine compound (e.g., tris(2-aminoethyl)amine, N,N'-bis(2-aminoethyl)methylamine, etc.) having an alkoxysilyl group and R 4 and a method of dehydrating and condensing a monofunctional hydroxyl group-containing compound having the formula (e.g., 4-(triethoxysilyl)butanal). These synthesis reactions are preferably carried out in an appropriate organic solvent, and, if necessary, in the presence of an appropriate catalyst. However, the synthesis method of compound [M] is not limited to the above-mentioned methods.

[0039] The reaction between the conjugated diene polymer having an active terminal and the compound [M] can be carried out, for example, as a solution reaction. The proportion of the compound [M] (when two or more types are used, the total amount) used is preferably 0.01 moles or more, more preferably 0.05 moles or more, per mole of the metal atom involved in the polymerization of the polymerization initiator, from the viewpoint of sufficiently progressing the modification reaction. Furthermore, the upper limit is preferably less than 2.0 moles, more preferably less than 1.5 moles, per mole of the metal atom involved in the polymerization of the polymerization initiator, in order to avoid excessive addition.

[0040] The temperature of the modification reaction is usually the same as that of the polymerization reaction, and is preferably -20°C to 150°C, and more preferably 0°C to 120°C. If the reaction temperature is low, the viscosity of the polymer after modification tends to increase, while if the reaction temperature is high, the active polymerization terminals are likely to be deactivated. The reaction time is preferably 1 minute to 5 hours, and more preferably 2 minutes to 1 hour.

[0041] When reacting the conjugated diene polymer having an active terminal with the compound [M], another modifier or coupling agent may be used together with the compound [M]. The other modifier or coupling agent is not particularly limited as long as it is a compound capable of reacting with the active terminal of the conjugated diene polymer obtained by the polymerization, and compounds known as modifiers or coupling agents for conjugated diene polymers can be used. When another modifier or coupling agent is used, its proportion is preferably 10 mol % or less, more preferably 5 mol % or less.

[0042] The modified conjugated diene polymer contained in the reaction solution can be isolated by, for example, a known desolvation method such as steam stripping and a drying procedure such as heat treatment. The weight average molecular weight of the modified conjugated diene polymer, as determined by GPC in terms of polystyrene, is preferably 1.0 × 10, from the viewpoint of simultaneously obtaining a modified conjugated diene polymer having a sufficiently high Mooney viscosity and good shape stability, and obtaining a rubber composition having excellent processability. 5 ~4.0×10 6 More preferably, it is 1.8 × 10 5 ~3.0×10 6 and more preferably 2.0 × 10 5 ~2.0×10 6 The weight average molecular weight of the modified conjugated diene polymer is a value determined from the maximum peak molecular weight of the GPC curve measured by GPC after the reaction of the conjugated diene polymer having an active terminal with the compound [M].

[0043] The modified conjugated diene polymer has a branched structure in which modified or unmodified conjugated diene polymer chains are bonded to a plurality of reaction points (carbon-nitrogen double bonds (C═N groups), alkoxysilyl groups) of the compound [M]. From the viewpoint of achieving a sufficiently high Mooney viscosity and good cold flow of the resulting modified conjugated diene polymer, the number of branches in the polymer chain per molecule of the modified conjugated diene polymer is preferably 3 or more, more preferably in the range of 3 to 20. Note that, since a C═N group is more reactive than an alkoxysilyl group and reacts preferentially with the active terminal of the conjugated diene polymer, the number of remaining alkoxysilyl groups increases, improving the interaction between the resulting modified conjugated diene polymer and silica, which is thought to result in excellent low loss properties.

[0044] The modified conjugated diene polymer is preferably represented by the following general formula (3). [ka] [In formula (3), R 2 is a hydrocarbyl group having 1 to 20 carbon atoms, and R 6 is a hydrocarbyloxy group having 1 to 20 carbon atoms or a modified or unmodified conjugated diene polymer chain, and R 4 is an alkanediyl group having 1 to 20 carbon atoms, and Z is a group represented by the following general formula (4) or (5): 5 is an m-valent hydrocarbyl group having 1 to 20 carbon atoms, or an m-valent group having 1 to 20 carbon atoms and having at least one atom selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms and having no active hydrogen, where n is an integer of 1 to 3, and m is an integer of 2 to 10. In the formula, multiple R 2 , R 4 , R 6 , Z, and n may be the same or different.] [ka] [In formulas (4) and (5), R 1 is a hydrogen atom or a hydrocarbyl group, and Poly is a modified or unmodified conjugated diene polymer chain. 5 indicates a bond that bonds to .] The modified conjugated diene polymer represented by the general formula (3) has a significant effect of improving the dispersibility of fillers including silica, and further improves the low loss properties of the rubber composition. Furthermore, when the rubber composition is applied to a tire, the low loss properties of the tire are further improved.

