Rubber composition and tire rubber composition

Abstract

The present invention relates to a rubber composition containing 100 parts by mass of a solid rubber (A), 5-30 parts by mass of a modified liquid diene-based polymer (B) having a modified group represented by formula (I) [in the formula, X represents N, O, or S; R1 represents a divalent hydrocarbon group; R2 represents a monovalent hydrocarbon group; R3 represents a divalent organic group containing O and C; R4 represents a hydrogen atom or an alkyl group; m represents an integer of 0-2; n represents an integer of 1-3; m+n = 3; and * represents a dangling bond], and 30-150 parts by mass of a filler (C).

Description

Rubber composition and tire rubber composition 【0001】 This disclosure relates to rubber compositions and tire rubber compositions. 【0002】 Conventionally, rubber compositions with improved mechanical strength achieved by compounding fillers such as silica and carbon black with rubber components such as natural rubber and styrene-butadiene rubber have been widely used in applications requiring wear resistance and mechanical strength, such as tires. It has been pointed out that the dispersion state of the fillers in the crosslinked material of these rubber compositions may affect the physical properties of the crosslinked material (for example, wear resistance and wet grip in tire rubber compositions). Therefore, various studies have been conducted on adding modified diene polymers to rubber compositions for purposes such as improving the dispersibility of fillers in the rubber composition (see, for example, Patent Documents 1 to 4). 【0003】 Furthermore, Patent Document 5 discloses a tire rubber composition containing diene rubber and silica, which was developed with the aim of improving the wet grip performance when used in tires. Also, Patent Document 6 discloses a polybutadiene-based epoxy resin curing agent. 【0004】 Japanese Patent Publication No. 2019-77803, Japanese Patent Publication No. 2019-206643, International Publication No. 2016-104628, Japanese Patent Publication No. 2010-174109, Japanese Patent Publication No. 2019-52215, Japanese Patent Publication No. 59-6213 【0005】 According to the present inventors, when a modified diene polymer having a silane coupling group, such as those disclosed in Patent Documents 1 and 3, is used in a rubber composition, the dispersibility of the filler can be improved, but the vulcanization time may be prolonged. 【0006】 Therefore, the object of this disclosure is to provide a rubber composition that has filler dispersibility while being able to shorten the vulcanization time, which was a problem when the modified diene polymer was incorporated into the rubber composition. 【0007】The inventors of the present invention have conducted extensive studies to solve the above problems and have completed the invention of the present disclosure. That is, the present disclosure includes the following preferred embodiments. [1] 100 parts by mass of solid rubber (A), formula (I): [In the formula, X represents N, O, or S, R １ represents a divalent hydrocarbon group, R ２ represents a monovalent hydrocarbon group, R ３ represents a divalent organic group containing O and C, R ４ represents a hydrogen atom or an alkyl group, m represents an integer of 0 to 2, n represents an integer of 1 to 3, provided that m + n = 3, and * represents a bond] A rubber composition containing 5 to 30 parts by mass of a modified liquid diene polymer (B) having a modifying group represented by and 30 to 150 parts by mass of a filler (C). [2] R ３ in formula (I) is a group in which at least one methylene group (—CH ２ —) contained in the divalent organic group is substituted with at least one group selected from the group consisting of —O—, —C(═O)—, —C(═O)—O—, and —O—C(═O)—. The rubber composition according to [1]. [3] The modifying group represented by formula (I) is formula (II): [In the formula, R １ , R ２ , R ４ , m, n, and * are the same as R １ , R ２ , R ４ , m, n, and * in the above formula (I), and R ５The rubber composition according to [1] or [2], wherein the modifying group is represented by [representing at least one selected from the group consisting of an alkylene group having 1 to 12 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, a hydrocarbon group having 3 to 12 carbon atoms including an alicyclic structure having 3 to 12 carbon atoms, and a hydrocarbon group having 6 to 12 carbon atoms including an aromatic ring having 6 to 12 carbon atoms]. [4] The rubber composition according to any one of [1] to [3], wherein the weight-average molecular weight of the modified liquid diene polymer (B) is 4,000 to 150,000. [5] The rubber composition according to any one of [1] to [4], wherein the modified liquid diene polymer (B) contains 20 to 100% by mass of structural units derived from butadiene relative to the total amount of the modified liquid diene polymer. [6] The rubber composition according to [5], wherein the structural units derived from butadiene include 0 to 70 mol% of 1,2-bonding units having vinyl groups relative to the total amount of 1,4-bonding units and 1,2-bonding units having vinyl groups in the structural units derived from butadiene. [7] The rubber composition according to any one of [1] to [6], wherein the average number of modifying groups represented by formula (I) in the modified liquid diene polymer (B) is 1 to 30 per molecule of the modified liquid diene polymer. [8] The rubber composition according to any one of [1] to [7], wherein the solid rubber (A) is at least one selected from the group consisting of natural rubber, styrene-butadiene rubber, butadiene rubber, and isoprene rubber. [9] The rubber composition according to any one of [1] to [8], wherein the solid rubber (A) includes 0.1 to 70% by mass of structural units derived from styrene relative to the total amount of solid rubber (A).

[10] The rubber composition according to any one of [1] to [9], wherein the solid rubber (A) is styrene-butadiene rubber having a weight-average molecular weight of 100,000 to 2,500,000.

[11] The rubber composition according to any one of [1] to

[10] , wherein the filler (C) is carbon black and / or silica.

[12] A tire rubber composition comprising the rubber composition according to any one of [1] to

[11] and / or a crosslinked product of the rubber composition according to any one of [1] to

