Method for producing branched conjugated diene polymer, rubber composition, method for producing rubber composition, and method for producing tire

Abstract

To provide a method for producing a branched conjugated diene-based polymer excellent in low fuel consumption performance, abrasion resistance, wet-skid resistance, and fracture strength.SOLUTION: A method for producing a branched conjugated diene-based polymer includes: a polymerizing step of obtaining a conjugated diene-based polymer having an active end by polymerizing or copolymerizing a conjugated diene compound, or the conjugated diene compound and an aromatic vinyl compound with an alkali metal compound or an alkaline earth metal compound used as a polymerization initiator; and a branching step of introducing a branch structure by reacting a styrene derivative as a branching agent with the active end of the conjugated diene-based polymer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a branched conjugated diene-based polymer, a rubber composition, a method for producing a rubber composition, and a method for producing a tire. [Background technology]

[0002] From the viewpoint of environmental load, there has been an increasing demand for automobiles to have lower fuel consumption. In particular, there is a demand for improved fuel consumption in the materials used for the tread portion of automobile tires, which is in direct contact with the ground. In recent years, there has been a demand for the development of materials having low rolling resistance, i.e., low hysteresis loss. At the same time, there is a trend to reduce the weight of tires, which requires a reduction in the thickness of the tire tread, and at the same time, materials with high abrasion resistance are required for the tire tread. On the other hand, from the viewpoint of safety, materials used in the tire tread portion are required to have excellent wet skid resistance and sufficient fracture properties for practical use.

[0003] Materials that meet the various requirements as described above include rubber materials that contain a rubber-like polymer and a reinforcing filler such as carbon black or silica. The use of rubber materials containing silica can improve the balance between low hysteresis loss (an index of fuel economy) and wet skid resistance. Also, by introducing a functional group having affinity or reactivity with silica to the molecular end of a rubber-like polymer with high mobility, the dispersibility of silica in the rubber material can be improved, and further, the mobility of the molecular end of the rubber-like polymer can be reduced by bonding with silica particles, thereby reducing hysteresis loss. On the other hand, one method for improving the abrasion resistance is to increase the molecular weight of the rubber-like polymer, but increasing the molecular weight of the rubber-like polymer tends to deteriorate the processability when the rubber-like polymer is kneaded with a reinforcing filler. In view of these circumstances, attempts have been made to introduce a branched structure into rubber-like polymers in order to increase the molecular weight without impairing processability.

[0004] For example, a resin composition has been proposed in the past that contains silica and a modified conjugated diene polymer obtained by reacting an alkoxysilane containing an amino group with an active terminal of a conjugated diene polymer. In addition, modified conjugated diene polymers have been proposed that have a branched structure obtained by subjecting an active terminal of a polymer to a coupling reaction with a polyfunctional silane compound (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2007 / 114203 Brochure [Patent Document 2] International Publication No. 2016 / 133154 Brochure Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the method of introducing a branched structure into a conjugated diene polymer by coupling reaction of an active end of a polymer with a polyfunctional silane compound, the degree of branching of the modified conjugated diene polymer obtained by the method is largely dependent on the number of groups capable of reacting with the active end of the polymer possessed by the polyfunctional silane compound, and does not exceed the number of reactive groups. From the viewpoint of synthesis feasibility, there is a limit to the number of reactive groups that can be imparted to one polyfunctional silane, and therefore there is a problem in that the degree of branching of the modified conjugated diene polymer obtained is also limited.

[0007] Therefore, the present invention provides a method for producing a branched conjugated diene polymer that can produce a conjugated diene polymer with a higher degree of branching by introducing a branched structure into the conjugated diene polymer using only a modifier or a coupling agent, and that allows the lengths of the main chain and side chains to be adjusted, thereby providing a method for producing a branched conjugated diene polymer with a high degree of freedom in polymer design, thereby providing an object of the present invention to provide a method for producing a branched conjugated diene polymer that is excellent in fuel economy, abrasion resistance, wet skid resistance, and breaking strength. [Means for solving the problem]

[0008] Means for Solving the Problems of the Prior Art As a result of intensive research and investigation, the present inventors have found a method for producing a branched conjugated diene polymer, which can introduce a branch point into the main chain by reacting a conjugated diene polymer having an active terminal with a specific styrene derivative as a branching agent, and have completed the present invention. That is, the present invention is as follows.

[0009] [1] a polymerization step of polymerizing or copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene polymer having an active terminal; a branching step of reacting an active terminal of the conjugated diene polymer with a styrene derivative as a branching agent to introduce a branched structure; a reaction step of reacting a coupling agent or a polymerization terminator with the active terminal of the conjugated diene polymer obtained in the branching step, Furthermore, The coupling agent or the polymerization terminator has a nitrogen atom-containing group. A method for producing a branched conjugated diene polymer. [2] The method for producing a branched conjugated diene polymer according to [1] above, further comprising a step of adding a conjugated diene compound and / or an aromatic vinyl compound to the reaction system during and / or after the branching step. 〔3〕 The polymerization terminator is an alkoxy compound having a nitrogen atom-containing group. [1] or [2]A method for producing the branched conjugated diene polymer described in claim 1. 〔4〕 The styrene derivative is a compound represented by the following formula (1) and / or the following formula (2). 〔3〕 13. A method for producing the branched conjugated diene polymer according to claim 12.

[0010] [ka]

[0011] [ka]

[0012] In formulas (1) and (2), R 1 represents any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. X 1 , X 2 , X 3 is a single bond or an organic group containing any one selected from the group consisting of carbon, hydrogen, nitrogen, sulfur, and oxygen. Y 1 , Y 2 , Y 3 represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. They may be independent and the same or different.

[0013] 〔5〕 In the formula (1), R 1 is a hydrogen atom, and Y 1 is any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom; 〔4〕 A method for producing the branched conjugated diene polymer described in claim 1. 〔6〕 In the formula (2), X1 is a single bond, and Y 2 is any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom; 〔4〕 A method for producing the branched conjugated diene polymer described in claim 1. 〔7〕 In the formula (1), R 1 is a hydrogen atom, and Y 1 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom, 〔4〕 A method for producing the branched conjugated diene polymer described in claim 1. 〔8〕 In the formula (2), Y 2 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom, and Y 3 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom, 〔4〕 A method for producing the branched conjugated diene polymer described in claim 1. 〔9〕 In the formula (1), R 1 is a hydrogen atom, and Y 1 is an alkoxy group having 1 to 20 carbon atoms. 〔4〕 A method for producing the branched conjugated diene polymer described in claim 1. 〔10〕 In the formula (1), R 1 is a hydrogen atom, and X 1 is a single bond, and Y 1 is an alkoxy group having 1 to 20 carbon atoms. 〔4〕 A method for producing the branched conjugated diene polymer described in claim 1. 〔11〕 In the formula (2), X 2 is a single bond, and Y 2 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom, and X 3 is a single bond, and Y 3 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom, 〔4〕 A method for producing the branched conjugated diene polymer described in claim 1. 〔12〕 In the polymerization step, a nitrogen atom-containing vinyl compound is copolymerized, or The method further comprises a step of copolymerizing a conjugated diene compound and a nitrogen atom-containing vinyl compound, or a conjugated diene compound, a vinyl aromatic compound and a nitrogen atom-containing vinyl compound. The above [1] to 〔11〕 13. A method for producing the branched conjugated diene polymer according to claim 12. 〔13〕 The nitrogen atom-containing vinyl compound is a compound represented by the following formula (3) or (4): 〔12〕 A method for producing the branched conjugated diene polymer described in claim 1.

[0014] [ka]

[0015] In formula (3), R 7 ~R 9 each independently represents any one selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms; R 10 NR 13 It represents a divalent hydrocarbon group having 1 to 6 carbon atoms which may be interrupted by any one of O and S. R 11 ~R 13 each independently represents any one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, and a tri-substituted silyl group having an alkyl group having 1 to 30 carbon atoms and / or an aryl group having 6 to 30 carbon atoms on the silicon atom.

[0016] [ka]

[0017] In formula (4), R 7 ~R 9each independently represents any one selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms; R 10 NR 13 It represents a divalent hydrocarbon group having 1 to 6 carbon atoms which may be interrupted by any one of O and S. R 13 each independently represents any one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, and a tri-substituted silyl group having an alkyl group having 1 to 30 carbon atoms and / or an aryl group having 6 to 30 carbon atoms on the silicon atom. X is NR in the middle of the chain. 14 It is a divalent hydrocarbon group having 3 to 10 carbon atoms, which may be interrupted by any one of O and S, and represents a saturated ring-forming moiety in which all of the carbon-carbon bonds are single bonds, or an unsaturated ring-forming moiety in which at least some of the carbon-carbon bonds are double bonds. R 14 represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms.

[0018] 〔14〕 In the reaction step, reacting an active terminal of the conjugated diene polymer obtained in the branching step with a coupling agent represented by the following formula (S-2): [1] to

[13] 13. A method for producing the branched conjugated diene polymer according to claim 12.

[0019] [ka]

[0020] In formula (S-2), R 1 ~R 8 each independently represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, and may be the same or different. X 1 and X 4 is either (i) or (ii) below. (i)X1 and X 4 A portion of the group is selected from the group consisting of an alkoxyl group having 1 to 5 carbon atoms, a hydrocarbon group containing a 2-pyrrolidonyl group, and a group containing an epoxy group having 4 to 12 carbon atoms, and the remainder is a group derived from these groups or a single bond. (ii) X 1 and X 4 is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and X 1 and X 4 may be the same or different. X 2 is a group selected from the group consisting of an alkoxyl group having 1 to 5 carbon atoms, a hydrocarbon group containing a 2-pyrrolidonyl group, and a group containing an epoxy group having 4 to 12 carbon atoms, and the remainder is a group derived from these groups or a single bond. X 3 is a group containing 2 to 20 repeating alkylene glycol units. m is an integer from 3 to 200, n is an integer from 0 to 200, and k is an integer from 0 to 200.

[0021] 〔15〕 The above [1] to 〔14〕 obtaining a branched conjugated diene polymer by the production method according to any one of the above items; obtaining a rubber component containing 10% by mass or more of the branched conjugated diene polymer; A filler is added to 100 parts by mass of the rubber component. a step of obtaining a rubber composition by adding 5.0 parts by mass or more and 150 parts by mass or less of the carboxylic acid or carboxylic acid derivative to the rubber composition; The method for producing a rubber composition comprising the steps of: 〔16〕 The above 〔15〕 Obtaining a rubber composition by the method for producing a rubber composition according to the present invention; molding the rubber composition to obtain a tire; A tire manufacturing method comprising the steps of: Effect of the Invention

[0022] According to the present invention, by introducing a branch point into the main chain, a branched conjugated diene-based polymer having a higher degree of branching than when only a coupling agent is used can be produced, and a method for producing a branched conjugated diene-based polymer with a high degree of freedom in polymer design, which allows the lengths of the main chain and side chains to be adjusted, can be provided. As a result, a method for producing a branched conjugated diene-based polymer having excellent fuel economy, abrasion resistance, wet skid resistance, and breaking strength can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail. It should be noted that the following embodiment is merely an example for explaining the present invention, and the present invention is not limited to the following embodiment. The present invention can be practiced with appropriate modifications within the scope of the gist of the present invention.

[0024] [Method for producing branched conjugated diene polymer] The method for producing a branched conjugated diene polymer according to the present embodiment includes the steps of: a polymerization step of polymerizing or copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene polymer having an active terminal; a branching step of reacting an active terminal of the conjugated diene polymer with a styrene derivative as a branching agent to introduce a branched structure; has. The conjugated diene polymer constituting the branched conjugated diene polymer may be any of a homopolymer of a single conjugated diene compound, a polymer or copolymer of different types of conjugated diene compounds, and a copolymer of a conjugated diene compound and an aromatic vinyl compound. According to the method for producing a branched conjugated diene polymer of the present embodiment, by introducing a branch point into the main chain, it is possible to produce a conjugated diene polymer having a higher degree of branching than when a branched structure is introduced into a conjugated diene polymer using only a coupling agent, and it is also possible to adjust the lengths of the main chain and side chains.

[0025] (Polymerization process) In the polymerization step in the method for producing a branched conjugated diene polymer of the present embodiment, an alkali metal compound or an alkaline earth metal compound is used as a polymerization initiator to polymerize or copolymerize a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, to obtain a conjugated diene polymer having an active end. In the polymerization step, it is preferable to carry out polymerization by a propagation reaction through a living anionic polymerization reaction, whereby a conjugated diene polymer having an active terminal can be obtained.

[0026] <Polymerization initiator> As the polymerization initiator, an alkali metal compound or an alkaline earth metal compound is used. As the polymerization initiator, an organolithium compound is preferably used, and an organomonolithium compound is more preferably used. The organomonolithium compound is not limited to the following, but examples thereof include organomonolithium compounds of low molecular weight compounds and solubilized oligomeric organomonolithium compounds. In addition, the organomonolithium compound can be any of compounds having a carbon-lithium bond, a nitrogen-lithium bond, and a tin-lithium bond in terms of the bonding mode between the organic group and the lithium.

[0027] The amount of the polymerization initiator used is preferably determined depending on the targeted molecular weight of the conjugated diene polymer. The amount of a monomer such as a conjugated diene compound used relative to the amount of a polymerization initiator used relates to the degree of polymerization of a target conjugated diene polymer, i.e., tends to relate to the number average molecular weight and / or weight average molecular weight. Therefore, in order to increase the molecular weight of the conjugated diene polymer, the amount of the polymerization initiator should be adjusted to decrease, and in order to decrease the molecular weight, the amount of the polymerization initiator should be adjusted to increase.

[0028] From the viewpoint that the organomonolithium compound is used as one method for introducing nitrogen atoms into the conjugated diene polymer, it is preferably an alkyllithium compound having a substituted amino group or a dialkylaminolithium. In this case, a conjugated diene polymer having a nitrogen atom consisting of an amino group at the polymerization initiation terminal is obtained.

[0029] The substituted amino group is an amino group that does not have an active hydrogen or has a structure in which the active hydrogen is protected. Examples of alkyllithium compounds having an amino group that does not have an active hydrogen include, but are not limited to, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium. Examples of alkyllithium compounds having an amino group with an active hydrogen protected structure include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0030] Examples of dialkylaminolithium include, but are not limited to, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium-di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium morpholide, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.

[0031] These organomonolithium compounds having a substituted amino group can also be used as oligomeric organomonolithium compounds solubilized in normal hexane or cyclohexane by reacting them with a small amount of a polymerizable monomer, such as 1,3-butadiene, isoprene, or styrene.

[0032] The organomonolithium compound is preferably an alkyllithium compound from the viewpoints of industrial availability and ease of control of the polymerization reaction, in which case a conjugated diene-based polymer having an alkyl group at the polymerization initiation terminal can be obtained. Examples of the alkyl lithium compound include, but are not limited to, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, n-hexyl lithium, benzyl lithium, phenyl lithium, and stilbene lithium. As the alkyllithium compound, n-butyllithium and sec-butyllithium are preferred from the viewpoints of industrial availability and ease of control of the polymerization reaction.

[0033] These organomonolithium compounds may be used alone or in combination of two or more, and may also be used in combination with other organometallic compounds. Examples of the other organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds. Alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds, as well as alkaline earth metal alkoxides, sulfonates, carbonates, and amides. Organomagnesium compounds include, for example, dibutylmagnesium and ethylbutylmagnesium. Other examples of organometallic compounds include organoaluminum compounds.

[0034] In the polymerization step, the polymerization reaction mode is not limited to the following modes, but examples thereof include a batchwise mode (also called a "batch mode") and a continuous mode. In the continuous system, one or more connected reactors can be used. The continuous reactor is, for example, a tank type or a tube type equipped with an agitator. In the continuous system, preferably, the monomer, the inert solvent, and the polymerization initiator are continuously fed to the reactor, a polymer solution containing a polymer is obtained in the reactor, and the polymer solution is continuously discharged. The batch reactor may be, for example, a tank-type reactor equipped with a stirrer. In the batch reactor, preferably, a monomer, an inert solvent, and a polymerization initiator are fed, and if necessary, a monomer is added continuously or intermittently during polymerization to obtain a polymer solution in the reactor, and the polymer solution is discharged after the polymerization is completed. In the method for producing a branched conjugated diene polymer of this embodiment, in order to obtain a conjugated diene polymer having a high proportion of active ends in the polymerization step, a continuous system is preferred, which allows the polymer to be continuously discharged and subjected to the next reaction in a short time. In the continuous system, the number of reactors is not particularly limited, and one or two or more connected reactors can be used. The reactor is preferably one that can sufficiently contact the monomer and the polymerization initiator in a solution, and a tank type or a tube type with a stirrer is used. The number of reactors can be appropriately selected, but one is preferred from the viewpoint of space saving of the production equipment, and two or more are preferred from the viewpoint of improving productivity. When two or more reactors are used, it is more preferable to add the branching agent to the second or subsequent reactors.

[0035] The polymerization step for the conjugated diene polymer is preferably carried out in an inert solvent. Examples of the inert solvent include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific examples of the hydrocarbon solvent include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene, and hydrocarbons consisting of mixtures thereof. By treating the impurities, that is, allenes and acetylenes, with an organometallic compound before subjecting the polymer to the polymerization reaction, a conjugated diene-based polymer having a high concentration of active ends tends to be obtained, which is preferable since a modified conjugated diene-based polymer having a high modification rate tends to be obtained.

[0036] In the polymerization step, a polar compound (polar substance) may be added. This allows the aromatic vinyl compound to be randomly copolymerized with the conjugated diene compound. In addition, polar compounds tend to be usable as vinylating agents for controlling the microstructure of the conjugated diene portion. Furthermore, they tend to be effective in promoting the polymerization reaction.

[0037] Examples of polar compounds that can be used include, but are not limited to, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-oxolanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, and sodium amylate; and phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.

[0038] The amount of the polar compound used is not particularly limited and can be selected depending on the purpose, but is preferably 0.01 moles or more and 100 moles or less per mole of the polymerization initiator. Such polar compounds (vinylating agents) can be used in an appropriate amount according to the desired vinyl bond amount as regulators for the microstructure of the conjugated diene portion of the conjugated diene polymer. Many polar compounds simultaneously have an effective randomizing effect in the copolymerization of a conjugated diene compound and an aromatic vinyl compound, and tend to be usable as an adjuster for the distribution of the aromatic vinyl compound and as an adjuster for the amount of styrene blocks. As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, as described in JP-A-59-140211, a copolymerization reaction may be initiated with the total amount of styrene and a portion of 1,3-butadiene, and the remaining 1,3-butadiene may be intermittently added during the copolymerization reaction.

[0039] The polymerization temperature in the polymerization step is preferably a temperature at which living anionic polymerization proceeds, and from the viewpoint of productivity, is more preferably 0° C. or higher and 120° C. or lower. By setting the temperature within this range, it is possible to ensure a sufficient amount of the branching agent and coupling agent to react with the active terminals after the polymerization is completed.

[0040] <Conjugated diene compounds> The conjugated diene compound is not particularly limited, and may be any polymerizable monomer, and may include, but is not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, 1,3-hexadiene, etc. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of industrial availability. These may be used alone or in combination of two or more.

[0041] <Aromatic vinyl compounds> The aromatic vinyl compound may be any monomer that can be copolymerized with the conjugated diene compound, and is not particularly limited. Examples of the aromatic vinyl compound include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of industrial availability. These compounds may be used alone or in combination of two or more.

[0042] <Nitrogen atom-containing vinyl compounds> In the method for producing a branched conjugated diene polymer of the present embodiment, in the polymerization step described above, a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, and further a nitrogen atom-containing vinyl compound may be copolymerized. In the method for producing a branched conjugated diene polymer of the present embodiment, a step of copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, and further a nitrogen atom-containing vinyl compound may be carried out separately from the above-mentioned polymerization step and the branching step described later. This makes it possible to obtain a conjugated diene polymer having an active terminal and a portion derived from a nitrogen atom-containing vinyl compound. In the method for producing a branched conjugated diene polymer of the present embodiment, a branching step is carried out in which a styrene derivative as a branching agent described later is reacted with the active terminal of the conjugated diene polymer obtained in the polymerization step to introduce a branched structure. The polymer portion of the conjugated diene polymer obtained in the polymerization step other than the portion derived from the nitrogen atom-containing vinyl compound may be any one of a homopolymer of a single conjugated diene compound, a polymer or copolymer of different types of conjugated diene compounds, and a copolymer of a conjugated diene compound and an aromatic vinyl compound. According to the method for producing a branched conjugated diene-based polymer of the present embodiment, by introducing a branch point into the main chain, it is possible to produce a branched conjugated diene-based polymer having a higher degree of branching than when a branched structure is introduced into a conjugated diene-based polymer using only a coupling agent, and the lengths of the main chain and side chains can be easily adjusted. Furthermore, by copolymerizing a nitrogen atom-containing vinyl compound, a branched conjugated diene polymer containing a nitrogen atom in the polymer main chain and having an active terminal can be obtained. By using a nitrogen atom-containing vinyl compound in the polymerization step, a conjugated diene polymer containing a nitrogen atom in the main chain can be obtained. That is, a major feature is that the polymer is already in a modified state before carrying out the branching step described below or the reaction step with a coupling agent described below. In the method for producing a branched conjugated diene polymer of the present embodiment, the timing of introducing the nitrogen-atom-containing vinyl compound into the branched conjugated diene polymer may be before or after the formation of the branching points, i.e., before or after the branching step, or either one of them, and it is more preferable to introduce a large amount of the nitrogen-atom-containing vinyl compound after the formation of the branching points from the viewpoint of improving fuel economy performance. In order to preferentially introduce the nitrogen atom-containing vinyl compound after the formation of the branching points, i.e., after the branching step, it is preferable to add the nitrogen atom-containing vinyl compound simultaneously with the polymerization monomer and polymerize by suppressing the initial polymerization temperature to 60° C. or less, or to add the nitrogen atom-containing vinyl compound simultaneously with the branching agent. In the case of a continuous polymerization method, it is more preferable to add the nitrogen atom-containing vinyl compound together with the branching agent in the second or subsequent reactors.

[0043] The nitrogen-containing vinyl compound is not particularly limited as long as it is a monomer capable of anionically polymerizing with a nitrogen-containing vinyl compound. From the viewpoint of the reactivity between the target conjugated diene polymer and silica, however, the compounds represented by the following formulas (3) and (4) are preferred. The nitrogen atom-containing vinyl compounds may be used alone or in combination of two or more kinds.

[0044] [ka]

[0045] In formula (3), R 7 ~R 9 each independently represents any one selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms; R10 NR 13 It represents a divalent hydrocarbon group having 1 to 6 carbon atoms which may be interrupted by any one of O and S. R 11 ~R 13 each independently represents any one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, and a tri-substituted silyl group having an alkyl group having 1 to 30 carbon atoms and / or an aryl group having 6 to 30 carbon atoms on the silicon atom.

[0046] [ka]

[0047] In formula (4), R 7 ~R 10 is defined as in formula (3), and X is NR 14 It is a divalent hydrocarbon group having 3 to 10 carbon atoms, which may be interrupted by any one of O and S, and represents a saturated ring-forming moiety in which all of the carbon-carbon bonds are single bonds, or an unsaturated ring-forming moiety in which at least some of the carbon-carbon bonds are double bonds. R 14 represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms.

[0048] Examples of the compound represented by the formula (3) include, but are not limited to, N,N-dimethylvinylbenzylamine, N,N-diethylvinylbenzylamine, N,N-dipropylvinylbenzylamine, N,N-dibutylvinylbenzylamine, N,N-diphenylvinylbenzylamine, 2-dimethylaminoethylstyrene, 2-diethylaminoethylstyrene, 2-bis(trimethylsilyl)aminoethylstyrene, 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene, N,N-dimethyl-2-(4-vinylbenzyloxy)ethylamine, N 1 ,N 1 ,N 2 -Trimethyl-N 2-(4-vinylbenzyl)ethane-1,2-diamine, N,N-dimethyl-2-((4-vinylbenzyl)thio)ethylamine, and the like. Among these, 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene and N,N-dimethylvinylbenzylamine are preferred from the viewpoint of providing an excellent balance of low hysteresis loss, wet skid resistance, and dynamic modulus of elasticity when the resulting branched conjugated diene polymer is vulcanized with silica.

[0049] Examples of the compound represented by the formula (4) include, but are not limited to, 4-(2-pyrrolidinoethyl)styrene, 4-(2-piperidinoethyl)styrene, 4-(2-hexamethyleneiminoethyl)styrene, 4-(2-morpholinoethyl)styrene, 4-(2-thiazinoethyl)styrene, 4-(2-N-methylpiperazinoethyl)styrene, 1-((4-vinylphenoxy)methyl)pyrrolidine, 1-(4-vinylbenzyloxymethyl)pyrrolidine, 1-((4-vinylbenzyl)thiomethyl)pyrrolidine, and N-methyl-1-(pyrrolidin-1-yl)-N-(4-vinylbenzyl)methylamine. Among these, 4-(2-pyrrolidinoethyl)styrene is preferred from the viewpoint of providing an excellent balance of low hysteresis loss, wet skid resistance, and dynamic modulus of elasticity when the resulting branched conjugated diene polymer is vulcanized with silica.

[0050] In the above-mentioned polymerization step, when the nitrogen-containing vinyl compound is used, the amount of the nitrogen-containing vinyl compound added is not particularly limited and can be adjusted according to the purpose, etc. For example, although not limited to the following, it is preferably 0.5 to 100 mol, more preferably 1 to 20 mol, and further preferably 2 to 10 mol, per mol of the polymerization initiator. By adjusting the amount of the nitrogen-containing vinyl compound to be added in the polymerization step to 0.5 mol or more per mol of the polymerization initiator, a vulcanizate having excellent handling stability can be obtained. On the other hand, from the viewpoint of processability when the obtained branched conjugated diene polymer is made into a rubber composition containing silica, the amount of the branched conjugated diene polymer is preferably 100 mol or less per mol of the polymerization initiator. The timing of adding the nitrogen atom-containing vinyl compound in the polymerization step is not particularly limited. For example, the nitrogen atom-containing vinyl compound may be added simultaneously with the conjugated diene compound, or the conjugated diene compound and the vinyl aromatic compound, or may be added in portions during the (co)polymerization of the conjugated diene compound, or the conjugated diene compound and the vinyl aromatic compound.