[0045] In the above general formulas (3), (4) and (5), R 1 , R 2 , R 4 and R 5 The same applies to the general formula (1). 6 The hydrocarbyloxy group in R is preferably an ethoxy group or a methoxy group. 6 The conjugated diene polymer chain in formula (1) and the conjugated diene polymer chain Poly in formulas (4) and (5) have a structure corresponding to the conjugated diene polymer having an active end obtained in the polymerization step. These conjugated diene polymer chains may have a functional group at the end that interacts with silica.

[0046] In the rubber composition of this embodiment, the modified conjugated diene polymer preferably has aromatic vinyl units and conjugated diene units, and the proportion of the aromatic vinyl units in the modified conjugated diene polymer is 10% by mass or less. When the modified conjugated diene polymer has aromatic vinyl units and conjugated diene units, and the proportion of the aromatic vinyl units is 10% by mass or less, the low loss properties of the tire can be further improved when the rubber composition is applied to a tire.

[0047] In the rubber composition of this embodiment, the modified conjugated diene polymer preferably has a vinyl bond content in the conjugated diene units (e.g., butadiene units) of 10 to 70 mass%, more preferably 20 to 60 mass%. When the vinyl bond content is 10 mass% or more, the grip properties tend to be improved, and when it is 70 mass% or less, the abrasion resistance of the resulting vulcanized rubber tends to be improved.

[0048] In the rubber composition of the present embodiment, the modified conjugated diene polymer has a peak top molecular weight (Mp) of 1.0 × 10 6It is preferable that the peak top molecular weight (Mp) of the modified conjugated diene polymer is less than 1.0 × 10 6 When the peak top molecular weight (Mp) of the modified conjugated diene polymer is less than 50×10, the rubber composition tends to have good processability. 3 The peak top molecular weight (Mp) is a value calculated in terms of polystyrene from the retention time corresponding to the apex of the maximum peak in a GPC curve obtained by gel permeation chromatography (GPC).

[0049] From the viewpoint of low loss properties, the proportion of the modified conjugated diene polymer in the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and may be 100% by mass, but is preferably 60% by mass or less, more preferably 50% by mass or less.

[0050] --Other rubber components-- Examples of rubber components other than the modified conjugated diene polymer include natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), butyl rubber (IIR), halogenated butyl rubber, and ethylene-propylene rubber (EPR, EPDM). The proportion of the other rubber component in the rubber component is preferably 95% by mass or less, more preferably 90% by mass or less, and is preferably 40% by mass or more, more preferably 50% by mass or more.

[0051] (hydrogenated resin) The rubber composition of the present embodiment contains a hydrogenated resin, and the hydrogenated resin has a softening point higher than 110° C. and a weight average molecular weight in terms of polystyrene of 200 to 1200 g / mol.

[0052] If the softening point of the hydrogenated resin is 110°C or lower, the low loss properties and handling stability of the tire cannot be sufficiently improved. From the viewpoint of further improving the low loss properties and handling stability of the tire, the softening point of the hydrogenated resin is preferably 115°C or higher, more preferably 118°C or higher, even more preferably 121°C or higher, even more preferably 123°C or higher, even more preferably 125°C or higher, even more preferably 127°C or higher, even more preferably 128°C or higher, and even more preferably 129°C or higher. Furthermore, from the viewpoint of further improving the low loss properties and handling stability of the tire, the softening point of the hydrogenated resin is preferably 145°C or lower, preferably 143°C or lower, and more preferably 140°C or lower.

[0053] Furthermore, if the weight average molecular weight of the hydrogenated resin in terms of polystyrene is less than 200 g / mol, the hydrogenated resin will precipitate from the tire, preventing the effects of the hydrogenated resin from being fully exerted. On the other hand, if the weight average molecular weight exceeds 1200 g / mol, the hydrogenated resin will not be compatible with the rubber component. From the viewpoint of suppressing precipitation of the hydrogenated resin from the tire and suppressing deterioration of the tire appearance, the weight average molecular weight of the hydrogenated resin in terms of polystyrene is preferably 300 g / mol or more, preferably 500 g / mol or more, more preferably 700 g / mol or more, and even more preferably 750 g / mol or more. Furthermore, from the viewpoint of increasing the compatibility of the hydrogenated resin with the rubber component and further enhancing the effects of the hydrogenated resin, the weight average molecular weight of the hydrogenated resin in terms of polystyrene is preferably 1150 g / mol or less, more preferably 1100 g / mol or less, and even more preferably 1050 g / mol or less.