[11] . 【0008】 According to the present invention, it is possible to provide a rubber composition that has filler dispersibility while shortening the vulcanization time, which was a problem when the modified diene polymer was incorporated into the rubber composition. 【0009】 The embodiments of this disclosure will be described in detail below. However, the scope of this disclosure is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of this disclosure. In this specification, the expression "x to y" (where x and y are numbers) which represents a numerical range means "more than or equal to x and less than or equal to y". 【0010】 The rubber composition of this disclosure contains 100 parts by mass of solid rubber (A), 5 to 30 parts by mass of a modified liquid diene polymer (B) having a modifying group represented by formula (I) described later, and 30 to 150 parts by mass of filler (C). 【0011】 (Solid rubber (A)) The rubber composition of the present disclosure comprises at least one solid rubber (A). 【0012】 Solid rubber (A) refers to rubber that can be handled in a solid state at 20°C. The Mooney viscosity ML(1+4) of solid rubber (A) at 100°C is usually 20 to 200. Examples of solid rubber (A) include natural rubber, styrene-butadiene rubber (hereinafter also referred to as "SBR"), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber, acrylic rubber, fluororubber, and urethane rubber. Among these solid rubbers (A), at least one selected from the group consisting of natural rubber, SBR, butadiene rubber, and isoprene rubber is preferred, and at least one selected from the group consisting of natural rubber and SBR is even more preferred. These solid rubbers (A) may be used individually or in combination of two or more. 【0013】 The number-average molecular weight (Mn) of the solid rubber (A) is preferably 80,000 or more, and more preferably in the range of 100,000 to 3,000,000, from the viewpoint of fully exhibiting the properties of the resulting rubber composition and crosslinked product. In this specification, the number-average molecular weight is the number-average molecular weight on a polystyrene basis measured by gel permeation chromatography (GPC). 【0014】Examples of natural rubber include TSR (Technically Specified Rubber) such as SMR (Malaysian TSR), SIR (Indonesian TSR), and STR (Thai TSR), as well as RSS (Ribbed Smoked Sheet), which are commonly used in the tire industry, and modified natural rubbers such as high-purity natural rubber, epoxidized natural rubber, hydroxylated natural rubber, hydrogenated natural rubber, and grafted natural rubber. Among these, SMR20, STR20, and RSS#3 are preferred due to their low variation in quality and ease of availability. These natural rubbers may be used individually or in combination of two or more. 【0015】 As for SBR, general types used in tire applications can be used. Specifically, those with a styrene content of 0.1 to 70% by mass are preferred, more preferably 5 to 50% by mass, and even more preferably 15 to 35% by mass. Furthermore, those with a vinyl content of 0.1 to 65% by mass are preferred, and more preferably 0.1 to 60% by mass. In this specification, "vinyl content" in SBR refers to the proportion of 1,2-bonds contained in the butadiene structural unit. １ This can be determined by measuring H-NMR. 【0016】 The weight-average molecular weight (Mw) of SBR is preferably 100,000 to 2,500,000, more preferably 150,000 to 2,000,000, and even more preferably 200,000 to 1,500,000. Within this range, both processability and mechanical strength can be achieved. In this specification, the weight-average molecular weight is the weight-average molecular weight on a polystyrene basis determined from gel permeation chromatography (GPC) measurements. 【0017】 The glass transition temperature of SBR, as determined by differential thermal analysis, is preferably -95 to 0°C, and more preferably -95 to -5°C. By setting the glass transition temperature within this range, the viscosity of SBR can be kept within a range that is easy to handle. 【0018】SBR is obtained by copolymerizing styrene and butadiene. There are no particular restrictions on the method of producing SBR; emulsion polymerization, solution polymerization, gas-phase polymerization, and bulk polymerization can all be used, but among these methods, emulsion polymerization and solution polymerization are preferred. Emulsion-polymerized styrene-butadiene rubber (hereinafter also referred to as E-SBR) can be produced by known or similar conventional emulsion polymerization methods. For example, it can be obtained by emulsifying and dispersing predetermined amounts of styrene and butadiene monomers in the presence of an emulsifier and then emulsion polymerization with a radical polymerization initiator. 【0019】 Solution-polymerized styrene-butadiene rubber (hereinafter also referred to as S-SBR) can be produced by conventional solution polymerization methods. For example, it can be obtained by polymerizing styrene and butadiene using an anionically polymerizable active metal in a solvent, optionally in the presence of a polar compound. 【0020】 Examples of solvents include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; and aromatic hydrocarbons such as benzene and toluene. These solvents are usually used in a range where the monomer concentration is 1 to 50% by mass. 【0021】 Examples of anionically polymerizable active metals include alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium, and barium; and lanthanide rare earth metals such as lanthanum and neodymium. Among these active metals, alkali metals and alkaline earth metals are preferred, with alkali metals being more preferred. Furthermore, among alkali metals, organoalkali metal compounds are more preferably used. 【0022】Examples of organoalkali metal compounds include organomonolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenithium; polyfunctional organolithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, and 1,3,5-trilithiobenzene; and sodium naphthalene and potassium naphthalene. Among these, organolithium compounds are preferred, and organomonolithium compounds are more preferred. The amount of organoalkali metal compound used is appropriately determined according to the required molecular weight of S-SBR. Organoalkali metal compounds can also be reacted with secondary amines such as dibutylamine, dihexylamine, and dibenzylamine to be used as organoalkali metal amides. 【0023】 The polar compounds used are not particularly limited, as long as they are commonly used in anionic polymerization to adjust the microstructure of the butadiene moiety and the distribution of styrene within the copolymer chain without deactivating the reaction. Examples include ether compounds such as dibutyl ether, tetrahydrofuran, and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides, phosphine compounds, and the like. 【0024】 The polymerization reaction temperature is typically in the range of -80 to 150°C, preferably 0 to 100°C, and more preferably 30 to 90°C. The polymerization method may be batch or continuous. Furthermore, in order to improve the random copolymerization of styrene and butadiene, it is preferable to continuously or intermittently supply styrene and butadiene into the reaction solution so that the composition ratio of styrene and butadiene in the polymerization system is within a specific range. 【0025】 The polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization stopper. After stopping the polymerization reaction, the polymerization solution can be separated from the solvent by direct drying or steam stripping to recover the desired S-SBR. Alternatively, the polymerization solution and the spreading oil may be mixed beforehand and recovered as oil-spread rubber before removing the solvent. 【0026】As long as the effects of the present invention are not impaired, modified SBRs in which functional groups have been introduced may be used as the SBR. Examples of functional groups include amino groups, alkoxysilyl groups, hydroxyl groups, epoxy groups, carboxyl groups, and the like. 【0027】 Examples of methods for producing modified SBR include adding a coupling agent that can react with the polymerization active end, such as tin tetrachloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 2,4-tolidylenediisocyanate, or a polymerization end modifier such as 4,4'-bis(diethylamino)benzophenone, N-vinylpyrrolidone, or other modifiers described in Japanese Patent Application Publication No. 2011-132298, before adding a polymerization inhibitor. In this modified SBR, the position of the polymer into which the functional group is introduced may be at the polymerization end or on a side chain of the polymer chain. 【0028】 As the butadiene rubber, for example, Ziegler-type catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel can be used; lanthanide-type rare earth metal catalysts such as triethylaluminum-organic acid neodymium-Lewis acid; or commercially available butadiene rubber polymerized using an organoalkali metal compound similar to S-SBR can be used. Butadiene rubber polymerized with a Ziegler-type catalyst is preferred because it has a high cis isomer content. Alternatively, butadiene rubber with an ultra-high cis isomer content obtained using a lanthanide-type rare earth metal catalyst may also be used. 【0029】 The vinyl content of butadiene rubber is preferably 0.1 to 50% by mass, more preferably 0.1 to 40% by mass, and even more preferably 1 to 30% by mass. A vinyl content below the above upper limit is preferable from the viewpoint of improving rolling resistance performance. In this specification, "vinyl content" in butadiene rubber means the proportion of 1,2-bonds contained in the butadiene structural unit. １It can be determined by H-NMR measurement. Furthermore, the glass transition temperature of butadiene rubber varies depending on the vinyl content, but it is preferably -40°C or lower, and more preferably -50°C or lower. The glass transition temperature of butadiene rubber can be determined by differential scanning calorimetry (DSC). 【0030】 The weight-average molecular weight (Mw) of butadiene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is within the above range, processability and mechanical strength are good. 【0031】 The butadiene rubber may have a branched structure or polar functional groups in part by using a polyfunctional modifier, such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in its molecule, or an amino group-containing alkoxysilane, as long as it does not impair the effects of the present disclosure. 【0032】 As the isoprene rubber, for example, Ziegler-type catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel can be used; lanthanide-type rare earth metal catalysts such as triethylaluminum-organic acid neodymium-Lewis acid; or commercially available isoprene rubber polymerized using an organoalkali metal compound similar to S-SBR can be used. Isoprene rubber polymerized with a Ziegler-type catalyst is preferred because it has a high cis isomer content. Alternatively, isoprene rubber with an ultra-high cis isomer content obtained using a lanthanide-type rare earth metal catalyst may be used. 【0033】 The vinyl content of the isoprene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. A vinyl content of 50% by mass or less is preferable from the viewpoint of improving rolling resistance performance. There is no particular lower limit to the vinyl content. The glass transition temperature also changes depending on the vinyl content, but it is preferably -20°C or lower, and more preferably -30°C or lower. 【0034】The weight-average molecular weight (Mw) of isoprene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is within the above range, processability and mechanical strength are good. 【0035】 The isoprene rubber may have a branched structure or polar functional groups in part by using a polyfunctional modifier, such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in its molecule, or an amino group-containing alkoxysilane, as long as it does not impair the effects of the present disclosure. 【0036】 In the rubber composition described above, the content of the modified liquid diene polymer (B) per 100 parts by mass of solid rubber (A) is 5 to 30 parts by mass, preferably 8 to 25 parts by mass, more preferably 10 to 20 parts by mass, and even more preferably 12 to 18 parts by mass. When the content of the modified liquid diene polymer (B) is within the above range, the dispersion state of the filler (C) in the rubber composition becomes ideal, improving the rigidity of the resulting composition and crosslinked product, and is thought to result in high grip performance (wet grip and / or ice grip) for tires, for example, and improved handling stability. 【0037】 Furthermore, in the rubber composition described above, the content of solid rubber (A) is preferably 20 to 90% by mass, more preferably 25 to 85% by mass, and even more preferably 30 to 80% by mass, based on the total amount of the rubber composition. When the content of solid rubber (A) is within the above range, a rubber composition with a good balance of grip and abrasion resistance is obtained. 【0038】 (Modified liquid diene polymer (B)) The rubber composition of the present disclosure comprises at least one polymer of formula (I): [In the formula, X represents N, O, or S, and R １ represents a divalent hydrocarbon group, R ２ represents a monovalent hydrocarbon group, R ３ represents a divalent organic group containing O and C, and R ４The modified liquid diene polymer (B) contains a modified group represented by [where m represents a hydrogen atom or alkyl group, m represents an integer from 0 to 2, n represents an integer from 1 to 3, where m + n = 3, and * represents a bond]. Hereinafter, the modified liquid diene polymer (B) will also be referred to as "polymer (B)". 【0039】 Polymer (B) is a polymer containing structural units derived from conjugated diene monomers, modified with a modifying group represented by formula (I), and is liquid at room temperature (25°C). In other words, polymer (B) is a polymer containing structural units derived from conjugated diene monomers, having a modifying group represented by formula (I), and is liquid at room temperature (25°C). 【0040】 Examples of conjugated diene monomers include butadiene, isoprene, and β-farnesene. The modified liquid diene polymer may be a homopolymer of one type of conjugated diene monomer, or a copolymer of two or more types of conjugated diene monomers. 【0041】 The modified liquid diene polymer (B) is a polymer containing structural units derived from a conjugated diene monomer, and may be a homopolymer of one type of conjugated diene monomer, a copolymer of two or more types of conjugated diene monomers, or a copolymer of one or more types of conjugated diene monomers and one or more types of other monomers (e.g., aromatic vinyl compounds). Therefore, polymer (B) may have only structural units derived from one or more types of conjugated diene monomers (e.g., butadiene), or it may have structural units derived from aromatic vinyl compounds in addition to structural units derived from conjugated diene monomers. Examples of aromatic vinyl compounds include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-tert-butylstyrene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, 4-methoxystyrene, and the like. If polymer (B) is a copolymer, it may be a random copolymer or a block copolymer. 【0042】 The amount of structural units derived from conjugated diene monomers in polymer (B) is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass, relative to the total amount of polymer (B), from the viewpoint of vulcanization reactivity with solid rubber (A) and fluidity. 【0043】 The conjugated diene monomer preferably includes butadiene; in other words, polymer (B) preferably contains structural units derived from butadiene. 