[0051] (Branching process) In the method for producing a branched conjugated diene polymer of the present embodiment, a branching step is carried out in which a styrene derivative is reacted as a branching agent with the active terminal of the conjugated diene polymer obtained in the polymerization step. While the branching agent maintains its polymerization activity and polymerizes with the monomer, the functional group of the branching agent reacts with the active end of another polymer chain, forming a branched structure in the polymer. It is also possible to form a further branched structure by polymerizing and reacting the branched conjugated diene polymer into which the branched structure has been introduced with a monomer and a branching agent, or to react the branched conjugated diene polymer with a functional group to form a modified conjugated diene polymer, or to further extend the polymer chain by a coupling reaction. In this way, a branched conjugated diene polymer can be obtained by continuing the polymerization reaction as an aromatic vinyl compound and using a styrene derivative whose functional group reacts with the active end of the polymer as a branching agent.

[0052] <Branching agent> From the viewpoints of polymerization continuity and gelation prevention, the styrene derivative used as a branching agent in the branching step must have a main skeleton that leaves only one active end at the branch site after the branching reaction, and further, the styrene derivative portion formed after the branching reaction must have sufficient reactivity to react with other polymer active ends. That is, the styrene derivative is polymerized as styrene, and the styrene derivative is incorporated into the main chain while maintaining its polymerization activity, and another monomer is polymerized to the terminal that maintains its activity, so that the polymer chain extends further. In addition, the functional group of the styrene derivative that has been incorporated reacts with the active terminal of another polymer chain to form a bond, resulting in a branched structure. By repeating this reaction, the number of branches in the polymer chain increases, the polymer structure becomes more complex, and the molecular weight becomes larger. More specifically, the styrene derivative as the branching agent is preferably a compound having a vinyl group on the benzene ring and a functional group that quantitatively reacts with the polymer active end of living anionic polymerization. The functional group of the styrene derivative reacts one-to-one with the polymer active end, and the functional group is eliminated to form a single bond, while the vinyl group is polymerized with other monomers in the reactor, forming a branched structure in the polymer. The functional group other than the vinyl group of the styrene derivative is a group that is eliminated by nucleophilic substitution reaction with the polymer active end of living anionic polymerization, and examples of such functional groups include alkoxy groups, halogens, ester groups, formyl groups, ketone groups, amide groups, acid chloride groups, acid anhydride groups, and epoxy groups. By having the above-mentioned structure, the styrene derivative is incorporated into the main chain while maintaining its polymerization activity as styrene, and another monomer is polymerized to the terminal that maintains its activity, thereby further extending the polymer chain. In addition, the functional group of the incorporated styrene derivative reacts with the active terminal of another polymer chain to form a bond, resulting in a branched structure. By repeating this reaction, the number of branches in the polymer chain increases, the polymer structure becomes more complex, and the molecular weight becomes larger. From the viewpoint of the continuity of polymerization and the controllability of the polymer structure, it is also necessary that the functional group that is eliminated after the styrene derivative portion reacts with the active end of another polymer chain has little inhibitory effect on polymerization. Here, "little inhibitory effect on polymerization" means, for example, little side reaction of anionic polymerization, such as chain transfer reaction, deactivation during polymerization, and decrease in activity due to an increase in the degree of association of the polymer. The functional group of the styrene derivative as the branching agent must not excessively improve the polymerization activity, and must not deactivate the polymerization activity. When polymerizing a polymer by living anionic polymerization, it is important that the functional group does not have a hydrogen atom as a functional group that does not deactivate the active terminal, and is a hard base as defined based on Pearson's HASB rule, and more specifically, an alkoxy group or a halogen group can be mentioned. From these, the structure of the styrene derivative as the branching agent used in the production method of this embodiment can be selected from the viewpoints of reactivity with the active terminal and that the eliminated functional group does not inhibit polymerization. More specifically, it is preferable to use a branching agent represented by the following formula (1) having a styrene skeleton as the main skeleton, or a branching agent represented by the following formula (2) having a diphenylethylene skeleton as the main skeleton, from the viewpoints of suppressing chain transfer reactions, suppressing deactivation of active terminals, and preventing gelation.

[0053] [ka]

[0054] [ka]

[0055] In formulas (1) and (2), R 1 represents any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. X 1 , X 2 , X 3 is a single bond or an organic group containing any one selected from the group consisting of carbon, hydrogen, nitrogen, sulfur, and oxygen. Y 1 , Y 2 , Y 3 represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. They may be independent and the same or different.

[0056] The branching agent used in the branching step is a styrene derivative represented by the formula (1), R 1 is a hydrogen atom, and Y 1 is preferably any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom.

[0057] In the present embodiment, the branching agent used in the branching step is a styrene derivative represented by the formula (2), X 1 is a single bond, and Y 2 is preferably any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom.

[0058] In the present embodiment, the branching agent used in the branching step is a styrene derivative represented by the formula (1), R 1 is a hydrogen atom, and Y 1 is more preferably an alkoxy group having 1 to 20 carbon atoms or a halogen atom.

[0059] In the present embodiment, the branching agent used in the branching step is a styrene derivative represented by the formula (2), Y 2 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom, and Y 3 is more preferably an alkoxy group having 1 to 20 carbon atoms or a halogen atom.

[0060] In the present embodiment, the branching agent used in the branching step is a styrene derivative represented by the formula (1) R 1 is a hydrogen atom, and Y 1 is more preferably an alkoxy group having 1 to 20 carbon atoms.

[0061] In the present embodiment, the branching agent used in the branching step is a styrene derivative represented by the formula (1) R 1 is a hydrogen atom, and X 1 is a single bond, and Y 1 is even more preferably an alkoxy group having 1 to 20 carbon atoms.

[0062] In the present embodiment, the branching agent used in the branching step is a styrene derivative represented by the formula (2) X 2 is a single bond, and Y 2 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom, and X 3 is a single bond, and Y 3 is even more preferably an alkoxy group having 1 to 20 carbon atoms or a halogen atom.

[0063] Examples of the branching agent represented by the formula (1) include, but are not limited to, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tributoxy(3-vinylphenyl)silane, Examples of the silane include triisopropoxy(3-vinylphenyl)silane, trimethoxy(2-vinylphenyl)silane, triethoxy(2-vinylphenyl)silane, tripropoxy(2-vinylphenyl)silane, tributoxy(2-vinylphenyl)silane, triisopropoxy(2-vinylphenyl)silane, dimethoxymethyl(4-vinylphenyl)silane, diethoxymethyl(4-vinylphenyl)silane, dipropoxymethyl(4-vinylphenyl)silane, and dibutoxymethyl(4-vinylphenyl)silane.

[0064] Further examples thereof include diisopropoxymethyl(4-vinylphenyl)silane, dimethoxymethyl(3-vinylphenyl)silane, diethoxymethyl(3-vinylphenyl)silane, dipropoxymethyl(3-vinylphenyl)silane, dibutoxymethyl(3-vinylphenyl)silane, diisopropoxymethyl(3-vinylphenyl)silane, and dimethoxymethyl(2-vinylphenyl)silane.

[0065] Further examples thereof include diethoxymethyl(2-vinylphenyl)silane, dipropoxymethyl(2-vinylphenyl)silane, dibutoxymethyl(2-vinylphenyl)silane, diisopropoxymethyl(2-vinylphenyl)silane, dimethylmethoxy(4-vinylphenyl)silane, dimethylethoxy(4-vinylphenyl)silane, dimethylpropoxy(4-vinylphenyl)silane, dimethylbutoxy(4-vinylphenyl)silane, dimethylisopropoxy(4-vinylphenyl)silane, dimethylmethoxy(3-vinylphenyl)silane, dimethylethoxy(3-vinylphenyl)silane, dimethylpropoxy(3-vinylphenyl)silane, dimethylbutoxy(3-vinylphenyl)silane, and dimethylisopropoxy(3-vinylphenyl)silane.

[0066] Further examples thereof include dimethylmethoxy(2-vinylphenyl)silane, dimethylethoxy(2-vinylphenyl)silane, dimethylpropoxy(2-vinylphenyl)silane, dimethylbutoxy(2-vinylphenyl)silane, dimethylisopropoxy(2-vinylphenyl)silane, trimethoxy(4-isopropenylphenyl)silane, triethoxy(4-isopropenylphenyl)silane, and tripropoxy(4-isopropenylphenyl)silane.

[0067] Further examples thereof include tributoxy(4-isopropenylphenyl)silane, triisopropoxy(4-isopropenylphenyl)silane, trimethoxy(3-isopropenylphenyl)silane, triethoxy(3-isopropenylphenyl)silane, tripropoxy(3-isopropenylphenyl)silane, tributoxy(3-isopropenylphenyl)silane, triisopropoxy(3-isopropenylphenyl)silane, trimethoxy(2-isopropenylphenyl)silane, triethoxy(2-isopropenylphenyl)silane, tripropoxy(2-isopropenylphenyl)silane, tributoxy(2-isopropenylphenyl)silane, and triisopropoxy(2-isopropenylphenyl)silane.

[0068] In addition, dimethoxymethyl(4-isopropenylphenyl)silane, diethoxymethyl(4-isopropenylphenyl)silane, dipropoxymethyl(4-isopropenylphenyl)silane, dibutoxymethyl(4-isopropenylphenyl)silane, diisopropoxymethyl(4-isopropenylphenyl)silane, dimethoxymethyl(3-isopropenylphenyl)silane, diethoxymethyl(3-isopropenylphenyl)silane, dipropoxymethyl(3-isopropenylphenyl)silane nylphenyl)silane, dibutoxymethyl(3-isopropenylphenyl)silane, diisopropoxymethyl(3-isopropenylphenyl)silane, dimethoxymethyl(2-isopropenylphenyl)silane, diethoxymethyl(2-isopropenylphenyl)silane, dipropoxymethyl(2-isopropenylphenyl)silane, dibutoxymethyl(2-isopropenylphenyl)silane, and diisopropoxymethyl(2-isopropenylphenyl)silane.

[0069] Also, dimethylmethoxy(4-isopropenylphenyl)silane, dimethylethoxy(4-isopropenylphenyl)silane, dimethylpropoxy(4-isopropenylphenyl)silane, dimethylbutoxy(4-isopropenylphenyl)silane, dimethylisopropoxy(4-isopropenylphenyl)silane, dimethylmethoxy(3-isopropenylphenyl)silane, dimethylethoxy(3-isopropenylphenyl)silane, dimethylpropoxy(3-isopropenylphenyl)silane, dimethylbutoxy(3-isopropenylphenyl)silane, dimethylisopropoxy(3-isopropenylphenyl)silane, dimethylmethoxy(2-isopropenylphenyl)silane, dimethylethoxy(2-isopropenylphenyl)silane, dimethylpropoxy(2-isopropenylphenyl)silane, dimethylbutoxy(2-isopropenylphenyl)silane, dimethylisopropoxy( 2-isopropenylphenyl)silane, trichloro(4-vinylphenyl)silane, trichloro(3-vinylphenyl)silane, trichloro(2-vinylphenyl)silane, tribromo(4-vinylphenyl)silane, tribromo(3-vinylphenyl)silane, tribromo(2-vinylphenyl)silane, dichloromethyl(4-vinylphenyl)silane, dichloromethyl(3-vinylphenyl)silane, dichloromethyl(2-vinylphenyl)silane, dibromomethyl(4-vinylphenyl)silane, dibromomethyl(3-vinylphenyl)silane, dibromomethyl(2-vinylphenyl)silane, dimethylchloro(4-vinylphenyl)silane, dimethylchloro(3-vinylphenyl)silane, dimethylchloro(2-vinylphenyl)silane, dimethylbromo(4-vinylphenyl)silane, dimethylbromo(3-vinylphenyl)silane, dimethylbromo(2-vinylphenyl)silane, Examples of the silane include trimethoxy(4-vinylbenzyl)silane, triethoxy(4-vinylbenzyl)silane, and tripropoxy(4-vinylbenzyl)silane. Among these, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tributoxy(3-vinylphenyl)silane, triisopropoxy(3 ... tributoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tributoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tripeptoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripeptoxy(3-vinylphenyl)silane, tripeptoxy(3-vinylphenyl)sil Preferred is trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(4-vinylbenzyl)silane, and triethoxy(4-vinylbenzyl)silane, and further preferred are trimethoxy(4-vinylphenyl)silane and triethoxy(4-vinylphenyl)silane.

[0070] The branching agent represented by the formula (2) is not limited to the following, but may be, for example, 1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, 1,1-bis(4-triisopropoxysilylphenyl)ethylene, 1,1-bis(3-trimethoxysilylphenyl)ethylene, 1,1-bis(3-triethoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, 1,1-bis(3-triisopropoxysilylphenyl)ethylene, 1,1-bis(2-trimethoxysilylphenyl)ethylene, 1,1-bis(2-triethoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, Examples of the ethylene include 1,1-bis(2-tripentoxysilylphenyl)ethylene, 1,1-bis(2-triisopropoxysilylphenyl)ethylene, 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dipropylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dimethylethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dipropylethoxysilyl)phenyl)ethylene, 1,1-bis(4-trimethoxysilylbenzyl)ethylene, 1,1-bis(4-triethoxysilylbenzyl)ethylene, 1,1-bis(4-trippropoxysilylbenzyl)ethylene, and 1,1-bis(4-tripentoxysilylbenzyl)ethylene. Among these, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, and 1,1-bis(4-triisopropoxysilylphenyl)ethylene are preferred, with 1,1-bis(4-trimethoxysilylphenyl)ethylene being more preferred. By using the branching agents represented by the above formulas (1) and (2), the number of branches is increased, and the effects of improving the wear resistance and processability can be obtained.

[0071] The timing of adding the branching agent is not particularly limited and can be selected depending on the purpose, etc., but from the viewpoint of improving the absolute molecular weight of the branched conjugated diene-based polymer and improving the coupling rate, the timing is preferably when the raw material conversion rate after addition of the polymerization initiator is 20% or more, more preferably 40% or more, even more preferably 50% or more, even more preferably 65% ​​or more, and even more preferably 75% or more. During and / or after the branching step, a monomer as a desired raw material may be further added to the reaction system, and the polymerization step may be continued after the branching step, or the above-described contents may be repeated. Incidentally, "after the branching step" refers to after the branching agent is added. The monomer to be added is not particularly limited, but is preferably a conjugated diene compound and / or an aromatic vinyl compound. In particular, when a monomer is added during the branching step, from the viewpoint of improving the modification rate by alleviating steric hindrance at the branching point of the conjugated diene polymer, the monomer is preferably 5% or more of the total amount of conjugated diene monomers used in the polymerization step, for example, the total amount of butadiene, more preferably 10% or more, even more preferably 15% or more, even more preferably 20% or more, and even more preferably 25% or more. In this case, it is particularly preferable to add a monomer using a continuous polymerization process at the branching step, in an amount of 5% or more of the total amount of conjugated diene monomers used in the polymerization step, for example, the total amount of butadiene, from the viewpoint of improving the modification rate. The length of the main chain and side chains can be adjusted by changing the timing of adding the branching agent and the amount of monomer added, allowing for a high degree of freedom in polymer design.

[0072] The branched structure of the branched conjugated diene polymer obtained in the branching step in the method for producing a branched conjugated diene polymer of the present embodiment preferably has 3 or more and 24 or less branches, more preferably has 4 or more and 20 or less branches, and further preferably has 5 or more and 18 or less branches. By restricting the number of branches to 24 or less, it tends to be easier to react with a modifier having a functional group to form a modified conjugated diene polymer or to further extend the polymer chain by a coupling reaction, and by restricting the number of branches to 3 or more, the obtained branched conjugated diene polymer tends to have excellent processability and abrasion resistance.

[0073] The amount of the branching agent added is not particularly limited, and can be selected depending on the purpose, etc., but from the viewpoints of improving the terminal termination reaction rate of the conjugated diene polymer, improving the coupling rate, and continuity of polymerization after branching, the molar ratio of the branching agent to the amount of active polymerization initiator is preferably 1 / 2 or less and 1 / 100 or more, more preferably 1 / 3 or less and 1 / 50 or more, even more preferably 1 / 4 or less and 1 / 30 or more, even more preferably 1 / 6 or less and 1 / 25 or more, and even more preferably 1 / 8 or less and 1 / 12 or more.

[0074] As described above, further monomers may be added during and / or after the branching step, and the polymerization step may be continued after branching, or further branching agent may be added after the addition of monomers, and the addition of monomers may be repeated. By adding monomers, the steric hindrance around the branching points is alleviated, and the continuity of the polymerization is improved, and the coupling rate and modification rate are improved, so that the molecular weight of the polymer can be increased while a branched structure can be formed at a desired position. The monomer to be added may be an aromatic vinyl compound such as styrene, a conjugated diene compound such as butadiene, or a mixture thereof, and may be the same as or different from the type and ratio of the monomer to be polymerized initially, but from the viewpoint of continuity of polymerization, a conjugated diene compound is preferred. From the viewpoint of improving the heat resistance of the polymer, it is preferable to add an aromatic vinyl compound.

[0075] The branched conjugated diene polymer obtained in the branching step in the production method of the present embodiment has a Mooney viscosity measured at 110°C of preferably 10 or more and 150 or less, more preferably 15 or more and 140 or less, even more preferably 20 or more and 130 or less, and still more preferably 30 or more and 100 or less. When the Mooney viscosity is within the above range, the branched conjugated diene polymer obtained by the production method of the present embodiment tends to have excellent processability and abrasion resistance.

[0076] The weight average molecular weight of the branched conjugated diene polymer obtained in the branching step in the production method of this embodiment is preferably 10,000 or more and 1,500,000 or less, more preferably 100,000 or more and 1,000,000 or less, and even more preferably 200,000 or more and 900,000 or less. When the weight average molecular weight is within the above range, the branched conjugated diene polymer obtained by the production method of the present embodiment tends to be excellent in processability, abrasion resistance, and a balance of these properties. When producing an unmodified branched conjugated diene polymer, in order to reach a weight average molecular weight range of 100,000 to 1,000,000, it is necessary to control the amount of branching agent added to be within a range of 1 / 3 or less and 1 / 5 or more in molar ratio to the polymerization initiator, thereby preventing the polymerization initiator from being completely consumed before the coupling step while forming branches, and to make the number of functional groups of the coupling agent 2 or more. In order to reach a weight average molecular weight range of 200,000 to 900,000, it is necessary to control the amount of branching agent added to be within a range of 1 / 3 or less and 1 / 50 or more in molar ratio to the polymerization initiator, while making the number of functional groups of the coupling agent 3 or more. When producing a modified branched conjugated diene polymer, in order to reach a weight-average molecular weight in the range of 100,000 or more and 1,000,000 or less, it is necessary to control the amount of branching agent added to be in the range of 1 / 3 or less and 1 / 50 or more in molar ratio to the polymerization initiator, thereby preventing the polymerization initiator from being completely consumed before the coupling step while forming a branched structure, and to make the number of functional groups of the coupling agent two or more. In order to reach a weight-average molecular weight in the range of 200,000 or more and 900,000 or less, it is necessary to control the amount of branching agent added to be in the range of 1 / 3 or less and 1 / 50 or more in molar ratio to the polymerization initiator, and to make the number of functional groups of the coupling agent three or more.

[0077] The branched conjugated diene-based polymer obtained by the production method of the present embodiment may be a polymer of a conjugated diene monomer and a branching agent, or may be a copolymer of a conjugated diene monomer, a branching agent, and a monomer other than these. For example, when the conjugated diene monomer is butadiene or isoprene and is polymerized with a branching agent containing an aromatic vinyl moiety, the polymer chain is a so-called polybutadiene or polyisoprene, and the branched portion contains a structure derived from aromatic vinyl. By having such a structure, it is possible to improve the linearity of each polymer chain and improve the crosslinking density after vulcanization, and the abrasion resistance of the polymer is improved. Therefore, it is suitable for applications such as tires, resin modification, interior and exterior parts of automobiles, anti-vibration rubber, and footwear. When the conjugated diene polymer is used for tire tread applications, a copolymer of a conjugated diene monomer, an aromatic vinyl monomer, and a branching agent is suitable, and in the copolymer for this application, the bound conjugated diene content is preferably 40% by mass or more and 100% by mass or less, and more preferably 55% by mass or more and 80% by mass or less. Furthermore, the amount of bound aromatic vinyl in the branched conjugated diene polymer obtained by the production method of this embodiment is not particularly limited, but is preferably from 0% by mass to 60% by mass, and more preferably from 20% by mass to 45% by mass. When the bound conjugated diene amount and bound aromatic vinyl amount are within the above ranges, the balance between low hysteresis loss and wet skid resistance, abrasion resistance, and fracture properties tend to be excellent when made into a vulcanizate. The amount of bound aromatic vinyl can be measured by ultraviolet absorption of the phenyl group, and the amount of bound conjugated diene can also be calculated from the amount. Specifically, the amount can be measured according to the method described in the examples below.

[0078] In the branched conjugated diene polymer obtained by the production method of the present embodiment, the amount of vinyl bonds in the conjugated diene bond units is not particularly limited, but is preferably 10 mol % or more and 75 mol % or less, and more preferably 20 mol % or more and 65 mol % or less. When the vinyl bond amount is within the above range, the balance between low hysteresis loss and wet skid resistance, abrasion resistance, and breaking strength tend to be excellent when made into a vulcanizate. Here, when the branched conjugated diene polymer is a copolymer of butadiene and styrene, the vinyl bond amount (1,2-bond amount) in the butadiene bond unit can be determined by the Hampton method (RR Hampton, Analytical Chemistry, 21, 923 (1949)). Specifically, it can be measured by the method described in the examples below.

[0079] Regarding the microstructure of the branched conjugated diene polymer, when the bond amounts in the branched conjugated diene polymer obtained by the production method of the present embodiment are within the above-mentioned numerical ranges, and further, when the glass transition temperature of the branched conjugated diene polymer is within the range of -80°C or higher and -15°C or lower, a vulcanizate having an even better balance between low hysteresis loss and wet skid resistance tends to be obtained. The glass transition temperature is measured in accordance with ISO 22768:2006 by recording a DSC curve while increasing the temperature within a specified temperature range, and the peak top (inflection point) of the DSC differential curve is taken as the glass transition temperature.

[0080] When the branched conjugated diene polymer obtained by the production method of the present embodiment is a conjugated diene-aromatic vinyl copolymer, the branched conjugated diene polymer preferably has a small number of blocks in which 30 or more aromatic vinyl units are linked, or has no blocks. More specifically, when the branched conjugated diene polymer obtained by the production method of the present embodiment is a butadiene-styrene copolymer, the block in which 30 or more aromatic vinyl units are linked is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, based on the total amount of the branched conjugated diene polymer, in a known method in which the polymer is decomposed by the Kolthoff method (the method described in I.M.Kolthoff, et al., J.Polym.Sci.1,429(1946)) and the amount of polystyrene insoluble in methanol is analyzed.

[0081] When the branched conjugated diene polymer obtained by the production method of the present embodiment is a conjugated diene-aromatic vinyl copolymer, it is preferable that the proportion of aromatic vinyl units present alone is high from the viewpoint of improving fuel saving performance. Specifically, when the branched conjugated diene polymer obtained by the production method of the present embodiment is a butadiene-styrene copolymer, when the branched conjugated diene polymer is decomposed by an ozonolysis method known as the Tanaka et al. method (Polymer, 22, 1721 (1981)) and the styrene chain distribution is analyzed by GPC, it is preferable that the amount of isolated styrene is 40% by mass or more and the amount of chain styrene structures having 8 or more styrene chains is 5.0% by mass or less relative to the total bound styrene amount. In this case, the resulting vulcanized rubber tends to have excellent performance, particularly low hysteresis loss.

[0082] (Reaction process) In the method for producing a branched conjugated diene polymer of the present embodiment, it is preferable to carry out a step of performing a coupling reaction with a coupling agent, for example, a reactive compound having three or more functionalities, on the active terminal of the conjugated diene polymer obtained through the above-mentioned polymerization step and branching step, for example, a step of performing a coupling reaction with a coupling agent consisting of a silane sulfide compound described later, or a step of reacting an active terminal of the conjugated diene polymer with a polymerization terminator, for example, a reactive compound having two or less functionalities. Hereinafter, the step of reacting a coupling agent (coupling step) or the step of reacting to terminate polymerization (polymerization termination step) will be collectively referred to as a reaction step. In the reaction step, one of the active terminals of the conjugated diene polymer is reacted with a coupling agent or a polymerization terminator.

[0083] <Coupling process> In the method for producing a branched conjugated diene polymer of the present embodiment, it is preferable that the reaction step involves subjecting the conjugated diene polymer obtained through the above-mentioned polymerization step and branching step to a coupling reaction using a coupling agent. The coupling reaction can efficiently lengthen the molecular chain, and can also introduce branches into the polymer by using a coupling agent with three or more functionalities. Although the function of forming branches is common to the process using a branching agent, it is preferable to perform the coupling process in terms of forming branches while introducing desired elements such as nitrogen, sulfur, and silicon using a known coupling agent. In the coupling step, for example, a trifunctional or higher reactive compound, a coupling agent having a nitrogen atom-containing group, or a coupling agent consisting of a silane sulfide compound described below (hereinafter, these may be collectively referred to as "coupling agent") is preferably used for the active terminal of the conjugated diene polymer.

[0084] In the reaction step, for example, a branched conjugated diene polymer can be obtained by coupling reaction with a reactive compound having three or more functionalities, a coupling agent having a nitrogen atom-containing group, or a silane sulfide compound described below, which is a modifier containing silicon and sulfur atoms, at one active end of the conjugated diene polymer.

[0085] [Reactive compounds with three or more functional groups] In the method for producing a branched conjugated diene polymer of the present embodiment, the tri- or higher functional reactive compound used in the reaction step is preferably a tri- or higher functional reactive compound having a silicon atom.

[0086] Examples of the tri- or higher functional reactive compound having a silicon atom include, but are not limited to, halogenated silane compounds, epoxy silane compounds, vinylated silane compounds, alkoxy silane compounds, and the like.

[0087] Examples of halogenated silane compounds that are coupling agents include, but are not limited to, methyltrichlorosilane, tetrachlorosilane, tris(trimethylsiloxy)chlorosilane, tris(dimethylamino)chlorosilane, hexachlorodisilane, bis(trichlorosilyl)methane, 1,2-bis(trichlorosilyl)ethane, 1,2-bis(methyldichlorosilyl)ethane, 1,4-bis(trichlorosilyl)butane, and 1,4-bis(methyldichlorosilyl)butane.

[0088] Examples of the epoxidized silane compound that is a coupling agent include, but are not limited to, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and epoxy-modified silicone.

[0089] Examples of the alkoxysilane compound that is a coupling agent include, but are not limited to, tetramethoxysilane, tetraethoxysilane, triphenoxymethylsilane, 1,2-bis(triethoxysilyl)ethane, and methoxy-substituted polyorganosiloxane.

[0090] [Coupling agents having nitrogen atom-containing groups] Examples of coupling agents having a nitrogen atom-containing group include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds having a nitrogen atom-containing group, vinyl compounds having a nitrogen atom-containing group, epoxy compounds having a nitrogen atom-containing group, alkoxysilane compounds having a nitrogen atom-containing group, and protected amine compounds having a nitrogen atom-containing group and capable of forming a primary or secondary amine.