[0054] The hydrogenated resin means a resin obtained by reducing and hydrogenating a resin. Examples of resins that can be used as raw materials for hydrogenated resins include C5 resins, C5-C9 resins, C9 resins, terpene resins, dicyclopentadiene resins, and terpene-aromatic compound resins. These resins may be used alone or in combination of two or more.

[0055] Examples of the C5 resin include aliphatic petroleum resins obtained by (co)polymerizing C5 fractions obtained by thermal cracking of naphtha in the petrochemical industry. The C5 fraction typically contains olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene, and diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene. Commercially available C5 resins can be used.

[0056] The C5-C9 resin refers to a C5-C9 synthetic petroleum resin, and examples of the C5-C9 resin include petroleum-derived C5-C 11 Examples of such solid polymers include those obtained by polymerizing the fraction using a Friedel-Crafts catalyst such as AlCl3 or BF3, and more specifically, copolymers containing styrene, vinyltoluene, α-methylstyrene, indene, etc. as the main component. As the C5-C9 resin, a resin with a low content of C9 or higher components is preferred from the viewpoint of compatibility with the rubber component. Here, "low content of C9 or higher components" means that the content of C9 or higher components in the total amount of resin is less than 50 mass%, preferably 40 mass% or less. Commercially available C5-C9 resins can be used.

[0057] The C9 resin refers to a C9 synthetic petroleum resin, for example, a solid polymer obtained by polymerizing a C9 fraction using a Friedel-Crafts catalyst such as AlCl3 or BF3. Examples of C9 resins include copolymers containing indene, α-methylstyrene, vinyltoluene, and the like as main components.

[0058] The terpene resin is a solid resin obtained by blending turpentine, which is obtained simultaneously with the extraction of rosin from pine trees, or a polymerization component separated from the blend, and polymerizing the blend using a Friedel-Crafts catalyst. Examples of such resins include β-pinene resin and α-pinene resin. A representative example of a terpene-aromatic compound resin is terpene-phenol resin. This terpene-phenol resin can be obtained by reacting terpenes with various phenols using a Friedel-Crafts catalyst, or by further condensing the terpene with formalin. There are no particular limitations on the terpenes used as raw materials; monoterpene hydrocarbons such as α-pinene and limonene are preferred, with those containing α-pinene being more preferred, and α-pinene being particularly preferred.

[0059] The dicyclopentadiene resin refers to a resin obtained by polymerizing dicyclopentadiene using a Friedel-Crafts catalyst such as AlCl3 or BF3.

[0060] Furthermore, the resin used as a raw material for the hydrogenated resin may contain, for example, a resin obtained by copolymerizing a C5 fraction with dicyclopentadiene (DCPD) (C5-DCPD resin). Here, if the dicyclopentadiene-derived component is 50% by mass or more of the total resin, the C5-DCPD resin is considered to be included in the dicyclopentadiene-based resin. If the dicyclopentadiene-derived component is less than 50% by mass of the total resin, the C5-DCPD resin is considered to be included in the C5-based resin. The same applies to cases where a small amount of a third component or the like is contained.

[0061] From the viewpoint of increasing the compatibility between the rubber component and the hydrogenated resin and further improving the low loss properties and handling stability of a tire, the hydrogenated resin is preferably at least one selected from the group consisting of hydrogenated C5 resins, hydrogenated C5-C9 resins, and hydrogenated dicyclopentadiene resins (hydrogenated DCPD resins), more preferably at least one selected from the group consisting of hydrogenated C5 resins and hydrogenated C5-C9 resins, and even more preferably a hydrogenated C5 resin. When the hydrogenated resin is at least one selected from the group consisting of hydrogenated C5 resins, hydrogenated C5-C9 resins, and hydrogenated dicyclopentadiene resins, the low loss properties and handling stability of the tire can be further improved when the rubber composition is applied to a tire.

[0062] In the rubber composition, the content of the hydrogenated resin is preferably in the range of 5 to 50 parts by mass per 100 parts by mass of the rubber component. When the content of the hydrogenated resin is 5 parts by mass or more per 100 parts by mass of the rubber component, the effect of the hydrogenated resin is sufficiently exhibited, and when the content is 50 parts by mass or less, precipitation of the hydrogenated resin from the tire is suppressed, allowing the effect of the hydrogenated resin to be sufficiently exhibited. From the viewpoint of further enhancing the effects of the hydrogenated resin, the content of the hydrogenated resin in the rubber composition is preferably 6 parts by mass or more, more preferably 7 parts by mass or more, and even more preferably 8 parts by mass or more, per 100 parts by mass of the rubber component. Also, from the viewpoint of suppressing precipitation of the hydrogenated resin from the tire and suppressing deterioration of the tire appearance, the content of the hydrogenated resin in the rubber composition is preferably 47 parts by mass or less, more preferably 43 parts by mass or less, and even more preferably 40 parts by mass or less, per 100 parts by mass of the rubber component.