【0044】 In a preferred embodiment of the present disclosure, the polymer (B) includes structural units (B-1) derived from butadiene. The amount of structural units (B-1) derived from butadiene is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 35 to 100% by mass, even more preferably 40 to 100% by mass, and particularly preferably 50 to 100% by mass, relative to the total amount of polymer (B), from the viewpoint of vulcanization reactivity with solid rubber (A). 【0045】 The amount of structural units derived from conjugated diene monomers and the amount of structural units derived from butadiene (B-1) in the modified liquid diene polymer (B) are: １ H-NMR and １３ It can also be calculated by measuring C-NMR, or by analyzing the amount of conjugated diene monomer or butadiene monomer in the monomer mixture used when producing the modified liquid diene polymer. 【0046】 The structural unit (B-1) derived from butadiene is not particularly limited as long as it is a structural unit derived from the monomer 1,3-butadiene. Examples include 1,2-bonding units, 1,4-bonding units (cis-1,4-bonding units and trans-1,4-bonding units), and structural units to which a modifying group is attached. Note that each of the 1,2-bonding units, cis-1,4-bonding units, and trans-1,4-bonding units has a vinyl group in the structural unit derived from butadiene. Furthermore, as an example of a structural unit to which a modifying group is attached, a structural unit obtained by attaching a modifying group to the portion derived from the vinyl group in the 1,2-bonding unit is included, and this structural unit does not have a vinyl group. 【0047】 In a preferred embodiment of the present disclosure, the amount of vinyl-grouped 1,2-bonding units relative to the total amount of 1,4-bonding units and vinyl-grouped 1,2-bonding units in the structural unit (B-1) derived from butadiene is preferably 0 to 70 mol%, more preferably 5 to 70 mol%, and even more preferably 5 to 68 mol%, from the viewpoint of handling properties (viscosity). The amounts of vinyl-grouped 1,2-bonding units, 1,4-bonding units, cis-1,4-bonding units, and trans-1,4-bonding units, described later, are, respectively: １ It can be measured by 1H-NMR and infrared absorption spectroscopy, and specifically by the method described in the examples. 【0048】 The structural units (B-1) derived from butadiene preferably include structural units in which a modifying group represented by formula (I) is bonded to the portion derived from the vinyl group in the 1,2-bonding unit. The amount of the structural units is preferably 0.1 to 15 mol%, more preferably 1 to 10 mol%, and even more preferably 2 to 9 mol%, relative to the total amount of structural units derived from butadiene. The amount of the structural units can be calculated from the molecular weight of each monomer constituting the modified liquid diene polymer (B), the weight-average molecular weight of the modified liquid diene polymer (B), the approximate number of monomers constituting the modified liquid diene polymer (B), the approximate number of each bonding unit, and the average number of modifying groups obtained by the method described later. 【0049】 The amount of 1,4-bonding units among the structural units (B-1) derived from butadiene is preferably 30 to 100 mol%, more preferably 30 to 95 mol%, and even more preferably 32 to 95 mol%, relative to the total amount of structural units derived from butadiene, from the viewpoint of handling properties and the manufacturability of polymers having a modifying group represented by formula (I). The amount of 1,4-bonding units can be obtained by subtracting the amount of 1,2-bonding units from the amount of structural units derived from butadiene. 【0050】In a preferred embodiment of the present disclosure, the modified liquid diene polymer (B) comprises a structural unit (B-1) derived from butadiene, wherein the amount of cis-1,4-bonding units relative to the total amount of 1,4-bonding units in the structural unit (B-1) is preferably 20 to 60 mol%, more preferably 30 to 50 mol%, and even more preferably 33 to 45 mol%. 【0051】 In a preferred embodiment of the present disclosure, the modified liquid diene polymer (B) comprises a structural unit (B-1) derived from butadiene, wherein the amount of trans-1,4-bonding units relative to the total amount of 1,4-bonding units in the structural unit (B-1) is preferably 30 to 80 mol%, more preferably 50 to 70 mol%, and even more preferably 55 to 67 mol%. 【0052】 The weight-average molecular weight of polymer (B) is preferably 4,000 to 150,000, more preferably 4,500 to 135,000, even more preferably 4,500 to 125,000, even more preferably 4,500 to 100,000, and particularly preferably 4,500 to 80,000, from the viewpoint of handling (viscosity). In this specification, the weight-average molecular weight of polymer (B) is the weight-average molecular weight on a polystyrene basis determined from gel permeation chromatography (GPC) measurements. When the weight-average molecular weight of polymer (B) is within the above range, it becomes liquid at room temperature, making it easy to handle, resulting in excellent process passability during manufacturing and good economic efficiency. 【0053】 The number-average molecular weight of polymer (B) is preferably 200 to 150,000, more preferably 900 to 135,000, even more preferably 2,000 to 125,000, and particularly preferably 2,000 to 70,000, from the viewpoint of handling, such as stringiness. The number-average molecular weight of polymer (B) can also be measured by gel permeation chromatography (GPC). 【0054】The molecular weight distribution (Mw / Mn) of polymer (B) is preferably 1.0 to 20.0, more preferably 1.0 to 15.0, even more preferably 1.0 to 10.0, even more preferably 1.0 to 5.0, even more preferably 1.0 to 2.5, even more preferably 1.0 to 2.0, particularly preferably 1.0 to 1.5, and most preferably 1.0 to 1.4. When Mw / Mn is within the above range, the variation in viscosity of the resulting polymer (B) is small, which is more preferable. The molecular weight distribution (Mw / Mn) of polymer (B) refers to the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) on a standard polystyrene basis, determined by GPC measurement. 【0055】 The glass transition temperature of polymer (B) is preferably -120 to 10°C, more preferably -100 to 0°C, even more preferably -95 to -5°C, and even more preferably -95 to -10°C, from the viewpoint of handling. The glass transition temperature can be measured using differential scanning calorimetry (DSC). 【0056】 The melt viscosity of polymer (B) at 38°C is preferably 0.1 to 50,000 cP, more preferably 0.1 to 25,000 cP, even more preferably 1 to 18,000 cP, even more preferably 10 to 15,000 cP, and particularly preferably 100 to 15,000 cP, from the viewpoint of handling properties such as stringing. The melt viscosity can be measured using a Brookfield viscometer. 【0057】 Modified liquid diene polymer (B) is of formula (I): [In the formula, X represents N, O, or S, and R １ represents a divalent hydrocarbon group, R ２ represents a monovalent hydrocarbon group, R ３ represents a divalent organic group containing O and C, and R ４The polymer (B) has a modifying group represented by [where m represents a hydrogen atom or alkyl group, m represents an integer from 0 to 2, n represents an integer from 1 to 3, where m + n = 3, and * represents a bond]. This modifying group will also be referred to as modifying group (I) below. Polymer (B) may be modified with one type of modifying group represented by formula (I), or it may be modified with two or more types of modifying groups represented by formula (I). In other words, polymer (B) may have one type of modifying group represented by formula (I), or it may have two or more types of modifying groups represented by formula (I). 【0058】 In formula (I), X represents N, O, or S. From the viewpoint of polymer stability, X is preferably S or N, and more preferably S. 【0059】 R in equation (I) １ This represents a divalent hydrocarbon group. Examples of divalent hydrocarbon groups include at least one selected from the group consisting of alkylene groups and phenylene groups having 1 to 10 carbon atoms. 【0060】 Examples of alkylene groups having 1 to 10 carbon atoms include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, and decylene groups. The alkylene group may be linear or branched. The number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 2 to 6, even more preferably 2 to 5, and even more preferably 3 to 5. The phenylene group is a divalent group having two bonds on a phenyl ring, and the two bonds may be in an ortho, meta, or para relationship with each other. The phenylene group may also be a group in which at least one hydrogen atom bonded to a carbon atom on the phenyl ring is substituted with an alkyl group having 1 to 4 carbon atoms. 【0061】 R in equation (I) １ From the viewpoint of improving the dispersibility of the filler (C), it is preferably an alkylene group having 1 to 10 carbon atoms, more preferably an alkylene group having 2 to 6 carbon atoms, and even more preferably an alkylene group having 2 to 5 carbon atoms. 【0062】 R in equation (I) ２represents a monovalent hydrocarbon group. A monovalent hydrocarbon group represents, for example, an alkyl group having 1 to 20 carbon atoms. An alkyl group having 1 to 20 carbon atoms may be linear or branched. Examples of linear alkyl groups having 1 to 20 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups. Examples of branched alkyl groups include isopropyl, isobutyl, isopentyl, and secondary butyl groups. Tert-butyl group, neopentyl group, secondary pentyl group, tert-pentyl group, isohexyl group, neohexyl group, secondary hexyl group, tert-hexyl group, isoheptyl group, neoheptyl group, secondary heptyl group, tert-heptyl group, isooctyl group, neooctyl group, secondary octyl group, tert-octyl group, isodecyl group, neodecyl group, secondary decyl group, tert-decyl group, isoundecyl group, neoundecyl group, secant Dary undecyl group, tertiary undecyl group, isododecyl group, neododecyl group, secondary dodecyl group, tertiary dodecyl group, isotridecyl group, neotridecyl group, secondary tridecyl group, tertiary tridecyl group, isotetradecyl group, neotetradecyl group, secondary tetradecyl group, tertiary tetradecyl group, isopentadecyl group, neopentadecyl group, secondary pentadecyl group, tertiary pentadecyl group, isohexadecyl group, neohexadecyl Examples include the hexadecyl group, secondary hexadecyl group, tertiary hexadecyl group, isoheptadecyl group, neoheptadecyl group, secondary heptadecyl group, tertiary heptadecyl group, isooctadyl group, neoooctadyl group, secondary octadecyl group, tertiary octyl group, isononadecyl group, neonononadecyl group, secondary nonadecyl group, tertiary nonadecyl group, isoeicosyl group, neoeicosyl group, secondary eicosyl group, tertiary eicosyl group, etc. 【0063】 R in equation (I)２ From the viewpoint of the interaction or reactivity between the filler (C) and the modified liquid diene polymer (B), R is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, and even more preferably an alkyl group having 1 to 10 carbon atoms. ２ From the viewpoint of reactivity, it is preferable that it be linear. Also, R in formula (I) ２ From the viewpoint of storage stability, a branched shape is preferable. ２ When the alkyl group is linear or branched, the preferred number of carbon atoms is preferably 1 to 15, more preferably 1 to 12, and even more preferably 1 to 10. 【0064】 R in equation (I) ３ R represents a divalent organic group containing O and C. Examples of divalent organic groups containing O and C include carbonyl groups, carboxyl groups, and ester groups. ３ From the viewpoint of improving the dispersibility of the filler (C) and improving the vulcanization rate of the rubber composition, preferably, at least one methylene group (-CH) contained in the divalent organic group ２ -) represents a group in which at least one group selected from the group consisting of -O-, -C(=O)-, -C(=O)-O-, and -O-C(=O)-. Specifically, such a group is -O-R ５ -, -R ５ -O-, -O-R ５ -O-, -OC(=O)-R ５ -, -R ５ -C(=O)-O-, -R ５ -C(=O)-, -OC(=O)-OR ５ - is one example. R in equation (I) ３ From the viewpoint of the interaction or reactivity between the filler (C) and the modified liquid diene polymer, -O-C(=O)-R is preferred. ５ -, -OC(=O)-OR ５ - and - OR - R ５ - At least one selected from the group consisting of -O-R ５ - is the case. 【0065】 Here, R ５This represents at least one selected from the group consisting of alkylene groups having 1 to 12 carbon atoms, alkenylene groups having 2 to 12 carbon atoms, hydrocarbon groups containing alicyclic structures having 3 to 12 carbon atoms, and hydrocarbon groups containing aromatic rings having 6 to 12 carbon atoms. 【0066】 Examples of alkylene groups having 1 to 12 carbon atoms include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, and decylene groups. The alkylene group may be linear or branched. The number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 6, even more preferably 2 to 6, and even more preferably 2 to 5. The phenylene group is a divalent group having two bonds on a phenyl ring, and the two bonds may be in an ortho, meta, or para relationship with each other. The phenylene group may be a group in which at least one hydrogen atom bonded to a carbon atom on the phenyl ring is substituted with an alkyl group having 1 to 4 carbon atoms. 【0067】 Examples of alkenylene groups having 2 to 12 carbon atoms include those obtained by replacing at least one -C-C- bond with an -C=C- bond among the alkylene groups having 1 to 12 carbon atoms exemplified above. Examples of alkenylene groups having 2 to 12 carbon atoms include ethylene, propene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, butadiene, hexadiene, octadiene, 1,2,3-butatriene, 1,2,3-propatotriene, 1,3,5-hexatriene, 1,3,5-decatriene, 1,3,5-dodecatriene, 1,2,3,4-butatetraene, 1,3,5,7-octatetraene, 1,3,5,7-decatetraene, and 1,3,5,7-dodecatetraene. The number of carbon atoms in the alkenylene group is preferably 2 to 10, more preferably 2 to 8, and even more preferably 2 to 6. 【0068】Examples of hydrocarbon groups containing an alicyclic structure with 3 to 12 carbon atoms include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, cyclododecane, and other cycloalkanes. The number of carbon atoms in the hydrocarbon group containing the alicyclic structure is preferably 3 to 10, more preferably 3 to 8, and even more preferably 3 to 6. 【0069】 Examples of hydrocarbon groups containing an aromatic ring having 6 to 12 carbon atoms include the phenylene group, which is a divalent group having two bonds on the phenyl ring, and the two bonds may be in an ortho, meta, or para relationship with each other. The phenylene group may also be a group in which at least one hydrogen atom bonded to a carbon atom on the phenyl ring is substituted with an alkyl group having 1 to 4 carbon atoms, such as the methylphenylene group, ethylphenylene group, propylphenylene group, and butylphenylene group. 【0070】 R in equation (I) ５ The alkylene group having 1 to 12 carbon atoms is preferred, an alkylene group having 1 to 10 carbon atoms is more preferred, an alkylene group having 1 to 6 carbon atoms is even more preferred, an alkylene group having 2 to 6 carbon atoms is even more preferred, and an alkylene group having 2 to 5 carbon atoms is most preferred. 【0071】 R in equation (I) ４ R represents a hydrogen atom or an alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but from the viewpoint of hydrolysis reactivity, the alkyl group is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably an alkyl group having 1 or 2 carbon atoms. ４ R in formula (I) is preferably a hydrogen atom or a C1 alkyl group. ４ It is preferable that this is a hydrogen atom or a methyl group. 