[0091] In the coupling agent having a nitrogen atom-containing group, the nitrogen atom-containing group can preferably include a functional group derived from an amine compound that does not have active hydrogen, and the amine compound can include, for example, a tertiary amine compound, and a protected amine compound in which the above-mentioned active hydrogen is replaced with a protective group.Other compounds that can form a nitrogen atom-containing group can include an imine compound represented by the general formula -N=C, and an alkoxysilane compound that is bonded to the above-mentioned nitrogen atom-containing group.

[0092] Examples of isocyanate compounds that are coupling agents having a nitrogen atom-containing group include, but are not limited to, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, and 1,3,5-benzene triisocyanate.

[0093] Examples of isocyanuric acid derivatives that are coupling agents having a nitrogen atom-containing group include, but are not limited to, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 1,3,5-tris(3-triethoxysilylpropyl)isocyanurate, 1,3,5-tri(oxiran-2-yl)-1,3,5-triazinane-2,4,6-trione, 1,3,5-tris(isocyanatomethyl)-1,3,5-triazinane-2,4,6-trione, and 1,3,5-trivinyl-1,3,5-triazinane-2,4,6-trione.

[0094] Examples of carbonyl compounds that are coupling agents having a nitrogen atom-containing group include, but are not limited to, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-(2-methoxyethyl)-2-imidazolidinone, N-methyl-2-pyrrolidone, N-methyl-2-piperidone, N-methyl-2-quinolone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, and the like. Examples of such amines include methyl-2-pyridyl ketone, methyl-4-pyridyl ketone, propyl-2-pyridyl ketone, di-4-pyridyl ketone, 2-benzoylpyridine, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, N,N-diethylmethylcarbamate, N,N-diethylacetamide, N,N-dimethyl-N',N'-dimethylaminoacetamide, N,N-dimethylpicolinic acid amide, and N,N-dimethylisonicotinic acid amide.

[0095] Examples of vinyl compounds that are coupling agents having a nitrogen atom-containing group include, but are not limited to, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylmaleimide, N-methylphthalimide, N,N-bistrimethylsilylacrylamide, morpholinoacrylamide, 3-(2-dimethylaminoethyl)styrene, (dimethylamino)dimethyl-4-vinylphenylsilane, 4,4'-vinylidenebis(N,N-dimethylaniline), 4,4'-vinylidenebis(N,N-diethylaniline), 1,1-bis(4-morpholinophenyl)ethylene, and 1-phenyl-1-(4-N,N-dimethylaminophenyl)ethylene.

[0096] The epoxy compound, which is a coupling agent having a nitrogen atom-containing group, includes, but is not limited to, for example, an epoxy group-containing hydrocarbon compound bonded to an amino group, and further includes an epoxy group-containing hydrocarbon compound bonded to an ether group. Such an epoxy compound includes, but is not limited to, for example, an epoxy compound represented by the general formula (i):

[0097] [ka]

[0098] In the formula (i), R is a divalent or higher organic group having at least one polar group selected from the group consisting of a divalent or higher hydrocarbon group, or an oxygen-containing polar group such as an ether, epoxy, or ketone, a sulfur-containing polar group such as a thioether or thioketone, and a nitrogen-containing polar group such as a tertiary amino group or an imino group.

[0099] The divalent or higher hydrocarbon group is a saturated or unsaturated, linear, branched or cyclic hydrocarbon group, and includes an alkylene group, an alkenylene group, a phenylene group, etc. A hydrocarbon group having 1 to 20 carbon atoms is preferable. Examples thereof include methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-, m-, p-phenylene, m-, p-xylene, and bis(phenylene)-methane.

[0100] In the formula (i), R 1 , R 4 is a hydrocarbon group having 1 to 10 carbon atoms, R 1 , R 4 may be the same or different from each other. In the formula (i), R 2 , R 5 is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R 2 , R 5 may be the same or different from each other. In the formula (i), R 3 is a hydrocarbon group having 1 to 10 carbon atoms, or a structure represented by the following formula (ii): R 1 , R 2 , R 3 may be bonded to each other to form a cyclic structure. Also, R 3 When R is a hydrocarbon group, R may be bonded to R to form a cyclic structure. 3 The N bonded to R may be directly bonded to the N bonded to R. In the above formula (i), n is an integer of 1 or more, and m is 0 or an integer of 1 or more.

[0101] [ka]

[0102] In the formula (ii), R 1 , R 2 is R in the formula (i). 1 , R 2is defined similarly to R 1 , R 2 may be the same or different from each other.

[0103] The epoxy compound, which is a coupling agent having a nitrogen atom-containing group, is preferably one having an epoxy group-containing hydrocarbon group, more preferably one having a glycidyl group-containing hydrocarbon group.

[0104] The epoxy group-containing hydrocarbon group bonded to the amino group or ether group is not particularly limited, but examples thereof include a glycidylamino group, a diglycidylamino group, and a glycidoxy group. More preferred molecular structures are epoxy group-containing compounds each having a glycidylamino group or a diglycidylamino group, and a glycidoxy group, and examples thereof include compounds represented by the following general formula (iii).

[0105] [ka]

[0106] In the formula (iii), R is defined as R in the formula (i), 6 is a hydrocarbon group having 1 to 10 carbon atoms or a structure represented by the following formula (iv): R 6 When R is a hydrocarbon group, R may be bonded to R to form a cyclic structure. In this case, R 6 The N bonded to R may be directly bonded to the N bonded to R. In formula (iii), n is an integer of 1 or more, and m is 0 or an integer of 1 or more.

[0107] [ka]

[0108] As the epoxy compound which is a coupling agent having a nitrogen atom-containing group, a compound having one or more diglycidylamino groups and one or more glycidoxy groups in the molecule is particularly preferred.

[0109] The epoxy compound used as the coupling agent having a nitrogen atom-containing group is not limited to the following, but examples thereof include N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidoxy-cyclohexane, 4-(4-glycidoxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidoxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4-glycidoxybenzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazinyl)-glycidoxybenzene, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl -m-xylylenediamine, 4,4-methylene-bis(N,N-diglycidylaniline), 1,4-bis(N,N-diglycidylamino)cyclohexane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, 4,4'-bis(diglycidylamino)benzophenone, 4-(4-glycidylpiperazinyl)-(N,N-diglycidyl)aniline, 2-[2-(N,N-diglycidylamino)ethyl]-1-glycidylpyrrolidine, N,N-diglycidylaniline, 4,4'-diglycidyl-dibenzylmethylamine, N,N-diglycidylaniline, N,N-diglycidylorthotoluidine, and N,N-diglycidylaminomethylcyclohexane are examples thereof. Among these, particularly preferred ones include N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0110] Examples of alkoxysilane compounds that are coupling agents having a nitrogen atom-containing group include, but are not limited to, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperazino)propyltriethoxysilane, 1-[3-(triethoxysilyl)-propyl]-3-methylhexahydropyrimidine, and 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane.

[0111] Further examples thereof include 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 3-dimethylamino-2-(dimethylaminomethyl)propyltrimethoxysilane, bis(3-dimethoxymethylsilylpropyl)-N-methylamine, bis(3-trimethoxysilylpropyl)-N-methylamine, and bis(3-triethoxysilylpropyl)methylamine.

[0112] Also, tris(trimethoxysilyl)amine, tris(3-trimethoxysilylpropyl)amine, N,N,N',N'-tetra(3-trimethoxysilylpropyl)ethylenediamine, 3-isocyanatopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclopentane, Examples of the hexane include hexane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2,2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctane, and 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxa-2-silacyclooctane.

[0113] Examples of protected amine compounds that are coupling agents having a nitrogen atom-containing group and can form primary or secondary amines include compounds having an unsaturated bond and a protected amine in the molecule, but are not limited to the following: 4,4'-vinylidenebis[N,N-bis(trimethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(triethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(trimethylsilyl)aniline], 4, Examples thereof include 4'-vinylidenebis[N-methyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(t-butyldimethylsilyl)aniline], 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N-methyl-N-(trimethylsilyl)aminophenyl]ethylene, and 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N,N-dimethylaminophenyl]ethylene.

[0114]

[0043] Examples of coupling agents having a nitrogen atom-containing group, which are protected amine compounds capable of forming a primary or secondary amine and have an alkoxysilane and a protected amine in the molecule, include, but are not limited to, N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, and N,N-bis(trimethylsilyl)aminoethylmethyldiethoxysilane.

[0115] Further examples include N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, and 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane.

[0116] Further examples thereof include 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, and 2,2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane.

[0117] In addition, 2,2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-ethylidene-3-(triethoxysilyl)-1-propanamine, N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine, N-(4-N,N-dimethylamine) Nobenzylidene)-3-(triethoxysilyl)-1-propanamine, etc., such as N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, 3-(benzylideneamino)propyltrimethoxysilane, 3-(benzylideneamino)propyltrimethoxysilane, 3-(benzylideneamino)propyltriethoxysilane, 3-(benzylideneamino)propyltripropylsilane, etc.

[0118] Particularly preferred alkoxysilane compounds that are coupling agents having a nitrogen atom-containing group include, but are not limited to, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-tripropoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl- [1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, and tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane.

[0119] In addition, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, pentakis(3-trimethoxysilylpropyl)-diethylenetriamine, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane )propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]silane.

[0120] Also, 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane, 1-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexane, 1-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexane, 3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexane Examples of such phosphate esters include hexyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]ether, (3-trimethoxysilylpropyl)phosphate, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]phosphate, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)phosphate, and tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]phosphate.

[0121] The coupling agent used in the reaction step is preferably a silane sulfide compound represented by the following formula (5).

[0122] [ka]

[0123] In formula (5), Si represents a silicon atom, O represents an oxygen atom, and S represents a sulfur atom, and x is an integer of 1 to 3, y is an integer of 0 or 1 to 2, and x+y is 3. R 1 , R 2 , R 4 may be the same or different and represent an alkyl group having 1 to 16 carbon atoms; R 3 represents an aryl group having 6 to 16 carbon atoms, an alkylene group having 1 to 16 carbon atoms, or an alkyl chain having 1 to 16 carbon atoms.

[0124] The coupling agent represented by (5) above is not limited to the following, but examples thereof include S-trimethylsilylmercaptopropyltrimethoxysilane, S-trimethylsilylmercaptopropyltriethoxysilane, S-trimethylsilylmercaptopropyltripropoxysilane, S-trimethylsilylmercaptopropyltributoxysilane, S-trimethylsilylmercaptoethyltrimethoxysilane, S-trimethylsilylmercaptoethyltriethoxysilane, S-trimethylsilylmercaptoethyltripropoxysilane, S-trimethylsilylmercaptoethyltributoxysilane, S-trimethylsilylmercaptomethyltrimethoxysilane, and S-trimethylsilylmercaptomethyltriethoxysilane. Examples of the silane include S-trimethylsilylmercaptomethyltripropoxysilane, S-trimethylsilylmercaptomethyltributoxysilane, S-trimethylsilylmercapto-2,2-dimethylpropyltrimethoxysilane, S-trimethylsilylmercapto-2,2-dimethylpropyltriethoxysilane, S-trimethylsilylmercapto-2,2-dimethylpropyltripropoxysilane, S-trimethylsilylmercapto-2,2-dimethylpropyltributoxysilane, S-trimethylsilylmercapto-2-methylpropyltrimethoxysilane, S-trimethylsilylmercapto-2-methylpropyltriethoxysilane, and S-trimethylsilylmercapto-2-methylpropyltripropoxysilane.

[0125] Also, S-trimethylsilylmercapto-2-methylpropyltributoxysilane, S-trimethylsilylmercaptopropylmethyldimethoxysilane, S-trimethylsilylmercaptopropylmethyldiethoxysilane, S-trimethylsilylmercaptopropylmethyldipropoxysilane, S-trimethylsilylmercaptopropylmethyldibutoxysilane, S-trimethylsilylmercaptoethylmethyldimethoxysilane, S-trimethylsilylmercaptoethylmethyldiethoxysilane, S-trimethylsilylmercaptoethylmethyldipropoxysilane, S-trimethylsilylmercaptoethylmethyldibutoxysilane, S-trimethylsilylmercaptomethylmethyldimethoxysilane, Examples of suitable mercaptomethyl methyl diethoxysilane include S-trimethylsilyl mercaptomethyl methyl dipropoxysilane, S-trimethylsilyl mercaptomethyl methyl dibutoxysilane, S-trimethylsilyl mercapto-2,2-dimethylpropyl methyl dimethoxysilane, S-trimethylsilyl mercapto-2,2-dimethylpropyl methyl diethoxysilane, S-trimethylsilyl mercapto-2,2-dimethylpropyl methyl dipropoxysilane, S-trimethylsilyl mercapto-2,2-dimethylpropyl methyl dibutoxysilane, S-trimethylsilyl mercapto-2-methylpropyl methyl dimethoxysilane, and S-trimethylsilyl mercapto-2-methylpropyl methyl diethoxysilane.

[0126] Also, S-trimethylsilylmercapto-2-methylpropylmethyldipropoxysilane, S-trimethylsilylmercapto-2-methylpropylmethyldibutoxysilane, S-trimethylsilylmercaptopropyldimethylmethoxysilane, S-trimethylsilylmercaptopropyldimethylethoxysilane, S-trimethylsilylmercaptopropyldimethylpropoxysilane, S-trimethylsilylmercaptopropyldimethylbutoxysilane, S-trimethylsilylmercaptoethyldimethylmethoxysilane, S-trimethylsilylmercaptoethyldimethylethoxysilane, S-trimethylsilylmercaptoethyldimethylpropoxysilane, S-trimethylsilylmercaptoethyldimethylbutoxysilane, S-trimethylsilylmercaptomethyldi Examples of the silane include methyl methoxy silane, S-trimethylsilyl mercapto methyl dimethyl ethoxy silane, S-trimethylsilyl mercapto methyl dimethyl propoxy silane, S-trimethylsilyl mercapto methyl dimethyl butoxy silane, S-trimethylsilyl mercapto-2,2-dimethyl propyl dimethyl methoxy silane, S-trimethylsilyl mercapto-2,2-dimethyl propyl dimethyl ethoxy silane, S-trimethylsilyl mercapto-2,2-dimethyl propyl dimethyl propoxy silane, S-trimethylsilyl mercapto-2,2-dimethyl propyl dimethyl butoxy silane, S-trimethylsilyl mercapto-2-methyl propyl dimethyl methoxy silane, and S-trimethylsilyl mercapto-2-methyl propyl dimethyl ethoxy silane.

[0127] Also, S-trimethylsilylmercapto-2-methylpropyldimethylpropoxysilane, S-trimethylsilylmercapto-2-methylpropyldimethylbutoxysilane, S-triethylsilylmercaptopropyltrimethoxysilane, S-triethylsilylmercaptopropyltriethoxysilane, S-triethylsilylmercaptopropyltripropoxysilane, S-triethylsilylmercaptopropyltributoxysilane, S-triethylsilylmercaptoethyltrimethoxysilane, S-triethylsilylmercaptoethyltriethoxysilane, S-triethylsilylmercaptoethyltripropoxysilane, S-triethylsilylmercaptoethyltributoxysilane, S-triethylsilylmercaptomethyltrimethoxysilane, S-triethyl Examples of the silylmercaptomethyltriethoxysilane include S-triethylsilylmercaptomethyltripropoxysilane, S-triethylsilylmercaptomethyltributoxysilane, S-triethylsilylmercapto-2,2-dimethylpropyltrimethoxysilane, S-triethylsilylmercapto-2,2-dimethylpropyltriethoxysilane, S-triethylsilylmercapto-2,2-dimethylpropyltripropoxysilane, S-triethylsilylmercapto-2,2-dimethylpropyltributoxysilane, S-triethylsilylmercapto-2-methylpropyltrimethoxysilane, S-triethylsilylmercapto-2-methylpropyltriethoxysilane, and S-triethylsilylmercapto-2-methylpropyltripropoxysilane.

[0128] Also, S-triethylsilylmercapto-2-methylpropyltributoxysilane, S-triethylsilylmercaptopropylmethyldimethoxysilane, S-triethylsilylmercaptopropylmethyldiethoxysilane, S-triethylsilylmercaptopropylmethyldipropoxysilane, S-triethylsilylmercaptopropylmethyldibutoxysilane, S-triethylsilylmercaptoethylmethyldimethoxysilane, S-triethylsilylmercaptoethylmethyldiethoxysilane, S-triethylsilylmercaptoethylmethyldipropoxysilane, S-triethylsilylmercaptoethylmethyldibutoxysilane, S-triethylsilylmercaptomethylmethyldimethoxysilane, Examples of suitable mercaptosilanes include S-triethylsilylmercaptomethylmethyldiethoxysilane, S-triethylsilylmercaptomethylmethyldipropoxysilane, S-triethylsilylmercaptomethylmethyldibutoxysilane, S-triethylsilylmercapto-2,2-dimethylpropylmethyldimethoxysilane, S-triethylsilylmercapto-2,2-dimethylpropylmethyldiethoxysilane, S-triethylsilylmercapto-2,2-dimethylpropylmethyldipropoxysilane, S-triethylsilylmercapto-2,2-dimethylpropylmethyldibutoxysilane, S-triethylsilylmercapto-2-methylpropylmethyldimethoxysilane, and S-triethylsilylmercapto-2-methylpropylmethyldiethoxysilane.

[0129] Also, S-triethylsilylmercapto 2-methylpropyl methyldipropoxysilane, S-triethylsilylmercapto 2-methylpropyl methyldibutoxysilane, S-triethylsilylmercaptopropyl dimethylmethoxysilane, S-triethylsilylmercaptopropyl dimethylethoxysilane, S-triethylsilylmercaptopropyl dimethylpropoxysilane, S-triethylsilylmercaptopropyl dimethylbutoxysilane, S-triethylsilylmercaptoethyl dimethylmethoxysilane, S-triethylsilylmercaptoethyl dimethylethoxysilane, S-triethylsilylmercaptoethyl dimethylpropoxysilane, S-triethylsilylmercaptoethyl dimethylbutoxysilane, S-triethylsilylmercaptomethyldimethylmethoxysilane, S-triethylsilylmercaptomethyldimethylethoxysilane, S-triethylsilylmercaptomethyldimethylpropoxysilane, S-triethylsilylmercaptomethyldimethylbutoxysilane, S S-triethylsilylmercapto-2,2-dimethylpropyldimethylmethoxysilane, S-triethylsilylmercapto-2,2-dimethylpropyldimethylethoxysilane, S-triethylsilylmercapto-2,2-dimethylpropyldimethylpropoxysilane, S-triethylsilylmercapto-2,2-dimethylpropyldimethylbutoxysilane, S-dimethyltertbutylsilylmercaptopropyltrimethoxysilane, S-dimethyltertbutylsilylmercaptopropyltriethoxysilane, S-dimethyltertbutylsilylmercaptopropyltripropoxysilane, S-dimethyltertbutylsilylmercaptopropyltributoxysilane, S-dimethyltertbutylsilylmercaptoethyltrimethoxysilane, S-dimethyltertbutylsilylmercaptoethyltriethoxysilane, S-dimethyltertbutylsilylmercaptoethyltripropoxysilane, and S-dimethyltertbutylsilylmercaptoethyltributoxysilane.

[0130] Also, S-dimethyl tertbutylsilyl mercaptomethyl trimethoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl triethoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl tripropoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl tributoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl trimethoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl triethoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl tripropoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl tributoxysilane, S-dimethyl tertbutylsilyl mercapto-2-methylpropyl trimethoxysilane, S-dimethyl tertbutylsilyl Examples of such silane include S-dimethyl tertbutylsilyl mercapto-2-methylpropyl triethoxysilane, S-dimethyl tertbutylsilyl mercapto-2-methylpropyl tripropoxysilane, S-dimethyl tertbutylsilyl mercapto-2-methylpropyl tributoxysilane, S-dimethyl tertbutylsilyl mercaptopropyl methyl dimethoxysilane, S-dimethyl tertbutylsilyl mercaptopropyl methyl diethoxysilane, S-dimethyl tertbutylsilyl mercaptopropyl methyl dipropoxysilane, S-dimethyl tertbutylsilyl mercaptopropyl methyl dibutoxysilane, S-dimethyl tertbutylsilyl mercaptoethyl methyl dimethoxysilane, S-dimethyl tertbutylsilyl mercaptoethyl methyl diethoxysilane, and S-dimethyl tertbutylsilyl mercaptoethyl methyl dipropoxysilane.

[0131] Also, S-dimethyl tertbutylsilyl mercaptoethyl methyl dibutoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl methyl dimethoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl methyl diethoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl methyl dipropoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl methyl dibutoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl methyl dimethoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl methyl diethoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl methyl dipropoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyl methyl dibutoxysilane, S-dimethyl tertbutylsilyl Examples of such silylmercapto include S-dimethyl tertbutylsilylmercapto-2-methylpropyl methyldimethoxysilane, S-dimethyl tertbutylsilylmercapto-2-methylpropyl methyldiethoxysilane, S-dimethyl tertbutylsilylmercapto-2-methylpropyl methyldipropoxysilane, S-dimethyl tertbutylsilylmercapto-2-methylpropyl methyldibutoxysilane, S-dimethyl tertbutylsilylmercaptopropyl dimethylmethoxysilane, S-dimethyl tertbutylsilylmercaptopropyl dimethylethoxysilane, S-dimethyl tertbutylsilylmercaptopropyl dimethylpropoxysilane, S-dimethyl tertbutylsilylmercaptopropyl dimethylbutoxysilane, S-dimethyl tertbutylsilylmercaptoethyl dimethylmethoxysilane, and S-dimethyl tertbutylsilylmercaptoethyl dimethylethoxysilane.

[0132] Also, S-dimethyl tertbutylsilyl mercaptoethyl dimethylpropoxysilane, S-dimethyl tertbutylsilyl mercaptoethyl dimethylbutoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl dimethylmethoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl dimethylethoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl dimethylpropoxysilane, S-dimethyl tertbutylsilyl mercaptomethyl dimethylbutoxysilane, S-dimethyl tertbutylsilyl mercapto-2,2-dimethylpropyldimethylmethoxysilane, S-dimethyl tertbutylsilyl mercapto-2, Examples of the silane include 2-dimethylpropyldimethylethoxysilane, S-dimethyltertbutylsilylmercapto-2,2-dimethylpropyldimethylpropoxysilane, S-dimethyltertbutylsilylmercapto-2,2-dimethylpropyldimethylbutoxysilane, S-dimethyltertbutylsilylmercapto-2-methylpropyldimethylmethoxysilane, S-dimethyltertbutylsilylmercapto-2-methylpropyldimethylethoxysilane, S-dimethyltertbutylsilylmercapto-2-methylpropyldimethylpropoxysilane, and S-dimethyltertbutylsilylmercapto-2-methylpropyldimethylbutoxysilane.

[0133] In the method for producing a branched conjugated diene-based polymer of the present embodiment, in the reaction step, It is preferable to react a coupling agent represented by the following formula (S-2) with the active terminal of the conjugated diene polymer obtained in the branching step.

[0134] [ka]

[0135] In formula (S-2), R 1 ~R 8 each independently represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, and may be the same or different. X1 and X 4 is either (i) or (ii) below. (i): Multiple Xs 1 and X 4 A part of these is a group selected from the group consisting of an alkoxyl group having 1 to 5 carbon atoms, a hydrocarbon group containing a 2-pyrrolidonyl group, and a group containing an epoxy group having 4 to 12 carbon atoms, and the remainder is a group derived from these groups or a single bond. (ii):X 1 and X 4 is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and X 1 and X 4 may be the same or different. X 2 is a group selected from the group consisting of an alkoxyl group having 1 to 5 carbon atoms, a hydrocarbon group containing a 2-pyrrolidonyl group, and a group containing an epoxy group having 4 to 12 carbon atoms, and the remainder is a group derived from these groups or a single bond. X 3 is a group containing 2 to 20 repeating alkylene glycol units. m is an integer from 3 to 200, n is an integer from 0 to 200, and k is an integer from 0 to 200. From the viewpoint of ease of synthesis of the coupling agent and ease of use in coupling reactions, m is preferably an integer of 60-100, n is preferably an integer of 0-40, and k is preferably an integer of 100-150.

[0136] The coupling agent represented by the formula (S-2) is preferably a compound represented by the following formula (Z-1). By using the coupling agent represented by the formula (S-2), the degree of branching is further increased, and the effect of improving processability is obtained.

[0137] [ka]

[0138] <Branched conjugated diene polymer obtained through polymerization process, branching process, and reaction process> In the method for producing a branched conjugated diene polymer of the present embodiment, the branched conjugated diene polymer obtained through the above-mentioned reaction step, particularly the step of reacting a coupling agent, preferably contains a structure derived from a compound having a nitrogen atom-containing group represented by the following general formula (i) or any of the general formulas (A) to (C).

[0139] [ka]

[0140] In the formula (i), R is a divalent or higher organic group having at least one polar group selected from a divalent or higher hydrocarbon group, or a polar group having oxygen such as ether, epoxy, or ketone, a polar group having sulfur such as thioether or thioketone, or a polar group having nitrogen such as a tertiary amino group or imino group.

[0141] The divalent or higher hydrocarbon group is a saturated or unsaturated, linear, branched or cyclic hydrocarbon group, and includes an alkylene group, an alkenylene group, a phenylene group, etc. A hydrocarbon group having 1 to 20 carbon atoms is preferable. Examples thereof include methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-, m-, p-phenylene, m-, p-xylene, and bis(phenylene)-methane.

[0142] In the formula (i), R 1 , R 4 is a hydrocarbon group having 1 to 10 carbon atoms, R 1 , R 4 may be the same or different from each other. In the formula (i), R 2 , R 5 is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R 2 , R 5 may be the same or different from each other. In the formula (i), R 3is a hydrocarbon group having 1 to 10 carbon atoms, or a structure represented by the following formula (ii): R 1 , R 2 , R 3 may be bonded to each other to form a cyclic structure. Also, R 3 When R is a hydrocarbon group, R may be bonded to R to form a cyclic structure. 3 The N bonded to R may be directly bonded to the N bonded to R. In the above formula (i), n is an integer of 1 or more, and m is 0 or an integer of 1 or more.

[0143] [ka]

[0144] In the formula (ii), R 1 , R 2 is R in the formula (i). 1 , R 2 is defined similarly to R 1 , R 2 may be the same or different from each other.

[0145] [ka]

[0146] In formula (A), R 1 ~R 4 each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms; R 5 represents an alkylene group having 1 to 10 carbon atoms; R 6 represents an alkylene group having 1 to 20 carbon atoms. m represents an integer of 1 or 2, n represents an integer of 2 or 3, and (m+n) represents an integer of 4 or more. 1 ~R 4 are each independent.