[0063] (filler) The rubber composition of this embodiment contains a filler. The filler has the effect of reinforcing the rubber composition. The content of the filler in the rubber composition is preferably in the range of 40 to 125 parts by mass per 100 parts by mass of the rubber component. If the content of the filler in the rubber composition is 40 parts by mass or more per 100 parts by mass of the rubber component, the rubber composition is sufficiently reinforced. If the content of the filler in the rubber composition is 125 parts by mass or less, the modulus of elasticity of the rubber composition does not become too high, and the steering stability of the tire is improved. From the viewpoint of further improving the steering stability of the tire, the content of the filler in the rubber composition is preferably 45 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 55 parts by mass or more per 100 parts by mass of the rubber component. Furthermore, from the viewpoint of further improving the low loss properties of the tire, the content of the filler in the rubber composition is preferably 110 parts by mass or less, more preferably 100 parts by mass or less, and more preferably 90 parts by mass or less per 100 parts by mass of the rubber component.

[0064] --silica-- The filler contains silica. When the rubber composition contains silica, it is possible to improve low loss properties and improve handling stability when the rubber composition is applied to a tire. Examples of the silica include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate. Among these, wet silica is preferred. These silicas may be used alone or in combination of two or more.

[0065] The silica has a nitrogen adsorption specific surface area (BET method) of 130 m 2 / g or more 330m 2 It is preferable that the SiO2 content is less than 1 / g. The nitrogen adsorption specific surface area of ​​silica (BET method) is 130m 2 When the silica has a nitrogen adsorption specific surface area (BET method) of 330 m / g or more, the rubber composition is sufficiently reinforced. 2 When the modulus of elasticity is less than 1 / g, the elastic modulus of the rubber composition does not become too high, and the steering stability of the tire is improved. In addition, from the perspective of further improving the handling stability of the tire, the nitrogen adsorption specific surface area of ​​the silica (BET method) is 180m 2 / g or more is more preferable, and 190m 2 / g or more. From the viewpoint of further improving the low loss property of the tire, the nitrogen adsorption specific surface area (BET method) of silica is 300 m 2 / g or less is more preferable, and 280m 2 / g or less is more preferable, and 270m 2 It is more preferable that the saturation coefficient is 1 / g or less. The silica has a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 100 m 2 / g or more, and 150m 2 / g or more is more preferable, and 180m 2 It is more preferable that the silica has a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 300 m / g or more. 2 / g or less, and 2 / g or less is more preferable, and 250m 2 It is more preferable that the saturation coefficient is 1 / g or less.

[0066] From the viewpoint of further improving the low loss properties of the tire, the content of silica in the filler is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more.

[0067] From the viewpoint of improving the steering stability of the tire, the content of silica in the rubber composition is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and even more preferably 40 parts by mass or more, per 100 parts by mass of the rubber component. Also, from the viewpoint of improving the low loss properties of the tire, the content of silica in the rubber composition is preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less, per 100 parts by mass of the rubber component.

[0068] --Carbon Black-- The filler preferably contains carbon black, provided that the carbon black is contained in such a range that the silica content in the filler is 80 mass % or more. Carbon black reinforces the vulcanized rubber and improves the abrasion resistance of the vulcanized rubber. The carbon black is not particularly limited, and examples thereof include GPF, FEF, HAF, ISAF, and SAF grade carbon black. These carbon blacks may be used alone or in combination of two or more.

[0069] From the viewpoint of further improving the abrasion resistance of the tire, the content of carbon black in the rubber composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the rubber component. Also, from the viewpoint of improving the low loss properties of the tire, the content of carbon black in the rubber composition is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 9 parts by mass or less, per 100 parts by mass of the rubber component.

[0070] From the viewpoint of suppressing deterioration in rolling resistance when the rubber composition is applied to a tire and further improving performance on ice and handling stability, the ratio of the carbon black content to the silica content (carbon black content / silica content) is preferably 0.05 to 1.2, more preferably 0.07 to 1.0, and particularly preferably 0.08 to 0.7. By setting the carbon black content ratio to 0.05 or more, the strength of the rubber can be increased and handling stability can be further improved when the rubber is applied to a tire, while by setting the carbon black content ratio to 1 or less, deterioration in low heat buildup due to an increase in carbon black can be suppressed and good rolling resistance can be maintained when the rubber is applied to a tire.

[0071] --Other fillers-- The filler may contain inorganic fillers such as clay, talc, calcium carbonate, and aluminum hydroxide in addition to silica and carbon black.