【0072】In formula (I), m represents an integer from 0 to 2, and n represents an integer from 1 to 3, where m + n = 3. From the viewpoint of improving the dispersibility of filler (C) and improving the vulcanization rate of the rubber composition, n is preferably 1 to 2. From the viewpoint of reactivity with filler (C), m is preferably 1 to 2. When m = 2, there are multiple R ２ They may be different or the same. 【0073】 In formula (I), * represents a bond. The bond is preferably bonded to a structural unit derived from a conjugated diene monomer of the modified liquid diene polymer (B), more preferably to a portion derived from a side-chain vinyl group of the structural unit derived from the conjugated diene monomer, and even more preferably to a portion derived from a side-chain vinyl group of a 1,2-bonding unit derived from butadiene. Therefore, the modifying group represented by formula (I) is preferably considered to be contained in the side chain of polymer (B). When * is bonded to a portion derived from a side-chain vinyl group, it is considered that the side-chain vinyl group and the compound that gives the modifying group represented by formula (I) react and bond, and the side-chain vinyl group is considered to be a single bond (alkylene group) due to the bonding of the modifying group. 【0074】 The structure of the modifying group represented by formula (I) can be analyzed, for example, by structural analysis of the resulting polymer using NMR analysis, or by examining the structure of the modifying compound used in the synthesis of the polymer. 【0075】 In one preferred embodiment of this disclosure, the modifying group represented by formula (I) is: [In the formula, R １ , R ２ , R ４ , m, n, and * are R in formula (I) above. １ , R ２ , R ４ , m, n, and * are synonymous, R ５ R is a modified group represented by [which represents at least one selected from the group consisting of alkylene groups having 1 to 12 carbon atoms, alkenylene groups having 2 to 12 carbon atoms, hydrocarbon groups having 3 to 12 carbon atoms including an alicyclic structure, and hydrocarbon groups having 6 to 12 carbon atoms including an aromatic ring].５ For example, -OR ５ The same description above applies to divalent groups represented by -. 【0076】 The average number of modifying groups represented by formula (I) (or formula (II)) per molecule of the modified liquid diene polymer is preferably 0.5 to 10, more preferably 0.5 to 7, even more preferably 0.5 to 5, even more preferably 1 to 5, particularly preferably 1 to 4.5, particularly more preferably 1 to 4.5, and extremely preferably 1.5 to 4.5, from the viewpoint of dispersibility of filler (C) in the rubber composition, increasing the vulcanization rate of the rubber composition, improving wet grip and ice grip, and suppressing bleed-out of polymer (B), etc. The average number of modifying groups represented by formula (I) per molecule of the modified liquid diene polymer is １ This can be determined from H-NMR. 【0077】 From the viewpoint of reactivity with the modifying group (I), polymer (B) preferably does not have hydroxyl groups at its terminals. Whether or not the polymer has hydroxyl groups at its terminals can be determined by the hydroxyl value neutralization titration method and infrared absorption spectroscopy (IR) as specified in JIS K 0070-1992. １ This can be confirmed by H-NMR. 【0078】The polymer (B) described above has a modified group having an amino group. Because polymer (B) has an amino group, it has good hydrolysis properties, and is therefore considered to have higher reactivity with filler (C) in the rubber composition of this disclosure compared to a modified group that does not have an amino group. Therefore, it is considered that the rigidity, rolling resistance, wet grip, and ice grip of the rubber composition or its crosslinked product can be improved, and the vulcanization time can be shortened. These properties are also influenced by the type and amount of filler contained in the rubber composition and the molecular weight of polymer (B), but these can be adjusted to a desired range for various purposes required for the rubber composition. According to the rubber composition of this disclosure, it is considered that a rubber composition can be provided that exhibits equivalent or improved rigidity, wet grip, and ice grip, etc., compared to a rubber composition containing a liquid diene polymer modified with a different modified group (e.g., a silane coupling agent group) that does not fall under the modified liquid diene polymer of this disclosure and has a similar weight-average molecular weight, and containing a similar amount of filler, while also having a shortened vulcanization time. 【0079】 Furthermore, polymer (B) is -X-R as shown in formula (I). １ - It has a specific modified group in which a group derived from a silane coupling agent and an amino-modified group are bonded via a - group. -X-R １ -By bonding the modifying group via the - group as described above, entanglement between the polymer (B) and filler (C) is suppressed, allowing more polymer (B) and filler (C) to react, thus improving the dispersibility of filler (C). Furthermore, it is thought that modifying groups of this structure exist not only at the reaction ends of polymer (B) but also bonded to the vinyl group portion linked by 1,2- bonds. Therefore, it is thought that the content of the modifying group can be easily adjusted. Moreover, in the case of X = S, in addition to the above, the modifying group represented by formula (I) can be more strongly bonded to polymer (B), so it is thought that the dispersibility of filler (C) can be maintained for a longer period of time. 【0080】(Method for producing a modified liquid diene polymer) The method for producing the above-mentioned modified liquid diene polymer (B) is not particularly limited. For example, it is preferable to produce an unmodified liquid diene polymer by polymerizing butadiene and other monomers copolymerizable with butadiene as needed, for example by solution polymerization, then react the unmodified liquid diene polymer with a silane coupling agent to produce a liquid diene polymer modified with a silane coupling group, and further react the polymer with a modified compound having an amino group. 【0081】 For solution polymerization, known or similar methods can be applied. For example, a monomer containing butadiene is polymerized in a solvent using a Ziegler catalyst, a metallocene catalyst, an anionically polymerizable active metal, or an active metal compound, and optionally in the presence of a polar compound. 【0082】 Examples of solvents include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; and aromatic hydrocarbons such as benzene, toluene, and xylene. 【0083】 Examples of anionically polymerizable active metals include alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium, and barium; and lanthanide rare earth metals such as lanthanum and neodymium. Among the anionically polymerizable active metals, alkali metals and alkaline earth metals are preferred, with alkali metals being more preferred. 【0084】As anionically polymerizable active metal compounds, organoalkali metal compounds are preferred. Examples of organoalkali metal compounds include organomonolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenithium; polyfunctional organolithium compounds such as dilythiomethane, dilythionaphthalene, 1,4-dilythiobutane, 1,4-dilythio-2-ethylcyclohexane, and 1,3,5-trilythiobenzene; and sodium naphthalene and potassium naphthalene. Among these organoalkali metal compounds, organolithium compounds are preferred, and organomonolithium compounds are more preferred. 【0085】 The amount of organoalkali metal compound used can be appropriately set according to the desired melt viscosity, molecular weight, etc., of the modified liquid diene polymer, but it is usually used in an amount of 0.01 to 3 parts by mass per 100 parts by mass of the total monomer. 【0086】 The above-mentioned organoalkali metal compounds can also be reacted with secondary amines such as dibutylamine, dihexylamine, and dibenzylamine to be used as organoalkali metal amides. 【0087】 Polar compounds are typically used in anionic polymerization to adjust the microstructure (e.g., vinyl content) of the unmodified liquid diene polymer without deactivating the reaction. Examples of polar compounds include ether compounds such as dibutyl ether, tetrahydrofuran, and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides; and phosphine compounds. Polar compounds are usually used in amounts of 0.01 to 1000 moles per mole of organoalkali metal compound. 【0088】 The temperature for solution polymerization is typically in the range of -80 to 150°C, preferably 0 to 100°C, and more preferably 10 to 90°C. The polymerization method may be batch or continuous. 【0089】Polymerization can be stopped by adding a polymerization inhibitor. Examples of polymerization inhibitors include alcohols such as methanol and isopropanol. The resulting polymerization reaction solution can be poured into a poor solvent such as methanol to precipitate the unmodified liquid diene polymer, or the polymerization reaction solution can be washed with water, separated, and dried to isolate the unmodified liquid diene polymer. 【0090】 The unmodified liquid diene polymer obtained in this way may be modified by reacting it directly (without hydrogenation) with a compound that gives a functional group represented by formula (I), or the unmodified liquid diene polymer obtained may be hydrogenated so that it has at least 10 mol% of 1,2-bonds, and then reacted with a compound that gives a functional group represented by formula (I) to perform the modification. 【0091】 Unmodified liquid diene polymers are preferably not modified with functional groups such as hydroxyl groups, in order to allow the properties of the modifying group represented by formula (I) to be exhibited in a more favorable state. The unmodified liquid diene polymer, being unmodified with other functional groups, tends to result in a more stable modified liquid diene polymer (B). Furthermore, the interaction (e.g., reactivity) of the functional group represented by formula (I) in the modified liquid diene polymer (B) with fillers (e.g., silica) tends to be more favorable. 【0092】 An unmodified liquid diene polymer, for example, formula (III-1): A silane-modified liquid diene polymer can be produced by reacting it with a silane compound represented by formula (III-1) and / or a disilane compound of a silane compound represented by formula (III-1), which is modified with a modifying group derived from the silane compound represented by formula (III-1). Alternatively, an unmodified liquid diene polymer may be reacted with one type of silane compound represented by formula (III-1) and / or a disilane compound of a silane compound represented by formula (III-1), or with two or more types of silane compounds represented by formula (III-1) and / or disilane compounds of silane compounds represented by formula (III-1). The disilane compound of the silane compound represented by formula (III-1) may have at least one mercapto group and at least one R６ And, R ７ , R ８ and R ９ Examples of disilane compounds include those having at least two selected from the group. For example, a disilane compound of the silane compound represented by formula (III-1) is formula (III-2): Examples of compounds represented by the formula are shown below. In the following, formulas (III-1) and (III-2) will be collectively referred to as formula (III). 【0093】 R in equation (III) ６ This refers to a divalent alkylene group having 1 to 6 carbon atoms. Examples of divalent alkylene groups having 1 to 6 carbon atoms include the methylene group, ethylene group, propylene group, butylene group, pentylene group, and hexylene group. 【0094】 R in equation (III) ７ , R ８ and R ９ Each of these independently represents a methoxy group, an ethoxy group, a phenoxy group, a methyl group, an ethyl group, or a phenyl group. However, R ７ , R ８ and R ９ At least one of them is a methoxy group, an ethoxy group, or a phenoxy group. 【0095】 Examples of silane compounds represented by the above formula (III-1) include mercaptomethylenemethyldiethoxysilane, mercaptomethylenetriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 2-mercaptoethylmethoxydimethylsilane, 2-mercaptoethylethoxydimethylsilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, 3-mercaptopropyldiethoxymethylsilane, 3-mercaptopropyldimethoxyethylsilane, 3-mercaptopropyldiethoxyethylsilane, 3-mercaptopropylmethoxydimethylsilane, and 3-mercaptopropylethoxydimethylsilane. These silane compounds may be used individually or in combination of two or more. 【0096】The mercapto group (-SH) of the silane compound represented by formula (III) undergoes a radical addition reaction with the carbon-carbon unsaturated bonds contained in the unmodified liquid diene block copolymer, thereby obtaining a silane-modified liquid diene polymer having a functional group derived from the silane compound represented by formula (III). It is presumed that during this radical addition reaction, the radical addition reaction preferentially occurs with the carbon-carbon unsaturated bonds contained in the 1,2-linked butadiene units contained in the unmodified liquid diene block polymer. As a result, a silane-modified liquid diene polymer is obtained in which the functional group derived from the silane compound is unevenly distributed at specific locations in the polymer chain. 【0097】 Next, to the silane-modified liquid diene polymer having a functional group derived from the obtained silane compound, formula (IV): [R １０ represents a divalent organic group containing O and C, and R １１ A modified liquid diene polymer (B) modified with the modifying group represented by formula (I) can be produced by reacting an amine compound represented by formula (IV), a diamine compound of the amine compound represented by formula (IV), and / or derivatives thereof. In the following, the amine compound represented by formula (IV) and the diamine compound of the amine compound will also be referred to as amine compound (IV). An unmodified liquid diene polymer may be reacted with one type of amine compound (IV) and / or a derivative thereof, or two or more types of amine compounds (IV) and / or derivatives thereof. The diamine compound of the amine compound represented by formula (IV) has at least one secondary or primary amino group and H-R １０ Examples include diamine compounds having -. For example, diamine compounds that are line-symmetric with respect to N-H in formula (IV) (e.g., (H-R １０ -) (R １１ -)N-N(-R １１ ) (-R １０ Compounds represented by -H), N-R in amine compounds (IV) １１ Diamine compounds that are symmetrical with respect to (H-R) １０ -)(H-)N-N(-H)(-R１０ Examples include -H). Further, as the diamine compound, a diamine compound having a substituent between two amino groups is also included. The substituent is at least one selected from the group consisting of an alkylene group having 1 to 12 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, a hydrocarbon group having 3 to 12 carbon atoms including an alicyclic structure having 3 to 12 carbon atoms, and a hydrocarbon group having 6 to 12 carbon atoms including an aromatic ring having 6 to 12 carbon atoms. For example, the diamine compound is ((R １３ )(R １３ ))N-R １４ -N(R １３ )(R １３ ))). In this formula, each R １３ may be the same as or different from each other, and may be -R １０ -H or -R １１ described above. Further, R １４ may be a single bond, or at least one selected from the group consisting of an alkylene group having 1 to 12 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, a hydrocarbon group having 3 to 12 carbon atoms including an alicyclic structure having 3 to 12 carbon atoms, and a hydrocarbon group having 6 to 12 carbon atoms including an aromatic ring having 6 to 12 carbon atoms. However, the diamine compound has at least one primary amino group and / or secondary amino group. Further, examples of these derivatives include an amine compound represented by formula (IV), or a salt or ester of the diamine compound. 