[0147] [ka]

[0148] In formula (B), R 1 ~R 6 each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms; R 7 ~R 9 each independently represents an alkylene group having 1 to 20 carbon atoms. m, n, and l each independently represent an integer of 1 to 3, and (m+n+l) represents an integer of 4 or more. 1 ~R 6 are each independent.

[0149] [ka]

[0150] In formula (C), R 12 ~R 14 each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms; R 15 ~R 18 , and R 20 each independently represents an alkyl group having 1 to 20 carbon atoms; R 19 and R 22 each independently represents an alkylene group having 1 to 20 carbon atoms; R 21 represents an alkyl group having 1 to 20 carbon atoms or a trialkylsilyl group. m represents an integer of 1 to 3; p represents 1 or 2. R when there are multiple of each 12 ~R 22 , m, and p are each independent and may be the same or different. i represents an integer of 0 to 6, j represents an integer of 0 to 6, k represents an integer of 0 to 6, and (i+j+k) is an integer of 4 to 10. A represents a hydrocarbon group having 1 to 20 carbon atoms, or an organic group having at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a sulfur atom, and a phosphorus atom and having no active hydrogen.

[0151] The coupling agent having a nitrogen atom-containing group represented by the formula (A) is not limited to the following, but examples thereof include 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silacycloheptane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, Examples of such silacyclopentane include 2,2-diethoxy-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silacyclopentane, 2-methoxy,2-methyl-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2-ethoxy,2-ethyl-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2-methoxy,2-methyl-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, and 2-ethoxy,2-ethyl-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silacyclopentane.

[0152] Among these, from the viewpoints of reactivity and interaction between the functional group of the coupling agent having a nitrogen atom-containing group and an inorganic filler such as silica, and from the viewpoint of processability, those in which m is 2 and n is 3 are preferred. Specifically, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane and 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane are preferred.

[0153] The reaction temperature, reaction time, and the like when reacting the coupling agent having the nitrogen atom-containing group represented by the formula (A) with the active terminal of the polymer are not particularly limited, but it is preferable to react at 0° C. or higher and 120° C. or lower for 30 seconds or longer.

[0154] The total number of moles of alkoxy groups bonded to silyl groups in the coupling agent compound having a nitrogen atom-containing group represented by formula (A) is preferably in the range of 0.6 to 3.0 times the number of moles of the alkali metal compound and / or alkaline earth metal compound added as the polymerization initiator, more preferably in the range of 0.8 to 2.5 times, and even more preferably in the range of 0.8 to 2.0 times. From the viewpoint of obtaining a sufficient modification rate, molecular weight, and branched structure of the obtained branched conjugated diene polymer, it is preferable to set it to 0.6 times or more, and from the viewpoint of the cost of the coupling agent, it is preferable to couple the polymer terminals with each other to obtain a branched conjugated diene polymer component in order to improve processability, and it is preferable to set it to 3.0 times or less.

[0155] The number of moles of the polymerization initiator is preferably 3.0 times or more, more preferably 4.0 times or more, by mole relative to the number of moles of the coupling agent having a nitrogen atom-containing group represented by the formula (A).

[0156] Coupling agents having a nitrogen atom-containing group represented by formula (B) include, but are not limited to, tris(3-trimethoxysilylpropyl)amine, tris(3-methyldimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-methyldiethoxysilylpropyl)amine, tris(trimethoxysilylmethyl)amine, tris(2-trimethoxysilylethyl)amine, and tris(4-trimethoxysilylbutyl)amine.

[0157] Among these, from the viewpoint of reactivity and interaction between the functional group of the coupling agent and an inorganic filler such as silica, and from the viewpoint of processability, it is preferable that n, m, and 1 in the formula (B) all represent 3. Preferable specific examples include tris(3-trimethoxysilylpropyl)amine and tris(3-triethoxysilylpropyl)amine.

[0158] The reaction temperature, reaction time, and the like when reacting the coupling agent having the nitrogen atom-containing group represented by the formula (B) with the active terminal of the branched conjugated diene polymer obtained in the branching step are not particularly limited, but it is preferable to react at 0° C. or higher and 120° C. or lower for 30 seconds or longer.

[0159] The total number of moles of alkoxy groups bonded to silyl groups in the coupling agent compound represented by formula (B) is preferably in the range of 0.6 to 3.0 times the number of moles of lithium constituting the above-mentioned polymerization initiator, more preferably in the range of 0.8 to 2.5 times, and even more preferably in the range of 0.8 to 2.0 times. In order to obtain a sufficient modification rate, molecular weight, and branched structure in the branched conjugated diene polymer obtained by the production method of this embodiment, it is preferably 0.6 times or more, and in order to improve processability, it is preferable to couple the polymer terminals to each other to obtain a branched conjugated diene polymer component, and in terms of the cost of the coupling agent, it is preferably 3.0 times or less.

[0160] The number of moles of the polymerization initiator is preferably 4.0 times or more, more preferably 5.0 times or more, by mole relative to the number of moles of the coupling agent having a nitrogen atom-containing group represented by the formula (B) above.

[0161] In the above formula (C), A is preferably represented by any one of the following general formulae (II) to (V).

[0162] [ka]

[0163] In formula (II), B 1 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. When a plurality of B1's are present, they are each independent.

[0164] [ka]

[0165] In formula (III), B 2 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms; B 3 represents an alkyl group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. 2 and B. 3 are each independent.

[0166] [ka]

[0167] In formula (IV), B 4 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. 4 are each independent.

[0168] [ka]

[0169] In formula (V), B 5 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. 5 are each independent.

[0170] In the formula (C), when A is represented by formula (II), examples of the coupling agent having a nitrogen atom-containing group include, but are not limited to, tris(3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)amine, and the like. tris(3-ethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, and bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)amine.

[0171] In addition, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, Examples of the silylpropylamine include panediamine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, and tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine.

[0172] In addition, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris[ 3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-triethoxysilylpropyl)-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1 -aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, and bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine.

[0173] Further examples thereof include tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, and bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane.

[0174] In addition, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-trimethoxysilyl propyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane.

[0175] In addition, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-triethoxysilylpropyl)-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl) tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1 -sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, methylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, and pentakis(3-trimethoxysilylpropyl)-diethylenetriamine.

[0176] In the formula (C), when A is represented by formula (III), examples of the coupling agent having a nitrogen atom-containing group include, but are not limited to, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tris(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-triethoxysilylpropyl)-[3-(2,2- diethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, N1,N1'-(propane-1,3-diyl)bis(N1-methyl-N3,N3-bis(3-(trimethoxysilyl)propyl)-1,3-propanediamine), and N1-(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N1-methyl-N3-(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N3-(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0177] In the formula (C), when A is represented by formula (IV), examples of the coupling agent having a nitrogen atom-containing group include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, (3-trimethoxysilyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane silane, bis[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silane bis[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-bis(3-trimethoxysilylpropyl)silane, and bis(3-trimethoxysilylpropyl)-bis[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]silane.

[0178] In the formula (C) above, when A is represented by formula (V), examples of the coupling agent having a nitrogen atom-containing group include, but are not limited to, 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-(2,2-dimethoxy-1-aza-2-silacyclopentane)propane and 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane.

[0179] In the formula (C), A is preferably represented by formula (II) or formula (III), and k is 0.

[0180] Coupling agents having such a nitrogen atom-containing group tend to be easily available, and when the branched conjugated diene polymer obtained by the production method of this embodiment is vulcanized, the abrasion resistance and low hysteresis loss performance tend to be superior. Coupling agents having such a nitrogen atom-containing group include, but are not limited to, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis ... tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, and bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trismethoxysilylpropyl)-methyl-1,3-propanediamine.

[0181] In the formula (C), A is more preferably represented by formula (II) or formula (III), k represents 0, and in formula (II) or formula (III), a represents an integer of 2 to 10. This tends to result in better abrasion resistance and low hysteresis loss performance when vulcanized. Examples of such coupling agents having a nitrogen atom-containing group include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N 1 -(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -Methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3 -(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0182] The amount of the compound represented by formula (C) added as a coupling agent having a nitrogen atom-containing group can be adjusted so that the reaction is carried out in a desired stoichiometric ratio of the number of moles of the branched conjugated diene polymer to the number of moles of the coupling agent, which tends to achieve a desired highly branched star structure.

[0183] The number of moles of the polymerization initiator is preferably 5.0 times or more, more preferably 6.0 times or more, by mole relative to the number of moles of the coupling agent having a nitrogen atom-containing group represented by the above formula (C).

[0184] In this case, in formula (C), the number of functional groups of the coupling agent ((m-1)xi+pxj+k) is preferably an integer of 5-10, and more preferably an integer of 6-10.

[0185] In the branched conjugated diene polymer obtained by the production method of this embodiment, the proportion of the polymer having a nitrogen atom-containing group in the polymer is represented by a modification rate. The modification rate is preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, still more preferably 75% by mass or more, still more preferably 80% by mass or more, and particularly preferably 82% by mass or more. By setting the modification rate to 60% by mass or more, the processability when vulcanized is excellent, and the vulcanized product tends to have better abrasion resistance and low hysteresis loss performance.

[0186] <Polymerization terminator process> In the method for producing a branched conjugated diene polymer of the present embodiment, a reaction step can be carried out in which the above-mentioned coupling agent or polymerization terminator is reacted with the active terminal of the conjugated diene polymer obtained through the above-mentioned polymerization step and branching step. As the polymerization terminating step, for example, a polymerization terminating step performed using a bifunctional reactive compound on the active terminal of the conjugated diene polymer, or a polymerization terminating step performed using a polymerization terminating agent having a nitrogen atom-containing group (hereinafter, these may be collectively referred to as "polymerization terminating agent") is preferable.

[0187] In the polymerization terminating step, for example, the active terminal of the polymer obtained in the branching step described above is subjected to a polymerization terminating reaction with a bifunctional reactive compound or a polymerization terminator having a nitrogen atom-containing group, to obtain the target branched conjugated diene-based polymer.

[0188] [Bifunctional reactive compounds] In the method for producing a branched conjugated diene-based polymer of the present embodiment, the bifunctional reactive compound used in the polymerization termination step may have any structure, but is preferably a bifunctional reactive compound having a silicon atom.

[0189] [Polymerization terminator having nitrogen atom-containing group] In the method for producing a branched conjugated diene polymer of the present embodiment, the structure of the polymerization terminator having a nitrogen atom-containing group used in the polymerization termination step is not particularly limited, but it is preferable that the polymerization terminator has a functional group that reacts with the conjugated diene polymer.

[0190] As the polymerization terminator having a nitrogen atom-containing group, from the viewpoint of improving fuel efficiency performance, an alkoxy compound having a nitrogen atom-containing group is preferred. Examples of the polymerization terminator having a nitrogen atom-containing group include 3-(N,N-dimethylaminopropyl)dimethoxymethylsilane, 3-(N,N-diethylaminopropyl)dimethoxymethylsilane, 3-(N,N-dipropylaminopropyl)dimethoxymethylsilane, 3-(N,N-dimethylaminopropyl)diethoxymethylsilane, 3-(N,N-diethylaminopropyl)diethoxymethylsilane, 3-(N,N-dipropylaminopropyl)diethoxymethylsilane, 3-(N,N-dimethylaminopropyl)dimethoxyethylsilane, 3-(N,N-diethylaminopropyl)dimethoxyethylsilane, 3-(N,N-dipropylaminopropyl)dimethoxyethylsilane, 3-(N,N-dimethylaminopropyl)diethoxyethylsilane, 3-(N,N-diethylaminopropyl)diethoxyethylsilane, 3-(N,N-dipropylaminopropyl)diethoxyethylsilane, and the like.

[0191] (Branched conjugated diene polymer) The branched conjugated diene polymer obtained through the above-mentioned polymerization step, branching step, and reaction step by the production method of this embodiment is a polymer of a conjugated diene compound, or a copolymer of a conjugated diene compound and an aromatic vinyl compound, or preferably a copolymer of these with a nitrogen atom-containing vinyl compound, and has a main chain branched structure derived from a styrene derivative, which is a branching agent, in the polymer main chain. The branched structure of the branched conjugated diene polymer of this embodiment preferably has 8 to 36 branches, more preferably has 10 to 24 branches, and even more preferably has 12 to 20 branches. The total number of branching points in the branched conjugated diene polymer obtained by the production method of this embodiment is preferably 2 or more, more preferably 3 or more, even more preferably 4 or more, and even more preferably 5 or more. When the branched structure and the total number of branching points are within the above ranges, the processability, fuel economy, and abrasion resistance tend to be excellent. In order to construct a branched conjugated diene polymer having a branched structure with 8 to 36 branches and, in the case of a modified polymer, a total number of branching points of 2 to 15, it is necessary to use a branching agent with a molar ratio of 1 / 2 or less and 1 / 100 or more of that of the polymerization initiator, and a coupling agent with 3 or more functional groups. In the case of a polymer that does not require modification, the branching point may be 1 or more. In order to construct a branched structure having 8 to 36 branches and a total number of branching points of 3 to 12, it is preferable to use a branching agent having a molar ratio of 1 / 3 or less and 1 / 50 or more of the polymerization initiator and a coupling agent having 4 or more functional groups. In order to construct a branched structure having 10 to 24 branches and a total number of branching points of 4 to 10, it is preferable to use a branching agent having a molar ratio of 1 / 6 or less and 1 / 25 or more of the polymerization initiator and a coupling agent having 5 or more functional groups. In order to construct a branched structure having 12 to 20 branches and a total number of branching points of 5 to 9, it is preferable to use a branching agent having a molar ratio of 1 / 8 or less and 1 / 12 or more of that of the polymerization initiator and a coupling agent having 6 or more functional groups.

[0192] (Condensation reaction process) In the method for producing a branched conjugated diene polymer of the present embodiment, a condensation reaction step of carrying out a condensation reaction in the presence of a condensation promoter may be carried out after the above-mentioned coupling step or before the coupling step.

[0193] (Hydrogenation process) In the method for producing a branched conjugated diene polymer of the present embodiment, a hydrogenation step of hydrogenating the conjugated diene portion may be carried out. The method for hydrogenating the conjugated diene portion of the conjugated diene polymer is not particularly limited, and any known method can be used. A suitable hydrogenation method is to blow gaseous hydrogen into a polymer solution in the presence of a catalyst. The catalyst is not particularly limited, but examples thereof include heterogeneous catalysts such as catalysts in which precious metals are supported on porous inorganic materials; catalysts in which salts of nickel, cobalt, etc. are solubilized and reacted with organoaluminum, etc.; and homogeneous catalysts such as catalysts using metallocenes such as titanocene. Among these, titanocene catalysts are preferred from the viewpoint of being able to select mild hydrogenation conditions. Hydrogenation of aromatic groups can also be carried out by using a catalyst supported on a precious metal.

[0194] Examples of the hydrogenation catalyst include, but are not limited to, (1) supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, Ru, etc. are supported on carbon, silica, alumina, diatomaceous earth, etc., (2) so-called Ziegler-type hydrogenation catalysts using transition metal salts such as organic acid salts or acetylacetone salts of Ni, Co, Fe, Cr, etc. and reducing agents such as organoaluminum, and (3) so-called organometallic complexes such as organometallic compounds of Ti, Ru, Rh, Zr, etc. Furthermore, examples of the hydrogenation catalyst include, but are not limited to, known hydrogenation catalysts described in JP-B-42-8704, JP-B-43-6636, JP-B-63-4841, JP-B-1-37970, JP-B-1-53851, JP-B-2-9041, and JP-A-8-109219. Preferred hydrogenation catalysts include a reaction mixture of a titanocene compound and a reducing organometallic compound.

[0195] (Deactivator and neutralizer addition process) In the method for producing a branched conjugated diene polymer of this embodiment, after the above-mentioned coupling step, a deactivator, a neutralizer, and the like may be added to the polymer solution, if necessary. The quenching agent is not limited to the following, but examples thereof include water; alcohols such as methanol, ethanol, isopropanol, and the like; and the like. Examples of neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a highly branched carboxylic acid mixture having 9 to 11 carbon atoms, with the majority having 10 carbon atoms); aqueous solutions of inorganic acids, and carbon dioxide gas.

[0196] (rubber stabilizer addition process) In the method for producing a branched conjugated diene-based polymer of the present embodiment, it is preferable to add a rubber stabilizer from the viewpoint of preventing gel formation after polymerization and improving stability during processing. The rubber stabilizer is not limited to the following ones, and known ones can be used. For example, antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol are preferred.

[0197] (rubber softener addition process) In the method for producing a branched conjugated diene polymer of the present embodiment, from the viewpoint of further improving the productivity of the branched conjugated diene polymer and the processability when a filler or the like is blended to form a resin composition, a rubber softener can be added as necessary. The rubber softener is not particularly limited, but examples thereof include extender oil, liquid rubber, and resin. The method of adding a rubber softener to a branched conjugated diene polymer is not limited to the following, but a preferred method is to add a rubber softener to a branched conjugated diene polymer solution, mix, and remove the solvent from the resulting polymer solution containing the rubber softener.

[0198] Examples of preferred extender oils include aromatic oils, naphthenic oils, and paraffinic oils. Among these, aromatic substitute oils having a polycyclic aromatic (PCA) content of 3% by mass or less according to the IP346 method are preferred from the viewpoints of environmental safety, oil bleeding prevention, and wet grip properties. Examples of aromatic substitute oils include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts) as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999). Preferred liquid rubbers include, but are not limited to, liquid polybutadiene, liquid styrene-butadiene rubber, and the like. The effects of adding liquid rubber include the ability to improve the processability of a resin composition containing a branched conjugated diene polymer and a filler, etc., and the ability to shift the glass transition temperature of the resin composition to a lower temperature, which tends to improve the abrasion resistance, low hysteresis loss, and low-temperature properties of a vulcanized product. Resins as rubber softeners include, but are not limited to, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including paulownia oil resins), tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic / aromatic hydrocarbon resins, coumarin-indene resins, phenolic resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, monoolefin oligomers, diolefin oligomers, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated paulownia oil resins, hydrogenated oil resins, esters of hydrogenated oil resins and monofunctional or polyfunctional alcohols, etc. These resins may be used alone or in combination of two or more. When hydrogenating, all unsaturated groups may be hydrogenated, or some may be left. Effects of adding a resin as a rubber softener include improving the processability of a resin composition obtained by blending a branched conjugated diene polymer with a filler or the like, tending to improve the breaking strength of a vulcanized product, and tending to improve wet skid resistance by shifting the glass transition temperature of the resin composition to a higher temperature.

[0199] The amount of the rubber softener, such as an extender oil, liquid rubber, or resin, added is not particularly limited, but is preferably 1 part by mass or more and 60 parts by mass or less, more preferably 5 parts by mass or more and 50 parts by mass or less, and even more preferably 10 parts by mass or more and 37.5 parts by mass or less, relative to 100 parts by mass of the branched conjugated diene-based polymer obtained by the production method of the present embodiment. When the rubber softener is added within the above range, the processability of a resin composition obtained by blending the branched conjugated diene-based polymer obtained by the production method of the present embodiment with a filler or the like becomes good, and the breaking strength and abrasion resistance of a vulcanizate tend to be good.

[0200] (Desolvation process) In the method for producing a branched conjugated diene polymer of the present embodiment, a known method can be used to obtain the obtained branched conjugated diene polymer from the polymer solution. The method is not particularly limited, but examples thereof include a method of separating the solvent by steam stripping or the like, filtering the polymer, and then dehydrating and drying it to obtain the polymer, a method of concentrating the polymer in a flashing tank and further devolatilizing the polymer with a vent extruder or the like, and a method of directly devolatilizing the polymer with a drum dryer or the like.

[0201] [Rubber composition and method for producing rubber composition] The rubber composition of the present embodiment contains a rubber component containing 10% by mass or more of the branched conjugated diene-based polymer produced by the production method of the present embodiment described above, and 5.0 parts by mass or more and 150 parts by mass or less of a filler per 100 parts by mass of the rubber component. The method for producing the rubber composition of the present embodiment includes the steps of obtaining a branched conjugated diene polymer by the above-described production method, obtaining a rubber component containing 10% by mass or more of the branched conjugated diene polymer, and incorporating 5.0 parts by mass or more and 150 parts by mass or less of a filler per 100 parts by mass of the rubber component. Furthermore, by containing 10% by mass of the branched conjugated diene polymer obtained by the production method of this embodiment in the rubber component, it is possible to improve fuel economy performance, processability, and abrasion resistance.

[0202] The filler preferably includes a silica-based inorganic filler. By dispersing a silica-based inorganic filler as a filler, the rubber composition tends to have excellent processability when vulcanized, and the vulcanized product tends to have an excellent balance between abrasion resistance, breaking strength, and low hysteresis loss and wet skid resistance. The rubber composition preferably contains a silica-based inorganic filler even when it is used for vulcanized rubber applications such as automobile parts such as tires and anti-vibration rubbers, and shoes.

[0203] The rubber composition of the present embodiment is obtained by mixing a rubber component containing 10% by mass or more of the branched conjugated diene-based polymer obtained by the above-mentioned production method with the filler. The rubber component may contain a rubber-like polymer (hereinafter simply referred to as a "rubber-like polymer") other than the above-mentioned branched conjugated diene-based polymer. Examples of such rubber-like polymers include, but are not limited to, conjugated diene polymers or hydrogenated products thereof, random copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof, block copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof, and others include non-diene polymers and natural rubber.

[0204] Examples of rubber-like polymers include, but are not limited to, styrene-based elastomers such as butadiene rubber or hydrogenated products thereof, isoprene rubber or hydrogenated products thereof, styrene-butadiene rubber or hydrogenated products thereof, styrene-butadiene block copolymer or hydrogenated products thereof, and styrene-isoprene block copolymer or hydrogenated products thereof, and acrylonitrile-butadiene rubber or hydrogenated products thereof.

[0205] Examples of non-diene polymers include, but are not limited to, olefin elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylate-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

[0206] Examples of natural rubber include, but are not limited to, smoked sheets such as RSS3 to 5, SMR, and epoxidized natural rubber.

[0207] The above-mentioned various rubber-like polymers may be modified rubbers to which a polar functional group such as a hydroxyl group, an amino group, etc. When used for tires, butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber are preferably used.

[0208] From the viewpoint of the balance between various performances and processing characteristics of the resin composition, the weight average molecular weight of the rubber-like polymer is preferably from 2000 to 2,000,000, and more preferably from 5000 to 1,500,000. Also, a low molecular weight rubber-like polymer, so-called liquid rubber, can be used. These rubber-like polymers may be used alone or in combination of two or more.

[0209] When the rubber composition using the branched conjugated diene polymer obtained by the production method of this embodiment is used as a rubber composition containing the above-mentioned rubbery polymer, the content ratio (mass ratio) of the above-mentioned branched conjugated diene polymer to the rubbery polymer (above-mentioned branched conjugated diene polymer / rubbery polymer) is preferably 10 / 90 or more and 100 / 0 or less, more preferably 20 / 80 or more and 90 / 10 or less, and even more preferably 50 / 50 or more and 80 / 20 or less. Therefore, the rubber component contains the above-mentioned branched conjugated diene polymer in an amount of preferably 10% by mass or more and 100% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less, based on the total amount (100% by mass) of the rubber component.

[0210] By setting the content ratio of (branched conjugated diene polymer / rubber-like polymer) within the above range, the abrasion resistance and breaking strength of the vulcanized product tend to be excellent, and the balance between low hysteresis loss and wet skid resistance also tends to be good.

[0211] The filler contained in the rubber composition is not limited to the following, but examples thereof include, in addition to the silica-based inorganic filler, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferred. The fillers may be used alone or in combination of two or more. The content of the filler in the rubber composition is 5.0 parts by mass or more and 150 parts by mass or less, preferably 20 parts by mass or more and 100 parts by mass or less, and more preferably 30 parts by mass or more and 90 parts by mass or less, based on 100 parts by mass of the rubber component containing the branched conjugated diene-based polymer. In the rubber composition, the content of the filler is 5.0 parts by mass or more per 100 parts by mass of the rubber component from the viewpoint of expressing the effect of adding the filler, and is 150 parts by mass or less per 100 parts by mass of the rubber component from the viewpoint of sufficiently dispersing the filler and making the processability and mechanical strength of the rubber composition practically sufficient.

[0212] The silica-based inorganic filler is not particularly limited and any known filler can be used. 2 or Si 3 Solid particles containing Al as a constituent unit are preferred, and SiO 2 or Si 3 More preferred are solid particles containing Al as the main component of the structural units. Here, the main component refers to a component contained in the silica-based inorganic filler at 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0213] Examples of silica-based inorganic fillers include, but are not limited to, inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, glass fiber, etc. Other examples include silica-based inorganic fillers whose surfaces have been hydrophobized, and mixtures of silica-based inorganic fillers and inorganic fillers other than silica-based fillers. Among these, silica and glass fiber are preferred from the viewpoints of strength, abrasion resistance, and the like, and silica is more preferred. Examples of silica include dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferred from the viewpoint of excellent balance between the effect of improving fracture strength and wet skid resistance.

[0214] From the viewpoint of obtaining practically satisfactory abrasion resistance and breaking strength in a rubber composition, the nitrogen adsorption specific surface area of ​​the silica-based inorganic filler determined by the BET adsorption method is 100 m 2 / g or more 300m 2 / g or less, and 2 / g or more 250m 2 It is more preferable that the molecular weight is not more than 1 / g. If necessary, a relatively small specific surface area (e.g., a specific surface area of ​​200 m 2 / g or less) and silica-based inorganic fillers with a relatively large specific surface area (e.g., 200 m 2 / g or more) in combination with a silica-based inorganic filler. In particular, those with a relatively large specific surface area (e.g., 200 m 2In the case where a silica-based inorganic filler (having a silica content of 100% or more per 1000 g / g or more) is used, the rubber composition containing the branched conjugated diene polymer described above improves the dispersibility of silica, and is particularly effective in improving abrasion resistance, and tends to achieve a high level of balance between good fracture strength and low hysteresis loss.

[0215] The content of the silica-based inorganic filler in the rubber composition is preferably 5.0 parts by mass or more and 150 parts by mass or less, and more preferably 20 parts by mass or more and 100 parts by mass or less, per 100 parts by mass of the rubber component containing the branched conjugated diene polymer obtained by the production method of this embodiment. The content of the silica-based inorganic filler in the rubber composition is preferably 5.0 parts by mass or more per 100 parts by mass of the rubber component from the viewpoint of exhibiting the effect of adding the silica-based inorganic filler, and is preferably 150 parts by mass or less per 100 parts by mass of the rubber component from the viewpoint of sufficiently dispersing the silica-based inorganic filler and making the processability and mechanical strength of the rubber composition practically sufficient.