[0072] (Other ingredients) In addition to the rubber component, hydrogenated resin, and filler described above, other components may be appropriately selected and blended into the rubber composition according to purpose or need, provided that the effects of the present invention are not impaired. Examples of other components include additives commonly used in the rubber industry, such as antioxidants, crosslinking accelerators, crosslinking agents, crosslinking accelerator assistants, silane coupling agents, softeners, antiozonants, and surfactants.

[0073] The antioxidant may be any known one and is not particularly limited. Examples include phenol-based antioxidants, imidazole-based antioxidants, and amine-based antioxidants. These antioxidants may be used alone or in combination of two or more. The content of the antioxidant is not particularly limited, and is preferably in the range of 0.1 to 5 parts by mass, more preferably 1 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0074] The crosslinking accelerator may be any known one and is not particularly limited. Examples thereof include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide; sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazyl sulfenamide and Nt-butyl-2-benzothiazyl sulfenamide; guanidine-based vulcanization accelerators such as diphenyl guanidine; thiuram-based vulcanization accelerators such as tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, tetradodecyl thiuram disulfide, tetraoctyl thiuram disulfide, tetrabenzyl thiuram disulfide and dipentamethylene thiuram tetrasulfide; dithiocarbamate-based vulcanization accelerators such as zinc dimethyldithiocarbamate; and zinc dialkyldithiophosphate. The content of the crosslinking accelerator is not particularly limited, and is preferably in the range of 0.1 to 8 parts by mass, more preferably 0.2 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0075] The crosslinking agent may be sulfur, etc. The content of the crosslinking agent is not particularly limited, but is preferably in the range of 0.1 to 8 parts by mass, more preferably 1 to 4 parts by mass, in terms of sulfur content, per 100 parts by mass of the rubber component.

[0076] Examples of the crosslinking accelerator aid include zinc oxide (ZnO) and fatty acids. The fatty acid may be saturated or unsaturated, linear or branched, and the number of carbon atoms of the fatty acid is not particularly limited. Examples include fatty acids having 1 to 30 carbon atoms, preferably 15 to 30 carbon atoms. More specifically, naphthenic acids such as cyclohexanoic acid (cyclohexanecarboxylic acid) and alkylcyclopentanes having side chains; saturated fatty acids such as hexanoic acid, octanoic acid, decanoic acid (including branched carboxylic acids such as neodecanoic acid), dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid (stearic acid); unsaturated fatty acids such as methacrylic acid, oleic acid, linoleic acid, and linolenic acid; and resin acids such as rosin, tall oil acid, and abietic acid. These may be used alone or in combination. In the present invention, zinc oxide and stearic acid are preferably used. The content of the crosslinking accelerator aid is not particularly limited, and is preferably in the range of 0.5 to 8 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0077] Examples of the silane coupling agent include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2 ... Mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzolyl tetrasulfide, 3-triethoxysilylpropyl Pyril methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, 3-octanoylthiopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltri Examples of suitable silane coupling agents include ethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and 3-[ethoxybis(3,6,9,12,15-pentaoxaoctacosan-1-yloxy)silyl]-1-propanethiol (trade name "Si363" manufactured by Evonik Degussa). These silane coupling agents may be used alone or in combination of two or more. The content of the silane coupling agent is not particularly limited, but from the viewpoint of improving the dispersibility of the silica, it is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, per 100 parts by mass of the silica.

[0078] Examples of the softener include naphthenic oils, paraffinic oils, and aromatic oils. The softener can also be used as an extender oil for the rubber component. The content of the softener is not particularly limited, and it is preferable to compound 2 to 50 parts by mass per 100 parts by mass of the rubber component. When the content of the softener is 2 parts by mass or more per 100 parts by mass of the rubber component, the processability of the rubber composition is improved. When the content of the softener is 50 parts by mass or less per 100 parts by mass of the rubber component, the softener is less likely to bleed onto the surface of the rubber product, and sufficient abrasion resistance can be ensured.

[0079] (Method of manufacturing rubber composition) The method for producing the rubber composition is not particularly limited, but the rubber composition can be produced, for example, by blending the above-mentioned rubber component, hydrogenated resin, and filler, and various other components appropriately selected as necessary, and kneading, heating, extruding, etc. The obtained rubber composition can be vulcanized to produce a vulcanized rubber.

[0080] The conditions for the kneading are not particularly limited, and various conditions such as the input volume of the kneading device, the rotation speed of the rotor, the ram pressure, the kneading temperature, the kneading time, the type of kneading device, etc. can be appropriately selected depending on the purpose. Examples of the kneading device include a Banbury mixer, an intermix, a kneader, a roll, etc. that are usually used for kneading rubber compositions.