【0098】 R １０ in formula (IV) represents a divalent organic group containing O and C. Examples of the divalent organic group containing O and C include a carbonyl group, a carboxyl group, an ester group, etc. R １０ is preferably a group in which at least one methylene group (-CH ２ -) contained in the divalent organic group is substituted with at least one group selected from the group consisting of -O-, -C(=O)-, -C(=O)-O-, and -O-C(=O)-, from the viewpoint of improving the dispersibility of the filler (C) and the vulcanization rate of the rubber composition. Specific examples of such a group include the groups exemplified above for R ３ in formula (I), and R３ A preferred group for this is R in formula (IV). １０ It is a favorable group for this purpose. 【0099】 R in equation (IV) １１ R represents a hydrogen atom or an alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but from the viewpoint of hydrolysis reactivity, the alkyl group is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably an alkyl group having 1 or 2 carbon atoms. １１ R is preferably a hydrogen atom or a C1 alkyl group. That is, R in formula (IV) １１ It is preferable that this is a hydrogen atom or a methyl group. 【0100】 The amine compound represented by the above formula (IV) is formula (V): [R １２ R represents at least one selected from the group consisting of alkylene groups having 1 to 12 carbon atoms, alkenylene groups having 2 to 12 carbon atoms, hydrocarbon groups having 3 to 12 carbon atoms including an alicyclic structure, and hydrocarbon groups having 6 to 12 carbon atoms including an aromatic ring. １１ Preferably, the compound is an amine compound and / or derivative thereof represented by [where represents a hydrogen atom or an alkyl group]. 【0101】 R in equation (V) １２ This represents at least one selected from the group consisting of alkylene groups having 1 to 12 carbon atoms, alkenylene groups having 2 to 12 carbon atoms, hydrocarbon groups having 3 to 12 carbon atoms including an alicyclic structure, and hydrocarbon groups having 6 to 12 carbon atoms including an aromatic ring. 【0102】 R in equation (V) １１ R in equation (IV) １１ This is synonymous with the preferred description, and the same applies to it. 【0103】Examples of amine compounds represented by formula (V) and their derivatives include aminoethanol, 2-aminoethanol, 3-aminopropanol, 4-aminobutanol, 5-aminopentanol, 6-aminohexanol, 7-aminoheptanol, 8-aminooctanol, 9-aminononanol, 10-aminodecanol, aminophenol, 4-amino-2-hydroxytoluene, 4-amino-3-hydroxytoluene, 4-amino-2-hydroxybenzoic acid, 4-amino-3-hydroxybenzoic acid, 4-amino-2-hydroxybenzaldehyde, and their derivatives. 【0104】 The method for adding the compound represented by formula (III) and the compound represented by formula (IV) to a liquid diene polymer is not particularly limited. For example, a method can be employed in which the compound represented by formula (III), and optionally a radical catalyst, are added to an unmodified liquid diene polymer, heated in or out of the presence of an organic solvent, and then the compound represented by formula (IV) is added and heated in or out of the presence of an organic solvent. There are no particular restrictions on the radical generator used, and commercially available organic peroxides, azo compounds, hydrogen peroxide, etc., can be used. Derivatives thereof may also be used as the compound represented by formula (III) and the compound represented by formula (IV). 【0105】Examples of the above organic peroxides include methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, and 2,2-bis(t-butylperoxy) Tan, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, 2,5-dimethylhexane 2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, bis(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxide) Oxy)hexane, 2,5-hexanoyl peroxide, lauroyl peroxide, succinic acid peroxide, benzoyl peroxide and its substituted derivatives, 2,4-dichlorobenzoyl peroxide, metatol oil peroxide, diisopropyl peroxydicarbonate, t-butyl-2-ethylhexanoate, di-2-ethylhexyl peroxydicarbonate, dimethoxyisopropyl peroxycarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, t-butyl Examples include peroxyacetate, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, t-butyl peroxyoctanoate, t-butyl peroxy 3,3,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxycarbonate, t-butyl peroxybenzoate, t-butyl peroxyisobutyrate, n-butyl-4,4-di(t-butylperoxy)valerate, and t-hexylperoxyisopropyl monocarbonate. 【0106】Examples of the above azo compounds include 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitride), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis(2-(2-imidazolin-2-yl)propane), 2,2'- Examples include azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropane), 2,2'-azobis(2-hydroxymethylpropionnitrile), 4,4'-azobis(4-cyanovaleric acid), dimethyl 2,2'-azobis(2-methylpropionate), 2-cyano-2-propylazoformamide, and 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile. 【0107】 The organic solvents used in the above method generally include hydrocarbon solvents and halogenated hydrocarbon solvents. Among these organic solvents, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene, and xylene are preferred. 【0108】 Furthermore, when carrying out the reaction to add the modified compound using the above method, an anti-aging agent may be added from the viewpoint of suppressing side reactions, etc. 【0109】Preferred anti-aging agents used at this time include, for example, 2,6-di-t-butyl-4-methylphenol (BHT), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol) (AO-40), and 3,9-bis[1,1-dimethyl-2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propyl Pionyloxyethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (AO-80), 2,4-bis[(octylthio)methyl]-6-methylphenol (Irganox 1520L), 2,4-bis[(dodecylthio)methyl]-6-methylphenol (Irganox 1726), 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate (Smilizer) GS), 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (Smilizer GM), 6-t-butyl-4-[3-(2,4,8,10-tetra-t-butyldibenzo[d,f][1,3,2]dioxaphosfepin-6-yloxy)propyl]-2-methylphenol (Smilizer GP), tris(2,4-di-t-butylphenyl) phosphite (Irgafos168), di Examples include octadecyl 3,3'-dithiobispropionate, hydroquinone, p-methoxyphenol, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (Nocrack 6C), bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (LA-77Y), N,N-dioctadecylhydroxylamine (Irgastab FS042), and bis(4-t-octylphenyl)amine (Irganox 5057). The above anti-aging agents may be used individually or in combination of two or more. 【0110】 The amount of antioxidant added is preferably 0 to 10 parts by mass, and more preferably 0 to 5 parts by mass, per 100 parts by mass of the unmodified liquid diene polymer. 【0111】In the modified liquid diene polymer (B), the functional group may be introduced at the polymerization end or at a side chain of the polymer chain, but it is preferable that it be at a side chain of the polymerization chain from the viewpoint that multiple functional groups can be easily introduced. Furthermore, the functional group may be included alone or in the form of two or more. Therefore, the modified liquid diene polymer (B) may be modified with one type of modifying compound or with two or more types of modifying compounds. 【0112】 The mixing ratio of the unmodified liquid diene polymer to the modified compound represented by formula (III) can be appropriately set, for example, so that the average number of functional groups per molecule of the modified liquid diene polymer reaches a desired value. However, it is preferable to mix them so that the mass ratio of the unmodified liquid diene polymer to the modified compound (e.g., compound (III)) (unmodified liquid diene polymer / modified compound) is 0.3 to 50. 【0113】 Next, the mixing ratio of the liquid diene polymer modified with the modified compound represented by formula (III) and the modified compound represented by formula (IV) can be appropriately set, for example, so that the average number of functional groups per molecule of the modified liquid diene polymer is a desired value. For example, the mass ratio (liquid diene polymer / modified compound) of the modified liquid diene polymer to the modified compound (e.g., compound (IV)) is preferably 0.3 to 50, more preferably 0.5 to 30, even more preferably 1 to 20, even more preferably 1 to 15, even more preferably 1 to 12, and most preferably 1 to 6. 【0114】 From the viewpoint of adjusting the melt viscosity, molecular weight distribution (Mw / Mn), etc., of the liquid diene polymer to within the above range, it is preferable to add a radical catalyst during the modification reaction and to carry out the reaction at a low temperature and for a short time. 【0115】(Filler (C)) The rubber composition of this disclosure contains at least one filler (C). Examples of fillers (C) include inorganic fillers such as carbon black, silica, clay, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, titanium dioxide, glass fibers, fibrous fillers, and glass balloons; and organic fillers such as resin particles, wood powder, and cork powder. The inclusion of such fillers in the rubber composition can improve physical properties such as mechanical strength, heat resistance, or weather resistance, adjust hardness, and increase the amount of rubber. From the viewpoint of improving physical properties such as mechanical strength or rigidity, and improving wet grip and ice grip, carbon black and silica are preferred among the above fillers (C). These fillers (C) may be used individually or in combination of two or more. 【0116】 Examples of carbon black (hereinafter also referred to as "CB") include furnace black, channel black, thermal black, acetylene black, and Ketjen black. From the viewpoint of improving crosslinking speed and mechanical strength, furnace black is preferred among these carbon blacks. These carbon blacks may be used individually or in combination of two or more types. 【0117】 The average particle size of carbon black is preferably 5 to 100 nm, more preferably 5 to 80 nm, and even more preferably 5 to 70 nm, from the viewpoint of improving dispersibility, mechanical strength, and hardness. The average particle size of carbon black can be determined by measuring the diameter of the particles using a transmission electron microscope and calculating the average value. 【0118】 Examples of commercially available furnace black include Mitsubishi Chemical Corporation's "Dia Black" and Tokai Carbon Co., Ltd.'s "Seasto." Examples of commercially available acetylene black include Denki Kagaku Kogyo Co., Ltd.'s "Denka Black." Examples of commercially available Ketjen black include Lion Corporation's "ECP600JD." 【0119】Carbon black may be subjected to acid treatment with nitric acid, sulfuric acid, hydrochloric acid, or a mixture thereof, or surface oxidation treatment by heat treatment in the presence of air, from the viewpoint of improving wettability and dispersibility with solid rubber (A). Furthermore, from the viewpoint of improving the mechanical strength of the rubber composition of this disclosure and the crosslinked product obtained from this composition, heat treatment may be performed at 2,000 to 3,000°C in the presence of a graphitization catalyst. The graphitization catalyst may be boron, boron oxide (for example, B ２ O ２ , B ２ O ３ , B ４ O ３ , B ４ O ５ (e.g.), boron oxoacids (e.g., orthoboric acid, metaboric acid, tetraboric acid, etc.) and their salts, boron carbides (e.g., B ４ C, B ６ C, boron nitride (BN), and other boron compounds are preferably used. 【0120】 Carbon black can also be used after adjusting its particle size through grinding or other methods. High-speed rotary grinders (hammer mills, pin mills, cage mills), various ball mills (rolling mills, vibrating mills, planetary mills), and agitation mills (bead mills, attritors, flow-through mills, annular mills) can be used to grind carbon black. 【0121】 Examples of silica include wet silica (hydrated silica), dry silica (anhydrous silica), calcium silicate, and aluminum silicate. Among these silicas, wet silica is preferred from the viewpoint of further improving processability, mechanical strength, and wear resistance. These silicas may be used individually or in combination of two or more types. 【0122】 The average particle size of silica is preferably 0.5 to 200 nm, more preferably 5 to 150 nm, and even more preferably 10 to 100 nm, from the viewpoint of improving processability, rolling resistance, mechanical strength, and wear resistance. The average particle size of silica can be determined by measuring the diameter of the particles using a transmission electron microscope and calculating the average value. 【0123】From the viewpoint of improving the rolling resistance performance of the rubber composition and its crosslinked product, the rubber composition preferably contains carbon black and / or silica as filler (C), and more preferably silica. Furthermore, the rubber composition preferably contains carbon black with an average particle size of 5 to 100 nm and / or silica with an average particle size of 0.5 to 200 nm. 【0124】 In a rubber composition according to a preferred embodiment of the present disclosure, the content of filler (C) per 100 parts by mass of solid rubber (A) is 30 to 150 parts by mass. If the content of filler (C) is less than 30% by mass, the abrasion resistance of the rubber composition may be impaired, and if it exceeds 150% by mass, the grip of the rubber composition may decrease. The content of filler (C) is preferably 33 to 140 parts by mass, more preferably 35 to 130 parts by mass, and even more preferably 40 to 120 parts by mass. When the content of filler (C) is within the above range, processability, rolling resistance performance, mechanical strength, and abrasion resistance are improved. 【0125】 The amount of fillers other than silica and carbon black in filler (C) is not particularly limited, but may be, for example, 0 to 120 parts by mass per 100 parts by mass of solid rubber (A), preferably 0 to 90 parts by mass, more preferably 0 to 80 parts by mass, and even more preferably 0 to 70 parts by mass. 【0126】 From the viewpoint of the stability of the rubber composition, the total mass of the solid rubber (A), modified liquid diene polymer (B), and filler (C) contained in the rubber composition is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 85 to 100% by mass, relative to the total amount of the rubber composition. 【0127】In addition to a solid rubber (A), a modified liquid diene polymer (B), and a filler (C), the rubber composition may further contain a crosslinking agent (D) for crosslinking the rubber. Examples of crosslinking agents (D) include sulfur, sulfur compounds, oxygen, organic peroxides, phenolic resins, amino resins, quinones and quinone dioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides and organometallic halides, and silane compounds. Examples of sulfur compounds include morpholine disulfide and alkylphenol disulfide. Examples of organic peroxides include cyclohexanone peroxide, methyl acetacetate peroxide, t-butyl peroxyisobutyrate, t-butyl peroxybenzoate, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, dit-butyl peroxide, and 1,3-bis(t-butylperoxyisopropyl)benzene. These crosslinking agents (D) may be used individually or in combination of two or more. From the viewpoint of the mechanical properties of the crosslinked product, the above crosslinking agent (D) is preferably contained in an amount of 0.1 to 10 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.8 to 5 parts by mass, per 100 parts by mass of solid rubber (A). 