[0216] The carbon black is not limited to the following, but examples thereof include carbon blacks of various classes such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon blacks having a nitrogen adsorption specific surface area of ​​50 m 2 / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferred.

[0217] The content of carbon black in the rubber composition is preferably 0.5 parts by mass or more and 100 parts by mass or less, more preferably 3.0 parts by mass or more and 100 parts by mass or less, and even more preferably 5.0 parts by mass or more and 50 parts by mass or less, per 100 parts by mass of the rubber component containing the branched conjugated diene polymer obtained by the production method of this embodiment. In the rubber composition, the content of carbon black is preferably 0.5 parts by mass or more per 100 parts by mass of the rubber component from the viewpoint of realizing the performance required for applications such as tires, such as dry grip performance and electrical conductivity, and is preferably 100 parts by mass or less per 100 parts by mass of the rubber component from the viewpoint of dispersibility.

[0218] Metal oxide refers to solid particles whose main component is a structural unit represented by the chemical formula MxOy (M represents a metal atom, and x and y each independently represent an integer of 1 to 6).

[0219] Examples of metal oxides include, but are not limited to, alumina, titanium oxide, magnesium oxide, and zinc oxide.

[0220] Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0221] In the method for producing the rubber composition of the present embodiment, a step of incorporating a silane coupling agent may be carried out. The silane coupling agent has a function of strengthening the interaction between the rubber component and the inorganic filler. Specifically, it has a group having affinity or binding properties for both the rubber component and the silica-based inorganic filler, and is preferably a compound having a sulfur bond portion and an alkoxysilyl group or silanol group portion in one molecule. Examples of such compounds include, but are not limited to, bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0222] In the rubber composition, the content of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1.0 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the above-mentioned filler. When the content of the silane coupling agent is within the above range, the above-mentioned addition effect of the silane coupling agent tends to be more remarkable.

[0223] The rubber composition may contain a rubber softener from the viewpoint of improving the processability thereof. The amount of rubber softener added is expressed as the total amount including the amount of rubber softener previously contained in the branched conjugated diene polymer or other rubber-like polymers and the amount of rubber softener added when producing the rubber composition, per 100 parts by mass of the rubber component containing the branched conjugated diene polymer obtained by the production method of the present embodiment. As the rubber softener, mineral oil or a liquid or low molecular weight synthetic softener is preferable. Mineral oil-based rubber softeners, called process oils or extender oils, which are used to soften rubber, increase its volume, and improve its processability, are mixtures of aromatic rings, naphthene rings, and paraffin chains, and those in which the carbon number of the paraffin chain is 50% or more of the total carbon are called paraffin-based, those in which the carbon number of the naphthene ring is 30% to 45% of the total carbon are called naphthene-based, and those in which the aromatic carbon number is more than 30% of the total carbon are called aromatic. When the branched conjugated diene polymer of this embodiment is a copolymer of a conjugated diene compound and a vinyl aromatic compound, it is preferable to use a rubber softener having a moderate aromatic content, since it tends to be compatible with the branched conjugated diene polymer. In the rubber composition, the content of the rubber softener is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass, and even more preferably 30 to 90 parts by mass, per 100 parts by mass of the rubber component. By making the content of the rubber softener 100 parts by mass or less per 100 parts by mass of the rubber component, bleeding out is suppressed, and stickiness of the surface of the rubber composition tends to be suppressed.

[0224] The method for mixing the branched conjugated diene polymer obtained by the production method of the present embodiment with additives such as other rubber-like polymers, silica-based inorganic fillers, carbon black and other fillers, silane coupling agents, and rubber softeners is not limited to the following, but examples thereof include a melt-kneading method using a general mixer such as an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, or a multi-screw extruder, and a method in which the components are dissolved and mixed and then the solvent is removed by heating. Among these, the melt kneading method using a roll, a Banbury mixer, a kneader, or an extruder is preferred from the viewpoints of productivity and good kneading properties. In addition, either a method of kneading the rubber component, other fillers, a silane coupling agent, and additives all at once or a method of mixing them in several batches can be applied.

[0225] The rubber composition may be a vulcanized composition that has been vulcanized with a vulcanizing agent. Examples of the vulcanizing agent include, but are not limited to, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Examples of the sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and polymeric polysulfur compounds. In the rubber composition, the content of the vulcanizing agent is preferably 0.01 parts by mass to 20 parts by mass, more preferably 0.1 parts by mass to 15 parts by mass, based on 100 parts by mass of the rubber component. As the vulcanization method, a conventionally known method can be applied, and the vulcanization temperature is preferably 120°C to 200°C, more preferably 140°C to 180°C.

[0226] In vulcanization, a vulcanization accelerator may be used as necessary. As the vulcanization accelerator, a conventionally known material can be used, and examples thereof include, but are not limited to, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Furthermore, the vulcanization aid may include, but is not limited to, zinc oxide and stearic acid. The amount of the vulcanization accelerator is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, based on 100 parts by mass of the rubber component.

[0227] The rubber composition may contain various additives such as other softeners, other fillers, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, and lubricants, in addition to those described above, within the scope of the present embodiment. As the other softening agents, known softening agents can be used. Other fillers include, but are not limited to, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. As the heat resistance stabilizer, antistatic agent, weather resistance stabilizer, antioxidant, colorant, and lubricant, known materials can be used.

[0228] [Tire and tire manufacturing method] The tire of the present embodiment contains the rubber composition of the present embodiment described above. The method for producing a tire according to the present embodiment includes a step of obtaining a branched conjugated diene polymer by the production method according to the present embodiment, a step of obtaining a rubber composition containing the branched conjugated diene polymer, and a step of molding the rubber composition. The rubber composition containing the branched conjugated diene polymer obtained by the production method of the present embodiment described above is suitably used as a rubber composition for tires.

[0229] The rubber composition for tires can be used in various tire parts such as treads, carcasses, sidewalls, and beads of various tires such as fuel-efficient tires, all-season tires, high-performance tires, and studless tires, although the tire rubber composition is not limited thereto. The rubber composition for tires containing the branched conjugated diene-based polymer of the present embodiment has an excellent balance between abrasion resistance, breaking strength, low hysteresis loss and wet skid resistance when vulcanized, and is therefore suitably used for the treads of fuel-saving tires and high-performance tires. EXAMPLES

[0230] Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited in any way to the following examples and comparative examples. [First embodiment] As a first example, the present embodiment will be described in detail by giving a specific example and a comparative example. Hereinafter, a conjugated diene polymer coupled with a nitrogen atom-containing modifier will be referred to as a "coupled conjugated diene polymer". Moreover, the conjugated diene polymer in an unmodified state is referred to as an "unmodified conjugated diene polymer." In the tables, it is simply referred to as a "conjugated diene polymer." Furthermore, a conjugated diene polymer having a branched structure is referred to as a "branched conjugated diene polymer." Various physical properties in the examples and comparative examples were measured by the methods shown below.

[0231] (Physical property 1) Polymer Mooney viscosity An unmodified conjugated diene polymer or a conjugated diene polymer coupled with a nitrogen atom-containing modifier (hereinafter also referred to as a "coupled conjugated diene polymer") was used as a sample, and the Mooney viscosity was measured using a Mooney viscometer (manufactured by Ueshima Seisakusho Co., Ltd., product name "VR1132") using an L-type rotor in accordance with ISO 289. The measurement temperature was 110°C when an unmodified conjugated diene polymer (simply referred to as conjugated diene polymer in the table) was used as the sample, and 100°C when a coupled conjugated diene polymer was used as the sample. First, the sample was preheated at the test temperature for 1 minute, and then the rotor was rotated at 2 rpm. The torque was measured after 4 minutes to determine the Mooney viscosity (ML (1+4) ) was decided.

[0232] (Physical property 2) Mooney relaxation rate A coupling conjugated diene polymer was used as a sample, and the Mooney viscosity was measured using a Mooney viscometer (manufactured by Ueshima Seisakusho Co., Ltd. under the trade name "VR1132") with an L-shaped rotor in accordance with ISO 289. The rotation of the rotor was then immediately stopped, and the torque was recorded in Mooney units every 0.1 seconds for 1.6 to 5 seconds after the rotor was stopped. The slope of the straight line obtained by plotting the torque versus time (seconds) on a double logarithmic scale was determined, and the absolute value of the slope was taken as the Mooney relaxation rate (MSR).

[0233] (Physical property 3) Branching degree (Bn) The branching degree (Bn) of the coupling conjugated diene polymer was measured by a GPC-light scattering method equipped with a viscosity detector as follows. A coupling conjugated diene polymer was used as a sample, and measurements were performed using a gel permeation chromatography (GPC) measuring device (manufactured by Malvern under the trade name "GPCmax VE-2001") in which three columns packed with polystyrene gel were connected together, and three detectors were connected in that order: a light scattering detector, an RI detector, and a viscosity detector (manufactured by Malvern under the trade name "TDA305"). Based on standard polystyrene, the absolute molecular weight was calculated from the measurement results of the light scattering detector and the RI detector, and the intrinsic viscosity was calculated from the measurement results of the RI detector and the viscosity detector. Linear polymer has an intrinsic viscosity [η] = -3.883M 0.771 The shrinkage factor (g') was calculated as the ratio of the intrinsic viscosity corresponding to each molecular weight, where M represents the absolute molecular weight. The obtained shrinkage factor (g') was then used to calculate the branching degree (Bn), defined as g' = 6Bn / [(Bn+1)(Bn+2)]. The eluent used was tetrahydrofuran (hereinafter also referred to as "THF") containing 5 mmol / L triethylamine. The columns used were "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL" manufactured by Tosoh Corporation. 20 mg of the measurement sample was dissolved in 10 mL of THF to prepare a measurement solution, and 100 μL of the measurement solution was injected into a GPC measurement device and measured under conditions of an oven temperature of 40° C. and a THF flow rate of 1 mL / min.

[0234] (Physical property 4) Molecular weight <Measurement condition 1>: Using an unmodified conjugated diene polymer or a coupled conjugated diene polymer as a sample, a chromatogram was measured using a GPC measuring device (manufactured by Tosoh Corporation under the trade name "HLC-8320GPC") in which three columns packed with polystyrene gel were connected together, and an RI detector (manufactured by Tosoh Corporation under the trade name "HLC8020") was used. Based on a calibration curve obtained using standard polystyrene, the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were determined. The eluent used was tetrahydrofuran (THF) containing 5 mmol / L triethylamine. Three columns, Tosoh Corporation's "TSKgel SuperMultiporeHZ-H" (trade name), were connected, and a Tosoh Corporation's "TSKguardcolumn SuperMP(HZ)-H" (trade name) was connected in front of them as a guard column. 10 mg of the measurement sample was dissolved in 10 mL of THF to prepare a measurement solution, and 10 μL of the measurement solution was injected into a GPC measurement device and measured under conditions of an oven temperature of 40° C. and a THF flow rate of 0.35 mL / min. Among the various samples measured under the above measurement condition 1, samples whose molecular weight distribution (Mw / Mn) was less than 1.6 were measured again under the following measurement condition 2. For samples whose molecular weight distribution was 1.6 or more when measured under measurement condition 1, the measured value under measurement condition 1 was used. <Measurement condition 2>: Using an unmodified conjugated diene polymer or a coupled conjugated diene polymer as a sample, a chromatogram was measured using a GPC measuring device having three columns connected together, each column using a polystyrene gel as a packing material, and the weight average molecular weight (Mw) and number average molecular weight (Mn) were determined based on a calibration curve using standard polystyrene. The eluent used was THF containing 5 mmol / L triethylamine. The columns used were the following: guard column: Tosoh Corporation's product name "TSKguardcolumn SuperH-H"; columns: Tosoh Corporation's product names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000". An RI detector (manufactured by Tosoh Corporation under the trade name "HLC8020") was used under the conditions of an oven temperature of 40° C. and a THF flow rate of 0.6 mL / min. 10 mg of a sample to be measured was dissolved in 20 mL of THF to prepare a measurement solution, and 20 μL of the measurement solution was injected into a GPC measurement device for measurement. For samples that were measured under measurement condition 1 and had a molecular weight distribution value of less than 1.6, measurement was performed under measurement condition 2, and the measured value was adopted.

[0235] (Physical property 5) Modification rate The modification rate of the coupling conjugated diene polymer was measured by a column adsorption GPC method as follows. The coupling conjugated diene polymer was used as a sample, and the measurement was carried out by utilizing the adsorption property of the modified basic polymer component in a GPC column packed with silica gel. The amount of a sample solution containing a sample and low molecular weight internal standard polystyrene was adsorbed onto the silica-based column by measuring the difference between the chromatogram measured using a polystyrene-based column and the chromatogram measured using a silica-based column, and the modification rate was calculated. Specifically, it is as follows: Furthermore, for samples that were measured under the above (Physical Property 4) Measurement Condition 1 and had a molecular weight distribution value of 1.6 or more, they were measured under the following Measurement Condition 3, and the measured value was adopted. For samples that were measured under the above (Physical Property 4) Measurement Condition 1 and had a molecular weight distribution value of less than 1.6, they were measured under the following Measurement Condition 4, and the measured value was adopted.

[0236] <Preparation of sample solution>: 10 mg of the sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution. <Measurement condition 3>: GPC measurement conditions using polystyrene columns: A Tosoh Corporation product name "HLC-8320GPC" was used, and 10 μL of the sample solution was injected into the device using THF containing 5 mmol / L triethylamine as the eluent. A chromatogram was obtained using an RI detector under the following conditions: column oven temperature 40°C, THF flow rate 0.35 mL / min. The columns used were three Tosoh Corporation products (TSKgel SuperMultiporeHZ-H) connected together, with a Tosoh Corporation product (TSKguardcolumn SuperMP(HZ)-H) connected in front of them as a guard column.

[0237] <Measurement condition 4>: THF containing 5 mmol / L triethylamine was used as the eluent, and 20 μL of the sample solution was injected into the device for measurement. The columns used were a guard column manufactured by Tosoh Corporation under the trade name "TSKguardcolumn SuperH-H" and columns manufactured by Tosoh Corporation under the trade names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000". Measurement was performed using an RI detector (manufactured by Tosoh Corporation, HLC8020) under conditions of a column oven temperature of 40°C and a THF flow rate of 0.6 mL / min, to obtain a chromatogram.

[0238] GPC measurement conditions using a silica column: A Tosoh Corporation product name "HLC-8320GPC" was used, THF was used as the eluent, 50 μL of the sample solution was injected into the device, and a chromatogram was obtained using an RI detector under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 ml / min. The columns used were Zorbax PSM-1000S, PSM-300S, and PSM-60S, and a guard column "DIOL 4.6 × 12.5 mm 5 micron" was connected to the front of the columns.

[0239] How to calculate the denaturation rate: The total peak area of ​​the chromatogram using the polystyrene column was set as 100, the peak area of ​​the sample was set as P1, the peak area of ​​the standard polystyrene was set as P2, the total peak area of ​​the chromatogram using the silica column was set as 100, the peak area of ​​the sample was set as P3, and the peak area of ​​the standard polystyrene was set as P4, and the modification rate (%) was calculated using the following formula. Denaturation rate (%) = [1-(P2 x P3) / (P1 x P4)] x 100 (where P1+P2=P3+P4=100)

[0240] (Physical property 6) Bound styrene content A coupling conjugated diene polymer not containing a rubber softener was used as a sample, and 100 mg of the sample was dissolved in chloroform up to 100 mL to prepare a measurement sample. The amount of bound styrene (mass%) relative to 100 mass% of the sample coupled conjugated diene polymer was measured based on the amount of absorption of ultraviolet light (around 254 nm) by the phenyl group of styrene (measuring device: Shimadzu Corporation spectrophotometer "UV-2450").

[0241] (Physical property 7) Microstructure of butadiene part (1,2-vinyl bond amount) A coupling conjugated diene polymer not containing a rubber softener was used as a sample, and 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare a measurement sample. Using a solution cell, infrared spectra are recorded from 600 to 1000 cm -1 The absorbance at a predetermined wave number was measured in the range of 1,2-vinyl bond amount (hereinafter, 1,2-vinyl bond amount) (mol%) of the butadiene portion was calculated according to the formula of Hampton's method (method described in R.R. Hampton, Analytical Chemistry 21, 923 (1949)) (measurement device: Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

[0242] (Physical Property 8) Molecular weight (absolute molecular weight) measured by GPC-light scattering method The coupling conjugated diene polymer was used as a sample, and a chromatogram was measured using a GPC-light scattering measuring device in which three columns packed with polystyrene gel were connected, and the weight average molecular weight (Mw-i) was calculated based on the solution viscosity and the light scattering method (also referred to as "absolute molecular weight"). The eluent used was a mixed solution of tetrahydrofuran and triethylamine (THF in TEA: prepared by mixing 5 mL of triethylamine in 1 L of tetrahydrofuran). The columns used were a guard column (manufactured by Tosoh Corporation under the trade name "TSKguardcolumn HHR-H") and columns (manufactured by Tosoh Corporation under the trade names "TSKgel G6000HHR", "TSKgel G5000HHR", and "TSKgel G4000HHR"). A GPC-light scattering measuring device (trade name "Viscotek TDAmax" manufactured by Malvern Instruments) was used under conditions of an oven temperature of 40° C. and a THF flow rate of 1.0 mL / min. 10 mg of the measurement sample was dissolved in 20 mL of THF to prepare a measurement solution, and 200 μL of the measurement solution was injected into the GPC measurement device for measurement.

[0243] [Branched conjugated diene polymer] ( Reference example 1-1) Coupling conjugated diene polymer (sample 1-1) The internal volume is 10 L, and the ratio of internal height (L) to diameter (D) (L / D) is 4.0. The reactor is a tank type reactor with an agitator, an inlet at the bottom and an outlet at the top, and has a jar for temperature control. Two tank-type pressure vessels with a tank cap were connected together as polymerization reactors. 1,3-butadiene, which had been previously dehydrated, was fed at 18.6 g / min, and styrene at 10.0 g / min. The mixture was fed to the inlet of the reactor. In the static mixer installed in the piping that supplies the gas, a gas for inactivating remaining impurities is used. -Butyllithium was added at 0.103mmol / min and mixed, then continuously poured into the bottom of the reactor. In addition, 2,2-bis(2-oxolanyl)propane was added as a polar substance at 0.0 At a rate of 81 mmol / min, 0.143 mmol of n-butyllithium was used as a polymerization initiator. The mixture was fed to the bottom of the first reactor, which was vigorously mixed with an agitator, at a rate of 1 / min. The temperature inside the reactor was kept at 67°C. The temperature was kept at .degree. The polymer solution was continuously withdrawn from the top of the first reactor and continuously poured into the bottom of the second reactor. The reaction was continued at 70°C, and then the mixture was fed to the static mixer from the top of the second unit. When the polymerization is sufficiently stable, 1,3-butadiene and styrene are copolymerized. From the bottom of the second reactive group, trimethoxy(4-vinylphenyl)silane ( In the table, this is abbreviated as "BS-1.") was added at a rate of 0.0190 mmol / min to form a main chain branch structure. The polymerization reaction and branching reaction were carried out to obtain a conjugated diene polymer having the above structure. After the polymerization reaction and the branching reaction were stabilized, the conjugated diene before the addition of the coupling agent was A small amount of the polymer solution was taken out, and the antioxidant (BHT) was adjusted to 0.2 g per 100 g of polymer. After the solvent was removed, the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 1. Next, the polymer solution discharged from the outlet of the reactor was mixed with tetraethoxysilane as a coupling agent. Silane (abbreviated as "A" in the table) was added continuously at a rate of 0.0480 mmol / min. The mixture was mixed using a static mixer and subjected to a coupling reaction. The time it took for the coupling agent to be added to the polymer solution flowing out of the nozzle was 4.8 minutes, and the temperature was The difference between the temperature during the polymerization process and the temperature before adding the coupling agent is 68°C. After the coupling reaction, a small amount of the conjugated diene polymer solution was taken out and added with an antioxidant. (BHT) was added in an amount of 0.2 g per 100 g of polymer, and the solvent was then removed to give a The amount of styrene in the mixture (Physical Properties 6) and the microstructure of the butadiene part (1,2-vinyl bond amount: Physical Properties The results are shown in Table 1. Next, add an antioxidant (BHT) to the polymer solution after the coupling reaction for 100 g of polymer. The amount of n-hexane solution was continuously added at 0.055 g / min so that the amount was 0.2 g per unit time. The coupling reaction was completed. In contrast, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) The mixture was added continuously to a total of 25.0 g and mixed with a static mixer. The solvent is removed by stripping, and a compound represented by the following formula (1) is added to a part of the main chain. It has a four-branched structure derived from a branching agent (hereinafter also referred to as "branching agent structure (1)"), and is coupled A coupling conjugated diene polymer (sample 1) with a three-branched star polymer structure derived from a coupling agent -1). The physical properties of Sample 1-1 are shown in Table 1. The polymer before the addition of the branching agent, the polymer after the addition of the branching agent, and the polymer after the addition of the coupling agent are The molecular weight of the polymer in each process was measured by GPC and the molecular weight was measured by GPC with a viscometer. The structure of the coupling conjugated diene polymer was identified by comparing with the branching degree by the method described below. The structure of each sample was identified in the same manner.

[0244] [ka]

[0245] In formula (1), R 1 represents any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. X 1 is a single bond or an organic group containing any one selected from the group consisting of carbon, hydrogen, nitrogen, sulfur, and oxygen. Y 1 represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. They may be independent and the same or different.

[0246] ( Reference example 1-2) Coupling conjugated diene polymer (sample 1-2) The coupling agent was converted from tetraethoxysilane to 1,2-bis(triethoxysilyl)ethene. (abbreviated as "B" in the table) and the amount added was changed to 0.0360 mmol / min. Outside, Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-2) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-2 are shown in Table 1.

[0247] (Example 1-3) Coupling conjugated diene polymer (sample 1-3) The coupling agent was changed from tetraethoxysilane to 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (abbreviated as "C" in the table), and its addition amount was changed to 0.0360mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-3) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-3 are shown in Table 1.

[0248] (Example 1-4) Coupling conjugated diene polymer (sample 1-4) The coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min, but in the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-4) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-4 are shown in Table 1.

[0249] (Example 1-5) Coupling conjugated diene polymer (sample 1-5) The coupling agent was changed from tetraethoxysilane to tris(3-trimethoxysilylpropyl)amine (abbreviated as "E" in the table) and the amount of the coupling agent was changed to 0.0250mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-5) having a 4-branched structure derived from the branching agent structure (1) in a part of the main chain and a 6-branched star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-5 are shown in Table 1.

[0250] (Example 1-6) Coupling conjugated diene polymer (sample 1-6) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the amount of the coupling agent was changed to 0.0190mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-6) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-6 are shown in Table 1.

[0251] (Example 1-7) Coupling conjugated diene polymer (sample 1-7) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the amount of the coupling agent was changed to 0.0160mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-7) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-7 are shown in Table 1.

[0252] (Example 1-8) Coupling conjugated diene polymer (sample 1-8) The addition rate of 1,3-butadiene was changed from 18.6g / min to 24.3g / min, the addition rate of styrene was changed from 10.0g / min to 4.3g / min, the addition rate of 2,2-bis(2-oxolanyl)propane as a polar substance was changed from 0.081mmol / min to 0.044mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the addition amount was changed to 0.0160mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-8) having a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-8 are shown in Table 1.

[0253] (Example 1-9) Coupling conjugated diene polymer (sample 1-9) The addition rate of 1,3-butadiene was changed from 18.6g / min to 17.1g / min, the addition rate of styrene was changed from 10.0g / min to 11.5g / min, the addition rate of 2,2-bis(2-oxolanyl)propane as a polar substance was changed from 0.081mmol / min to 0.089mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the addition amount was changed to 0.0160mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-9) having a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-9 are shown in Table 2.

[0254] (Example 1-10) Coupling conjugated diene polymer (sample 1-10) The addition rate of polar substance 2,2-bis(2-oxolanyl)propane was changed from 0.081mmol / min to 0.200mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the addition amount was changed to 0.0160mmol / min, but the same procedure as in Example 1-1 was used to obtain a coupling conjugated diene polymer (sample 1-10) having a 4-branch structure derived from the branching agent structure (1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-10 are shown in Table 2.

[0255] ( Reference example 1-11) Coupling conjugated diene polymer (sample 1-11) The branching agent was converted from trimethoxy(4-vinylphenyl)silane to dimethylmethoxy(4-vinyl (BS-2) in the table, and the amount added was 0.0350m mol / min, and the coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilane) (xysilyl)ethane (abbreviated as "B" in the table), and the amount added was 0.0360mmol Except for changing to l / min. Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-11) was obtained, which has a two-branch structure derived from the branching agent structure (1) in a part of the main chain and a four-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-11 are shown in Table 2.

[0256] (Example 1-12) Coupling conjugated diene polymer (sample 1-12) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to dimethylmethoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table), and its addition amount was changed to 0.0350mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-12) having a two-branch structure derived from the branching agent structure (1) in a part of the main chain and a four-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-12 are shown in Table 2.

[0257] (Example 1-13) Coupling conjugated diene polymer (sample 1-13) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to dimethylmethoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table), and its addition amount was changed to 0.0350mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and its addition amount was changed to 0.0160mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-13) having a two-branch structure derived from the branching agent structure (1) in a part of the main chain and an eight-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-13 are shown in Table 2.

[0258] ( Reference example 1-14) Coupling conjugated diene polymer (sample 1-14) Branching agents were prepared from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-(dimethylphenyl)silane) (phenylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table) and its addition The amount was changed to 0.0120 mmol / min, and the coupling agent was changed from tetraethoxysilane to 1, The amount of 2-bis(triethoxysilyl)ethane (abbreviated as "B" in the table) was changed to Except for changing to 0.0360mmol / min, Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-14) was obtained, which has a three-branched structure derived from the branching agent (hereinafter also referred to as "branching agent structure (2)"), which is a compound represented by the following formula (2), in a part of the main chain, and a four-branched star polymer structure derived from the coupling agent. The physical properties of sample 1-14 are shown in Table 2.

[0259] [ka]

[0260] In formula (2), X 2 , X 3 is a single bond or an organic group containing any one selected from the group consisting of carbon, hydrogen, nitrogen, sulfur, and oxygen. Y 2 , Y 3 represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. They may be independent and the same or different.

[0261] (Example 1-15) Coupling conjugated diene polymer (sample 1-15) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table), and the amount added was changed to 0.0120mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and the amount added was changed to 0.0360mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-15) having a three-branched structure derived from the branching agent structure (2) in part of the main chain and a four-branched star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-15 are shown in Table 2.