[0081] The conditions for the heat-in are not particularly limited, and various conditions such as the heat-in temperature, heat-in time, and heat-in device can be appropriately selected depending on the purpose. Examples of the heat-in device include a heat-in roller typically used for heat-in of a rubber composition.

[0082] The extrusion conditions are not particularly limited, and various conditions such as extrusion time, extrusion speed, extrusion device, and extrusion temperature can be appropriately selected depending on the purpose. Examples of the extrusion device include an extruder typically used for extruding rubber compositions. The extrusion temperature can be appropriately determined.

[0083] The vulcanization apparatus, method, conditions, etc. are not particularly limited and can be appropriately selected depending on the purpose. Examples of vulcanization apparatus include a molding vulcanizer using a mold used for vulcanizing rubber compositions. The vulcanization temperature is, for example, about 100 to 190°C.

[0084] (Uses of rubber compositions) The rubber composition of the present embodiment can be used for various rubber products including tires, and is particularly preferred as a rubber composition for tires.

[0085] <Tires> The tire of this embodiment is characterized by including the rubber composition described above. The tire of this embodiment has low loss properties and excellent steering stability. The tire of the present embodiment is preferably a pneumatic tire. The tire of the present embodiment preferably has the rubber composition in a tread portion, that is, preferably includes tread rubber obtained by vulcanizing the rubber composition.

[0086] The tire may be obtained by molding an unvulcanized rubber composition and then vulcanizing it, depending on the type of tire and the components to be applied, or by first obtaining a semi-vulcanized rubber from the unvulcanized rubber composition through a pre-vulcanization step or the like, molding the semi-vulcanized rubber using the semi-vulcanized rubber, and then further vulcanizing the tire. When the tire is a pneumatic tire, the gas to be filled into the pneumatic tire may be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium. [Example]

[0087] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0088] <Analysis method for modified conjugated diene polymers> The vinyl bond amount, bound styrene amount, and peak top molecular weight (Mp) of the modified conjugated diene polymer are measured by the following methods.

[0089] (1) Vinyl bond content (%) 400MHz 1 Measured by H-NMR.

[0090] (2) Bound styrene content (%) 400MHz 1 It is measured by H-NMR measurement.

[0091] (3) Peak top molecular weight (Mp) After the modification reaction, the polystyrene equivalent is determined from the retention time corresponding to the apex of the maximum peak in the GPC curve obtained using gel permeation chromatography (GPC) (manufactured by Viscotek, trade name "Viscotek TDA302") under the following measurement conditions. --GPC measurement conditions-- Column: 2 "TSKgelHHR-H" (Tosoh Corporation) Column temperature: 40℃ Mobile phase: Tetrahydrofuran ·Flow rate: 1.0ml / min Sample concentration: 10mg / 20ml

[0092] <Analysis method for hydrogenated resin> The softening point and weight average molecular weight of the hydrogenated resin are measured by the following method.

[0093] (4) Softening point The softening point of the hydrogenated resin is measured in accordance with JIS-K2207-1996 (ring and ball method).

[0094] (5) Weight average molecular weight The average molecular weight of the hydrogenated resin is measured by gel permeation chromatography (GPC) under the following conditions, and the weight average molecular weight in terms of polystyrene is calculated. --GPC measurement conditions-- Column temperature: 40℃ ·Injection volume: 10μL Carrier and flow rate: Tetrahydrofuran 0.35mL / min Sample preparation: Dissolve approximately 0.02 g of hydrogenated resin in 20 mL of tetrahydrofuran.

[0095] <Comparative Example 1> Each component was blended according to the formulation shown in Table 1 and kneaded using a Banbury mixer to prepare a rubber composition sample. The blending amounts in Table 1 are shown in parts by mass relative to 100 parts by mass of the rubber component. The obtained rubber composition sample was subjected to a production vulcanization step (temperature during vulcanization: 150°C) to obtain a vulcanized rubber composition sample. The modified conjugated diene polymer A contained in the sample of the rubber composition was prepared according to the following method.

[0096] (Method for producing modified conjugated diene polymer A) A cyclohexane solution of 1,3-butadiene and a cyclohexane solution of styrene were added to a dried, nitrogen-purged 800 mL pressure-resistant glass vessel so that the total weight of the mixture was 67.5 g of 1,3-butadiene and 7.5 g of styrene. 0.6 mmol of 2,2-ditetrahydrofurylpropane and 0.8 mmol of n-butyllithium were then added, and polymerization was carried out at 50 °C for 1.5 hours. At this point, the polymerization conversion rate of the polymerization reaction system reached nearly 100%, and 0.72 mmol of [N,N-bis(trimethylsilyl)-(3-amino-1-propyl)](methyl)(diethoxy)silane was added, and the modification reaction was carried out at 50 °C for 30 minutes. The reaction was then terminated by adding 2 mL of a 5% by weight solution of 2,6-di-t-butyl-p-cresol (BHT) in isopropanol. The mixture was then dried in the usual manner to obtain a modified conjugated diene-based polymer A. The resulting modified conjugated diene polymer A had a bound styrene content of 10% by mass, a vinyl bond content of 40% by mass in the butadiene moiety, and a peak top molecular weight (Mp) of 215×10 3 is.