【0128】 The rubber composition may also contain a vulcanization accelerator (E) if it contains, for example, sulfur, sulfur compounds, etc., as a crosslinking agent (D) for crosslinking (vulcanizing) the rubber. Examples of vulcanization accelerators (E) include guanidine compounds, sulfenamide compounds, thiazole compounds, thiram compounds, thiourea compounds, dithiocarbamate compounds, aldehyde-amine compounds, aldehyde-ammonia compounds, imidazoline compounds, and xanthate compounds. These vulcanization accelerators (E) may be used individually or in combination of two or more. The above vulcanization accelerator (E) is preferably contained in an amount of 0.1 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of solid rubber (A). 【0129】If the rubber composition contains, for example, sulfur, sulfur compounds, etc., as a crosslinking agent (D) for crosslinking (vulcanizing) the rubber, the rubber composition may further contain a vulcanization aid (F). Examples of vulcanization aids (F) include fatty acids such as stearic acid, metal oxides such as zinc oxide, and fatty acid metal salts such as zinc stearate. These vulcanization aids (F) may be used individually or in combination of two or more. The amount of the vulcanization aid (F) is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of solid rubber (A). 【0130】 If the rubber composition contains silica as filler (C), it is preferable that the rubber composition further contains a silane coupling agent. Examples of silane coupling agents include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidoxy compounds, nitro compounds, chloro compounds, and the like. 【0131】 Examples of sulfide compounds include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, and 3-trimethoxysilylpropyl-N,N-dimethyl Examples include luthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, and 3-octanoylthio-1-propyltriethoxysilane. 【0132】Examples of mercapto compounds include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane. 【0133】 Examples of vinyl compounds include vinyltriethoxysilane and vinyltrimethoxysilane. 【0134】 Examples of amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane. 【0135】 Examples of glycidoxy compounds include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane. 【0136】 Examples of nitro compounds include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane. 【0137】 Examples of chloro compounds include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane. 【0138】 Other compounds include, for example, octyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and hexadecyltrimethoxysilane. 【0139】These silane coupling agents may be used individually or in combination of two or more. Among these silane coupling agents, bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide, and 3-mercaptopropyltrimethoxysilane are preferred from the viewpoint of significant additive effect and cost. 【0140】 The amount of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 15 parts by mass, per 100 parts by mass of silica. When the silane coupling agent content is within the above range, dispersibility, coupling effect, reinforcing properties, and wear resistance are improved. 【0141】 A rubber composition according to a preferred embodiment of the present disclosure comprises at least one resin. The resin may be a synthetic resin or a natural resin. These resins may be used individually or in combination of two or more. 【0142】 Examples of synthetic resins include petroleum-based resins, and oligomers obtained by polymerizing raw materials consisting of a C5 fraction, a C9 fraction, a purified component of the C5 fraction, a purified component of the C9 fraction, or a mixture of these fractions or purified components can be used. Furthermore, oligomers obtained in this manner that have been modified by hydrogenation or other means can also be used. Examples of C5 fractions include cyclopentadiene, dicyclopentadiene, isoprene, 1,3-pentadiene, 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene, 2-pentene, and cyclopentene. Examples of C9 fractions include styrene, allylbenzene, α-methylstyrene, vinyltoluene, β-methylstyrene, and indene. Other materials such as alkylphenol resins and xylene resins can also be used. 【0143】As natural resins, rosin-based resins or terpene-based resins can be used. Rosin-based resins are resins obtained from pine, and their main component is a mixture of abietic acid and its isomers. Modified rosin-based resins such as esterification, polymerization, and hydrogenation are also included. Unmodified rosin-based resins include tall rosin, gum rosin, and wood rosin. Polymerized rosin, disproportionated rosin, hydrogenated rosin, maleic acid-modified rosin, fumaric acid-modified rosin, and modified versions thereof through esterification and hydrogenation are also included. Terpene-based resins are oligomers obtained by polymerizing raw materials containing terpene monomers. Modified oligomers such as hydrogenation are also included. Examples of terpene monomers include α-pinene, β-pinene, dipentene, limonene, myrcene, allocimene, ocimene, α-ferlandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, sabinene, paramentadienes, and carenes, which have monoterpenes, sesquiterpenes, diterpenes, etc. as their basic skeletons. In addition, benzofurans (C) that can copolymerize with terpene monomers are also included. ８ H ６ The oligomer may contain coumarone monomers such as O), vinyl aromatic compounds, phenolic monomers, etc., and may also include oligomers obtained by hydrogenation or other modifications. 【0144】 The amount of resin in the above rubber composition is preferably 0 to 400 parts by mass, more preferably 0 to 200 parts by mass, and even more preferably 0 to 150 parts by mass, per 100 parts by mass of solid rubber. When the rubber composition contains resin, it is possible to impart tackiness to the rubber composition, improve processability, and enhance the slipperiness of the rubber. 【0145】The rubber composition may contain, as necessary, process oils such as silicone oil, aroma oil, TDAE (Treated Distilled Aromatic Extracts), MES (Mild Extracted Solvates), RAE (Residual Aromatic Extracts), paraffin oil, naphthenic oil, and resin components such as coumarone-indene resins as softeners, to the extent that they do not impede the effects of the present disclosure, for the purpose of improving processability, fluidity, etc. If the rubber composition contains the above process oils as softeners, the amount is preferably less than 50 parts by mass per 100 parts by mass of solid rubber (A). 【0146】 The rubber composition may contain additives such as antioxidants, waxes, antioxidants, lubricants, light stabilizers, scorch inhibitors, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, mold release agents, foaming agents, antibacterial agents, antifungal agents, and fragrances, as needed, to improve weather resistance, heat resistance, oxidation resistance, etc., to the extent that they do not impair the effects of the disclosed invention. Examples of antioxidants include hindered phenol compounds, phosphorus compounds, lactone compounds, and hydroxyl compounds. Examples of antioxidants include amine-ketone compounds, imidazole compounds, amine compounds, phenol compounds, sulfur compounds, and phosphorus compounds. These additives may be used individually or in combination of two or more. 【0147】 (Method for Manufacturing Rubber Composition) The method for manufacturing the rubber composition is not particularly limited as long as the above components can be mixed uniformly. Examples of equipment used in manufacturing the rubber composition include tangential or meshing type closed-type kneaders such as kneader-ruders, brabenders, Banbury mixers, and internal mixers, as well as single-screw extruders, twin-screw extruders, mixing rolls, and rollers. The above rubber composition can usually be manufactured in a temperature range of 70 to 270°C. 【0148】(Crosslinked material) A crosslinked material can be obtained by crosslinking the above rubber composition. The crosslinking conditions for the rubber composition can be set appropriately depending on its intended use. For example, when using sulfur or a sulfur compound as a crosslinking agent and crosslinking (vulcanizing) the rubber composition using a mold, the crosslinking temperature is usually 120 to 200°C and the pressurizing conditions are usually 0.5 to 2.0 MPa, allowing for crosslinking (vulcanization). 【0149】 The extraction rate of the modified liquid diene polymer (B) from the crosslinked material is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. The above extraction rate can be calculated from the amount of modified liquid diene polymer (B) extracted into toluene after immersing 2 g of the crosslinked material in 400 mL of toluene and refrigerating it at 23°C for 48 hours. 【0150】 The above-mentioned rubber composition and crosslinked product thereof can also be used as at least part of a tire. The tire thus obtained has excellent rolling resistance, good wear resistance, and excellent grip (wet grip and / or ice grip) because the dispersion state of the filler (C) is ideal (for example, the pain effect is sufficiently reduced). Furthermore, in a preferred embodiment of this disclosure, the bleed-out of the modified liquid diene polymer can be suppressed, resulting in excellent stability. Therefore, this disclosure also relates to a tire rubber composition including the rubber composition of this disclosure described above and / or a crosslinked product thereof. 【0151】 Examples of tire parts in which the above-mentioned rubber composition and crosslinked products of the rubber composition can be used include the tread (cap tread, under tread), sidewall, run-flat tire rubber reinforcement layer (liner, etc.), rim cushion, bead filler, bead insulation, bead apex, clinch apex, belt, belt cushion, breaker, breaker cushion, chafer, chafer pad, strip apex, and the like. 【0152】Examples of tires that can use the above-mentioned rubber composition and its crosslinked counterpart include pneumatic tires and non-pneumatic tires. Among these, pneumatic tires are preferred. For example, they can be suitably used as summer tires and winter tires (studless tires, snow tires, studless tires, etc.). The tires can be used for passenger car tires, large passenger car tires, large SUV tires, heavy-duty tires for trucks and buses, light truck tires, motorcycle tires, run-flat tires, and racing tires (high-performance tires). 【0153】 The above-mentioned rubber composition and its crosslinked material can be used for purposes other than tires, such as packing, sheet materials, hoses, belts, rubberized fabrics, footwear, and adhesives. 【0154】 The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. 【0155】 The methods for measuring the physical properties of unmodified liquid diene polymers and modified liquid diene polymers are as follows. 【0156】 <Weight-average molecular weight, number-average molecular weight, and molecular weight distribution> The weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the modified liquid diene polymer were determined by GPC (gel permeation chromatography) using standard polystyrene-based molecular weight. The measurement equipment and conditions were as follows: • Equipment: Tosoh Corporation GPC instrument "HLC-8320GPC" • Separation column: Tosoh Corporation "TSKgelSuperHZ4000 x 2" • Eluent: Tetrahydrofuran • Eluent flow rate: 0.35 mL / min • Sample concentration: 5 mg / 10 mL • Column temperature: 40°C 【0157】 <Amount of cis-1,4-bonding units and trans-1,4-bonding units> 30 mg of each modified liquid diene polymer was dissolved in 10 mL of carbon disulfide and measured using a Fourier transform infrared spectrophotometer (FT-IR). The absorbance peak absorbance (A) derived from the detected 1,2-bonding units was measured. Ｖ), absorption peak absorbance derived from cis-1,4-bond (A Ｃ ), Absorption peak absorbance derived from trans-1,4-bonds (A Ｔ The composition ratio was determined using formula (i) from the absorption coefficients of ), and Morero. Formula (i): cis-1,4-bond (C) ... 1.7455 * A Ｃ -0.0151*A Ｖ Trans-1,4-coupled (T) ... 0.4292 * A Ｔ -0.0129*A Ｖ -0.0454*A Ｃ 1.2-Bond (V)...0.3746*A Ｖ -0.007*A Ｃ Percentage of cis-1,4- bonds (%) = C / (C + V + T) * 100 Percentage of trans-1,4- bonds (%) = T / (C + V + T) * 100 Percentage of 1,2- bonds (%) = V / (C + V + T) * 100 【0158】 <Average number of modifying groups represented by formula (I) per molecule> The average number of modifying groups represented by formula (I) per molecule (average number of functional groups) of each diene polymer shown in the examples was calculated by the following method. Samples were prepared by dissolving 50 mg of each unmodified liquid diene polymer, modified liquid diene polymer, and amine-modified liquid diene polymer in 1 mL of deuterated chloroform, and were manufactured by JEOL Ltd. １ Measurements were performed using 1H-NMR (400 MHz). The average number of graft silane moieties per molecule of the modified liquid diene polymer was determined from the ratio of the peak integral value originating from the graft silane moieties of the modified liquid diene polymer to the peak integral value originating from the main chain of the liquid diene polymer. Furthermore, the average number of amino groups per graft silane moiety was determined from the integral ratio of the peak originating from the graft silane moieties of the modified liquid diene polymer and the peak originating from the amine-modified moieties of the obtained amine-modified liquid diene polymer. The average number of modifying groups (groups / polymer) represented by formula (I) per molecule of the amine-modified liquid diene polymer was then determined from the product of this average number and the average number of graft silane moieties per molecule of the modified liquid diene polymer. 【0159】<Method for measuring melt viscosity at 38°C> The melt viscosity of modified liquid diene rubber (B) at 38°C was measured using a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS.INC.). 【0160】 <Glass Transition Temperature (Tg)> 10 mg of the liquid diene rubber to be measured was placed in an aluminum pan, and a thermogram was measured by differential scanning calorimetry (DSC) at a heating rate of 10°C / min. The peak value of the DDSC was defined as the glass transition temperature. 【0161】 <Production Example 1: Production of Liquid Diene Polymer (A)> A thoroughly dried 3 L autoclave was purged with nitrogen, and 510 g of cyclohexane and 85 g of n-butyllithium (17% by mass hexane solution) were charged. After raising the temperature to 50°C, 5 g of N,N,N',N'-tetramethylethylenediamine was added, and 1270 g of butadiene was added sequentially under stirring conditions while controlling the polymerization temperature to 50°C to carry out polymerization. Methanol was then added to stop the polymerization reaction and obtain a polymer solution. Water was added to the obtained polymer solution and stirred, and the polymer solution was washed with water. After stopping the stirring, it was confirmed that the polymer solution phase and the aqueous phase had separated, and then the water was separated. The polymer solution after washing was vacuum dried at 70°C for 24 hours to obtain a liquid diene polymer (A) consisting of a butadiene homopolymer. 【0162】 <Production Example 2: Production of Liquid Diene Polymer (B)> A thoroughly dried 3 L autoclave was purged with nitrogen, and 170 g of hexane and 171 g of n-butyllithium (17% by mass hexane solution) were charged. 1250 g of butadiene was added sequentially under stirring conditions while controlling the polymerization temperature to 70°C to carry out polymerization. Methanol was then added to stop the polymerization reaction and obtain a polymer solution. Water was added to the obtained polymer solution and stirred, and the polymer solution was washed with water. After stopping the stirring and confirming that the polymer solution phase and the aqueous phase had separated, the water was separated. The polymer solution after washing was vacuum-dried at 70°C for 24 hours to obtain a liquid diene polymer (B) consisting of a butadiene homopolymer. 