[0262] (Example 1-16) Coupling conjugated diene polymer (Sample 1-16) A coupling conjugated diene polymer (sample 1-16) having a three-branched structure derived from the branching agent structure (2) in a part of the main chain and an eight-branched star polymer structure derived from the coupling agent was obtained in the same manner as in Example 1-1, except that the branching agent was changed from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table) and the amount added was changed to 0.0120mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) and the amount added was changed to 0.0160mmol / min. The physical properties of sample 1-16 are shown in Table 2.

[0263] ( Reference example 1-17) Coupling conjugated diene polymer (sample 1-17) Branching agents were synthesized from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-trimethoxy (xysilylphenyl)ethylene (abbreviated as "BS-4" in the table), and the amount added was 0. The coupling agent was changed from tetraethoxysilane to 1,2-bis(1,2-diphenylsilane). (triethoxysilyl)ethane (abbreviated as "B" in the table), and the amount added was 0.03 Except for changing to 60mmol / min, Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-17) was obtained, which has a 7-branch structure derived from the branching agent structure (2) in a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-17 are shown in Table 3.

[0264] (Example 1-18) Coupling conjugated diene polymer (sample 1-18) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-trimethoxysilylphenyl)ethylene (abbreviated as "BS-4" in the table), and its addition amount was changed to 0.0210mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min, but in the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-18) having a 7-branch structure derived from the branching agent structure (2) in part of the main chain and a 4-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-18 are shown in Table 3.

[0265] (Example 1-19) Coupling conjugated diene polymer (sample 1-19) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-trimethoxysilylphenyl)ethylene (abbreviated as "BS-4" in the table), and the amount added was changed to 0.0210mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0160mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-19) having a 7-branch structure derived from the branching agent structure (2) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-19 are shown in Table 3.

[0266] ( Reference example 1-20) Coupling conjugated diene polymer (sample 1-20) The branching agent was converted from trimethoxy(4-vinylphenyl)silane to trichloro(4-vinylphenyl)silane. (BS-5) in the table, and the amount added was 0.0190 mmol. / min, and the coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilane) (aryl)ethane (abbreviated as "B" in the table), and the amount added was 0.0360 mmol / min. Other than changing it to Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-20) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-20 are shown in Table 3.

[0267] (Example 1-21) Coupling conjugated diene polymer (sample 1-21) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to trichloro(4-vinylphenyl)silane (abbreviated as "BS-5" in the table), and its addition amount was changed to 0.0190mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min, but in the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-21) having a 4-branch structure derived from the branching agent structure (1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-21 are shown in Table 3.

[0268] (Example 1-22) Coupling conjugated diene polymer (sample 1-22) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to trichloro(4-vinylphenyl)silane (abbreviated as "BS-5" in the table), and its addition amount was changed to 0.0190mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and its addition amount was changed to 0.0160mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-22) having a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-22 are shown in Table 3.

[0269] (Example 1-23) Coupling conjugated diene polymer (sample 1-23) The amount of branching agent trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) added was changed from 0.0190mmol / min to 0.0100mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-23) having a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-23 are shown in Table 3.

[0270] (Example 1-24) Coupling conjugated diene polymer (Sample 1-24) The amount of branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) added was changed from 0.0190mmol / min to 0.0250mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-24) having a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-24 are shown in Table 4.

[0271] (Example 1-25) Coupling conjugated diene polymer (sample 1-25) The amount of branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) added was changed from 0.0190mmol / min to 0.0350mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-25) having a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-25 are shown in Table 4.

[0272] (Example 1-26) Coupling conjugated diene polymer (sample 1-26) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount was changed to 0.0190mmol / min, and the SRAE oil added as a rubber softener was replaced with liquid rubber (Kuraray Co., Ltd. liquid polybutadiene LBR-302). In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-26) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-26 are shown in Table 4.

[0273] (Example 1-27) Coupling conjugated diene polymer (sample 1-27) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount was changed to 0.0190mmol / min, and the SRAE oil added as a rubber softener was replaced with resin (Yasuhara Chemical Co., Ltd., terpene resin YS Resin PX1250). In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-27) having a 4-branch structure derived from the branching agent structure (1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 1-27 are shown in Table 4.

[0274] (Example 1-28) Coupling conjugated diene polymer (sample 1-28) Coupling agent is changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount is changed to 0.0190mmol / min, and naphthenic oil (Nynas naphthenic oil Nytex810) is added instead of SRAE oil added as rubber softener, in the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-28) having a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent is obtained. The physical properties of sample 1-28 are shown in Table 4.

[0275] (Example 1-29) Coupling conjugated diene polymer (Sample 1-29) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount was changed to 0.0190mmol / min, and no rubber softener was added. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-29) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-29 are shown in Table 4.

[0276] (Example 1-30) Coupling conjugated diene polymer (Sample 1-30) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount was changed to 0.0190mmol / min, and the amount of SRAE oil added as a rubber softener was changed from 25.0g to 37.5g per 100g of polymer, but in the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-30) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-30 are shown in Table 4.

[0277] ( Reference example 1-31) Conjugated diene polymer (sample 1-31) When the polymerization is sufficiently stable, trimethoprim is added as a branching agent to the bottom of the second reactive group. 0.0190mmol bis(4-vinylphenyl)silane (abbreviated as "BS-1" in the table). 1 / min, except that no coupling agent was added. Reference example In the same manner as in 1-1, a conjugated diene polymer (sample 1-31) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and does not show a star-shaped coupling structure derived from the coupling agent. The physical properties of sample 1-31 are shown in Table 5.

[0278] ( Reference example 1-32) Coupling conjugated diene polymer (sample 1-32) When the polymerization is sufficiently stable, trimethoprim is added as a branching agent to the bottom of the second reactive group. 0.0190mmol bis(4-vinylphenyl)silane (abbreviated as "BS-1" in the table). The coupling agent was tetraethoxysilane (represented as "A" in the table) at a rate of 1 / min. The amount of added 100 mmol / min was changed from 0.0480 mmol / min to 0.0120 mmol / min. Outside, Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-32) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in part of the main chain and a 3-branch star polymer structure derived from the coupling agent in part. The physical properties of sample 1-32 are shown in Table 5.

[0279] (Example 1-33) Coupling conjugated diene polymer (Sample 1-33) When the polymerization was sufficiently stable, trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added as a branching agent from the bottom of the second reactive group at a rate of 0.0190mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the addition rate was changed to 0.0038mmol / min. In the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-33) was obtained, which has a 4-branched structure derived from the branching agent structure (1) in part of the main chain and a 8-branched star polymer structure derived from the coupling agent in part. The physical properties of sample 1-33 are shown in Table 5.

[0280] ( Reference example 1-34) Coupling conjugated diene polymer (sample 1-34) When the polymerization is sufficiently stable, dimethyl ether is added as a branching agent to the bottom of the second reactive group. Methoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table) at 0.0350 The coupling agent tetraethoxysilane was added at a rate of 0.0 mmol / min. Except for changing from 480mmol / min to 0.0120mmol / min, Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-34) was obtained, which has a bi-branched structure derived from the branching agent structure (1) in part of the main chain and a tri-branched star polymer structure derived from the coupling agent in part. The physical properties of sample 1-34 are shown in Table 5.

[0281] ( Reference example 1-35) Coupling conjugated diene polymer (sample 1-35) When the polymerization is sufficiently stable, the 1,1- Bis(4-(dimethylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table) ) was added at a rate of 0.0120 mmol / min, and the coupling agent tetraethoxysilane was added. Except for changing the amount of amine added from 0.0480mmol / min to 0.0120mmol / min, Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-35) was obtained, which has a tri-branched structure derived from the branching agent structure (2) in part of the main chain and a tri-branched star polymer structure derived from the coupling agent in part. The physical properties of sample 1-35 are shown in Table 5.

[0282] (Example 1-36) Coupling conjugated diene polymer (Sample 1-36) The coupling agent was changed from tetraethoxysilane to 3-(benzylideneamino)propyltriethoxysilane (abbreviated as "G" in the table), and its addition amount was changed to 0.0620mmol / min, but in the same manner as in Example 1-1, a coupling conjugated diene polymer (sample 1-36) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and a 2-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-36 are shown in Table 5.

[0283] ( Reference example 1-37) Coupling conjugated diene polymer (sample 1-37) 1,3-butadiene added to the first reactor from 18.6g / min to 13.95g / min The branching agent and 1,3-butadiene were added at 4.65g from the bottom of the second reaction unit. g / min. Reference example In the same manner as in 1-1, a coupling conjugated diene polymer (sample 1-37) was obtained, which has a 4-branch structure derived from the branching agent structure (1) in a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-37 are shown in Table 5.

[0284] (Example A-1) Coupling conjugated diene polymer (sample A-1) Two tank-type pressure vessels having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and an agitator as a tank-type reactor and a jacket for temperature control were connected together as polymerization reactors. 1,3-butadiene, from which moisture had been removed in advance, was mixed at 14.0 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min. In a static mixer installed in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating remaining impurities was added at 0.103 mmol / min, mixed, and then continuously supplied to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance at a rate of 0.081 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.143 mmol / min were supplied to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the temperature inside the reactor was maintained at 67°C. The polymer solution was continuously withdrawn from the top of the first reactor, continuously fed to the bottom of the second reactor, and the reaction was continued at 70°C, and further fed to a static mixer from the top of the second reactor. When the polymerization was sufficiently stable, 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene (abbreviated as "N-1" in the table) was added as a nitrogen atom-containing vinyl compound from the bottom of the second reactor at a rate of 0.120 mmol / min while copolymerizing 1,3-butadiene and styrene, and trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added as a branching agent at a rate of 0.0190 mmol / min, and in parallel, 1,3-butadiene was added at 4.6 g / min, to perform a polymerization reaction and a branching reaction to obtain a conjugated diene polymer having a main chain branched structure. Furthermore, when the polymerization reaction and the branching reaction became stable, a small amount of the modified branched conjugated diene polymer solution before the addition of the coupling agent was withdrawn, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of polymer, after which the solvent was removed and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 6. Next, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table) was used as a coupling agent and added continuously at an addition rate of 0.0360 mmol / min to the polymer solution discharged from the outlet of the reactor, and the mixture was mixed using a static mixer to carry out a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, the temperature was 68°C, and the difference between the temperature in the polymerization process and the temperature until the coupling agent was added was 2°C. After the coupling reaction, a small amount of the coupling conjugated diene polymer solution was taken out, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of polymer, after which the solvent was removed and the bound styrene content (physical property 6) and the microstructure of the butadiene portion (1,2-vinyl bond content: physical property 7) were measured. The measurement results are shown in Table 6. Next, an antioxidant (BHT) was continuously added to the polymer solution after the coupling reaction at 0.055 g / min (n-hexane solution) so that the amount was 0.2 g per 100 g of polymer, and the coupling reaction was terminated. Simultaneously with the antioxidant, SRAE oil (JOMO Process NC140, manufactured by JX Nippon Oil & Energy Corporation) was continuously added as a rubber softener in an amount of 25.0 g per 100 g of polymer, and mixed with a static mixer. The solvent was removed by steam stripping to obtain a coupled conjugated diene polymer (modified conjugated diene polymer) (sample A-1) having a four-branched structure derived from the branching agent (hereinafter also referred to as "branching agent structure (1)"), which is a compound represented by the above formula (1), in a portion of the main chain and a four-branched star polymer structure derived from the coupling agent. The physical properties of sample A-1 are shown in Table 6. The structure of the coupling conjugated diene polymer was identified by comparing the molecular weight measured by GPC and the branching degree measured by GPC with a viscometer for the polymer before the addition of the branching agent, the polymer after the addition of the branching agent, and the polymer in each step after the addition of the coupling agent. The structure of each sample was similarly identified.

[0285] (Example A-2) Coupling conjugated diene polymer (sample A-2) Two tank-type pressure vessels having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and an agitator as a tank-type reactor and a jacket for temperature control were connected together as polymerization reactors. 1,3-butadiene, from which moisture had been removed in advance, was mixed at 14.0 g / min, styrene at 8.0 g / min, and n-hexane at 175.2 g / min. In a static mixer installed in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating remaining impurities was added at 0.103 mmol / min, mixed, and then continuously supplied to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance at a rate of 0.081 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.143 mmol / min were supplied to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the temperature inside the reactor was maintained at 67°C. The polymer solution was continuously withdrawn from the top of the first reactor and continuously fed to the bottom of the second reactor to continue the reaction at 70°C, and further fed to a static mixer from the top of the second reactor. When the polymerization was sufficiently stable, 1,3-butadiene and styrene were copolymerized while 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene (abbreviated as "N-1" in the table) was added as a nitrogen atom-containing vinyl compound from the bottom of the second reactor at a rate of 0.120 mmol / min, and trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added as a branching agent from the bottom of the second reactor at a rate of 0.0190 mmol / min, and in parallel, 1,3-butadiene was added at 4.6 g / min and styrene was added at 2.0 g / min to perform polymerization and branching reactions to obtain a conjugated diene polymer having a main chain branched structure. When the polymerization reaction and the branching reaction became stable, a small amount of the conjugated diene polymer solution before the addition of the coupling agent was withdrawn, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of polymer, after which the solvent was removed and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 6. Next, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table) was used as a coupling agent and added continuously at an addition rate of 0.0360 mmol / min to the polymer solution discharged from the outlet of the reactor, and the mixture was mixed using a static mixer to carry out a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, the temperature was 68 ° C, and the difference between the temperature in the polymerization process and the temperature before the coupling agent was added was 2 ° C. A small amount of the conjugated diene polymer solution after the coupling reaction was withdrawn, and an antioxidant (BHT) was added so that the amount was 0.2 g per 100 g of polymer, and then the solvent was removed, and the bound styrene amount (physical property 6) and the microstructure of the butadiene portion (1,2-vinyl bond amount: physical property 7) were measured. The measurement results are shown in Table 6. Next, an antioxidant (BHT) was continuously added to the polymer solution after the coupling reaction at 0.055 g / min (n-hexane solution) so that the amount was 0.2 g per 100 g of polymer, and the coupling reaction was terminated. Simultaneously with the antioxidant, SRAE oil (JOMO Process NC140, manufactured by JX Nippon Oil & Energy Corporation) was continuously added as a rubber softener in an amount of 25.0 g per 100 g of polymer, and mixed with a static mixer. The solvent was removed by steam stripping to obtain a coupled conjugated diene polymer (sample A-2) having a four-branched structure derived from the branching agent (hereinafter also referred to as "branching agent structure (1)"), which is a compound represented by the above formula (1), in a portion of the main chain and a four-branched star polymer structure derived from the coupling agent. The physical properties of sample A-2 are shown in Table 6. The structure of the coupled conjugated diene polymer was identified by comparing the molecular weight measured by GPC with the branching degree measured by GPC equipped with a viscometer for the polymer before the addition of the branching agent, the polymer after the addition of the branching agent, and the polymer in each step after the addition of the coupling agent.

[0286] ( Reference example A-3) Coupling conjugated diene polymer (sample A-3) The internal volume is 10 L, and the ratio of internal height (L) to diameter (D) (L / D) is 4.0. The reactor is a tank type reactor with an agitator, an inlet at the bottom and an outlet at the top, and has a jar for temperature control. Two tank-type pressure vessels with a tank cap were connected together as polymerization reactors. 1,3-butadiene, which had been previously dehydrated, was fed at 18.6 g / min, and styrene at 10.0 g / min. , and n-hexane were mixed at 175.2 g / min. The mixture was mixed in a static mixer provided in the pipe that supplied the mixture to the inlet of the reactor. n-Butyllithium was added at 0.103mmol / min to inactivate the remaining impurities. After mixing, the mixture was continuously fed to the bottom of the reactor. n-Butylpropane was used as a polymerization initiator at a rate of 0.081 mmol / min. The first reactor is vigorously mixed with a stirrer at a rate of 0.143 mmol / min. The internal temperature of the reactor was maintained at 67°C. The polymer solution was continuously withdrawn from the top of the first reactor and continuously poured into the bottom of the second reactor. The reaction was continued at 70°C, and then the mixture was fed to the static mixer from the top of the second unit. When the polymerization is sufficiently stable, 1,3-butadiene and styrene are copolymerized. From the bottom of the second reactive group, trimethoxy(4-vinylphenyl)silane ( In the table, this is abbreviated as "BS-1.") was added at a rate of 0.0190 mmol / min to form a main chain branch structure. The polymerization reaction and branching reaction were carried out to obtain a conjugated diene polymer having the above structure. Furthermore, when the polymerization reaction and the branching reaction were stabilized, the branched conjugate before the addition of the coupling agent was A small amount of the diene polymer solution was taken out and an antioxidant (BHT) was added at 0.2 g per 100 g of polymer. The solvent was then removed, and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties were measured and are shown in Table 6. Next, the polymer solution discharged from the outlet of the reactor was added with the following coupling agent (Z-1 The coupling agent shown in the table is abbreviated as "Z-1" in the table.) was used in an amount of 0.036 The mixture was mixed using a static mixer and the coupling reaction was carried out. At this time, the time until the coupling agent is added to the polymer solution flowing out from the outlet of the reactor The polymerization time was 4.8 minutes and the temperature was 68°C. The temperature during the polymerization process and the time when the coupling agent was added were The difference in temperature between the time when the coupling reaction was completed and the time when the coupling reaction was completed was 2°C. An antioxidant (BHT) was added to the polymer in an amount of 0.2 g per 100 g of polymer. After the solvent was removed, the amount of bound styrene (physical property 6) and the microstructure of the butadiene portion (1, The amount of 2-vinyl bonds (physical properties7) was measured. The results are shown in Table 6. Next, add an antioxidant (BHT) to the polymer solution after the coupling reaction for 100 g of polymer. The amount of n-hexane solution was continuously added at 0.055 g / min so that the amount was 0.2 g per unit time. The coupling reaction was completed. In contrast, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) The mixture was added continuously to a total of 25.0 g and mixed with a static mixer. The solvent was removed by stripping, and the main chain had a four-branched structure derived from the branching agent. Coupling conjugated diene polymer ( Sample A-3) was obtained. The physical properties of sample A-3 are shown in Table 6. The polymer before the addition of the branching agent, the polymer after the addition of the branching agent, and the polymer after the addition of the coupling agent are The molecular weight of the polymer in each process was measured by GPC and the molecular weight was measured by GPC with a viscometer. The structure of the coupling conjugated diene polymer was identified by comparing with the branching degree by the method described above.

[0287] [ka]

[0288] [Coupling Conjugated Diene Polymer] (Comparative Example 1-1) Coupling conjugated diene polymer (Sample 1-38) Two tank-type pressure vessels having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and an agitator-equipped tank-type reactor and a jacket for temperature control were connected together as polymerization reactors. 1,3-butadiene, which had been previously dehydrated, was mixed at 18.6 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min. In a static mixer installed in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating remaining impurities was added at 0.103 mmol / min, mixed, and then continuously supplied to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance was supplied at a rate of 0.081 mmol / min, and n-butyllithium as a polymerization initiator was supplied at a rate of 0.143 mmol / min to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the temperature inside the reactor was maintained at 67°C. The polymer solution was continuously withdrawn from the top of the first reactor and continuously fed to the bottom of the second reactor to continue the reaction at 70°C, and then fed to the static mixer from the top of the second reactor. When the polymerization was sufficiently stabilized, a small amount of the polymer solution before the addition of the coupling agent was withdrawn, and an antioxidant (BHT) was added so that the amount was 0.2 g per 100 g of polymer, after which the solvent was removed and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 7. Next, tetraethoxysilane (abbreviated as "A" in the table) was continuously added as a coupling agent to the polymer solution flowing out from the outlet of the reactor at a rate of 0.0480 mmol / min, and mixed using a static mixer to carry out a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, the temperature was 68°C, and the difference between the temperature in the polymerization process and the temperature before the coupling agent was added was 2°C. A small amount of the conjugated diene polymer solution after the coupling reaction was extracted, and an antioxidant (BHT) was added so that the amount was 0.2 g per 100 g of polymer, and then the solvent was removed, and the amount of bound styrene (physical property 6) and the microstructure of the butadiene portion (1,2-vinyl bond amount: physical property 7) were measured. The measurement results are shown in Table 7. Next, an antioxidant (BHT) was continuously added to the polymer solution after the coupling reaction at 0.055 g / min (n-hexane solution) so that the amount was 0.2 g per 100 g of polymer, and the coupling reaction was terminated. Simultaneously with the antioxidant, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) was continuously added as a rubber softener so that the amount was 25.0 g per 100 g of polymer, and mixed with a static mixer. The solvent was removed by steam stripping to obtain a coupling conjugated diene polymer (sample 1-38) having no main chain branching derived from the branching agent and having a three-branched star polymer structure derived from the coupling agent. The physical properties of sample 1-38 are shown in Table 7.

[0289] (Comparative Example 1-2) Coupling conjugated diene polymer (Sample 1-39) The coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min, but in the same manner as in Comparative Example 1-1, a coupling conjugated diene polymer (sample 1-39) was obtained that has no main chain branching derived from the branching agent and has a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 1-39 are shown in Table 7.

[0290] (Comparative Example 1-3) Coupling conjugated diene polymer (Sample 1-40) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the amount of the coupling agent was changed to 0.0190mmol / min. In the same manner as in Comparative Example 1-1, a coupling conjugated diene polymer (sample 1-40) was obtained that has no main chain branching derived from the branching agent and has an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 40 are shown in Table 7.

[0291] (Comparative Example B-1) Coupling Conjugated Diene Polymer (Sample B-1) Two tank-type pressure vessels having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and an agitator-equipped tank-type reactor and a jacket for temperature control were connected together as polymerization reactors. 1,3-butadiene, from which moisture had been removed in advance, was mixed under the conditions of 18.6 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min. In a static mixer installed in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating remaining impurities was added at 0.103 mmol / min, mixed, and then continuously supplied to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance at a rate of 0.081 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.143 mmol / min were supplied to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the temperature inside the reactor was maintained at 67°C. The polymer solution was continuously withdrawn from the top of the first reactor and continuously fed to the bottom of the second reactor where the reaction was continued at 70° C., and further fed to a static mixer from the top of the second reactor. When the polymerization reaction became stable, a small amount of the polymer solution before the addition of the coupling agent was withdrawn, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of polymer, after which the solvent was removed and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 8. Next, trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added to the polymer solution discharged from the outlet of the reactor at a rate of 0.0190 mmol / min, and at the same time, tetraethoxysilane (abbreviated as "A" in the table) was continuously added at a rate of 0.0480 mmol / min. The mixture was mixed using a static mixer to carry out a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, the temperature was 68 ° C, and the difference between the temperature in the polymerization process and the temperature before the coupling agent was added was 2 ° C. A small amount of the conjugated diene polymer solution after the coupling reaction was withdrawn, and an antioxidant (BHT) was added so that the amount was 0.2 g per 100 g of polymer, and then the solvent was removed, and the bound styrene amount (physical property 6) and the microstructure of the butadiene portion (1,2-vinyl bond amount: physical property 7) were measured. The measurement results are shown in Table 8. Next, an antioxidant (BHT) was continuously added to the polymer solution after the coupling reaction at 0.055 g / min (n-hexane solution) so that the amount was 0.2 g per 100 g of polymer, and the coupling reaction was terminated. Simultaneously with the antioxidant, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) was continuously added as a rubber softener so that the amount was 25.0 g per 100 g of polymer, and mixed with a static mixer. The solvent was removed by steam stripping to obtain a coupling conjugated diene polymer (modified conjugated diene polymer) (sample B-1). The physical properties of sample B-1 are shown in Table 8. In Table 8 (Comparative Example B-1) below, "BS-1" is listed in the branching agent column. However, in the addition method in which "BS-1" and "A" were added simultaneously as in this example, a main chain branch point could not be formed, and thus the branching agent did not function. In (Comparative Example B-1), since the "BS-1" was added after the monomer was consumed, it is assumed that after the active end was bonded to the methoxy group of the "BS-1", there was almost no monomer to polymerize with the vinyl group of the "BS-1". In other words, even if the "BS-1" was added, the "branching process" did not occur because there was no monomer. From the shrinkage factor of (Sample B-1), it can be confirmed that branches are formed only within the range of the number of functional groups of the coupling agent, and it is considered that an increase in the number of branches due to the combination of the main chain branching structure due to "BS-1" and the coupling structure in one polymer has not occurred. The structure of the coupled conjugated diene polymer was identified by comparing the molecular weight measured by GPC and the branching degree measured by GPC equipped with a viscometer for the polymer before the addition of "BS-1", the polymer after the addition of "BS-1", and the polymer in each step after the addition of "A".

[0292] (Comparative Example B-2) Coupling conjugated diene polymer (sample B-2) No branching agent was used. In addition, the coupling agent used was the coupling agent shown in (Z-1) below (abbreviated as "Z-1" in the table), and the amount added was 0.0360 mmol / min. Other conditions were the same as in Comparative Example B-1, and a coupling conjugated diene polymer (modified conjugated diene polymer) (sample B-2) was obtained that had no main chain branching derived from the branching agent and had a 10-branch star polymer structure derived from the coupling agent. The physical properties of sample B-2 are shown in Table 8.

[0293] [ka]

[0294] [Table 1]

[0295] [Table 2]

[0296] [Table 3]

[0297] [Table 4]

[0298] [Table 5]

[0299] [Table 6]

[0300] [Table 7]

[0301] [Table 8]

[0302] Example And reference examples 1-38 to 1-74, Examples And reference examples a-1 to 3, and Comparative Examples 1-4 to 1-6, and Comparative Examples b-1 to 2) Samples 1-1 to 1-40 shown in Tables 1 to 5 and 7, and samples (A-1 to 3) shown in Table 6 Using the samples (B-1 to B-2) shown in Table 8 as raw rubber, A rubber composition containing the raw rubber was obtained.