[0097] Example 1 Each component is blended according to the formulation shown in Table 1 and kneaded using a Banbury mixer to prepare a rubber composition sample. The blending amounts in Table 1 are shown in parts by mass relative to 100 parts by mass of the rubber component. Each sample of the resulting rubber composition is subjected to a production vulcanization step (temperature during vulcanization: 150°C) to obtain a sample of vulcanized rubber composition. The modified conjugated diene polymer B contained in the sample of the rubber composition is prepared according to the following method.

[0098] (Method for producing modified conjugated diene polymer B) (i) First, a modifier compound (M-1) is obtained under the following conditions. In a 100 mL recovery flask, 80 mL of toluene solvent, 4.55 g (33.92 mmol) of terephthalaldehyde, and 15.02 g (67.84 mmol) of 3-aminopropyltriethoxysilane were charged, and refluxed at 120°C using a Dean-Stark apparatus. After all the water had been removed, refluxing was continued for another 2 hours, after which the mixture was filtered, and the toluene solvent was distilled off under reduced pressure. The purity of the product was confirmed by 1 After estimating by H-NMR spectrum analysis and GC / MS analysis, the compound is used as a modifier compound (M-1) for the modified conjugated diene polymer B. 1 H-NMR (solvent: CDCl3) chemical shift δ: 8.26 ppm (N=C H -Ph, 2H), 7.73 ppm (hydrogen on benzene ring, 4H), 3.80 ppm (CH3-C H 2-O-, 12H), 3.61ppm(Si-CH2-CH2-C H 2-N, 4H), 1.83 ppm (Si-CH2-C H 2-CH2-N, 4H), 1.20 ppm (C H3-CH2-O, 18H), 0.67 ppm (Si-C H 2-CH2-CH2-N, 4H) [ka]

[0099] (ii) Next, 2,000 g of cyclohexane, 30.3 g of tetrahydrofuran, 23 g of styrene, and 420 g of 1,3-butadiene were charged into a nitrogen-purged 5-liter autoclave reactor. After adjusting the temperature of the reactor contents to 10°C, 6.26 mmol of n-butyllithium as a polymerization initiator was added, followed by 6.26 mmol of N-(trimethylsilyl)piperazine as a compound having a functional group that interacts with silica, to initiate polymerization. The polymerization was carried out under adiabatic conditions, with a maximum temperature reaching 85°C. When the polymerization conversion rate reached 99% (20 minutes after the start of polymerization), 10 g of 1,3-butadiene was added over 2 minutes, followed by the addition of 2.79 mmol of the modifier compound (M-1), and the reaction was continued for 15 minutes. Then, 3.96 g of 2,6-di-tert-butyl-p-cresol is added to the polymer solution containing the modified conjugated diene polymer, and the solvent is then removed by steam stripping. The resulting mixture is then dried with a heated roll adjusted to 110°C to obtain modified conjugated diene polymer B. The resulting modified conjugated diene polymer B had a bound styrene content of 5% by mass, a vinyl bond content of 40% by mass in the butadiene moiety, and a peak top molecular weight (Mp) of 120×10 3 is.

[0100] <Evaluation of Rubber Composition> The vulcanized rubber composition samples were subjected to the following evaluations. The evaluation results are shown in Table 1.

[0101] (6) Steering stability For each sample, a high-frequency dynamic viscoelasticity measuring device manufactured by Metravib was used to measure the storage shear modulus G' (Pa) under conditions of 30°C, 72% strain, and a frequency of 15 Hz. The values ​​are expressed as an index, with the G' value of Comparative Example 1 taken as 100, and are shown in Table 1. Note that a larger index value indicates a larger G' value, which indicates better steering stability when applied to a tire.

[0102] (7) Low loss The loss tangent (tanδ) of each sample was measured using a high-frequency dynamic viscoelasticity measuring device manufactured by Metravib under conditions of 30°C, 1% strain, and a frequency of 15 Hz. The loss tangent (tanδ) was expressed as an index with the reciprocal of the tanδ value of Comparative Example 1 set to 100, and is shown in Table 1. Note that the larger the index value, the smaller the tanδ value, indicating excellent low-loss properties when applied to a tire.