【0163】<Production Example 3: Production of Silane-Modified Liquid Diene Polymer (A1)> A 1 L autoclave was thoroughly dried and purged with nitrogen. 700 g of the unmodified liquid diene polymer from Production Example 1 was charged in, and nitrogen degassing was carried out at 60°C for 3 hours while stirring. 0.2 g of 1,1-bis(t-hexylperoxy)cyclohexane and 130 g of (3-mercaptopropyl)triethoxysilane were added, and the mixture was reacted at 105°C for 8 hours to obtain silane-modified liquid diene polymer (A1). 【0164】 <Production Example 4: Production of Silane-Modified Liquid Diene Polymer (B1)> A 1 L autoclave was thoroughly dried and purged with nitrogen. 600 g of the unmodified liquid diene polymer from Production Example 2 was charged in, and nitrogen degassing was carried out at 60°C for 3 hours while stirring. 0.8 g of 1,1-bis(t-hexylperoxy)cyclohexane and 102 g of (3-mercaptopropyl)triethoxysilane were added, and the mixture was reacted at 105°C for 8 hours to obtain silane-modified liquid diene polymer (B1). 【0165】 <Production Example 5: Production of Silane-Modified Liquid Diene Polymer (C1)> A 5 ​​L autoclave, thoroughly dried, was purged with nitrogen, and 1590 g of cyclohexane and 260 g of sec-butyllithium (10.5% by mass cyclohexane solution) were charged. 218 g of butadiene was added under stirring conditions while controlling the polymerization temperature to 50°C, and polymerization was carried out. Next, 763 g of isoprene was added sequentially and polymerization was carried out, followed by the addition of 246 g of butadiene and further polymerization. Methanol was then added to stop the polymerization reaction, and a polymer solution was obtained. Water was added to the obtained polymer solution and stirred, and the polymer solution was washed with water. After stopping the stirring, it was confirmed that the polymer solution phase and the aqueous phase had separated, and then the water was separated. The polymer solution after washing was vacuum-dried at 70°C for 24 hours to obtain the unliquid diene copolymer (C). Furthermore, 21 g of 1,1-bis(t-hexylperoxy)cyclohexane and 334 g of (3-mercaptopropyl)triethoxysilane were added and reacted at 110°C for 8 hours to obtain a silane-modified liquid diene polymer (C1). 【0166】<Production Example 6: Production of Modified Liquid Diene Polymer (I)-1> A 1 L autoclave that was thoroughly dried was purged with nitrogen, and 600 g of the silane-modified liquid diene polymer (A1) from Production Example 3 was charged in. The mixture was degassed with nitrogen while stirring at 80°C for 3 hours. 26.1 g of 2-aminoethanol was added, and the mixture was reacted at 140°C for 4 hours to obtain Modified Liquid Diene Polymer (I)-1. 【0167】 <Production Example 7: Production of Modified Liquid Diene Polymer (I)-2> A 1 L autoclave was thoroughly dried and purged with nitrogen. 602 g of the silane-modified liquid diene polymer (B1) from Production Example 4 was charged in, and nitrogen degassing was carried out while stirring at 80°C for 3 hours. 24 g of 3-aminoethanol was added, and the mixture was reacted at 140°C for 4 hours to obtain Modified Liquid Diene Polymer (I)-2. 【0168】 <Production Example 8: Production of Modified Liquid Diene Polymer (I)-3> A 1 L autoclave was thoroughly dried and purged with nitrogen. 450 g of the silane-modified liquid diene polymer (A1) from Production Example 3 was charged in, and nitrogen degassing was carried out while stirring at 60°C for 5 hours. 23.9 g of 3-amino-1-propanol and 67 g of 3-ethyl-3-pentanol were added, and the mixture was reacted at 125°C for 5 hours, followed by a further reaction at 150°C for 3 hours to obtain Modified Liquid Diene Polymer (I)-3. 【0169】 <Production Example 9: Production of Modified Liquid Diene Polymer (I)-4> A 1 L autoclave that was thoroughly dried was purged with nitrogen, and 450 g of the silane-modified liquid diene polymer (C1) from Production Example 5 was charged in. The mixture was degassed with nitrogen while stirring at 60°C for 3 hours. 21.6 g of 3-amino-1-propanol was added, and the mixture was reacted at 150°C for 5 hours to obtain Modified Liquid Diene Polymer (I)-4. 【0170】 The physical properties of the liquid diene polymers obtained in Production Examples 1 to 9 were measured according to the method described above. The results are shown in Table 1. 【0171】 【0172】The components used in the examples and comparative examples are shown below. <Solid rubber> Solution-polymerized styrene-butadiene rubber: HPR355 (manufactured by ENEOS Material JSR Corporation, with alkoxysilyl groups introduced at the ends, styrene content 28% by mass, vinyl content 56% by mass, glass transition temperature -24°C) STR20: Natural rubber butadiene rubber from Thailand: BR01 (manufactured by ENEOS Material JSR Corporation, cis isomer content 95% by mass, weight-average molecular weight 550,000) 【0173】 <Silica / Silane Coupling Agent> Silica: ULTRASIL7000GR (manufactured by Evonik Degussa Japan, wet-processed silica, average particle size 14 nm) Silane coupling agent: Si-75 (manufactured by Evonik Degussa Japan) <Carbon Black (CB)> N330: Dia Black H (manufactured by Mitsubishi Chemical Corporation) 【0174】 <Plasticizer> TDAE: VivaTec500 (manufactured by H&R) <Optional components> Zinc oxide: ZnO (manufactured by Sakai Chemical Industry Co., Ltd.) Stearic acid: Lunac S-20 (manufactured by Kao Corporation) Wax: Santite S (manufactured by Seiko Chemical Co., Ltd.) Anti-aging agent: Nolac 6C (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanizing agent Mucron (OT-20): Insoluble sulfur Mucron OT-20 (manufactured by Shikoku Chemicals Co., Ltd.) Vulcanization accelerator 1: Noxellar CZ (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) Vulcanization accelerator 2: Noxellar D (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) 【0175】<Examples and Comparative Examples: Production of Rubber Compositions> Solid rubber, liquid diene polymer, filler, plasticizer, silane coupling agent, zinc oxide, stearic acid, wax, and antioxidant were each placed in a sealed Banbury mixer according to the mixing ratios (parts by mass) listed in Tables 2 and 3. The mixture was kneaded for 6 to 8 minutes to reach a starting temperature of 60°C and a resin temperature of 145 to 160°C, then removed from the mixer and cooled to room temperature. Next, this mixture was placed back into the sealed Banbury mixer and kneaded for 4 to 6 minutes to reach a starting temperature of 90°C and a resin temperature of 150°C, then removed from the mixer and cooled to room temperature. The resulting mixture was then placed back into the Banbury mixer, a vulcanizing agent and a vulcanization accelerator were added, and the mixture was kneaded for 75 seconds to reach a starting temperature of 50°C and a target temperature of 75 to 95°C to obtain a rubber composition. The obtained rubber composition was press-molded (150-170°C, 30-50 minutes) to produce a vulcanized rubber sheet (2 mm thick) with a vulcanization rate of 90%, and used for various measurements. 【0176】 <Method for measuring vulcanization time> In accordance with JIS K 6300-2:2001, the torque of the rubber composition at 180°C was measured using a vibrating vulcanization tester (curastometer), and the time required to reach 90% vulcanization was recorded. The reciprocal of this time was used for evaluation. The results are shown as relative values ​​with Comparative Example 1 set to 100 for Comparative Example 2 and Example 1, Comparative Example 3 set to 100 for Comparative Example 4 and Example 2, Comparative Example 5 set to 100 for Comparative Example 6 and Example 3, and Comparative Example 7 set to 100 for Comparative Example 8 and Example 4. For Examples 5 to 8, the results are shown as relative values ​​with Comparative Examples 9 to 12 set to 100. A larger numerical value indicates that the rubber composition vulcanizes more quickly. 【0177】<Method for Measuring Rubber Hardness> Test pieces measuring 40 mm (length) x 5 mm (width) x 2 mm (thickness) were cut from the vulcanized rubber sheets of the rubber compositions prepared in the examples and comparative examples, and the rubber hardness was measured using a Type A hardness tester, referring to JIS K6253:2012. The results are shown as relative values ​​with Comparative Example 1 set as 100 for Comparative Example 2 and Example 1, Comparative Example 3 set as 100 for Comparative Example 4 and Example 2, Comparative Example 5 set as 100 for Comparative Example 6 and Example 3, and Comparative Example 7 set as 100 for Comparative Example 8 and Example 4. For Examples 5 to 8, the results are shown as relative values ​​with Comparative Examples 9 to 12 set as 100. A higher numerical value indicates higher hardness. 【0178】<Evaluation Method for Crosslinking Properties and Bleed-Out Inhibition Effect> Three circular test pieces, Φ32 mm in diameter and 2 mm thick, were punched out from the vulcanized rubber sheets of the rubber compositions prepared in the examples and comparative examples, and their weight (m1) and volume (v1) were measured. Sufficient volume of toluene was prepared to completely immerse the test pieces, and the entire test piece was immersed in toluene at room temperature for 48 hours. After that, the test pieces were removed and dried in a vacuum dryer at 80°C for 12 hours, and the weight (m2) and volume (v2) of the dried test pieces were measured. The above measurements were performed for all three test pieces. The obtained volumes (v1, v2) were substituted into formula (i) to determine the swelling rate, and the average value of the three was calculated. The reciprocal of this average swelling rate was used for evaluation. Formula (i) Swelling rate (%) = (v2 - v1) / v1 * 100 The results are shown as relative values ​​with Comparative Example 1 set to 100 for Comparative Example 2 and Example 1, Comparative Example 3 set to 100 for Comparative Example 4 and Example 2, Comparative Example 5 set to 100 for Comparative Example 6 and Example 3, and Comparative Example 7 set to 100 for Comparative Example 8 and Example 4. For Examples 5 to 8, the results are shown as relative values ​​with Comparative Examples 9 to 12 set to 100. A higher value indicates less swelling and higher crosslinking ability. In addition, the obtained weights (m1, m2) were substituted into formula (ii) to find each extraction rate, and the average of the three was calculated. The reciprocal of this average extraction rate was used for evaluation. Formula (ii): Extraction rate (%) = (m1 - m2) / m1 * 100 To confirm the effect of bleed-out suppression by the modified liquid diene polymer, the reciprocal of the extraction rate in the examples and comparative examples was calculated. For Comparative Example 2 and Example 1, the extraction rate of Comparative Example 1 was set to 100. For Comparative Example 4 and Example 2, the extraction rate of Comparative Example 3 was set to 100. For Comparative Example 6 and Example 3, the extraction rate of Comparative Example 5 was set to 100. For Comparative Example 8 and Example 4, the relative value of the reciprocal of the extraction rate when the reciprocal of the extraction rate of Comparative Example 7 was set to 100 was used as the bleed-out suppression effect. For Examples 5 to 8, the relative value of the reciprocal of the extraction rate when the reciprocal of the extraction rate of Comparative Examples 9 to 12 was set to 100 was used. A higher value indicates less extract and a higher bleed-out suppression effect. 【0179】<Method for Evaluating Stiffness> Test pieces measuring 40 mm in length, 5 mm in width, and 2 mm in thickness were cut from the vulcanized rubber sheets of the rubber compositions prepared in the examples and comparative examples. Using a dynamic viscoelasticity measuring device manufactured by GABO, the E' (storage modulus) was measured under the conditions of a measurement temperature of 60°C, a frequency of 10 Hz, a static strain of 10%, and a dynamic strain of 2%, and this was used as an index of stiffness. The results are shown as relative values ​​with Comparative Example 1 set to 100 for Comparative Example 2 and Example 1, Comparative Example 3 set to 100 for Comparative Example 4 and Example 2, Comparative Example 5 set to 100 for Comparative Example 6 and Example 3, and Comparative Example 7 set to 100 for Comparative Example 8 and Example 4. For Examples 5 to 8, the results are shown as relative values ​​with Comparative Examples 9 to 12 set to 100. A higher numerical value indicates higher stiffness. 【0180】 <Bonding strength with carbon black (CB)> Approximately 1 g each of the rubber compositions of the examples and comparative examples was cut into pieces, and the weight (W1) of the obtained pieces was measured. The weight (W2) of these pieces was measured again with the pieces placed in a wire mesh (200 mesh) basket, and the weight of the wire mesh basket (Wb) was obtained by subtracting W1 from W2. Next, the wire mesh containing the pieces was immersed in 200 ml of toluene and left to stand at room temperature for 72 hours. After that, the wire mesh basket containing the pieces was removed from the toluene, the solvent-insoluble components were air-dried at room temperature for 24 hours, and then dried under reduced pressure at 40°C for 12 hours to measure the total weight (W3). The obtained weights (W1, Wb, W3) were substituted into formula (iii) to determine the amount of bound rubber (%). Formula (iii) Bound rubber amount (%) = {(W3 - Wb) - (W1 * C / D)} / (W1 * E / D) * 100 C: Total weight of toluene-insoluble components in the rubber composition (filler and zinc oxide in this evaluation) D: Weight of the rubber composition E: Weight of solid rubber in the rubber composition The results for Comparative Example 6 and Example 3 are shown as relative values ​​with Comparative Example 5 set to 100. For Examples 7 and 8, the results are shown as relative values ​​with Comparative Examples 11 and 12 set to 100. A higher value indicates a larger amount of bound rubber, and that more liquid diene polymer components and carbon black are bonded together. 【0181】<Ice Grip Performance> Cylindrical friction coefficient test pieces (16 mm wide, 80 mm in diameter) were prepared from the rubber vulcanized sheets of the rubber compositions prepared in the examples and comparative examples. The friction coefficient on ice was measured under the following conditions, and the maximum value of the obtained friction coefficient was used as the index. The results are relative values, with Comparative Example 1 set to 100 for Example 1 and Comparative Example 2, Comparative Example 3 for Example 2 and Comparative Example 4, Comparative Example 5 for Example 3 and Comparative Example 6, and Comparative Example 7 for Example 4 and Comparative Example 8. A higher value indicates better ice grip performance of the rubber composition. [Measurement Equipment and Measurement Conditions] ・Equipment: RTM friction tester manufactured by Ueshima Seisakusho Co., Ltd. ・Measurement temperature: -10℃ ・Road surface: Ice ・Speed: 30 km / hrs ・Load: 50 N ・Slip ratio: 0-40% 【0182】 【0183】 【0184】 As shown in Tables 2 and 3, the rubber composition of this disclosure showed a shorter vulcanization time compared to rubber compositions containing an unmodified diene polymer of similar molecular weight and a similar amount of filler, and rubber compositions containing a diene polymer modified with a silane coupling agent of similar molecular weight and a similar amount of filler. Furthermore, compared to compositions containing an unmodified diene polymer, improvements in rubber hardness and rigidity were obtained, which is thought to indicate improved filler dispersibility. In addition, the rubber composition of this disclosure also showed a bleed-out suppression effect. Moreover, it exhibited ice grip properties equivalent to or better than rubber compositions containing a modified diene polymer that is modified with a silane coupling agent but does not have amino groups.