[0303] (Rubber component) Branched conjugated diene polymers and coupled conjugated diene polymers (samples 1-1 to 1-40) : 80 parts by weight (excluding rubber softener) High cis polybutadiene (Ube Industries' product name "UBEPOL BR150") :20 parts by mass

[0304] (Combination conditions) The amount of each compounding ingredient added is shown in parts by mass per 100 parts by mass of the rubber component not including the rubber softener. Silica 1 (product name "Ultrasil 7000GR" manufactured by Evonik Degussa) Nitrogen adsorption specific surface area 170m2 / g): 50.0 parts by mass Silica 2 (Rhodia product name "Zeosil Premium 200MP") Nitrogen adsorption specific surface area 220m2 / g): 25.0 parts by mass Carbon black (product name "Seast KH (N339)" manufactured by Tokai Carbon Co., Ltd.) :5.0 parts by mass Silane coupling agent (product name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass SRAE oil (product name "Process NC140" manufactured by JX Nippon Oil & Energy Corporation) :42.0 parts by mass (This includes the amount previously added as a rubber softener contained in Samples 1-1 to 1-40, A-1 to 3, and B-1 to 2.) ·Zinc white: 2.5 parts by mass Stearic acid: 1.0 parts by weight Anti-aging agent (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass ·Sulfur: 2.2 parts by mass Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide) :1.7 parts by mass Vulcanization accelerator 2 (diphenyl guanidine): 2.0 parts by mass ·Total: 239.4 parts by mass

[0305] (Mixing method) The above materials were kneaded by the following method to obtain a rubber composition. Using an internal kneader (capacity 0.3 L) equipped with a temperature control device, the raw rubber (samples 1-1 to 1-40, samples A-1 to 3, samples B-1 to 2), fillers (silica 1, silica 2, carbon black), silane coupling agent, SRAE oil, zinc oxide, and stearic acid were kneaded under the conditions of a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm in the first stage of kneading. At this time, the temperature of the internal kneader was controlled, and each rubber composition (compound) was obtained at a discharge temperature of 155 to 160°C. Next, as the second stage of kneading, the mixture obtained above was cooled to room temperature, and then the antioxidant was added and kneaded again to improve the dispersion of the silica. In this case, the discharge temperature of the mixture was adjusted to 155 to 160°C by controlling the temperature of the kneader. After cooling, in the third stage of kneading, sulfur and vulcanization accelerators 1 and 2 were added and kneaded using an open roll set at 70°C. Thereafter, the product was molded and vulcanized in a vulcanization press at 160°C for 20 minutes. The rubber compositions before and after vulcanization were evaluated. Specifically, the evaluation was performed by the following methods. The results are shown in Tables 9 to 15.

[0306] [Evaluation of characteristics] (Evaluation 1) Compound Mooney Viscosity The compound obtained above after the second mixing step and before the third mixing step was used as a sample, and the viscosity was measured using a Mooney viscometer in accordance with ISO 289 after preheating at 130°C for 1 minute and rotating the rotor at 2 revolutions per minute for 4 minutes. The results of Comparative Examples 1-4 were indexed to 100. The smaller the index, the better the processability.

[0307] (Evaluation 2) Tensile strength and tensile elongation The tensile strength and tensile elongation were measured according to the tensile test method of JIS K6251, and indexed with the results of Comparative Examples 1-4 set at 100. A larger index indicates better tensile strength and tensile elongation (breaking strength).

[0308] (Rating 3) Abrasion resistance Using an Acron abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the amount of wear was measured at a load of 44.4 N and 1000 revolutions in accordance with JIS K6264-2, and indexed with the results of Comparative Examples 1-4 set at 100. A higher index indicates better abrasion resistance.

[0309] (Evaluation 4) Viscoelastic parameters Viscoelastic parameters were measured in torsion mode using a viscoelasticity tester "ARES" manufactured by Rheometrics Scientific Co., Ltd. Each measured value was indexed with the result for the rubber composition of Comparative Example 1-4 set at 100. Tan δ measured at 0°C, a frequency of 10 Hz, and a strain of 1% was used as an index of wet skid resistance. A higher index value indicates better wet skid resistance. In addition, tan δ measured at 50°C, a frequency of 10 Hz, and a strain of 3% was used as an index of fuel economy. The smaller the index, the better the fuel economy. Furthermore, the elastic modulus (G') measured at 50°C, a frequency of 10 Hz, and a strain of 3% was used as an index of steering stability. A higher index value indicates better steering stability.

[0310] [Table 9]

[0311] [Table 10]

[0312] [Table 11]

[0313] [Table 12]

[0314] [Table 13]

[0315] [Table 14]

[0316] [Table 15]

[0317] As shown in Tables 9 to 15, compared with Comparative Examples 1-4 to 1-6, Examples 1-38 to 1-74 showed low compound Mooney viscosity when vulcanized and good processability, and were confirmed to have excellent abrasion resistance, handling stability, and rupture strength when vulcanized, as well as an excellent balance between low hysteresis loss and wet skid resistance. As shown in Table 15, it was confirmed that, compared with Comparative Examples b-1 and b-2, Examples a-1 to a-3 had low Mooney viscosity of the compound when vulcanized, exhibited good processability, and when vulcanized, had excellent abrasion resistance, handling stability, and rupture strength, and also had an excellent balance between low hysteresis loss and wet skid resistance.

[0318] Second Example Hereinafter, as a second embodiment, the present embodiment will be described in more detail by giving specific examples and comparative examples, but the present embodiment is not limited in any way by the following examples and comparative examples. Hereinafter, a conjugated diene polymer coupled with a coupling agent will be referred to as a "coupled conjugated diene polymer". Moreover, a conjugated diene polymer that is copolymerized with a nitrogen atom-containing vinyl compound and has a branched structure derived from a branching agent is referred to as a "modified branched conjugated diene polymer". Furthermore, a coupled conjugated diene polymer, a conjugated diene polymer having a branched structure, and a conjugated diene polymer not having a branched structure may be collectively referred to as a "conjugated diene polymer." Various physical properties in the examples and comparative examples were measured by the methods shown below.

[0319] (Physical Properties 1) Polymer Mooney Viscosity The Mooney viscosity of a modified branched conjugated diene polymer or a conjugated diene polymer coupled with a nitrogen atom-containing modifier (hereinafter also referred to as a "coupled conjugated diene polymer") was measured using a Mooney viscometer (manufactured by Ueshima Seisakusho Co., Ltd., product name "VR1132") in accordance with ISO 289 using an L-shaped rotor. The measurement temperature was 110° C. when the conjugated diene polymer before the coupling reaction was used as the sample, and 100° C. when the coupled conjugated diene polymer was used as the sample. First, the sample was preheated at the test temperature for 1 minute, and then the rotor was rotated at 2 rpm. The torque was measured after 4 minutes to determine the Mooney viscosity (ML (1+4) ) was decided.

[0320] (Physical property 2) Mooney relaxation rate A coupling conjugated diene polymer was used as a sample, and the Mooney viscosity was measured using a Mooney viscometer (manufactured by Ueshima Seisakusho Co., Ltd. under the trade name "VR1132") with an L-shaped rotor in accordance with ISO 289. The rotation of the rotor was then immediately stopped, and the torque was recorded in Mooney units every 0.1 seconds for 1.6 to 5 seconds after the rotor was stopped. The slope of the straight line obtained by plotting the torque versus time (seconds) on a double logarithmic scale was determined, and the absolute value of the slope was taken as the Mooney relaxation rate (MSR).

[0321] (Physical property 3) Branching degree (Bn) The branching degree (Bn) of the coupling conjugated diene polymer was measured by a GPC-light scattering method equipped with a viscosity detector as follows. A coupling conjugated diene polymer was used as a sample, and measurements were performed using a gel permeation chromatography (GPC) measuring device (manufactured by Malvern under the trade name "GPCmax VE-2001") in which three columns packed with polystyrene gel were connected together, and three detectors were connected in that order: a light scattering detector, an RI detector, and a viscosity detector (manufactured by Malvern under the trade name "TDA305"). Based on standard polystyrene, the absolute molecular weight was calculated from the results of the light scattering detector and the RI detector, and the intrinsic viscosity was calculated from the results of the RI detector and the viscosity detector. Linear polymer has an intrinsic viscosity [η] = -3.883M 0.771 The shrinkage factor (g') was calculated as the ratio of the intrinsic viscosity corresponding to each molecular weight, where M represents the absolute molecular weight. The obtained shrinkage factor (g') was then used to calculate the branching degree (Bn), defined as g' = 6Bn / [(Bn+1)(Bn+2)]. The eluent used was tetrahydrofuran (hereinafter also referred to as "THF") containing 5 mmol / L triethylamine. The columns used were "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL" manufactured by Tosoh Corporation. 20 mg of the measurement sample was dissolved in 10 mL of THF to prepare a measurement solution, and 100 μL of the measurement solution was injected into a GPC measurement device and measured under conditions of an oven temperature of 40° C. and a THF flow rate of 1 mL / min.

[0322] (Physical property 4) Molecular weight <Measurement condition 1>: The modified branched conjugated diene polymer or the coupled conjugated diene polymer was used as a sample, and a chromatogram was measured using a GPC measuring device (manufactured by Tosoh Corporation under the trade name "HLC-8320GPC") in which three columns packed with polystyrene gel were connected together, and an RI detector (manufactured by Tosoh Corporation under the trade name "HLC8020") was used. Based on a calibration curve obtained using standard polystyrene, the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were determined. The eluent used was tetrahydrofuran (THF) containing 5 mmol / L triethylamine. Three columns, Tosoh Corporation's "TSKgel SuperMultiporeHZ-H" (trade name), were connected, and a Tosoh Corporation's "TSKguardcolumn SuperMP(HZ)-H" (trade name) was connected in front of them as a guard column. 10 mg of the measurement sample was dissolved in 10 mL of THF to prepare a measurement solution, and 10 μL of the measurement solution was injected into a GPC measurement device and measured under conditions of an oven temperature of 40° C. and a THF flow rate of 0.35 mL / min. Among the various samples measured under the above measurement condition 1, samples whose molecular weight distribution (Mw / Mn) was less than 1.6 were measured again under the following measurement condition 2. For samples whose molecular weight distribution was 1.6 or more when measured under measurement condition 1, the measured value under measurement condition 1 was used. <Measurement condition 2>: The modified branched conjugated diene polymer or the coupled conjugated diene polymer was used as a sample, and a chromatogram was measured using a GPC measuring device having three columns connected together, each column using a polystyrene gel as a packing material. The weight average molecular weight (Mw) and number average molecular weight (Mn) were determined based on a calibration curve using standard polystyrene. The eluent used was THF containing 5 mmol / L triethylamine. The columns used were the following: guard column: Tosoh Corporation's product name "TSKguardcolumn SuperH-H"; columns: Tosoh Corporation's product names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000". An RI detector (manufactured by Tosoh Corporation under the trade name "HLC8020") was used under the conditions of an oven temperature of 40° C. and a THF flow rate of 0.6 mL / min. 10 mg of a sample to be measured was dissolved in 20 mL of THF to prepare a measurement solution, and 20 μL of the measurement solution was injected into a GPC measurement device for measurement. For samples that were measured under measurement condition 1 and had a molecular weight distribution value of less than 1.6, measurement was performed under measurement condition 2, and the measured value was adopted.

[0323] (Physical property 5) Modification rate The modification rates of the modified branched conjugated diene polymer and the coupled conjugated diene polymer were measured by a column adsorption GPC method as follows. The modified branched conjugated diene polymer and the coupled conjugated diene polymer were used as samples, and the measurements were carried out by utilizing the adsorption property of the modified basic polymer component in a GPC column packed with silica gel. In addition, when a nitrogen atom-containing vinyl compound is used as a monomer in the polymerization step, a conjugated diene polymer that has already been modified in the polymerization step is obtained, so the modification rate was also measured for the "modified branched conjugated diene polymer" prior to the coupling step. The amount of a sample solution containing a sample and low molecular weight internal standard polystyrene was adsorbed onto the silica-based column by measuring the difference between the chromatogram measured using a polystyrene-based column and the chromatogram measured using a silica-based column, and the modification rate was calculated. Specifically, it is as follows: Furthermore, samples that were measured under the above (Physical Property 4) Measurement Condition 1 and had a molecular weight distribution value of 1.6 or more were measured under the following Measurement Condition 3. Samples that were measured under the above (Physical Property 4) Measurement Condition 1 and had a molecular weight distribution value of less than 1.6 were measured under the following Measurement Condition 4.

[0324] <Preparation of sample solution>: 10 mg of the sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution. <Measurement condition 3>: GPC measurement conditions using polystyrene columns: A Tosoh Corporation product name "HLC-8320GPC" was used, and 10 μL of the sample solution was injected into the device using THF containing 5 mmol / L triethylamine as the eluent. A chromatogram was obtained using an RI detector under the following conditions: column oven temperature 40°C, THF flow rate 0.35 mL / min. The columns used were three Tosoh Corporation products (TSKgel SuperMultiporeHZ-H) connected together, with a Tosoh Corporation product (TSKguardcolumn SuperMP(HZ)-H) connected in front of them as a guard column.

[0325] <Measurement condition 4>: THF containing 5 mmol / L triethylamine was used as the eluent, and 20 μL of the sample solution was injected into the device for measurement. The columns used were a guard column manufactured by Tosoh Corporation under the trade name "TSKguardcolumn SuperH-H" and columns manufactured by Tosoh Corporation under the trade names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000". Measurement was performed using an RI detector (manufactured by Tosoh Corporation, HLC8020) under conditions of a column oven temperature of 40°C and a THF flow rate of 0.6 mL / min, to obtain a chromatogram.

[0326] GPC measurement conditions using a silica column: A Tosoh Corporation product name "HLC-8320GPC" was used, THF was used as the eluent, 50 μL of the sample solution was injected into the device, and a chromatogram was obtained using an RI detector under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 ml / min. The columns used were Zorbax PSM-1000S, PSM-300S, and PSM-60S, and a guard column "DIOL 4.6 × 12.5 mm 5 micron" was connected to the front of the columns.

[0327] How to calculate the denaturation rate: The total peak area of ​​the chromatogram using the polystyrene column was set as 100, the peak area of ​​the sample was set as P1, the peak area of ​​the standard polystyrene was set as P2, the total peak area of ​​the chromatogram using the silica column was set as 100, the peak area of ​​the sample was set as P3, and the peak area of ​​the standard polystyrene was set as P4, and the modification rate (%) was calculated using the following formula. Denaturation rate (%) = [1-(P2 x P3) / (P1 x P4)] x 100 (where P1+P2=P3+P4=100)

[0328] (Physical property 6) Bound styrene content A coupling conjugated diene polymer not containing a rubber softener was used as a sample, and 100 mg of the sample was dissolved in chloroform up to 100 mL to prepare a measurement sample. The amount of bound styrene (mass%) relative to 100 mass% of the sample coupled conjugated diene polymer was measured based on the amount of absorption of ultraviolet light (around 254 nm) by the phenyl group of styrene (measuring device: Shimadzu Corporation spectrophotometer "UV-2450").

[0329] (Physical property 7) Microstructure of butadiene part (1,2-vinyl bond amount) A coupling conjugated diene polymer not containing a rubber softener was used as a sample, and 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare a measurement sample. Using a solution cell, infrared spectra are recorded from 600 to 1000 cm -1 The measurement was performed in the range of 100 sq. m., and the microstructure of the butadiene portion, i.e., the 1,2-vinyl bond amount (referred to as the vinyl bond amount (1,2-bond amount) in the table) (mol %) was determined from the absorbance at a predetermined wave number according to the calculation formula of the Hampton method (the method described in R.R. Hampton, Analytical Chemistry 21, 923 (1949)) (measuring device: Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

[0330] (Physical Property 8) Molecular weight (absolute molecular weight) measured by GPC-light scattering method The coupling conjugated diene polymer was used as a sample, and a chromatogram was measured using a GPC-light scattering measuring device in which three columns packed with polystyrene gel were connected, and the weight average molecular weight (Mw-i) was calculated based on the solution viscosity and the light scattering method (also referred to as "absolute molecular weight"). The eluent used was a mixed solution of tetrahydrofuran and triethylamine (THF in TEA: prepared by mixing 5 mL of triethylamine in 1 L of tetrahydrofuran). The columns used were a guard column (manufactured by Tosoh Corporation under the trade name "TSKguardcolumn HHR-H") and columns (manufactured by Tosoh Corporation under the trade names "TSKgel G6000HHR", "TSKgel G5000HHR", and "TSKgel G4000HHR"). A GPC-light scattering measuring device (trade name "Viscotek TDAmax" manufactured by Malvern Instruments) was used under conditions of an oven temperature of 40° C. and a THF flow rate of 1.0 mL / min. 10 mg of the measurement sample was dissolved in 20 mL of THF to prepare a measurement solution, and 200 μL of the measurement solution was injected into the GPC measurement device for measurement.

[0331] [Conjugated diene polymer] ( Reference example 2-1) Coupling conjugated diene polymer (sample 2-1) The internal volume is 10 L, and the ratio of internal height (L) to diameter (D) (L / D) is 4.0. The reactor is a tank type reactor with an agitator, an inlet at the bottom and an outlet at the top, and has a jar for temperature control. Two tank-type pressure vessels with a tank cap were connected together as polymerization reactors. 1,3-butadiene, which had been previously dehydrated, was fed at 18.6 g / min, and styrene at 10.0 g / min. The mixture was fed to the inlet of the reactor. In the static mixer installed in the piping that supplies the gas, a gas for inactivating remaining impurities is used. -Butyllithium was added at 0.103mmol / min and mixed, then continuously poured into the bottom of the reactor. In addition, 2,2-bis(2-oxolanyl)propane was added as a polar substance at 0.0 At a rate of 81 mmol / min, 0.143 mmol of n-butyllithium was used as a polymerization initiator. The mixture was fed to the bottom of the first reactor, which was vigorously mixed with an agitator, at a rate of 1 / min. The temperature inside the reactor was kept at 67°C. The temperature was kept at .degree. The polymer solution was continuously withdrawn from the top of the first reactor and continuously poured into the bottom of the second reactor. The reaction was continued at 70°C, and then the mixture was fed to the static mixer from the top of the second unit. When the polymerization is sufficiently stable, 1,3-butadiene and styrene are copolymerized. From the bottom of the second reactive group, 1-(4-N,N-dimethyl) (N-1)-1-phenylethylene (abbreviated as "N-1" in the table) at 0.120 The branching agent trimethoxy(4-vinylphenyl) )silane (abbreviated as "BS-1" in the table) was added at a rate of 0.0190 mmol / min. Then, a polymerization reaction and a branching reaction were carried out to obtain a conjugated diene polymer having a main chain branched structure. After the polymerization reaction and the branching reaction were stabilized, the conjugated diene before the addition of the coupling agent was A small amount of the polymer (modified branched conjugated diene polymer) solution was extracted and an antioxidant (BHT) was added. After adding 0.2 g per 100 g of polymer, the solvent was removed and the mixture was stirred at 110°C. The knee viscosity and various molecular weights were measured, and the physical properties are shown in Table 16. Next, the polymer solution discharged from the outlet of the reactor was mixed with tetraethoxysilane as a coupling agent. Silane (abbreviated as "A" in the table) was added continuously at a rate of 0.0480 mmol / min. The mixture was mixed using a static mixer and subjected to a coupling reaction. The time it took for the coupling agent to be added to the polymer solution flowing out of the nozzle was 4.8 minutes, and the temperature was The difference between the temperature during the polymerization process and the temperature before adding the coupling agent is 68°C. After the coupling reaction, a small amount of the conjugated diene polymer solution was taken out and added with an antioxidant. (BHT) was added in an amount of 0.2 g per 100 g of polymer, and the solvent was then removed to give a The amount of styrene in the mixture (Physical Properties 6) and the microstructure of the butadiene part (1,2-vinyl bond amount: Physical Properties The results are shown in Table 16. Next, add an antioxidant (BHT) to the polymer solution after the coupling reaction for 100 g of polymer. The amount of n-hexane solution was continuously added at 0.055 g / min so that the amount was 0.2 g per unit time. The coupling reaction was completed. In contrast, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) The mixture was added continuously to a total of 25.0 g and mixed with a static mixer. The solvent was removed by stripping, and a part of the main chain was found to contain the compound represented by the following formula (2-1). having a four-branched structure derived from a certain branching agent (hereinafter also referred to as “branching agent structure (2-1)”); Coupling conjugated diene polymer with a three-branched star-shaped polymer structure derived from a coupling agent (Sample 2-1) was obtained. The physical properties of Sample 2-1 are shown in Table 16. The polymer before the addition of the branching agent, the polymer after the addition of the branching agent, and the polymer after the addition of the coupling agent are The molecular weight of the polymer in each process was measured by GPC and the molecular weight was measured by GPC with a viscometer. The structure of the coupling conjugated diene polymer was identified by comparing with the branching degree by the method described below. The structure of each sample was identified in the same manner.

[0332] [ka]

[0333] In formula (2-1), Q 1 represents any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. X 1 is a single bond or an organic group containing any one selected from the group consisting of carbon, hydrogen, nitrogen, sulfur, and oxygen. Y 1 represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. Y 1are independent and may be the same or different.

[0334] ( Reference example 2-2) Coupling conjugated diene polymer (sample 2-2) The coupling agent was converted from tetraethoxysilane to 1,2-bis(triethoxysilyl)ethene. (abbreviated as "B" in the table) and the amount added was changed to 0.0360 mmol / min. Outside, Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-2) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-2 are shown in Table 16.

[0335] (Example 2-3) Coupling conjugated diene polymer (sample 2-3) Except for changing the coupling agent from tetraethoxysilane to 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (abbreviated as "C" in the table) and changing its addition amount to 0.0360mmol / min, the same procedure as in Example 2-1 was used to obtain a coupling conjugated diene polymer (sample 2-3) having a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-3 are shown in Table 16.

[0336] (Example 2-4) Coupling conjugated diene polymer (sample 2-4) Except for changing coupling agent from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in table), and changing its addition amount to 0.0360mmol / min, in the same manner as in Example 2-1, obtain a coupling conjugated diene polymer (sample 2-4) that has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-4 are shown in Table 16.

[0337] (Example 2-5) Coupling conjugated diene polymer (sample 2-5) Except for changing the coupling agent from tetraethoxysilane to tris(3-trimethoxysilylpropyl)amine (abbreviated as "E" in the table) and changing its addition amount to 0.0250mmol / min, the same procedure as in Example 2-1 was used to obtain a coupling conjugated diene polymer (sample 2-5) having a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and a 6-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-5 are shown in Table 16.

[0338] (Example 2-6) Coupling conjugated diene polymer (sample 2-6) Except for changing the coupling agent from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) and changing its addition amount to 0.0190mmol / min, the same procedure as in Example 2-1 was used to obtain a coupling conjugated diene polymer (sample 2-6) having a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-6 are shown in Table 16.

[0339] (Example 2-7) Coupling conjugated diene polymer (sample 2-7) Except for changing the coupling agent from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) and changing its addition amount to 0.0160mmol / min, the same procedure as in Example 2-1 was used to obtain a coupling conjugated diene polymer (sample 2-7) having a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-7 are shown in Table 16.

[0340] (Example 2-8) Coupling conjugated diene polymer (sample 2-8) The addition rate of 1,3-butadiene was changed from 18.6g / min to 24.3g / min, the addition rate of styrene was changed from 10.0g / min to 4.3g / min, and the addition rate of 2,2-bis(2-oxolanyl)propane as a polar substance was changed from 0.081mmol / min to 0.044mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the addition amount was changed to 0.0160mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-8) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-8 are shown in Table 16.

[0341] (Example 2-9) Coupling conjugated diene polymer (sample 2-9) The addition rate of 1,3-butadiene was changed from 18.6g / min to 17.1g / min, the addition rate of styrene was changed from 10.0g / min to 11.5g / min, and the addition rate of 2,2-bis(2-oxolanyl)propane as a polar substance was changed from 0.081mmol / min to 0.089mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the addition amount was changed to 0.0160mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-9) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-9 are shown in Table 17.

[0342] (Example 2-10) Coupling conjugated diene polymer (sample 2-10) The addition rate of polar substance 2,2-bis(2-oxolanyl)propane was changed from 0.081mmol / min to 0.200mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and its addition amount was changed to 0.0160mmol / min, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-10) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-10 are shown in Table 17.

[0343] ( Reference example 2-11) Coupling conjugated diene polymer (sample 2-11) The branching agent was converted from trimethoxy(4-vinylphenyl)silane to dimethylmethoxy(4-vinyl (BS-2) in the table, and the amount added was 0.0350m mol / min, and the coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilane) (xysilyl)ethane (abbreviated as "B" in the table), and the amount added was 0.0360mmol Except for changing to l / min. Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-11) was obtained, which has a two-branch structure derived from the branching agent structure (2-1) in a part of the main chain and a four-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-11 are shown in Table 17.

[0344] (Example 2-12) Coupling conjugated diene polymer (sample 2-12) The branching agent was changed from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), and its addition amount was changed to 0.0350mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-12) having a two-branch structure derived from the branching agent structure (2-1) in a part of the main chain and a four-branch star polymer structure derived from the coupling agent was obtained. The physical properties of sample 2-12 are shown in Table 17.

[0345] (Example 2-13) Coupling conjugated diene polymer (sample 2-13) The branching agent was changed from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), and its addition amount was changed to 0.0350mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and its addition amount was changed to 0.0160mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-13) was obtained, which has a two-branch structure derived from the branching agent structure (2-1) in a part of the main chain and an eight-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-13 are shown in Table 17.

[0346] ( Reference example 2-14) Coupling conjugated diene polymer (sample 2-14) Branching agents were prepared from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-(dimethylphenyl)silane) (phenylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table) and its addition The amount was changed to 0.0120 mmol / min, and the coupling agent was changed from tetraethoxysilane to 1, The amount of 2-bis(triethoxysilyl)ethane (abbreviated as "B" in the table) was changed to Except for changing to 0.0360mmol / min, Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-14) was obtained, which has a three-branched structure derived from the branching agent (hereinafter also referred to as "branching agent structure (2-2)"), which is a compound represented by the following formula (2-2), in a part of the main chain, and has a four-branched star polymer structure derived from the coupling agent. The physical properties of sample 2-14 are shown in Table 17.

[0347] [ka]

[0348] In formula (2-2), X 2 , X 3 is a single bond or an organic group containing any one selected from the group consisting of carbon, hydrogen, nitrogen, sulfur, and oxygen. Y 2 , Y 3 represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. Y 2 , Y 3 are independent and may be the same or different.

[0349] (Example 2-15) Coupling conjugated diene polymer (sample 2-15) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table), and the amount added was changed to 0.0120mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and the amount added was changed to 0.0360mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-15) having a three-branched structure derived from the branching agent structure (2-2) in a part of the main chain and a four-branched star polymer structure derived from the coupling agent was obtained. The physical properties of sample 2-15 are shown in Table 17.

[0350] (Example 2-16) Coupling conjugated diene polymer (sample 2-16) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table), and the amount added was changed to 0.0120mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0160mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-16) having a three-branched structure derived from the branching agent structure (2-2) in a part of the main chain and an eight-branched star polymer structure derived from the coupling agent was obtained. The physical properties of sample 2-16 are shown in Table 17.

[0351] ( Reference example 2-17) Coupling conjugated diene polymer (sample 2-17) Branching agents were synthesized from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-trimethoxy (xysilylphenyl)ethylene (abbreviated as "BS-4" in the table), and the amount added was 0. The coupling agent was changed from tetraethoxysilane to 1,2-bis(1,2-diphenylsilane). (triethoxysilyl)ethane (abbreviated as "B" in the table), and the amount added was 0.03 Except for changing to 60mmol / min, Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-17) was obtained, which has a 7-branch structure derived from the branching agent structure (2-2) in a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-17 are shown in Table 18.