[0103] [Table 1]

[0104] *1 SBR: Styrene-butadiene rubber, manufactured by JSR Corporation, product name "HP755", oil-extended rubber blended with 37.5 parts by mass of extender oil for 100 parts by mass of rubber component. *2 Modified conjugated diene polymer A: Modified styrene-butadiene rubber, Modified conjugated diene polymer A synthesized by the above method, Bound styrene content = 10% by mass, Vinyl bond content in butadiene part = 40% by mass, Peak top molecular weight (Mp) = 215 × 10 3 *3 Modified conjugated diene polymer B: Modified styrene-butadiene rubber, modified conjugated diene polymer B synthesized by the above method, bound styrene content = 5 mass%, vinyl bond content in butadiene part = 40 mass%, peak top molecular weight (Mp) = 120 × 10 3 *4 Carbon black: Asahi Carbon Co., Ltd., product name "#80" *5 Silica: Tosoh Silica Corporation, product name "Nipsil AQ" *6 Anti-aging agent A: Sumitomo Chemical Co., Ltd., product name "Antigen 6C" *7 Antioxidant B: Seiko Chemical Co., Ltd., product name "Nonflex RD-S" *8 Hydrogenated resin: Hydrogenated C5 resin, manufactured by Eastman, trade name "Impera E1780", softening point = 130°C, weight average molecular weight (Mw) = 800g / mol *9 Silane coupling agent: Evonik, product name "Si363" *10 Vulcanization accelerator A: Sansera DM-TG, manufactured by Sanshin Chemical Industry Co., Ltd. *11 Vulcanization accelerator B: Sumitomo Chemical Co., Ltd., product name "Soxinor DG" *12 Vulcanization accelerator C: Sanshin Chemical Industry Co., Ltd., product name "Suncerer CM-G" *13 Other: The total amount of stearic acid, oil, wax, fatty acid metal salt, workability improver, retarder, and the blending amount of each component are the same in Example 1 and Comparative Example 1.

[0105] The results in Table 1 show that the rubber composition of Example 1 is superior to the rubber composition of Comparative Example 1 in handling stability and low loss. [Industrial Applicability]

[0106] The rubber composition of the present invention can be used for various rubber products, including tires.

Claims

1. A rubber composition comprising a rubber component, a hydrogenated resin, and a filler, The rubber component comprises a conjugated diene polymer having an active terminal and a group "-CR １ = N-A １ " and the group "-N=CR １ -A １ ” (However, R １ is a hydrogen atom or a hydrocarbyl group, A １ is a monovalent group having an alkoxysilyl group, and a compound [M] having a total of two or more groups selected from The hydrogenated resin has a softening point of more than 110°C and a weight average molecular weight of 200 to 1200 g / mol in terms of polystyrene; The filler comprises silica. A rubber composition characterized by:

2. The rubber composition according to claim 1, wherein the modified conjugated diene polymer is represented by the following general formula (3): 【Chemistry 1】 [In formula (3), R ２ is a hydrocarbyl group having 1 to 20 carbon atoms, and R ６ is a hydrocarbyloxy group having 1 to 20 carbon atoms or a modified or unmodified conjugated diene polymer chain, R ４ is an alkanediyl group having 1 to 20 carbon atoms, and Z is a group represented by the following general formula (4) or (5): ５ is an m-valent hydrocarbyl group having 1 to 20 carbon atoms, or an m-valent group having 1 to 20 carbon atoms and having at least one atom selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms and having no active hydrogen. n is an integer of 1 to 3, and m is an integer of 2 to 10. In the formula, multiple R ２ , R ４ , R ６ , Z, and n may be the same or different.] 【Chemistry 2】 [In formulas (4) and (5), R １ represents a hydrogen atom or a hydrocarbyl group, and Poly represents a modified or unmodified conjugated diene polymer chain. ５ indicates a bond bonded to the

3. The rubber composition according to claim 1 or 2, wherein the modified conjugated diene polymer has an aromatic vinyl unit and a conjugated diene unit, and the proportion of the aromatic vinyl unit is 10 mass % or less.

4. The modified conjugated diene polymer has a peak top molecular weight (Mp) of 1.0×10 ６ The rubber composition according to any one of claims 1 to 3, wherein the tensile strength is less than 1000 kJ / cm.

5. The hydrogenated resin is hydrogenated C ５ based resin, hydrogenated C ５ -C ９ The rubber composition according to any one of claims 1 to 4, wherein the rubber composition is at least one selected from the group consisting of a dicyclopentadiene-based resin and a hydrogenated dicyclopentadiene-based resin.

6. A tire comprising the rubber composition according to any one of claims 1 to 5.

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