Claims

1. Solid rubber (A) 100 parts by mass, formula (I): [In the formula, X represents N, O, or S, and R １ represents a divalent hydrocarbon group, R ２ R represents a monovalent hydrocarbon group. ３ represents a divalent organic group containing O and C, and R ４ A rubber composition comprising 5 to 30 parts by mass of a modified liquid diene polymer (B) having a modified group represented by [where is a hydrogen atom or alkyl group, m is an integer from 0 to 2, n is an integer from 1 to 3, where m + n = 3, and * represents a bond], and 30 to 150 parts by mass of a filler (C).

2. R in equation (I) ３ This is a divalent organic group containing at least one methylene group (-CH ２ The rubber composition according to claim 1, wherein -) represents a group substituted with at least one group selected from the group consisting of -O-, -C(=O)-, -C(=O)-O-, and -O-C(=O)-.

3. The modified group represented by the formula (I) is the formula (II): [In the formula, R １ , R ２ , R ４ , m, n, and * are the same as R １ , R ２ , R ４ , m, n, and * in the formula (I), and R ５ represents at least one selected from the group consisting of an alkylene group having 1 to 12 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, a hydrocarbon group having 3 to 12 carbon atoms including an alicyclic structure having 3 to 12 carbon atoms, and a hydrocarbon group having 6 to 12 carbon atoms including an aromatic ring having 6 to 12 carbon atoms], which is the modified group represented by the formula (II). The rubber composition according to claim 1 or 2 4. The rubber composition according to any one of claims 1 to 3, wherein the weight-average molecular weight of the modified liquid diene polymer (B) is 4,000 to 150,000.

5. The rubber composition according to any one of claims 1 to 4, wherein the modified liquid diene polymer (B) contains 20 to 100% by mass of structural units derived from butadiene based on the total amount of the modified liquid diene polymer.

6. The rubber composition according to claim 5, wherein the structural units derived from butadiene include 0 to 70 mol% of vinyl-grouped 1,2-bonding units relative to the total amount of 1,4-bonding units and vinyl-grouped 1,2-bonding units in the structural units derived from butadiene.

7. The rubber composition according to any one of claims 1 to 6, wherein the average number of modifying groups represented by formula (I) in the modified liquid diene polymer (B) is 1 to 30 per molecule of the modified liquid diene polymer.

8. The rubber composition according to any one of claims 1 to 7, wherein the solid rubber (A) is at least one selected from the group consisting of natural rubber, styrene-butadiene rubber, butadiene rubber, and isoprene rubber.

9. The rubber composition according to any one of claims 1 to 8, wherein the solid rubber (A) contains 0.1 to 70% by mass of structural units derived from styrene based on the total amount of the solid rubber (A).

10. The rubber composition according to any one of claims 1 to 9, wherein the solid rubber (A) is styrene-butadiene rubber having a weight-average molecular weight of 100,000 to 2,500,000.

11. The rubber composition according to any one of claims 1 to 10, wherein the filler (C) is carbon black and / or silica.

12. A tire rubber composition comprising a rubber composition according to any one of claims 1 to 11, and / or a crosslinked product of the rubber composition according to any one of claims 1 to 11.

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