[0352] (Example 2-18) Coupling conjugated diene polymer (sample 2-18) The branching agent was changed from trimethoxy(4-vinylphenyl)silane to 1,1-bis(4-trimethoxysilylphenyl)ethylene (abbreviated as "BS-4" in the table), and its addition amount was changed to 0.0210mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-18) was obtained, which has a 7-branch structure derived from the branching agent structure (2-2) in part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-18 are shown in Table 18.

[0353] (Example 2-19) Coupling conjugated diene polymer (Sample 2-19) The branching agent was changed from trimethoxy (4-vinylphenyl) silane to 1,1-bis (4-trimethoxysilylphenyl) ethylene (abbreviated as "BS-4" in the table), and its addition amount was changed to 0.0210mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and its addition amount was changed to 0.0160mmol / min, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-19) was obtained, which has a 7-branch structure derived from the branching agent structure (2-2) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-19 are shown in Table 18.

[0354] ( Reference example 2-20) Coupling conjugated diene polymer (sample 2-20) The branching agent was converted from trimethoxy(4-vinylphenyl)silane to trichloro(4-vinylphenyl)silane. (BS-5) in the table, and the amount added was 0.0190 mmol. / min, and the coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilane) (aryl)ethane (abbreviated as "B" in the table), and the amount added was 0.0360 mmol / min. Other than changing it to Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-20) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-20 are shown in Table 18.

[0355] (Example 2-21) Coupling conjugated diene polymer (sample 2-21) The branching agent was changed from trimethoxy (4-vinylphenyl) silane to trichloro (4-vinylphenyl) silane (abbreviated as "BS-5" in the table), and its addition amount was changed to 0.0190mmol / min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table), and its addition amount was changed to 0.0360mmol / min, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-21) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-21 are shown in Table 18.

[0356] (Example 2-22) Coupling conjugated diene polymer (sample 2-22) The branching agent was changed from trimethoxy (4-vinylphenyl) silane to trichloro (4-vinylphenyl) silane (abbreviated as "BS-5" in the table), and its addition amount was changed to 0.0190mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and its addition amount was changed to 0.0160mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-22) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-22 are shown in Table 18.

[0357] (Example 2-23) Coupling conjugated diene polymer (sample 2-23) The amount of branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) added was changed from 0.0190mmol / min to 0.0100mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190mmol / min, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-23) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-23 are shown in Table 18.

[0358] (Example 2-24) Coupling conjugated diene polymer (Sample 2-24) The amount of branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) added was changed from 0.0190mmol / min to 0.0250mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190mmol / min, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-24) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-24 are shown in Table 19.

[0359] (Example 2-25) Coupling conjugated diene polymer (sample 2-25) The amount of branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) added was changed from 0.0190mmol / min to 0.0350mmol / min, the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-25) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-25 are shown in Table 19.

[0360] (Example 2-26) Coupling conjugated diene polymer (sample 2-26) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount was changed to 0.0190mmol / min, and the SRAE oil added as a rubber softener was replaced with liquid rubber (Kuraray Co., Ltd. liquid polybutadiene LBR-302). In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-26) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-26 are shown in Table 19.

[0361] (Example 2-27) Coupling conjugated diene polymer (sample 2-27) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount was changed to 0.0190mmol / min, and the SRAE oil added as a rubber softener was replaced with resin (Yasuhara Chemical Co., Ltd., terpene resin YS resin PX1250). In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-27) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-27 are shown in Table 19.

[0362] (Example 2-28) Coupling conjugated diene polymer (sample 2-28) Coupling agent is changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in table), its amount is changed to 0.0190mmol / min, and naphthenic oil (Nynas naphthenic oil Nytex810) is added instead of SRAE oil added as rubber softener, in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-28) is obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-28 are shown in Table 19.

[0363] (Example 2-29) Coupling conjugated diene polymer (Sample 2-29) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount was changed to 0.0190mmol / min, and no rubber softener was added. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-29) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-29 are shown in Table 19.

[0364] (Example 2-30) Coupling conjugated diene polymer (sample 2-30) Coupling agent is changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), its amount is changed to 0.0190mmol / min, and the amount of SRAE oil added as rubber softener is changed from 25.0g to 37.5g per 100g of polymer, but in the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-30) having a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent is obtained. The physical properties of sample 2-30 are shown in Table 19.

[0365] ( Reference example 2-31) Conjugated diene polymer (sample 2-31) When the polymerization is sufficiently stable, trimethoprim is added as a branching agent to the bottom of the second reactive group. 0.0190mmol bis(4-vinylphenyl)silane (abbreviated as "BS-1" in the table). 1 / min, except that no coupling agent was added. Reference example In the same manner as in 2-1, a conjugated diene polymer (sample 2-31) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and does not show the star-shaped coupling structure derived from the coupling agent. The physical properties of sample 2-31 are shown in Table 20. For the sake of convenience, the various physical properties of the conjugated diene polymer of Sample 2-31 are listed in Table 20 under "Cup The results are listed in the "Ring-conjugated diene polymer" column.

[0366] ( Reference example 2-32) Coupling conjugated diene polymer (sample 2-32) When the polymerization is sufficiently stable, trimethoprim is added as a branching agent to the bottom of the second reactive group. 0.0190mmol bis(4-vinylphenyl)silane (abbreviated as "BS-1" in the table). The coupling agent was tetraethoxysilane (represented as "A" in the table) at a rate of 1 / min. The amount of added 100 mmol / min was changed from 0.0480 mmol / min to 0.0120 mmol / min. Outside, Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-32) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and a 3-branch star polymer structure derived from the coupling agent in part. The physical properties of sample 2-32 are shown in Table 20.

[0367] (Example 2-33) Coupling conjugated diene polymer (Sample 2-33) When the polymerization was sufficiently stable, trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) was added as a branching agent from the bottom of the second reactive group at a rate of 0.0190mmol / min, and tetraethoxysilane was replaced with tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) as a coupling agent, and the amount of addition was changed to 0.0038mmol / min. In the same manner as in Example 2-1, a coupling conjugated diene polymer (sample 2-33) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and a 8-branch star polymer structure derived from the coupling agent in part. The physical properties of sample 2-33 are shown in Table 20.

[0368] ( Reference example 2-34) Coupling conjugated diene polymer (sample 2-34) When the polymerization is sufficiently stable, dimethyl ether is added as a branching agent to the bottom of the second reactive group. Methoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table) at 0.0350 The coupling agent tetraethoxysilane was added at a rate of 0.0 mmol / min. Except for changing from 480mmol / min to 0.0120mmol / min, Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-34) was obtained, which has a bi-branched structure derived from the branching agent structure (2-1) in part of the main chain and a tri-branched star polymer structure derived from the coupling agent in part. The physical properties of sample 2-34 are shown in Table 20.

[0369] ( Reference example 2-35) Coupling conjugated diene polymer (sample 2-35) When the polymerization is sufficiently stable, the 1,1- Bis(4-(dimethylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table) ) was added at a rate of 0.0120 mmol / min, and the coupling agent tetraethoxysilane Except for changing the amount of added water from 0.0480mmol / min to 0.0120mmol / min, Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-35) was obtained, which has a tri-branched structure derived from the branching agent structure (2-2) in part of the main chain and a tri-branched star polymer structure derived from the coupling agent in part. The physical properties of sample 2-35 are shown in Table 20.

[0370] (Example 2-36) Coupling conjugated diene polymer (Sample 2-36) Except for changing the coupling agent from tetraethoxysilane to 3-(benzylideneamino)propyltriethoxysilane (abbreviated as "G" in the table) and changing its addition amount to 0.0620mmol / min, in the same manner as in Example 2-1, obtain a coupling conjugated diene polymer (sample 2-36) having a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and a 2-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-36 are shown in Table 20.

[0371] ( Reference example 2-37) Coupling conjugated diene polymer (sample 2-37) 1,3-butadiene added to the first reactor from 18.6g / min to 13.95g / min The branching agent and 1,3-butadiene were added at 4.65g from the bottom of the second reaction unit. g / min. Reference example In the same manner as in 2-1, a coupling conjugated diene polymer (sample 2-37) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-37 are shown in Table 20.

[0372] (Example 2-38) Coupling conjugated diene polymer (Sample 2-38) Nitrogen-containing vinyl compound was changed from 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene to N,N-dimethylvinylbenzylamine (abbreviated as "N-2" in the table), and added at a rate of 0.120mmol / min, and coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and its addition rate was changed to 0.0160mmol / min. Except for this, a coupling conjugated diene polymer (sample 2-38) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-38 are shown in Table 20.

[0373] (Example 2-39) Coupling conjugated diene polymer (Sample 2-39) Nitrogen-containing vinyl compound was changed from 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene to 4-(2-pyrrolidinoethyl)styrene (abbreviated as "N-3" in the table), and added at a rate of 0.120mmol / min, and coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and its addition rate was changed to 0.0160mmol / min. Except for this, a coupling conjugated diene polymer (sample 2-39) was obtained, which has a 4-branch structure derived from the branching agent structure (2-1) in part of the main chain and an 8-branch star polymer structure derived from the coupling agent, in the same manner as in Example 2-1. The physical properties of sample 2-39 are shown in Table 20.

[0374] (Example 2-40) Coupling conjugated diene polymer (Sample 2-40) An autoclave with an internal volume of 5 L (L / D: 3.4), equipped with a stirrer and a jacket and capable of controlling temperature was used as a reactor. 1995 g of normal hexane and n-butyllithium for neutralizing impurities present in the reactor that may hinder the polymerization reaction were placed in the reactor, and the mixture was stirred at 70°C for 5 minutes. The mixture was then cooled to room temperature, the solution was removed, and the reactor was emptied. Next, 1,670 g of normal hexane from which impurities had been removed, 83 g of styrene, 236 g of 1,3-butadiene, and 2.73 mmol of 2,2-bis(2-oxolanyl)propane as a polar substance were placed in a reactor, and when the temperature inside the reactor was 56°C, 2.92 mmol of n-butyllithium (referred to as "NBL" in the table) was added as a polymerization initiator to initiate polymerization. Immediately after the polymerization started, the temperature in the reactor rose and reached a peak temperature of 79°C. When a drop in temperature was confirmed, 0.90 mmol of trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) as a branching agent and 0.150 mmol of 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene (abbreviated as "N-1" in the table) as a nitrogen atom-containing vinyl compound were added together, stirred for 5 minutes, and 0.83 mmol of tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) as a coupling agent was added, and stirred for another 5 minutes. The stirring speed at this time was 200 rpm. The coupling agent was added 7 minutes after the peak temperature was reached. The reaction was terminated by adding 2.92 mmol of ethanol as a polymerization terminator, to obtain a polymer solution containing a coupled conjugated diene polymer. To the resulting polymerization solution, 0.64 g of 2,6-di-tert-butyl-4-hydroxytoluene was added as an antioxidant, and the solvent was then removed by steam stripping. After vacuum drying, a coupled conjugated diene polymer 2-40 was obtained. The physical properties are shown in Table 22 below.

[0375] (Comparative Example 2-1) Coupling conjugated diene polymer (Sample 2-41) Two tank-type pressure vessels having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and an agitator as a tank-type reactor and a jacket for temperature control were connected together as polymerization reactors. 1,3-butadiene, which had been previously dehydrated, was mixed at 18.6 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min. In a static mixer installed in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating remaining impurities was added at 0.103 mmol / min, mixed, and then continuously supplied to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance was supplied at a rate of 0.081 mmol / min, and n-butyllithium as a polymerization initiator was supplied at a rate of 0.143 mmol / min to the bottom of the first reactor, which was vigorously mixed with a stirrer, and the temperature inside the reactor was maintained at 67°C. The polymer solution was continuously withdrawn from the top of the first reactor and continuously fed to the bottom of the second reactor to continue the reaction at 70°C, and then fed to the static mixer from the top of the second reactor. When the polymerization was sufficiently stable, a small amount of the polymer solution before the addition of the coupling agent was withdrawn, and an antioxidant (BHT) was added so that the amount was 0.2 g per 100 g of polymer, after which the solvent was removed, and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 21. Next, tetraethoxysilane (abbreviated as "A" in the table) was continuously added as a coupling agent to the polymer solution flowing out from the outlet of the reactor at a rate of 0.0480 mmol / min, and mixed using a static mixer to carry out a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, the temperature was 68°C, and the difference between the temperature in the polymerization process and the temperature before the coupling agent was added was 2°C. A small amount of the conjugated diene polymer solution after the coupling reaction was extracted, and an antioxidant (BHT) was added so that the amount was 0.2 g per 100 g of polymer, and then the solvent was removed, and the bound styrene amount (physical property 6) and the microstructure of the butadiene portion (1,2-vinyl bond amount: physical property 7) were measured. The measurement results are shown in Table 21. Next, an antioxidant (BHT) was continuously added to the polymer solution after the coupling reaction at 0.055 g / min (n-hexane solution) so that the amount was 0.2 g per 100 g of polymer, and the coupling reaction was terminated. Simultaneously with the antioxidant, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) was continuously added as a rubber softener so that the amount was 25.0 g per 100 g of polymer, and mixed with a static mixer. The solvent was removed by steam stripping to obtain a coupling conjugated diene polymer (sample 2-41) having no main chain branching derived from the branching agent and having a three-branched star polymer structure derived from the coupling agent. The physical properties of sample 2-41 are shown in Table 21.

[0376] (Comparative Example 2-2) Coupling conjugated diene polymer (Sample 2-42) A coupling conjugated diene polymer (sample 2-42) having no main chain branching derived from the branching agent and having a four-branched star polymer structure derived from the coupling agent was obtained in the same manner as in Comparative Example 2-1, except that the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table) and the amount of the coupling agent added was changed to 0.0360 mmol / min. The physical properties of sample 2-42 are shown in Table 21.

[0377] (Comparative Example 2-3) Coupling conjugated diene polymer (Sample 2-43) The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and its addition amount was changed to 0.0190mmol / min, but in the same manner as in Comparative Example 2-1, a coupling conjugated diene polymer (sample 2-43) was obtained that has no main chain branching derived from the branching agent and has an 8-branch star polymer structure derived from the coupling agent. The physical properties of sample 2-43 are shown in Table 21.

[0378] (Comparative Example 2-4) Coupling conjugated diene polymer (Sample 2-44) A 5 L internal volume autoclave equipped with a stirrer and a jacket and capable of controlling temperature was used as a reactor. 1670 g of normal hexane, 83 g of styrene, 236 g of 1,3-butadiene, and 1.91 mmol of 2,2-bis(2-oxolanyl)propane as a polar substance, from which impurities had been removed in advance, were placed in the reactor, and when the temperature inside the reactor was 58°C, 2.55 mmol of a polymerization initiator, n-butyllithium, was added to initiate polymerization. Immediately after the start of polymerization, the temperature in the reactor rose, and when the temperature reached its peak and a drop in temperature was confirmed, 0.83 mmol of tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) was added as a coupling agent and stirred for another 10 minutes. 2.55 mmol of ethanol was added as a polymerization terminator to terminate the reaction, and a polymer solution containing a modified conjugated diene polymer was obtained. 0.64 g of 2,6-di-tert-butyl-4-hydroxytoluene was added as a stabilizer to the obtained polymerization solution, and the solvent was removed by steam stripping, and the mixture was dried in vacuum to obtain a modified conjugated diene polymer (sample 2-44). The physical properties are shown in Table 22 below.

[0379] [Table 16]

[0380] [Table 17]

[0381] [Table 18]

[0382] [Table 19]

[0383] [Table 20]

[0384] [Table 21]

[0385] [Table 22]

[0386] Example And reference examples 2-41 to 2-80, and Comparative Examples 5 to 8) Samples 2-1 to 2-44 shown in Tables 16 to 22 were used as raw rubber and the following formulation was used. Then, rubber compositions containing the respective raw rubber materials were obtained.

[0387] (Rubber component) Conjugated diene polymers and coupled conjugated diene polymers (samples 2-1 to 2-44) : 80 parts by mass (parts by mass of polymer not including rubber softener) High cis polybutadiene (product name "UBEPOL BR150" manufactured by Ube Industries) :20 parts by mass

[0388] (Combination conditions) The amount of each compounding ingredient added is shown in parts by mass per 100 parts by mass of the rubber component not including the rubber softener. Silica 1 (product name "Ultrasil 7000GR" manufactured by Evonik Degussa) Nitrogen adsorption specific surface area 170m2 / g): 50.0 parts by mass Silica 2 (Rhodia product name "Zeosil Premium 200MP") Nitrogen adsorption specific surface area 220m2 / g): 25.0 parts by mass Carbon black (product name "Seast KH (N339)" manufactured by Tokai Carbon Co., Ltd.) :5.0 parts by mass Silane coupling agent (product name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass SRAE oil (product name "Process NC140" manufactured by JX Nippon Oil & Energy Corporation) :42.0 parts by mass (Including the amount previously added as a rubber softener in samples 2-1 to 2-44) ·Zinc white: 2.5 parts by mass Stearic acid: 1.0 parts by weight Anti-aging agent (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass ·Sulfur: 2.2 parts by mass Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide) :1.7 parts by mass Vulcanization accelerator 2 (diphenyl guanidine): 2.0 parts by mass ·Total: 239.4 parts by mass

[0389] (Mixing method) The above materials were kneaded in the following manner to obtain a rubber composition. In the first stage of mixing, raw rubber (samples 2-1 to 2-44), fillers (silica 1, silica 2, carbon black), silane coupling agent, SRAE oil, zinc oxide, and stearic acid were mixed at a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm using an internal mixer (capacity 0.3 L) equipped with a temperature control device. At this time, the temperature of the internal mixer was controlled, and each rubber composition (compound) was obtained at a discharge temperature of 155 to 160°C. Next, in the second stage of kneading, the mixture obtained above was cooled to room temperature, and then the antioxidant was added and kneaded again to improve the dispersion of the silica. In this case, the discharge temperature of the mixture was adjusted to 155 to 160°C by controlling the temperature of the mixer. After cooling, in the third stage of kneading, sulfur and vulcanization accelerators 1 and 2 were added and kneaded using an open roll set at 70°C. Thereafter, the product was molded and vulcanized in a vulcanization press at 160°C for 20 minutes. The rubber compositions before and after vulcanization were evaluated. Specifically, the evaluation was performed by the following methods. The results are shown in Tables 23 to 29.

[0390] [Evaluation of characteristics] (Evaluation 1) Compound Mooney Viscosity The compound obtained above after the second mixing step and before the third mixing step was used as a sample, and the viscosity was measured using a Mooney viscometer in accordance with ISO 289 after preheating at 130°C for 1 minute and rotating the rotor at 2 revolutions per minute for 4 minutes. The result of Comparative Example 2-5 was set to 100 and indexed. The smaller the index, the better the processability.

[0391] (Evaluation 2) Tensile strength and tensile elongation The tensile strength and tensile elongation were measured according to the tensile test method of JIS K6251, and indexed with the result of Comparative Example 2-5 set at 100. A larger index indicates better tensile strength and tensile elongation (breaking strength).

[0392] (Rating 3) Abrasion resistance Using an Acron abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the amount of wear was measured at a load of 44.4 N and 1000 revolutions in accordance with JIS K6264-2, and indexed with the result of Comparative Example 2-5 set at 100. A higher index indicates better abrasion resistance.

[0393] (Evaluation 4) Viscoelastic parameters Viscoelastic parameters were measured in torsion mode using a viscoelasticity tester "ARES" manufactured by Rheometrics Scientific Co., Ltd. Each measured value was indexed with the result for the rubber composition of Comparative Example 2-5 set at 100. Tan δ measured at 0°C, a frequency of 10 Hz, and a strain of 1% was used as an index of wet skid resistance. A higher index value indicates better wet skid resistance. In addition, tan δ measured at 50°C, a frequency of 10 Hz, and a strain of 3% was used as an index of fuel economy. The smaller the index, the better the fuel economy. Furthermore, the elastic modulus (G') measured at 50°C, a frequency of 10 Hz, and a strain of 3% was used as an index of steering stability. A higher index value indicates better steering stability.

[0394] [Table 23]

[0395] [Table 24]

[0396] [Table 25]

[0397] [Table 26]

[0398] [Table 27]

[0399] [Table 28]

[0400] [Table 29]

[0401] As shown in Tables 23 to 29, in Examples And reference examples Compared with Comparative Examples 2-5 to 2-8, Nos. 2-41 to 2-80 were confirmed to have low compound Mooney viscosity when vulcanized and good processability, and to have excellent abrasion resistance, handling stability and breaking strength when vulcanized, and to have an excellent balance between low hysteresis loss and wet skid resistance. [Industrial Applicability]

[0402] The branched conjugated diene polymer obtained by the production method of the present invention has industrial applicability in the fields of tire treads, interior and exterior parts of automobiles, anti-vibration rubber, belts, footwear, foams, various industrial products, and the like.

Claims

1. a polymerization step of polymerizing or copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene polymer having an active terminal; a branching step of reacting an active terminal of the conjugated diene polymer with a styrene derivative as a branching agent to introduce a branched structure; a reaction step of reacting a coupling agent or a polymerization terminator with the active terminal of the conjugated diene polymer obtained in the branching step, Furthermore, The coupling agent or the polymerization terminator has a nitrogen atom-containing group. A method for producing a branched conjugated diene polymer.

2. The method further comprises a step of adding a conjugated diene compound and / or an aromatic vinyl compound to the reaction system during and / or after the branching step. A method for producing the branched conjugated diene polymer according to claim 1.

3. The method for producing a branched conjugated diene-based polymer according to claim 1 or 2, wherein the polymerization terminator is an alkoxy compound having a nitrogen atom-containing group.

4. The styrene derivative is a compound represented by the following formula (1) and / or the following formula (2): A method for producing the branched conjugated diene polymer according to any one of claims 1 to 3. 【Chemistry 1】 【Chemistry 2】 (In formulas (1) and (2), R 1 represents any one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. X 1 , X 2 , X 3 is a single bond or an organic group containing any one selected from the group consisting of carbon, hydrogen, nitrogen, sulfur, and oxygen. Y 1 , Y 2 , Y 3 represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. Each may be independent and the same or different.

5. In the formula (1), R 1 is a hydrogen atom, and Y 1 is any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom.

6. In the formula (2), X 1 is a single bond, Y 2 is any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom.

7. In the formula (1), R 1 is a hydrogen atom, and Y 1 The method for producing a branched conjugated diene polymer according to claim 4, wherein is an alkoxy group having 1 to 20 carbon atoms or a halogen atom.

8. In the formula (2), Y 2 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom; Y 3 The method for producing a branched conjugated diene polymer according to claim 4, wherein is an alkoxy group having 1 to 20 carbon atoms or a halogen atom.

9. In the formula (1), R 1 is a hydrogen atom, and Y 1 The method for producing a branched conjugated diene polymer according to claim 4, wherein is an alkoxy group having 1 to 20 carbon atoms.

10. In the formula (1), R 1 is a hydrogen atom, and X 1 is a single bond, and Y 1 The method for producing a branched conjugated diene polymer according to claim 4, wherein is an alkoxy group having 1 to 20 carbon atoms.

11. In the formula (2), X 2 is a single bond, and Y 2 is an alkoxy group having 1 to 20 carbon atoms or a halogen atom; 3 is a single bond, and Y 3 The method for producing a branched conjugated diene polymer according to claim 4, wherein is an alkoxy group having 1 to 20 carbon atoms or a halogen atom.

12. In the polymerization step, a nitrogen atom-containing vinyl compound is copolymerized, or The method further comprises a step of copolymerizing a conjugated diene compound and a nitrogen atom-containing vinyl compound, or a conjugated diene compound, a vinyl aromatic compound and a nitrogen atom-containing vinyl compound. A method for producing the branched conjugated diene polymer according to any one of claims 1 to 11.

13. The nitrogen atom-containing vinyl compound is A compound represented by the following formula (3) or (4): A method for producing the branched conjugated diene polymer according to claim 12. 【Chemistry 3】 (In formula (3), R 7 ~R 9 each independently represents any one selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms; R 10 is a single bond or a chain with NR 13 It represents a divalent hydrocarbon group having 1 to 6 carbon atoms which may be interrupted by any one of O and S. R 11 ~R 13 each independently represents any one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, and a tri-substituted silyl group having an alkyl group having 1 to 30 carbon atoms and / or an aryl group having 6 to 30 carbon atoms on the silicon atom. 【Chemistry 4】 (In formula (4), R 7 ~R 9 each independently represents any one selected from the group consisting of hydrogen, an alkyl group having 1 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms; R 10 is a single bond or a chain with NR 13 It represents a divalent hydrocarbon group having 1 to 6 carbon atoms which may be interrupted by any one of O and S. R 13 each independently represents any one selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, and a tri-substituted silyl group having an alkyl group having 1 to 30 carbon atoms and / or an aryl group having 6 to 30 carbon atoms on the silicon atom. X is NR in the middle of the chain 14 , O or S, and represents a saturated ring-forming moiety in which all of the carbon-carbon bonds are single bonds, or an unsaturated ring-forming moiety in which at least a portion of the carbon-carbon bonds are double bonds. R 14 represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms.

14. In the reaction step, reacting an active terminal of the conjugated diene polymer obtained in the branching step with a coupling agent represented by the following formula (S-2): A method for producing the branched conjugated diene polymer according to any one of claims 1 to 13. 【Chemistry 5】 (In formula (S-2), R 1 ~R 8 each independently represents any one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, and may be the same or different. X 1 and X 4 is either (i) or (ii) below. (i) X 1 and X 4 A portion of the group is a group selected from the group consisting of an alkoxyl group having 1 to 5 carbon atoms, a hydrocarbon group containing a 2-pyrrolidonyl group, and a group containing an epoxy group having 4 to 12 carbon atoms, and the remainder is a group derived from these groups or a single bond. (ii) X 1 and X 4 is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, X 1 and X 4 may be the same or different. X 2 is a group selected from the group consisting of an alkoxyl group having 1 to 5 carbon atoms, a hydrocarbon group containing a 2-pyrrolidonyl group, and a group containing an epoxy group having 4 to 12 carbon atoms, and the remainder is a group derived from these groups or a single bond. X 3 is a group containing 2 to 20 repeating alkylene glycol units. m is an integer from 3 to 200, n is an integer from 0 to 200, and k is an integer from 0 to 200.

15. A step of obtaining a branched conjugated diene polymer by the production method according to any one of claims 1 to 14; obtaining a rubber component containing 10% by mass or more of the branched conjugated diene polymer; A filler is added to 100 parts by mass of the rubber component. a step of obtaining a rubber composition by adding 5.0 parts by mass or more and 150 parts by mass or less of the carboxylic acid or carboxylic acid derivative to the rubber composition; The method for producing a rubber composition comprising the steps of:

16. Obtaining a rubber composition by the method for producing a rubber composition according to claim 15; molding the rubber composition to obtain a tire; A tire manufacturing method comprising the steps of:

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